du.sePublications
Change search
Refine search result
123456 101 - 150 of 292
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • chicago-author-date
  • chicago-note-bibliography
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 101.
    Henning, Annette
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Socialantropologiska teorier applicerbara på solenergiteknik: Del 1 Föremåls föränderliga kulturella värde1996Report (Other academic)
  • 102.
    Henning, Annette
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Socialantropologiska teorier applicerbara på solenergiteknik: Del 2 Diskussion av mikro- och makroperspektiv1996Report (Other academic)
    Abstract [sv]

    Denna skrift färdigställdes i augusti -96. De metoder som redogörs för i rapporten har använts i ett socialantropologiskt translokalt fältarbete som pågått periodvis under loppet av en fyraårsperiod. Dessa metoder, liksom de teorier som tas upp här, är utvalda för att användas i en kommande doktorsavhandling om försöken att integrera solenergiteknik i det svenska samhället (Solenergiteknik diskuteras emellertid inte explicit i denna rapport. För en närmare redogörelse av det pågående avhandlingsarbetet se Socialantropologisk studie av solenergiteknikers införande i Sverige. Projektpresentation oktober 1995, arbetshandling SERC). Jag förespråkar i rapporten en användning av begreppen nätverk och process som metod- och analysredskap. Jag för också fram en kulturteori som utgör en samlad syn på de teoretiska begreppen kultur, struktur och process. Dikotomin mellan individ och samhälle försvagas här kraftigt, både genom mitt sätt att använda kulturbegreppet och genom min användning av begreppet struktur .Denna kulturteori inbegriper såväl idémässiga, sociala som materiella förhållanden och är samtidigt en teori om förändring. Jag framför här också ett förslag till två lämpliga målsättningar för att föra socialantropologiska mikro- och makroperspektiv närmare varandra. Den ena målsättningen innebär att man vid teoretiska mer generaliserande beskrivningar av förhållanden i världen bör sträva mot att uttrycka sig så att dessa beskrivningar också blir applicerbara på specifika fältarbeten. Detta innebär både att de begrepp som används ska vara bra redskap att tänka med för antropologen i fält, och att de makroteoretiska resonemang som förs i allt högre utsträckning bygger på fältarbeten som på varierande sätt inkluderar globala skeenden. Den andra målsättningen gäller fältarbetet och beskrivningen av detta. Här menar jag att också fältarbeten behöver planeras, utföras och presenteras så att sådana fältarbeten tillsammans kan ingå i det makroantropologiska projektet att skapa underlag för makroteorier om förhållanden i världen. Min avsikt är att i mitt eget avhandlingsarbete använda mig av teoretiska begrepp och metodologiska tillvägagångssätt som överensstämmer med dessa två målsättningar.

  • 103.
    Henning, Annette
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Solvärme och svenska vanor2003In: Hett om kalla fakta. Aktuell forskning om temperaturen, människan och naturen, Vetenskapsrådet , 2003Chapter in book (Other academic)
    Abstract [sv]

    Hur bör värmesystem utformas för att passa svenska vanor? Människors inställning till solfångare och pelletskaminer speglar faktiskt hur vi förhåller oss till temperatur. Aktuell socialantropologisk forskning kan här bidra med fruktbara perspektiv.

  • 104.
    Henning, Annette
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Tio hushåll om elkonvertering. Hem och härd, del II2003Report (Other academic)
  • 105.
    Henning, Annette
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Lorenz, Klaus
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Flexibla lösningar som strategi för ökad anslutningsgrad.2005Report (Other academic)
  • 106.
    Hu, Jin
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    A CFD Study of the Convection Aspect of PCMs in the Water Tank of a Solar Combisystem2005Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    Solid/liquid phase change process has received great attention for its capability to obtain high energy storage density. In this project, to analyze a simplified system undergoing liquid-solid phase change in presence of forced convection and natural convection, a commercial CFD code FLUENT has being utilized. The thermal and heat transfer characteristics of paraffin wax and sodium acetate plus graphite were investigated in simulation. The performance of these two phase change materials in the discharge process was characterized; the existence of natural convection during the solidification of paraffin wax was visualized and characterized. Solidification of paraffin wax and sodium acetate plus graphite were visualized and characterized by means of density changes. The simulation results indicate that paraffin wax and sodium acetate plus graphite have quite different thermal performance under the same working conditions; phase change of paraffin wax will affect the velocity of solid-liquid interface; porous graphite can greatly improve the heat transfer of sodium acetate/graphite composite. In the final part of this project, the numerical results are validated by comparing with experimental data. There is a good agreement between simulations and experiments.

  • 107.
    Händel, Robert
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Market and literature study on technologies for seasonal storage of solar energy regarding small-scale applications, with focus on thermochemical storage2001Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    A problem of using solar thermal energy is the seasonal time difference between high gained solar energy in the summer and low gained solar energy in the winter. The load of warm water is constant over the year and even increasing, if the solar system is used for domesting heating. With seasonal energy storage this problem would be solved.

  • 108.
    Igbinweka, Monday Isoken
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    The Solar Lantern and Battery Options Photovoltaic Technologies2004Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    Although electric energy is cheap and plentiful in developed countries, it is still very much a luxury in much of the rest of the world. In order to illuminate their homes and communities after dark, most families are forced to rely on candles or kerosene, neither of which is very safe, economical, or provides a steady, clean source of light. In recent years, there has been significant progress made to utilise sunlight, one of the most abundant and economical sources of energy available and the study and development of photovoltaic technologies which have enabled the conversion of this solar energy into a reliable, storable electric light. In Karagwe District, Tanzania, a non-governmental organization called the Karagwe Development Association (KARADEA) brought this technology to East Africa through the KARADEA Solar Training Facility (KSTF). It was through this organization that solar-powered lanterns were introduced to the general population here. Unfortunately, although the lanterns had an anticipated lifespan of several years, most were returned to the facility within six months with the explanation that they no longer worked. It is the goal of this paper to determine the cause for the severely reduced lifespan of these lanterns, and to propose how this technology might better serve the populations who most need it most. To ensure a complete understanding of the technology, a thorough explanation is undertaken of each of the main components of the photovoltaic system: the photovoltaic generator (i.e. the solar cell), the battery, the charge controller and the load (in this particular examination, the lantern). Ideally, the research would have been carried out on location in Tanzania, but due to financial constraints, this was not possible. Two of the incapacitated lanterns that had been returned to the KSTF were sent to be studied in the laboratory at SERC, and correspondence between the author and various members of this NGO provided the basis for the research conducted and subsequently reported in this paper. The lanterns sent for study from Tanzania underwent detailed examination and testing regimens, which, when combined with the details provided by the first-hand users at the KSTF, provided several suggestions as to the possible problem that had initially caused the breakdown of these devices. These possibilities are then examined in greater detail and held up alongside the results of several laboratory experiments to arrive at what appears to be the primary cause of the breakdown of the lanterns: a malfunctioning charge controller. Finally, in conclusion, there are several suggestions that should be considered by both the end users and manufactures of such devices to facilitate their longevity, as well as some suggestions of future potential work in this field.

