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  • 151. Luo, H.
    et al.
    Liang, X.
    Lu, J.
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Applicability analysis of insulation in different climate zones of China2017In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 142, p. 1835-1841Article in journal (Refereed)
    Abstract [en]

    In this paper we evaluated the applicability of the widely-used passive design strategy i.e., insulation, in three typical climate zones of China. Software IES VE was used for modelling and simulation of performance of insulation in a residential house. The practical behavior patterns of Chinese family from survey were utilized for analyzing the thermal characteristics of the house. Four parameters of the results were selected for analyzing the performance of insulation in three cities of China. The conditions varying in time periods and locations were compared on the basis of the simulation.

  • 152.
    Luthander, Rasmus
    et al.
    Uppsala universitet, Fasta tillståndets fysik.
    Psimopoulos, Emmanouil
    Dalarna University, School of Technology and Business Studies, Energy Technology. Uppsala universitet, Fasta tillståndets fysik.
    Widén, Joakim
    Uppsala universitet, Fasta tillståndets fysik.
    Demand Side Management Using PV, Heat Pumps and Batteries: Effects on Community and Building Level2017In: Proceedings of the 33rd European Photovoltaic Solar Energy Conference, 2017Conference paper (Refereed)
    Abstract [en]

    This study examines how the energy management optimization on household level affects the maximum power flow in a community of houses and the contribution to load smoothening in the community. A detailed model of a single-family house with exhaust air heat pump and photovoltaic system is used in combination with high-resolution weather, electricity use and hot water use data. All five houses in the community are identical but the occupancy of the residents and their use of electric appliances and hot water differ. Results show no reduction of the maximum power delivered to the grid if the houses are operated to optimize the individual self-consumption and self-sufficiency. The highest aggregated power from the grid for the whole community occurred when the heat pumps were controlled by the PV electricity production but without any battery storage. This case also resulted in least smoothing of the aggregated household loads in the community. The conclusion of the study is that energy optimization for individual households in a community do not have to result in a reduction of the aggregated load and power production.

  • 153.
    Magnusson, Benny
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Ekerind, Mattias
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    FTX-system i flerbostadshus2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of the report is to investigate potential energy savings when installing FTX systems in multi-family houses. Three common types of heat exchangers are compared to each other: rotary, counter current and cross heat exchangers. The purpose is to see how much the different systems reduce the specific energy use of the building. The house in the study is a typical multi-family house from the 70's located in Borlänge. Exhaust air ventilation is installed, and the building shell is of expected standard of an older apartment block. The specific energy use was calculated at 156 kWh/m

    2 year, far from BBR’s requirements for new construction or major renovations.

    No new measurements have been made on site in the study and the focus lies in processing and evaluating secondary data. Information about the FTX systems was extracted from quotations from selected suppliers. Data regarding the building was derived from blueprints while usage data was collected from the SVEBY project, which compiles surveys and measurements of residents’ habits.

    It was found that the installation of FTX systems, regardless of type, reduced the specific energy consumption by about 30%, down to around 110 kWh / m

    2 year. Only installation of an FTX system would not suffice to meet current BBR requirements. Furthermore, it was found that a theoretical renovation of the building shell according to BBR´s new building regulations had an equivalent result and reduced the building's specific energy consumption by 25%. As a combined measure, the installation of an FTX system and building shell renovation according to BBR´s new building regulations would make it possible to meet BBR’s requirements for specific energy use.

    The negligible difference in performance of the various FTX systems can, to some extent, be explained by the lack of data available for the study. Nevertheless, the choice of FTX system should largely be based on other criteria such as cost of assembly, installation and maintenance as well as comfort in terms of noise level and filtered air pollution.

  • 154.
    Majli, Nadia
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Reverse Osmosis Desalination in Morocco; Preliminary Techno-economic Assessment of Autonomous Grid Connected and Off-grid Photovoltaic Systems2018Independent thesis Advanced level (degree of Master (Two Years)), 12 credits / 18 HE creditsStudent thesis
    Abstract [en]

    Reverse osmosis desalination powered by a photovoltaic system can potentially break the dependence of conventional desalination. This can reduce operation costs of the system as well as improve environmental sustainability. This thesis project presents a study on grid connected and stand-alone photovoltaic systems to provide the required electricity for

    providing fresh water to a golf course located near a luxury hotel resort in Agadir, Morocco. This site requires a high quantity of fresh water for grass spraying systems. The design steps of the suggested system are carried out such that the site radiation data and two different scenarios for the electrical load distribution have been analyzed in the considered site are taken into account during the design simulation. Also, a techno-economic analysis is conducted to assess the economic viability of the system.

    The main simulation tool to be used in this thesis is HOMER (Hybrid Optimization Modeling Electric Renewables) developed by the National Renewable Energy Laboratory (NREL) in the United States of America. HOMER is a simulation tool designed to optimize the size of energy systems for defined boundary conditions. The optimization is based on economic figures such as the Net Present Cost (NPC). This tool helps to find the least cost combination of components. HOMER can be applied to a number of system designs such as on grid, off-grid. A sensitivity analysis of different parameters have also been studied such as PV capital cost per kW, and finally the escalation rate of diesel price.

    The main conclusion, that the capital cost of the photovoltaic system with the reverse osmosis desalination unit is at the moment high. This case study becomes competitive with the other hybrid alternativ.

  • 155. Malmqvist, C.
    et al.
    Wallin, Elisabeth
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Lindström, Anders
    Dalarna University, School of Technology and Business Studies, Forest and Wood Technology.
    Säll, H.
    Differences in bud burst timing and bud freezing tolerance among interior and coastal seed sources of Douglas fir2017In: Trees, ISSN 0931-1890, E-ISSN 1432-2285, Vol. 31, no 6, p. 1987-1998Article in journal (Refereed)
    Abstract [en]

    The need for species that will grow well through ongoing climate change has increased the interest in Douglas fir [Pseudotsuga menziesii (Mirb.) Franco] in Sweden. One of the most common problems seen in plantations of Douglas fir seedlings is damage caused by late spring frost, known to be highly correlated with the timing of bud burst. The objective of this study was to investigate spring-related bud development under Nordic conditions of seven Douglas fir provenances and to compare data with a local provenance of Norway spruce (Picea abies (L.) Karst). Results from a field trial and a greenhouse-based study were compared. The interior Douglas fir provenances exhibited an earlier bud burst than coastal provenances, both in the greenhouse and in the field trial. When comparing differences within the groups of interior and coastal Douglas fir provenances, no differences could be found. The local Norway spruce, only grown in the greenhouse, showed an intermediate bud development profile similar to the interior Douglas fir provenance Three Valley. We therefore suggest that Three Valley could be planted at the same locations as the investigated local provenance of Norway spruce in mid-Sweden. To avoid spring frost damage the Douglas fir seedlings need to be frozen stored and planted late in spring. Planting under shelterwood can also help protect the seedlings from spring frost damages. As similar results for bud development patterns of Douglas fir and Norway spruce provenances were obtained from the greenhouse and field trials, greenhouse tests could facilitate selection of provenances.

  • 156.
    Manhal, Ali
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    M. Ali, Tammam
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Solar Tent: A Photovoltaic Generator Model for a Flexible Fabric with Inbuilt Cells2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Natural disasters and conflicts in many different parts of the world force thousands of people to get displaced from their homes and live in refugee camps temporarily or permanently. For refugee families, lack of energy access has great impact on their lives.

    Tarpon Solar Company has developed a solar tent which is a combination of laminated cloth and flexible solar cells. In addition to producing renewable electricity, it can create a comfortable outdoor shelter from sun, rain and wind.

     

    The aims of this study were to define and size the solar system of the tent in both AC and DC systems and optimize the tent to work in different locations around the world. Besides designing a monitoring system for the solar tent to evaluate the performance. In addition, defining the social aspect and the consumer behavior for a better solar tent future design. As a case study, Tarpon AC solar tent in Glava, Sweden has been installed to cover the basic needs of the tent users. To understand the solar tent performance in different weather zones, 4 different locations were suggested. A monitor system was designed to monitor the tent solar system performance. The simulation software PVsyst was used to size the PV system in the different locations with different solar data.

     

    The PVsyst simulation results showed that the current Tarpon solar tent with 32 photovoltaic modules is extremely oversized to cover the basic needs loads (Lighting, mobile charging and ventilation) in the emergency cases.

     

    The current Tarpon solar tent has a standard number of photovoltaic modules integrated in the tent fabric while the photovoltaic modules number should vary from one location to another according to the weather data and solar irradiation. In this case the current Tarpon solar system used in Glava, Sweden can be optimized by decreasing the number of photovoltaic modules to only 6 photovoltaic modules instead of 32 modules.

     

    The study also shows that the features of the off-grid system components (battery and charge controller) are different from one location to another according to the criteria of selection.

     

    This study concludes that for the temporary short-term emergency use of the tent where only basic needs loads are needed, DC system is better than AC system in terms of energy efficiency, system size and cost in the different proposed locations. While AC system is better when using the tent for prolonged time in terms of user flexibility and ability to extend the system. Understanding the consumer behavior and the goal of the tent whether to be used for an emergency short term shelter or a permanent shelter for a prolonged time are important factors for a better solar tent design.

