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  • 151.
    Lorenz, Klaus
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Persson, Tomas
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Evaluation of Solar Thermal Combisystems for the Swedish Climate2000In: Eurosun 2000, Copenhagen, 2000Conference paper (Other academic)
    Abstract [en]

    This paper summarises the results of previous work in the area and then goes on to describe the results of a more detailed simulation study of a number of different system designs. For these systems, the boundary conditions were: modern Swedish single family house in Stockholm (255 MJ/m2.year heating load); moderate DHW load (11.3 GJ/year); and typical Swedish single glazed collector with selective surface absorber. For the majority of the parametric studies, these boundary conditions were kept constant, but a section of the paper describes the influence of these boundary conditions on the system performance. All system designs and their variations are compared to a reference solar combisystem, the most common combisystem type in Sweden. The simulation work is based on models that have been validated against detailed measurements on several stores and components. The results show that the fractional energy savings can be increased by over 30% from the reference combisystem, given the same system size, collector type and load size. The two major improvements in performance are achieved by using an external DHW unit instead of the two heat exchangers in the store, and by having a low return temperature from the heating circuit. Several other variations are shown to have lesser influence on the energy savings.

  • 152.
    Lorenz, Klaus
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Persson, Tomas
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Tepe, Rainer
    Variation of System Performance with Design and Climate for Combisystems in Sweden1998In: Eurosun -98, Portoroz, Slovenia, 1998Conference paper (Other academic)
    Abstract [en]

    In Sweden, 90% of the solar heating systems are solar domestic hot water and heating systems (SDHW&H), so called combisystems. These generally supply most of the domestic hot water needs during the summer and have enough capacity to supply some energy to the heating system during spring and autumn. This paper describes a standard Swedish combisystem and how the output from it varies with heating load, climate within Sweden, and how it can be increased with improved system design. A base case is defined using the standard combi- system, a modern Swedish single family house and the climate of Stockholm. Using the simulation program Trnsys, parametric studies have been performed on the base case and improved system designs. The solar fraction could be increased from 17.1% for the base case to 22.6% for the best system design, given the same system size, collector type and load. A short analysis of the costs of changed system design is given, showing that payback times for additional investment are from 5-8 years. Measurements on system components in the laboratory have been used to verify the simulation models used. More work is being carried out in order to find even better system designs, and further improvements in system performance are expected.

  • 153.
    Lorenz, Klaus
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Broman, Lars
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Systematisk undersökning av villasystem för solvärme: delrapport från ett pågående projekt1991Report (Other academic)
  • 154.
    Lorenz, Klaus
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Henning, Annette
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Välja värmesystem för villan: Enkla tips som sparar miljön och ger valfrihet inför framtida förändringar2005Book (Other academic)
    Abstract [sv]

    "Välja värmesystem för villan" är en populärt skriven tvärvetenskaplig skrift. Villahushåll som planerar att förändra sitt värmesystem får konkreta tips och råd som utgår från deras egen situation. De får rådet att tänka långsiktigt och undvika fallgropar som gör värmesystemet svårt att förändra. Skriften är den första delen i en serie om flexibla värmesystem. Den andra delen vänder sig till installatörer.

  • 155.
    Lorenz, Klaus
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Persson, Tomas
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Comparison of External DHW Load Side Heat Exchange Units for Small Solar Storage Systems1997In: North Sun ´97 / [ed] Konttinen, P.; Lund, P. D., Espoo-Otaniemi, Finland, 1997Conference paper (Other academic)
    Abstract [en]

    This paper compares the performance of four load side heat exchange units that could be used with storage tanks in solar heating systems to make domestic hot water (DHW). The unit consists of a flat plate heat exchanger and a controller that regulates the primary (tank side) flow in a predetermined way. Several tests were carried out in order to determine the static and dynamic performance of the units. The two best units were connected in turn to a standard solar heating system and the thermal performance of the whole system was measured using a six-day test sequence. In addition simulation models of these two units were constructed and their parameters identified. The results show that not all of the units are suitable for use in solar heating systems. Two completely different control strategies achieve reasonable thermal performance. When used in a standard high flow Swedish solar system instead of the usual internal load side heat exchangers, the solar fraction of the whole system is improved by over 10%.

  • 156.
    Lorenz, Klaus
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Tepe, Rainer
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Persson, Tomas
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Förstude: Beskrivning av uppvärmningssystem med solfångare och värmepump för området Anneberg i Danderyds Kommun1999Report (Other academic)
    Abstract [sv]