  • 109.
    Irisarri, Pablo Armendariz
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Climatization of a Laboratory by TCA Technology in Spain2004Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    The Thermo Chemical Accumulator is a new heat pump based on absorption technology with LiCl-water working pair that provodes heating or cooling as wanted, using for that thermal energy that has previously has been stored in the device. Solar thermal energy seems to be a very good option as energy source for supplying the machine. The device is still under development but the company owner of the patent (Climate Well) is starting its commersialisation. The first commercially available device based on TCA technology has been called DB 220, which is essentially production prototype. Due to the characteristics of the machine it can be specially useful in Mediterranean climates. That is why Clime Well is interested in introducing the technology in the Spanish market. The main aim of this thesis work has been to make a specific case study of the installation that will include the first DB 220 in Spain. For that purpose, first of all a learning process about the TCA technology as well as about air conditioning in general has been done. A state of the art of thermally driven cooling technologies in Spain is presented in this thesis work as well as a detailed description of the TCA technology and the best air conditioning possibilities for it. It has to be underlined that the behaviour of the TCA and thus the charging rates that can be reached as well as the discharging ones for heating and cooling are very dependent on the selected peripheral devices that are used with the machine. Solar thermal collectors seems to be a very good option for providing the thermal energy to the machine together with radiative floor or ceiling for the distribution system of air conditioning and geothermal circuits for heat rejection/absorption when providing cooling/heating, respectively.

  • 110.
    Irukulla, Anand Kumar
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Chatacterization of Mono-crystalline Silicon Solar Cells Using Different Methods2003Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    This thesis explores various methods of characterizations for mono crystalline silicon solar cells. Within this study, known analysis techniques have been utilized to characterize solar cell efficiency and the effect of certain processing steps on the resulting cells. Specifically, the importance of IU curve measurements, Werner plots of resistance, and internal quantum efficiency are evaluated, and various optimizations schemas are investigated. This study therefore works to further the goals of device efficiency maximization, and device parameter analysis; the eventual goal being the optimization of the fabrication peocess and characterization of the behaviour of the new diffusion furnace at IPE (University of Stuttgart). Additionally, using a simulation program (IQET) emitter thickness was determined for various samples, based on the internal quantum efficiency. These results than provide a greater understanding of the importance of the emitter thickness, and the necessary steps to optimize this thickness. From internal quantum efficiency, diffusion length is also determined, leading to a greater understanding of our capabilities and limitations in producing higher efficiency solar cells.

  • 111. J, Wennerberg
    et al.
    J, Kessler
    J, Hedström
    L, Stolt
    B, Karlsson
    Rönnelid, Mats
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    CIGS thin film PV modules for low-concentrating systems2001In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 69, p. 243-255Article in journal (Refereed)
  • 112.
    Jallade, Nicolas
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    A heat use concept for the EMA-collector in combination with a heat pump and a borehole store2000Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    The principle of the elastomer-metal-absorber (EMA) can be described as the tight connection of elastomer fluid tubes clipped in appropriately shaped metal profiles, acting as solar absorbers. This new kind of solar collector will be developed within an EU-project with partners from Austria, Germany, and Sweden. Several prototypes as well as test systems have to be built and evaluated. One important item, within the project, is to find suitable heat use concepts for the elastomer-metal-absorber. Therefore, the investigations in Sweden will be concentrated on combinations of this new collector with heat pumps and any kind of ground storage. Based on system simulations with the program TRNSYS, the most promising concepts will be designed and installed at SERC. The main objective of this thesis was to find the best solution for a combination of the EMA with a heat pump and bore hole storage. Therefore simulations were carried out with different heat pumps as well as with different designs of the bore hole. The optimisation of the ground storage became an especially important part of this work. Finally, the influence of characteristic parameters of the model that was used for the bore hole has been analysed. The investigations showed that the coefficient of performance of the whole system is much more influenced by different heat pumps than by different designs of the bore hole. The best heat pump led to an increase of the system performance of more than 10% compared with the base case system. However, improved U-pipe bore holes only increased the COP-values by slightly under 4%. Finally, it can be stated that there are still some uncertainties about the simulation model and that only a comparison with the test system that will be built will enable as assessment to be made between model and reality.

  • 113.
    Ju, Zhenhe
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Tibetan Photovoltaic Village System2003Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    The purpose of this thesis work is that to design a stand-alone PV village system in Tibet substituting the old diesel generator to supply electrical loads for Xiangmao village. According to the particularity of Tibet, which is alleged as the highest elevation of the third pole in the world, on the foundation of the investigation for the local region. The method is computer-aided program and parametric analysis on the basis of the local systematical examination and to explore feasibility of the economy and the technology of Tibet PV village system. The work has started from the solar radiation collection for the local data almost 20 years ago, the statistics to the available electrical load of this village and the forecasting coming 3 years load. Theough the collation and calculation to solar radiation data from Naqu radiation station that had complete solar data of 14 years and author determined the optimum tilt angle of array in this PV village and the mean daily each month radiation quantity. By means of this computed results author counted and selected out the capacity of PV array and battery, their optimum combination point and completed optimization of the PV system. As a result, through analysis of the state–of-charge for battery, the PV system parameter becomes more perfect. Finally, the analysis of the technology and economy of the PV village investments is accomplished by means of the renewable energy knowledge.