  • 157.
    Mattsson, Anders
    et al.
    Dalarna University, School of Technology and Business Studies, Forest and Wood Technology.
    Hernandez Velasco, Marco
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Rusu, Cristina
    Acreo Swedish ICT AB.
    Pietrzak, Malgorzata
    Azorina S.A.
    Ferreira, Raquel
    Azorina S.A.
    Radoglou, Kalliopi
    Democritus University of Thrace.
    Smirnakou, Sonia
    Democritus University of Thrace.
    Bantis, Filippos
    Democritus University of Thrace.
    Fulgaro, Nicoletta
    Università degli Studi dell'Insubria.
    Kotilainen, Titta
    Valoya OY.
    ZEPHYR Project – Deliverable D7.6: Articles and peer-reviewed papers2015Report (Other (popular science, discussion, etc.))
  • 158.
    Mazraeh, Hifa
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Abdullahi, Abdiaziz
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Värmeåtervinning ur spillvatten för flerbostadshus: Kornstigen 25 i Borlänge2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this work is to compile knowledge of waste water recovery systems in multi-family houses from literature, previous studies and relevant actors on the subject area. The purpose is also to make temperature measurements in a multi-family house in Borlänge to calculate and analyze the energy saving potential of the Ekoflow heat exchanger from Isaksson Rostfria AB.

    Ekoflow is a waste water heat exchanger that recycles heat energy from wastewater. Through wastewater heat exchanger, the waste water flows from the drain and the cold water in the countercurrent direction. Ekoflow has been installed in some bath houses and hotels and showed good recovery rates in these areas.

    It is a little difficult to find a temperature meter on the market that can measure and store the measured values of a vertical drainage stream. Therefore, produced own temperature meter, which was used to collect measurement data for analysis and calculation of the results.

    Application of the technology in the reference building adds some problems. One problem is that both gray and black water pass through the same pipe which reduces the temperature of the waste water. The second problem is that the building does not have a common connection point to the municipal sewers, which means that a heat exchanger will be needed for each main line.

    Energy consumption in multi-family houses varies depending on the living space and number of residents in the house. The number of residents in the reference building is not known but the temperature and water flow and spill water temperature measurements showed that the building has high hot water consumption. Energy saving depends on several parameters such as incoming cold and waste water temperature to waste water heat exchanger and the length of heat exchanger. The energy savings for three different lengths of the Ekoflow heat exchanger were calculated and a 48-meter heat exchanger showed energy savings of approximately 40 MWh / year, which is profitable from the energy saving perspective.

  • 159. Menegon, D.
    et al.
    Persson, Tomas
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Haberl, R.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Haller, M.
    Direct characterisation of the annual performance of solar thermal and heat pump systems using a six-day whole system test2020In: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 146, p. 1337-1353Article in journal (Refereed)
  • 160.
    Menthon, Maxence
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Van Migom, Léa
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Reducing energy consumption of refrigerators byusing the outside temperature2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Nowadays, many electrical appliances are used daily. The refrigerator is one of them.

    Consequently, by affecting the energy used by the refrigerator, a huge amount of energy,

    greenhouse gases (GHG) emissions and money can be saved. It is what this thesis tries to do

    by applying a concept: using the cold from outside. Indeed, this report exposes the process to

    answer the following question:

    How much energy, GHG emissions and money can be saved by using the cold from

    outside on the refrigerating appliances?

    To do so, measurements have been done on a refrigerator placed in a climate chamber. The

    experiment procedure is inspired by the Swedish standard of energy consumption testing in

    order to have the most relevant results as possible. The results of the measures were then used

    to create a mathematical modelling. And finally, by applying the modelling at different

    climate of the world represented by chosen cities, calculations were made to estimate the

    energy, GHG emissions and money savings which can be done thanks to this concept.

  • 161.
    Molin, Elin
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Stridh, B.
    Molin, A.
    Wäckelgård, Ewa
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Experimental yield study of bifacial PV modules in Nordic conditions2018In: IEEE Journal of Photovoltaics, ISSN 2156-3381, E-ISSN 2156-3403, Vol. 8, no 6, p. 1457-1463Article in journal (Refereed)
    Abstract [en]

    This study reports on the first full-year field study in Sweden using bifacial photovoltaic modules. The two test sites are located on flat roofs with a low albedo of 0.05 in Linköping (58 °N) and were studied from December 2016 to November 2017. Site 1 has monofacial and bifacial modules with a 40° tilt facing south, which is optimal for annual energy yield for monofacial modules at this location. Site 2 has monofacial 40° tilt south-facing modules and bifacial vertical east–west orientated modules. The annual bifacial energy gain (BG E ) was 5% at site 1 and 1% at site 2 for albedo 0.05. The difference in power temperature coefficients between bifacial and monofacial modules was estimated to influence BG E by +0.4 and +0.1 percentage points on site 1 and 2, respectively. A higher albedo could be investigated on a sunny day with fresh snow for the bifacial east–west modules. The specific yield was 7.57 kWh/kW p , which was a yield increase of 48% compared with tar paper at similar solar conditions.

  • 162.
    Morales-Pallares, Marcos
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Long Term Sustainability of Standalone PV Systems for Community Services: Case Studies from Rwanda2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis was developed with a twofold aim in mind. In first place, to study some of the components that are required to achieve long term sustainability of standalone PV systems for community services. This means, to put in place the necessary ingredients to ensure that standalone PV systems that power schools, health centers or administration offices, among other public institutions, are able to last for their typical life time (20-25 years).

    In particular, the focus of this theoretical part of the thesis is mainly set on both the technical and socio-technical dimensions of long term sustainability. As part of the first one, the study delves into aspects related to PV system design and quality in installations, sustainable system use and operation, as well as maintenance theory. As part of the socio-technical dimension, research in the literature has been done mainly about those social concepts related to the community surrounding a PV system, aspects related to system operation from a user’s perspective, as well as maintenance seen from a socio-technical point of view. Complementarily to the previous two, other dimensions such as the financial, governmental, environmental and related to project management are also introduced.

    The second part of this thesis is based on work done during a one month trip to Rwanda. During this time three main case studies were developed around two schools and one health center, in order to assess the degree of fulfilment of the different dimensions of long-term sustainability in these sites, setting most of the efforts on both the technical and the socio-technical dimensions. Additionally, three complementary (and shorter) visits to two administration offices and an additional school also took place. These visits plus some interviews to several Rwandan companies completed the picture of long-term sustainability of standalone PV systems in the Rwandan context.

    Although the components and the installation of standalone PV systems in recent national Rwandan programs were of high quality, there was generally a lack of adequate direct and indirect lightning protections, in spite of the fact that Rwanda is one of the places with highest keraunic levels in the world. In some cases, previous systems had poor designs, used low quality wiring or installed low quality batteries, not in compliance with international standards. In terms of maintenance and component replacements, these elements were almost never taken into account as part of any original project plan, including financial and human resources. However, although maintenance structures only started to be defined in national programs after system installation, they all lacked the actors and instruments to properly trace quality in maintenance.

    In socio-technical terms, efforts to engage or transfer system operation and energy efficiency knowledge, in the form of trainings for end-users, did not seem to be sufficient. Therefore, some sites experimented a notable load increase or a load shift. In most situations, energy consumption could be optimized, either by using energy efficient appliances (e.g. namely thin clients, energy efficient fridges) or by optimizing the frequency and total time of their use (i.e. autoclaves in health centers). Simple but yet effective operation strategies could also be easily adopted in order to adequate energy use to energy generation, as per the examples included in this thesis. Last but not least, remote monitoring solutions should be considered in the future as means to improve operation and maintenance, especially in wide national projects.

  • 163.
    Moretti, Sebastián
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Simwinga, Abiya
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Economic and Technical Analysis of Integration of PV into the Existing Diesel Power Station in Shang’ombo, Zambia2017Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The main objective of this study was to carry out an economical and technical analysis of integrating PV into an existing 320 kW diesel power plant in Shang’ombo township in the western province of Zambia. Additionally, the study evaluates the best feasible solution by analyzing different hybrid combinations and configurations whilst taking into account the least Levelized Cost of Electricity (LCOE) and the Net Present Cost (NPC) with regard to the Life Cycle Cost of the project. Hybrid Optimization of Multiple Electric Renewables- (HOMER) software was used for modelling and simulation of five different off-grid solutions. CASE A was for the current system (100 % diesel generated power plant), CASE B: current system and PV, CASE C: Current system, PV and battery, CASE D: Current system, PV, battery and an additional small generator and CASE E: 100% PV and battery.

    The results show that the current system (100 % diesel generator system) is not economically sustainable as it has a very high LCOE of $0.50/kWh due to high cost of diesel and high costs of operation and maintenance of diesel generator sets. On the other hand, a system with 100 % PV with batteries gave the lowest LCOE of $ 0.31/kWh, as it had the lowest operation and maintenance costs and, additionally, zero carbon emissions. Overall, the NPC of the system with 100 % PV with batteries was 1.7 times lower than the current diesel system. However, if the utility company, Zambia Electricity Supply Corporation (ZESCO), would prefer to use the existing diesel generators for the PV/Diesel hybrid system, then CASE C would be the best solution. This hybrid configuration achieves 87 % solar fraction with LCOE of $ 0.39/kWh.

    Lastly, the results generally showed that the initial capital cost of solar energy projects was relatively higher as compared to the equivalent diesel based plants. However, with the continued down ward trend in the price of PV per kWp, solar is the best solution to bridge the current energy deficit that Zambia is currently facing. Additionally, solar solutions answers the worlds cry for clean energy which is environmentally friendly and reduces on the impacts of global warming.

