du.sePublications
Change search
Refine search result
1234567 1 - 50 of 303
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • chicago-author-date
  • chicago-note-bibliography
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Abd Alrahman, Chadi
    Dalarna University, School of Technology and Business Studies, Electrical Engineering.
    Evaluation of a PVT Air Collector2015Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Hybrid Photovoltaic Thermal (PVT) collectors are an emerging technology that

    combines PV and solar thermal systems in a single solar collector producing heat and

    electricity simultaneously. The focus of this thesis work is to evaluate the performance of

    unglazed open loop PVT air system integrated on a garage roof in Borlänge. As it is

    thought to have a significant potential for preheating ventilation of the building and

    improving the PV modules electrical efficiency. The performance evaluation is important

    to optimize the cooling strategy of the collector in order to enhance its electrical efficiency

    and maximize the production of thermal energy. The evaluation process involves

    monitoring the electrical and thermal energies for a certain period of time and investigating

    the cooling effect on the performance through controlling the air mass flow provided by a

    variable speed fan connected to the collector by an air distribution duct. The distribution

    duct transfers the heated outlet air from the collector to inside the building.

    The PVT air collector consists of 34 Solibro CIGS type PV modules (115 Wp for each

    module) which are roof integrated and have replaced the traditional roof material. The

    collector is oriented toward the south-west with a tilt of 29 ᵒ. The collector consists of 17

    parallel air ducts formed between the PV modules and the insulated roof surface. Each air

    duct has a depth of 0.05 m, length of 2.38 m and width of 2.38 m. The air ducts are

    connected to each other through holes. The monitoring system is based on using T-type

    thermocouples to measure the relevant temperatures, air sensor to measure the air mass

    flow. These parameters are needed to calculate the thermal energy. The monitoring system

    contains also voltage dividers to measure the PV modules voltage and shunt resistance to

    measure the PV current, and AC energy meters which are needed to calculate the

    produced electrical energy. All signals recorded from the thermocouples, voltage dividers

    and shunt resistances are connected to data loggers. The strategy of cooling in this work

    was based on switching the fan on, only when the difference between the air duct

    temperature (under the middle of top of PV column) and the room temperature becomes

    higher than 5 °C. This strategy was effective in term of avoiding high electrical

    consumption by the fan, and it is recommended for further development. The temperature

    difference of 5 °C is the minimum value to compensate the heat losses in the collecting

    duct and distribution duct.

    The PVT air collector has an area of (Ac=32 m2), and air mass flow of 0.002 kg/s m2.

    The nominal output power of the collector is 4 kWppv (34 CIGS modules with 115

    Wppvfor each module). The collector produces thermal output energy of 6.88 kWth/day

    (0.21 kWth/m2 day) and an electrical output energy of 13.46 kWhel/day (0.42 kWhel/m2

    day) with cooling case. The PVT air collector has a daily thermal energy yield of 1.72

    kWhth/kWppv, and a daily PV electrical energy yield of 3.36 kWhel /kWppv. The fan energy

    requirement in this case was 0.18 kWh/day which is very small compared to the electrical

    energy generated by the PV collector. The obtained thermal efficiency was 8 % which is

    small compared to the results reported in literature for PVT air collectors. The small

    thermal efficiency was due to small operating air mass flow. Therefore, the study suggests

    increasing the air mass flow by a factor of 25. The electrical efficiency was fluctuating

    around 14 %, which is higher than the theoretical efficiency of the PV modules, and this

    discrepancy was due to the poor method of recording the solar irradiance in the location.

    Due to shading effect, it was better to use more than one pyranometer.

  • 2.
    Abdi, Faisa
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Farah, Muse
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Energieffektivisering av Limatvätten AB: Värmeåtervinning från manglar2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Energy efficiency is in the interest of all industries, as it involves the reduction of both energy and cost. The purpose of this project for a bachelor’s degree is to analyse potential energy recovery of waste heat from an ironer.

    The work was carried out at Limatvätten AB, which is a large and modern laundry facility. Limatvätten AB is a textile service company that has been in existence for 50 years. The Lima laundry’s main customers are from the hotel and restaurant business. Limatvätten AB has its own textiles that are rented to hotels, conferences, etc. The largest customers are in Sälenfjällen and in the Siljan region.

    The work is done by identifying moisture, temperature and dynamic pressure in an ironer Based on measurements, the amount of energy that can be recycled is calculated. Heat recovery system proposals are also given in the report. Aquavent is a heat exchanger that uses ventilation heat from the ironers. The water that is heated in the aquavent is led into the washing pipes, which leads to the reduction of steam consumption in washing processes. Temperature change depends on the heat exchanger's efficiency, the higher the temperature change, the more amount of energy recovery is obtained.

    After identification of the problem, a timetable was mapped, and appropriate instruments and interesting parameters were chosen. The moisture content, temperature and dynamic pressure have been measured. The equations described in the theory section are used for most of the calculations with the help of Excel.

    According to the result, the energy saving will be 184 MWh/year if all excess heat from a mangle is reused. Based on the result, the total savings potential is SEK 57 000 /year. According to the results, it is shown that there is the potential to use excess heat from the Lima wash ironers. In addition to the saving of energy, climate impact is also reduced, as the excess energy is again reused which would otherwise disappear into the atmosphere. If two of the ironers are coupled with a heat recovery system, it results in a doubling on the savings potential.

  • 3.
    Abrahamsson, Jonas
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Lindqvist, Jakob
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Nedsmutsade värmesystems påverkan på energisystemet: Effektivisering vid användning av rengöringsmetoder2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Contamination of the heating system is not a well-known problem that can have major economic consequences. Due to minerals and low pH in the system arises limescale and corrosion that can clog the system and can damage components. This will result in increased energy consumption for users and a higher energy input from the district heating company. The purpose of this work is to study different cleaning methods for heating systems and if it is viable with cleaning of heating systems. The cleaning effect on the district heating demand and how it affects greenhouse gas emissions and primary energy use. And examine whether the maintenance of the heating system provides less energy than remodeling the building envelope. Previous studies in this area were examined and relevant data were collected after talks with interesting companies working with cleaning of heating systems. Cleaning the heating system was compared with various packages such as remodeling of the building envelope and heat recovery ventilation. Cleaning the heating systems with an efficiency of 10 % resulting in a reduced heating need at 1,63 GWh per year and a reduction in emissions of 177 tonnes CO2e per year. The reduced heating demand resulted in a reduction in primary energy consumption by 113 750 kWh per year. Installation of the cleaning systems can result in a saving for Tunabyggen of 759 200 SEK per year. The conclusion of this work is that the cleaning prolongs the lifetime of heating systems, but can’t replace remodeling of the building envelope in terms of reduced energy consumption.

  • 4.
    Abreu Saraiva Freitas, Iuri
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Indoor climate: A comparison of residential units in Tjärna Ängar, Borlänge before and after retrofitting2018Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This study try to understand which aspects were fundamental to indoor climate and how to obtain them in order to provide the best possible experience in the thermal comfort of individuals. Thus, arose the studies of Fanger, which was the seed for a new era of discoveries in the area and founded the knowledge our society have today in this globally used standards and norms. Referring to these fundamental aspects of the indoor comfort, data collection was taken in situ to show in details what was happening. This study was executed in order to demonstrate the differences between the data previous and after a process of retrofitting in dwellings built in the 60s and 70s of the century past, in the district of Tjärna Ängar, Borlänge, Sweden. The comparative results using criteria such as Predicted Mean Vote (PMV), Predicted Percentage Dissatisfied (PPD), Draft Rate (DR), air velocity, Mean Radiant Temperature (MRT), Relative Humidity (RH) and air temperature, showed an improvement in 6 of the 8 parameters analyzed. Confirming the expectation that through the retrofitting the residents will be more satisfied, obtain better quality of indoor climate comfort and also increase occupied area in these dwellings.

  • 5.
    Ahamed, Anees
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Accelerated Aging of First-surface Enhanced Aluminum Solar Reflectors under Damp Heat Conditions2016Independent thesis Advanced level (degree of Master (Two Years)), 25 credits / 37,5 HE creditsStudent thesis
    Abstract [en]

    Solar reflectors are one of the main components of concentrating solar power systems. With new products being developed, durability studies become a necessity for assessing the feasibility of commercial application. In this project, accelerated aging of three types of first-surface enhanced aluminum reflectors and one type of second-surface silvered thick glass mirror under damp heat conditions is studied. The project is conducted at the Plataforma Solar de Almería (PSA), in collaboration with German Aerospace Center (DLR), and Center for Energy, Environment and Technology (CIEMAT), Spain.

     

    The study is centered on analyzing the effect of soiling on degradation of reflectors. In addition to conventional methods, space resolved specular reflectometry is utilized for comparative purpose. Damp heat test conditions are simulated in a climatic test chamber. Test is conducted with reference to International Electrotechnical Commission standard IEC 62108 10.7a: damp heat test guidelines. The reflector samples are artificially soiled with natural and synthetic test sands of varying composition. Reflector performance is assessed based on the reduction in monochromatic specular reflectance.

     

    From the tests, a comparative assessment of the candidate reflectors is obtained. Aluminum samples suffered higher degradation than silvered glass mirrors. Aluminum reflectors with polymer top coat permanently retained soil residue. It is observed that presence of chlorides and organic components caused corrosion on all the types of reflectors tested. Surface roughening is the reason for performance deterioration in most of the cases. By comparing different reflectance measurement methods, the significance of total area of the measurement spot in the measurement procedures could be highlighted. It is suggested that for studies involving artificial soiling, the grain size of sand is to be factored in.

  • 6.
    Ahmadi Moghadam, Parham
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Steel Sheet Applications and Integrated Heat Management2016Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Increasing energy use has caused many environmental problems including global warming. Energy use is growing rapidly in developing countries and surprisingly a remarkable portion of it is associated with consumed energy to keep the temperature comfortable inside the buildings. Therefore, identifying renewable technologies for cooling and heating is essential. This study introduced applications of steel sheets integrated into the buildings to save energy based on existing technologies. In addition, the proposed application was found to have a considerable chance of market success.

    Also, satisfying energy needs for space heating and cooling in a single room by using one of the selected applications in different Köppen climate classes was investigated to estimate which climates have a proper potential for benefiting from the application. This study included three independent parts and the results related to each part have been used in the next part.

    The first part recognizes six different technologies through literature review including Cool Roof, Solar Chimney, Steel Cladding of Building, Night Radiative Cooling, Elastomer Metal Absorber, and Solar Distillation. The second part evaluated the application of different technologies by gathering the experts’ ideas via performing a Delphi method. The results showed that the Solar Chimney has a proper chance for the market.

    The third part simulated both a solar chimney and a solar chimney with evaporation which were connected to a single well insulated room with a considerable thermal mass. The combination was simulated as a system to estimate the possibility of satisfying cooling needs and heating needs in different climate classes. A Trombe-wall was selected as a sample design for the Solar Chimney and was simulated in different climates. The results implied that the solar chimney had the capability of reducing the cooling needs more than 25% in all of the studied locations and 100% in some locations with dry or temperate climate such as Mashhad, Madrid, and Istanbul. It was also observed that the heating needs were satisfied more than 50% in all of the studied locations, even for the continental climate such as Stockholm and 100% in most locations with a dry climate. Therefore, the Solar Chimney reduces energy use, saves environment resources, and it is a cost effective application. Furthermore, it saves the equipment costs in many locations. All the results mentioned above make the solar chimney a very practical and attractive tool for a wide range of climates.

  • 7.
    Aishwarya, Veena Aishwarya
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Effects of Soling on the Solar Radiation Sensors for Indian Climatic Conditions2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The satisfaction and elation that accompany the successful completion of any task

    would be incomplete without the mention of the people who have made it possible. It is a great

    privilege to express my gratitude and respect to all those who have guided me and inspired me

    during the period of the project work.

    First and foremost, I express my sincere gratitude to my University professor

    Fiedler Frank, Program Coordinator, Dalarna University, Borlange, Sweden who encouraged

    and permitted me to have my project in the second semester itself.

    I owe a lot to my supervisor Rönnelid Mats, Associate Professor of Energy and

    Environmental Technology, Dalarna University, Borlange, Sweden for his valuable

    suggestions, constructive criticism and encouragement for the project.

    I deem it to be a great privilege in thanking my external supervisor Dr.Richard

    Meyer, Founder and Managing Director (Suntrace GmbH) and Marko Schwandt, Advisor, Solar

    Expert en Suntrace GmbH for giving an opportunity to work under him. Their guidance,

    academic freedom and co-operation have helped me in completing my project.

    My heartfelt thanks to Dr. S. Gomathinayagam, Director General, NIWE and Dr.G.Giridhar,

    Deputy Director General & Head, SRRA department, NIWE for providing me the necessary

    facilities for the completion of my masters project. I am indebted to Dr.Indradip Mitra,Senior

    Technical Advisor at GIZ GmbH and Kaushal Chhatbar, Project Manager, Project

    Development at Suntrace GmbH , for their valuable suggestions and support.

    I also pay my sincere regards to the staffs of SRRA department for their support

    during the period of my project. I owe a lot to my family, who always motivated me and brought

    me to this level. Finally I submit my obeisance to THE ALMIGHTY for constantly supporting

    me and blessing me with the necessary strength to carry out this research.

  • 8.
    Alayan, Sophia
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Design of a PV-Diesel Hybrid System with Unreliable Grid Connection in Lebanon2016Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis is a study on integration of photovoltaic generators into an existing diesel-unreliable grid connected system at the Lebanese village of Khiam. The main goal of implementing PV-diesel hybrid system is to reduce diesel consumption and the import of fossil fuel used in electricity power supply. Before designing the system, it is necessary to create a load profile for 120 households and pre-design the size of the PV generator, the capacity of storage system and inverter type/size selection. The load profile data is based on the average of monthly energy consumption gathered from Khiam village households.

    Detailed simulations and financial analysis are performed with HOMER to compare different systems and their viability. The simulations include four different designs starting from the existing system, diesel generator with unreliable grid, followed by PV generator and unreliable grid, PV and diesel generator and ended with the complete hybrid system. Once the Hybrid system is determined a detailed design is done to optimize the lowest cost PV-diesel hybrid system. The final simulated PV-diesel hybrid system is suggested with a PV capacity of 270 kWp, existing diesel capacity with 200 kVA, an inverter output of 115 kW and battery bank nominal capacity is 1872 kWh. The system renewable fraction is 53% and the project life cycle is 25 years. The PV-diesel hybrid system is projected to produce electricity at a cost of 0.12 USD/kWh. This cost is significantly lower than the 0.26 USD/kWh paid to the diesel operator, as well as lower than 0.13 USD/kWh paid to the utility grid.

    In addition, and according to the given information from the owner, an estimated diesel consumption of 104000 ltr/year, the simulation result shows diesel consumption at 40000 ltr/year. The reduced carbon dioxide production by 65%, from 776 to 272 tons per year, provides further justification for the PV installation in a commercial PV-diesel hybrid system.

  • 9.
    Alfadel, Usama
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Analysing the Peak Shaving Effect and the Increase in SelfConsumption and Self Sufficiencyof Battery Storage When Coupledto a Single Family House2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The aims of the study were to investigate the increase in self-consumption and self-sufficiency and the peak shaving effect of batteries when added to a PV system dimensioned to supply the electric demand of a low energy house built in Sweden. The simulated batteries were Li-ion and the study had a 15-minutes temporal resolution. The study took only the technical aspect of batteries into account and disregarded the economic aspect. A data set of measurements from two near-zero-energy houses built by the Research Institute of Sweden (RISE) was used as inputs. The first house provided measured load profile for an automated load and measured PV production from its 3.6 kW

    p system, the second house provided a load profile for a normal human interactive load. The measured PV production from the 3.6 kWp PV system was compared to the PV production from a simulated 3.6 kWp system taken from PVsyst and System Advisor Model (SAM) and by using different weather data profiles for the simulations. The global irradiance values from the used weather profile data were compared to demonstrate the difference in its values and its effect on the simulated PV production. This comparison between the measured PV production and the simulated one was done because most of the PV simulation software does not take measured PV production as input but they simulate their own PV production based on their built-in weather data; including the software used in this study SAM. The first house with the automated load had an annual energy consumption of Ca. 3600 kWh / Year. The second house with its human interactive load had an annual energy consumption of Ca. 6000 kWh / Year. The load profile was taken as a whole and then divided to different types; heat pump, ventilation and remaining load which represents house hold services. The effect of the input load profile types and its temporal resolution was clarified; this effect came in consistency to what was concluded from the literature review. Different simulations were done varying battery sizes, voltage level, coupling method, dispatch algorithm and other parameter. Three different dispatch algorithms were used for the simulations; two are designed for peak shaving and are built-in tools in SAM while the third algorithm is called Target Zero and designed for maximizing self-consumption and self-sufficiency, it was found in a reference so it was executed in MS Excel. Each of the algorithms used was found to affect both the peaks and the self-consumption and self-sufficiency of the system after adding the batteries compared to before, one as a major effect and the other as a byproduct effect. The peak shaving results varied by varying the batteries and the dispatch algorithm used, for the peak shaving algorithms from SAM, a general decrease in peaks value was reached. For the Target Zero algorithm which optimizes on self-consumption and self-sufficiency, a decrease in the number of the peaks was reached. Both decreases happened by increasing battery sizes. For the self-consumption and self-sufficiency effect, an increase happened with its highest value for 7.2 kWh batteries and by using the three different algorithms. The effect of the load type was also demonstrated by comparing the simulations results for the heat pumps from both houses since both heat pumps were found to have the highest effect on the results. The study was concluded by emphasizing the added values of batteries when coupled to a behind-the-meter PV system. The study could have been more precise and added more information to this field if it had a 1 minute temporal resolution simulations, but patching one minute temporal resolution load profile takes a long time. Working with one minute load profile requires one minute weather profile for the PV simulation which is normally only commercial. Also, having a weather station installed at the house to measure the solar irradiance to be used in the simulation instead of using different weather profiles would have added more accuracy to this paper.

  • 10.
    Alhamwi, MHD Mouaz
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Evaluating the Economic Feasibility for utilizing PV Power Optimizers in Large-scale PV Plants for The Cases of Soiling, Mismatching, and Degradation2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The solar PV modules are influenced by a variety of loss mechanisms by which the energy yield is affected. A PV system is the sum of individual PV modules which should ideally operate similarly, however, inhomogeneous soiling, mismatching, and degradation, which are the main focus in this study, lead to dissimilarities in PV modules operating behavior and thus, lead to losses which will be assessed intensively in terms of energy yield.

    The dissimilarities in PV modules are referred to the ambient conditions or the PV modules

    characteristics which result in different modules’ maximum power point (MPP) and thus, different currents generated by each PV modules which cause the mismatching. However, the weakest PV module current governs the string current, and the weakest string voltage governs the voltage.

    Power optimizers are electronic devices connected to the PV modules which adjust the voltages of the PV modules in order to obtain the same current as the weakest module and thus, extract

    the modules’ MPP. Hence, the overall performance of the PV plant is enhanced. On the other hand, the power optimizers add additional cost to the plant’s investment cost and thus, the extra energy yield achieved by utilizing the power optimizers must be sufficient to compensate the additional cost of the power optimizers. This is assessed by designing three systems, a reference system with SMA inverters, a system utilizes Tigo power optimizers and SMA inverters, and a system utilizes SolarEdge power optimizers and inverters. The study considers four different locations which are Borlänge, Madrid, Abu Dhabi, and New Delhi.

    An Excel model is created and validated to emulate the inhomogeneous soiling and to evaluate the economic feasibility of the power optimiz

    ers. The model’s inputs are obtained from PVsyst and the precipitation data is obtained from Meteoblue and SMHI database.

    The economic model is based on the relation between Levelized Cost of Electricity (LCOE) which will be used to derive the discount rate. Graphs representing the discounted payback period as a function of the feed-in tariff for different discount rates is created in order to obtain the discounted payback period.

    The amount of extra energy yielded by the Tigo and the SolarEdge systems is dependent on the soiling accumulated on the PV modules. Relative to the reference system, 6.5 % annual energy gain by the systems utilizing the power optimizers in soiling conditions, up to 2.1 % in the degradation conditions, and up to 9.7 % annual energy gain at 10 % mismatching rate. The extra energy yield is dependent on the location, however, the Tigo and the SolarEdge systems have yielded more energy than the reference system in all cases except one case when the mismatch losses is set to zero.

    The precipitation pattern is very influential, and a scare precipitation leads to a reduction in the energy yield, in this case, the Tigo and the SolarEdge systems overall performance is enhanced and the extra energy gain becomes greater.

    The Tigo system yield slightly more energy than the SolarEdge system in most cases,

    however, during the plant’s lifetime, the SolarEdge system could become more efficient than the Tigo system which is referred to the system’s sizing ratio. The degradation of the system or the soiling accumulation decreases the irradiation and thus, a slightly oversized PV array become suitable and deliver an optimal power to the inverters.

    The SolarEdge system is feasible in all scenarios in terms of LCOE and discounted payback period, although its slightly lower performance relative to the Tigo system, this is referred to its low initial cost in comparison to the other systems. The Tigo system is mostly infeasible although it yields more energy than the reference and the SolarEdge systems, this is referred

    iii

    to its relatively high initial cost. However, feed-

    in tariffs higher than 20 € cent / kWh make

    all systems payback within less than 10 years.

    The results have overall uncertainty within ± 6.5 % including PVsyst, Excel model, and the

    precipitation uncertainties. The uncertainty in the degradation and the mismatching

    calculations is limited to PVsyst uncertainty which is ± 5 %. The uncertainties in LCOE in

    the location of New Delhi, since it is the worst-case scenario, are 5.1 % and 4 % for the

    reference and the systems utilizing power optimizers, respectively.

    Consequently, accommodating the uncertainties to the benefits gained by utilizing power

    optimizers indicates that the energy gain would oscillate in the range of 6 % - 6.9 % for the

    soiling calculations, 2 % - 2.2 % for the degradation simulations, and 9.2 % - 10.2 % for the

    mismatching simulations at 10 % mismatchrate.

  • 11.
    Al-Hashimi, Mazin
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Modelling Installation Cost for Rooftop PV Systems2015Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The cost of installation of photovoltaic (PV) systems is a substantial fraction of the total cost of the project and the same is increasing with reducing cost of PV modules. This study essentially deals with the cost of installation of rooftop PV systems and presents a cost model for it, based on data collected for more than 700 projects of different capacities, roof types, circumstances, and locations in Sweden. The presented cost model shall give reasonably accurate estimations about the costs associated with the main elements of the process of rooftop PV systems installation, such as labour, shipping, equipment, travel, and accommodation, for different situations as a function of few important variables such as system capacity, roof type, distance to the installation location, etc. The weighted share of cost of the different elements of the cost model out of the total cost of installation was determined. Several relationships between different elements and variables were examined to find relationships that can help to better understand the process of installation and to develop the cost model. The variations in time required per unit system capacity have been examined for several processes of rooftop PV systems installation, to investigate about potential for reduction in the time and thus the cost due to economies of scale.

  • 12.
    Alkhado, Luqman
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Boussaa, Youcef
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Heat transfer tests on EPS material and massive timber wall component2018Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Timber walls are known to be an energy efficient component in the building envelope.

    These building elements are essential in the passive design and have been pointed out to

    their ability to regulate the indoor climate and reduce energy demand. Heat transfer

    measurements of thermal transmittance value of Iso-timber wall component have been

    performed with the climate chamber at three temperature differences. The influence of

    temperature variations on the thermal conduction of the wall were investigated. The

    temperature on the warm side was kept at room temperature 20 °C while the cold side

    temperature was decreased from 0 C to -20 C during the tests. As the temperature

    difference is increased, the thermal transmittance value of the timber wall component

    decreased slightly due to decrease in the thermal conductivity value. The effect of density

    and porosity on the thermal conductivity may be related to the presence of air voids and

    cell boundaries inside the timber wall. Results have showed that the U-value of the timber

    wall component decreases at higher temperature differences which indicates the higher

    degree of insulation of the timber wall component.

  • 13.
    Almsalati, Hussam
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Life cycle assessment of villas made by Fiskarhedenvillan, comparison between wood and brick facade2018Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Awareness of climate change has resulted in enormous challenges for developed and

    developing countries. The frightening truth about our environmental situation has led to

    investigations of the causes of these changes and to obstruct these sources gradually but

    quickly. The alarming increase of average temperature of the earth has caused much worry

    around the world. Gas emissions in the atmosphere greatly affect the environment, where

    CO

    2 emissions is one of the most serious factors contributing to the global warming

    potential. As the building sector emits 40% of global energy use and one-third of global

    greenhouse gas emissions, engineers must be educated to choose the best materials that

    lead to reducing CO

    2 emissions. This means selecting materials that have less negative

    impact on the environment and are more “environmentally friendly”.

    This study shows how much CO

    2e emissions are released into the atmosphere from a

    wooden structure villa that consists of two stories, a storage and a garage, with a total area

    of 229.6m2. The results of this case will be compared to a second case, where the external

    wooden siding is replaced with brick veneer. This result of this comparison provides us

    with a guideline in for how the selected materials impact the environment, illuminating the

    importance in choosing the right materials according to their CO

    2e emission levels. In this

    way, the building sector can actively work to reduce the environmental impact.

    To achieve these goals, this study performed via life cycle assessment LCA methodology

    by using the One-Click LCA program. LCA is identified as a technique to assess the

    environmental impact and resources used through a product’s life cycle. This study utilized

    the LCA methodology (cradle to grave), which means starting from the extraction of raw

    materials, to product production, manufacturing, product usage and its end of life. The

    study lifespan was estimated to be 50 years.

    The results of the study verify that the wooden villa is more environmentally friendly than

    the villa made of brick, where carbon dioxide equivalent emission can be reduced to more

    than half by utilizing wood. Implementing the life cycle assessment study to any building

    aids in making the decision to choose the right materials for building according to CO

    2e

    emission. And in this way, the environmental impact caused by the building sector will be

    greatly reduced.

  • 14.
    Al-Samahiji, Alexander
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Incorporating Solar Energy Into an Aluminium Smelter’s Energy Mix: A study using Aluminium Bahrain2017Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis was aimed at studying the possibility of integrating solar energy in to an existing aluminium smelter in the Kingdom of Bahrain owned by Aluminium Bahrain (ALBA). The smelter was powered by its own in-house natural gas fed power plants. ALBA was chosen as the subject of the study for of two reasons. Firstly, the power station at ALBA was similar in technology to those powering the national grid. Secondly, the nominal power of ALBA was not dissimilar to that of the national grid. This meant that the techniques and technologies investigated were useful in the context of the national grid as well. A literature review was initially conducted to better understand how the current aluminium smelters work, what the possibilities were for introducing solar energy and what has been done previously. The study used publically available information to deduce the energy consumption of the ALBA smelter on an annual basis. For the year 2011 this was found to be in the order of 15.2TWh when ALBA had 2,249MW of nominal plant capacity installed and had consumed about 132MMBCF of natural gas. With the planned pot-line 6 expansion an additional 1,792MW capacity would be added with the corresponding additional gas use and increased energy output. The completion of pot-line 6, scheduled for Q1 2019, would also make ALBA the world’s largest single-site aluminium smelter.  This energy demand information was then used with PVSyst and System Advisor Model simulation software. The aim was to determine what photovoltaic (PV) and concentrated solar power (CSP) energy plants capable of meeting ALBA’s needs would be in terms of power, energy outputs and land usage. Although powering a modern aluminium smelter is possible with today’s solar technology, the area of land required would be very large. It was deduced that using PV fixed tilt arrays, a PV plant of 9.2GWp would be required to deliver the annual energy requirements of ALBA covering a theoretical land area of some 200km2. Utilising CSP plants of central tower and concentric heliostat design would need about 358km2 whereas parabolic trough collector technology would need about 240km2. However a CSP plant utilising linear Fresnel collectors would need about 105km2 of land area. These contiguous land areas are not available in the Kingdom of Bahrain and so alternatives would have to be studied for locating such plants. Another issue would be to find a robust and reliable storage technology to power the plant during the evenings and other times of low solar resource.  It was found that the existing roof areas of ALBA’s pot-lines and cast house would be sufficient to house a PV plant of 6.5MWp utilising standard 250Wp PV modules. This would be larger than the largest plant currently installed in the country which stands at 5MWp developed by Bapco. The plant would produce some 9.7GWh of energy per average year and could be utilised by ALBA. Alternatively, the PV plant could be connected directly to the national grid and thus provide another source of income to ALBA whilst helping in the national drive for harnessing renewable energy. It should be noted that there are more suitable roof areas available at ALBA meaning that the PV plant size could be larger and if more powerful modules are used, the nominal plant capacity would also be increased delivering more annual energy. Due mainly to time constraints, it was not possible to investigate some areas that were highlighted during the course of the study. These included plant costs, energy storage options, modelling and simulating CSP derived heat injection into gas power turbines, water usage requirements and mitigation techniques and the technologies for maintaining the collectors clean and reflective in the harsh desert climate of the country. These are all areas for further work.

  • 15.
    Arguello, Nicolay
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Iñiguez, Enric
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Renewable Energy Emergency Microgrid Optimization in Ludvika2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In the community of Ludvika, a Renewable Energy Emergency Microgrid (REEM) has been defined to provide back-up power during crisis situations. An Energy Storage System (ESS) was designed to support the main loads of the Microgrid in the first working hours. Additionally, the ESS will start-up the hydro power station, which will replace the power supply from the battery after the set-up period. However, the necessity of understanding the operation of the major components, such as the photovoltaic (PV) system and the ESS, of the REEM in normal conditions is imperative.

    This study analyses a variety of scenarios to evaluate how the renewable energy of an isolated system can be managed. Alternatives for increasing self-consumption of PV power and reduce feed-in power in the REEM are investigated. All the solutions consider the complete system design and an additional economic analysis for supporting the decision-making. The results show that selling the energy to the grid is the best economic solution, followed by the distribution of energy. However, the difference of 0.5 % in the total net present cost (TNPC) makes the distribution system, including the ESS, an option to be considered. In the upcoming years, changes on the amount of energy produced by the PV system or increasing the battery capacity usage in normal operation can become more feasible.

  • 16.
    Aylott, Benjamin
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Techno-Economic Evaluation of Distributed Generation within a Community Smart Grid with Demand Side Response Using HOMER2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In this study the distributed generation of renewable energy, primarily photovoltaic power, and consumption of energy within a geographically dispersed smart grid or ‘virtual micro grid’ is simulated using a model based around the HOMER Pro software with the aim of gaining insight into the economic and environmental performance of the system under different assumptions about the configurations of the generators and the presence of low carbon technologies such as heat pumps and electric vehicles. Demand side response for the purpose of reducing carbon emissions was also investigated as part of this.

    As well as simulating the system within HOMER, the study involved constructing a representative load profile for 200 domestic consumers and other loads using existing data, implementing a model for demand side response, using a range of detailed technical and environmental data to configure the HOMER model, and creating custom plotting tools. These features were connected in a data analysis pipeline written in Python included as part of the submission.

    The study found that to improve the environmental and economic performance of the system increasing the amount of renewable generation should be prioritized over other measures, such as demand side response. PV was the easiest to add due to lower upfront costs (compared to battery storage systems and mid-scale wind turbines) and lower financial and regulatory overheads. Carbon emissions were found to be minimized for around 3.5kW of PV per household in this scenario. Including a single mid-scale wind turbine was found to have the potential to greatly increase renewable penetration, and reduce carbon emissions and the cost of energy due to the complementary nature of PV and Wind power production. Battery storage at low penetrations was found to have little impact, but can make a large impact at high penetration but at significant financial expense.

    A range of battery products was also investigated for their suitability for use within the project and future schemes and were evaluated by locating them in the Renewable Fraction/LCOE plane.

    The inclusion of low carbon technologies such as heat pumps and electric vehicles was found to have some negative impact on the performance where only PV is present in the smart grid with little evidence that it can make better use of the renewable power due to poor matching with the available PV generation.