  • 114. Karlsson, Björn
    et al.
    Helgesson, Anna
    Rönnelid, Mats
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Utveckling av moduler med överliggande refflektorer för fristående solcellssystem för årstidsutjämning och för att undvika snö och frostbeläggning2001Report (Other academic)
  • 115. Karlsson, Björn
    et al.
    Krohn, Peter
    Perers, Bengt
    Krohn, Peter
    Rönnelid, Mats
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Brogren, Maria
    Solceller med reflektorer: Resultat 19992000Report (Other academic)
  • 116. Karlsson, Björn
    et al.
    Krohn, Peter
    Perers, Bengt
    Rönnelid, Mats
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Solceller med reflektorer: Resultat 19971997Report (Other academic)
  • 117. Karlsson, Björn
    et al.
    Krohn, Peter
    Rönnelid, Mats
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Solceller med reflektorer: Resultat 19981998Report (Other academic)
  • 118. Karlsson, R.
    et al.
    Bergeå, Ola
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Berg, Per E O
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Pohl, E.
    Kullin, J-P
    Slutrapport från Rörlighetspilot Dalarna och Rörlighetspilot Kalmar. (Mobility of Key Persons for Promotion of Business Renewal and Sustainable Growth)2004Report (Other academic)
  • 119. Karlsson, R
    et al.
    Bergeå, Ola
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Kulesza, W
    Pontén, Bengt
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Life cycle considerations in the core of business development2003In: CIRP-conference on Life Cycle engineering, Copenhagen, Denmark, 2003Conference paper (Other academic)
  • 120.
    Karra, Ramreddy
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Chintakindi, Naveen
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Active solar heating system with concrete floor heating analysed with dynamic thermal simulation2005Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    A single family house is planned in Sweden with the objective of integrating renewable energies in the heating design. The house is provided with the solar floor and DHW (domestic hot water) heating system with flat plate solar collector. TRNSYS programme is used to simulate the houses (well insulated house and not well insulated house); dynamic simulations are used to confirm the technical feasibility of the studied concept, and to check the utilization of solar power and auxiliary energy. A differential parameter sensitivity analysis is made in an attempt to account for uncertainties in some input parameters like insulation thickness, collector area. It seems that no major improvement in the results expect to say the well insulated house performs well i.e. low heat losses due to good thermal insulation after comparing the results for both the houses. Further in the work annual simulations are performed to the system with possible improvements to achieve desired objective.

  • 121.
    Khan, Ahmad Asim
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Optimisation with industry of a solar heating system using simulations2002Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    This work was a part of IEA Solar Heating & Cooling Program (IEA SHC) Task 26 research, at Solar Energy Research Centre, Högskolan Dalarna. The purpose of this study work was to optimise an existing Swedish solar heating system (#12) using simulations on TRNSYS/Trnsed program. This system has an advanced controller and a store with four heat exchangers: two for the collector loop and two for preparation of hot water. Simulation model has been created as TRNSYS/Trnsed program before this project started, and this program was used to optimise the performance of the model. The boundary conditions for the system optimisation were: climate Zurich (Switzerland), single family house 60 [KWh/a], 10.0 [m2] collector area and stor volume 730 L. No additional costs were to be allowed. The optimisation process include a sensitivity analysis of all relevant parameters in the system. Based on this, a series of different system variations were chosen as possible improvements before the final optimised solution was chosen. An improved performance of the whole system was determined by finding proper inlets, outlets height of connections for the space heating and domestic hot water loop without using any extra material. The results show that for the conditions studied it is not worth to have upper collector heat exchanger in the simulation model so one extra heat exchanger and three valve have been deducted from the combisystem #12. However, one of the features of this system is its attempt to make optimal use of varying radiation conditions and such conditions were not possible to study in this work as only hourly weather data were available. In addition, a study on material demand for this system as well as a similar system, #11 of the IEA SHC Task 26. This data was used to calculate the energy pay-back time for the two systems. It can be used as the basis for possible future LCA studies

  • 122. Kjellsson, E
    et al.
    Hellström, G
    Tepe, R
    Rönnelid, Mats
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Combination of Solar Heat and Ground Source Heat Pump for Small Buildings2003In: Futurestock 2003, Warsaw, 2003Conference paper (Other academic)
  • 123.
    Koepsell, Stefanie
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Grid-connected Photovoltaics in Sweden: Investigation of the Current Situation and a Case Study2005Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    This work deals with with the investigation of grid-connected PV in Sweden. In two different parts, both the current status and a case study are regarded. The prevailing conditions and legislation for PV in Sweden are examined and compared to the European market. Different support measures are explained and exemplified by the development in Germany. A newly introduced incentive for the promotion of PV in Sweden is evaluated. 90% of Swedish electricity is produced by hydropower and nuclear power plants. The proportion of PV energy is with 3.6 MWp (2003) installed capacity negligibly small. In contrast to the developments on the European market, maily off-grid systems are in operation in Sweden. Besides the moderate radiation level traditionally low energy prices and the lack of long-term supportive mechanisms hamper the dissemination of grid-connected PV. Unlike in 16 other European countries no feed-in tariffs are applied. Electricity certificates which will be traded till 2020 in Sweden have proved to be an unsuitable measure for PV. A new law introduced in May 2005 aims at supporting PV on public buildings by giving the owner a 70% investment subsidy as a tax credit. An amount of 100 million SEK (11 million €) will be provided for this incentive till 31.12.2007. This measure seems to be unsuitable due to its short-term character, the restricted target group, uncertainties about future savings and the lack of monitoring facilities. In a case study the detailed steps of a project planning under Swedish conditions are performed. The required components for an 18 kWp PV installation on an existing ridged roof building are dimensioned. The solar generator consists of 84 modules which are connected in an array concept to 3 inverters. A simple mounting structure is suggested. The expected output is determined by the simulation program PVSYST and amounts to 14200 kWh. The results of the economical analysis show that the project is hardly feasible under current Swedish conditions even when the new subsidy is applied.