  • 164.
    Mugisha, Jean Claude
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    A study on Auxiliary Battery Energy Storage to Mitigate PV Output Power Fluctuations: Case Study: 8.5 MW Agahozo Shalom Youth Village (ASYV) PV Power Plant in Rwanda2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Solar energy is experiencing a rapid growth worldwide and it is a promising technology to play a vital role in future power systems. However, the natural intermittent of solar energy resources affect the quality of the output power from a solar system putting its dispatchability in question. Battery Energy Storage System (BESS) is among the solutions to suppress PV power fluctuations and allow smooth PV power production as result. In this work, BESS was modelled, integrated and simulated for Agahozo Shalom Youth Village (ASYV) PV Power Plant located in Rwanda. MATLAB/Simulink was used as modelling and simulation tool and Excel was used in data analysis. For ease of work, one of eight PV arrays at the power plant was considered and the results were scaled up to the entire power plant afterwards.

    Annual data for year 2017 was analysed and the worst-case scenario which is the day with highest irradiance variation was found. Both PV power and ambient temperature data for this day were used as input to the model. Four smoothing approaches namely Low Pass Filter (LPF), Simple Moving Average (SMA), Exponential Moving Average (EMA) and Ramp Rate Control (RRC) were investigated in detail, applied to the model and compared in terms of performance and battery size that each approach would require. The degree to which power output needs to be smoothed can vary based on regulatory requirements and the technical conditions of the power grid. For this reason, three Ramp Rate Limits (RRLs) namely ±10 %, ±20 % and ±30 % of the rated PV array power per minute were applied in smoothing algorithms to see how large the battery storage would be if Rwandan grid operator was to impose one of the aforesaid RRLs.

    The results showed that all smoothing methods managed to smoothen out PV array power at all RRLs as intended. The difference occurred in performance of smoothing methods and battery size in terms of power and energy that each method required. In all cases, it was noticed that both LPF and EMA displayed almost similar results which made it difficult to make a clear distinction between the two. However, in their slight difference, EMA required a slightly smaller battery size. The memory effect of SMA was noticed and this method was requiring bigger battery size at all RRLs. The RRC performance was better especially at ±10 % RRL compared to other three methods. The particularity of RRC was that it only allows the battery to respond when needed and the battery charges or discharges the exact amount of power needed. This was different from the other three smoothing methods. They were always allowing the battery to respond even when the present power ramp is within the set RRL resulting in high charging/discharging cycles which causes cyclic degradation of the battery. In addition, these methods over-smoothed the PV array power where more than needed power could be absorbed or delivered by the battery resulting in unnecessary bigger battery size.

    Some of downsides of RRC method were that it requires bigger battery size in terms of energy and it could be more sensitive to the uncertainty associated with PV array power measurement compared to other methods. Nonetheless, its battery size in terms of power requirement was less than other methods since it does not over-smooth the PV array power. Since RRC and EMA methods were requiring less battery power and less battery energy at all RRLs respectively, both methods were chosen while scaling up the results to the entire power plant. Using EMA smoothing methods over RRC at ±10 % RRL could results in saving $113 thousand of battery capital cost. However, at ±20 % and ±30 % RRL, the RRC method was found to be the best option since it needs less capital cost than EMA smoothing approach.

  • 165.
    Myhren, Jonn Are
    et al.
    Dalarna University, School of Technology and Business Studies, Construction.
    Heier, Johan
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Hugosson, Mårten
    Dalarna University, School of Technology and Business Studies, Business Administration and Management.
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    The perception of Swedish housing owner’s on the strategies to increase the rate of energy efficient refurbishment of multi-family buildings2018In: Intelligent Buildings International, ISSN 1750-8975, E-ISSN 1756-6932Article in journal (Refereed)
    Abstract [en]

    Improving the energy performance of existing buildings is crucial for reaching both EU and national climate and energy targets. The main objective of this study was to map challenges that Swedish housing owners perceive when making energy-efficiency refurbishments. A secondary objective was to compare how well these challenges relate to national strategies. The study applied a combined methods approach with audience response meters and in-depth qualitative semi-structured interviews. The housing owners express the view that they have sufficient knowledge of national ambitions to improve the energy performance of buildings and welcome the new building regulations. Despite this supposed knowledge and the current economic situation with beneficial loans, the refurbishment rate still remains low. The housing owners explain that they are concerned about the ‘performance gap’ and request more accurate energy performance predictions. They are also waiting for proof that all sustainability goals can be reached in reality. Probably, too few projects fulfilling ambitions in all categories: economically, socially and energy-wise have been followed up and demonstrated nationally. The new national information centre on refurbishment of buildings may help to spread information about such projects, raise awareness and thus increase the refurbishment rate.

  • 166.
    Myhren, Jonn Are
    et al.
    Dalarna University, School of Technology and Business Studies, Construction.
    Olofsson, Thomas
    Dalarna University, School of Technology and Business Studies, Construction.
    Bergdahl, Martin
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Lågtemperaturuppvärmning med tilluftsradiatorer och värmeåtervinning i frånluft: en varsam renovering av flerbostadshus för energieffektivisering2014Report (Other academic)
    Abstract [sv]

    För att nå reella sänkningar av energianvändningen i hela byggnadsbeståndet krävs tillgång till kostnadseffektiva renoveringspaket med energieffektiva systemlösningar där samspel mellan installationssystem och byggnad beaktas.

    Denna förstudie belyser möjligheter med alternativa renoveringspaket med lågtemperatur-tilluftsradiatorer och värmeåtervinning i frånluften (FX). Systemkombinationer och jämförelser har gjorts med mera etablerade lösningar med traditionella radiatorer, balanserad mekanisk ventilation (FTX) och solvärme. Mindre prövade lösningar såsom frånluftsmoduler (VBX) kopplat till befintliga värmepumpar och behovsstyrd ventilation undersöktes också.

    Energianvändning och kostnadseffektivitet med de undersökta åtgärdspaketen prövades för två äldre bostadshus med vardera specifika restriktioner: den ena inom fjärrvärmenätet och det andra ett K-märkt hus utanför fjärrvärmenätet. Samtidigt reflekterades det över vilka tekniska lösningar som samtidigt är gynnsammast ur hållbarhetssynpunkt. För flertalet befintliga byggnader behöver såväl metoder som komponenter utvecklas på ett varsamt sätt som uppfyller båda ägarens krav som övergripande mål baserat på systemförutsättning och kostnadseffektivitet.

    Förstudien visar att:

     lågtemperatur-tilluftsradiatorer är en systemkomponent som möjliggör ökad komfort via förvärmning och filtrering av inkommande ventilationsluft, effektivare värmeproduktion och minskning av värmeförluster i distribution av varmvatten. Renovering med installation av FX-system i kombination med lågtemperatur-tilluftradiatorer är ett alternativ till FTX system som begränsar byggåtgärderna i byggnaden och ger lägre livscykelkostnad

     Byggnadsskalets täthet blir avgörande för energinyttan båda med FX- och FTX-system. Förstudien visar att FX-system är fördelaktig i byggnader med dålig lufttäthet

     I byggnader med befintligt frånluftssystem kan behovsstyrning av ventilationen vara ett enkelt och kostnadseffektivt sätt att sänka ventilationsförlusterna och spara energi som alternativ till att installera återvinningssystem

    Förstudien visar klart att energieffektiv renovering kan åstadkommas med val av varsamma metoder som också åstadkommer ökad komfort och systemnytta, utanför såväl som inom fjärrvärmenätet. Samtidigt kan ägarens krav på kostandsnytta nås och byggnaders bevarandekrav uppfyllas.

    Nu krävs det demonstrationsprojekt för att inte minst sprida kunskap i branschen men också applicering på större bostadsområden.

  • 167.
    Niklasson, Fredrik
    et al.
    SP Energiteknik, Borås.
    Persson, Tomas
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Marknadspotential för bio- och solvärmesystem2008Report (Other academic)
    Abstract [sv]

    I denna rapport analyseras marknaden för kombinerade sol- och pelletsystem, medfokus på småhus. Syftet är att presentera antalet objekt inom olika kategorier av husoch värmesystem som kan vara intressanta för konvertering till bio-sol system samtatt ge en uppskattning av årliga uppvärmningsbehov inom respektive kategori.

    Energistatistik från Statistiska centralbyrån (SCB) har använts i kombination medtidigare studier av byggnadsbestånd och byggnadsutformning. Dessutom harinformation inhämtats från olika branschorganisationer.

    Från föreliggande genomgång står det klart att den största potentialen för bio-solsystem finns på villamarknaden både för helt nya system och för kompletteringar tillbefintliga system. År 2006 fanns det 775 000 småhus med vattenburen värme varav ca183 000 hade vattenburen el. Uppskattningsvis fanns 109 000 småhus med bådevattenburen el och lokaleldstad för biobränsle och ca 118 000 hus bedöms ha haftmöjlighet till oljeeldning (denna grupp har troligtvis minskat ytterligare efter 2006).Bland de elvärmda husen finns också ca 102 000 småhus med frånluftvärmepumpareller luft/vattenvärmepumpar. 365 000 av husen hade en biobränslepanna. Därtillkommer 504 000 hus med direktelvärme, varav ca 292 000 med lokaleldstad.

    Medelförbrukningen för uppvärmning och varmvatten för hus som enbart värms medolja är ca 27 MWh/år, medan motsvarande värde för småhus med vattenburen el är ca15 MWh/år. Småhusen med direktel använder ca 12 MWh/år för uppvärmning ochvarmvatten. Det betyder att ekonomin blir betydligt sämre vid konvertering avelvärmda hus jämfört med oljekonvertering, eftersom energibehovet är lägre samt attinstallationskostnaden kan vara högre.

    En uppskattning av antalet komponenter som inom 10 år kan komma att installeras idessa hus är 213 000 solfångare, 108 000 ackumulatortankar, 106 000 skorstenar,84 000 luftburna pelletkaminer och varmvattenberedare, 40 000 vattenmantladekaminer och 28 000 pannrumspannor. Dessutom tillkommer en utbytesmarknad,kanske speciellt bland husen med biobränslepanna, där gamla pannor byts ut elleräldre människor som tidigare orkat elda med ved till slut byter till pelleteldning.

    Av nybyggda villor uppvärms ca 30 % med el i kombination med biobränsle(troligtvis lokaleldstad) och ungefär lika stor andel värms med enbart vattenburen el(antagligen ofta kompletterat med frånluftvärmepump). Det borde vara av intresse attredan vid nybyggnationen få in integrerade solfångare och pelleteldning i störreutsträckning i nya hus och det kan bli lättare efter att byggreglerna ändras den 1:ajanuari 2010 med en skärpning av kraven för nybyggda hus som använder el föruppvärmning, alltså även el till värmepumpar.

    Potentialen för bio-solsystem till flerbostadshus och lokaler är begränsad då 86 % avflerbostadshusen och nära 70 % av lokalerna värms med fjärrvärme. Det fanns år2006 ca 6200 lokaler med oljeeldning, 4600 lokaler med vattenburen elvärme och5700 lokaler med direktverkande elvärme. I lokalerna som redovisas av SCB ingårinte tillverkande industri. För lägenheter i flerbostadshus gäller att ca 42 000lägenheter värms med enbart olja, 44 000 lägenheter med olja och värmepump,48 000 lägenheter använder direktel och 31 000 lägenheter vattenburen el.

  • 168.
    Niklasson, Fredrik
    et al.
    SP Energiteknik, Borås.
    Persson, Tomas
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Marknadspotential för sol- och biovärmesystem2010Report (Other academic)
    Abstract [sv]

    I denna rapport analyseras marknaden för kombinerade sol- och pelletsystem, med fokus påsmåhus. Syftet är att presentera antalet objekt inom olika kategorier av hus och värmesystemsom kan vara intressanta för konvertering till bio-sol system samt att ge en uppskattning avårliga uppvärmningsbehov inom respektive kategori.

    Energistatistik från Statistiska centralbyrån (SCB) har använts i kombination med tidigarestudier av byggnadsbestånd och byggnadsutformning. Dessutom har information inhämtatsfrån olika branschorganisationer.

    Från föreliggande genomgång står det klart att den största potentialen för bio-sol systemfinns på villamarknaden både för helt nya system och för kompletteringar till befintliga system.År 2006 fanns det 775 000 småhus med vattenburen värme varav ca 183 000 hade vattenburenel. Uppskattningsvis fanns 109 000 småhus med både vattenburen el och lokaleldstadför biobränsle och ca 118 000 hus bedöms ha haft möjlighet till oljeeldning (dennagrupp har troligtvis minskat ytterligare efter 2006). Bland de elvärmda husen finns också ca102 000 småhus med frånluftvärmepumpar eller luft/vattenvärmepumpar. 365 000 av husenhade en biobränslepanna. Därtill kommer 504 000 hus med direktelvärme, varav ca 292 000med lokaleldstad.

    Medelförbrukningen för uppvärmning och varmvatten för hus som enbart värms med olja ärca 27 MWh/år, medan motsvarande värde för småhus med vattenburen el är ca 15 MWh/år.Småhusen med direktel använder ca 12 MWh/år för uppvärmning och varmvatten. Det betyderatt ekonomin blir betydligt sämre vid konvertering av elvärmda hus jämfört med oljekonvertering,eftersom energibehovet är lägre samt att installationskostnaden kan vara högre.En uppskattning av antalet komponenter som inom 10 år kan komma att installeras i dessahus är 213 000 solfångare, 108 000 ackumulatortankar, 106 000 skorstenar, 84 000 luftburnapelletkaminer och varmvattenberedare, 40 000 vattenmantlade kaminer och 28 000 pannrumspannor.Dessutom tillkommer en utbytesmarknad, kanske speciellt bland husen medbiobränslepanna, där gamla pannor byts ut eller äldre människor som tidigare orkat elda medved till slut byter till pelleteldning.

    Av nybyggda villor uppvärms ca 30 % med el i kombination med biobränsle (troligtvis lokaleldstad)och ungefär lika stor andel värms med enbart vattenburen el (antagligen oftakompletterat med frånluftvärmepump). Det borde vara av intresse att redan vid nybyggnationenfå in integrerade solfångare och pelleteldning i större utsträckning i nya hus och det kanbli lättare efter att byggreglerna ändras den 1:a januari 2010 med en skärpning av kraven förnybyggda hus som använder el för uppvärmning, alltså även el till värmepumpar.

    Potentialen för bio-solsystem till flerbostadshus och lokaler är begränsad då 86 % av flerbostadshusenoch nära 70 % av lokalerna värms med fjärrvärme. Det fanns år 2006 ca 6200lokaler med oljeeldning, 4600 lokaler med vattenburen elvärme och 5700 lokaler med direktverkandeelvärme. I lokalerna som redovisas av SCB ingår inte tillverkande industri. Förlägenheter i flerbostadshus gäller att ca 42 000 lägenheter värms med enbart olja, 44 000lägenheter med olja och värmepump, 48 000 lägenheter använder direktel och 31 000 lägenhetervattenburen el.

  • 169.
    Nouvel, Romain
    et al.
    ZAFH.
    Cotrado, Mariela
    ZAFH.
    Bertesina, Diego
    Manens.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Birchal, Sarah
    Fedrizzi, Roberto
    D4.2 Assessed Standardised Energy Generation and Energy Distribution Packages2016Report (Other academic)
  • 170.
    Nyirenda, Elvis
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Conjunctive Operation of Hydro and Solar PV Power with Pumped Storage at Kafue Gorge Power Station (Zambia)2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This report covers the work carried out to redesign the two existing conventional hydro power stations in Zambia on the Kafue river into the pumped storage facility with solar photovoltaic power so that security of supply and water conservation is achieved to reduce the power deficits during the dry and drought periods. The two stations are Kafue gorge upper power station (KGUPS) and Kafue gorge lower power station (KGLPS) with an installed capacity of 990 MW and 750 MW respectively. These two stations are dammed hydro power station with the reservoirs size of 785 106 m3 and 80 106 m3 respectively and situated on the 9000 hectares of land with the net head of 400 m. The two plants are situated 15 kilometres apart and the water inflow in the KGUPS is dependent on the water release from the holding dam Ithezi- thezi (ITT dam) situated 220 kilometres from the KGUPS dam. The work covered the sizing of the storage dams and determining the autonomy days needed in order to keep the station (KGUPS) running with minimal impact on power blackouts which were calculated at 5 days considering the size of the dam and the available energy. The financial calculation for the PV system was also carried out in this study except for the hydro system which was not carried out due to the time allocated to conduct this study. The proposed operation scheme for the two hydro stations and the solar PV system is also carried out in order to increase solar power penetration in the Zambian grid, reduce power deficit and conserve water during the days/times with enough solar power.

     

    Designing of the system was carried out using Homer Pro software on which the hydro power station was modelled using the water influx into the turbines at KGUPS, the plant net head of 400 meters was also used with the calculated head losses of 7 % for the 4 meter diameter penstock between KGUPS dam, KGUPS machine hall to the KGLPS dam. The KGUPS dam was modelled as a natural battery so that charging is done using the water from the KGLPS dam, the battery with a total annual capacity of 428 GWh was modelled. PVsyst and PVGIS software tools were also used to simulate the production from the optimised PV system so that the accuracy of tools can be compared.

     

    To cover the load of 777 MW/day (18.6 GWh/day), the available power to provide the necessary energy for the pumps was 270 MW as surplus power from the hydro power machines at KGUPS .The available power from solar PV plant of 236 MW maximum was achieved from the optimized 300 MW PV plant in the dry period of the day which occurs in the month of October, with 300 MW converter , 8 % penetration of solar into the Zambian grid and the pumping scheme was able to provide 589 hours of autonomy with 80 % average state of charge. The total maximum power of 390 MW was good enough to provide power to the two pumps of each 165 MW. From the simulations carried out in the increment of solar PV system from 50 MW to 350 MW, the reliance on hydro power can be reduced drastically and power deficits due to the drought situation as the case for the year 2016 can be alleviated. 300 MW PV plant was selected in order to match with the available land, machines to work as pumps and the initial investment cost to be loosely monitored. The optimized 300 MW PV system with the life of 30 years had a project capital cost of $113 million united states dollars with the levelized cost of electricity 0.0487 $/kWh. The solar PV plant has a payback period of 9 years considering the yearly production from solar PV of 534 GWh as simulated from Homer, PVGIS interactive tool gave an output of 491 GWh. Pumped hydro systems has the capability of utilizing the already existing structures like dams and turbines. They also have the capability of stabilizing the grid network and allow easy penetration of renewable energy technologies like wind and solar. With the government of Zambia pushing for more renewables in the grid by 2030, a pumped hydro project at KGUPS will certainly be able to stabilize the grid and provide a scheme that will be able to push thermal plants to run at full capacity and the efficiency can be improved. In accordance with the IEC TC (technical committee) [30] pumped hydro energy storage is a mature bulk energy technology offering stability and allowing the penetration of intermittent renewables like wind and solar.

  • 171.
    Ochs, Fabian
    et al.
    Univeristy of Innsbruck.
    Fedrizzi, Roberto
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Dermentzis, Georgios
    Univeristy of Innsbruck.
    D6.7 Guidelines on Systemic Approach and Checklist2016Report (Other academic)
  • 172.
    Ollas, Fredrik
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Kling, Mattias
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Analys av ett mikronät vid Ihushi Development Center i Tanzania2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This study covers a research about how a micro-grid have performed, and

    in this specific case at Ihushi Development Center in Tanzania.

    The Measurements that have been made, have followed a standard to be

    able to be used as a universal data for future studies or just directly be

    comparable to other micro-grids with a similar rig and conditions.

    During the study, a new model have been created to easily analyze the raw

    data and perform the necessary calculations, which also is of high value in

    coming work on this micro-grid.

    There have also been some simulations done due to the vast amount of

    errors that have been both scattered and continuously appearing, this had

    to be taken care of and the values needed have been extracted and

    estimated from other sources and methods.

    Efficiencies and performances have been calculated for different parts of

    the system and have been commented so they can in a fair way be used

    for an evaluation or a future study.

    These results have partially been compared with the previous evaluations,

    but due to missing data in the previous report, a complete comparison and

    conclusion have not been possible.

  • 173.
    Paavilainen, Janne
    Dalarna University, School of Technology and Business Studies, Energy Technology. Chalmers.
    Characterization of Chimney Flue Gas Flows: Flow Rate Measurements with Averaging Pitot Probes2016Licentiate thesis, monograph (Other academic)
    Abstract [en]

    Performance testing methods of boilers in transient operating conditions (start, stop and combustion power modulation sequences) need the combustion rate quantified to allow for the emissions to be quantified. One way of quantifying the combustion rate of a boiler during transient operating conditions is by measuring the flue gas flow rate. The flow conditions in chimneys of single family house boilers pose a challenge however, mainly because of the low flow velocity. The main objectives of the work were to characterize the flow conditions in residential chimneys, to evaluate the use of the Pitot-static method and the averaging Pitot method, and to develop and test a calibration method for averaging Pitot probes for low 𝑅𝑅𝑅𝑅.A literature survey and a theoretical study were performed to characterize the flow conditions in in single family house boiler chimneys. The flow velocities under normal boiler operating conditions are often below the requirements for the assumptions of non-viscous fluid justifying the use of the quadratic Bernoulli equation. A non-linear calibration coefficient is required to correct for these viscous effects in order to avoid significant measurement errors. The flow type in the studied conditions changes from laminar, across the transition regime, to fully turbulent flow, resulting in significant changes of the velocity profile during transient boiler operation. Due to geometrical settings occurring in practice measurements are often done in the hydrodynamic entrance region, where the velocity profiles are neither fully developed nor symmetrical. The predicted changes in velocity profiles are also confirmed experimentally in two chimneys.Several requirements set in ISO 10780 and ISO 3966 for Pitot-static probes are either met questionably or not met at all, meaning that the methods cannot be used as such. The main issues are the low flow velocity, viscous effects, and velocity profiles that change significantly during normal boiler operation. The Pitot-static probe can be calibrated for low 𝑅𝑅𝑅𝑅, but is not reliable because of the changing velocity profiles.The pressure averaging probe is a simple remedy to overcome the problems with asymmetric and changing velocity profiles, but still keeping low the irrecoverable pressure drop caused by the probe. However, commercial averaging probes are not calibrated for the characterized chimney conditions and the information available on the performance of averaging probes at low 𝑅𝑅𝑅𝑅 is scarce. A literature survey and a theoretical study were done to develop a method for calibrating pressure averaging probes for low 𝑅𝑅𝑒 flue gas flows in residential chimneys.The experimental part consists of constructing a calibration rig, testing the performance of differential pressure transducers, and testing a prototype pressure averaging probe. The results show good correlation over a wide operation range, but the low 𝑅𝑅𝑅𝑅 characteristics of the probe could not be identified due to instability in the chosen pressure transducer, and temperature correlation for one of the probes while not for the other. The differential pressures produced are close to the performance limitations of readily available transducers and it should be possible to improve the method by focusing on finding or building a suitable pressure transducer. The performance of the averaging method can be improved further by optimizing the geometry of the probe. Another way of reducing the uncertainty would be to increase the probe size relative to the conduit diameter to produce a higher differential pressure, at the expense of increasing the irrecoverable pressure drop.

  • 174.
    Pamidi R., Sreenivaasa
    et al.
    Exergy Ltd..
    Polidori, Carlo
    Veltha IVZW.
    Mattsson, Anders
    Dalarna University, School of Technology and Business Studies, Forest and Wood Technology.
    Hernandez Velasco, Marco
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Ghrissi, Meftah
    Robosoft SA.
    Carrel, Aubert
    Robosoft SA.
    Menta, Andrea
    CO.MET.ART. SAS.
    Ramiro, Manuel
    ADVANTIC Sistemas y Servicios.
    Kotilainen, Titta
    Valoya OY.
    Aikala, Lars
    Valoya OY.
    ZEPHYR Project – Deliverable D2.4: Technical specification for the Power system with solar panels2013Report (Other (popular science, discussion, etc.))
  • 175.
    Pamidi, Sreenivaasa R
    et al.
    Exergy Ltd..
    Hernandez Velasco, Marco
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Reducing the impact of forest plant production - Design of a stand-alone PV-hybrid system for powering an innovative forestry incubator2014In: 29th European Photovoltaic Solar Energy Conference and Exhibition Proceedings, 2014, p. 3811-3814Conference paper (Other academic)
    Abstract [en]

    Nowadays, the high demand of forestry products imposes a high pressure on the ecosystems and can derive in biodiversity lost and other ecological problems. Planted forests can contribute to more sustainable practices and help addressing other problems of global concern such as climate change, erosion and desertification. Large scale production of seedling is required to offset the high harvesting rates; however these intensive methods often have a negative impact on the environment. Funded by the European Commission under the Seventh Framework Programme (FP7), the ZEPHYR project consortium is developing innovative and cost-friendly technologies for the pre-cultivation of forestry species. These will be integrated into a functional and transportable system for pre-cultivation of seedlings, with zeroimpact on the environment and not affected by outdoor conditions. To achieve this, the incubator will be powered mainly by solar energy. This work aims to present the efforts made to design and optimize the solar photovoltaic (PV) system which will be mounted on the roof of the unit. Especially developed devices such as LED growth lamps and wireless sensors will be used to reduce energy consumption and monitor the cultivation process. A load profile study was conducted and the growth protocols were adapted to perform most of the tasks during daytime to use the energy from the PV panels directly. A battery bank will be designed to provide at least one day of autonomy in central European latitudes. Moreover, the power system will also be capable of connecting to the electricity grid or use a diesel generator as a backup.

  • 176. Pan, S.
    et al.
    Wang, H.
    Pei, F.
    Yang, L.
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    An investigation on energy consumption of air conditioning system in Beijing subway stations2017In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 142, p. 2568-2573Article in journal (Refereed)
    Abstract [en]

    This paper initially depicted on the energy consumption of air conditioning systems in Beijing subway stations. An investigation was conducted among ten underground subway stations to the examination of practical operation conditions of their cooling units. The overall field testing included information such as air conditioning system formation, equipment types, system operation parameters, energy consumption and system operation efficiency. The results showed that the COP value of refrigerators in the tested subway stations were generally high at about 4.4 in average. Nevertheless, the mean EER and SCOP values were nearly 27% and 48% lower than the average COP value due to the large amount of energy consumption in water pumps, cooling towers and fans. There was a big difference among each station in terms of the instantaneous power consumption of air conditioning systems. The most energy consuming station was nearly seven times higher than the least one. It was observed that there was a lack of maintenance and system operation strategy for these underground air condition systems. A promising potential for energy saving was found out within the air conditioning systems in Beijing subway stations.

  • 177. Pan, S
    et al.
    Xiong, Y
    Han, Y
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Xia, L
    Wei, S
    Wu, J
    Han, Mengjie
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    A study on influential factors of occupant window-opening behavior in an office building in China2018In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 133, p. 41-50Article in journal (Refereed)
    Abstract [en]

    Occupants often perform many types of behavior in buildings to adjust the indoor thermal environment. In these types, opening/closing the windows, often regarded as window-opening behavior, is more commonly observed because of its convenience. It not only improves indoor air quality to satisfy occupants' requirement for indoor thermal comfort but also influences building energy consumption. To learn more about potential factors having effects on occupants' window-opening behavior, a field study was carried out in an office building within a university in Beijing. Window state (open/closed) for a total of 5 windows in 5 offices on the second floor in 285 days (9.5 months) were recorded daily. Potential factors, categorized as environmental and non-environmental ones, were subsequently identified with their impact on window-opening behavior through logistic regression and Pearson correlation approaches. The analytical results show that occupants' window-opening behavior is more strongly correlated to environmental factors, such as indoor and outdoor air temperatures, wind speed, relative humidity, outdoor FM2.5 concentrations, solar radiation, sunshine hours, in which air temperatures dominate the influence. While the non-environmental factors, i.e. seasonal change, time of day and personal preference, also affects the patterns of window-opening probability. This paper provides solid field data on occupant window opening behavior in China, with high resolutions and demonstrates the way in analyzing and predicting the probability of window-opening behavior. Its discussion into the potential impact factors shall be useful for further investigation of the relationship between building energy consumption and window-opening behavior.

