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  • 51.
    Elemam, Aboubker
    Högskolan Dalarna, Akademin Industri och samhälle, Maskinteknik.
    Development of a ESES Solar Thermal Lab on Full Scale System2011Independent thesis Advanced level (degree of Master (One Year)), 12 poäng / 18 hpOppgave
    Abstract [en]

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

  • 52.
    ElSherif, Khaled
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Solar Powered Smart Street Post2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis work aimed to develop solar Photovoltaic (PV) powered smart street post. The post was set to serve on highways for wild animals’ detection and warn vehicles of possible crossings. The main aim was to design reliable standalone PV system via PVSyst software and experimenting four different PV technologies including a bifacial module under. Another aim was to select and develop the hardware and software terms of the smart street pot. Radar sensor and analog to digital (A/D) data acquisition (DAQ) card were set to be used for the motion detection. RF wireless communication module was used for communicating with nearby posts to send data and trigger warning light emitting diodes (LED) sign. A Raspberry Pi microcontroller was programmed to control the operation of the street post through processing the signal from radar sensor and communicating with nearby posts.

    The PV system design included generation of street post’s daily profile, sizing and selection of the components of the system including the module, battery, charge controller and power stage circuit. The later was designed to provide suitable voltage level and interface for the loads connected. PVSyst model was built and set to be located in Ulm, Germany. The design parameters were set, and different set of orientations were tested for each module.

    The simulation results showed bifacial module delivered a reliable PV system in case of south and south-east orientation and achieved better performance in other orientations in comparison to the other PV modules implemented. Due to limitations in PVSyst software the results provided had an overall uncertainty of 5%.

    The microcontroller was able to process the data from the radar sensor and DAQ card and perform fast Fourier transform (FFT). However, further processing of motion detection was complex to be included in the thesis work. The radar sensor and DAQ card provided signals with uncertainty of ± 3.4 mV. The RF wireless communication module transmitted signal over various ranges up to 150 m with time delay of 500 ms.

  • 53.
    Farag, Ahmed
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Gabriele, Giovanni
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    A Feasibility Study of Solar-Assisted District Heating in Torsång2018Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Nowadays, using renewable energy, especially solar, is an expanding trend in the Nordic

    countries. In the past few years, the Europian Union has issued energy efficiency directives

    [1] that obligated its member countries to involve 50 % of renewable energies in the

    district heating (DH) networks. This opens the door for the integration of solar energy in

    the existent heat generation plants.

    Borlänge Energi AB, a municipal energy company, owns and operates a DH plant and

    network in Torsång; a small-community village outside Borlänge, in Dalarna County,

    Sweden. The plant generates the required heat using conventional energy boilers fueled by

    wood pellets, grid electricity, and oil. The company suggested using the nearby empty land,

    owned by the municipality, for installing a solar thermal collector field.

    The thesis aims at doing a feasibility study of the possible integration of a solar thermal

    collector field to the existent DH plant in Torsång. The goal is to replace the oil boilers

    with solar energy and to estimate the amount of fuel and emissions that can be saved and

    their effects on economics.

    To achieve the appointed tasks, a planned strategy was developed. After visiting the site

    and collecting all relevant data, the missing hourly load was calculated. Thumb rules were

    used for system sizing. The Polysun simulation software is used to model and simulate the

    proposed system. Two collector models from the same manufacturer were tested. The

    effects of lowering the DH temperature and changing the pellet boiler shut-down period

    were investigated. A sensitivity analysis of the solar fraction was conducted to provide

    different sizing options. In the end, an economic evaluation of the proposed solutions was

    made.

    The results revealed that, for all cases, the oil boilers could be successfully replaced saving

    0.6 m3 of diesel oil and 1.1 ton of CO2 emissions annually. A solar fraction of around 35 %

    was achieved. Shutting down the pellet boiler in the three summer months was proposed

    which reduced its operating time. Consequently, the pellet boiler energy production and

    the fuel consumption reduced by around 36 %. While its CO2 emissions are mitigated by

    26 %.

    The project, from the economic perspective, is showing a competitive value of LCOH

    (between 386 and 423 SEK/MWh) which is lower than the actual cost of the produced

    heat by the plant (500 SEK/MWh). The payback period is quite reasonable with values

    between 24 and 37 years, depending on the chosen solution. Governmental subsidies are

    not taken into consideration in the economic analysis, so the proposed values represent an

    upper boundary, which can be lowered whenever any incentive will be granted to the

    project.

    The proposed system makes room for two possible solutions: the first allows to shut-down

    the pellet boiler for the whole summer, thus giving more flexibility for the maintenance of

    it, benefits in terms of fuel and related emissions saved, but increasing the electricity

    consumption. The second solution, instead, is offering a shorter shut-down time, but with

    more monetary benefits.

  • 54.
    Fedorov, Anton
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Photovoltaic System Design for a Contaminated Area in Falun – Comparison of South and East- West Layout2015Independent thesis Advanced level (degree of Master (Two Years)), 10 poäng / 15 hpOppgave
    Abstract [en]

    In this thesis the solar part of a large grid-connected photovoltaic system design has been done. The main purpose was to size and optimize the system and to present figures helping to evaluate the prospective project rationality, which can potentially be constructed on a contaminated area in Falun. The methodology consisted in PV market study and component selection, site analysis and defining suitable area for solar installation; and system configuration optimization based on PVsyst simulations and Levelized Cost of Energy calculations.

    The procedure was mainly divided on two parts, preliminary and detailed sizing. In the first part the objective was complex, which included the investigation of the most profitable component combination and system optimization due to tilt and row distance. It was done by simulating systems with different components and orientations, which were sized for the same 100kW inverter in order to make a fair comparison. For each simulated result a simplified LCOE calculation procedure was applied. The main results of this part show that with the price of 0.43 €/Wp thin-film modules were the most cost effective solution for the case with a great advantage over crystalline type in terms of financial attractiveness.

    From the results of the preliminary study it was possible to select the optimal system configuration, which was used in the detailed sizing as a starting point. In this part the PVsyst simulations were run, which included full scale system design considering near shadings created by factory buildings. Additionally, more complex procedure of LCOE calculation has been used here considered insurances, maintenance, time value of money and possible cost reduction due to the system size.

    Two system options were proposed in final results; both cover the same area of 66000 m2. The first one represents an ordinary South faced design with 1.1 MW nominal power, which was optimized for the highest performance. According to PVsyst simulations, this system should produce 1108 MWh/year with the initial investment of 835,000 € and 0.056 €/kWh LCOE. The second option has an alternative East-West orientation, which allows to cover 80% of occupied ground and consequently have 6.6 MW PV nominal power. The system produces 5388 MWh/year costs about 4500,000 € and delivers electricity with the same price of 0.056 €/kWh. Even though the EW solution has 20% lower specific energy production, it benefits mainly from lower relative costs for inverters, mounting and annual maintenance expenses.

    After analyzing the performance results, among the two alternatives none of the systems showed a clear superiority so there was no optimal system proposed. Both, South and East-West solutions have own advantages and disadvantages in terms of energy production profile, configuration, installation and maintenance. Furthermore, the uncertainty due to cost figures assumptions restricted the results veracity.

  • 55. Fedrizzi, Roberto
    et al.
    Dipasquale, Chiara
    Bellini, Alessandro
    Gustafsson, Marcus
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Ochs, Fabian
    Dermentzis, Georgios
    Nouvel, Romain
    Cotrado, Mariela
    D6.3a Performance of the Studied Systemic Renovation Packages - Method2015Rapport (Annet vitenskapelig)
    Abstract [en]

    One of the primary objectives of the iNSPiRe project was to develop a tool that predicts the energy and cost saving impacts of various systemic retrofit interventions. This tool is now available for all those involved in the renovation of older buildings (from consulting offices, moving through construction companies and to decision makers) to use as a means of selecting which retrofit package will deliver the greatest costs savings and most improved energy efficiencies.To this purpose, we have produced three databases that provide valuable information about the energy performance of a variety of buildings in different climates, based on different energy requirements. These are the results of a three stage process:1. Collection of energy use data (statistics) for the whole of EU 27, the structuring of a building stock database and the definition of reference buildings that represent the most typical buildings of the building stock. Data for six different age categories were derived, including typical construction information and insulation standards for these periods. Seven climatic regions were also defined to cover the EU 27. The structured data are available in the Building Stock Statistics database.2. Derivation of a complete and consistent database of heating and cooling demands in residential and office buildings covering the whole of the EU 27 based on the simulation of the defined reference buildings in seven climatic regions. The simulations were calibrated against the energy use statistics, and are thus consistent with these, but offer the full range of heating and cooling demands for all climates and building types for six different age categories. The results are available in the Reference Building Simulation database.3. Definition of a range of retrofit measures for the reference buildings including climatic shell, HVAC system and heating/cooling distribution. The matrix of these measures was then simulated for all building types for the seven different climatic regions to provide data for the third database, the Systemic Renovation Packages database.

  • 56. Fedrizzi, Roberto
    et al.
    Dipasquale, Chiara
    Bellini, Alessandro
    Gustafsson, Marcus
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Ochs, Fabian
    Dermentzis, Georgios
    Nouvel, Romain
    Cotrado, Mariela
    D6.3b Performance of the Studied Systemic Renovation Packages - Single Family Houses2015Rapport (Annet vitenskapelig)
    Abstract [en]

    One of the primary objectives of the iNSPiRe project was to develop a tool that predicts the energy and cost saving impacts of various systemic retrofit interventions. This tool is now available for all those involved in the renovation of older buildings (from consulting offices, moving through construction companies and to decision makers) to use as a means of selecting which retrofit package will deliver the greatest costs savings and most improved energy performance.The whole set of Renovation Packages in the published database includes results for a range of SFH typologies, from detached to row houses, with different external surface over building volume ratio.In order to compare the same Envelope Renovation when applied to different SFH typologies and climates, we adopted the detached constructions as the basis to define insulation, windows and mechanical ventilation measures that match the heating demand standards sought (15, 25, 40, 70 kWh/m2y). Since the solutions found are the most conservative, lower heating demands are obtained for semi-detached and row houses.The solutions elaborated in terms of window features, and walls/roof cross sections and materials, are reported in Deliverable 6.3a for the whole range of buildings and the 7 climates analysed.In this document we comment the results relative to the reference buildings built 1945-1970, renovated with four generation systems (AWHP, GWHP, gas boiler and biomass boiler) and three distribution systems (radiant ceilings, radiators and fan coils). In order to limit the number of solutions discussed, here we report results only for the detached SFHs. The full range of solutions is published on the iNSPiRe website.The generation plants are hybrid solutions designed to combine heat pumps or boilers with solar thermal and/or PV technologies. These combinations integrate multiple renewable energy sources, thus allowing to reach in the best cases the 50 kWh/m2y primary energy consumption limit that is the objective of the retrofit packages devised.