    Anneberg är ett område i Danderyds kommun där det skall beredas plats för ett nytt bostadsområde. Området skall bebyggas med flerbostadshus, gruppbostäder och ett sjukhem. Denna förstudie beskriver översiktligt 3 systemförslag som kan användas för uppvärmning av husen i bostadsområdet Anneberg. Målsättningen är att presentera uppvärmningssystem som visar hur solenergi kan användas för att öka värmepumpsystemens värmefaktor. Systemen modellerades i TRNSYS och systemfunktionen samt energiflöden simulerades. Simulerade prestanda för tre olika typer av uppvärmningssystem redovisas. System A är ett vanligt värmepumpsystem med borrhål och värmepump placerad i ett flerfamiljshus av typ 3. System B liknar system A, men har kompletterats med en glasad solfångare för varmvattenberedning. System C är en lösning som kan tillämpas för större byggnader eller för ett område med flera byggnader. Systemet har ett gemensamt värmelager och ett kulvertsystem som förbinder byggnaderna med värmelagret. I varje ansluten byggnad installeras sedan en värmepump och en oglasad solfångare. Simuleringsresultatet redovisas som en värmefaktor för systemets fem första driftår. System A får en värmefaktor på mellan 2,3 och 2,7 för de första 5 driftåren. System B får en värmefaktor på mellan 3,4 och 3,7 och system C får en värmefaktor på mellan 4,0 och 4,5. Studien visar att det går att öka värmefaktorn på en värmepumpanläggning från ca 2,5 upp till 4 eller 4,5 genom att komplettera anläggningen med solfångare och värmelager. Detta innebär att elförbrukningen minskar från att vara ca 40 % av värmebehovet ned till under 25 % av värmebehovet. Det bör således finnas en potential för att komplettera värmepumpanläggningar med solvärme. Vilket utförande som kan bli ekonomiskt intressant kan inte bedömas i denna förstudie. I förstudien visas enbart resultatet för tre enstaka systemutföranden. Inga parametervariationer (tex solfångaryta, antal borrhål och avstånd mellan borrhålen) är utförda. En sådan systemoptimering bör göras med förstudien som utgångsläge.

  • 157.
    Lundvik, Kerstin
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    A Research of Alternative Energy Sources for the Tourist Resort Idre Fjäll2006Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    Presently, Idre Fjäll, a tourist resort located in the Swedish mountains have its cabins heated with electrical power. The environmental department of the municipality of Älvdalen asked me to seek out environmentally friendly alternatives to grid electricity. The objective is to find compatible and suitable solutions for cabins that are not used continually. The solutions mustn’t require effort from the customers and must provide the same or better comfort as did the former system. A mainly theoretical study was carried out. In a first step information was gathered from different sources, then the work of choosing valid alternatives and describing them begun. For some of the calculations, advice from an energy consultant was obtained. Also, a deeper understanding of the technologies described was sought. Different solutions were studied, solar energy (electricity and heat), biogas, pellets and wind power and then each resource was broadly explained, from the technical aspects to its situation nowadays in Sweden. The reason why the solutions must include the usage of renewable resources, is mainly because of the strong interest of the municipalities to get closer to achieving the national environmental objectives Sweden has set. For Idre Fjäll, different systems can be chosen and combined in order to make the utilization of the renewable fuels sustainable. The technology for solar collectors, pellets, biogas and windpower is sufficiently developed to make them interesting alternatives as substitutes to a good part of the grid electricity. Wind power turned out to be one of the best options, the wind status near the resort is very favorable. The financial evaluation shows promise. However, a deep study about the consequences of installing a wind turbine must be made before considering a project of such magnitude.

  • 158.
    Madani, Hatef
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Design of a Solar Desiccant Cooling System2006Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    The division of Building Services Engineering at Chalmers University of Technology, Göteborg, has an air handling unit comprising a desiccant cooling system with an electric heater and intends to install the system in its laboratory. The aims of this project are making a comprehensive proposal including how to design the system in order to use solar energy for regeneration of the desiccant wheel (design of a solar desiccant cooling system), where to install the system in the laboratory, how to use it in order to cool the whole or some parts of the laboratory, how to use it in order to do experiments and how to establish a lab for undergraduate students in order to show them the performance of the system. Firstly, the building where the solar desiccant cooling system is supposed to be installed was described and drawn. In order to find it is better to use the existing desiccant cooling system to cool whole laboratory or some parts of it, the cooling load for the whole laboratory and offices were estimated separately. So, it was known that the cooling load of offices more suits to the cooling capacity of the existing desiccant system. Secondly, the most appropriate types of the solar collectors for the project were determined. Liquid-based and air-based glazed flat-plate and also evacuated-tube solar collector were selected as the proper alternatives. After general description of those types and making comparison among them, liquid-based flat-plate solar collector was selected as the most proper type because of being more common and available than others. So the detailed design was carried out based on this type of collector. The detailed design section is divided to two main parts. In the first part of detailed design, system with liquid-based flat-plate solar collector is analyzed and designed comprehensively. Closed loop at low pressure filled with a glycol mixture-partial evaporation was selected as the collector circuit in the designed solar system. The solar system was designed in order to heat the regeneration air of desiccant wheel from 35°C to 55°C. Two individual control units were presented in order to control both solar and desiccant cooling system operation. The proper place for installation of system in the laboratory was also found and showed in Autocad format. Then the components of the solar system were sized and selected from catalogues. In the second part of the detailed design, system with air-based flat-plate solar collectors was analyzed briefly. Finally, a lab guide for undergraduate students was made in order to make them familiar with the principles of the system and show them what the important parameters and figures of merit are due to the components of the system and how to achieve those parameters basically.

  • 159.
    Maluf, Alexandre Prata
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Solar Heating for Low Income Family Houses in Brazil2006Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    The main objective of this work is to evaluate the potential use of solar heating for domestic use in Brazil, its current situation and possible measures to develop its use, especially for low-income family houses, a still little explored share of the market. The study case aims to evaluate solar heating systems in social interest housing project “Sapucaias”, five years after its implementation. The data analysis shows clearly the success of such technology in providing energy savings allied to social benefits, although some aspects may be improved in future projects, specially to avoid to users from selling the systems, sometimes soon after they receive them, before the benefits are perceived. The use of domestic water solar heating systems is also positive for the overall country electricity grid, in terms of savings of total electricity demand and shift of power during peak hours. Also important are the social benefits born from the use of this technology, namely the economical savings for poor families allied to a higher comfort level achieved: the resulting savings from lower electricity bills are converted in better food and also the purchasing of new domestic appliances. Another evaluation point is related to the possible increase in water consumption as a result of the use of solar heating.