  • 124.
    Korintus, Gabor
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Use of Solar Energy in Low Cost Housing in De Ar, South Africa2003Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    The housing situation in South Africa needs serious improvement and intervention. There is a huge amount of housing backlog, and the living conditions, housing quality in low-income areas is beneath an acceptable level. The solution at present is considered to be large scale, low-cost housing projects, supported by governmental subsidies. Providing indoor comfort is a critical issue – the dwellers often don’t have proper means of heating during the cold winter period. Implementing solar energy might possibly be the solution to resolve this problem. This paper evaluates a design of a low-cost house that utilizes solar energy to provide indoor comfort. Evaluation is based on theoretical calculations, dynamic computer simulations, and on-site measurements and testing. The results show positive results. Theoretically the current design for a low-cost house working with solar technology functions sufficiently, even more so if the improvements recommended by this report will be implemented. It was found that factors having strong effect on system performance were: - the heat loss coefficient of the rockbed – installing heat insulation around the rockbed, thus reducing the heat loss coefficient from 11.35 kJ/hm2K to about 5 kJ/hm2K, the low values of indoor night temperatures can be increased from 14?C to about 18?C. - the flow rate of fluid circulating in the closed loop – by reducing the flowrate from 0.32 kg/s to 0.16 kg/s, the indoor temperatures during the night can be increased from 14?C to about 16.5?C. - by combining these improvements, a nighttime indoor temperature of about 22?C can be achieved. Further testing is required to confirm these presumptions, but until then this new, innovative design silution is deemed to be a successful trial in improving indoor comfort through utilizing solar technology.

  • 125.
    Kovács, Dániel Dávid
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Várnai, Balázs
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Passive Solar Design for Low Cost Housing in South Africa2005Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    South Africa is one of the many African countries, where housing situation needs urgent improvements. Although the government is willing to help, without foreign support problems are overwhelming. A number of studies were done to find solutions, partly by the Swedish International Development Cooperation Agency (SIDA) in cooperation with Karlstad, Kimberley and Borlänge. Aim is to start large scale housing projects that are not only simple and cost effective, but also utilize renewable energy sources effectively. This paper is a continuation of former studies on low cost housing in South Africa. Built upon existing research and improvements effort was made to further increase indoor temperature and comfort, sometimes taking different paths as compared to past years’. The complete project was a joint work of us (Dániel and Balázs) started by identifying problems and finding ways of improvements through discussing single details and writing the paper itself. Although it is a collective the report can be split into parts written by us respectively; chapters 3, 4. and 5. were done by Daniel and chapter 6. and 7. by Balázs. The results were positive, although further works are necessary to achieve completely pleasant indoor temperature both in winter and summer. Suggestions for possible future improvements are also given in the report. Most important achievements are: ? An attempt was made to eliminate all mechanic components from the system and thus reduce chance of malfunctions and maintenance problems. The solution was meant to eliminate electric components contributing a significant decrease of the overall price. ? Utilizing the solar chimney driven heating system indoor temperature could be increased with 0.7 centigrade in average, with 0.8 degrees at best winter conditions and with 0.5 centigrade at worst winter conditions. These values are based on daily average weather data and calculated with the mathematical model for the solar chimney driven heating system discussed in chapter 4. ? By improving wall insulation, decreasing infiltration heat loss through air leaks and designing a multi functional low cost shading device for the north facing windows, overall heat losses are reduced by 29 percent improving indoor comfort. ? Use of shading devices against overheating problems in hot summer days indoor temperature is reduced by a maximum of 1 oC. In winter aluminum foil of the shade reduces cooling of the house with 0.5 - 1.5 oC.

  • 126. Kovács, P.
    et al.
    Pettersson, U.
    Persson, M.
    Perers, Bengt
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Fischer, S.
    Improving the accuracy in performance prediction for new collector designs2011Conference paper (Refereed)
  • 127. Letz, T
    et al.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Perers, Bengt
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    A New Concept for Characterisation of Solar Combisystems: The Fsc Method2003In: Proceedings ISES 2003, Gothenburg, Sweden, 2003Conference paper (Other academic)
  • 128.
    Li, Hongwei
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Entrance Effect on Thermal Stratification of Solar Storage Tank2004Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    The hot water storage tank is the most important component in small SDHW systems concerning the system thermal performance. The build up of thermal stratification inside the storage tank has the advantages of improving energy quality of domestic hot water and of increasing the thermal efficiency on the collector side. The most effective way to preserve energy quality and avoid destratification is to avoid the cold water jets entering the tank during the discharge process. The factors influencing the degree of mixing during draw-offs are numerous. They were extensively investigated in different previous studies, based on both theoretical and experimental approaches. In this thesis, the inlet effect in a marketed solar storage tank (Metro tank) on thermal stratification is analyzed through theoretical approach. The storage tank model is generated and meshed by using the grid generation tool Gambit. The temperature and velocity field around the cold water inlet device are calculated with Computation Fluid Dynamic (CFD) simulation toolbox FLUENT. The simulation results are compared with the thermal experiment carried out in a pervious study, with temperature measurement of different levels inside the tank during and after a draw-off test. The purpose of this study is to generate a valid tank model and gather the information about the mixing effect, which is influenced by the inlet device geometry and operating conditions during and after the draw-off. A sensitive study is further carried out for different tank geometries, to reveal how the size of the tank diameter influences the flow structure and the mixing in the solar storage tank during hot water draw-offs.

  • 129.
    Lindberg, Eva
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Geometries for enhancing the output from PV cells1997Report (Other academic)
    Abstract [en]