  • 57. Fedrizzi, Roberto
    et al.
    Dipasquale, Chiara
    Bellini, Alessandro
    Gustafsson, Marcus
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Ochs, Fabian
    Dermentzis, Georgios
    Nouvel, Romain
    Cotrado, Mariela
    D6.3c Performance of the Studied Systemic Renovation Packages - Multi-Family Houses2015Rapport (Annet vitenskapelig)
    Abstract [en]

    In this report, we comment the results relative to the reference buildings built within the first age (1945-1970), and renovated with 4 generation systems (air to water heat pump, ground water heat pump, gas boiler and biomass boiler) and 3 distribution systems (radiant ceilings, radiators and fan coils).According to the buildings classification (see D2.1a and D2.1c), two different Multi Family Houses typologies are identified, small Multi Family House (s-MFH) and large Multi Family House (l-MFH). In the published database, only s-MFHs are included, varying the number of floors (3, 5 and 7 floors) and, consequently, the surface over volume (S/V) ratio.As well as for the SFHs, we adopted a reference S/V ratio as the basis to define insulation, windows and mechanical ventilation measures to match the sought heating demand targets (15, 25, 45, 70 kWh/m²y), that is 5 floors and 10 apartments.

  • 58. Freitas, Iuri
    et al.
    Zhang, Xingxing
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Green building rating systems in Swedish market: A comparative analysis between LEED, BREEAM SE, GreenBuilding and Miljöbyggnad2018Inngår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 153, s. 402-407Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In Sweden, there are four most commonly used green building rating systems, which are LEED, BREEAM SE, GreenBuilding and Miljöbyggnad. In this study, each of them is analyzed under the aspects of certification process, implementation cost, educational needs and the variety of categories. SWOT method is further applied to extract the strengths, weaknesses, opportunities and threats of each of the rating system in a direct and indirect manner, making it clearer to choose among various options when considering the individual needs of each project in practice. 

  • 59.
    Frota de Albuquerque Landi, Fabiana
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Energy Performance Contracting in Swedish scenario: a case study with Morastrand AB2018Independent thesis Advanced level (degree of Master (Two Years)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Renovation of the existing buildings in Sweden represents a great potential to achieve the

    energy efficiency and carbon emission targets set by the European Union and the Swedish

    government. The Energy Performance Contracting (EPC) is regarded as an efficient way

    to manage and to outsource the risks of energy efficiency (EE) measures.

    The thesis aims to identify the theoretical framework of EPC in the Swedish scenario and,

    through a real case, develop a model that relates EE measures and its results considering

    the capital investment versus running costs of renovation projects.

    The work is based on the incorporation with the Morastrand AB. The research expects to

    assess EPC processes and measures as in Energy Service Companies (ESCO) and

    consequently help in the decision making and the management of the projects.

    The thesis is composed of two parts. The first part identifies the theoretical framework of

    energy contract models focusing on the EPC, while a case study with Morastrand AB is

    subsequently presented. It is suggested one approach for the preliminary comparison of

    different renovation measures in EE projects, corresponding to the first step of the

    planning phase of an EPC.

    General recommendations and sensitive factors were identified and can assist Morastrand

    AB to effectively implement EE projects in the future. For orienting investments, the

    Lifecycle Cost Analysis (LCCA) is a method to study solutions under economic aspects

    and further it can be extended to the complete Lifecycle Assessment of the upcoming

    projects.

    The theoretical framework of the EPC is composed by identifying the projects, performing

    the technical analysis, determinizing the potential in energy savings, deepening the

    analysis with auditions, tendering the project, designing and executing the project,

    commissioning, operating and supporting the systems with constant monitoring and

    maintenance.

    The biggest challenge for the EPC in Sweden is the relation between the ESCOs and their

    clients. The figure of the facilitator could improve the results and balance the knowledge

    gap between the parts.

    The actors of these projects are the ESCO, the client, the facilitator and the financing part.

    In Sweden, very frequently the client finances the operation. There are a few models of

    contracting, and the most popular are guaranteed savings and shared savings.

    The thesis performed the LCCA of three options for window replacement in a building at

    the end of its lifespan. The results show that the trends in prices and interest rates are

    sensitive factors. In this case, the projects with higher initial investments were more

    profitable. Those solutions can shield the company against energy prices escalates and

    contribute to the green policies.

  • 60.
    Gerardi, Marcelin
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Namsrai, Miki
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    A software system for variables comparison of a paper machine for improved performance2018Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Today paper is to find everywhere, and the production factories always need to increase the

    productivity if they want to stay competitive. Stora Enso Kvarnsveden has one of the biggest

    magazine paper machines in the world, which produces around 1900 meters of paper per

    minute. The production process is highly automatized, which reduces the number of operators

    that work on the machine. Still, process variations can cause brakes in the paper web and lead

    to loss of income, energy and paper production. It may also have a direct impact on the paper

    quality. This report is focusing the following question:

    How to keep the Paper Machine production process under controlled conditions?

    To make a data analysis fully relevant, we need to use the most important variables of the

    machine. By analyzing these data some unexpected behavior and variation of process values

    can be pointed out. The analyzing tool needs to be fast and portable, and therefore a software

    system has been developed. By comparing process data with reference data this software can

    make a powerful analysis.

    The created software is intended to be used either by operators or engineers. The most

    important results are collected in a file. In this text file, the comparison function gives the

    results which are stored in a CSV-format. Furthermore, an auto-update function allows the

    users to run it automatically. Graphical presentations are supporting the interpretation of the

    results.

  • 61.
    Ghaghazanian, Arash
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    System Integration of PV/T Collectors in Solar Cooling Systems2015Independent thesis Advanced level (degree of Master (Two Years)), 10 poäng / 15 hpOppgave
    Abstract [en]

    The demand for cooling and air-conditioning of building is increasingly ever growing. This increase is mostly due to population and economic growth in developing countries, and also desire for a higher quality of thermal comfort. Increase in the use of conventional cooling systems results in larger carbon footprint and more greenhouse gases considering their higher electricity consumption, and it occasionally creates peaks in electricity demand from power supply grid. Solar energy as a renewable energy source is an alternative to drive the cooling machines since the cooling load is generally high when solar radiation is high.

    This thesis examines the performance of PV/T solar collector manufactured by Solarus company in a solar cooling system for an office building in Dubai, New Delhi, Los Angeles and Cape Town. The study is carried out by analyzing climate data and the requirements for thermal comfort in office buildings. Cooling systems strongly depend on weather conditions and local climate. Cooling load of buildings depend on many parameters such as ambient temperature, indoor comfort temperature, solar gain to the building and internal gains including; number of occupant and electrical devices.

    The simulations were carried out by selecting a suitable thermally driven chiller and modeling it with PV/T solar collector in Polysun software. Fractional primary energy saving and solar fraction were introduced as key figures of the project to evaluate the performance of cooling system. Several parametric studies and simulations were determined according to PV/T aperture area and hot water storage tank volume.

    The fractional primary energy saving analysis revealed that thermally driven chillers, particularly adsorption chillers are not suitable to be utilizing in small size of solar cooling systems in hot and tropic climates such as Dubai and New Delhi. Adsorption chillers require more thermal energy to meet the cooling load in hot and dry climates. The adsorption chillers operate in their full capacity and in higher coefficient of performance when they run in a moderate climate since they can properly reject the exhaust heat. The simulation results also indicated that PV/T solar collector have higher efficiency in warmer climates, however it requires a larger size of PV/T collectors to supply the thermally driven chillers for providing cooling in hot climates. Therefore using an electrical chiller as backup gives much better results in terms of primary energy savings, since PV/T electrical production also can be used for backup electrical chiller in a net metering mechanism.

  • 62.
    Gilén, Karolina
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Haglund, Arvid
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Sammankoppling av fjärrvärmenät: Transiteringsledning mellan Borlänge, Ornäs och Torsång2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Borlänge Energi, BE, owns small district heating, DH, networks in Ornäs and Torsång outside Borlänge, these have high operating costs that are not weighed up by the revenue they make, due to this BE makes a yearly loss on them. Because of this BE wants to connect the small DH networks with the main DH network in Borlänge where the production costs are lower. The technical and economical prerequisites for a connection have therefore been studied.

    Previous literature has been studied regarding economic parameters for connection of DH networks. Unfortunately, the type of connection that is studied in this report has not been found. The studied literature covers expansion of DH network and connection of larger DH networks, and in most cases, the connecting networks have different owners.

    Three possible routes were chosen for the connection with Borlänges DH. The current load for Ornäs and Torsång as well as possible new customers was calculated and used to dimension the pipes and calculate the costs for three different scenarios with different loads. Thereafter the costs and incomes from a connection has been calculated, and then used in BEs capital budget where the pay-off time was calculated based on the discounting method. The capital budgets showed that all the routes except one in the base case were profitable within the time frame of 30 years that was set by BE for investments in DH. Sensitivity analyses were made for pay-off time, construction costs and pipe dimension, which showed that the pay-off time is affected by several factors. But was mostly affected if production costs increase or if pipes are dimensioned for a much larger load than what actually is connected in the end. The number of new customers is therefor important to ensure before building the interconnecting pipe. Pipe dimension was affected most by the load as the transition losses are relatively small, and the building costs were affected most by the cost of the DH pipes since they constitute a large part of those costs.

    Besides from the technical and economical results it has been shown that each and all of the routes have its own prerequisites, where each route has its own pros and cons. All-in-all one route has been chosen as more suitable than the other two, as it besides one of the shortest pay off times also include possibilities to connect new customers along the route.

    As district heating is dependent on local conditions, in regard to both the technical aspects and the soil composition, the report includes several simplifications and assumptions, which have been made based on local conditions and experience. It is necessary to take this into consideration before attempting to apply the findings of this report in other places than Borlänge.

  • 63.
    Graefenhain, Marcus
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Energy Yield Simulation Analysis of Bifacial PV Installations in the Nordic Climate2017Independent thesis Advanced level (degree of Master (Two Years)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Recently, commercial softwares for PV system simulation released bifacial extensions. While research laboratories have developed their own simulation tools, in both cases it is imperative to display their applicability, as well as continuously assess their accuracy and/or limitations in practice, i.e. for different bifacial PV systems and field conditions. This paper presents a design and energy yield simulation study of two bifacial PV systems installed and operating in Nordic climate conditions, i.e. in Vestby, Norway (

    System 1) and in Halmstad, Sweden (System 2). The aim of this study is:

    • • To validate and compare the accuracy of two bifacial PV simulation tools newly featured in the software platforms of PVsyst and Polysun respectively, against real-field energy yield data.

    Each investigated system is modeled and analyzed with both simulation tools, resulting in four individual case stu

    dies. Further details on the systems’ monitoring set-up, the data input, modeling steps, and the involved uncertainties are presented in this paper.

    The results of the four case studies show higher percent deviations (both monthly and hourly data) between simulated energy results and real energy results during winter periods compared to summer periods. System 1 had a lower bifacial gain (around 2%) than System 2 which ranges from 2% in summer periods to 25% during winter.

    The collected field data had too high of an uncertainty to determine whether the bifacial PV simulation extensions are accurate within a certain tolerance. The reason for higher simulation inaccuracy in the winter is due to: lower production, higher uncertainty in albedo, and more diffuse irradiation.

    It is recommended for the bifacial PV simulation extensions include options for considering a variable albedo. The bifacial gain in System 2 was higher in the winter because of the higher albedo value given whereas in System 1, the albedo value was kept constant. Further parametric studies should be conducted on the bifacial gain using vertical mounted bifacial PV modules oriented east and west for Nordic climate conditions.

  • 64.
    Grälls, Gustav
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Kemell, Tim
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Energieffektivisering av glödskalsspolning: Utredning av högtryckssystem för glödskalsspolning, med avseende på energieffektiviserande förbättringar och förslag till åtgärder.2016Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    The hot rolling mill at SSAB in Borlänge uses large amounts of electricity every year. The work of systematically reducing energy usage is an ongoing process, both for the sake of the environment but also for increasing profit in the production. The high pressure system for descaling uses 20 GWh of electricity every year. This is about 10 % of the hot rolling mills total electricity usage. The steel slabs are heated before being rolled. This causes iron and oxygen to react with each other and form a scale. This scale is not desired in steel production which is why several methods to remove it have been developed. The method being used at SSAB is high pressure water descaling.

    Large volumes of water are being pressurized and sprayed through nozzles in thin triangle-like jets against the steel. To remove the scale a certain amount of energy is required. It can be calculated by using impingement pressure as a function of specific water rate (amount of water per square meter). This thesis is based on the assumption that the energy usage in the total system can be reduced without reducing the amount of energy that strikes the steel surface. The total efficiency of the system is today 39 %.

    A big contribution to the low efficiency is that all pumps are running on constant rotational speed. They need a minimal flow of water through them for cooling. This minimal flow is according to the manufacturer supposed to be 12 m3/h, but in reality they run at 30 m3/h. This is because of wear in the relief valves that are supposed to reduce the drainage flow. The relief valves are also designed to close the minimal flow to drain during descaling. This is not working as it should and water is flowing to drain during descaling. This result in the yearly energy usage increasing with 3 GWh. Additionally, because of the increased flow to the drain, energy usage is increased by around 6 %. The accumulators being used, four in total at 7 m3 each, are not used in an optimal way. Some observations have been done and at those times the tanks have been filled with about 50 % water. An accumulator should, according to theory, be empty when reaching lowest allowed system pressure. As being used today only a few percent of the tanks water volume can be used.

    A suggestion of bigger change that has been developed is to change pumps and to install bigger accumulators at the furnace and roughing descaler. This would then be made into a separate system, separated from the finishing descaler. An advantage with separate systems is that the parts can be dimensioned for different pressures. This could be especially interesting if piston pumps are installed in the accumulator system.

  • 65. Gustafsson, M.
    et al.
    Rönnelid, Mats
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Trygg, L.
    Karlsson, B.
    CO2 emission evaluation of energy conserving measures in buildings connected to a district heating system: Case study of a multi-dwelling building in Sweden2016Inngår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 111, s. 341-350Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    When taking action to fulfill the directives from the European Union, energy conserving measures will be implemented in the building sector. If buildings are connected to district heating systems, a reduced heat demand will influence the electricity production if the reduced heat demand is covered by combined heat and power plants.This study analyze five different energy conserving measures in a multi-dwelling building regarding how they affect the marginal production units in the district heating system in Gävle, Sweden. For CO2 emission evaluations, two different combinations of heat and electricity conserving measures are compared to an installation of an exhaust air heat pump.The different energy conserving measures affect the district heating system in different ways. The results show that installing an exhaust air heat pump affects the use/production of electricity in the district heating system most and electricity conserving measures result in reduced use of electricity in the building, reduced use of electricity for production of heat in the district heating system and an increase of electricity production.The conclusion is that electricity use in the building is the most important factor to consider when energy conserving measures are introduced in buildings within the district heating system in Gävle.

  • 66.
    Gustafsson, Marcus
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik. KTH.
    Energy efficient and economic renovation of residential buildings with low-temperature heating and air heat recovery2015Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    With the building sector accounting for around 40% of the total energy consumption in the EU, energy efficiency in buildings is and continues to be an important issue. Great progress has been made in reducing the energy consumption in new buildings, but the large stock of existing buildings with poor energy performance is probably an even more crucial area of focus. This thesis deals with energy efficiency measures that can be suitable for renovation of existing houses, particularly low-temperature heating systems and ventilation systems with heat recovery. The energy performance, environmental impact and costs are evaluated for a range of system combinations, for small and large houses with various heating demands and for different climates in Europe. The results were derived through simulation with energy calculation tools.

    Low-temperature heating and air heat recovery were both found to be promising with regard to increasing energy efficiency in European houses. These solutions proved particularly effective in Northern Europe as low-temperature heating and air heat recovery have a greater impact in cold climates and on houses with high heating demands. The performance of heat pumps, both with outdoor air and exhaust air, was seen to improve with low-temperature heating. The choice between an exhaust air heat pump and a ventilation system with heat recovery is likely to depend on case specific conditions, but both choices are more cost-effective and have a lower environmental impact than systems without heat recovery. The advantage of the heat pump is that it can be used all year round, given that it produces DHW.

    Economic and environmental aspects of energy efficiency measures do not always harmonize. On the one hand, lower costs can sometimes mean larger environmental impact; on the other hand there can be divergence between different environmental aspects. This makes it difficult to define financial subsidies to promote energy efficiency measures.

  • 67.
    Gustafsson, Marcus
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik. KTH, Strömnings- och klimatteknik.
    Energy Efficient Renovation Strategies for Swedish and Other European Residential and Office Buildings2017Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The high energy use in the European building stock is attributable to the large share of old buildings with poor energy performance. Energy renovation of buildings is therefore vital in the work towards energy efficiency and reduced environmental impact in the EU. Yet, the strategies and energy system implications of this work have not been made clear, and the rate of building renovation is currently very low.

    The aim of this thesis is to investigate the economic and environmental aspects of energy renovation strategies, with two main objectives:

    • Renovation of Swedish district heated multi-family houses, including life-cycle cost and environmental analysis and impact on the local energy system;

    • Renovation of European residential and office buildings, including life-cycle cost and environmental analysis and influence of climatic conditions.

    Buildings typical for the respective regions and the period of construction 1945-1970 were simulated, in order to determine the feasibility and energy saving potential of energy renovation measures in European climates. A variety of systems for heating, cooling and ventilation were studied, as well as solar energy systems, with focus on heat pumps, district heating, low-temperature heating systems and air heat recovery.

    Compared to normal building renovation, energy renovation can often reduce the life-cycle costs and environmental impact. In renovation of typical European office buildings, as well as Southern European multi-family houses, more ambitious renovation levels can also be more profitable.

    Exhaust air heat pumps can be cost-effective complements in district heated multi-family houses, while ventilation with heat recovery is more expensive but also more likely to reduce the primary energy use. From a system perspective, simple exhaust ventilation can reduce the primary energy use in the district-heating plant as much as an exhaust air heat pump, due to the lower electricity use.

  • 68.
    Gustafsson, Marcus
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik. KTH.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Myhren, Jonn Are
    Högskolan Dalarna, Akademin Industri och samhälle, Byggteknik.
    Holmberg, Sture
    KTH.
    Techno-economic analysis of three HVAC retrofitting options2014Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Accounting for around 40% of the total final energy consumption, the building stock is an important area of focus on the way to reaching the energy goals set for the European Union. The relatively small share of new buildings makes renovation of existing buildings possibly the most feasible way of improving the overall energy performance of the building stock. This of course involves improvements on the climate shell, for example by additional insulation or change of window glazing, but also installation of new heating systems, to increase the energy efficiency and to fit the new heat load after renovation. In the choice of systems for heating, ventilation and air conditioning (HVAC), it is important to consider their performance for space heating as well as for domestic hot water (DHW), especially for a renovated house where the DHW share of the total heating consumption is larger.

    The present study treats the retrofitting of a generic single family house, which was defined as a reference building in a European energy renovation project. Three HVAC retrofitting options were compared from a techno-economic point of view: A) Air-to-water heat pump (AWHP) and mechanical ventilation with heat recovery (MVHR), B) Exhaust air heat pump (EAHP) with low-temperature ventilation radiators, and C) Gas boiler and ventilation with MVHR. The systems were simulated for houses with two levels of heating demand and four different locations: Stockholm, Gdansk, Stuttgart and London. They were then evaluated by means of life cycle cost (LCC) and primary energy consumption. Dynamic simulations were done in TRNSYS 17.

    In most cases, system C with gas boiler and MVHR was found to be the cheapest retrofitting option from a life cycle perspective. The advantage over the heat pump systems was particularly clear for a house in Germany, due to the large discrepancy between national prices of natural gas and electricity. In Sweden, where the price difference is much smaller, the heat pump systems had almost as low or even lower life cycle costs than the gas boiler system. Considering the limited availability of natural gas in Sweden, systems A and B would be the better options. From a primary energy point of view system A was the best option throughout, while system B often had the highest primary energy consumption. The limited capacity of the EAHP forced it to use more auxiliary heating than the other systems did, which lowered its COP. The AWHP managed the DHW load better due to a higher capacity, but had a lower COP than the EAHP in space heating mode. Systems A and C were notably favoured by the air heat recovery, which significantly reduced the heating demand.

    It was also seen that the DHW share of the total heating consumption was, as expected, larger for the house with the lower space heating demand. This confirms the supposition that it is important to include DHW in the study of HVAC systems for retrofitting.

  • 69.
    Gustafsson, Marcus
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik. KTH.
    Dermentzis, Georgios
    Univeristy of Innsbruck.
    Myhren, Jonn Are
    Högskolan Dalarna, Akademin Industri och samhälle, Byggteknik.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Ochs, Fabian
    Univeristy of Innsbruck.
    Holmberg, Sture
    KTH.
    Feist, Wolfgang
    Energy performance comparison of three innovative HVAC systems for renovation through dynamic simulation2014Inngår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 82, s. 512-519Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this paper, dynamic simulation was used to compare the energy performance of three innovativeHVAC systems: (A) mechanical ventilation with heat recovery (MVHR) and micro heat pump, (B) exhaustventilation with exhaust air-to-water heat pump and ventilation radiators, and (C) exhaust ventilationwith air-to-water heat pump and ventilation radiators, to a reference system: (D) exhaust ventilation withair-to-water heat pump and panel radiators. System A was modelled in MATLAB Simulink and systems Band C in TRNSYS 17. The reference system was modelled in both tools, for comparison between the two.All systems were tested with a model of a renovated single family house for varying U-values, climates,infiltration and ventilation rates.It was found that A was the best system for lower heating demand, while for higher heating demandsystem B would be preferable. System C was better than the reference system, but not as good as A or B.The difference in energy consumption of the reference system was less than 2 kWh/(m2a) betweenSimulink and TRNSYS. This could be explained by the different ways of handling solar gains, but also bythe fact that the TRNSYS systems supplied slightly more than the ideal heating demand.

  • 70.
    Gustafsson, Marcus
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Dipasquale, C.
    Poppi, Stefano
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Bellini, A.
    Fedrizzi, R.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Ochs, F.
    Sié, M.
    Holmberg, S.
    Economic and environmental analysis of energy renovation packages for European office buildings2017Inngår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 148, s. 155-165Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A large share of the buildings in Europe are old and in need of renovation, both in terms of functional repairs and energy efficiency. While many studies have addressed energy renovation of buildings, they rarely combine economic and environmental life cycle analyses, particularly for office buildings. The present paper investigates the economic feasibility and environmental impact of energy renovation packages for European office buildings. The renovation packages, including windows, envelope insulation, heating, cooling and ventilation systems and solar photovoltaics (PV), were evaluated in terms of life cycle cost (LCC) and life cycle assessment (LCA) through dynamic simulation for different European climates. Compared to a purely functional renovation, the studied renovation packages resulted in up to 77% lower energy costs, 19% lower total annualized costs, 79% lower climate change impact, 89% lower non-renewable energy use, 66% lower particulate matter formation and 76% lower freshwater eutrophication impact over a period of 30 years. The lowest total costs and environmental impact, in all of the studied climates, were seen for the buildings with the lowest heating demand. Solar PV panels covering part of the electricity demand could further reduce the environmental impact and, at least in southern Europe, even reduce the total costs. © 2017 Elsevier B.V.

  • 71.
    Gustafsson, Marcus
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik. KTH.
    Myhren, Jonn Are
    Högskolan Dalarna, Akademin Industri och samhälle, Byggteknik.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Comparison of two HVAC renovation solutions: A case study2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Within the aging building stock of Europe, there is great potential of saving energy through renovation and upgrading to modern standards, and to thereby approach the internationally set goals of lower energy use. This paper concerns the planned renovation of the building envelope and HVAC systems in a multi-family house in Ludwigsburg, Germany. Five systemic HVAC solutions were compared, with special focus on two systems: A) Balanced ventilation with HRC + Micro heat pump, and B) Forced exhaust ventilation + Heat pump with exhaust air HRC + Ventilation radiators. Given the predicted heating demand and ventilation rate of the house after renovation, the performance of the two systems was compared, alongside three common systems for reference. Calculations were made using TMF Energi, a tool developed by SP Technical Research Institute of Sweden.

       Both systems A and B were found to have the lowest electrical energy use together with the ground source heat pump system for the assumed conditions. For other assumptions, including different climate and degree of insulation, some differences between these three systems were noted. Most significant is the increased electrical use of system B for higher heating loads due to limitations in the power available from the heat source, exhaust air, which is dependent on the ventilation rate.

  • 72.
    Gustafsson, Marcus
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik. KTH.
    Poppi, Stefano
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik. KTH.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Fedrizzi, Roberto
    Dipasquale, Chiara
    Bellini, Alessandro
    Ochs, Fabian
    Univeristy of Innsbruck.
    Dermentzis, Georgios
    Univeristy of Innsbruck.
    Performance of Studied Systemic Renovation Packages – Office Buildings2016Rapport (Annet vitenskapelig)
  • 73.
    Gustafsson, Marcus
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik. KTH.
    Swing Gustafsson, Moa
    Falu Energi och Vatten.
    Myhren, Jonn Are
    Högskolan Dalarna, Akademin Industri och samhälle, Byggteknik.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Holmberg, Sture
    KTH.
    Economic and environmental analysis of energy renovation measures for a district heated multi-family houseManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Renovation of existing buildings plays an important part in the work towards European climate and energy goals. The present paper treats energy efficiency renovation measures for a district heated Swedish multi-family house, evaluated through dynamic simulation. Five HVAC systems were studied in combination with three renovation levels, starting from basic renovation to maintain functionality and then adding 1) better insulating windows and flow-reducing water taps, and 2) additional insulation on roof and façade. The HVAC systems were based on the existing district heating substation and included mechanical ventilation with heat recovery and different configurations of exhaust air heat pump. Life cycle cost, discounted payback period, primary energy consumption, CO₂ emissions and non-renewable energy use were assessed for all combinations.

    The system with the lowest cost and environmental impact was, in most cases, the one where district heating and heat pump were combined for both heating and DHW. Low-temperature heating improved the performance factor of the heat pump, but reduced the heat output and increased the need for backup heating. Changing windows and water taps was found to be profitable, while additional insulation reduced the environmental impact but increased the life cycle cost.

  • 74.
    Gustafsson, Mattias
    et al.
    Högskolan i Gävle.
    Karlsson, Björn
    Högskolan i Gävle.
    Rönnelid, Mats
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    How the electric meter configuration affect the monitored amount of self-consumed and produced excess electricity from PV systems: case study in Sweden2017Inngår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 138, s. 60-68Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study evaluates how the principal function of bi-directional electric meters affects the monitored amount of self-consumed and produced excess electricity for dwelling buildings connected to the grid by three phases. The electric meters momentarily record the sum of the phases or the phases individually and then summarize the recorded values to a suitable time period and is then collected by the grid owner. In Sweden, both electric meter configurations fulfill laws and regulations.

    The meter configuration affects the monitored distribution of self-consumed and produced excess electricity significantly for the investigated single-family house but is negligible for the investigated multi-dwelling buildings. The monitored self-consumed electricity produced by the PV installation for the single-family house varies between 24% and 55% depending on the configuration and how the inverter is installed for the investigated year. The difference in economic value for the produced electricity varies between 79.3 to 142 Euros.

    Due to the electric meter configuration, the profitability of PV systems will be different for identical single-family houses with identical conditions. This should be corrected for a well-functioning market. It is also important to decide how the configuration should be designed to ensure that different incentives and enablers results in desired effects.

  • 75.
    Gómez, Camilo Andrés
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Influence of Vacuum in Heat Losses of Parabolic Trough Solar Receivers2016Independent thesis Advanced level (degree of Master (Two Years)), 10 poäng / 15 hpOppgave
    Abstract [en]

    In comparison with conventional power plants and other renewable technologies,

    the current cost of a Concentrating Solar Power plant is still very high. This

    situation has made the industry have the necessity to research in this field to

    improve efficiency and for a near future have lower cost. One of the developed field

    to improve the efficiency is to decrease the heat losses in the system therefore,

    having a better efficiency in the system.

    In this project, in collaboration of the Solar Platform of Almeria (PSA) in Spain, the

    purpose was to analyses the heat losses of a commercial parabolic trough solar

    receiver at different pressures inside the receiver (at the annulus space). The

    objective was finding the behavior of the heat losses as the pressure inside the

    receiver is increasing allowing convection between the absorber and the glass

    envelope. The PSA has developed a test bench in order to test any kind of linear

    solar receptor named HEATREC. The HEATREC allows to measure the heat

    losses of the receiver in a controlled environment at different temperatures. The

    receiver suffered a minor modification so the pressure in the annulus space can be

    control at will.