  • 178. Pan, Song
    et al.
    Du, Saisai
    Wang, Xinru
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Xia, Liang
    Liu, Jiaping
    Pei, Fei
    Wei, Yixuan
    Analysis and interpretation of the particulate matter (PM10 and PM2.5) concentrations at the subway stations in Beijing, China2019In: Sustainable cities and society, ISSN 2210-6707, Vol. 45, p. 366-377Article in journal (Refereed)
    Abstract [en]

    The particulate matters (PM10 and PM2.5) inside urban subway stations greatly influence indoor air quality and passenger comfort. This study aims to analyze and interpret the concentrations of PM10 and PM2.5, measured in several subway stations from October 9th to 22nd, 2016 in Beijing, China. The overall methodology was based on the Statistical Package for Social Science (SPSS) software while General linear model (GLM) and correlation analysis were further applied to examine the sensitivities of different variables to the particle concentrations. The data analysis showed the average overall mass ratio of PM concentrations inside subway station is about 68.7%, much lower than outdoor condition (79.6%). In the areas of the station hall and platform, the real-time PM10 and PM2.5 concentrations varied periodically. In working and operation offices, all rooms had much higher PM concentrations than the outdoor environment when its pollution level was level 3, in which the facility room reached the highest level, while the closed meeting room had the lowest. Correlation analysis results indicated that PM10 and PM2.5 concentrations were mutually correlated (average R2 = 0.854), and a strong linear correlation (R2 = 0.897) of the subway-station PM concentrations to the outdoor PM conditions, regardless of the outdoor atmospheric PM concentrations pollution level was. Nevertheless, the impact of passenger number and temperature & humidity on the station PM concentrations was less, when compared to the outdoor environment. This paper is expected to provide useful information for further research and design of effective prevention measures on PM in local subway stations, towards a more sustainable and healthier built environment in the city underground. 

  • 179. Pan, Song
    et al.
    Pei, Fei
    Wang, Hongwei
    Liu, Jiaping
    Wei, Yixuan
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Li, Guoqing
    Gu, Yaxiu
    Design and experimental study of a novel air conditioning system using evaporative condenser at a subway station in Beijing, China2018In: Sustainable cities and society, ISSN 2210-6707, Vol. 43, p. 550-562Article in journal (Refereed)
    Abstract [en]

    Air conditioning system (AC) contributes significantly to the energy consumption of underground metros. In China, most metro stations are designed with water-cooling centralized air conditioning (WC-AC) system, it has been found that several serious problems are brought by this conventional system, such as large space occupying, water leaking, cooling tower noise and low system efficiency. In order to solve these problems, a novel energy-efficient AC system incorporating an independent evaporative condenser (EC) has been proposed and installed at Futong metro station in Beijing, China. A series of pilot measurements were conducted to analyze the cooling performance and energy consumption of this novel EC-AC system. During the testing period, the average refrigeration efficiency of COP, SCOP and ACOP in A and B side is up to 3.8/3.9, 3.4/3.4 and 2.5/2.3. At the same time, some operation problems such as unbalanced working condition have been identified during measurement. The research indicates that such EC-AC system could be a feasible solution to enhance the energy efficiency and reduce the operational costs and carbon emission in metro stations.

  • 180. Pan, Song
    et al.
    Wang, Xinru
    Wei, Yixuan
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Gál, Csilla V
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Rend, Guangying
    Yan, Da
    Yong, Shi
    Wu, Jinshun
    Liu, Jiaping
    Cluster analysis for occupant-behavior based electricity load patterns in buildings: a case study in Shanghai residences2017In: Building Simulation, ISSN 1996-3599, E-ISSN 1996-8744, Vol. 10, no 6, p. 889-898Article in journal (Refereed)
    Abstract [en]

    In building performance simulation, occupant behavior contributes to large uncertainties, which often lead to considerable discrepancies between actual energy consumption and simulation results. This paper aims to extract occupant-behavior related electricity load patterns using classical K-means clustering approach at the initial investigation stage. Smart-metering data from a case study in Shanghai, China, was used for the load pattern analysis. The electricity load patterns of occupants were examined on a daily/weekly/seasonal basis. According to their load patterns, occupants were categorized as (a) white-collar workers, (b) poor or older families and (c) rich or young families. The daily patterns indicated that electricity use was much more random and fluctuated over a wide range. Most households of the monitored communities consumed relatively-low electricity; the characteristic double peak with higher level of consumption in the morning and evening were only apparent in a relatively small subset of residents (mostly white-collar workers). The weekly analysis found that significant load shifting towards weekend days occurred in the poor or old family group. The electricity saving potential was greatest in the white-collar workers and the rich or young family groups. This study concludes with recommendations to stakeholders utilizing our load profiling results. The research provides a rare insight into the electricity-use-related occupant behaviors of Shanghai residents through the case study of two communities. The findings of the study are also presented in a meaningful way so that they can directly aid the decision-making of governments and other stakeholders interested in energy efficiency. The research results are also relevant to the building energy simulation community as they are derived from observations, and thus can have the potential to improve the efficiency and accuracy of numerical simulation results.

  • 181.
    Pande, Sohum
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Bhaladhare, Raj
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Different Photovoltaic Penetration Rates for the Planned Area of Jakobsgardarna in Borlange, Sweden2018Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The municipality of Borlange is planning to build a new modern, social and an ecologically sustainable district due to an increase in the city’s population. Over 1200 homes shall be built for people from all sections of the society. Due to such high levels of migration into the city, it is of utmost importance for the society to ensure that all the new constructions would be energy efficient and focused towards the goal of creating a sustainable society. The main objective of this study is to understand the importance of planning for Photovoltaics (PV) in new areas and performing a series of simulations for different scenarios with varying degrees of PV penetration for the planned residential area of Jakobsgardarna in Borlänge, Sweden.

     

    This was achieved by determining the load profiles for all buildings by thorough investigation over the previous works in the analysis of household demand loads and calculating the available roof area in several orientations with the help of model maps drawn to scale. Due to varied types of roofs and their structures, it was assumed that all buildings have a similar roof structure i.e. tilted roofs having a tilt of 30°. Batch simulation was performed in PVSyst for a base case scenario which provides the reference point for determining the total PV power and the total PV output in all orientations.

     

    The PV penetration is measured in terms of energy by dividing the total PV output with the annual demand load. Various scenarios of PV penetration are created based on the available roof areas at particular roof orientations. It can be observed that the level of PV penetration is highly dependent on the orientation of roofs. A 17% of PV penetration is observed when PV is installed only on South-facing roofs while the PV penetration reduces drastically to 9% when PV is installed only on East-West facing roofs even though there isn’t a linear reduction in the available roof area.

     

  • 182.
    Perers, Bengt
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Anderssen, E.
    Nordman, R.
    Kovacs, P.
    A simplified heat pump model for use in solar plus heat pump system simulation studies2012In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 30, p. 664-667Article in journal (Refereed)
    Abstract [en]

    Solar plus heat pump systems are often very complex in design, with sometimes special heat pump arrangements and control. Therefore detailed heat pump models can give very slow system simulations and still not so accurate results compared to real heat pump performance in a system. The idea here is to start from a standard measured performance map of test points for a heat pump according to EN 14825 and then determine characteristic parameters for a simplified correlation based model of the heat pump. By plotting heat pump test data in different ways including power input and output form and not only as COP, a simplified relation could be seen. By using the same methodology as in the EN 12975 QDT part in the collector test standard it could be shown that a very simple model could describe the heat pump test data very accurately, by identifying 4 parameters in the correlation equation found. © 2012 The Authors.

  • 183.
    Perers, Bengt
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Kovacs, P.
    Olsson, M.
    Persson, M.
    Pettersson, U.
    A tool for standardized collector performance calculations including PVT2012In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 30, p. 1354-1364Article in journal (Refereed)
    Abstract [en]

    A tool for standardized calculation of solar collector performance has been developed in cooperation between SP Technical Research Institute of Sweden, DTU Denmark and SERC Dalarna University. The tool is designed to calculate the annual performance of solar collectors at representative locations in Europe. The collector parameters used as input in the tool are compiled from tests according to EN12975, without any intermediate conversions. The main target group for this tool is test institutes and certification bodies that are intended to use it for conversion of collector model parameters (derived from performance tests) into a more user friendly quantity: the annual energy output. The energy output presented in the tool is expressed as kWh per collector module. A simplified treatment of performance for PVT collectors is added based on the assumption that the thermal part of the PVT collector can be tested and modeled as a thermal collector, when the PV electric part is active with an MPP tracker in operation. The thermal collector parameters from this operation mode are used for the PVT calculations. © 2012 The Authors.

  • 184.
    Perez de la Mora, Nicolas
    et al.
    Universidad de las Islas Baleares.
    Bava, Federico
    Technical University of Denmark.
    Andersen, Martin
    Dalarna University, School of Technology and Business Studies, Energy Technology. Chalmers University of Technology.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Lennermo, Gunnar
    Mälardalens Hogskola.
    Nielsen, Christian
    PanEnergi.
    Furbo, Simon
    Technical University of Denmark.
    Martínes-Moll, Víctor
    Universidad de las Islas Baleares.
    Solar district heating and cooling: A review2017In: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, p. 1-23Article in journal (Refereed)
    Abstract [en]

    Both district heating and solar collector systems have been known and imple- mented for many years. However, the combination of the two, with solar collec- tors supplying heat to the district heating network, is relatively new, and no comprehensive review of scientific publications on this topic could be found. Thus, this paper summarizes the literature available on solar district heating and presents the state of the art and real experiences in this field. Given the lack of a generally accepted convention on the classification of solar district heating systems, this paper distinguishes centralized and decentralized solar district heating as well as block heating. For the different technologies, the paper describes commonly adopted control strategies, system configurations, types of installation, and integration. Real‐world examples are also given to provide a more detailed insight into how solar thermal technology can be integrated with district heating. Solar thermal technology combined with thermally driven chillers to provide cooling for cooling networks is also included in this paper. In order for a technology to spread successfully, not only technical but also eco- nomic issues need to be tackled. Hence, the paper identifies and describes dif- ferent

  • 185.
    Perman, Karin
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Hedlund, G.
    Örebro university.
    WREF 2012: Gender, ethnicity and energy use in multi-family houses - Swedish norms in a multi-etnic context2012In: World Renewable Energy Forum, WREF 2012, Including World Renewable Energy Congress XII and Colorado Renewable Energy Society (CRES) Annual Conference / [ed] Cheryl Fellows, American Solar Energy Society , 2012, Vol. 3, p. 1834-1840Conference paper (Refereed)
    Abstract [en]

    The aim of this paper is to present data and analysis of an investigation of a renewal project in a big public housing area in a Swedish municipality. The project will combine the creation of at better quality of daily life in the multi- family housing area with the aim to reduce energy consumption. The area is in great need of renewal. We study the interaction between technological and social activities. Our theoretical approach in this study is the concept gendered.

  • 186.
    Persson, Björn
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Design and Implementation of a Supervisory Controller for PV and Storage2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Battery energy storage systems are a key factor for enabling a continuous increase of the fraction of photovoltaics in the Swedish electricity grid. One big challenge is to utilise all potential services of such a storage system. The aim of this study was to improve the supervisory controller for an existing battery storage and photovoltaic solution marketed by the Swedish company Ferroamp AB. This has been done by developing a combined peak reduction and time-of-use bill management algorithm, together with a simulation and evaluation software for optimisation of algorithm parameters. The algorithms and tools were evaluated using an installation made by Ferroamp AB and Vattenfall Eldistribution AB as a case study. Sensitivity analyses has been performed on economic parameters and length of the algorithm training data set. Improvement of economic profit, in this case study, were 300 % compared to the currently used algorithm and 32 % compared to a conventional threshold peak reduction algorithm. Despite this improvement, the battery energy storage system is shown to be non-profitable, with the economic profit only covering 36 % of the investment costs, not taking interest rate into account. Like in many other studies, power storage was found more profitable than energy storage. An increase of the grid power tariff and the grid energy fee of 30 % to 40 % is found to make the system viable. One interesting finding is that by using the proposed optimal algorithm, 55 % of the cycle life of the battery storage is still accessible for other services when considering 10 years of economic depreciation time for the system.

  • 187.
    Persson, Tomas
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Manikandan, Gokula
    Measurements of heat losses and energy labelling of storage tanks from Olle Jonsons Mekaniska, Hedemora2016Report (Other academic)
  • 188.
    Persson, Tomas
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Stavset, Ole
    SINTEF Energy Research.
    Ramstad, Randi Kalskin
    NTNU , Department of Geology and Mineral Resources Engineering.
    Alonso, Maria Justo
    SINTEF Energy Research.
    Lorenz, Klaus
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Software for modelling and simulation of ground source heating and cooling systems2016Report (Other academic)
    Abstract [en]

    The aim of this survey is to explore different simulation software for designing of ground source heating systems. Models to simulate borehole storages, heat pumps, and system components like water storages, hydraulics and building loads are explored. This study is based on a literature survey of software and models for simulation of geothermal heating and cooling systems with focus on vertical ground heat exchangers. The study focus on the software used by the authors, which are EED, TRNSYS, Polysun, Modelica, IDA ICE, and Matlab/Simulink+Carnot.  The scopes and limitations of the software and models are evaluated and the advantages and disadvantages with the software are addressed.  It was found that the user-friendliness is strongly linked to the level of flexibility in the models. Higher flexibility usually means less user-friendliness and more time to learn the tool. EED, Polysun and IDA are considered to be the more user friendly softwares, while Modelica, TRNSYS and Matlab/Simulink+Carnot are considered to be the more flexible softwares. The models covering most of the aspects of borehole simulations are the TRNSBM-model in TRNSYS and the “INTERACT 2016” model for Modelica.

  • 189.
    Persson, Tomas
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Wiertzema, Holger
    Win, Kaung Myat
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Modelling of dynamics and stratification effects in pellet boilers2019In: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 134, p. 769-782Article in journal (Refereed)
    Abstract [en]

    Optimizing solar and pellet heating systems can be performed by system simulations in TRNSYS. However; this requires detailed boiler models that can properly model the thermal behaviour of the boilers, such as stratification and thermal response. This study uses a combination of existing models for modelling of the pellet burner part (TRNSYS Type 210) and the water volume (TRNSYS Type 340). This approach addresses the thermal dynamics and internal stratification more accurately than other available models. The objectives of this work are to develop a method for parameter identification for the model and to validate this method and the model itself. Sets of parameters are identified for two pellet boilers and one pellet stove with a water jacket (extended room heater) and the model is validated with a realistic dynamic operation sequence. The results show that modelling of stratification is essential in order to model the true behaviour of residential boilers. The test sequences used were adequate to parameterise the models and to provide the desired accuracy, except regarding the heat losses to room air. The model shows good accuracy for a stove and one boiler, but slightly worse performance for the other boiler regarding dynamics and modelling of the stratification.

    The full text will be freely available from 2021-01-01 15:49
  • 190. Petrovic, B.
    et al.
    Myhren, Jonn Are
    Dalarna University, School of Technology and Business Studies, Construction.
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Wallhagen, M.
    Eriksson, O.
    Life cycle assessment of building materials for a single-family house in Sweden2019In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 158, p. 3547-3552Article in journal (Refereed)
    Abstract [en]

    The Nordic countries have shown great interest in using Life Cycle Assessment (LCA) in the building sector compared to the past years. Sweden has set up an objective to be carbon neutral (no greenhouse gas emissions to the atmosphere) by 2045. This paper presents a case study of a single-family house “Dalarnas Villa” in the region Dalarna, Sweden within a 100-year perspective. The assessment is implemented using a new software based on hard data agreed by Environmental Product Declarations (EPDs). It focuses on building materials, transport distances of the materials, and replacement of essential construction materials. The LCA in this study demonstrates the environmental impact related to building materials from production and construction phase including transport, replacement and deconstruction phase. The study does not cover energy use and water consumption. The results show that the building slab made by concrete is the part of the construction most contributing to CO2e, while the wood frame and cellulose insulation have low environmental impact. Replacement of materials takes nearly half of total environmental impact over 100 years. Having a large share of wood-based products, make greenhouse gas emissions remains low.

  • 191. Petrovic, Bojana
    et al.
    Myhren, Jonn Are
    Dalarna University, School of Technology and Business Studies, Construction.
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Wallhagen, Marita
    Eriksson, Ola
    Life cycle assessment of a wooden single-family house in Sweden2019In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 251, p. 113-253, article id 113253Article in journal (Refereed)
    Abstract [en]

    To understand the reasons behind the large environmental impact from buildings the whole life cycle needs to be considered. Therefore, this study evaluates the carbon dioxide emissions in all stages of a single-family house in Sweden from the production of building materials, followed by construction and user stages until the end-of-life of the building in a life cycle assessment (LCA). The methodology applied is attributional life cycle assessment (LCA) based on ‘One Click LCA’ tool and a calculated life span of 100 years. Global warming potential (GWP) and primary energy (PE) are calculated by using specific data from the case study, furthermore the data regarding building materials are based on Environmental Product Declarations (EPDs). The results show that the selection of wood-based materials has a significantly lower impact on the carbon dioxide emissions in comparison with non-wood based materials. The total emissions for this single-family house in Sweden are 6 kg CO 2 e/m 2 /year. The production stage of building materials, including building systems and installations represent 30% of the total carbon dioxide equivalent emissions, while the maintenance and replacement part represents 37%. However, energy use during the in-use stage of the house recorded lower environmental impact (21%) due to the Swedish electricity mix that is mostly based on energy sources with low carbon dioxide emissions. The water consumption, construction and the end-of-life stages have shown minor contribution to the buildings total greenhouse gas (GHG) emissions (12%). The primary energy indicator shows the largest share in the operational phase of the house.

  • 192.
    Pius Perangatt, George
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Evaluating the Economic Feasibility of Utilizing Power Optimizers in Various PVSystems2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Integration of power optimizers in photovoltaic systems is standard practice in some parts of the world. Manufacturers claim that optimizers can significantly reduce electrical losses due to shading. Hence, it is important to investigate this claim and determine under what conditions it is economically warranted to utilize optimizers.

    In this thesis systems were modelled in PVSyst, for 6 different locations: Abu Dhabi, Borlänge, Madrid, New Delhi, Sydney, and Vienna. In each location there were 3 types of systems: a regular non-optimised system, a SolarEdge optimised system and a TIGO optimised system. Each of these systems had 10 variants where the amount of shading was varied. The system variants were simulated in PVSyst and the effect of power optimizers on electrical losses due to shading was analysed. Afterwards, payback periods were calculated for each system to determine under which conditions power optimizers are economically feasible.

    It was found that power optimizers significantly reduce electrical losses due to shading. In some scenarios, the losses were reduced by up to 58 %. However, in the current economic climate in 2018, it is not feasible to incorporate power optimizers, in photovoltaic systems in Abu Dhabi, New Delhi or Sydney. Furthermore, in Borlänge, Madrid, and Vienna, optimizers are only feasible if there are high levels of shading, which is not realistic for a regular photovoltaic system.

  • 193.
    Poppi, Stefano
    Dalarna University, School of Technology and Business Studies, Energy Technology. KTH.
    Solar heat pump systems for heating applications: Analysis of system performance and possible solutions for improving system performance2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Solar heat pump systems (SHPs) are systems that combine solar energy and heat pumps. SHPs have been investigated for several decades and have been proven to increase the share of renewable energy and reduce electric energy demand in residential heating applications. Many solar thermal heat pump systems have become market-available in recent years; however these systems are still not widely employed in the residential sector. This is due mainly to the high initial costs (investment and installation costs) of solar thermal heat pump systems, which limits their cost-effectiveness. Enhancing cost-effectiveness of solar thermal heat pump systems is necessary for a more effective and broader market penetration.

    In this thesis, solar thermal and photovoltaic systems combined with heat pumps for heating applications are treated. The overall aims of the thesis are to: 1) investigate techno-economics of SHPs and 2) investigate possible solutions for improving system performance of a reference solar thermal and heat pump system for residential heating applications.

    In the first part of the thesis, the influence of climatic boundary conditions on economic performance of SHPs has been investigated by means of: a) an economic comparison of SHPs found in the relevant literature and b) system simulations of the reference solar thermal heat pump system.

    In the second part of the thesis, potential solutions for improving system performance of the reference solar thermal heat pump system with limited change in system’ costs are investigated. A systematic approach was used for investigating cost-effectiveness of the system improvements in the reference system.

    Based on results of the cost-effectiveness analysis, some of the investigated system improvements were chosen for being included in the design of a novel solar thermal and air source heat pump system concept. The novel system was designed for a house standard with relatively high operating temperatures (55°C/45°C) in the space heating distribution system and for high space heating demand (123 kWh/m2·year). Finally, the thesis ends with a cost-effectiveness analysis of the novel system.

  • 194.
    Poppi, Stefano
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology. Department of Energy Technology, KTH.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Influence of hydraulics and control of thermal storage in solar assisted heat pump combisystems2014In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 48, p. 946-955Article in journal (Refereed)
    Abstract [en]

    This paper studies the influence of hydraulics and control of thermal storage in systems combined with solar thermal and heat pump for the production of warm water and space heating in dwellings. A reference air source heat pump system with flat plate collectors connected to a combistore was defined and modeled together with the IEA SHC Task 44 / HPP Annex 38 (T44A38) “Solar and Heat Pump Systems” boundary conditions of Strasbourg climate and SFH45 building. Three and four pipe connections as well as use of internal and external heat exchangers for DHW preparation were investigated as well as sensor height for charging of the DHW zone in the store. The temperature in this zone was varied to ensure the same DHW comfort was achieved in all cases. The results show that the four pipe connection results in 9% improvement in SPF compared to three pipe and that the external heat exchanger for DHW preparation leads to a 2% improvement compared to the reference case. Additionally the sensor height for charging the DHW zone of the store should not be too low, otherwise system performance is adversely affected

  • 195.
    Poppi, Stefano
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Techno-economic analysis of a novel solar thermal and air-source heat pump system2016Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    This paper presents a techno-economic analysis of a novel solar thermal and air source heat pump system. The system was designed for relatively high operating temperatures in the space heating circuit and included the use of a heat pump with vapor injection cycle and vacuum insulation on the storage tank. The system model was validated against measurements in laboratory and simulated in TRNSYS 17. Annual simulations were performed for the combination of two climates (Carcassonne and Zurich) and two house standards (SFH45 and SFH100) and the best results were achieved for the boundary conditions the system was designed for. For those conditions (Zurich and SFH100), the novel system showed potential for being cost-effective compared to state of art solar and heat pump system. The “additional investment limit”, i.e. the maximum extra investment cost for the novel system in comparison to a state of art benchmark system that gives a break even result for a period of 10 years, varied between 827 € and 2482 € depending on electricity price. The results of a sensitivity analysis showed that variations in electricity price affected the additional investment limit far more than the other economic parameters

  • 196.
    Poppi, Stefano
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology. KTH.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Haller, Michel Y.
    University of Applied Sciences HSR, Switzerland.
    Heinz, Andreas
    Institute of Thermal Engineering, Graz University of Technology.
    Influence of boundary conditions and component size on electricity demand in solar thermal and heat pump combisystems2016In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 162, p. 1062-1073Article in journal (Refereed)
    Abstract [en]

    Solar thermal and heat pump combisystems are used to produce domestic hot water (DHW) and space heating (SH) in dwellings. Many systems are available on the market. For an impartial comparison, a definite level of thermal comfort should be defined and ensured in all systems. This work studied the influence of component size on electricity demand for a state of the art solar thermal and heat pump system. A systematic series of parametric studies was carried out by using TRNSYS to show the impact of climate, load and size of main components as well as heat source for the heat pump. Penalty functions were used to ensure that all variations provided the same comfort requirements. Two reference systems were defined and modelled based on products on the market, one with ambient air and the other with borehole as heat source for the heat pump. The results show that changes in collector area from 5 to 15 m2 result in a decrease in system electricity of between 305 and 552 kW h/year. Changes in heat exchanger size for DHW preparation were shown to give nearly as large changes in electricity use due to the fact that the set temperature in the store was changed to give the same thermal comfort in all cases. Decrease in heat pump size was shown to give a decrease in electricity use for the ASHP in the building with larger heat demand while it increased or had only a small change for other boundary conditions. Heat pump losses were shown to be an important factor highlighting the importance of modelling this factor explicitly

  • 197.
    Poppi, Stefano
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology. KTH.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Heinz, Andreas
    Hengel, Franz
    Cheze, David
    Mojic, Igor
    Cialani, Catia
    Dalarna University, School of Technology and Business Studies, Economics.
    Analysis of system improvements in solar thermal and air source heat pump combisystems2016In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 173, p. 606-623Article in journal (Refereed)
    Abstract [en]

    A solar thermal and heat pump combisystem is one of many system alternatives on the market for supplying domestic hot water (DHW) and space heating (SH) in dwellings. In this study a reference solar thermal and air source heat pump combisystem was defined and modelled based on products available on the market. Based on the results of an extensive literature survey, several system variations were investigated to show the influence of heat pump cycle, thermal storage and system integration on the use of electricity for two houses in the climates of Zurich and Carcassonne. A singular economic cash flow analysis was carried out and the “additional investment limit” of each system variation was determined for a range of economic boundary conditions. This is the maximum extra investment cost for the system variant compared to the reference system that will give a break even result for a 10 year period. The results show that variations in electricity price affects the additional investment limit far more than the other economic parameters. Several of the variants show potential for achieving a cost benefit, but the potential varies a lot depending on load and climate boundary conditions. For all variants, the biggest difference in electricity savings was found for Zurich rather than in Carcassonne, which is explained by the larger heating load. However, in three cases the largest savings were for the SFH45 house despite the fact that the annual electricity use of the system is much lower than that for the SFH100 house, 3581 kW h/year compared to 8340 kW h/year. This was attributed to the fact that, in these cases, the operating level of the space heating circuit played a significant role, the SFH45 house being supplied with a 35/30 °C heating system while the SFH100 was supplied with a 55/45 °C heating system.

  • 198.
    Poppi, Stefano
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology. KTH.
    Sommerfeldt, N.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Madani, H.
    Lundqvist, P.
    Techno-economic review of solar heat pump systems for residential heating applications2018In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 81, p. 22-32Article in journal (Refereed)
    Abstract [en]

    Solar heat pump systems (SHPs) have been investigated for several decades and have been proven to increase the share of renewable energy and reduce electric energy demand in residential heating applications. Many review articles have been published on the subject, however literature discussing the techno-economics of different solar technologies (thermal, photovoltaic and hybrid thermal/photovoltaic) in combination with heat pumps is lacking, and thus to directly compare the merits of different SHPs is not an easy task. The objectives of this study are: a) review the different system boundaries and the main performance indicators used for assessing energetic and economic performances; b) review techno-economic studies in the literature and identify which studies give enough information and are compatible enough for making an economic inter-comparison; c) present an economic inter-comparison based on the identified systems. The results show that there is a lack of studies including an economic assessment of solar photovoltaic and heat pump systems. Additionally, there are no consistent boundaries or approaches to the study structures, making comparisons between systems difficult. In conclusion, a standardized or broadly accepted definition of technical and economic performance for SHPs is needed. Despite this, the study has shown that there are clear trends for decreasing payback times for SHPs, both solar thermal (ST) and photovoltaic (PV), with decreasing heating degree-days and with increasing solar resource.

  • 199.
    Psimopoulos, Emmanouil
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Bee, E.
    Luthander, R.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Smart control strategy for PV and heat pump system utilizing thermal and electrical storage and forecast services2017Conference paper (Refereed)
  • 200.
    Psimopoulos, Emmanouil
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology. Uppsala University.
    Bee, Elena
    University of Trento, Trento, Italy.
    Luthander, Rasmus
    Uppsala University.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Smart control strategy for PV and heat pump system utilizing thermal and electrical storage and forecast services2017Conference paper (Refereed)
    Abstract [en]

    In this study, a detailed model of a single-family house with exhaust air heat pump, PV system and energy hub developed in the simulation software TRNSYS 17 is used to evaluate energy management algorithms that utilize weather and electricity price forecasts. A system with independent PV and heat pump is used as a base case. The proposed control strategy is applied to the base case to optimize the available PV electricity production using short-term weather and electricity price forecasts. The three smart and predictive control algorithms were developed with the scope to minimize final energy by the use of the thermal storage of the building, the hot water tank and electrical storage. The results show reduction of the final energy of 26.4%, increase of the self-consumption to 60% and decrease of the annual cost of 15% when using the forecast services in combination with thermal and electrical storage compared to the base case.

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