    In a world of limited resources and increasing demand for energy sources, especially in developing countries, PV cells are of great interest. Despite fairly large efforts in certain countries, among them Sweden, in R&D of new technology, the cells are still expensive regarding cost per watt. Obviously there should be interest also in other solutions than increasing cell efficiency for enhancing the output from the PV systems. Some solutions could be different geometries of both the PV cells and the PV cells combined with concentrating equipment such as cones and cornets, lenses, or V-trough mirror concentrators. Geometries studied in this thesis are: square comets, linear Fresnel lenses, V-trough/Fresnel lens combinations, concave and convex cylindrical surfaces, and PV panels mounted an an adjustable rack. Square cornets with flat mirrors have even light distribution at the exit aperture, which is an advantage over circular cornets and CPC cones which have uneven light distribution and cause hot spots at the exit aperture. Measurements and calculations on silver coated and aluminum coated cornets indicated that arrangements with comets having a PV cell at the exit aperture are technically worthwhile. The concentration depends on the geometry of the comet and the reflector material of the surface. The low cost, compared to PV cells, of polished and coated 0.7 mm aluminum makes it probable that the use of cornet concentrators would reduce the cost per produced kWh. Factors to take into account are the higher labor and material costs for manufacturing modules with cornets. Direct sunlight can be concentrated by lenses. Since large ordinary lenses are too bulky, flat linear or circular Fresnellenses are the only practical lenses for solar energy applications. The Fresnel lens is however less perfect than ordinary lenses since not all incident rays hit facets. The linear Czech Fresnel lens is made of glass and mass-produced in an inexpensive and technically simple method, but the surface is not optically perfect due to a slight sagging of the rolled grooved surface during the hardening of the glass. The ray tracing results have therefore been supplemented with measurements. Both rays incident on the flat surface and on the grooved surface were studied, as well as normal incidence and various combinations of meridional and sagittal angles of incidence. The measurements show that focallength varies from 35 cm to 60 cm for focal band widths about 5 cm, depending on incidence angles and whether the flat or grooved surface faces the sun. This Fresnellens could be combined with a PV panel consisting of solar cells connected in series in one row, which is placed in the focal band. The Czech Fresnellens could also be combined with a V-trough mirror concentrator and with one row of PV cells or one long, thin-film PV cell at the bottom of the trough. A test bench has been constructed, and six different geometries have been studied: For all of these geometries four cases have been studied: troughs without the lens, with the flat surface of the lens and the grooved surface facing the sun, and the lens only with the mirrors covered. The concentration was measured by comparing the short circuit current from a PV cell at the bottom of the trough. The measurements indicated that the acceptance angle is larger when the grooved surface faces the sun than when the flat surface faces the sun, but the concentration is slightly larger when the flat surface faces the sun. For the investigated geometries the light concentration varies from 1.9 to 3.2. The reflection losses from a flat surface are large for high incidence angles. At high latitudes a substantial part of the sunlight hits the surface of a stationary PV panel at high incidence angles. In order to reduce the reflection losses one solution could be to produce thin-film PV panels with concave or convex surfaces. Calculations have been carried out for six different refractive indices of the surface and six different ratios between the depth of the curved surface and the width of the surface. For all these combinations the conditions for both one surface and two surfaces (panes) have been calculated. The results show that for transparent concave panes the overall reflection losses could be reduced by one to two percent units compared to a flat surface. The last idea investigated was the improvement of PV panel output by changing the panel azimuth thrice daily. Calculations were carried out for three different latitudes at locations in the north, the middle and the south of Sweden in order to estimate the most suitable azimuths and tilt angles for the three azimuth changes. The calculations show that the insolation could be increased by 38 %,30 %, and 28 %, respectively, as compared with a stationary panel. Measurements were carried out in Borlänge, the middle location. The voltage and current from two panels, one fixed at the best tilt and one turned thrice daily, were measured every sixth minute and stored using a data logger. For four days in July with normal weather the gain was 30 % compared to the stationary panel, and for seven days in August with sunny weather the gain was 39 %. If a simple and inexpensive adjustable mount could be manufactured, this idea would be very interesting in order to enhance the PV output for a small panel of a few modules to be used, for instance, at a summer cottage.

  • 130.
    Lindberg, Eva
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Rapport från 20th European Photovoltaic Solar Energy Conference and Exhibition: Barcelona 6-10 juni 20052005Report (Other academic)
    Abstract [sv]

    På uppdrag av STEM bevakade Eva Lindberg från Centrum för solenergi-forskning, SERC, Högskolan Dalarna, 20th European Photovoltaic Solar Energy Conference and Exhibition, Barcelona, 6-10 juni 2005. Ca 1700 personer fanns på deltagarlistan. På grund av konferensen omfattning kan endast ett litet urval av föredrag och utställare kommenteras i rapporten. Konferensprogrammet var indelat på följande områden: 1. Grundläggande fakta, nya komponenter och material 2. Kristallina kiselsolceller and materialteknologi 3. Amorft och mikrokristallint kisel 4. CIS, CdTe och andra (II-VI) ternära tunnfilmsceller 5. PV-moduler och komponenter i PV-system 6. PV-system i nätanslutna applikationer 7. Globala aspekter på PV-solelektricitet 8. PV-industrins resultat FoU om kristallina solceller dominerade stort, sedan tunnfilmsceller av främst amorft kisel. Intressant var att återvinning är föremål för FoU; dels återvinning av kiselsolceller när panelen tjänat ut; dels återvinning av Cu, Cd, Se och Te när tunnfilmscellerna tas ur bruk. 237 företag fanns representerade i utställningen, varav 20 från Kina. Tyskland dominerade stort. Utställningen teman var följande: 1) Tillverkare av kiselplattor, solceller, PV-moduler, koncentratorer, solföljare (se bild nedan) 2) Tillverkare och återförsäljare av utrustning och material 3) Integrering och distribution av system 4) Mätningar och kontrollteknologi 5) Forskning och laboratorier 6) Service, teknik, konsulting 7) Myndigheter och föreningar 8) Media och förlag 9) Tillverkare av inverterare 10) Övrigt.

  • 131.
    Lindberg, Eva
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Solar energy in Czechoslovakia1990Report (Other academic)
    Abstract [en]

    The purpose of my tour to Czechoslovakia was to participate the Third International Conference Applied Optics in Solar Energy, which was held in Prague, Octoher 2-6, 1989, and then visit some scientific institutes and solar collector plants as guest of the Czechoslovakian Academy of Science. This was made possihle hy an exchange researcher grant from the Royal Swedish Academy of Engineering Sciences.

  • 132.
    Lindberg, Eva
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Solar position diagram1990Report (Other academic)
    Abstract [en]

    Program SOLVEJ är ett användarvänligt program som visar solens vandring över himlavalvet vid upp till fem valfria datum och vid valfri ort. Programmet är utvecklat av två skäl. För det första, att demonstreras för en intresserad allmänhet som del av vandringsutställning om solenergi, vilken är initierad och utarbetad av SERC. För det andra, att användas av solenerglintressenter för att snabbt få en uppfattning om solinstrålningen på en ort vid olika tidpunkter på året. Indata till programmet ges från tangentbordet. Som svar på frågor skrivs för vilken ort diagrammet skall gälla, max fem datum, ortens latitud och longitud, som anges positiv i västlig riktning, samt tidszonen. Varje uppgift avslutas med tryck på tangenten ENTER. Programmet kommer nu att rita ett koordinatsystem på skärmen. Första axeln visar vädersträcken, norr, öster, söder, väster och norr, varje delstreck utgör 10 grader. För södra halvklotet byter norr och söder plats. Andra axeln visar höjden över horisonten i grader, 0 till 90 grader och 10 grader för varje delstreck. Efter några sekunder ritas diagrammet upp med solhöjden som funktion av väderstrecket och varje hel timme markerad. Se fig. 1-4. Slutligen frågas efter om diagrammet skall ritas ut på printer. SOLVEJ avbrytes med att trycka CTRL+BREAK. SOLVEJ är skrivet i Quick-BASIC (se App. 1) och leveras både som källkod och körklar version. Lämplig dator är IBM-kompatibel AT med EGA- eller VGA-skärmkort (ej Herkules Lämplig printer är IBM Proprinter eller liknande matrisskrivare, kopplad till LPT1 på kommunikationskortet. Till grund för beräkningarna har använts artikeln On Calculating the Position of the Sun, publicerad i nr. 1 1988 av The International Journal of Ambient Energy. Fem empiriska ekvationer beträffande beräkningar av solens position har studerats för att undersöka deras tillförlitlighet. Felaktigheter på fem grader eller mer kan uppträda om man använder sig av de enkla ekvationer som kan hittas solenergi-böcker och som inte kräver tillgång till dator. FORTRAN-rutinen SUNAE2 (se App. 2) beräknar solpositionen med noggrannast kända metod. Program SOLVEJ är en utveckling av SUNAE2.

  • 133.
    Lindberg, Eva
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Ten years experience of a 3 kW grid connected system with three different inverters2005In: Proceedings of the 20th European Photovoltaic Solar Energy Conference, Barcelona, 2005Conference paper (Other academic)
    Abstract [en]

    During 1994 a PV array of 72 modules à 45 Wp was installed at the roof the main buildning of Dalarna University, Borlange, Sweden. 32 of theses modules were connected to NEG 1600 inverter, and in 1996 the remaining 40 modules were connected to Solvex 2065. After some years the output of NEG 1600 decreased, and the whole system performance was investigated in detail as a student project. The fragile part was found to be the inverter, and when this inverter finally stop working it was replaced by NT 1800 in 2004. The performance of the three inverter systems are monitored and compared, losses and errors are analyzed and presented. The new inverter NT 1800 shows much superior performance as compared to the old Solvex inverter, an increase of 30% of the annual yield can be obtained. Studies show that inverter designs are improved significantly in recent years. Efficiency at partial loads have increased and more accurate MPPT algorithms are employed.

  • 134.
    Lindberg, Eva
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    TPV optics studies: on the use of non-imaging optics for improvement of edge filter performance in thermophotovoltaic applications2002Doctoral thesis, monograph (Other academic)
  • 135.
    Lindberg, Eva
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Broman, Lars
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    A computer study of the improvement of PV panel monthly outputs when the panel azimuth is changed thrice daily1994Report (Other academic)
    Abstract [en]

    The purpose of the calculations was to estimate the most suitable slopes and azimuths for three different positions per day of a solar panel in order to obtain the most possible energy from the PV panel compared with a stationary PV panel. The calculations were made in the computer program PV F-CHART.

  • 136.
    Lindberg, Eva
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Broman, Lars
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    An animation tool for demonstrating the importance of edge filters in thermophotovoltaic applications2002In: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 28, p. 1305-1315Article in journal (Refereed)
    Abstract [en]

    In order to achieve high efficiency in a thermophotovoltaic (TPV) generator, it is important that a high fraction of emitted photons with energies below the TPV cell bandgap are reflected back to the emitter. This can be accomplished in several ways, and one suggestion is to place an edge filter between the emitter and the TPV cell array in an elliptical optic design. An animation tool, developed in the Excel® program, for determining the efficiency of an optical system is presented. The animation components are a black body emitter, an edge filter, and an array of TPV cells. The tool has been used to demonstrate the importance of an efficient filter and the usefulness of optics that makes the edge of the filter as sharp as possible.

  • 137.
    Lindberg, Eva
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Broman, Lars
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    An animation tool for demonstrating the importance of edge filters in thermophotovoltaic applications2003In: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 28, p. 1305-1315Article in journal (Refereed)
    Abstract [en]

    In order to achieve high efficiency in a thermophotovoltaic (TPV) generator, it is important that a high fraction of emitted photons with energies below the TPV cell band gap are reflected back to the emitter. This can be accomplished in several ways, and one suggestion is to place an edge filter between the emitter and the TPV cell array in an elliptical optic design. An animation tool, developed in the Excel program, for determining the efficiency of an optical system is presented. The animation components are a black body emitter, an edge filter, and an array of TPV cells. The tool has been used to demonstrate the importance of an efficient filter and the usefulness of optics that makes the edge of the filter as sharp as possible. It is available at www.du.se/tpv.

  • 138.
    Lindberg, Eva
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Broman, Lars
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Edge filters in thermophotovoltaic applications2001In: 17th European Photovoltaic Solar Energy Conference, München, Tyskland, 2001Conference paper (Refereed)
    Abstract [en]

    In order to achieve high efficiency in a TPV generator, it is important that a high fraction of emitted photons with energies below the TPV cell bandgap are reflected back to the emitter. This can be accomplished in several ways. We present the idea of an internally reflecting egg-shaped double cone with emitter at one end, an edge filter at the wide center, and the TPV array at the other end. This geometry has so far been studied by means of both ray tracing analysis and by means of measurements with a simulated emitter. A sharp switchover from transmission to reflection in a multiple layer dielectric filter can be achieved only if the angles of the incident rays are confined to a fairly narrow interval. The two methods both show thet the studied optics can lower the angular spread of rays incident onto the filter and that some 96% of the emitted rays (in the ideal case) reach their goal without passing the filter more than once.

  • 139.
    Lindberg, Eva
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Broman, Lars
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Fabergé optics and edge filter for a wood powder fuelled thermophotovoltaic system2002In: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 28, p. 373-384Article in journal (Refereed)
    Abstract [en]

    In order to achieve high efficiency in a TPV generator, it is important that a high fraction of emitted photons with energies below the TPV cell bandgap are reflected back to the emitter. This can be accomplished in several ways. We present the idea of an internally reflecting eggshaped double cone with the emitter at one end, an edge filter at the wide center, and the TPV array at the other end. This geometry has so far been studied by means of both ray tracing analysis and by means of measurements with a simulated emitter. A sharp switchover from transmission to reflection in a multiple layer dielectric filter can be achieved only if the angles of incident rays are confined to a fairly narrow angular interval. The two methods both show that the studied optics can lower the angular spread of rays incident onto the filter and that some 96% of the emitted rays (in the ideal case) reach their goal without passing the filter or being reflected by the filter more than once. The concept of the whole of the wood powder fuelled TPV system is also given.

  • 140.
    Lindberg, Eva
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Broman, Lars
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Non-imaging optics in a thermophotovoltaic generator2002In: Fifth Conference on Thermophotovoltaic Generation of Electricity, Rome, Italy, 2002Conference paper (Other academic)
    Abstract [en]

    In order to achieve high efficiency in a TPV Generator, it is important that a high fraction of emitted photons with energies below the TPV cell bandgap are reflected back to the emitter. this can be accomplished in several ways. We present the idea of an internally reflecting egg-shaped double cone with the emitter at one end, an edge filter at the wide center, and the TPV array at the other end. So far, we have studied this geometry by means of both ray tracing analysis in a computer program and by means of measurements with an emulated emitter. A sharp switchover from transmission to reflection in a multiple layer edge filter can ba achieved only if the angles of incident rays are confined to a fairly narrow angular interval. The two used methods both show that the studied optics can lower the angular spread of rays incident to the filter and that some 96% of the emitted rays (in the ideal case) reach their goal without passing the filter or being reflected by the filter more than once. A suggestion of a whole wood powder fuelled TPV system with this egg-shaped double cone and edge filter implemented is also given, as well as an animation tool for modelling the optical part of the system.

  • 141.
    Lindberg, Eva
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Broman, Lars
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    ESES, A European Master's Program In Solar Energy Engineering2004In: Eurosun 2004, Freiuburg, Germany, 2004Conference paper (Other academic)
    Abstract [en]

    The first group of students was admitted to the European Solar Engineering School, a master’s level two-semester program at Dalarna University in Sweden, in August 1999. Now that the fifth group is all but through their year, some conclusions from our experiences are possible to draw. The paper gives the background of ESES, some information about how the program is arranged, and also some of the ESES staff experiences.

  • 142.
    Lindberg, Eva
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Kraus, Alex
    Broman, Lars
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Animation tool and Q. E. measurements for estimating the optimum system efficiency of a TPV generator2004In: Sixth Conference on Thermophotovoltaic Generation of Electricity, Freiburg, Tyskland, 2004Conference paper (Other academic)
    Abstract [en]

    In order to achieve high efficiency in a thermophotovoltaic (TPV) generator, it is important that a high fraction of emitted photons with energies below the TPV cell band gap are reflected back to the emitter. This can be accomplished in several ways, and one possibility is to place an edge filter between the emitter and the TPV cell array in an elliptical optic design. By this arrangement the cooling demand on the TPV cells is reduced and the reflected radiation is reused in the emitter, the fuel demand is decreased. An animation tool, developed in the Excel program, for determining the optical availability in such a system has been presented previously. The animation components were a blackbody emitter, an adjustable edge filter, and an array of TPV cells. The tool was used to demonstrate the importance of an efficient filter and the usefulness of optics that makes the edge of the filter as sharp as possible. In such a system the TPV cells are the dominant cost. It is possible to tailor the selective filter in order to fit the bandgap of a certain TPV cell. For this purpose it is a great advantage to be able to measure the Quantum Efficiency Q.E. of the cell and how Q.E. changes at different temperatures. When this behaviour is known it is possible to tailor the selective edge filter in order to get higher efficiency. A simple measurement setup has been developed utilizing a lamp with IR reflector, a monochromator, a radiometer, and a heating system based on hot water. The animation tool has been further developed for estimating the optical efficiency, and more factors may be varied. The tool can now handle also the emittance of the emitter, absorption losses in mirrors and filter, as well as TPV cell characteristics such as adjustable Q.E., fill factor FF, and Uoc/(Eg/q).

  • 143.
    Lorenz, Klaus
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Bygg själv din solvärmeanläggning1996Book (Other academic)
  • 144.
    Lorenz, Klaus
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Kombisolvärmesystem: Utvärdering av möjliga systemförbättringar2001Licentiate thesis, monograph (Other academic)
  • 145.
    Lorenz, Klaus
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Rapport från/Report from IEA Task-14 mötet/meeting on solar heating system, Hameln Tyskland/Germany August 19921993Report (Other academic)
    Abstract [en]

    Participation as observer at the meeting of Task 14 of IEA's Solar Heating and Cooling Projects held in Hameln, Germany has led to greater understanding of interesting developments underway in several countries. This will be of use during the development of small scale systems suitable for Swedish conditions. A summary of the work carried out by the working groups within Task 14 is given, with emphasis on the Domestic Hot Water group. Experiences of low-flow systems from several countries are related, and the conclusion is drawn that the maximum theoretical possible increase in performance of 20% has not been achieved due to poor heat exchangers and poor stratification in the storage tanks. Positive developments in connecting tubes and pumps is noted. Further participation as observer in Task 14 meetings is desired, and is looked on favourably by the members of the group. Another conclusion is that SERC should carry on with work on Swedish storage tanks, with emphasis on better stratification and heat exchangers, and possible modelling of system components. Finally a German Do-it-Vourself kit is described and judged in comparison with prefabricated models and Swedish Do-it-Yourself kits.

  • 146.
    Lorenz, Klaus
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Report on IEA Task-14 activities on solar collector systems conference in Rome, 25-29 Jan. 19931993Report (Other academic)
    Abstract [en]

    The memebers of IEA (International Energy Agency) Task 14 (Advaced Active Solar Systems) met in Rome during January 1993. The latest developments in several countries were presented and discussed during this meeting. This report describes briefly the recent work carried out on small scale systems in the Domestic Hot Water (DHW) working group of Task 14, as reported by the representatives from Canada, Denmark, Germany, Holland and Switzerland. Klaus Lorenz, SERC, attended the meeting as observer and presented our work on small-tube heat exchangers. Several participants expressed their interest. A summary of his presentation is included in this report.

  • 147.
    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.
    Pellet Integral - Auxiliary Pellet Burner Integrated into Solar Stores2003In: Proceedings ISES 2003, Gothenburg, Sweden, 2003Conference paper (Other academic)
  • 148.
    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.
    Broman, Lars
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Performance comparison of combitanks using six-day test1997In: North Sun'97, Helsingfors, Finland, 1997Conference paper (Other academic)
    Abstract [en]

    This paper compares the performance of configurations of solar heating combitank systems, which are designed to provide both space heating and domestic hot water (DHW), using a specially designed six-day test. The test sequence is applied to every tank with the same boundary conditions, so that the results, in the form of solar fraction, can be used for direct comparisons. The six days of radiation data were chosen after an analysis of the summer insolation data for Borlänge, Sweden, and are representative for the summer period in Sweden. The systems are tested with a purely DHW load with no space heating load. The solar collector is emulated using a collector hardware simulator (CHS). Sixteen combitank systems have been tested with the resulting solar fraction from the six-days ranging from 52% to 93%. This paper describes the test procedure, the tested systems, the results from the test and gives conclusions that can be drawn from a detailed analysis of the measured data.

  • 149.
    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.
    Börjesson, Kent
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Provning av ackumulatorsystem för solvärmeanläggningar1995Report (Other academic)
    Abstract [sv]

    Inom projektet provades 10 konfigurationer av samma ackumulatortank. Tankarna utsattes under kontrollerade förhållanden för en 6-dagars testcykel. Under testet tillfördes varje tank värme från en (simulerad) solfångare och, i den mån det behövdes, tillsatsvärme från elpatronen. Väderförhållanden under de sex dagarna var två fina, en växlande, två dåliga och ytterligare en växlande dag i nämnd följd. De flesta systemkonfigurationer klarade sig under de soliga dagarna utan energitillskott från elpatronen och förmådde dessutom att lagra värnlen så att även tappningar på följande dag med "växlande" väder kunde ske utan el-tillskott. De molniga dagarna behövde alla systemkonfigurationer el-tillskott. Solvärmesystemens täckningsgrad varierade mellan 36,5 % för det sämsta systemet till 70, 3 % för det bästa. En ackumulatortank med två seriekopplade tappvarmvattenvärmeväxIare (en i botten för förvärmning och en i tankens övre del för slutvärmning) ger betydligt bättre resultat än en tank med bara en enda sådan värmeväxlare. Tankens volym var i de utförda provningarna 750 liter, solfångarstorleken 10 m2 och lasten 13 kWh per dag. För dessa förutsättningar ger en yttre solvärmeväxlare inga mätbara fördelar gentemot en tillräcklig stor inbyggd värmeväxlare. De gjorda försöken visar, att alla tankkonfigurationerna visar dålig skiktning. Ett fortsatt arbete bör göras för att minska omblandningen i tanken vid både inladdning och uttag av värme.

  • 150.
    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.
    Börjesson, Kent
    Broman, Lars
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Villasystem för solvärme1993Report (Other academic)
    Abstract [sv]

    Del 1: Innehållsförteckning och korta sammanfattningar DEL 2: Verksamhetsberättelsen för perioden maj 1992 till april 1993 beskriver de arbeten som har gjorts av villasolvärmegruppen på SERC efter den inledande studie (SERC/UCFB-91/0039), där villasolvärmesystem kartlades. Följande arbeten beskrivs: - Utveckling av lågflödessystem och internationella kontakter - Uppbyggnad av värmelaboratorium på SERC - Praktiska test av värmelagringsenheten - Praktiska test av nya systemkomponenter i solvärmekretsen - Datasimulering inkluderande nyutvecklade systemkomponenter I verksamhetsplanen beskrivs huvudmålet för de arbeten som ska utföras under trårsperioden 93 - 96. Mera detaljerat beskrivs de arbeten som ska utföras under budgetåret 1993/94: - Beräkningsprogram för nogrannare dimensionering av finrörsvärmeväxlare - Konstruktion av maskiner för värmeväxlartillverkning - Utveckling av värmeväxlare för tappvarmvatten - Simuleringsberäkningar för hela systemet med PRESIM/TRNSYS. DEL 3: Del 3 innehåller en redovisning av mätresultat för den undersökta kombitanken. Temperaturförloppen på olika höjd i tankens har studerats vid uppvärmning genom solvärmeväxlaren och nedkylning genom tappning av varmvatten. Resultaten diskuteras kvalitativt och redovisas kvantitativt i form av diagram. Mätresultaten på två prototyper av den på SERC utvecklade finrörsvärmeväxlaren redovisas och diskuteras i jämförelse till traditionell värmeväxlare. De erhållna mätresultaten används som ingångsvärden för simuleringsberäkningar med PRESIM/TRNSYS. Problemen med de i PRESIM/TRNSYS befintliga modellerna diskuteras. De utförda modellberäkningarna tillåter en uppskattning av möjliga förbättringar i form av höjd årsverkningsgrad för ett svenskt villasolvärmesystem med kombitank. I del 3 redovisas dessutom de mätningar som har utförts på otika pumpar vilka skulle kunna användas i solfångarkretsen. Sex olika pumpar analyseras och diskuteras. Del 3 har följande rubriker: - Beskrivning av den undersökta lagringstanken - Mätningar på tappvarmvattenväxlare - Mätningar på solvärmeväxlare (kamflänsrör och finrörsvärmeväxlare) - Simuleringsberäkningar - Pumpmätningar DEL 4: Del 4 innehåller publicerade rapporter under 1992 och 93 samt patentansökan för SERC?s finrörsvärmeväxlare: - NORTH SUN 1992, Solar Energy at High Latitudes, June 24-26 1992 Trondheim, Norway. Domestic solar heating system - a systematic study i progress Patentansökan på finrorsvärmeväxlare till Patent- och Registreringsverket från 93 01 23. ISES SOLAR WORLD CONGRESS, 23-27 augusti 1993, Budapest, HUNGARY Criteria for cost efficient small scale solar hot water installations. DEL 5: Del 5 hänvisar till rapporterna från IEA Task-1 4 mötena om solfångarsystem i - Hameln, Tyskland, augusti 1992 och - Rom, Italien, januari 1993. I rapporterna beskrivs aktiviteten inom den internationella arbetsgruppen speciellt med hänsyn på utveckling av villasolvärmesystem. I Rom presenterades principlösningen för den på SERC utvecklade finrörsvärmeväxlare. De har publicerats separat som nr 42 och 46 i SERCs rapportserie.

123456 101 - 150 of 292
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • chicago-author-date
  • chicago-note-bibliography
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf