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  • 51.
    Emos, Maen
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Design and measurements on a PV/Wind hybrid system2006Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    There are several purposes of this thesis work and it achieves different types of goals. It starts from investigating, sizing, and building ending with measurements and comparison; the typical aims are listed below. • Investigation of the available components of the old wind stand alone system located on the top of Högskolan Dalarna (Borlänge) main building and how these components can be used in a new PV/wind hybrid System. • Size and design a PV/wind hybrid system by a computer simulation program; for Borlänge climate, with a constant load. • Building the designed PV/wind hybrid system on the same location of old wind stand alone system. The construction should be in a way that can be used for future education. • Installing the required measurement equipments. • Measurements on the built system. • Comparison between the measured and simulated results.

  • 52.
    Estevez, Nicolas
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Photovoltaic Power in the Swedish Grid: How to Deal with Solar Electricity Overproduction in the Future2007Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Due to the continued growth of installed area of Photovoltaic (PV) panels, Sweden will face a problem with electricity overproduction when PV panel production accounts for about 9% of total yearly electricity demand. Although this scenario might be over a decade away from happening it is important to look ahead now and make sure that our current practices and standards do not lead us into trouble in the future. This thesis explores the issue of Photovoltaic electricity overproduction in Sweden. The methodology of this work includes analyzing hourly weather data measured in five Swedish cities over several years and hourly electricity demand data of whole Sweden. A solar simulation program was written that would use the hourly weather data and calculate hourly insolation on tilted surfaces. The solar simulator output was used to calculate the area of PV when overproduction becomes a problem in Sweden and to explore the effect of surface tilt and orientation on yearly usable electricity production when the PV area grows beyond that point. This area is referred to as A0 in this text, and the best guess for Sweden was about 128 million square meters. Some scenarios with an installed PV area equal to different multiples of A0 were studied. Options of varying tilt and orientation angle could be evaluated to see which one would result in the highest yearly output. For example when the installed area equals 2 x A0 the highest output from the PV panels result from pointing the panels in the same way as with no overproduction. Only a 6% overproduction loss is suffered from doubling the Max Area of Zero Overproduction and PV would be able to cover about 17% of the yearly Swedish electric demand. Beyond doubling of A0 the angles become less important. This is because as the overproduction becomes higher for the optimal angles the non-optimum angles which are able to avoid overproduction will still have comparable yield. However the best yields are generated by the optimal angles found at 1 x A0. In Sweden the PV market can continue to grow until it covers about 15 to 17 percent of the annual electric demand before starting to suffer significant losses from electricity overproduction. In order to maximize yearly output the overproduction must be accepted and as PV continues to grow perhaps grid energy storage should be implemented.

  • 53.
    Feng, Zhang
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Studying Six Photovoltaic Electric Vehicle Cars with a Photovoltaic Standalone Station2006Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    This research is focused to design a type of solar photovoltaic electric vehicle for Shenyang International Horticulture Exposition and a photovoltaic standalone station matched for the same type of six vehicles. Since Shenyang’s latitude is 42°N, the solar vehicle and PV station sometimes have to work in low insolation. Absolutely cost-efficiency is necessary. The m-Si solar cell has similar characteristics to single crystal silicon. It has 11-14% industrial efficiency, good stability and over 20-years lifetime. Additionally it is cheaper and operating better under low insolation than single crystal silicon, and its efficiency is much higher than amorphous silicon solar cell, so it is the best choice used in this project. The gel battery has the electrolyte mixed with H2SO4 solution and Si sol. Its lifetime is two time longer than general AGM lead-acid battery. Other advantages are good against thermal lose control, good overcharge protection, good stability and safety. Although it is more expensive than AGM battery, it’s worth it. Thus, the vehicle installed eight 12V/70Wp m-Si panels and six 8V/150Ah gel batteries. In order to support above type of six solar vehicles operation during continuous five overcast and rainy days in economic way, the PV standalone station need 186 PV panels and 127 gel batteries. The total cost is 582700SEK. The solar charge controller of the vehicle is researched and developed by New Energy Source Research Centre of Shenyang Institute of Engineering, who offers all materials for this project. By the experiments its effectiveness of MPPT and low internal losses is proved. Moreover, The PV vehicle with 560Wp m-Si PV array can run 87km, which is 1.5 times distance more than the general electric car with full load when average radiation is 749W/m2.

  • 54.
    Fiedler, Frank
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    A testing and demonstration facility for PV systems and components2013Ingår i: Proceedings of 3rd Symposium Small PV Applications: Rural Electrification and commercial use / [ed] OTTI e.V., Regensburg, Germany, 2013, s. 111-116Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    A test and demonstration facility for PV and PV hybrid systems and system components has been designed and installed at Dalarna University in Sweden. The facility allows studies of complete PV systems or single components in a range of 0.1-10 kW. The facility includes two grid-connected PV systems, a PV Hybrid off-grid system, three emulators and the necessary measurement and control equipment. Tests can be done manually or automatically through programmed test procedures controlled that will be implemented in Labview. The facility shall be used by researchers, professionals of the industry and engineering students.

  • 55.
    Fiedler, Frank
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Förstudie småskalig pelletanvändning i Chile2009Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Syftet med denna förstudie var att undersöka vilka förutsättningar finns för pelletvärmesystem och om marknaden i Chile kan vara intressant för svenska företag som tillverka den typ värmesystem. De viktigaste resultaten är: 1. Träpellets finns tillgängliga i Chile tillverkade av tre företag med en total tillverkningskapacitet av 100000 ton. En typ pellets finns på marknaden som har ungefär samma kvalitet som svensk tillverkade pellets. 2. Än så länge finns i Chile bara ett företag som tillverkar pelletskaminer. Det finns ytterligare företag som importerar pelletskaminer och pelletspannor från Europa. 3. På grund av det milda klimatet har bostadshus inga vattenburna värmedistributionssystem eller även inga värmesystem alls. 4. Mest vanliga är enkla vedkaminer. Det finns potential att ersätta dessa kaminer speciellt i storstadsområdet där deras användning har inskränkts på grund av de höga utsläppen de orsakar och där gas, el eller olja för uppvärmning kan ersättas. 5. Priser för svenska pelletkaminer är för höga för att kunna konkurrera på den chilenska marknaden. 6. På grund av det milda klimatet och de höga kostnaderna för vattenburna värmedistributionssystem kommer vattenburna värmesystem att ha även i framtiden bara en liten marknad.