  • 160.
    Marks, Jörgen
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Mattsson, Jan Erik
    Nordlander, Svante
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Malning av pellets och dosering av pulver till pulverbrännare2000Report (Other academic)
  • 161.
    Martin, Seth
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Characterization of Ait Flow and Determination of Working Points in Polymeric Twinwall Solar Air Heater System2006Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    American Solar, Inc. has developed an effective, low-cost solar air heating system based on mass-produced components that are readily available within the United States of America. The system collector and plenum is made of polymeric twinwall sheeting; the system fittings and corrugated duct are plastic. Sealing of the air heater system is achieved with silicone and various fasteners. Air movement is achieved by an assortment of inline, axial blowers. The collectors are modular and can be combined in parallel for multiple configurations. Since the air flow for the collector, fittings and duct had not been characterised, system specification had been inexact. This thesis explains how air flow characterization of the system was achieved. First, axial blowers and single and multi-collector system configurations were specified based on estimated volumetric flow requirements. Second, the various configurations were tested while attached to the specified blowers, and the associated performance data was recorded using an iris damper attached to a differential pressure sensor and a data logger. Third, the resulting performance data was analyzed graphically to determine the characteristic curves of individual components and configurations. Fourth, experimental conclusions were compared to theoretical predictions and available data for similar products to check for consistency. Finally, a design database of configurations with defined working points was created. Background, method, results, and analyses are presented.

  • 162. Mattsson, Cecilia
    et al.
    Berg, Per E O
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Optiplock: manual för plockanalys1999Report (Other academic)
  • 163.
    Mattsson Petersen, Cecilia
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Conditions and constraints for waste management: collection, characterisation and producer responsibility in Sweden2004Doctoral thesis, monograph (Other academic)
  • 164.
    Mattsson Petersen, Cecilia
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Berg, Per E O
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    A Comparison Between Systems for Source Separation of Organic Household Waste2004In: Proceedings of th R'2000 Congress Toront, Canada. June 2000, p. 986-991Article in journal (Other academic)
  • 165.
    Mattsson Petersen, Cecilia
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Berg, Per E O
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Collection of Household Waste: collection within municipal responsibility2002In: Proceedings of the 6th World Congress on Integrated Resources Management/R'02 Geneva SwizerlandArticle in journal (Other academic)
  • 166.
    Mattsson Petersen, Cecilia
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Berg, Per E O
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Collection of Household Waste, Sweden 2000: Collection of Recyclables2001In: Proceedings of the Seventh International Conference on Solid Waste Technology and Management. Philadelphia USA October 2001, p. 484-495Article in journal (Refereed)
  • 167.
    Mattsson Petersen, Cecilia
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Berg, Per E O
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Hushållsavfall i Borlänge kommun: analyser av material en och flerfamiljshus2000Report (Other academic)
    Abstract [sv]

    In Borlänge, source separation has been the basis for management of household waste for over five years. This report reviews today?s system and gives a model for further follow-up through waste grouping. In the basic system waste is separated into three fractions: biodegradable, waste to energy and waste to landfill. All waste is packed in plastic bags, put in separate containers for each fraction, and collected from the property. Separate analyses were made of waste from single family houses and apartment buildings. The amount of waste per household and week, number of non-sorted bags, purity, recovery rate and density of each fraction was calculated. The amount of packaging collected together with the household waste is given. Material collected under the Swedish law of Producers? Responsibility is not covered in this report.

  • 168.
    Mattsson Petersen, Cecilia
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Berg, Per E O
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Hushållsavfall i Falu kommun - Analyser av material en och flerfamiljshus2000Report (Other academic)
    Abstract [sv]

    Det är nästan fem år sedan Falun införde ett system för källsortering av hushållsavfall som omfattar hela kommunen. Idag finns ett behov av uppföljning och kartläggning av dagsläget: Hur fungerar sorteringen vad det gäller deltagande, renhet och kvalitet på utsorterade fraktioner samt återvinningsgrad. Inom ramen för denna studie har vi tagit fram en modell för plockanalys som kan användas som en del av denna uppföljning samt testat densamma. I grundsystemet finns tre fraktioner: Komposterbart, brännbart och övrigt. Det avfall som dag omfattas av producent ansvaret ska konsumenterna själva transportera till uppsamlingsplats/ återvinningsstation. De krav Falu kommun ställde på provtagningen var: Provtagningsmodellen avser endast material som omfattas av det kommunala ansvaret Provtagningen skall ske vid behandlingsanläggningen Provtagning skall göras så att det är möjlig att jämföra hur en- och flerfamiljshushåll sorterar. Plockanalysen skulle visa hur: rena fraktionerna är och vad ev. föroreningar utgörs av. stor andel av påsarna som var helt osorterade/gravt felsorterade. stor andel av hushållsavfallet som utgörs av material som omfattas av producentansvaret. viktfördelningen mellan elva fraktioner. Prov togs tre ggr per fraktion och områdestyp. Proverna delades ned till lämplig storlek för analys genom rutprovtagning vid behandlingsanläggningen. Skrymdensiteter för källsorterat hushållsavfall beräknade i samband med provtagning. Beräkningarna visade på relativt små skillnader mellan densiteter från en- resp. flerfamiljshus. 126 kg/m3 för avfall från enfamiljshus och 101 kg/m3 för avfall från flerfamiljshus. Hushållen producerade i snitt ca 7 kg avfall per vecka (en- och flerfamiljshus), varav 3.0 (enfamiljshus) och 2.4 (flerfamiljshus) kg organiskt avfall. Det fanns vissa skillnader i (funktionell) renhet mellan en- och flerfamiljshushållen. Den funktionella renheten var högst i den komposterbara fraktionen från enfamiljshus, 98% som skall jämföras med 96% för flerfamiljshushåll. Inom den brännbara fraktionen fanns inga mätbara skillnaderna, den funktionella renheten var 97% för både en- och . flerfamiljshushåll. Restavfallet från flerfamiljshushåll hade en rättsorteringsgrad på 9% och restavfallet från enfamiljshushåll innehöll endast 8% rättsorterat material. Återvinningsgraden för komposterbart material låg mellan 66-78%, för brännbart på mellan 74-80%.

  • 169.
    Mattsson Petersen, Cecilia
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Berg, Per E O
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    The Development of Systems for Property Close Collection of Recyclables: Experiences from Sweden and England2003In: Resources, Conservation and Recycling, ISSN 0921-3449, E-ISSN 1879-0658, Vol. 38, no 1, p. 39-57Article in journal (Refereed)
    Abstract [en]

    This study presents a multiple case study of systems for collection of recyclables from domestic properties. A model for describing the development process is presented together with six examples from Sweden and one from the UK. Six Swedish systems that have been in operation since 1994, when the Ordinance on Producers' Responsibility was enforced, are presented. They are considered in the light of the driving forces behind their development: co-operation between municipality and producers, collection efficiency through vehicle development, quality of recyclables, Agenda 21 and environmental concerns, service to users and recycling as a marketable product, respectively. The Swedish systems are compared to a recently introduced collection program in Northamptonshire, UK. The results from an evaluation of the Swedish systems shows that what differentiates them is not technical details but how, where, by and for whom they were developed. The conclusion drawn is that a collection system should be adapted to local conditions, both in technical design and social factors. At present the lessons from Sweden are being used to design new recycling strategies in Northamptonshire, demonstrating the importance of international comparisons to develop 'best practice'.

  • 170.
    Mattsson Petersen, Cecilia
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Berg, Per E O
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Nordlander, Svante
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Rönnelid, Mats
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Kartläggning av organiskt avfall2004Report (Other academic)
  • 171. Meir, Michaela
    et al.
    Mathisen, Oyvind
    Rekstad, John
    Schakenda, Janet
    Fiedler, Frank
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Facade integration of polymeric solar collectors2005In: Northsun, Vilnius, 2005Conference paper (Other academic)
    Abstract [en]

    The present paper examines building integrated solar collectors with absorbers of polymeric materials. Efficiency measurements of façade-integrated collectors with non-selective black and spectrally selective coloured absorbers are carried out. The performance of the polymeric absorber was compared with solar glass and polycarbonate twin-wall sheets as collector cover. Simulations demonstrate a high solar fraction for a solar combisystem with façade collectors for a well-insulated house in a Nordic climate. Two examples of house concepts with façade collectors are presented which address a new type of customer than the solar enthusiasts with special interest in renewable energy

  • 172.
    Mustafa, Fares
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Optical and thermal performance of load adapted collectors: Optical modelling of two load adapted collectors2002Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    In northern climate it is difficult to attain high yearly solar fractions, due to the combination of high load and low insolation in winter. Attempts to increase collector area result in additional costs and overheating problems. Collectors with internal reflectors present one possible solution of matching the load over the seasons and the available solar insolation and eliminate the overheating problems during the summer. This thesis work presents analytical methods to describe the optical efficiency of LACs (Load Adapted Collector) for beam, diffuse and ground reflected radiation. The optical design is based on the angular distribution of the irradiation, the load, temperature levels and the angular dependent optical efficiency. Two collectors LAG I and LAG II have been built according to the modelling results. The first collector model LAC I consists of two troughs, while the second collector model LAC II consists of four troughs. The two collector models have a concentration ratio of 3. The optical performance of load adapted collectors LACs is mainly dependent on collector geometry. With this dependency on collector geometry, we have with this kind of collectors high optical efficiency during the spring, autumn and as high as possible during the winter and low optical efficiency during the summer. This variation of optical efficiency creates the aimed seasonal variation of collector output. The calculated optical performance of LAC I and LAC II is described by ?0,beam,h 1)=0.73, ?0,beam,L 2)=0.24, ?0,beam,h =0.64, ?0,beam,L =0.41, for both of them respectively. 1) Optical efficiency at high incidence angle. 2) Optical efficiency at low incidence angle.

  • 173.
    Ng'wandu, Evarist L.N.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Development of a cost effective solar cooker2001Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    The purpose of this thesis is to conduct a research study of parabolic solar cookers and to find simplified methods of developing such cookers in order to reduce production time and cost, labour cost and end-sale cost. Also treated in this study are anthropological issues, solar cooker economics, experiments and measurements and a comprehensive literature study. It is observed that solar cookers if properly studied, developed, introduced and provided proper education and training could offer a partial solution to the problem faced by the people in the world who lack energy for cooking food and other related energy services.