    The results shown in this experiment are represented mainly in two types of

    graphics. The first type shows the heat losses as a function of the temperature of

    the absorber tube, this one is used as a comparison with previews research to see

    if is having a correct behavior regardless the pressure in the annulus space is

    being change. The second type shows the heat losses as a function of the

    pressure in the annulus space inside the receiver. The experimental data show that

    there is a remarkable increase in the heat losses as the pressure inside the

    annulus space of the receiver increase and that it can be seen that there are two

    major points in the pressure where the heat losses increase drastically (from 10# to

    10$ mbar and from 10%& to 10%# mbar).

  • 76. Haller, M.
    et al.
    Paavilainen, J.
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Konersman, L.
    Droscher, A.
    Frank, E.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Streicher, W.
    A Unified Model for the Simulation of Oil, Gas, and Biomass Space Heating Boilers for Energy Estimating Purposes: Part I: Model Development2011Inngår i: Journal of Building Performance Simulation, Taylor & Francis, ISSN 1940-1493, E-ISSN 1940-1507, Vol. 4, nr 1, s. 1-18Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A unified model for the simulation of oil, gas, pellet and wood chip space heating boilers for energy estimating purposes has been developed based on a literature review and laboratory measurements on four different boilers. The model includes the influence of space heating return temperature, power modulation and condensation gains on the flue gas losses of the boiler, the simulation of a thermal boiler capacitance including its heat losses during standby and operation, and the ability to calculate carbon monoxide emissions and electricity use dependent on power modulation and number of burner starts. Some of the new features of the presented boiler model are the unification of models for oil, gas and biomass boilers into one model, and the combination of steady state calculation for the flue gas to water heat transfer with an explicit solution for the time dependent temperature change of the boiler’s thermal capacitance.

  • 77. Haller, M.
    et al.
    Paavilainen, J.
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Konersman, L.
    Haberl, R.
    Droscher, A.
    Frank, E
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Streicher, W.
    A Unified Model for the Simulation of Oil, Gas, and Biomass Space Heating Boilers for Energy Estimating Purposes: Part II: Parameterization and Comparison with Measurements2011Inngår i: Journal of Building Performance Simulation, Taylor & Francis, ISSN 1940-1493, E-ISSN 1940-1507, Vol. 4, nr 1, s. 19-36Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A semi-physical model for the simulation of oil, gas and biomass space heating boilers has been parameterized based on measurements on nine different boiler units and simulation results have been compared to results obtained from measurements in steady state and transient operation. Although the agreement between simulated and measured boiler efficiencies was within the range of measurement uncertainties in most cases, model improvements are expected to be possible concerning the heat capacitance modelling in cycling on/off operation as well as influences of start and stop behaviour on the overall efficiency. It is found that electricity consumption during cycling on/off operation of small pellets or oil space heating boilers may have a significant influence on the overall energy balance of these units. This influence increases strongly with decreasing heat load and increasing number of on/off cycles.

  • 78. Haller, M.
    et al.
    Yazdanshenas, E.
    Andersen, E.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Streicher, W.
    Furbo, S.
    A method to determine stratification efficiency of thermal energy storage processes independently from storage heat losses2010Inngår i: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 84, nr 6, s. 997-1007Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A new method for the calculation of a stratification efficiency of thermal energy storages based on the second law of thermodynamics is presented. The biasing influence of heat losses is studied theoretically and experimentally. Theoretically, it does not make a difference if the stratification efficiency is calculated based on entropy balances or based on exergy balances. In practice, however, exergy balances are less affected by measurement uncertainties, whereas entropy balances can not be recommended if measurement uncertainties are not corrected in a way that the energy balance of the storage process is in agreement with the first law of thermodynamics. A comparison of the stratification efficiencies obtained from experimental results of charging, standby, and discharging processes gives meaningful insights into the different mixing behaviors of a storage tank that is charged and discharged directly, and a tank-in-tank system whose outer tank is charged and the inner tank is discharged thereafter. The new method has a great potential for the comparison of the stratification efficiencies of thermal energy storages and storage components such as stratifying devices.

  • 79.
    Haller, Michel
    et al.
    Institut für Solartechnik SPF, Hochschule für Technik HSR.
    Carbonell, Dani
    Institut für Solartechnik SPF, Hochschule für Technik HSR.
    Bertram, Erik
    Institut für Solarenergieforschung Hameln ISFH.
    Heinz, Andreas
    Institut für Wärmetechnik, Technische Universität Graz.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    System simulations2015Inngår i: Solar and Heat Pump Systems for Residential Buildings / [ed] Jean-Christophe Hadorn, John Wiley & Sons, 2015, 1, s. 274-Kapittel i bok, del av antologi (Fagfellevurdert)
  • 80.
    Hathout, Ahmed
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    A Comprehensive PV Systems Installation Guide and Designing a Roof-Based PV System as a Demonstration System for Troubleshooting Errors in PV systems Installations2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The purpose of the thesis was to make a comprehensive guide for PV systems installers and engineers, using the best practices and following the applicable regulations and standards for the mechanical and electrical installations of PV systems. The guide includes all the different aspects of a PV system installation including different types of roofs and mounting structures, fire safety, height safety and fall protection, installation precautions, electrical and mechanical installations, safety gears and finally system commissioning.

    The guide was developed by reviewing the various standards and best practices deployed in various countries that are pioneers in PV installations as Germany, UK and the US in the period from 2006-2018.

     

    A troubleshooting errors scheme was conducted to help installers track down operational faults in a PV system. Installers will be able to identify problems of old or newly installed PV systems according to few procedures to resolve operational problems.

     

    In addition, a PV system was designed on the rooftop of Högskolan Dalarna in Sweden. The system will be used as a learning platform for installers in a course that will be introduced on the University’s campus, aimed at educating installers on PV systems installations. The designed system mainly focuses on flat and pitched roofs installations.

    The system was designed with the main priority to benefit installers working on and installing the system. Performance ratio and energy yield of the system were not emphasized when designing the system. It was specifically designed to match the objectives of the university’s installer’s course to be conducted on the campus. The designed system consists of two sub-arrays with two different mounting structures. The first one was a pitched roof mounting structure installed on a small hut on the university’s rooftop, and the second sub-array was a ballast mounting system directly situated on the roof surface with no penetrations to its surface. The system was designed on Sketchup software as a 3D model, simulated in PVsyst for energy yield forecast and losses evaluations, drawn as a single line electrical diagram on AutoCAD and lastly, a bill of materials was conducted with all the necessary components and parts to install the system on the rooftop.

     

    Results from the simulated system shows a steep drop in energy yield during the winter months, energy losses due to shading effects of approximately 5 % and minimal other system and cables losses were recorded.

     

    A study visit for a pitched roof PV system installation to be carried out by a group of six Swedish students was conducted. A discussion about the installation procedure, major mistakes and lack of practical knowledge by the engineering students were analyzed.

    Possessing knowledge of PV systems installations is of great importance not only to installers, but to solar design engineers. It is a necessity that engineers poses the fundamentals of installing a PV system and follow the applicable standards and best practices during systems design and execution.

  • 81.
    Hathout, Ahmed
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    A Comprehensive PV Systems Installation Guide and Designinga Roof-Based PV System as a Demonstration System for Troubleshooting Errors in PV systems Installations2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The purpose of the thesis was to make a comprehensive guide for PV systems installers and engineers, using the best practices and following the applicable regulations and standards for the mechanical and electrical installations of PV systems. The guide includes all the different aspects of a PV system installation including different types of roofs and mounting structures, fire safety, height safety and fall protection, installation precautions, electrical and mechanical installations, safety gears and finally system commissioning.

    The guide was developed by reviewing the various standards and best practices deployed in various countries that are pioneers in PV installations as Germany, UK and the US in the period from 2006-2018.

    A troubleshooting errors scheme was conducted to help installers track down operational faults in a PV system. Installers will be able to identify problems of old or newly installed PV systems according to few procedures to resolve operational problems.

    In addition, a PV system was designed on the rooftop of Högskolan Dalarna in Sweden. The system will be used as a learning platform for installers in a course that will be introduced on the University’s campus, aimed at educating installers on PV systems installations. The designed system mainly focuses on flat and pitched roofs installations.

    The system was designed with the main priority to benefit installers working on and installing the system. Performance ratio and energy yield of the system were not emphasized when designing the system. It was specifically designed to match the objectives of the university’s installer’s course to be conducted on the campus.

    The designed system consists of two sub-arrays with two different mounting structures. The first one was a pitched roof mounting structure installed on a small hut on the university’s rooftop, and the second sub-array was a ballast mounting system directly situated on the roof surface with no penetrations to its surface. The system was designed on Sketchup software as a 3D model, simulated in PVsyst for energy yield forecast and losses evaluations, drawn as a single line electrical diagram on AutoCAD and lastly, a bill of materials was conducted with all the necessary components and parts to install the system on the rooftop.

    Results from the simulated system shows a steep drop in energy yield during the winter months, energy losses due to shading effects of approximately 5 % and minimal other system and cables losses were recorded.

    A study visit for a pitched roof PV system installation to be carried out by a group of six Swedish students was conducted. A discussion about the installation procedure, major mistakes and lack of practical knowledge by the engineering students were analyzed.

    Possessing knowledge of PV systems installations is of great importance not only to installers, but to solar design engineers. It is a necessity that engineers poses the fundamentals of installing a PV system and follow the applicable standards and best practices during systems design and execution.

  • 82. He, W.
    et al.
    Zhang, Xingxing
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Solar Heating, Cooling and Power Generation — Current Profiles and Future Potentials2019Inngår i: Advanced Energy Efficiency Technologies for Solar Heating, Cooling and Power Generation / [ed] Xudong ZhaoXiaoli Ma, Springer, 2019, s. 31-78Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    Due to the large amount of consumption of the fossil fuels, the ecological environment has suffered serious pollution and damage. Solar power technologies provide the best solution to the current energy and environment issues. In past decades, global solar thermal capacity increased rapidly, and now it has been used worldwide to provide heating, cooling and power generation. However, after years of development, solar energy utilization technology still faces problems such as low efficiency, high cost, difficulty in energy storage and unstable energy supply, which have been seriously restricting its applications. This chapter briefly summarizes the concept and classification of solar heating, cooling and power generation. Furthermore, some technology development and potential applications relating to solar heating, cooling and power generation are discussed.

  • 83. He, Wei
    et al.
    Hong, Xiaoqiang
    Zhao, Xudong
    Zhang, Xingxing
    University of Hull.
    Shen, Jinchun
    Ji, Jie
    Operational performance of a novel heat pump assisted solar facade loop-heat-pipe water heating system2015Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 146, s. 371-382Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper aims to present an investigation into the operational performance of a novel heat pump assisted solar façade loop-heat-pipe (LHP) water heating system using both theoretical and experimental methods. This involved (1) development of a computer numerical model; (2) simulation of the operational performance of the system by using the model; (3) test rig construction; and (4) dedicated experiment for verification of the model. It was found that the established model is able to predict the operational performance of the system at a reasonable accuracy. Analyses of the research results indicated that under the selected testing conditions, the average thermal efficiency of the LHP module was around 71%, much higher than that of the loop heat pipe without heat pump assistance. The thermal efficiency of the LHP module grew when the heat pump was turned-on and fell when the heat pump was turned-off. The water temperature remained a steadily growing trend throughout the heat pump turned-on period. Neglecting the heat loss of the water tank, the highest coefficient of the performance could reach up to 6.14 and its average value was around 4.93. In overall, the system is a new façade integrated, highly efficient and aesthetically appealing solar water heating configuration; wide deployment of the system will help reduce fossil fuel consumption in the building sector and carbon emission to the environment.

  • 84. He, Wei
    et al.
    Hong, Xiaoqiang
    Zhao, Xudong
    Zhang, Xingxing
    University of Hull.
    Shen, Jinchun
    Ji, Jie
    Theoretical investigation of the thermal performance of a novel solar loop-heat-pipe facade-based heat pump water heating system2014Inngår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 77, s. 180-191Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The aim of the paper was to present a dedicated theoretical investigation into the thermal performance of a novel solar loop-heat-pipe façade based heat pump water heating system. This involved thermo-fluid analyses, computer numerical model development, the model running up, modelling result analyses and conclusion. An energy balance network was established on each part and the whole range of the system to address the associated energy conversion and transfer processes. On basis of this, a computer numerical model was developed and run up to predict the thermal performance of such a system at different system configurations, layouts and operational conditions. It was suggested that the loop heat pipes could be filled with either water, R134a, R22 or R600a; of which R600a is the favourite working fluid owing to its relatively larger heat transfer capacity and positive pressure in operation. Variations in the system configuration, i.e., glazing covers, heat exchangers, would lead to identifiable differences in the thermal performance of the system, represented by the thermal efficiency and COP. Furthermore, impact of the external operational parameters, i.e., solar radiation and ambient air temperature, to the system's thermal performance was also investigated. The research was based on an innovative loop-heat-pipe façade and came up with useful results reflecting the thermal performance of the combined system between the façade and heat pump. This would help promote development and market penetration of such an innovative solar heating technology, and thus contribute to achieving the global targets in energy saving and carbon emission reduction.

  • 85. He, Wei
    et al.
    Zhang, Gan
    Zhang, Xingxing
    University of Nottingham.
    Ji, Jie
    Li, Guiqiang
    Zhao, Xudong
    Recent development and application of thermoelectric generator and cooler2015Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 143, s. 1-25Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Energy crisis and environment deterioration are two major problems for 21st century. Thermoelectric device is a promising solution for those two problems. This review begins with the basic concepts of the thermoelectric and discusses its recent material researches about the figure of merit. It also reports the recent applications of the thermoelectric generator, including the structure optimization which significantly affects the thermoelectric generator, the low temperature recovery, the heat resource and its application area. Then it reports the recent application of the thermoelectric cooler including the thermoelectric model and its application area. It ends with the discussion of the further research direction.

  • 86.
    Heier, Johan
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Energieffektivisering i småhus i Dalarna2013Rapport (Annet vitenskapelig)
    Abstract [sv]

    En undersökning av byggnadsbeståndet i landet visar att permanentbodda småhus står för 70 % av det totala antalet byggnader, eller 54 % av den totala byggnadsarean. Inkluderas även fritidshus är siffran uppe i 92 % sett till antalet byggnader och det är tydligt att energieffektivisering i våra småhus spelar en nyckelroll i möjligheterna att nå uppsatta mål för minskad energianvändning i byggnadssektorn. Dalarna är ett län med en större andel småhus än genomsnittet för hela landet, med en stor mängd småhus byggda fram till 1960, samt mellan 1971-1980. Några anledningar att fokusera energieffektiviseringsarbete på småhusen byggda mellan 1971-1980 är dels att det är den åldersgrupp som innefattar näst flest hus (näst efter småhus uppförda fram till 1940) och dels att dessa småhus är tillräckligt nya för att innehålla många orenoverade objekt. Åldersspannet är även relativt snävt (endast 10 år) vilket innebär att byggtekniken som använts i dessa hus troligtvis är relativt lika. Å andra sidan förbrukar de äldre småhusen betydligt mer energi (köpt energi per m2) vilket är en anledning att titta även på äldre hus då potentialen för minskad energianvändning kan vara högre trots att de kanske redan är renoverade i en större utsträckning.

  • 87.
    Heier, Johan
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik. KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Energieffektivisering via termisk energilagring2013Inngår i: Energi & miljö, ISSN 1101-0568, nr 10, s. 63-66Artikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
    Abstract [sv]

    Uppsatta mål för kraftigt minskad mängd köpt energi inom byggnadssektorn öppnar upp för alternativa tekniker när både befintliga och nya byggnader ska energieffektiviseras. Genom att lagra värme och/eller kyla kan tillgänglig energi flyttas i tid och bidra till energieffektivisering genom t.ex. en ökad andel förnyelsebar energi eller minskad toppeffekt.

  • 88.
    Heier, Johan
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Energirenovering av småhus - en förstudie2018Rapport (Annet vitenskapelig)
    Abstract [sv]

    Bostadsbeståndet i Sverige har ett stort renoveringsbehov, inte minst våra småhus. Renoveringsbehovet består inte enbart i underhåll av byggnaderna, utan även om energieffektivisering för att kunna nå de mål som finns uppsatta. Här räcker det inte enbart med åtgärder på värmesystemet, något som speciellt är vanligt bland småhusen i form av byte till värmepump, utan större insatser även på klimatskalet. För flerbostadshus har det gjorts stora och breda satsningar på området medan det för småhus endast förekommer mindre, riktade satsningar. Detta kan delvis bero på svårigheten att nå ut till de ca två miljoner småhusägare som finns i landet, som med olika motiv och önskemål (även inom samma bostad), ekonomiska förutsättningar och intresse för energirenovering bildar en väldigt diversifierad grupp.

     Högskolan Dalarna har tidigare gjort ett antal studier om energirenovering av villor med olika ingångar, men ingen holistisk studie. Denna studie syftar till att göra en kunskapssammanställning om området samt att föra en dialog med utvalda aktörer under seminarier och workshops för att reda ut hur arbetet med utveckling av energirenovering för småhus kan dras vidare på nationell nivå.

     Studien visar att det finns en stor potential för energirenovering i småhusbeståndet, men också att det finns många hinder som måste överkommas. Dessa hinder är till en mindre del tekniska utan istället är andra problemområden som finansiering, brist på lämpliga styrmedel, kunskapsbrist bland olika involverade aktörer, bestämmelser m.m. väsentliga. Studien har inte kunnat hitta goda exempel där man lyckats hitta fungerande strukturer som kan täcka in den bredd som krävs för att uppmuntra småhusägare att genomföra energirenoveringar som är tillräckligt omfattande. Därtill är mängden aktörer som måste involveras vid en större energirenovering så stor att det krävs en hög kunskapsnivå, ett brett kontaktnät samt ett stort engagemang; något som få småhusägare har. Det finns heller ingen tydlig aktörsgrupp som vill ta hand om denna typ av totalentreprenad för villor.

     Den samlade bedömningen hos de nyckelaktörer som varit involverade i förstudiearbetet är att det krävs en kraftansamling med en bred ansats för att småhussektorn signifikant ska kunna bidra till uppsatta mål för energieffektivisering i byggnader. Satsningen måste även vara långsiktig med mång- och tvärvetenskaplig forskning tillsammans med utvecklingssatsningar mot branschen för att kunna ligga till grund för implementering av relevanta och effektiva styrmedel och kunskapshöjande åtgärder.

  • 89.
    Heier, Johan
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Fjärrkyla från naturgasförångning vid SSAB Borlänge: Förstudie om möjligheter för kyla till bandy- och datalagringshall2014Rapport (Annet vitenskapelig)
    Abstract [sv]

    Högskolan Dalarna har i samråd med Borlänge Energi utfört en förstudie angående möjligheten att utnyttja kyla från förångningsstationen av naturgas vid SSAB Borlänge för fjärrkyla till närliggande, nyetablerade, kunder i form av en bandyhall samt en datalagringshall. En potentiell plats för placering är Savelgärdet, som ligger i nära anslutning till kylproduktionen på SSAB.

    Överskottet av kyla från SSAB är väldigt beroende av produktionstakten vilket gör att det är många avbrott i varierande längd. En uppskattning baserad på 2013 års driftdata visar att naturgasförångningen skulle kunna generera cirka 8-9 GWh kyla vid 4 °C och en medeleffekt på 1 MW. Till detta tillkommer kyla från förångning av syrgas.

    Förstudien visar att kylbehovet för en bandyhall är begränsat vid de temperaturer på kyla som kommer att kunna produceras vid SSAB. En datalagringshall å andra sidan kan, beroende på storlek, potentiellt utnyttja all kyla som produceras. Här blir även återvinning av värme en relevant fråga. En annan intressant diskussion är hur fjärrkyla från SSAB samt de kylmaskiner som kommer att krävas vid en bandyhall samt en datalagringshall kan kombineras för att få en sådan optimal produktion av kyla som möjligt. Detta blir än mer intressant ifall Borlänge Energi i framtiden väljer att expandera ett fjärrkylsystem till övriga kunder runt Borlänge Centrum, eftersom man kan tänka sig att kylmaskinerna vid en bandyhall och datalagringshall kan användas som en del i hela fjärrkylsystemet och Borlänge Energi inte ensamt behöver investera i reservkapacitet.

  • 90.
    Heier, Johan
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Paketering av energisparåtgärder i småhus2013Rapport (Annet vitenskapelig)
    Abstract [sv]

    Ska energimålen med halvering av energianvändningen kunna nås i länet måste småhusägare och ägare av mindre flerbostadshus övertygas om nyttan och möjligheter med att energieffektivisera i egna byggnader. Genom att använda en metod för paketering av energisparåtgärder kan byggnader energirenoveras på ett effektivt sätt och energianvändningen kan på så sätt minimeras.

    BELOK Totalprojekt är en metod för energieffektivisering i kommersiella byggnader genom renovering med åtgärdspaket. Metoden har även använts för flerbostadshus och uppgiften i den här rapporten är att undersöka ifall samma metod kan vara lämplig att använda även för småhus. Resultaten visar att metoden mycket väl kan användas även för småhus, men att vissa anpassningar är nödvändiga för att småhusägare ska kunna relatera till resultatet. Vid renovering i småhus kan många olika aktörer vara inblandade beroende på hur småhusägaren väljer att utföra en renovering. Om småhusägaren själv gör huvuddelen av arbetet är det lämpligt att Energikalkylen eller motsvarande kan användas för att göra en förenklad energianalys av byggnaden för att sedan föra över data till BELOK Totalverktyg, där det ekonomiska utfallet för renoveringspaket illustreras. Uppföljningen efter slutförd renovering är något som till exempel energibolag skulle kunna erbjuda tjänster för. Om småhusägaren väljer att anlita en energikonsult för den initiala analysen av byggnaden kan BELOK Totalprojekt användas mer i sin helhet men detta innebär förstås en högre kostnad för småhusägaren.

    För att öppna upp för fler möjligheter för småhusägare att totalrenovera är det viktigt att även involvera banksektorn för att diskutera ett upplägg för lån till energieffektivisering. Här kan även styrmedel av karaktären statliga lånegarantier eller ROT-avdrag för energieffektivisering vara aktuella att ta upp till diskussion. Slutligen är kommunikation med småhusägarna väldigt viktig och här är aktörer som redan idag har kontakt med småhusägare centrala. Två sådana aktörer är energibolag samt Villaägarnas Riksförbund.

  • 91.
    Heier, Johan
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik. KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Martin, Viktoria
    Energy Efficiency through Thermal Energy Storage - Evaluation of the Possibilities for the Swedish Building Stock, Phase 12010Inngår i: Clima2010, Antalya, Turkiet, 2010Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    As a first step in assessing the potential of thermal energy storage in Swedish buildings, the current situation of the Swedish building stock and different storage methods are discussed in this paper. Overall, many buildings are from the 1960’s or earlier having a relatively high energy demand, creating opportunities for large energy savings. The major means of heating are electricity for detached houses and district heating for multi dwelling houses and premises. Cooling needs are relatively low but steadily increasing, emphasizing the need to consider energy storage for both heat and cold. The thermal mass of a building is important for passive storage of thermal energy but this has not been considered much when constructing buildings in Sweden. Instead, common ways of storing thermal energy in Swedish buildings today is in water storage tanks or in the ground using boreholes, while latent thermal energy storage is still very uncommon.

  • 92.
    Heier, Johan
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik. KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Martin, Viktoria
    Thermal energy storage in Swedish single family houses: a case study2012Inngår i: InnoStock The 12th International Conference on Energy Storage: Book of Abstract, 2012Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    In a Nordic climate, space heating (SH) and domestic hot water (DHW) used in buildings constitute a considerable part of the total energy use in the country. For 2010, energy used for SH and DHW amounted to almost 90 TWh in Sweden which corresponds to 60 % of the energy used in the residential and service sector, or almost 24 % of the total final energy use for the country.

    Storing heat and cold with the use of thermal energy storage (TES) can be one way of increasing the energy efficiency of a building by opening up possibilities for alternative sources of heat or cold through a reduced mismatch between supply and demand. Thermal energy storage without the use of specific control systems are said to be passive and different applications using passive TES have been shown to increase energy efficiency and/or reduce power peaks of systems supplying the heating and cooling needs of buildings, as well as having an effect on the indoor climate. Results are however not consistent between studies and focus tend to be on the reduction of cooling energy or cooling power peaks. In this paper, passive TES introduced through an increased thermal mass in the building envelope to two single family houses with different insulation standard is investigated with building energy simulations. A Nordic climate is used and the focus of this study is both on the reduction of space heating demand and space heating power, as well as on reduction of excess temperatures in residential single family houses without active cooling systems. Care is taken to keep the building envelope characteristics other than the thermal mass equal for all cases so that any observations made can be derived to the change in thermal mass.

    Results show that increasing the sensible thermal mass in a single family house can reduce the heating demand only slightly (1-4 %) and reduce excess temperatures (temperatures above 24 degrees C) by up to 20 %. Adding a layer of PCM (phase change materials) to the light building construction can give similar reduction in heating demand and excess temperatures, however the phase change temperature is important for the results.

  • 93.
    Heier, Johan
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik. KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Sotnikov, Artem
    Ponomarova, Ganna
    Evaluation of a high temperature solar thermal seasonal borehole storage2011Inngår i: ISES Solar World Congress, Kassel, 2011Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    A solar thermal system with seasonal borehole storage for heating of a residential area in Anneberg, Sweden, approximately 10 km north of Stockholm, has been in operation since late 2002. Originally, the project was part of the EU THERMIE project “Large-scale Solar Heating Systems for Housing Developments” (REB/0061/97) and was the first solar heating plant in Europe with borehole storage in rock not utilizing a heat pump. Earlier evaluations of the system show lower performance than the preliminary simulation study, with residents complaining of a high use of electricity for domestic hot water (DHW) preparation and auxiliary heating. One explanation mentioned in the earlier evaluations is that the borehole storage had not yet reached “steady state” temperatures at the time of evaluation. Many years have passed since then and this paper presents results from a new evaluation. The main aim of this work is to evaluate the current performance of the system based on several key figures, as well as on system function based on available measurement data. The analysis show that though the borehole storage now has reached a quasi-steady state and operates as intended, the auxiliary electricity consumption is much higher than the original design values largely due to high losses in the distribution network, higher heat loads as well as lower solar gains.

  • 94.
    Heier, Johan
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Bergdahl, Martin
    Högskolan Dalarna, Akademin Industri och samhälle, Byggteknik.
    Börjesson, Petter
    Energiexpertis.
    Paketrenovering i småhus med BELOK Totalmetodik: Resultat som beslutsunderlag vid finansiering med energilån?2014Rapport (Annet vitenskapelig)
    Abstract [sv]

    Syftet med denna studie är att illustrera en metod för att hjälpa ägare av mindre fastigheter att nå en högre energieffektiviseringsgrad vid renovering genom paketering av åtgärder. Metoden som används, BELOK Totalprojekt, utvecklades ursprungligen för användning ilokaler och kommersiella byggnader, men vår ambition i Dalarna är att visa metodens tillämpning även för mindre fastigheter som småhus. Det som avgör fastighetsägarensbeslut om åtgärdspaket är ofta dels osäkerheten kring vad som är rätt åtgärder men också kring kostnaden och lönsamheten med investerat kapital. Metoden som visas i denna rapport kan avsevärt minska dessa osäkerheter och på så vis även underlätta vid kreditgivares bedömning när eventuella lån ska beviljas.

    I den här studien har fyra typiska småhus av olika ålderskategori genomgått en energianalys för att identifiera tekniskt möjliga åtgärder för att minska energianvändningen. Dessa åtgärder har sedan satts samman till ett antal åtgärdspaket för att slutligen lönsamhetsberäknas med hjälp av BELOK Totalverktyg. Resultaten presenteras i form av internräntediagram, vilket ger ett mått på paketets lönsamhet, årsbehov av köpt energi och primärenergi före och efter åtgärderna samt slutligen årlig energikostnad för varje paket.

    Resultatet visar att det går att göra lönsamma åtgärdspaket som når en halvering av energianvändningen (både köpt energi och primärenergi) i 2 av 4 studerade hus. De två hus som klarar av att lönsamt halvera energianvändningen är båda uppvärmda med el utan värmepump eller energiåtervinning på ventilationen. Det ena huset där en lönsam halvering inte är möjlig är uppvärmt med fjärrvärme och det andra är ett nyare hus som är utrustat med värmeåtervinning på ventilationsluften. Om man har ett relativt billigt uppvärmningssätt (fjärrvärme kontra el) eller om byggnaden redan har en låg energianvändning är det svårt att nå en lönsam halvering. Det går dock att hitta mindre åtgärdspaket som är lönsamma och samtidigt innebär en betydande energieffektivisering.

    En annan slutsats från resultaten är att det är relativt enkelt att göra stora besparingar i både köpt energi och primärenergi i ett eluppvärmt hus genom att installera någon form av värmepump. Att installera en värmepump i ett hus uppvärmt med fjärrvärme kan ge en stor besparing i köpt energi, men ger enbart en måttlig besparing i primärenergi. Att byta från el till förnyelsebar energikälla (pellets i detta fall) ger i ett av exemplen en nästan oförändrad användning av köpt energi medan man når en halvering av primärenergianvändningen. Det är alltså viktigt att poängtera att en kostnadseffektivisering med de metoder som används i rapporten inte nödvändigtvis leder till en energieffektivisering i ett större sammanhang, där primärenergi vägs in.

    Denna rapport är resultatet från Lågan-projektet 2014:12 ”BELOK S – exempel påtillämpning i befintliga småhus”. Projektet är finansierat av Lågan (och därmed indirekt av Energimyndigheten), ByggDialog Dalarna samt Högskolan Dalarna genom Energi- och miljökompetenscentrum, EMC. Även tre banker har bidragit med egen tid i form av deltagande i intervjuer samt synpunkter och dessa är Swedbank Falun, Länsförsäkringar bank Dalarna samt Leksands sparbank.

  • 95.
    Heier, Johan
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Lorenz, Klaus
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Poppi, Stefano
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    SOHOT: Solvärme för hotell2014Rapport (Annet vitenskapelig)
    Abstract [sv]

    Vid dimensionering av ett solvärmesystem av den typ som diskuteras i rapporten är varmvattenförbrukningen avgörande för systemets storlek. Litteraturstudien visar dock att varmvattenförbrukningen varierar kraftigt mellan olika typer av hotell samt vilken beläggningsgrad dessa har. För ett normalt ”medel”-hotell kan varmvattenförbrukningen uppskattas till 70 liter vid 60 grader per person och dag. För ett enklare hotell (typ vandrarhem) är förbrukningen ungefär hälften och för ett lyxhotell dubbelt så stor (35 respektive 140 liter per person och dag). Den högsta förbrukningen äger rum under två toppar, en på morgonen och en på kvällen. Under en av dessa toppar används ca 18-30 % av dygnets varmvatten under en timme. Beläggningsgraden är typiskt som högst sommartid och lägre vintertid, men beror förstås på hotellets målgrupp.

     

    Med detta som utgångspunkt har simuleringar för Stockholm och Malaga utförts i Polysun, där tre systemstorlekar samt två kvalitetsklasser av solfångare har använts. Resultaten visar att det går att nå en solandel på 50-75 % av tappvattenlasten i Stockholm och 60-90 % av tappvattenlasten för Malaga. Tack vare den högre solinstrålningen på Malaga kan systemet dimensioneras hälften så stort där. En känslighetsanalys över tappvattenlasten, där samma tappvattenlast som tidigare fast med jämn fördelning över årets månader används, visar att ett system i Nordiskt klimat får en lägre solandel medan systemet i Malaga inte påverkas lika mycket. Samma system i Malaga är alltså mindre känsligt för förändringar i tappvattenlastprofilen.

     

    Aktörsanalysen visar att det finns ett flertal företag i Dalaregionen som kan tänkas vara lämpliga att ingå i en projektgrupp med syfte att ta fram och utveckla en prototyp för konceptet solvärme till hotell. För att välja ut lämpliga samarbetspartners är det en rekommendation att kontakta Teknikdalen i Borlänge. En närmare diskussion med Teknikdalen kan ge en tydligare bild av vilka typer av aktörer som krävs för projektet samt även hur finansieringen kan lösas. Något som bör undersökas vidare är möjligheten till finansiering för ett demonstrationsprojekt, t.ex. lokalt i anknytning till Teknikdalen. En annan möjlig finansiering som verkar vara på gång är en utlysning relaterad till demonstrationsprojekt utomlands. Utlysningen är en enligt kontakt med Teknikdalen en fortsättning på Demomiljö (Sida/Tillväxtverket) dock finns inga detaljer tillgängliga i dagsläget.

  • 96.
    Henning, Annette
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Klimatsmart villavärme?: Solvärme, nya byggregler och möjligheten att förändra2010Bok (Annet vitenskapelig)
    Abstract [sv]

    Är vi på väg mot klimatsmartare, resurssnålare och flexiblare uppvärmning av nybyggda småhus? Denna fråga ställer sig fem forskare vid Centrum för solenergiforskning SERC. En socialantropolog, en statsvetare och tre energiteknikforskare beskriver här tillsammans dagsläget, samt pekar på möjligheter och svårigheter med att åstadkomma en förändring i denna riktning. Den senaste revideringen av Boverkets byggregler uppmärksammas särskilt, liksom möjligheten att utnyttja solfångare och ackumulatortank för att reducera mängden inköpt primärenergi samtidigt som man bevarar de boendes valfrihet.

  • 97.
    Henning, Annette
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Making Energy Interventions more Effective: Situation, Interaction, and Precondition2015Inngår i: International Journal of Humanities and Social Science, ISSN 2220-8488, E-ISSN 2221-0989, Vol. 5, nr 9, s. 46-54Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A main purpose of this paper is to propose to policy makers, building professionals, and other non-social scientists a way to make energy interventions more culturally informed and, thereby, more effective. The case study on house purchasers gives an ample illustration of the richer results that can be achieved by paying attention to three aspects of energy efficiency initiatives: the contexts and situations of choice in each particular case, the interaction among relevant social actors, and the culture-specific preconditions for choice. Research on how purchasers of new pre-fabricated houses in Sweden choose their heating system show how such decisions tend to fall between two stools. Furthermore, the organizational structure of housing companies frames house purchasers' decision making. An important result is that energy saving or conversion measures must be promoted at an early stage amongst those who plan and construct buildings (rather than later amongst dwellers and energy end users).

  • 98. Hu, J
    et al.
    Chen, W
    Yin, Y
    Li, Y
    Yang, D
    Wang, H
    Zhang, Xingxing
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Electrical-thermal-mechanical properties of multifunctional OPV-ETFE foils for transparent membrane buildings2018Inngår i: Polymer testing, ISSN 0142-9418, E-ISSN 1873-2348, Vol. 66, s. 394-402Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    ETFE (ethylene tetrafluoroethylene) foils integrated organic photovoltaic cells (OPV) have attracted considerable attention in recent years due to the achievement of sustainability. As building materials, multifunctional OPV-ETFE foils could produce electricity, store thermal energy and possess structural capability. In this case, electrical, thermal and mechanical properties coexist and influence each other due to photovoltaic/thermal effects. Understanding the fundamental mechanism is significant to analyze and design corresponding structures. This paper concerns coupled properties of OPV-ETFE specimens with controlled experiments. One-parameter and two-parameter analysis of two typical specimens are performed to investigate essential properties. Experimental observations show that within normal working conditions, electrical properties are relatively independent but that thermal-mechanical properties are related to each other. Yield stress, yield strain and elastic modulus are calculated from stress-strain curves; these mechanical properties are comparable with those of original ETFE foils at the same temperature. It is concluded from temperature-stress curves that yield point has a critical effect on temperature-stress correlation and that mechanical properties of double OPV specimens are better than those of single OPV specimens. Generally, these mechanical properties could provide basic insights into evaluation of energetic performance and structural behavior of transparent membrane buildings.

  • 99. Huang, P
    et al.
    Fan, C
    Zhang, Xingxing
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Wang, J
    A hierarchical coordinated demand response control for buildings with improved performances at building group2019Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 242, s. 684-694Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Demand response control is one of the common means used for building peak demand limiting. Most of the existing demand response controls focused on single building’s performance optimization, and thus may cause new undesirable peak demands at building group, imposing stress on the grid power balance and limiting the economic savings. A few latest studies have demonstrated the potential benefits of demand response coordination, but the proposed methods cannot be applied in large scales. The main reason is that, for demand response coordination of multiple buildings, associated computational load and coordination complexity, increasing exponentially with building number, are challenges to be solved. This study, therefore, proposes a hierarchical demand response control to optimize operations of a large scale of buildings for group-level peak demand reduction. The hierarchical control first considers the building group as a ‘virtual’ building and searches the optimal performance that can be achieved at building group using genetic algorithm. To realize such optimal performance, it then coordinates each single building’s operation using non-linear programming. For validations, the proposed method has been applied on a case building group, and the study results show that the hierarchical control can overcome the challenges of excessive computational load and complexity. Moreover, in comparison with conventional independent control, it can achieve better performances in aspects of peak demand reduction and economic savings. This study provides a coordinated control for application in large scales, which can improve the effectiveness and efficiency in relieving the grid stress, and reduce the end-users’ electricity bills.

  • 100.
    Huang, Pei
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Copertaro, Benedetta
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Zhang, Xingxing
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Shen, Jingchun
    Högskolan Dalarna, Akademin Industri och samhälle, Byggteknik.
    Löfgren, Isabelle
    Rönnelid, Mats
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Fahlen, Jan
    Andersson, Dan
    Svanfeldt, Mikael
    A review of data centers as prosumers in district energy systems: Renewable energy integration and waste heat reuse for district heating2019Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    As large energy prosumers in district energy systems, on the one hand, data centers consume a large amount of electricity to ensure the Information Technologies (IT) facilities, ancillary power supply and cooling systems work properly; on the other hand, data centers produce a large quantity of waste heat due to the high heat dissipation rates of the IT facilities. To date, a systematic review of data centers from the perspective of energy prosumers, which considers both integration of the upstream green energy supply and downstream waste heat reuse, is still lacking. As a result, the potentials for improving data centers’ performances are limited due to a lack of global optimization of the upstream renewable energy integration and downstream waste heat utilization. This study is intended to fill in this gap and provides such a review. In this regard, the advancements in different cooling techniques, integration of renewable energy and advanced controls, waste heat utilization and connections for district heating, real projects, performance metrics and economic, energy and environmental analyses are reviewed. Based on the enormous amount of research on data centers in district energy systems, it has been found that: (1) global controls, which can manage the upstream renewable production, data centers’ operation and waste heat generation and downstream waste heat utilization are still lacking; (2) regional climate studies represent an effective way to find the optimal integration of renewable energy and waste heat recovery technologies for improving the data centers’ energy efficiency; (3) the development of global energy metrics will help to appropriately quantify the data center performances.

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