  • 17.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    ClimateWell TDC with District Heat2010Report (Other academic)
    Abstract [en]

    The PolySMART demonstration system SP1b has been modeled in TRNSYS and calibrated against monitored data. The system is an example of distributed cooling with centralized CHP, where the driving heat is delivered via the district heating network. The system pre-cools the cooling water for the head office of Borlänge municipality, for which the main cooling is supplied by a 200 kW compression chiller. The SP1b system thus provides pre-cooling. It consists of ClimateWell TDC with nominal capacity of 10 kW together with a dry cooler for recooling and heat exchangers in the cooling and driving circuits. The cooling system is only operated from 06:00 to 17:00 during working days, and the cooling season is generally from mid May to mid September. The nominal operating conditions of the main chiller are 12/15°C.

    The main aims of this simulation study were to: reduce the electricity consumption, and if possible to improve the thermal COP and capacity at the same time; and to study how the system would perform with different boundary conditions such as climate and load.

    The calibration of the system model was made in three stages: estimation of parameters based on manufacturer data and dimensions of the system; calibration of each circuit (pipes and heat exchangers) separately using steady state point; and finally calibration of the complete model in terms of thermal and electrical energy as well as running times, for a five day time series of data with one minute average data values. All the performance figures were with 3% of the measured values apart from the running time for the driving circuit that was 4% different. However, the performance figures for this base case system for the complete cooling season of mid-May to midSeptember were significantly better than those for the monitoring data. This was attributed to long periods when the monitored system was not in operation and due to a control parameter that hindered cold delivery at certain times. 

  • 18.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy and Environmental Technology.
    European resarch school on large scale solar thermal - SHINE2014In: Solar District Heating 2014, Hamburg, Germany, 2014Conference paper (Other academic)
    Abstract [en]

    The Solar HeatIntegration NEtwork (SHINE) is a European research school in which 13 PhDstudents in solar thermal technologies are funded by the EU Marie-Curie program.It has five PhD course modules as well as workshops and seminars dedicated to PhDstudents both within the project as well as outside of it. The SHINE researchactivities focus on large solar heating systems and new applications: ondistrict heating, industrial processes and new storage systems. The scope ofthis paper is on systems for district heating for which there are five PhDstudents, three at universities and two at companies. The PhD students allstarted during the early part of 2014 and their initial work has concentratedon literature studies and on setting up models and data collection to be usedfor validation purposes. The PhD students will complete their studies in2017-18.

  • 19.
    Bales, Chris
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Andersen, M.
    Bava, F.
    Louvet, Y.
    Peréz de la Mora, N.
    Sotnikov, A.
    Shantia, A.
    SHINE Doctoral School: Results from six PhD studies on large scale solar thermal2016In: 4th International Solar District Heating Conference, 2016Conference paper (Other academic)
    Abstract [en]

    The Solar Heat Integration NEtwork (SHINE) is a European research school in which 13 PhD students in solar thermal technologies are funded by the EU Marie-Curie program. It has five PhD course modules as well as workshops and seminars dedicated to PhD students both within the project as well as outside of it. The SHINE research activities focus on large solar heating systems and new applications: on district heating, industrial processes and new storage systems. The scope of this paper is on systems for district heating for which there are six PhD students, five at universities and one at a company. The initial work concentrated on literature studies and on setting up initial models and measurement setups to be used for validation purposes. The measurements have been used for validating simulation models, including those used for extending the capabilities of the planning tool Polysun to simulate smaller district heating systems. Some results of these studies are presented in the paper. The PhD students will complete their studies in 2017-18.

  • 20.
    Bales, Chris
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Gustafsson, Marcus
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Chiara, Dipasquale
    Roberto, Fedrizzi
    Alessandro, Bellini
    Matteo, D’Antoni
    Fabian, Ochs
    Georgios, Dermentzis
    Sarah, Birchall
    D2.1c Simulation Results of Reference Buildings2014Report (Other academic)
    Abstract [en]

    This report is the third part of the deliverable D2.1, where the other two parts report on the energy consumption in the building stock in Europe based on the available energy statistics (D2.1a) and the energy policies related to buildings (D2.1b).The aim of this report is to give complementary information about the heating and cooling demands of residential and office buildings based on simulations, so that the many gaps in the energy statistics can be filled and the statistics can be critically evaluated. The methodology results in a complete and consistent overview of the heating and cooling demands in residential and office buildings for seven different climate regions covering the whole of the EU and six different periods of construction, covering pre-1945 to post 2000. In addition, the data for the residential building stock is split into single family houses, small and large multifamily houses, while for offices the results are given for low and high rise offices with 6 or 12 office units per floor.The simulation models have been benchmarked (calibrated) against the energy statistics for each of the seven climate regions based on the aggregated data for the whole residential building stock and then for the office building stock in that climate region (in D2.1a). The methodology derives the aggregated average using weighted averages of data split into periods of construction and typology for both energy statistics and simulation results. The weighting is done based on heated and cooled floor area. As nearly all of the energy statistics are given in terms of consumption, while simulation results were calculated as demand, the demand data were converted to consumption data. One fixed conversion factor was used for heating (average efficiency 0.8) and one for cooling (average EER 2.5). Since the calculated demands strongly depend on the imposed heating or cooling set temperatures, this simulation parameter was varied so that the aggregated simulation result was the same as that for the consumption derived from the energy statistics. The calibrated models were then used to derive the average heating and cooling consumptions of the building stock in the seven climate regions.The methodology has a number of uncertainties, both in terms of the energy statistics as well as in terms of the simplifications and assumptions in the simulation models. During the calibration process a number of inconsistencies have been detected for individual countries and climate regions between simulation results and energy use from statistic data. The mismatches are analytically assessed, showing improvements necessary both in terms of statistic data necessary for reliable energy estimations and data to be gathered in order to guarantee consistent simulations outcomes.Beside the building stock survey completion and statistic data quality assessment, the work is also the basis for the definition of suitable Energy Renovation Packages and Products within the iNSPiRe project. The simulation results will be used to identify which building typologies, periods of construction and climate region have the largest potential for impact on the European scenario. Such information will be used within the iNSPiRe project to define reference Target buildings, as virtual demonstration cases to prove the potential improvements and impacts following the renovation process of a given share of the European building stock.

  • 21.
    Bales, Chris
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Lorenz, Klaus
    Application of Polysun in Teaching Courses in Sweden and in the PhD Program SHINE2016In: SIGES Internationale Konferenz zur Simulation gebäudetechnischer Energiesysteme, 2016, p. 90-95Conference paper (Other academic)
  • 22.
    Bales, Chris
    et al.
    Dalarna University, School of Technology and Business Studies, Energy and Environmental Technology.
    Nielsen, Christian
    Dalarna University, School of Technology and Business Studies, Energy and Environmental Technology.
    Peréz de la Mora, Nicolás
    Sotnikov, Artem
    Louvet, Yoann
    Bava, Federico
    Shantia, Alireza
    Lennermo, Gunnar
    Seven Phd Studies on Solar District Heat2014In: EuroSun 2014 / ISES Conference Proceedings (2014), ISES , 2014Conference paper (Other academic)
    Abstract [en]

    The Solar Heat Integration NEtwork (SHINE) is a European research school in which 13 PhD students in solar thermal technologies are funded by the EU Marie-Curie program. It has five PhD course modules as well as workshops and seminars dedicated to PhD students both within the project as well as outside of it. The SHINE research activities focus on large solar heating systems and new applications: on district heating, industrial processes and new storage systems. The scope of this paper is on systems for district heating for which there are six PhD students, three at universities and two at companies. In addition there is a seventh PhD in a Swedish national research school focused on energy efficiency within district heating networks (Reesbe). The initial work has concentrated on literature studies and on setting up initial models and measurement setups to be used for validation purposes. Some results of these studies are presented in the paper. The PhD students will complete their studies in 2017-18.

  • 23.
    Bastholm, Caroline
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Fiedler, Frank
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Techno-economic study of the impact of blackouts on the viability of connecting an off-grid PV-diesel hybrid system in Tanzania to the national power grid2018In: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 171, no 1, p. 647-658Article in journal (Refereed)
    Abstract [en]

    National electrification plans for many countries with a low level of electrification promote the implementation of centralized and decentralized electrification in parallel. This paper explores different ways of utilizing an established off-grid PV-diesel hybrid system when the national grid becomes available. This is a rather unique starting point within the otherwise well-explored area of rural electrification. With particular focus on the impact of blackouts in the national grid, we evaluate the economic viability of some alternatives: to continue to use the off-grid micro-grid, to connect the existing micro-grid with or without battery backup to the national grid, or to use the national grid only. Our simulation results in HOMER demonstrate that with a grid without blackouts, there are few benefits to maintain the existing system. Low grid-connection fees, low tariffs and low revenues from selling excess electricity to the grid contribute to this result despite the fact that the system does not carry any investment costs. With a grid with blackouts, it is beneficial to maintain the system. The extent of blackouts and the load on the system determine which system configuration is most feasible. The results make clear the importance of taking blackouts in the national grid into consideration when possible system configurations are being evaluated. This is rarely quantified in studies comparing different electrification alternatives, but deserves more attention.

  • 24.
    Blackman, Corey
    Dalarna University, School of Technology and Business Studies, Energy Technology. Mälardalens högskola.
    Evaluation of a thermally driven heat pump for solar heating and cooling applications2015Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Exploiting solar energy technology for both heating and cooling purposes has the potential of meeting an appreciable portion of the energy demand in buildings throughout the year. By developing an integrated, multi-purpose solar energy system, that can operate all twelve months of the year, a high utilisation factor can be achieved which translates to more economical systems. However, there are still some techno-economic barriers to the general commercialisation and market penetration of such technologies. These are associated with high system and installation costs, significant system complexity, and lack of knowledge of system implementation and expected performance. A sorption heat pump module that can be integrated directly into a solar thermal collector has thus been developed in order to tackle the aforementioned market barriers. This has been designed for the development of cost-effective pre-engineered solar energy system kits that can provide both heating and cooling.

    This thesis summarises the characterisation studies of the operation of individual sorption modules, sorption module integrated solar collectors and a full solar heating and cooling system employing sorption module integrated collectors. Key performance indicators for the individual sorption modules showed cooling delivery for 6 hours at an average power of 40 W and a temperature lift of 21°C. Upon integration of the sorption modules into a solar collector, measured solar radiation energy to cooling energy conversion efficiencies (solar cooling COP) were between 0.10 and 0.25 with average cooling powers between 90 and 200 W/m2 collector aperture area. Further investigations of the sorption module integrated collectors implementation in a full solar heating and cooling system yielded electrical cooling COP ranging from 1.7 to 12.6 with an average of 10.6 for the test period.

    Additionally, simulations were performed to determine system energy and cost saving potential for various system sizes over a full year of operation for a 140 m2 single-family dwelling located in Madrid, Spain. Simulations yielded an annual solar fraction of 42% and potential cost savings of €386 per annum for a solar heating and cooling installation employing 20m2 of sorption integrated collectors.