  • 174.
    Nordlander, Svante
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Load Adapted Solar Thermal Combisystems - Optical Analysis and Systems Optimization2004Licentiate thesis, monograph (Other academic)
    Abstract [en]

    In a northern European climate a typical solar combisystem for a single family house normally saves between 10 and 30 % of the auxiliary energy needed for space heating and domestic water heating. It is considered uneconomical to dimension systems for higher energy savings. Overheating problems may also occur. One way of avoiding these problems is to use a collector that is designed so that it has a low optical efficiency in summer, when the solar elevation is high and the load is small, and a high optical efficiency in early spring and late fall when the solar elevation is low and the load is large.The study investigates the possibilities to design the system and, in particular, the collector optics, in order to match the system performance with the yearly variations of the heating load and the solar irradiation. It seems possible to design practically viable load adapted collectors, and to use them for whole roofs ( 40 m2) without causing more overheating stress on the system than with a standard 10 m2 system. The load adapted collectors collect roughly as much energy per unit area as flat plate collectors, but they may be produced at a lower cost due to lower material costs. There is an additional potential for a cost reduction since it is possible to design the load adapted collector for low stagnation temperatures making it possible to use less expensive materials. One and the same collector design is suitable for a wide range of system sizes and roof inclinations. The report contains descriptions of optimized collector designs, properties of realistic collectors, and results of calculations of system output, stagnation performance and cost performance. Appropriate computer tools for optical analysis, optimization of collectors in systems and a very fast simulation model have been developed.

  • 175.
    Nordlander, Svante
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Maximum concentration for ideal asymmetrical radiation concentrators2005In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 79, no 5, p. 566-567Article in journal (Refereed)
    Abstract [en]

    A new relation between the maximum geometric concentration factor C and the angular acceptance interval for asymmetrical ideal non-imaging concentrators is proposed. A generalization of the well-known relation for the two-dimensional case, sin ?c = 1/C where ?c is the acceptance half-angle, results in the proposed relation sin ?2 -sin ?1 = 2/C , where ?1 and ?2 are the angles of the acceptance interval limits relative to the normal of the entrance aperture. The proposed relation is valid for any ideal 2D concentrator, symmetrical or asymmetrical. A proof based on conservation of phase space is provided.

  • 176.
    Nordlander, Svante
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Ramprogram solfångarutveckling och systematik. FoU 1997-1999. Slutrapport BFR projekt 199606051999Report (Other academic)
    Abstract [sv]

    Man kan förbättra energibesparingen på årsbasis för ett traditionellt svenskt kombisolvärmesystem från knappt 20 % för ett referenssystem till över 25 %. Alla de studerade systemen har 10 m2 solfångare, lika stor tank, och samma värme- och tappvarmvattenlast. Skillnaderna består endast i systemutformning. Arbetet har utförts genom mätningar i värmelaboratorium och simuleringsberäkningar. Inom området optisk design av solenergisystem har metoder utvecklats för: - analys av solinstråningens himmelsfordelning och asymmetriska årsfordelning - optimering av sollangare med reflektorer - optimering av solceller med tillsatsreflektorer Programmet PRESIM, grafisk indatabehandlare till simuleringsprogrammet TRNSYS, har vidareutvecklats i linje med användarnas önskemål, men förutsättningarna för fortsatt utveckling har försämrats. En förbättrad version, delvis finansierad av Statens energimyndighet och anpassad till TRNSYS 15.0, kommer att släppas under år 2000, men därefter kommer aktiviteten att ligga på en lägre nivå.

  • 177.
    Nordlander, Svante
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    TRNSYS model for Type 210. Pellet stove with liquid heat exchanger. Documentation of model and parameter identification2003Report (Other academic)
  • 178.
    Nordlander, Svante
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Lorenz, Klaus
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Economic Analysis of Combisystems for High Solar Fractions2003In: ISES Solar World Congress, Göteborg, Sweden, 2003Conference paper (Other academic)
  • 179.
    Nordlander, Svante
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Persson, Tomas
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Evaluation and computer modelling of wood pellet stoves with liquid heat exchangers2003In: presented at ISES Solar World Congress, Göteborg, Sweden, 2003Conference paper (Other academic)
    Abstract [en]

    The pellet consumption for single family house heating in Sweden is increasing strongly. Pellet stoves and boilers for domestic heating are becoming increasingly popular and new stove models with gas-liquid heat exchangers have entered the market. There is a need for computer models of the stoves, in order to perform simulation studies. The objective of this work was to evaluate pellet stoves and to make mathematical models of them for use in simulations of heating systems with TRNSYS. Three pellet stoves, one traditional and two with gas-liquid heat exchangers, and one pellet burner were tested in a combustion laboratory. A mathematical two-node model of a stove was developed and implemented as a TRNSYS component. A number of heat transfer coefficients and thermal masses of the stoves were identified. The calculated performance of the stoves agreed well with the measured data. The stove model was used in extensive TRNSYS simulations of yearly performance of single-family house heating systems. The simulations showed that the emissions, the yearly efficiency of a stove and the savings of auxiliary electric energy for heating may vary significantly depending on system design and control strategy.

  • 180. Nordlander, Svante
    et al.
    Persson, Tomas
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Fiedler, Frank
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Rönnelid, Mats
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Computer modelling of wood pellet stoves and boilers connected to solar heating systems2006In: Proc on USB of Pellets 2006, 30 May - 1 June, Jönköping, Sweden, Jönköping, Sweden, 2006Conference paper (Other academic)
    Abstract [en]

    When optimizing systems for wood pellet and solar heating, there is a need for realistic computer models of stoves and boilers in order to perform simulation studies. The objective of this work was to develop and verify a mathematical model for wood pellet stoves and boilers for use in system simulations with TRNSYS calculating both the energy balance and CO-emissions (carbon monoxide). Laboratory measurements have been carried out on three pellet stoves, one traditional and two with gas-liquid heat exchangers, and four pellet boilers. A mathematical two-node model of a stove was developed and implemented as a TRNSYS component. Parameters were identified for two stoves and three boilers. This new model makes it possible to perform detailed simulations with time steps less than a minute of complete wood pellet heating systems and to derive long term values, such as annual values, of efficiency and emissions for the boiler or stove in a system context under realistic conditions. In addition, parametric studies can be used in order to investigate how different operation principles and system design affect these values. The simulated energy balance of a water jacketed stove investigated in this work agreed well with measured data during both stationary and dynamic conditions.

  • 181. Nordlander, Svante
    et al.
    Rönnelid, Mats
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Load Adapted Collectors for High Solar Fractions2001In: North Sun, Leiden, The Netherlands, 2001Conference paper (Other academic)
  • 182.
    Nordlander, Svante
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Rönnelid, Mats
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Solvärmesystem för hög täckningsgrad - Load adapted concentrating collectors for high solar fractions2004Report (Other academic)
    Abstract [sv]

    Dagens kombisolvärmesystem för enfamiljshus har i storleksordningen 10 m2 solfångare och kan täcka i runda tal 10 ? 30 % av det årliga värmebehovet. Ökar man solfångarytan för att öka solvärmetäckningsgraden uppstår det vanligtvis en överproduktion av värme sommartid viket kan orsaka problem i form av termisk utmattning av material, att material förstörs eller att säkerhetsventiler utlöses med driftsstopp som följd. Vidare förkortas glykolens livslängd radikalt och detta kan ge följdskador såsom korrosion, beläggningar i rören och t o m igensättning av systemet. Ett sätt att undvika problemen med överhettning i solvärmesystem med hög täckningsgrad är att använda lastanpassade solfångare. Med detta menas solfångare som har en verkningsgrad som är beroende av solhöjden och varierar över året. Verkningsgraden är hög när värmelasten är hög (vanligtvis sen höst, vinter och tidig vår) medan verkningsgraden är låg då värmelasten är låg (vanligtvis sen vår, sommar och tidig höst). I denna rapport visas att det är möjligt att bygga lastanpassade solfångarsystem med hög täckningsgrad för enfamiljshus med solfångarytor som täcker hela villatak (>= 40 m2), utan att den termiska påfrestningen på systemet blir större än för vanliga solvärmesystem med 10 m2 plana solfångare. Detta kan göras med samma systemkomponenter som finns i system med plana solfångare. De lastanpassade solfångarna levererar ungefär samma energimängd per m2 som plana solfångare, men de bör kunna bli billigare, på grund av lägre materialkostnad. Det finns även en potential att konstruera lastanpassade solvärmesystem med begränsad stagnationstemperatur, vilket kan möjliggöra användandet av billigare material. En och samma solfångartyp är lämplig för såväl stora som små system och för olika takvinklar. I rapporten redovisas optimerade solfångargeometrier för lastanpassade solvärmesystem, geometrier och optiska egenskaper för praktiskt möjliga solfångare samt beräkningar av förväntat årsutbyte, stagnationstemperaturer, stagnationstider och kostnader. Testresultat för två prototyper av lastanpassade solfångare presenteras. Optimeringsalgoritmer för design av optiken för lastanpassade solfångare i system samt ett ray-tracingverktyg och snabba men ändå tillräckligt noggranna simuleringsverktyg har utvecklats.

  • 183. Nordlander, Svante
    et al.
    Rönnelid, Mats
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Broman, Lars
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Isakson, Per
    Figueroa, Eduardo
    PRESIM - a graphical interactive preprocessor for modular simulation programs1989In: North Sun´88, Borlänge, 1989Conference paper (Other academic)
  • 184. Nordlander, Svante
    et al.
    Rönnelid, Mats
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Isakson, Per
    Broman, Lars
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Presentation of PRESIM - a user-friendly preprocesssor for TRNSYS1990In: North Sun´90, Reading, 1990Conference paper (Other academic)
  • 185. Nordlander, Svante
    et al.
    Rönnelid, Mats
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Isakson, Per
    Broman, Lars
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Presentation of PRESIM. A userfriendly pre-processor for TRNSYS1991In: Nordic Solar Energy R & D Meeting, Borlänge, 1991Conference paper (Other academic)
  • 186.
    Nordlander, Svante
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Rönnelid, Mats
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Isakson, Per
    Broman, Lars
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    PRESIM - a graphical interactive preprocessor for modular simulation programs1989In: ISES Solar World Congress, Kobe, Japan, 1989Conference paper (Refereed)
    Abstract [en]

    PRESIM is a computer program for creating, storing, retrieving and changing input data for modular HVAC programs. The user works with CAD-style tools. The program also produces system schematics and other documentation. A first release of PRESIM will produce input data for the TRNSYS program.

  • 187. Nordlander, Svante
    et al.
    Rönnelid, Mats
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Karlsson, Björn
    Load and Season Adapted Solar Collectors2000In: Eurosun 2000, Copenhagen, Denmark, 2000Conference paper (Other academic)
    Abstract [en]

    In Sweden solar irradiation and space heating loads are unevenly distributed over the year. Domestic hot water loads may be nearly constant. Test results on solar collector performance are often reported as yearly output of a certain collector at fixed temperatures, e g 25, 50 and 75 C. These data are not suitable for dimensioning of solar systems, because the actual performance of the collector depends heavily on solar fraction and load distribution over the year. At higher latitudes it is difficult to attain high solar fractions for buildings, due to overheating in summer and small marginal output for added collector area. Solar collectors with internal reflectors offer possibilities to evade overheating problems and deliver more energy at seasons when the load is higher. There are methods for estimating the yearly angular irradiation distribution, but there is a lack of methods for describing the load and the storage in such a way as to enable optical design of season and load adapted collectors. This report describes two methods for estimation of solar system performance with relevance for season and load adaption. Results regarding attainable solar fractions as a function of collector features, load profiles, load levels and storage characteristics are reported. The first method uses monthly collector output data at fixed temperatures from the simulation program MINSUN for estimating solar fractions for different load profiles and load levels. The load level is defined as estimated yearly collector output at constant collector temperature divided be yearly load. This table may examplify the results: Collector Load Load Solar Improvement type profile level fraction over flat plate Flat plate DHW 75 % 59 % Load adapted DHW 75 % 66 % 12 % Flat plate Space heating 50 % 22 % Load adapted Space heating 50 % 28 % 29 % The second method utilises simulations with one-hour timesteps for collectors connected to a simplified storage and a variable load. Collector output, optical and thermal losses, heat overproduction, load level and storage temperature are presented as functions of solar incidence angles. These data are suitable for optical design of load adapted solar collectors. Results for a Stockholm location indicate that a solar combisystem with a solar fraction around 30 % should have collectors that reduce heat production at solar heights above 30 degrees and have optimum efficiency for solar heights between 8 and 30 degrees.

  • 188.
    Nuo, Cheng
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    SERC Solar Simulator: Outdoor tests and indoor tests comparison2005Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    Solar Energy is one of the clean new energy fuels. Nowadays energy sources like petrol and coal become less and less, faced with a possibility of scarce oil resources, so those new energy sources like wind, tide and solar energy become more and more popular. Most manufactures and solar energy research centers try to design and develop the solar energy facilities with high quality and efficiency, but the weather problems always impact their outdoor testing. So the solar simulator has been invented for testing indoor instead of outdoor when meet the poor weather without sunshine. Solar simulator is mainly made up of solar lamps, which have close spectral distribution, color temperature and luminance intensity to natural Sun. In this project, most of the popular solar lamps and its relative equipments would be investigated and purchase one of the type from Swedish suppliers. After the solar simulator installed in SERC Laboratory, several experiments would be test (Basic on PV panel, Thermal collect system, Solar cooker), and also test those experiments outdoor, compare those experiments, make evaluation and give suggestion of development with those lab-work for future study of SERC. For the measurements, the PV test got worse results than outdoor, thermal collector and solar cooker both got better results than outdoor (detail in Report and Discussion part) Also the radiation distributions have been test for the SERC solar simulator, the simulator operated with stable radiation source but the radiation got uneven value (the radiation got strong where close to the centre of illuminated surface and weak where far away from the centre).

  • 189.
    Nygren, Ingemar
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Inventering av eluppvärmda småhus i Sverige, samt val av typhus2003Report (Other academic)
  • 190.
    Olsson, Christer
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Cost Analysis on Solar Powered Radio Base Station with Cooling Demand2002Independent thesis Advanced level (degree of Master (Two Years))Student thesis
  • 191.
    Paavilainen, Janne
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    TCA TrnSys Model2005Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    This thesis is part of a research project about a novel type of absorption chiller, the Thermo Chemical Accumulator (TCA), an invention patented by Solsam Sunergy AB, Sweden. The work was done at the Solar Energy Research Centre (SERC) in Bor-länge, Sweden, in cooperation with Solsam Sunergy AB and Vattenfall Energi. The aim of the project was to make a simulation model of the system and further make simulations with the model. The model of the TCA was made based on measurements made on a prototype TCA-system. First a crude model of the TCA was made in a spreadsheet application and this was then implemented in TrnSys. In TrnSys the TCA-model was expanded to include a building as cooling load, solar thermal collector as driving heat source, cooling coils as outside coolers and weather data readers for simulating different cli-mates. Parametric studies were made to find out the performance of the system. The main parameters varied were: load type (office/domestic), collector size, outside cooler size, air conditioning unit size and storage size. It was found that the sizing of the air conditioning unit has a critical influence on the cooling output of the system; in the TCA the outlet cooling temperature depend on the ambient temperature and commercial air conditioning units are usually dimen-sioned for temperatures lower than the available outlet temperatures from the TCA during hot days. The outside coolers were found to be of sufficient size. The storage size was not found to limit the solar fraction. But as only short term storage was stud-ied, the conclusion holds only for this case. The COP of the system was found to be around 0.65 with steady state operation or short term storage, which is a normal value for current absorption refrigeration technologies.

  • 192.
    Pei, Gao
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Modeling and Heat Deamnd Calculations for Two Type Houses and Integration of the SolarNor Solar Heating System2005Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    Among the ongoing research projects at SERC (Solar Energy Research Center) there is one Nordic collaboration project called REBUS (Competitive Solar Heating Systems for Residential Buildings). The objective of this project is the development of competitive solar heating systems for residential buildings in northern latitudes. This is part of a European wide collaboration for developing the next generation of solar thermal systems. The project partners are located in Riga, Copenhagen, Lund and Oslo, where country specific conditions for the development of the systems are taken into account. This thesis project was carried out at department of physics in University of Oslo (UiO) in Norway and Högskolan Dalarna SERC in Sweden. Solar system developing company SolarNor has collaboration with the prefab-house manufacturer Systemhus for the integration of solar heating systems. Norwegian company Systemhus has designed new series family houses named Karakter. There are several types of low energy houses. Karakter type 3 and Karakter type 4 is interested in install solar floor heating system, and most studied in this thesis work. The results of modeling are used to draw conclusions for design of the heating system and the optimal orientation of the building as well as the placement of the façade integrated solar collectors. The purpose of this thesis work is to modeling and heat demand calculations for type houses and adoption of the SolarNor solar heating system for those houses. The energy consumption of these buildings has been investigated by modeling the buildings simulation with computer software IDA /1/ and Prebid /2/. For adoption of the SolarNor solar collector, SolDat simulation program has given the valuable results of the façade integrated solar collectors. Through the energy calculation and economic evaluation, 21 m2 collector area installing on southern façade 4 is recommended for the optimal adoption of SolarNor solar collector for Karakter types houses

  • 193.
    Perers, Bengt
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Mätning och utvärdering av nya Mareco 1000 Solvärmefält i Torsåker hösten 20032003Report (Other academic)
  • 194.
    Perers, Bengt
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    A Solar Collector Model for TRNSYS Simulation and System Testing2002Report (Other academic)
  • 195. Perers, Bengt
    et al.
    Karlsson, Björn
    Rönnelid, Mats
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    An improved Dynamic Test Method for the Determination of Non-Linear Incidence Angle Modifiers from Outdoor Testing using Standard Multiple Regression Tools1996In: EuroSun 1996, Freiburg, Germany, 1996Conference paper (Other academic)
  • 196.
    Perers, Bengt
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Kovacs, P.
    Olsson, M.
    Persson, M.
    Pettersson, U.
    A new tool for standardized collector performance calculations2011Conference paper (Refereed)
    Abstract [en]

    A new tool for standardized calculation of solar collector performance has been developed in cooperation between SP Borås Sweden, DTU Denmark and SERC Dalarna University. The tool is designed to calculate the annual performance for a number of representative cities in Europe on the basis of parameters from collector tests performed according to EN12975, without any intermediate conversions. The main target group for this tool is test institutes and certification bodies that intend to use it for conversion of collector model parameters derived from performance tests, into a more user friendly quantity i.e. the annual energy output. Energy output both per m2 and per collector module can be calculated.

  • 197.
    Perers, Bengt
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Kovacs, P.
    Pettersson, U.
    Experiences and lessons learned from 30 years of dynamic collector testing, modelling and simulation2011Conference paper (Refereed)
    Abstract [en]

    Dynamic testing and modeling (in contrast to Steady State line of action) of solar collectors is to prefer in most climates, except for the most extreme locations with clear skies every day. A very important part of dynamic testing and modeling is not only the thermal capacitance correction, but also the split of the solar radiation absorption modeling, into beam and diffuse and the modeling of the collectors' incidence angle dependency for both beam and diffuse radiation. These optical features are in most situations more important than the accuracy of the dynamic and thermal loss part of the model. This can be seen from the statistical analyze when evaluating test data. The t-ratios i.e. the parameter values divided by their standard deviations, are generally much higher (often 10 times higher) for the optical parameters than for the thermal loss ones. There are also important details concerning solar radiation measurements for beam and diffuse including alignment of sensors and test object, that are often not considered, which will be discussed and lessons learned will be given. A misalignment of just a few degrees of the collector test stand or the solar sensors will immediately show up in a dynamic test evaluation, especially when analyzing the incidence angle modifier behavior and thermal capacitance of a collector. To achieve good results in dynamic testing it is essential to understand the basic concepts of the method and to use this understanding when designing a test rig and collecting data during a test for later analyze. It is very desirable to use a continuous parameter feedback during the test, so that the test conditions can be changed hour by hour to derive more accurate results and shorten the testing time. Such advice will be discussed in the paper. Some of these findings has not yet reached the EN12975 standard level, and suggestions for revisions and improvements will be presented that have general application also for non standardized testing, for example research and development testing.

  • 198.
    Perers, Bengt
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Kovacs, P.
    Pettersson, U.
    Björkman, J.
    Martinsson, C.
    Eriksson, J.
    Validation of a dynamic model for unglazed collectors including condensation: Application for standardised testing and simulation in TRNSYS and IDA2011Conference paper (Refereed)
    Abstract [en]

    An improved unglazed collector model has been validated for use in TRNSYS and IDA and also for future extension of the EN12975 collector test standard. The basic model is the same as used in the EN12975 test standard in the QDT dynamic method. In this case with the addition of a condensation term that can handle the operation of unglazed collectors below the dew point of the air. This is very desirable for simulation of recharging of ground source energy systems and direct operation of unglazed collectors together with a heat pump. The basic idea is to have a direct connection between collector testing and system simulation by using the same dynamic model and parameters during both testing and simulation. The model together with the parameters will be validated in each test in this way. This work describes the method applied to an unglazed collector operating partly below the dew point under real dynamic weather conditions, for a long period during the autumn 2010. The validation results also show that the model can handle operation of such a collector during the night. This is a common mode of operation for this collector type in a real system.

  • 199.
    Perers, Bengt
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Lorenz, Klaus
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Rönnelid, Mats
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Partiell förångning i solfångarsystem: överhettningsskydd för värmebäraren (främst glykol)2003Report (Other academic)
  • 200. Perers, Bengt
    et al.
    Spante, Lars
    Krohn, P
    Setterwall, C
    Gröndalen, O
    Holmström, S
    Selhagen, L
    Sandell, P
    Andersson, M
    Stolt, L
    Wennerberg, J
    Sterner, J
    Rönnelid, Mats
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Forssander, M
    Sandberg, B
    Björk, D
    Solceller 19961996Report (Other academic)
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