  • 56.
    Fiedler, Frank
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Persson, Tomas
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Optimisation method for solar heating systems in combination with pellet boilers/stoves2007Ingår i: International Journal of Green Energy, ISSN 1543-5075, E-ISSN 1543-5083, Vol. 4, nr 3, s. 325-337Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study an optimisation method for the design of combined solar and pellet heating systems is presented and evaluated. The paper describes the steps of the method by applying it for an example system. The objective of the optimisation was to find the design parameters that give the lowest auxiliary energy (pellet fuel + auxiliary electricity) and carbon monoxide (CO) emissions for a system with a typical load, a single family house in Sweden. Weighting factors have been used for the auxiliary energy use and CO emissions to give a combined objective function. Different weighting factors were tested. The results show that extreme weighting factors lead to their own minima. However, it was possible to find factors that ensure low values for both auxiliary energy and CO emissions, and suitable weighting factors are suggested.

  • 57.
    Fiedler, Frank
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Vestlund, Johan
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Erfahrungen mit einem neu entwickelten kombinierten Pellet- und Solarheizungssystems2008Ingår i: 18. Symposium Thermische Solarenergi, Kloster Banz, Bad Staffelstein, 2008Konferensbidrag (Övrigt vetenskapligt)
  • 58.
    Fiedler, Frank
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Vestlund, Johan
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Monitoring results of combined pellet and solar heating system2007Ingår i: ISES Solar World Congress 2007, ISES 2007, 2007, Vol. 2, s. 867-871Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    In this study the monitoring results of prototype installation of a recently developed solar combisystem have been evaluated. The system, that uses a water jacketed pellet stove as auxiliary heater, was installed in a single family house in Borlänge/Sweden. In order to allow an evaluation under realistic conditions the system has been monitored for a time period of one year. From the measurements of the system it could be seen that it is important that the pellet stove has a sufficient buffer store volume to minimize cycling. The measurements showed also that the stove gives a lower share of the produced heat to the water loop than measured under stationary conditions. The solar system works as expected and covers the heat demand during the summer and a part of the heat demand during spring and autumn. Potential for optimization exists for the parasitic electricity demand. The system consumes 680 kWh per year for pumps, valves and controllers which is more than 4% of the total primary heating energy demand.

  • 59.
    Fiedler, Frank
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Nielsen, Caroline
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Design Study of a PV-Diesel Hybrid System for a Micro-Grid in Tanzania2012Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    In 2008 a micro PV-Diesel Hybrid system has been installed at the Ihushi Development Center (IDC) near Mwanza in Tanzania. In April 2011 a monitoring system was installed at IDC to study the system performance and the usage of the system. Measured data from April to July 2011 have been used to model the system with the simulation software HOMER. One question was if HOMER allows accurate modelling and simulations of the actual system. In addition, it has been studied if the current system can be optimized and what system design solutions are most promising when the system need to be redesigned for a higher load.

  • 60.
    Fiedler, Frank
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Pazmino, Victor
    Berruezo, Irati
    PV-Wind Hybrid Systems for Swedish Locations2008Ingår i: 4th European PV-Hybrid and Mini-Grid Conference, Glyfada, Greece, 2008Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    PV-Wind-Hybrid systems for stand-alone applications have the potential to be more cost efficient compared to PV-alone systems. The two energy sources can, to some extent, compensate each others minima. The combination of solar and wind should be especially favorable for locations at high latitudes such as Sweden with a very uneven distribution of solar radiation during the year. In this article PV-Wind-Hybrid systems have been studied for 11 locations in Sweden. These systems supply the household electricity for single family houses. The aim was to evaluate the system costs, the cost of energy generated by the PV-Wind-Hybrid systems, the effect of the load size and to what extent the combination of these two energy sources can reduce the costs compared to a PV-alone system. The study has been performed with the simulation tool HOMER developed by the National Renewable Energy Laboratory (NREL) for techno-economical feasibility studies of hybrid systems. The results from HOMER show that the net present costs (NPC) for a hybrid system designed for an annual load of 6000 kWh with a capacity shortage of 10% will vary between $48,000 and $87,000. Sizing the system for a load of 1800 kWh/year will give a NPC of $17,000 for the best and $33,000 for the worst location. PV-Wind-Hybrid systems are for all locations more cost effective compared to PV-alone systems. Using a Hybrid system is reducing the NPC for Borlänge by 36% and for Lund by 64%. The cost per kWh electricity varies between $1.4 for the worst location and $0.9 for the best location if a PV-Wind-Hybrid system is used.

  • 61.
    Fiedler, Frank
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Pazmino, Victor
    Berruezo, Irati
    Techno-economic feasibility analysis of PV-wind hybrid systems for Sweden2008Ingår i: Eurosun 2008, Lisbon, 2008Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    PV-Wind-Hybrid systems for stand-alone applications have the potential to be more cost efficient compared to PV-alone systems. The two energy sources can, to some extent, compensate each others minima. The combination of solar and wind should be especially favorable for locations at high latitudes such as Sweden with a very uneven distribution of solar radiation during the year. In this article PV-Wind-Hybrid systems have been studied for 11 locations in Sweden. These systems supply the household electricity for single family houses. The aim was to evaluate the system costs, the cost of energy generated by the PV-Wind-Hybrid systems, the effect of the load size and to what extent the combination of these two energy sources can reduce the costs compared to a PV-alone system. The study has been performed with the simulation tool HOMER developed by the National Renewable Energy Laboratory (NREL) for techno-economical feasibility studies of hybrid systems. The results from HOMER show that the net present costs (NPC) for a hybrid system designed for an annual load of 6000 kWh with a capacity shortage of 10% will vary between $48,000 and $87,000. Sizing the system for a load of 1800 kWh/year will give a NPC of $17,000 for the best and $33,000 for the worst location. PV-Wind-Hybrid systems are for all locations more cost effective compared to PV-alone systems. Using a Hybrid system is reducing the NPC for Borlänge by 36% and for Lund by 64%. The cost per kWh electricity varies between $1.4 for the worst location and $0.9 for the best location if a PV-Wind-Hybrid system is used.

  • 62.
    Fiedler, Frank
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Persson, Tomas
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Annual CO-emissions of combined pellet and solar heating systems2007Ingår i: ISES Solar World Congress 2007, ISES 2007, 2007, Vol. 4, s. 2468-2472Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Emissions are an important aspect of a pellet heating system. High carbon monoxide emissions are often caused by unnecessary cycling of the burner when the burner is operated below the lowest combustion power. Combining pellet heating systems with a solar heating system can significantly reduce cycling of the pellet heater and avoid the inefficient summer operation of the pellet heater. The aim of this paper was to study CO-emissions of the different types of systems and to compare the yearly CO-emissions obtained from simulations with the yearly CO-emissions calculated based on the values that are obtained by the standard test methods. The results showed that the yearly CO-emissions obtained from the simulations are significant higher than the yearly CO-emissions calculated based on the standard test methods. It is also shown that for the studied systems the average emissions under these realistic annual conditions were greater than the limit values of two Eco-labels. Furthermore it could be seen that is possible to almost halve the CO-emission if the pellet heater is combined with a solar heating system.

  • 63.
    Fiedler, Frank
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Persson, Tomas
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Carbon monoxide emissions of combined pellet and solar heating systems2007Ingår i: International Green Energy Conference III, Västerås, 2007Konferensbidrag (Övrigt vetenskapligt)
  • 64.
    Fiedler, Frank
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Persson, Tomas
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Carbon monoxide emissions of combined pellet and solar heating systems2009Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 86, nr 2, s. 135-143Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Emissions are an important aspect of a pellet heating system. Low harmful emissions, particularly carbon monoxide, are a measure of a well performing system. High carbon monoxide emissions are often caused by unnecessary cycling of the burner and when the average load is below the lowest possible combustion power of the burner. Combining pellet heaters with a solar heating system can significantly reduce cycling of the pellet heater and avoid the inefficient summer operation of the pellet heater. Five combined systems representing the range of typical solutions of this system type and one recently developed system have been studied, modelled and simulated. These systems are compared to a reference system, which is based on a pellet boiler and is not combined with a solar heating system. The aim was to study CO-emissions of the different types of systems and to analyse the potential of CO-emission reduction when the pellet heater is combined with a solar heating systems. Another aim was to compare the yearly CO-emissions obtained from simulations under realistic dynamic conditions with the yearly CO-emissions calculated based on the values that are obtained by the standard test methods. The study was performed with the simulation tool TRNSYS. The parameter used in the study have been identified from lab measurements on existing pellet boilers/stoves and solar heating systems. The results from the simulations show that it is possible to almost halve the CO-emission if the pellet heater is combined with a solar heating system. The results also show that the CO-emission of existing combined solar and pellet heating systems can be drastically reduced if the pellet heater is properly controlled and some basic design rules are observed. This can also be seen when analyzing the results for the new system concept where these rules have been taken into account. Comparing the yearly CO-emissions obtained from the simulations with the yearly CO-emissions calculated based on the standard test methods shows that using the latter give too low CO-values for the whole year. It is also shown that for the existing systems the average emissions under these realistic annual conditions were greater than the limit values of two Eco-labels.

  • 65.
    Fiedler, Frank
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Persson, Tomas
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    CO-Emissionen solarer Kombisysteme mit Holzpelletkesseln2008Ingår i: 18. Symposium Thermische Solarenergie, Kloster Banz, Bad Staffelstein, 2008Konferensbidrag (Övrigt vetenskapligt)
  • 66.
    Fiedler, Frank
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Persson, Tomas
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Reduction of co-emissions by combining pellet and solar heating systems2008Ingår i: Eurosun 2008, Lisbon, 2008Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Emissions are an important aspect of a pellet heating system. High carbon monoxide emissions are often caused by unnecessary cycling of the burner when the burner is operated below the lowest combustion power. Combining pellet heating systems with a solar heating system can significantly reduce cycling of the pellet heater and avoid the inefficient summer operation of the pellet heater. The aim of this paper was to study CO-emissions of the different types of systems and to compare the yearly CO-emissions obtained from simulations with the yearly CO-emissions calculated based on the values that are obtained by the standard test methods. The results showed that the yearly CO-emissions obtained from the simulations are significant higher than the yearly CO-emissions calculated based on the standard test methods. It is also shown that for the studied systems the average emissions under these realistic annual conditions were greater than the limit values of two Eco-labels. Furthermore it could be seen that is possible to almost halve the CO-emission if the pellet heater is combined with a solar heating system.

  • 67. Fiedler, Frank
    et al.
    Persson, Tomas
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Nordlander, Svante
    Heat losses and thermal performance of commercial combined solar and pellet heating systems2004Ingår i: Eurosun 2004, Freiburg/Germany, 2004Konferensbidrag (Övrigt vetenskapligt)
    Abstract [un]

    Various pellet heating systems are marketed in Sweden, some of them in combination with a solar heating system. Several types of pellet heating units are available and can be used for a combined system. This article compares four typical combined solar and pellet heating systems: System 1 and 2 two with a pellet stove, system 3 with a store integrated pellet burner and system 4 with a pellet boiler. The lower efficiency of pellet heaters compared to oil or gas heaters increases the primary energy demand. Consequently heat losses of the various systems have been studied. The systems have been modeled in TRNSYS and simulated with parameters identified from measurements. For almost all systems the flue gas losses are the main heat losses except for system 3 where store heat losses prevail. Relevant are also the heat losses of the burner and the boiler to the ambient. Significant leakage losses are noticed for system 3 and 4. For buildings with an open internal design system 1 is the most efficient solution. Other buildings should preferably apply system 3. The right choice of the system depends also on whether the heater is placed inside or outside of the heated are. A large potential for system optimization exist for all studied systems, which when applied could alter the relative merits of the different system types.

  • 68.
    Fiedler, Frank
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Scherr, Tino
    Evaluation and simulation of a PV-Wind Hybrid System2009Ingår i: Symposium Small PV-Applications, Ulm, 2009Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    This work is evaluating a PV-Wind Hybrid system that has been installed in 2006 on the roof of Dalarna University in Borlänge/Sweden. Complementing the measurements, simulations with HOMER have been performed for the same system type. The measurements results showed that the PV array of the PV-Hybrid system was providing the major part of the energy even it has only the half of the wind turbine’s nominal rated power. However, the energy production of wind turbine especially during December and January allowed providing an almost constant load of 35W throughout the year. The combination of PV and wind increases the reliability of power supply and allows a significant smaller PV array compared to a PV alone system. The simulation results with HOMER showed good accordance with the measured data. The maximal difference was 3%. Furthermore, HOMER proved to be an easy to use and powerful tool for the sizing of this system type for locations where weather data for solar radiations and wind speed are available.

  • 69.
    Fiedler, Frank
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Zapata, Angel
    Evaluation of a micro PV-Wind hybrid system in Nordic climate conditions2010Ingår i: 5th European Conference PV-Hybrid and Mini-Grid, Tarragona/Spain, 2010Konferensbidrag (Refereegranskat)
    Abstract [en]

    A one year data analysis for a micro PV-Wind hybrid system (0.52 kW + 1 kW), installed in Borlänge/Sweden is presented in this paper. The system performance was evaluated according the guidelines of the IEC 61724 standard. The parameters obtained allow a comparison with similar systems. The measurement data are also used to evaluate the sizing and operation of the hybrid system. In addition, the system was modelled in HOMER to study sizing options.

  • 70. Furbo, Simon
    et al.
    Thür, Alexander
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Fiedler, Frank
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Rekstad, John
    Meir, Michaela
    Blumberga, Dagnija
    Rochas, Claudio
    Solar thermal components adapted to common building standards (SCAS)2006Rapport (Övrigt vetenskapligt)
    Abstract [en]

    Pilot versions of a solar heating/natural gas burner system, of a solar heating/pellet burner system and of a façade/roof integrated polymeric collector have been installed in the summer of 2006 in a number of demonstration houses in Denmark, Sweden and Norway. These three new products have been evaluated by means of measurements of the thermal performance and energy savings of the pilot systems in practice and by means of a commercial evaluation. The conclusion of the evaluations is that the products are attractive for the industry partners METRO THERM A/S, Solentek and SOLARNOR. It is expected that the companies will bring the products into the market in 2007. Further, the results of the project have been presented atinternational and national congresses and seminars for the solar heating branch. The congresses and seminars attracted a lot of interested participants. Furthermore, the project results have been published in international congress papers as well as in national journals in the energy field. Consequently, the Nordic solar heating industry will benefit from the project.

  • 71. Furbo, Simon
    et al.
    Thür, Alexander
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Fiedler, Frank
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Rekstad, John
    Meir, Michaela
    Blumberga, Dagnija
    Rochas, Claudio
    Schifter-Holm, Torbjörn
    Lorenz, Klaus
    Competitive Solar Heating Systems for Residential Buildings (REBUS)2006Rapport (Övrigt vetenskapligt)
    Abstract [en]

    Research on solar combisystems for the Nordic and Baltic countries have been carried out. The aim was to develop competitive solar combisystems which are attractive to buyers and to educate experts in the solar heating field. The participants of the projects were the universities: Technical University of Denmark, Dalarna University, University of Oslo, Riga Technical University and Lund Institute of Technology, as well as the companies: Metro Therm A/S (Denmark), Velux A/S (Denmark), Solentek AB (Sweden), SolarNor (Norway) and SIA Grandeg (Latvia). The project included education, research, development and demonstration. The activities started in 2003 and were finished by the end of 2006. A number of Ph.D. studies in Denmark, Sweden and Latvia, and a post-doc. study in Norway were carried out. Close cooperation between the researchers and the industry partners ensured that the results of the projects can be utilized. The industry partners will soon be able to bring the developed systems into the market. In Denmark and Norway the research and development focused on solar heating/natural gas systems, and in Sweden and Latvia the focus was on solar heating/pellet systems. Additionally, Lund Institute of Technology and University of Oslo studied solar collectors of various types being integrated into the building.

  • 72.
    Gasti, Maria
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Techno-economic Appraisal of Concentrating Solar Power Systems (CSP)2013Självständigt arbete på avancerad nivå (magisterexamen), 12 poäng / 18 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The diffusion of Concentrating Solar Power Systems (CSP) systems is currently taking place at a much slower pace than photovoltaic (PV) power systems. This is mainly because of the higher present cost of the solar thermal power plants, but also for the time that is needed in order to build them. Though economic attractiveness of different Concentrating technologies varies, still PV power dominates the market. The price of CSP is expected to drop significantly in the near future and wide spread installation of them will follow. The main aim of this project is the creation of different relevant case studies on solar thermal power generation and a comparison betwwen them. The purpose of this detailed comparison is the techno-economic appraisal of a number of CSP systems and the understanding of their behaviour under various boundary conditions. The CSP technologies which will be examined are the Parabolic Trough, the Molten Salt Power Tower, the Linear Fresnel Mirrors and the Dish Stirling. These systems will be appropriatly sized and simulated. All of the simulations aim in the optimization of the particular system. This includes two main issues. The first is the achievement of the lowest possible levelized cost of electricity and the second is the maximization of the annual energy output (kWh). The project also aims in the specification of these factors which affect more the results and more specifically, in what they contribute to the cost reduction or the power generation. Also, photovoltaic systems will be simulated under same boundary conditions to facolitate a comparison between the PV and the CSP systems. Last but not leats, there will be a determination of the system which performs better in each case study.

  • 73.
    Gaynullin, Bakhram
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Laser-testing rig 2009: Measurement system for evaluation of shape of concentrating reflector for solar collector Absolicon X102009Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    This Thesis project is a part of the research works in Solar industry. ABSOLICON Solar Concentrator AB has been invented and started production of the prospective solar concentrated system Absolicon X10. The aims of this Thesis project are designing, assembling, calibrating and putting in operation the automatic measurement system intended to evaluate the distribution of density of the solar radiation in focal line of the concentrated parabolic reflectors and to measure the radiation from the artificial source of light as calibration testing tool. On the basis of the requirements of the company administration and needs the designing process of the concentrated reflectors the operation conditions for the Sun walker were formulated. At the first step, the complex design of the whole system was made and division on the parts was defined. After the preliminary conducted simulations the function and operation conditions of the all parts were formulated. At the next steps, the detailed design of all the parts was conducted. Most components were ordered from respective companies. Some of the mechanical components were made in the workshop of the company. All parts of the Sun walker were assembled and tested. Software part, which controls the Sun walker work and conducts measurements of the solar irradiation, was created on the LabVIEW basis. To tune and test software part the special simulator was designed and assembled. When all parts were assembled in the complete system, the Sun walker was tested, calibrated and tuned.

  • 74.
    Gaynullin, Bakhram
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    LASER-TESTING RIG: Measurement System for evaluation of Shape of concentrating reflector for solar collector Absolicon X102009Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    This Thesis project is a part of the all-round automation of production of concentrating solar PV/T systems Absolicon X10. ABSOLICON Solar Concentrator AB has been invented and started production of the prospective solar concentrated system Absolicon X10. The aims of this Thesis project are designing, assembling, calibrating and putting in operation the automatic measurement system intended to evaluate the shape of concentrating parabolic reflectors. On the basis of the requirements of the company administration and needs of real production process the operation conditions for the Laser testing rig were formulated. The basic concept to use laser radiation was defined. At the first step, the complex design of the whole system was made and division on the parts was defined. After the preliminary conducted simulations the function and operation conditions of the all parts were formulated. At the next steps, the detailed design of all the parts was conducted. Most components were ordered from respective companies. Some of the mechanical components were made in the workshop of the company. All parts of the Laser-testing rig were assembled and tested. Software part, which controls the Laser-testing rig work, was created on the LabVIEW basis. To tune and test software part the special simulator was designed and assembled. When all parts were assembled in the complete system, the Laser-testing rig was tested, calibrated and tuned. In the workshop of Absolicon AB, the trial measurements were conducted and Laser-testing rig was installed in the production line at the plant in Soleftea.

  • 75.
    Gaynullin, Bakhram
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Universal Experimental Measurement System «Sun-Walker»: Automotive measurement system for the evaluation of the solar irradiation distribution for the tests of the solar concentrated systems.2010Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    This Thesis project is a part of the research conducted in Solar industry. ABSOLICON Solar Concentrator AB has invented and started production of the prospective solar concentrated system Absolicon X10. The aims of this Thesis project are designing, assembling, calibrating and putting in operation the automatic measurement system intended to evaluate distribution of density of solar radiation in the focal line of the concentrated parabolic reflectors and to measure radiation from the artificial source of light being a calibration-testing tool. On the basis of the requirements of the company’s administration and needs of designing the concentrated reflectors the operation conditions for the Sun-Walker were formulated. As the first step, the complex design of the whole system was made and division on the parts was specified. After the preliminary conducted simulation of the functions and operation conditions of the all parts were formulated. As the next steps, the detailed design of all the parts was made. Most components were ordered from respective companies. Some of the mechanical components were made in the workshop of the company. All parts of the Sun-Walker were assembled and tested. The software part, which controls the Sun-Walker work and conducts measurements of solar irradiation, was created on the LabVIEW basis. To tune and test the software part, the special simulator was designed and assembled. When all parts were assembled in the complete system, the Sun-Walker was tested, calibrated and tuned.

  • 76.
    Geisshusler, Simon
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Ray-tracing Simulation of Incident Angle Modifiers (IAM) of Solar Thermal Collectors2006Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    The overall yield factor of solar thermal collectors is strongly affected by the Incident Angle Modifier (IAM). Costly measurement procedures are indispensable and make it often impossible to collect a sufficient number of accurate base points to make sure that the performance of the collector is known under any irradiance condition. Especially asymmetric shapes are subject of investigation, as models of biaxial IAM approximations are much in question. A ray tracing simulation tool based on the commercial software OptiCAD is developed in this work and calculations performed and analyzed. A graphical user interface facilitates modeling of the most common collector types. Emphasis is put on complete collectors rather than simplifications. The resulting IAM graphs are compared with measured data and existing biaxial approximation methods. Former is performed with the help of a diffuse model, which evaluates collector performance under diffuse condition based on the calculated beam IAM values. Moreover, achieved data are implemented in SPF’s software Polysun and yearly solar fractions of a simple district hot water system evaluated. At last, a parametric study discusses the influence of the various material properties on the optical performance of a collector. The results show that an introduction of an accurate universal mathematical description of any IAM seems to be impossible and is affirmed by the comparison of calculated with biaxial approximated values. The great variety of geometric and material properties makes each collector’s curve unique. Further, the traditional IAM definition of flat plate collector may not be applied directly to tube collectors, as it does not consider irradiation entering from the side. Parametric studies show that collector’s inconstant angular absorptance influences overall IAM most, followed by reflector properties if present. In addition, diffuse irradiance at the measuring site causes inaccuracy as well. Most collectors perform better with pure beam irradiance.

  • 77.
    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, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Byggnader står för omkring 40 % av den totala energianvändningen i EU. Energieffektivisering av byggnader är och fortsätter därför att vara en viktig fråga. Även om stora framsteg har gjorts när det gäller att minska energianvändningen i nya byggnader så är det stora beståndet av befintliga byggnader med dålig energiprestanda förmodligen ett ännu viktigare område att fokusera på. Denna avhandling behandlar energieffektiviseringsåtgärder som kan lämpa sig för renovering av befintliga hus, i synnerhet lågtemperaturvärmesystem och ventilationssystem med värmeåtervinning. Energiprestanda, miljöpåverkan och kostnader utvärderas för en rad systemkombinationer, för små och stora hus med olika värmebehov och för olika klimat i Europa. Resultaten togs fram genom simuleringar med energiberäkningsprogram.

    Lågtemperatursystem och värmeåtervinning framstod båda som lovande lösningar för energieffektivisering av europeiska hus, särskilt i norra Europa, eftersom dessa åtgärder har större effekt i kalla klimat och på hus med stort värmebehov. Prestandan för värmepumpar, såväl av utelufts- som frånluftstyp, förbättrades med lågtemperaturvärmesystem. Valet mellan frånluftsvärmepump och värmeåtervinning till ventilationsluft kan antas bero på specifika förhållanden för varje fall, men de är båda mer kostnadseffektiva och har lägre miljöpåverkan än system utan värmeåtervinning. Värmepumpen har fördelen att den kan återvinna värme året runt, förutsatt att den producerar varmvatten.

    Ekonomiska och miljömässiga aspekter av energieffektiviseringsåtgärder stämmer inte alltid överens. Dels lägre kostnad ibland betyda större miljöpåverkan, dels kan det finnas divergens mellan olika miljöaspekter. Detta gör det svårt att fastställa subventioner för att främja energieffektiviseringsåtgärder.

  • 78.
    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 options2014Konferensbidrag (Refereegranskat)
    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.

  • 79.
    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 simulation2014Ingår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 82, s. 512-519Artikel i tidskrift (Refereegranskat)
    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.

  • 80.
    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 study2013Konferensbidrag (Refereegranskat)
    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.

  • 81.
    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) (Övrigt vetenskapligt)
    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.

  • 82.
    Gyulai, Gergö
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    More efficient PV panels by cooling and the Performance enhancement of a PV-driven boat by active cooling2008Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    A competition named Frisian Solar Challenge is organized for solar boats every second year in Holland. A team from the European Solar Engineering School (ESES) at Högskolan Dalarna was participated twice in the race. In this thesis a theoretical design of a cooling system for a PV driven boat is presented and the benefit of that is investigated. The aim is to enhance the output power of the PV panels by way of reducing the cell temperature of the modules. If the panel can deliver more power for the electro-motor during the stages, the boat can go at a higher speed. The method of the design bases on combining the PV with Thermal collector (PVT). The idea is that an absorber plate with rectangular duct-like fluid channels contacting the entire surface is integrated in each of the PV modules by way of mounting with glue on the back sheet. Then all of the modules are interconnected in parallel according to the Tichelmann method. The system is filled with water, which is taken from the lake and forced by pump. In course of the calculation the volume of heat transferred from the PV to the fluid at a maximum fluid flow rate of 700l/hr based on the pump power was estimated first. For determining the transferred heat the fraction of solar radiation dissipated was necessary to define. The formula, which was derived by Matthias Rommel and Wolfgang Moock for the collector efficiency factor F’ of narrow-duct absorbers, was used for determining the transferred heat. After making a diagram containing the calculated values for PV module efficiency plotted against irradiance data from Amsterdam, a difference of 0.8% in efficiency at the highest solar radiation was obtained as a result of cooling. This means that under favourable conditions (I = 860W/m2; Ta = 17.5°C) almost 6% more power can be extracted by decreasing the cell temperature with 20 degrees. Then the overall pressure drop in the system was calculated for selecting the pump. The characteristic curve giving the relationship between the electro-motor performance and the boat speed in case of having a cooling system was made for investigating the benefit of the cooling system. The curve bases on measured data. For estimating the benefit of the cooling system the parameters of the last race such as the distance of the stages were taken as reference. Calculations show that the boat could go at a speed of 1km/h higher on average and the time benefit would be maximum 24 minutes (depending on the distance of the stage) on days with an irradiance of H (500-700) W/m2. On days with an irradiance of H (750-850) W/m2 the average top speed would be 2km/h higher and it would result in a racing time of 37 minutes shorter on average.

  • 83.
    Haberl, Robert
    et al.
    Institute for Solar Technology SPF, HSR University of Applied Sciences, Switzerland.
    Haller, Michell Y.
    Institute for Solar Technology SPF, HSR University of Applied Sciences, Switzerland.
    Papillon, Philippe
    CEA INES, France.
    Chèze,, David
    CEA INES, France.
    Persson, Tomas
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Testing of combined heating systems for small houses: Improved procedures for whole system test methods: Deliverable 2.32015Rapport (Övrigt vetenskapligt)
    Abstract [en]

    Dynamic system test methods for heating systems were developed and applied by the institutes SERC and SP from Sweden, INES from France and SPF from Switzerland already before the MacSheep project started. These test methods followed the same principle: a complete heating system – including heat generators, storage, control etc., is installed on the test rig; the test rig software and hardware simulates and emulates the heat load for space heating and domestic hot water of a single family house, while the unit under test has to act autonomously to cover the heat demand during a representative test cycle. Within the work package 2 of the MacSheep project these similar – but different – test methods were harmonized and improved. The work undertaken includes: 

    • Harmonization of the physical boundaries of the unit under test.

    • Harmonization of the boundary conditions of climate and load.

    • Definition of an approach to reach identical space heat load in combination with an autonomous control of the space heat distribution by the unit under test.

    • Derivation and validation of new six day and a twelve day test profiles for direct extrapolation of test results.

     

    The new harmonized test method combines the advantages of the different methods that existed before the MacSheep project. The new method is a benchmark test, which means that the load for space heating and domestic hot water preparation will be identical for all tested systems, and that the result is representative for the performance of the system over a whole year. Thus, no modelling and simulation of the tested system is needed in order to obtain the benchmark results for a yearly cycle. The method is thus also applicable to products for which simulation models are not available yet.

    Some of the advantages of the new whole system test method and performance rating compared to the testing and energy rating of single components are: 

    • Interaction between the different components of a heating system, e.g. storage, solar collector circuit, heat pump, control, etc. are included and evaluated in this test.

    • Dynamic effects are included and influence the result just as they influence the annual performance in the field.

    • Heat losses are influencing the results in a more realistic way, since they are evaluated under "real installed" and representative part-load conditions rather than under single component steady state conditions.

     

    The described method is also suited for the development process of new systems, where it replaces time-consuming and costly field testing with the advantage of a higher accuracy of the measured data (compared to the typically used measurement equipment in field tests) and identical, thus comparable boundary conditions. Thus, the method can be used for system optimization in the test bench under realistic operative conditions, i.e. under relevant operating environment in the lab.

     

    This report describes the physical boundaries of the tested systems, as well as the test procedures and the requirements for both the unit under test and the test facility. The new six day and twelve day test profiles are also described as are the validation results.

  • 84.
    Haddi, Jihad
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Thermal Evaluation of a Solarus PV-T collector2013Självständigt arbete på avancerad nivå (magisterexamen), 12 poäng / 18 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Low concentrator PV-T hybrid systems produce both electricity and thermal energy; this fact increases the overall efficiency of the system and reduces the cost of solar electricity. These systems use concentrators which are optical devices that concentrate sunlight on to solar cells and reduce expensive solar cell area. This thesis work deals with the thermal evaluation of a PV-T collector from Solarus.Firstly the thermal efficiency of the low concentrator collector was characterized for the thermal-collector without PV cells on the absorber. Only two types of paint were on the absorber, one for each trough of the collector. Both paints are black one is glossy and the other is dull,. The thermal efficiency at no temperature difference between collector and ambient for these two types of paint was 0.65 and 0.64 respectively; the U-value was 8.4 W/m2°C for the trough with the glossy type of paint and 8.6 W/m2°C for the trough with dull type of paint. The annual thermal output of these two paints was calculated for two different geographic locations, Casablanca, Morocco and Älvkarleby, Sweden.Secondly the thermal efficiency was defined for the PV-T collector with PV cells on the absorber. The PV cells cover 85% of the absorber, without any paint on the rest of the absorber area. We also tested how the electrical power output influences the thermal power output of the PV-T collector. The thermal and total performances for the PV-T collector were only characterized with reflector sides, because of the lack of time we could not characterize them with transparent sides also.

  • 85. 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 Development2011Ingår i: Journal of Building Performance Simulation, Taylor & Francis, ISSN 1940-1493, E-ISSN 1940-1507, Vol. 4, nr 1, s. 1-18Artikel i tidskrift (Refereegranskat)
    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.

  • 86. 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 Measurements2011Ingår i: Journal of Building Performance Simulation, Taylor & Francis, ISSN 1940-1493, E-ISSN 1940-1507, Vol. 4, nr 1, s. 19-36Artikel i tidskrift (Refereegranskat)
    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.

  • 87. 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 losses2010Ingår i: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 84, nr 6, s. 997-1007Artikel i tidskrift (Refereegranskat)
    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.

  • 88. Haller, Michel
    et al.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Streicher, Wolfgang
    Combined Solar and Pellet Heating Systems for Houses: Improvement of Energy Efficiency and Reduction of Boiler ON/OFF cycling2010Ingår i: Eurosun 2010, Graz, Austria, 2010Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Annual simulations of combined solar and pellet combisystems have been performed based on measurements of two pellet boilers and a burner integrated into a solar thermal energy storage (TES). The results show that the investigated burner integration is more energy efficient in comparison with the external pellet boiler solution. The flue gas losses were the predominant losses measured for steady state burner operation, but heat losses to the ambient were predominant in the annual simulation results. The number of ON/OFF cycles of the pellet burner depends to a high degree on the control strategy implemented to adapt the power modulation to the current demand, and varied from almost 3000/a in the worst case to less than 900/a in the best case simulated. Based on parametric simulation studies, it was determined that the fractional energy savings of both systems could be increased fromaround 20% to 30% for a house with 4.6 kW heat load at climate Zurich without increasing the area of 10 m2 flat plate collectors or the TES volume of 850 litres. A comparison with a hypothetical TES of the tank-in-tank design showed additional potential for improvement due to a smaller area of the TES that has to be kept at high temperatures for DHW use.

  • 89.
    Haller, Michel Yves
    et al.
    SPF Institut für Solartechnik, Hochschule für Technik.
    Haberl, Robert
    SPF Institut für Solartechnik, Hochschule für Technik.
    Persson, Tomas
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Kovacs, Peter
    Technical Research Institutue of Sweden.
    Chèze, David
    CEA, INES.
    Papillon, Philippe
    CEA, INES.
    Dynamic whole system testing of combined renewable heating systems: the current state of the art2013Ingår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 66, s. 667-677Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Objective: For the evaluation of the energetic performance of combined renewable heating systems that supply space heat and domestic hot water for single family houses, dynamic behaviour, component interactions, and control of the system play a crucial role and should be included in test methods.

    Methods: New dynamic whole system test methods were developed based on “hardware in the loop” concepts. Three similar approaches are described and their differences are discussed. The methods were applied for testing solar thermal systems in combination with fossil fuel boilers (heating oil and natural gas), biomass boilers, and/or heat pumps.

    Results: All three methods were able to show the performance of combined heating systems under transient operating conditions. The methods often detected unexpected behaviour of the tested system that cannot be detected based on steady state performance tests that are usually applied to single components.

    Conclusion: Further work will be needed to harmonize the different test methods in order to reach comparable results between the different laboratories.

    Practice implications: A harmonized approach for whole system tests may lead to new test standards and improve the accuracy of performance prediction as well as reduce the need for field tests.

  • 90.
    Haynes, Terrence
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Design and assessment of a large commercial Photovoltaic System in Barbados2013Självständigt arbete på avancerad nivå (magisterexamen), 12 poäng / 18 hpStudentuppsats (Examensarbete)
    Abstract [en]

    One of the main aims of this thesis is to design an optimized commercial Photovoltaic (PV) system in Barbados from several variables such as racking type, module type and inverter type based on practicality, technical performance as well as financial returns to the client. Detailed simulations are done in PVSYST and financial models are used to compare different systems and their viability. Once the preeminent system is determined from a financial and performance perspective a detailed design is done using PVSYST and AutoCAD to design the most optimal PV system for the customer. In doing so, suitable engineering drawings are generated which are detailed enough for construction of the system. Detailed cost with quotes from relevant manufacturers, suppliers and estimators become instrumental in determining Balance of System Costs in addition to total project cost. The final simulated system is suggested with a PV capacity of 425kW and an inverter output of 300kW resulting in an array oversizing of 1.42. The PV system has a weighted Performance Ratio of 77 %, a specific yield of 1467 kWh/kWp and a projected annual production of 624 MWh/yr. This system is estimated to offset approximately 28 % of Carlton’s electrical load annually. Over the course of 20 years the PV system is projected to produce electricity at a cost of $0.201USD/kWh which is significantly lower than the $0.35 USD/kWh paid to the utility at the time of writing this thesis. Due to the high cost of electricity on the island, an attractive Feed-In-Tariff is not necessary to warrant the installation of a commercial System which over a lifetime which produces electricity at less than 60% of the cost to the user purchasing electricity from the utility. A simple payback period of 5.4 years, a return on investment of 17 % without incentives, in addition to an estimated diversion of 6840 barrels of oil or 2168 tonnes of CO2 further provides compelling justification for the installation of a commercial Photovoltaic System not only on Carlton A-1 Supermarket, but also island wide as well as regionally where most electricity supplies are from imported fossil fuels.

  • 91.
    Hedlund, Gun
    et al.
    Örebro universitet.
    Perman, Karin
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Energieffektiva bostäder - ett ouppnåeligt politiskt mål?: Kommunikation och styrmedel i Jakobsgårdarna2013Rapport (Övrigt vetenskapligt)
  • 92.
    Hedlund, Gun
    et al.
    Örebro universitet.
    Perman, Karin
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    “In this area we have it so nice”2013Ingår i: 3rd European Conference on Politics and Gender (ECPG) : Papers, 2013Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Segregation and poverty in multi-family housing areas is a challenge facing many European cities creating a new policies for the post-welfare states. Due to privatization, retrenchment of the welfare state and increased immigration Sweden is not exception. City politics with different large scale projects to prevent further stigmatization and bad reputation of a specific housing area has during the last 10-15 years become a national and local policy in Swedish cities and municipalities. Ideas of deliberation and inclusion is common in the govenance of these projects. Immigrant women are mostly described as a target group as they are considered being passive, isolated and lacking the skills and knowledge to behave as the responsible, acitve citizen and consumer of good and sustainable housing. In this paper we present data from a case-study of a Swedish local housing policy being a part of multi-level governace regarding energy efficiancy and refurbishment of public housing. 40 per cent of the families have a background in Asia/Africa. Gender and etnicity play a crucial role when Swedish women in the name of care in socal projects face the immigrant women.

  • 93.
    Hedlund, Gun
    et al.
    Örebro universitet.
    Perman, Karin
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    The heating, especially warm water, is exceptionally high in this area…”2012Konferensbidrag (Refereegranskat)
  • 94.
    Heier, Johan
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Energieffektivisering i småhus i Dalarna2013Rapport (Övrigt vetenskapligt)
    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.

  • 95.
    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 energilagring2013Ingår i: Energi & miljö, ISSN 1101-0568, nr 10, s. 63-66Artikel i tidskrift (Övrig (populärvetenskap, 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.

  • 96.
    Heier, Johan
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik. KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Energy Efficiency through Thermal Energy Storage: Possibilities for the Swedish Building Stock2013Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Behovet av värme och kyla i byggnader utgör en betydande del av ett lands totala energianvändning och att reducera detta behov är av yttersta vikt för att nå nationella samt internationella mål för minskad energianvändning och minskade utsläpp. En viktig väg för att nå dessa mål är att öka andelen förnyelsebar energi för kylning och uppvärmning av byggnader. Det kanske största hindret med detta är det faktum att det ofta råder obalans mellan tillgången på förnyelsebar energi och behovet av värme och kyla, vilket gör att denna energi inte kan utnyttjas direkt. Detta är ett av problemen som kan lösas genom att använda termisk energilagring (TES) för att lagra värme eller kyla från när det finns tillgängligt till dess att det behövs.

    Denna avhandling fokuserar på kombinationen av TES och byggnader för att nå högre energieffektivitet för uppvärmning och kylning. Olika tekniker för energilagring, samt även kombinationen av TES och byggnader, har undersökts och sammanfattats genom en omfattande litteraturstudie. För att kunna identifiera byggnadstyper vanliga i Sverige gjordes även en kartläggning av det svenska byggnadsbeståndet. Inom ramen för denna avhandling resulterade kartläggningen i valet av tre typbyggnader, två småhus samt en kontorsbyggnad, utav vilka de två småhusen användes i en simuleringsfallstudie av passiv TES genom ökad termisk massa (både sensibel och latent). Den andra fallstudien som presenteras i denna avhandling är en utvärdering av ett existerande borrhålslager för säsongslagring av solvärme i ett bostadsområde. I detta fall användes verkliga mätdata i utvärderingen samt i jämförelser med tidigare utvärderingar.

    Litteraturstudien visade att användningen av TES öppnar upp möjligheter för minskat energibehov och minskade topplaster för värme och kyla samt även möjligheter till en ökad andel förnyelsebar energi för att täcka energibehovet. Genom att använda passiv lagring genom ökad termisk massa i byggnaden är det även möjligt att minska variationer i inomhustemperaturen och speciellt minska övertemperaturer under varma perioder; något som kan leda till att byggnader som normalt behöver aktiv kylning kan klara sig utan sådan. Analysen av kombinationen av TES och byggnadstyper bekräftade att TES har en betydande potential för ökad energieffektivitet i byggnader, men belyste även det faktum att det fortfarande krävs mycket forskning innan vissa av lagringsteknikerna kan bli kommersiellt tillgängliga. I simuleringsfallstudien drogs slutsatsen att en ökad termisk massa endast kan bidra till en liten minskning i värmebehovet, men att tiden med inomhustemperaturer över 24 °C kan minskas med upp till 20 %. Fallstudien av borrhålslagret visade att även om själva lagringssystemet fungerade som planerat så ledde värmeförluster i resten av systemet, samt vissa problem med driften av systemet, till en lägre solfraktion än beräknat.

    Arbetet inom denna avhandling har visat att TES redan används med framgång i många byggnadsapplikationer (t.ex. varmvattenberedare eller ackumulatortankar för lagring av solvärme) men att det fortfarande finns en stor potential i en utökad användning av TES. Det finns dock hinder såsom behovet av mer forskning för både vissa lagringstekniker samt lagringsmaterial, i synnerhet för lagring med fasändringsmaterial och termokemisk lagring.

  • 97.
    Heier, Johan
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Intervjustudie och simulering som metoder för att undersöka termiska energilager i byggnader2011Ingår i: Metoder för tvärvetenskaplig analys av energisystem - några exempel / [ed] Karlsson, Magnus; Palm, Jenny, Linköping: Program Energisystem , 2011, s. 73-82Kapitel i bok, del av antologi (Övrigt vetenskapligt)
    Abstract [sv]

    Termiska energilager i byggnader kan ha många fördelar och i denna essä utreds möjligheterna till att använda byggnadssimulering samt intervjuer för att visa på dess potential. Byggnadssimulering kan hjälpa till i bedömningen av hur stor potential till energieffektivisering som finns för olika kombinationer av lagringsteknik och byggnadstyp. Intervjuer kan bland annat ge svar på frågeställningar som hur stora variationer i inomhusklimat som är accepterade av boende i/användare av byggnader eller vilka lagringstekniker, om några, som övervägs vid nybyggnation eller renovering. Även en kombination av de två metoderna kan bidra med positiva synergieffekter. Till exempel är det möjligt att intervjuer med teknisk personal i befintliga byggnader med termisk energilagring kan leda till förbättringar i simuleringsmodeller då styrning av lagret kan förstås på ett bättre vis. Vid intervjuer kan resultat från simuleringar jämföras med hur energilagringssystemen fungerar i verkligheten; finns det skillnader eller problem som gör att lagren i praktiken fungerar på andra sätt än vad som visas i simuleringarna?

  • 98.
    Heier, Johan
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Paketering av energisparåtgärder i småhus2013Rapport (Övrigt vetenskapligt)
    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.

  • 99.
    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
    Department of Energy Technology, KTH.
    Combining Thermal Energy Storage with Buildings: A Review2015Ingår i: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 42, s. 1305-1325Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Thermal Energy Storage (TES) has been a topic of research for quite some time and has proven to be a technology that can have positive effects on the energy efficiency of a building by contributing to an increased share of renewable energy and/or reduction in energy demand or peak loads for both heating and cooling. There are many TES technologies available, both commercial and emerging, and the amount of published literature on the subject is considerable. Literature discussing the combination of thermal energy storage with buildings is however lacking and it is therefore not an easy task to decide which type of TES to use in a certain building. The goal of this paper is to give a comprehensive review of a wide variety of TES technologies, with a clear focus on the combination of storage technology and building type. The results show many promising TES technologies, both for residential and commercial buildings, but also that much research still is required, especially in the fields of phase change materials and thermochemical storage.

  • 100.
    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 12010Ingår i: Clima2010, Antalya, Turkiet, 2010Konferensbidrag (Övrigt vetenskapligt)
    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.

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