  • 25.
    Blackman, Corey
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Experimental Evaluation and Concept Demonstration of a Novel Modular Gas-Driven Sorption Heat Pump2017Conference paper (Refereed)
    Abstract [en]

    Gas-driven sorption heat pumps (GDSHPs) exhibit possibilities in the reduction of energy use and environmental impact of heating systems that utilise natural gas. By utilising renewable thermal energy from the environment, that is, air, ground or water sources, significant reduction of primary energy use can be achieved. However, high cost, low coefficient of performance (COP) and large volume per unit thermal power produced have limited the proliferation of GDSHPs. In this work, exploiting the benefits of reversible chemical reactions in sorption systems, with no internal moving parts, noise, vibration and maintenance-free reactor design, two novel modular prototype sorption components were developed and evaluated experimentally. They were designed to operate as part of an intermittent cycle GDSHP to deliver heat directly to a load or to a stratified hot water store. Prototype 1 was an ammonia-salt basic sorption unit while prototype 2 was an ammonia-salt resorption unit both employing proprietary composite sorbent materials. Test results showed that the prototype 2 reactor produced a specific heating capacity of 46 W/litre at a temperature lift of 50°C yielding a COP of 1.38. Prototype 1 demonstrated higher heating capacity of 73 W/litre at a temperature lift of 70°C but exhibited lower COP of 1.10. Given its higher COP but lower temperature lift, prototype 2 could be employed in a GDSHP designed for moderate heating demands or where a ground source heat exchanger is employed as the low temperature heat source. In the case where a higher temperature lift is required, for example, for an air-source GDSHP unit then the prototype 1 design would be more applicable.

  • 26.
    Blackman, Corey
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Study of Optimal Sizing for Residential Sorption Heat Pump System2017Conference paper (Refereed)
    Abstract [en]

    Gas-driven sorption heat pumps (GDSHP) show significant potential to reduce primary energy use, associated emissions and energy costs for space heating and domestic hot water (DHW) production in residential applications. In this study a bivalent system was considered, characterised by the integration of a novel modular sorption heat pump component and a condensing boiler. The modular heat pump component, or sorption module (SM), has been developed in two types: Type A and Type B, either of which could be integrated into a bivalent GDSHP system. The Type A sorption module had a functioning principle based on a solid chemisorption cycle, while Type B operates under a resorption cycle. To investigate the applicability of each SM type, a bivalent GDSHP system with a Type A SM (GDSHPA) and one with a Type B SM (GDSHPB) were evaluated. Simulations of year-round space heating loads for two single family houses, one in New York and the other Minnesota, were carried out and the seasonal gas coefficient of performance (SGCOP) for each GDSHP system calculated. The impact of the ratio of the design heating capacity of the SM compared to the peak heating capacity of the bivalent GDSHP was studied. Results show that SGCOP was not significantly affected for SM design heating capacity ratios greater than 66% of the peak GDSHPA design capacity in Minnesota, and 21% for GDSHPB. In New York, the ratios were 55% and 35% for GDSHPA and GDSHPB respectively.

  • 27.
    Blackman, Corey
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Test Platform and Methodology for Model Parameter Identification of Sorption Heat Pump Modules2017Conference paper (Refereed)
    Abstract [en]

    Sorption heat pumps are employed in various heat-driven cooling and heat pumping applications. These heat pumps may be driven by solar energy, natural gas, biogas, geothermal energy or waste heat. Given that a plethora of heat sources and sorption materials can be exploited for different applications, various sorption heat pump modules have been developed. The sorption modules are pre-engineered sorption components for increased ease of sorption system development, improved cost effectiveness and reduced system complexity for various applications. However, in the design of sorption modules, component and system modelling and simulation are useful in the process of determining the optimal candidate of several possible sorption working couples for a given application. A test platform has been developed and a test methodology devised for the rapid characterisation of the transient behaviour of the sorption modules. The testing apparatus was used to derive various model parameters to be used for validation of a dynamic sorption module component model. The test method was analogous to that employed for dynamic testing and performance modelling of electrochemical accumulators (i.e. electric batteries) given the similarities between them and sorption modules (also known as thermochemical accumulators). The model parameter identification was based on various heating and cooling power performance parameters as a function of state of charge (SoC) of the sorption modules. A 7-step procedure was used to characterise the performance of the sorption modules based on experimental data. A reference performance for charge and discharge of the sorption modules was measured followed by several measurements at ‘off-reference’ conditions. Performance curves for ‘off-reference’ conditions were then correlated to reference conditions to generate performance curves that describe the transient cooling and heating power delivery of the sorption module at any point within the test range. Results showed that the discharge performance of the sorption modules could be predicted within a reasonable margin of error with a test run sequence of 39 cycles.

  • 28.
    Blackman, Corey
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology. Mälardalen University.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Experimental evaluation of a novel absorption heat pump module for solar cooling applications2015In: Science and Technology for the Built Environment, ISSN 2374-4731, Vol. 21, no 3, p. 323-331Article in journal (Refereed)
    Abstract [en]

    Given the environmental benefits of utilizing free thermal energy sources, such as waste heat and solar energy for cooling purposes, many developments have come about in thermally driven cooling. However, there are still some barriers to the general commercialization and market penetration of such technologies that are associated with system and installation costs, complexity, and maintenance. In efforts to overcome these limitations, a novel absorption heat pump module has been developed and tested. The module comprises a fully encapsulated sorption tube containing hygroscopic salt sorbent and water as a refrigerant, sealed under vacuum, and within which there are no moving parts. The absorption module consists of two main components, one that alternately functions as an absorber or generator and other that alternates between the roles of evaporator and condenser. The module therefore operates cyclically between a cooling delivery phase and a regeneration phase. Each module has a significant energy storage capacity with cooling delivery phases ranging from 6-10 h in length with temperature lifts between 16 degrees C and 25 degrees C. The modules are optimized for integration directly into a solar thermal collector, for roof or facade installation, for daytime regeneration and night-time cooling delivery. Collector integrated modules would be completely modular maintenance-free absorption heat pumps with similar installation requirements to standard solar thermal collectors. This article describes the test method and performance characteristics of the individual absorption modules.

  • 29.
    Blackman, Corey
    et al.
    Dalarna University, School of Technology and Business Studies, Energy and Environmental Technology. Mälardalen University.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy and Environmental Technology.
    Hallström, Olof
    Mälardalen University.
    Demonstration of Solar Heating and Cooling System using Sorption Integrated Solar Thermal Collectors2014In: EuroSun 2014 / ISES Conference Proceedings (2014), ISES , 2014Conference paper (Refereed)
    Abstract [en]

    Producing cost-competitive small and medium-sized solar cooling systems is currently a significant challenge. Due to system complexity, extensive engineering, design and equipment costs; the installation costs of solar thermal cooling systems are prohibitively high. In efforts to overcome these limitations, a novel sorption heat pump module has been developed and directly integrated into a solar thermal collector. The module comprises a fully encapsulated sorption tube containing hygroscopic salt sorbent and water as a refrigerant, sealed under vacuum with no moving parts. A 5.6m2 aperture area outdoor laboratory-scale system of sorption module integrated solar collectors was installed in Stockholm, Sweden and evaluated under constant re-cooling and chilled fluid return temperatures in order to assess collector performance. Measured average solar cooling COP was 0.19 with average cooling powers between 120 and 200 Wm-2 collector aperture area. It was observed that average collector cooling power is constant at daily insolation levels above 3.6 kWhm-2 with the cooling energy produced being proportional to solar insolation. For full evaluation of an integrated sorption collector solar heating and cooling system, under the umbrella of a European Union project for technological innovation, a 180 m2 large-scale demonstration system has been installed in Karlstad, Sweden. Results from the installation commissioned in summer 2014 with non-optimised control strategies showed average electrical COP of 10.6 and average cooling powers between 140 and 250 Wm-2 collector aperture area. Optimisation of control strategies, heat transfer fluid flows through the collectors and electrical COP will be carried out in autumn 2014.

  • 30.
    Blackman, Corey
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Thorin, Eva
    Techno-economic evaluation of solar-assisted heating and cooling systems with sorption module integrated solar collectors2015In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 70, p. 409-417Article in journal (Refereed)
    Abstract [en]

    Currently the use of solar energy for heating and cooling isn't widespread. In order to reduce primary energy consumption in the built environment along with improving the thermal performance of the current building stock, retrofit solutions are required to utilise renewable energy. Using solar energy to reduce primary energy consumption is seen as a possible solution. With the precipitous fall in the prices of crystalline solar photovoltaic modules, utilising this technology to reduce electrical energy consumption for cooling is an attractive solution. Recently, a sorption module integrated collector has been developed in order to improve cost-effectiveness and simplify solar thermal heating and cooling systems. A techno-economic analysis has been performed to evaluate solar photovoltaic cooling and solar thermal cooling systems for residential renewable energy retrofit. The analysis is based on potential energy and cost savings according to simulated heating and cooling loads under climatic conditions of Madrid, Spain. Simplified models were used to determine heating and cooling demands and the solar energy contribution to heating and cooling loads. Additionally, given the sorption collector's unique capacity to store solar energy thermally and provide cooling at night an analysis has been carried out to identify the combined benefit of solar-assisted heating and cooling via photovoltaics during the day and solar sorption at night. For system sizes between 5m(2) and 20m(2) solar fractions between 16% and 64% could be achieved which translated to annual energy cost savings between (sic)153 to (sic)615. (C) 2015 The Authors. Published by Elsevier Ltd.

  • 31.
    Blackman, Corey
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology. SaltX Technology, Hägersten, Stockholm; Mälardalen University.
    Gluesenkamp, Kyle R.
    Malhotra, Mini
    Yang, Zhiyao
    Study of optimal sizing for residential sorption heat pump system2019In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 150, no 5, p. 421-432Article in journal (Refereed)
    Abstract [en]

    Gas-driven sorption heat pumps (GDSHP) show significant potential to reduce primary energy use, associated emissions and energy costs for space heating and domestic hot water production in residential applications. This study considered a bivalent heating system consisting of a sorption heat pump and a condensing boiler, and focuses on the optimal heating capacity of each of these components relative to each other. Two bivalent systems were considered: one based on a solid chemisorption cycle (GDSHPA), and one based on a resorption cycle (GDSHPB). Simulations of year-round space heating loads for two single family houses, one in New York and the other Minnesota, were carried out and the seasonal gas coefficient of performance (SGCOP) calculated. The sorption heat pump’s design heating capacity as a fraction of the bivalent system’s total heating capacity was varied from 0 to 100%. Results show that SGCOP was effectively constant for sorption heat pump design capacity greater than 41% of the peak bivalent GDSHPA design capacity in Minnesota, and 32% for GDSHPB. In New York, these values were 42% and 34% for GDSHPA and GDSHPB respectively. Payback period was also evaluated based on postulated sorption heat pump component costs. The fastest payback was achieved with sorption heat pump design capacity between 22–44%.

  • 32.
    Brandsma, Age
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Performance Evaluation for a Solar Assisted Air Conditioning System in Taipei2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This report shows the study performed at Taipei National University of Technology in Taipei to evaluate the performance of a solar air conditioning system. The performance is evaluated under Taiwan climate conditions. The research is performed under summer weather conditions. No influence is done on these conditions. A solar air conditioning system currently available on the market is used. No changes are made to the system.

    The work to be done is divided into different phases in order to guide the process. First, a literature research is done to find similar research done on this topic and to gain a basic understanding of the topic. Then several measurement plans are made to investigate different parts of the system.. Measurements are done. It is tried to developing a computer model in order to be able to simulate the system performance.

    The overall objective was to gain knowledge about a solar assisted air-conditioning system and develop a model to simulate the system. Initially a list of research questions was made in order to quantify ‘gaining knowledge’ about the system. The plan was to answer them by using measurement data and creating a model to perform simulations. There are measurements done in this report, however due to too many ‘unknowns’* it is difficult to draw conclusions from them. A lot of research questions are still open and they are also not included in this report. It is also not succeeded to make a working model of a solar assisted air conditioner.

    It is succeeded in making a model to predict the performance of the evaporator. This model is currently within 11% accurate.

  • 33.
    Cano Garcia, Jose
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Damp Heat Degradation of CIGS Solar Modules2017Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Due to the short period that some photovoltaic technologies have taken part on the solar energy market, it is crucial to evaluate the long term stability of solar cells belonging to those technologies in order to ensure a minimum lifetime of their performance. Accelerated degradation tests are thus carried out to achieve such goals.

    The present study analyzes the encapsulation effects on co-evaporated manufactured Copper Indium Gallium Selenide (CIGS) solar cells under damp heat conditions, consisting in 85 °C and 85 % relative humidity, during an approximated period of 1000 hours. The experimental procedure has been carried out at Solliance Solar Research facilities.

    Since the encapsulation packages play a critical role as a protection to achieve long term stability of the solar cells and modules, several packaging structures and materials has been taken into study. Thus, eighteen types of mini modules were manufactured including different combinations of encapsulants, front sheet foils, thin film protective barriers and CIGS cells from different manufacturers. The design of these mini modules and the manufacturing process to obtain them is also presented in this work. Various characterization techniques were carried out in order to acquire the required information about the solar cells and encapsulants performance along the damp heat degradation process.

    The results exposed that encapsulation packages including thin film barriers between the encapsulant and the front sheet foil allowed a longer solar cell lifetime due to their remarkable protection against moisture ingress. Moreover, the degradation of the molybdenum layer included in the CIGS cells was found as principal cause of efficiency decrement and end of performance of solar cells protected by regular encapsulant and front sheet foils. Some other findings in relation with the evaluated components are shown along the present study.

  • 34. Cantos-Soto, María Elena
    et al.
    Fernández-García, Aránzazu
    Matteudi, Maud
    Rönnelid, Mats
    Dalarna University, School of Technology and Business Studies, Energy and Environmental Technology.
    Martínez-Arcos, Lucía
    Solar Reflectors Degradation Caused by Simulated Solar Radiation2012In: Solar PACES 2012, 2012Conference paper (Other academic)
    Abstract [en]

    The feasibility of concentrating solar power (CSP) technologies strongly depends on the material used toachieve a suitable solar reflector. A very relevant issue nowadays is to find a cost-effective reflector materialwith appropriate optical properties, able to resist the environmental stress and, therefore, extending itslifetime. This research work is focused on evaluating the thick silvered-glass reflector’s degradation causedby solar radiation onto different solar reflector samples, exposed to both experimental settings, simulatedsunlight under accelerated conditions and solar radiation at real outdoor conditions. The experiments havebeen performed in the optical characterization and durability of solar reflectors laboratory at the PlataformaSolar de Almeria (PSA). Three different chambers were used to reproduce the entire or specifics ranges ofthe solar radiation spectrum. Samples from 6 different manufacturers were placed inside of every sunlightchamber during 2000 hours. The outdoor exposure in the PSA precincts lasted for 4000 hours.

  • 35. Cao, x
    et al.
    Yuan, Y
    Xiang, B
    Sun, L
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Numerical investigation on optimal number of longitudinal fins in horizontal annular phase change unit at different wall temperatures2018In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 158, p. 384-392Article in journal (Refereed)
  • 36. Chen, X
    et al.
    Su, Y
    Aydin, D
    Bai, H
    Jarimi, H
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Raffat, S
    Experimental investigation of a polymer hollow fibre integrated liquid desiccant dehumidification system with aqueous potassium formate solution2018In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 142Article in journal (Refereed)
    Abstract [en]

    Hollow fibres have been studied as the substitute for metallic materials due to the advantages such as light weight, corrosion resistant and low cost in heat and mass transfer applications. A novel polymer hollow fibre liquid desiccant dehumidification system, in which a cross-flow hollow fibre module (fibre inside diameter=1.4mm) serves as the dehumidifier, is presented in this paper. This novel hollow fibre integrated liquid desiccant dehumidification system can be used in an air conditioning system to provide a comfortable indoor environment for hot and humid area. Compared with other conventional liquid desiccant dehumidifier, the polymer hollow fibre has a very small diameter which leads to significantly increased surface area. Moreover, the porous feature of the hollow fibre module can help to eliminate any liquid desiccant droplets carryover into the process air. As a less corrosive and more environmental friendly working fluid, aqueous potassium formate (KCOOH) solution has been selected. The dehumidification performance of the proposed system were analysed experimentally under the conditions of incoming air temperature in the range of 30°C to 45°C. The variations of dehumidification sensible and latent effectiveness, moisture removal rates were studied by varying the incoming air velocity from 0.65 m/s to 4.5m/s. With the various values of incoming air relative humidity in the range of 55% to 75% and the solution concentrations between 36% and 62%, the experimental obtained latent effectiveness are in the range of 0.25 to 0.43 and the sensible effectiveness are in the range of 0.31 to 0.52, which is in a satisfactory agreement with the empirical correlation of effectiveness-NTU in the literature.

  • 37. Chen, X.
    et al.
    Su, Y.
    Aydin, D.
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Ding, Y.
    Reay, D.
    Law, R.
    Riffat, S.
    Experimental investigations of polymer hollow fibre integrated evaporative cooling system with the fibre bundles in a spindle shape2017In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 154, p. 166-174Article in journal (Refereed)
    Abstract [en]

    Due to the advantages of light weight, corrosion resistant and low cost, hollow fibres have been studied as the substitute for metallic materials. A novel hollow fibre integrated evaporative cooling system, in which the hollow fibre module constitutes as the humidifier and the evaporative cooler, is proposed. This novel hollow fibre integrated evaporative cooling system will provide a comfortable indoor environment for hot and dry area. Moreover, the water vapour can permeate through the hollow fibre effectively, and the liquid water droplets will be prevented from mixing with the processed air. In order to avoid the flow channelling or shielding of adjacent fibres, the fibres inside each bundle were made into a spindle shape to allow maximum contact between the air stream and the fibre. The cooling performances of the proposed novel polymer hollow fibre integrated evaporative cooling system were experimentally investigated under the incoming air temperature in the range of 26 °C to 32 °C and relative humidity of 25%–35%. The effects of air velocities on the cooling effectiveness, heat and mass transfer coefficients, specific water consumption and pressure drop across the polymer hollow fibre module were analysed. Two sets of experimentally derived non-dimensional heat and mass transfer correlations were summarized, which could be favourable for the future design of polymer hollow fibre integrated evaporative cooling system.

  • 38.
    Cubillas Camou, Elsa
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Performance Analysis on Photovoltaic Plant in Norway2018Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this study is to analyze the performance of the biggest PV system located in Oslo, Norway. The PV system has a capacity of 130 kW, it started operations in 2014 and it is located on the rooftop of a nursing house managed by the municipality. The analysis was done by making four different comparisons that lead to have a more detailed overview. The comparisons were from the energy production from different years, months and days; the performance ratio from different subsystems; the modeled energy output vs the actual energy output and lastly a relative degradation from different subsystems.

    The thesis was conducted in Kjeller, Norway at the Institute for Energy Technology facilities. Data was collected from two different monitoring systems, the first was from an onsite weather station and the second was from the energy production monitoring system. After collecting all the data, the production comparison from different years, days and months was performed. A performance ratio analysis was done in order to know how well the PV system was performing. The software HelioScope was used to simulate a model of the PV system and the results of the simulation were compared to the real energy output. A degradation analysis without irradiance data proposed by the National Renewable Energy Laboratory was implemented to compare the degradation rate between different subsystems.

    The production analysis comparison within subsystems demonstrates that some identical subsystems produce more energy than others. For the performance ratio analysis, the results showed that the PV system has a good performance ratio despite of the shading some PV modules receive. The simulation of the model in HelioScope showed some discrepancies for the winter months while for summer months it was more accurate. Finally, the degradation analysis was not possible to demonstrate actual results, but the methodology was implemented.

  • 39.
    Córdoba Candela, Jose
    Dalarna University, School of Technology and Business Studies, Energy and Environmental Technology.
    Prefeasibility Study of a Central Solar Heating Plant with Seasonal Storage in Astana2015Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The feasibility of a Central solar heating plant with seasonal storage (CSHPSS) in a new district in Astana was evaluated. A total usable footprint of 481271 m2 of low energy (passivhaus standards) multi storey apartment blocks and single family houses (15000 expected inhabitants) was studied.

    Astana is a very cold climate, with heating degree days (below 18 °C) of 5724 °C.day/year. However the solar radiation is higher than in northern Europe (where most CSHPSS are located). Space heating demand, using passivhaus standards, would be 7.2 GWh/y, DHW demand calculated was 11 GWh/y and transmission losses 2.41 GWh/y.

    Astana’s DH network was studied in order to analyze the integration of this solar thermal system within the city network. Nevertheless due to its typology (open system) and its temperature regime a newly built DH within the existing network is chosen, a secondary 60/30 °C network is considered to be appropriate. Previous plants and technologies used in central plants were reviewed in order to select the most appropriate ones.

    In the simulation, collector areas between 1.4 and 2.5 m2 per MWh heat demand and water storage volumes between 1.2 and 4.0 m3 per m2 collector area satisfy between 41 and 81 per cent of the total heat demand by solar thermal heat. Levelized cost of energy (LCOE) increases from 0.099 €/kWh to 0.107 €/KWh when increasing the solar fraction. Two systems were selected as optimum (from LCOE point of view) that gave solar fractions of at least 50 % and 80 %.

    In order to calculate feed-in tariff, Net Present Value (NPV) and Payback Time (PBT), local economic figures were chosen considering different financial considerations resulting in a discount rate of 12% and inflation of 7%. Since the heat tariff for solar thermal is not defined by law, this tariff was calculated for an expected internal rate of return of 28%. For SF=50% the investment would have a feed-in tariff of 0.184 €/kWh, a PBT=8.2 years and NPV=9.92 M€. For SF=80% the investment would have a feed-in tariff of 0.191 €/kWh, a PBT=7.75 years and NPV=16.7 M€.

  • 40.
    d’ Souza, David
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Experimental Characterisation and Modelling of a Membrane Distillation Module Coupled to aFlat Plate Solar Collector Field2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    An experimental characterisation of a pre-commercial spiral wound permeate gap membrane distillation module was carried out to test its performance at different operating conditions for the purpose of seawater desalination. The experimental setup consisted of a flat plate solar collector field indirectly coupled to the permeate gap membrane distillation module via an inertia tank. The operating parameters varied were the condenser inlet temperature (from 20 °C to 30 °C), evaporator inlet temperature (from 60 °C to 80 °C) and seawater feed flow rate (from 200 l/h to 400 l/h). Within this operational boundary, it was found that the maximum permeate/distillate flux was 4.135 l/(h∙m2) which equates to a distillate production/flow rate of close to 21.3 l/h. The maximum potential distillate production rate is expected to be significantly higher than this value though as the maximum manufacturer specified feed flow rate is 700 l/h and the maximum evaporator inlet temperature is rated at 90 °C. Both these parameters are positively related to the distillate production rate. The minimum specific thermal energy consumption was found to be 180 kWh/m3.

    A mathematical model of the overall system was developed, and experimentally validated, to mathematically describe the coupling of the membrane distillation module with a solar collector field. The effectiveness of internal heat recovery of the membrane distillation module was found to be an accurate and simple tool to evaluate the thermal energy demand of the distillation process at a given set of operation parameters. The mathematical model was used to further investigate the experimental findings and provide insights into the operational dynamics of the membrane distillation module. It was also used to determine some external conditions required for steady state operation, at a given distillation operating point, such as the minimum solar irradiation required for operation and the auxiliary cooling required in the solar collector loop for maintaining steady state conditions.

    Finally, general guidelines are provided toward better operational practices to improve the coupling of a solar thermal collector unit/field with a membrane distillation system using a storage tank or inertia tank.

     

  • 41.
    Dalenbäck, Jan-Olov
    et al.
    Svensk Solenergi.
    Ollas, Patrik
    SP Energiteknik.
    Persson, Tomas
    Dalarna University, School of Technology and Business Studies, Energy and Environmental Technology.
    Biobränsle och solvärme för 100% förnybar värmeförsörjning: Projekt nr 30688-2 - Biobränsle och solvärme2015Report (Other academic)
  • 42.
    Daroudi, Parham
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Simulation of an energy efficient single-family house in the area of Smedjebacken to meet Miljöbyggnad’s Gold House energy category requirements2018Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Since the building construction area is accounted for high share of energy usage (36 %) in

    Europe, there is high demand to pay attention to this area accurately. Sweden which is one

    of the pioneer countries in terms of building energy efficiency plans to reduce this value to

    50 % by 2050. To reduce this value there is a need to define a mandatory guideline for

    builders by the government. So national board of housing, building and planning (Boverket)

    were given responsibility to define these regulations for builders and house owners. Parallel

    with that Swedish green building council developed a certification considering the buildin

    g’s

    energy demand, indoor air climate and environmental impact of building called

    Miljöbyggnad. While all the existing and new buildings following Boverket’s regulations

    meet this certification’s lowest limitations, some ambitious

    builders tend to fulfil its highest

    level of limitations called Gold level.

    This study aimed to design a house in the area of Smedjebacken to meet Miljö

    byggnad’s

    gold house’s energy category requirements. To meet the mentioned requirements several

    parametric studies regarding insulation thickness, windows assembly, heating and ventilation

    system are done via simulation software called TRNSYS. The result of testing several

    models show that although windows assembly does not affect this building

    ’s energy demand

    very much, other parameters such as insulation

    ’s thickness and type of heating system have

    a key role.

    In addition, a parametric study regarding the impact of thermal mass on the building energy

    demand is performed. The result shows that the effect of removed massive wood is

    compensated by replaced additional mineral wool insulation.

    In conclusion it is concluded that a single family house located in a cold climate like

    Smedjebacken using

    district heating cannot meet Miljöbyggnad’s gold level criteria without

    help of heat recovery ventilation. Furthermore, building with ground source heat pump as

    its

    heating system can meet Miljöbyggnad’s principals easier than those having district

    heating. In this case building with 200 mm insulation thickness even with exhaust air

    ventilation meets certification principals easily.

  • 43.
    de Fatima Dias, Jane
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Reuse of Construction Materials2018Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The building and construction sectors are one of the main contributors to the socio-economic development of a country. Globally, these sectors generate around 5% to 10% of national employment and around 5% to 15% of a country's gross domestic product during construction, use and demolition. On the other hand, the sectors consume around 40% of world primary energy, use 30% of raw materials, generate 25% of solid waste, consume 25% of water, and use 12% of land. Furthermore, the sectors account for up to 40% of greenhouse gas (GHG) emissions, mainly from energy use during the life cycle of buildings.

    This study aims to assess the potential environmental benefits of reusing concrete and ceramic roof tile within the Swedish context in terms of their CO2 emission. Methodology used was a comparative LCA was to quantify the emissions. In order to calculate LCA, OpenLCA 1.7.0 software was used and to evaluate the emissions, LCIA method selected was ReCiPe, midpoint, Hierarchist model, climate change category expressed in GWP 100 years (in kg CO2eq). The FU of the study was a square meter of roof covering for a period of 40 years with potential to extent up to 80 years. A square meter of concrete roof tile weight 40 kg while ceramic 30 kg.

    The environment impact evaluation considered three product system, single use (cradle to grave), single use covering (cradle to user) and single reuse (user to cradle) within 40 years lifespan. In order to compare LCA of the roof tiles, two scenarios were created, Scenario 1 concrete RT in single use and single reuse whilst Scenario 2 evaluates ceramic RT. The outcomes of both scenarios were communicated through a model single family house. Dalarna’s Villa is located in Dalarna region in Sweden and a storage facility Ta Till Våra was to validate the benefits of reused materials.

    Comparative LCA revealed that concrete RT in single use released almost 80% more CO2 emissions than ceramic RT and generated 25% more disposable material by weight. The CO2 released by the single use vs. single reuse concrete RT showed higher emissions in the production of the concrete RT than the single reuse, the same occur with ceramic RT. The reuse of the tiles on the same site had an insignificant impact on the environment in both materials. The comparison shows that reuse reduces associated emissions by about 80% in both cases, reusing concrete is more beneficial, as emissions are reduced by 9.95 kg/m2 as opposed to 2.32 kg/m2 at the ceramics. This study reveals the benefit of reusing concrete and ceramic roof tile. In addition, the advantage of building a storage facility to reuse the disposable building materials, reducing the roofing materials ending at the landfill after 40 years. Furthermore, it demonstrated the reduction of CO2 emissions associated with the embodied energy.

  • 44. Dermentzis, G.
    et al.
    Ochs, F.
    Gustafsson, M.
    Calabrese, T.
    Siegele, D.
    Feist, W.
    Dipasquale, C.
    Fedrizzi, R.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    A comprehensive evaluation of a monthly-based energy auditing tool through dynamic simulations, and monitoring in a renovation case study2019In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 183, p. 713-726Article in journal (Refereed)
    Abstract [en]

    An energy auditing tool (PHPP) was evaluated against a dynamic simulation tool (TRNSYS) and used for the assessment of energy conservation measures in a demo case study. The comprehensive comparison of useful heating and cooling demands and loads included three building types (single-, multi-family house, and office), three building energy levels (before renovation and after renovation with a heating demand of 45 and 25 kWh/(m²·a)) and seven European climates. Dynamic simulation results proved PHPP (monthly energy balance) to be able to calculate heating demand and energy savings with good precision and cooling demand with acceptable precision compared to detailed numerical models (TRNSYS). The average deviation between the tools was 8% for heating and 15% for cooling (considering climates with a relevant cooling load only). The higher the thermal envelope quality was, i.e. in case of good energy standards and in cold climates, the better was the agreement. Furthermore, it was confirmed that PHPP slightly overestimates the heating and cooling loads by intention for system design. The renovation design of a real multi-family house was executed using PHPP as energy auditing tool. Several calculation stages were performed for (a) baseline, (b) design phase, and (c) verification with monitoring in order to calculate the corresponding heating demand. The PHPP model was calibrated twice, before and after the renovation. The necessity for tool calibration, especially for the baseline, was highlighted increasing the confidence with respect to a number of boundary conditions. In this study, PHPP was tested as an energy auditing tool aiming to be a versatile and less error-prone alternative to more complex simulation tools, which require much more expert knowledge and training. 

  • 45.
    Dimtsu Tamene, Hailu
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Solar Mini-grid Model Validation for Rural Electrification2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis was aimed at validating an Excel tool developed by Energicity Company. In addition, to study a commercial software that can be used to design a solar mini-grid system for the company.

    A 9.9 kW solar mini-grid in Bekwai, Ghana was used as a case study. Weather data from Meteonorm and component specification was used as input parameter for the simulation works.

    HOMER pro and PVsyst commercial software were selected to validate the Excel tool. Each software was also explained in detail.

    The validation was done by comparing input parameters and simulation results of the Excel tool with the selected commercial software. The process was divided into two main parts. The first part was, comparing the mathematical model, and the PV array electricity production of the software used as an input to the Excel tool, which was SAM, with HOMER pro and PVsyst. The second part was comparing the final simulation result of both tools, including the Excel tool.

    The comparison result shows that the difference in the mathematical model for the diffuse irradiation in each software leads to a difference in the electricity production at the PV array output. Even though the difference is not significant for a small scale mini-grid system, the difference can cause a wrong estimation for critical loads, where a higher percentage of availability is required.

    The DC losses at the PV array has a notable impact on estimating the electricity production. PVsyst considers more loss parameters than SAM and HOMER pro. As a result, the simulation result of the PVsyst shows lower electricity production at the output of the PV array compared to the others. This indicates as PVsyst is a more conservative software model.

    The loss in the battery has another significant impact on estimating the energy delivered to the load. The battery model for each tool was different. The Excel tool uses higher battery loss percentage. Due to this, the energy served to the load by the Excel tool was lower than HOMER pro and SAM. HOMER pro’s estimation of the battery loss was almost equal to the Excel tool. The battery loss estimated by PVsyst was lower than all models. However, there were uncertainties in the input parameters of the battery, because of most of the parameters provided by the battery manufacturer was not compatible with the input parameters required by PVsyst.

  • 46. Dipasquale, Chiara
    et al.
    Fedrizzi, Roberto
    Bellini, Alessandro
    Gustafsson, Marcus
    Ochs, Fabian
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Database of energy, environmental and economic indicators of renovation packages for European residential buildings2019In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 203, article id 109427Article in journal (Refereed)
    Abstract [en]

    Increasing the energy efficiency with a vast impact in the residential building stock requires retrofit solutions that can be exploited with respect to a wide range of different building typologies and climates. Several tools and methodologies are nowadays available both for the assessment of building demands and for the individuation of optimum retrofit solutions. However, they are usually either too complex to be adopted by professionals or, on the contrary, oversimplified to account for the full complexity of a deep envelope and HVAC system retrofit. In this context, this paper describes a methodology developed to generate reliable information on retrofit solutions for typical buildings in different climatic conditions. Detailed numerical models are used to simulate a number of combinations of envelope and HVAC systems retrofit measures and renewable energy integration. Energy performance results are gathered in a database that allows comparing solutions, spanning over a range of more than 250,000 combinations of building types, age of construction, climates, envelope performance levels and HVAC systems configurations. Economic feasibility is also derived for each of the combinations. In this way, the accurateness of a detailed and validated calculation is made available to assist during the decision making process, with minimum computational effort being required by professionals: the variety and density of evaluated combinations allows to easily assess the performance of a specific case by interpolating among instances previously assessed. The applicability of the results to different climates and similar building typologies is verified by a comparison of the database results with a specific case dynamic simulation.

  • 47.
    Diyad Elmi, Mohamed
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Manoharan, Lavaraj
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Optimal Grid Connected Inverter Sizing for Different Climatic Zones2019Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Grid connected inverter requires accurate and appropriate sizing which depends on the temperature, inverter operating efficiency, performance ratio, annual system yield and solar radiation characteristics. The aim of this study was to design and size for optimum sizing factor for grid connected inverter. The main component to be considered in any photovoltaic grid connected system is the inverter since the output depends on the inverter sizing ratio, therefore optimal sizing factor was designed by considering factors that affects inverter sizing such as temperature, irradiance and the location. Large and small systems of 50 kW and 5 kW respectively were considered to determine grid connected inverter sizing factors for different climates in Kenya, Sweden, and India using PVsyst simulation. Two different inverter brands of SMA and ABB with 20 kW and 25 kW rating for large system and 4.6 kW, 4 kW inverters for small system.

    PVsyst simulation result showed that different locations with different orientation angles, the optimum sizing varies hence affects the annual performance of the system. Photovoltaic system inverters are sized based on the rated power of the installed system and this can be achieved when the inverter size is either almost matching or not.

    In this case the study presents the optimal sizing factor for grid connected inverter for Mandera in Kenya, Norrköping in Sweden and Kerala in India. The determination was done through the use of designing, assessing and analyzing of the relationship between the sizing factor with performance ratio, operational efficiency and annual hourly energy yield. The unique weather profile in Kerala and in Mandera favors the adoption of solar energy technology in the location. Solar radiation for one year was used as a baseline input and the result reveals that Mandera receives yearly radiation of 2.1 MWh/m² while Kerala and Norrköping receives 2 MWh/m² and 1.1 MWh/m² respectively.

    Design simulation using PVsyst tool made it possible for the determination of the optimal sizing factor for the grid connected system. Considerations such as the losses and the variations within the specific location was done and a graph showing the relationship between the sizing factor in relation to the operational inverter efficiency as well as energy yield and performance ratio was later on compared to see the behavior of the sizing factor.

    The study concludes that operational efficiency, performance ratio and energy yield affects the array optimum sizing ratio. For the three locations, inverters (SMA and ABB) shows different variations because optimal sizing ratio depends on the location and irradiation. The results reveal that Mandera has an optimal grid connected inverter sizing of the range from 1.1 to 1.4 while in Kerala it has from 1.2 to 1.4 and Norrköping has the range from 1.1 to 1.3. Optimal sizing of grid connected inverters depends on the energy yield and the location therefore the inverter mismatch voltage and its rating values have to be considered while determining the optimal sizing factor. The 25 kW inverters in all the locations had better efficiency and sizing factor and this proves that sizing the photovoltaic inverter will give better performance and efficiency.

  • 48. Duan, Zhiyin
    et al.
    Zhan, Changhong
    Zhang, Xingxing
    De Montfort University.
    Mustafa, Mahmud
    Zhao, Xudong
    Alimohammadisagvand, Behrang
    Hasan, Ala
    Indirect evaporative cooling: Past, present and future potentials2012In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 16, no 9, p. 6823-6850Article in journal (Refereed)
    Abstract [en]

    This paper reported a review based study into the Indirect Evaporative Cooling (IEC) technology, which was undertaken from a variety of aspects including background, history, current status, concept, standardisation, system configuration, operational mode, research and industrialisation, market prospect and barriers, as well as the future focuses on R&D and commercialisation. This review work indicated that the IEC technology has potential to be an alternative to conventional mechanical vapour compression refrigeration systems to take up the air conditioning duty for buildings. Owing to the continuous progress in technology innovation, particularly the M-cycle development and associated heat and mass transfer and material optimisation, the IEC systems have obtained significantly enhanced cooling performance over those the decade ago, with the wet-bulb effectiveness of greater than 90% and energy efficiency ratio (EER) up to 80. Structure of the IEC heat and mass exchanger varied from flat-plate-stack, tube, heat pipe and potentially wave-form. Materials used for making the exchanger elements (plate/tube) included fibre sheet with the single side water proofing, aluminium plate/tube with single side wicked setting (grooved, meshed, toughed etc), and ceramic plate/tube with single side water proofing. Counter-current water flow relevant to the primary air is considered the favourite choice; good distribution of the water stream across the wet surface of the exchanger plate (tube) and adequate (matching up the evaporation) control of the water flow rate are critical to achieving the expected system performance. It was noticed that the IEC devices were always in combined operation with other cooling measures and the commonly available IEC related operational modes are (1) IEC/DEC system; (2) IEC/DEC/mechanical vapour compression system; (3) IEC/desiccant system; (4) IEC/chilled water system; and (5) IEC/heat pipe system. The future potential operational modes may also cover the IEC-inclusive fan coil units, air handle units, cooling towers, solar driven desiccant cycle, and Rankine cycle based power generation system etc. Future works on the IEC technology may focus on (1) heat exchanger structure and material; (2) water flowing, distribution and treatment; (3) incorporation of the IEC components into conventional air conditioning products to enable combined operation between the IEC and other cooling devices; (4) economic, environment and social impacts; (5) standardisation and legislation; (6) public awareness and other dissemination measures; and (7) manufacturing and commercialisation. All above addressed efforts may help increase the market ratio of the IEC to around 20% in the next 20 years, which will lead to significant saving of fossil fuel consumption and cut of carbon emission related to buildings.

  • 49.
    Elbana, Karim
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Socio-Technical Analysis for the Off-Grid PV System at Mavuno Girls’ Secondary School in Tanzania2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The aim of this study is to investigate, analyse and evaluate the installed off-grid PV system in Mavuno

    girls’ secondary school that is located in a rural area in northwest Tanzania. The original motivation behind this study was the rapid degradation of the installed battery bank within less than 3 years. The PV system was installed before the actual operation of the school, so the study aimed to answer a very pressing question which is "What is the actual load profiles in the school?". There was a high need to identify the actual school load profiles to enable several concerned social actors to evaluate the system and to decide for future extensions. Therefore, the study aimed to analyse the implementation of electricity in the school by creating actual load profiles, analysing the system performance versus the users’ needs and evaluating the sustainability and utilization of implementation.

    The study followed a multi-disciplinary approach combining the social and technical aspects of PV systems implementation

    to seek further understanding of the users’ consumption behaviours. It thus included a 1-month of field work in June 2018 during which participant observations and semi-structured interviews together with load measurements were carried out so as to create load profiles that are considering the patterns and deviations in users’ behaviours. During the field work, 2/3 of the students were in holidays so the taken measurements corresponded to the school at 30 % capacity. That is why the study also included 4 days of inverter data logging after the 1-month field work by the technical head of the school to overcome the limitations in held measurements.

    The observations showed that the actual installed system was slightly different from the documentation. In addition, the local installation practices are not fully appropriate from the technical point of view, and are affected by local social norms, as will be discussed. Besides, the participant observations and held interviews with relevant social actors showed that the daily behaviours of energy users do not exactly follow the school daily routine. Consequently, the social study was important to create actual effective load profiles. The observations and responses from interviews together with measurements were used to categorize the school loads into 29 different units. Those units can be used for current load prioritizations and for future load extrapolations. The created load profiles also represent a useful addition to load databases used by energy researchers who work on similar rural electrification projects.

    After the field work, several characteristics were calculated by Microsoft Excel such as apparent power consumptions, active power consumptions, battery bank state of charge, load power factor and PV generated energy. The characteristics were used in calculations evaluating the energy balance in the system. The results of held calculations showed that lighting during dark hours accounted for on around 78 % of the logged daily apparent energy use, as it has a low a low average power factor of 0.28. It also showed that some loads if time-bounded, they will significantly decrease the daily energy consumption. The calculations were also used to run PVSyst simulations to evaluate the system sizing which resulted in the recommendation that either the array size should be doubled, or the apparent energy consumption should be decreased to half.

    The study included suggestions for possible improvements such as decreasing the reactive consumed energy by either replacing the currently used light bulbs with ones that have higher power factor (

    ≥0.8 for example) or by installing a capacitive compensation for power factor correction. In addition, it was recommended to quantify the school loads according to their priority or importance and to regulate observed time-unbounded loads such as "pumping water" and "ironing". Lastly, the study discussed how generated electricity is utilized in the school and what opportunities for women empowerment have become potentially possible with the provision of electricity.

  • 50.
    Elemam, Aboubker
    Dalarna University, School of Technology and Business Studies, Mechanical Engineering.
    Development of a ESES Solar Thermal Lab on Full Scale System2011Independent thesis Advanced level (degree of Master (One Year)), 12 credits / 18 HE creditsStudent thesis
    Abstract [en]

    The main aim of this project is to develop an ESES lab on a full scale system. The solar combisystem used is available most of the time and is only used twice a year to carry out some technical courses. At the moment, there are no other laboratories about combisystems. The experiments were designed in a way to use the system to the most in order to help the students apply the theoretical knowledge in the solar thermal course as well as make them more familiar with solar systems components. The method adopted to reach this aim is to carry out several test sequences on the system, in order to help formulating at the end some educating experiments. A few tests were carried out at the beginning of the project just for the sake of understanding the system and figuring out if any additional measuring equipment is required. The level of these tests sequences was varying from a simple energy draw off or collector loop controller respond tests to more complicated tests, such as the use of the ‘collector’ heater to simulate the solar collector effect on the system. The tests results were compared and verified with the theoretical data wherever relevant. The results of the experiment about the use of the ‘collector’ heater instead of the collector were positively acceptable. Finally, the Lab guide was developed based on the results of these experiments and also the experience gotten while conducting them. The lab work covers the theories related to solar systems in general and combisystems in particular. 

1234567 1 - 50 of 303
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • chicago-author-date
  • chicago-note-bibliography
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf