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  • 1. Beckert, Rolf
    et al.
    Broman, Lars
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Jarefors, Kenneth
    Bücher, Klaus
    Measurement comparison of InGaAs- and GaSb-based (thermo-)photovoltaic cells with two different methods1998In: Second World Conference on Photovoltaic Solar Energy Conversion, Wien, Österrike, 1998Conference paper (Refereed)
    Abstract [en]

    The aim of this investigation is to show, whether totally different calibration methods (absolute spectral response at Fraunhofer ISE, blackbody at various temperatures at SERC) give similar results for the performance of TPV cells under infrared spectra. Two cell types (InGaAs and GaSb) have been tested, applying two different methods to each cell type. Spectral responses and I-V-curves of the cells have been measured. To compare the two methods the spectra of a halogen light bulb were measured up to 1.6 µm at different lamp currents and then fitted to the Planck formula and in this way extended into the infrared. The two methods are compared to each other and results are discussed. It is shown that the I-V-curves of both cell types are independent of the used spectrum. The currents of the cells measured at SERC and calculated at Fraunhofer ISE differ only in the range of measurement errors.

  • 2. Beckman, William A
    et al.
    Broman, Lars
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Fiksel, Alex
    Klein, Sanford A
    Lindberg, Eva
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Schuler, Mattias
    TRNSYS, the most complete solar energy system modeling and simulation software1994In: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 5, no 1-4, p. 486-488Article in journal (Refereed)
    Abstract [en]

    The five computer programs TRNSYS, PRESIM, TRNSED, ONLINE, and PREBID have been put together into a program package which is the most complete solar energy system modeling and simulation software that is available today.

  • 3. Broman, Arne
    et al.
    Broman, Lars
    Dalarna University, School of Languages and Media Studies, Science communication.
    Museum exhibits for the conics1994In: Mathematics Magazine, ISSN 0025-570X, E-ISSN 1930-0980, Vol. 67, no 3, p. 206-209Article in journal (Refereed)
    Abstract [en]

    It is rather common nowadays that museums, especially those of the "science center" type, have showcases where visitors can perform experiments. In the Futures' Museum in Borlänge we have made an exhibit where interested persons can construct parabolas. In this note we describe this showcase. Analogous exhibits can be made for constructing ellipses and hyperbolas.

  • 4.
    Broman, Lars
    Dalarna University, School of Languages and Media Studies, Science communication.
    Kommunicera vetenskap och extramuralt lärande2004In: Naturfagenes didaktikk - en disiplin i forandring / [ed] Henriksen, Ellen K; Ødegaard, Marianne, Kristiansand: Norwegian Academic Press , 2004, p. 503-516Chapter in book (Other academic)
    Abstract [sv]

    Vetenskapscentret och planetariet är institutioner som utgår ifrån situationer till skillnad museet som utgår från föremål. Deras didaktik präglas av extramuralt lärande, interaktivitet och upplevelser. Många av dagens vetenskapscentra har som främsta målgrupp "7-Eleven" (barn mellan 7 och 11 år), och vill göra gruppen både mer intresserad av och mer kunnig i naturvetenskap och teknik. Vid Högskolan Dalarna finns en enterminskurs, Kommunicera vetenskap. Delvis inom ramen för denna har ett antal mindre studier gjorts, framför allt syftande till att undersöka i vad mån vetenskapscentra och planetarier lyckas leva upp till sina målsättningar. Studierna tyder på att det inte finns ett enhetligt resultat. Vi startar hösten 2003 en 50 veckors breddmagisterkurs i Vetenskapskommunikation. Vi avser att involvera magistrander i fortsatt forskning om extramuralt lärande.

  • 5.
    Broman, Lars
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    On reflection losses from cylindrical PV modules1989In: Solar Cells, ISSN 0379-6787, Vol. 27, p. 489-500Article in journal (Refereed)
  • 6.
    Broman, Lars
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    On the possibility of space generated solar electricity for the Antarctic1991In: Space Power, ISSN 0883-6272, Vol. 10, no 1, p. 19-20Article in journal (Refereed)
    Abstract [en]

    A space based solar power plant could be placed in a geostationary orbit 36000 km above the earth's equator. A receiving station must be north of 81.3 degrees latitude south for the satellite to be above horizon. Large areas of the Antarctic are substantially above this latitude. Since such a solution would be much more environmentally benign than land-based fossil or nuclear fuel power plants, it is proposed that the first space power plant is built for this specific purpose.

  • 7.
    Broman, Lars
    Dalarna University, School of Languages and Media Studies, Science communication.
    Science in informal education1996In: Fifth Nordic Research Symposium on Didactics of Science, 1996Conference paper (Other academic)
    Abstract [en]

    The course Popular Science with Emphasis on the Didactics of Science Centers (5 cr. + 5 cr. extension) is held at Dalarna University College for the first time during the academic year 1995/96. In the present paper, basic thoughts and ideas as well as the curricula are presented. Also, some of the struggle (in Sweden and abroad) to modernize the pedagogics at science centers and museums- including "the constructivist museum" is discussed. Finally, the plans of regional networks of local science centers will be mentioned.

  • 8.
    Broman, Lars
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Solar energy at northern latitudes1997In: North Sun'97, 1997Conference paper (Other academic)
    Abstract [en]

    A joint project between SERC, SLU and National Renewable Energy Laboratory NREL in Golden, Colorado, USA aims at building a wood powder fuelled TPV generator. An emitter temperature around 1500 K is required. There are some different biomass fuels capable of producing this temperature in the flame, including wood powder, the only sufficiently uniform solid wood fuel. A stable flame temperature of 1500 K has been achieved in a prototype pilot-scale burner that includes feeder and combustion chamber. Furthermore, a setup for measuring TPV cell efficiency for a wide region of black body emitter temperatures and cell irradiation has been constructed and several 0.6 eV GaInAs TPV cells have been investigated. A setup for testing the chain IR emitter - selectively reflecting filter - TPV cell has been designed. In order to limit the region of filter incident angles - which will make the filter act more efficiently - a special geometry of the internally reflecting tube that transmits the radiation is considered.

  • 9.
    Broman, Lars
    Dalarna University, School of Languages and Media Studies, Science communication.
    Solar energy exhibits at the popular science park Teknoland2000In: 7th International Symposium on Renewable Energy Education, Oslo, Norge, 2000Conference paper (Other academic)
    Abstract [en]

    The new Popular Science Park TEKNOLAND in Falun contains a number of interactive solar energy exhibits, including The Solar Heated Chess Board, The Solar Electric Playhouse, The Sudanese Solar Oven, and Solar Collector Optics. The TeknoTrix tutored children activities include solar thermal activities. Some related interactive exhibits are planned to be included during the summer and during coming years.

  • 10.
    Broman, Lars
    Dalarna University, School of Languages and Media Studies, Science communication.
    Solar energy studies and extramural learning2003In: ISES Solar World Congress, 2003Conference paper (Refereed)
    Abstract [en]

    Extramural learning refers to the educational process that takes place outside the walls of the school (or the university). Extramural learning that takes place in a science center is characterized by hands-on and interactivity. Interactive solar energy exhibits are particularly well suited for out-door science centers. The paper presents some solar energy hands-on exhibits and extramural activities that the author has initiated and participated in.

  • 11.
    Broman, Lars
    Dalarna University, School of Languages and Media Studies, Science communication.
    Teknoland - popular science park with solar energy exhibits2000In: EuroSun 2000, Köpenhamn, Danmark, 2000Conference paper (Other academic)
    Abstract [en]

    The new Popular Science Park TEKNOLAND in Falun contains a number of interactive solar energy exhibits, including The Solar Heated Chess Board, The Solar Electric Playhouse, The Sudanese Solar Oven, and Solar Collector Optics. The TeknoTrix tutored children activities include solar thermal activities. Some related interactive exhibits are planned to be included during the summer and during coming years.

  • 12.
    Broman, Lars
    Dalarna University, School of Languages and Media Studies, Science communication.
    The Boundless Planetarium Proceedings: IPS'90, Galaxen, Borlänge 15-19 juli 19901990Book (Other academic)
    Abstract [en]

    These Proceedings include 65 papers, grouped under the following headings: The international planetarium scene. International Planetarium Society Committee Reports. Astronomy for the planetarium. Cosmos and space in the planetarium. Didactics for the planetarium. Outside the big dome. Planetarium techniques. Planetarium management and co-operation.

  • 13.
    Broman, Lars
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Thermophotovoltaics bibliography1995In: Progress in Photovoltaics, ISSN 1062-7995, E-ISSN 1099-159X, Vol. 3, no 1, p. 65-74Article in journal (Refereed)
    Abstract [en]

    A bibliography containing 200 entries on thermophotovoltaic conversion of energy between 1960 and 1995 has been compiled. The entries are categorized with respect to type and contents.

  • 14.
    Broman, Lars
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Årsredogörelse för 18 månader 1995/96 Ekologi och samhälle EKOS för FOU-verksamhet inom forskningsenheten1997Report (Other academic)
  • 15.
    Broman, Lars
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Lindberg, Eva
    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.
    Rapport ramprogram FOU 1993-96, Projektnr 930391-05 samt förslag till ramprogram solfångarutveckling och systemteknik FOU 1997-99 solfångarutveckling och systemteknik1997Report (Other academic)
  • 16.
    Broman, Lars
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Broman, Arne
    Parabolic dish concentrators approximated by simple surfaces1996In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 57, no 4, p. 317-321Article in journal (Refereed)
    Abstract [en]

    Two different concentrating mirrors have been constructed that resemble parabolic dish reflectors. Both mirrors are made of slightly curved strips of flat, bendable material. The strips of the most simplified mirror have only large-radius circles and straight lines as boundaries. The necessary equations for making the mirrors are given. Also a simple way to make a stiff, lightweight frame and support for the mirror strips has been developed. Models of the mirrors have been built and successfully used for cooking and baking.

  • 17.
    Broman, Lars
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Broman, Arne
    Nordlander, Svante
    Rönnelid, Mats
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Analysis of four different solar corner concentrators1987In: Applied Optics in Solar Energy, Prague, Czechoslovakia, 1987Conference paper (Other academic)
  • 18.
    Broman, Lars
    et al.
    Dalarna University, School of Languages and Media Studies, Science communication.
    Broman, Per
    Dalarna University, School of Languages and Media Studies, Science communication.
    Astronomical interactive exhibits2002In: 16th International Planetarium Society Conference, Wichita, KA, USA, 2002Conference paper (Other academic)
    Abstract [en]

    It has been shown (Franck Pettersen, Master thesis 1995) that a planetarium show has a much larger educational impact if it is accompanied by hands-on experimenting. In the present paper, a number of interactive exhibits that we have used together with Stella Nova Planetarium at Falun Science Center and at Teknoland are presented.

  • 19.
    Broman, Lars
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Datta, Gouri
    Solar collector geometries at high latitudes1991In: ISES Solar World Congress, Denver, CO, USA, 1991Conference paper (Refereed)
    Abstract [en]

    Insolation onto and energy output from solar collectors have been estimated for some typical high latitude locations using the F-Chart computer program and weather data from the Swedish Meteorological and Hydrological Institute. Optimum tilt for south-facing collectors at Swedish latitudes is approximately latitude minus 20 degrees for maximum yearly performance, and about latitude minus 30 degrees for maximum summer performance. If tracking is considered, vertical axis tracking seems favorable with energy gain larger than normal 1-axis tracking with latitude tilted axis.

  • 20.
    Broman, Lars
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Eriksson, Göran
    Solar energy in asia, in Kobe, Japan, september 1989: Reports from ISES solar world congress and from study visits in India and Pakistan1990Report (Other academic)
    Abstract [en]

    The ISES Solar World Congress Clean and Safe Energy Forever was held in Kobe, Japan, September 4-8, 1989. Short impressions from the conference and the simultaneous exhibition are given. On our (separate) ways to Kobe, Eriksson visited institutions in the Bombay, India area, and Broman one institution in Islamabad, Pakistan. Accounts of these visits are given. Three papers presented in Kobe are included in an Appendix.

  • 21.
    Broman, Lars
    et al.
    Dalarna University, School of Languages and Media Studies, Science communication.
    Gustafsson, Kjell
    A low-cost versatile solar hot water system for school laboratory work1997In: North Sun'97, Helsingfors, Finland, 1997Conference paper (Other academic)
    Abstract [en]

    A versatile low-cost solar hot water collector for school laboratory work has been constructed. It consists of a 4 dm2 absorber connected to an 80 cc storage tank. It is a complete system that works by means of thermosiphon convection of the water. A number of experiments and observations for students from kindergarden to college level are proposed.

  • 22.
    Broman, Lars
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Jarefors, Kenneth
    Lindberg, Eva
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Marks, Jörgen
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Square cones for TPV: experiments and computer simulations1998In: Fourth NREL Conference on Thermophotovoltaic Generation of Electricity, Denver, CO, USA, 1998Conference paper (Other academic)
    Abstract [en]

    The efficiency of a TPV generator is very dependent on selective optical properties of the chain emitter-filter-TPV cell-reflective backing. If a selective reflective edge filter using multiple reflections in dielectric layers is employed, the slope of the edge depends on the incidence angle interval. A special geometry, consisting of a double square cone between the (square) emitter and the (square) cell array, which narrows this angle interval significantly, has been constructed and investigated experimentally as well as with ray tracing analysis.

  • 23.
    Broman, Lars
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Jarefors, Kenneth
    Marks, Jörgen
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Electricity from wood powder: Report on a TPV generator in progress1995In: Second NREL Conference on Thermophotovoltaic Generation of Electricity, Colorado Srings, CO, USA, 1995Conference paper (Other academic)
    Abstract [en]

    A joint project between NREL, SLU and UCFB aims at building a wood powder fueled TPV generator. The progress of the project is presented.

  • 24.
    Broman, Lars
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Jarefors, Kenneth
    Marks, Jörgen
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Lindberg, Eva
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Enhancing the optical efficiency of a thermophotovoltaic generator using square cones in combination with interference filters1998In: Second World Conference on Photovoltaic Solar Energy Conversion, Wien, Österrike, 1998Conference paper (Refereed)
    Abstract [en]

    The optical efficiency is a week link in all TPV systems. Many different approaches have been studied earlier, but not much on the possibility to use interference filters. Such filters can be designed to get alsmost any desired optical performance, as long as it is allowed to use a large number of layers in the multilayer stack. In practical applications this is very often not acceptable. Nevertheless such filters can still be quite good, at least for a very narrow range of incident angles. Therefore a double-cone geometry is proposed to be used in combination with such filters. This geometry will limit the range of incident angles onto the filter, which will then act more efficiently. The influence of the geometry is evaluated by means of model experiments, and a computer program has been constructed to be able to simulate this type of geometry using ray-tracing technique.

  • 25.
    Broman, Lars
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Jarefors, Kenneth
    Marks, Jörgen
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Wanlass, Mark
    Efficiency measurements of TPV cells1997In: Third NREL Conference on Thermophotovoltaic Generation of Electricity, Colorado Springs, CO, USA, 1997Conference paper (Other academic)
    Abstract [en]

    An apparatus for measuring TPV cell efficiencies at different radiation intensities and for different graybody emitter temperatures has been constructed. The apparatus has been used for measuring V-I characteristics, efficiencies and fill factors for several InGaAs TPV cells. Measured results are used to determine how cells may function together with edge filters, and those results are compared with theory.

  • 26.
    Broman, Lars
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Lindberg, Eva
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Börjesson, Kent
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Optical properties of the Czechoslovakian Fresnel lens measured using a laser beam1989In: ISES Solar World Congress, Kobe, Japan, 1989Conference paper (Refereed)
    Abstract [en]

    Linear glass Fresnel lenses have been experimentally investigated by means of a narrow He-Ne laser beam, both at normal incidence and at various combinations of meridional and sagittal angles of incidence. Both rays incident on the flat and on the grooved side were studied. Results were compared with previous ray tracing results by Franc et al. The experiments suggest, contrary to ray tracing, that the grooves should face the sun in other than sun-tracking applications.

  • 27.
    Broman, Lars
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Marks, Jörgen
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Co-generation of electricity and heat from combustion of wood powder utilizing thermophotovoltaic conversion1994In: First NREL Conference on Thermophotovoltaic Generation of Electricity, Copper Mountain, CO, USA, 1994Conference paper (Other academic)
    Abstract [en]

    The development of a thermophotovoltaic converter that uses combustion of wood powder as energy source has started with development of the combustion source. During the last few months, we have constructed and tested a feeding mechanism and a combustion chamber that seem very promising. We manage to keep a 10 kW flame steadily burning for several minutes at the time, generating a temperature exceeding 1400 K. The plans for continued development of this and other components of the converter are discussed in the paper.

  • 28.
    Broman, Lars
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Marks, Jörgen
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Development of a TPV converter for co-generation of electricity and heat from combustion of wood powder1994In: First World Conference on Photovoltaic Energy Conversion, Hawaii, USA, 1994Conference paper (Refereed)
    Abstract [en]

    Wood fuel has a high energy density, 18.3 MJ/kg dry matter, and it is combustible also in existing oil furnaces (in the range 1-15 MW) with little alteration. In principle, wood powder would be a possible fuel for small scale combustion, and we are in the process of developing such a furnace. During the last few months, we have constructed and tested a feeding mechanism and a combustion chamber that seem very promising. As of November 1994, we have reached 1481 K and been able to keep the temperature around 1400 K for any length of time at the time in one of our two prototype burners. A joint TPV R&D program, in which we cooperate with researchers at National Renewable Energy Laboratory, Golden, CO, USA, is in the planning, aiming at co-generation of electricity and heat from refined wood fuel.

  • 29.
    Broman, Lars
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Marks, Jörgen
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    TPV at RNEL - Report from a visit to National Renewable energy lab. Golden, Colorado, USA 28-29 Oct. 19931993Report (Other academic)
  • 30.
    Broman, Lars
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Rönnelid, MatsDalarna University, School of Technology and Business Studies, Environmental Engineering.
    Proceedings of International Conference North Sun '881999Book (Other academic)
  • 31.
    Broman, Lars
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Rönnelid, Mats
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Binder, Betty
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Lindberg, Eva
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Use of nonimaging concentrators for moderate concentration of sunlight onto PV cells1989In: 9thy European Photovoltaics Solar Energy Conference, Freiburg, Tyskland, 1989Conference paper (Refereed)
    Abstract [en]

    The square cornet type nonimaging concentrator has been shown useful for moderate concentration of sunlight onto photovoltaic solar cells, since it creates no hot spots at the exit aperture. In this paper are presented the mathematical formulas on which the cornet designs are based, results from computer simulations on overall cornet performance compared with measurements as well as exit aperture intensity variations, measured optical concentration ratios under controlled circumstances, and cell temperature measurements under realistic circumstances. In an Appendix are given performance curves for a large number of cornets as determined from computer simulations, covering the useful range of concentration factors and acceptance angles.

  • 32.
    Broman, Lars
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Rönnelid, Mats
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Karlsson, Björn
    Bergkvist, Mikael
    Wäckelgård, Eva
    Use of an integrating sphere for transmittance measurements on nonimaging concentrators1989In: North Sun´88, Borlänge, 1989Conference paper (Other academic)
  • 33.
    Broman, Lars
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Rönnelid, Mats
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Nordlander, Svante
    Analysis of a possible perfect nonimaging concentrator1986In: North Sun´86, Copenhagen, Denmark, 1986Conference paper (Other academic)
  • 34.
    Broman, Lars
    et al.
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Rönnelid, Mats
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Sallah, S.O.A.
    On the role of solar electricity in rural development1987In: ISES Solar World Congress, Hamburg, 1987Conference paper (Other academic)
  • 35.
    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.

  • 36.
    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.

  • 37.
    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.

  • 38.
    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.

  • 39.
    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.

  • 40.
    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.

  • 41.
    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.

  • 42.
    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).

  • 43.
    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.

  • 44.
    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.

  • 45.
    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)
  • 46. 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)
  • 47. 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)
  • 48. 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)
  • 49.
    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.

  • 50. Schubnell, Markus
    et al.
    Gabler, Hansjörg
    Broman, Lars
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Overview of European activities in thermophotovoltaics1997In: Third NREL Conference on Thermophotovoltaic Generation of Electricity, Colorado Springs, CO, USA, 1997Conference paper (Other academic)
    Abstract [en]

    In Europe several research institutes and private companies are currently working or have been working in thermophotovoltaics. At the Solar Energy Research Center SERC in Sweden, the possibility of using wood as a fuel for a TPV-system emphasizing the aspect of co-generation of heat and electricity is investigated. SERC also does work on characterization on TPV cells and on TPV generator optics. The Fraunhofer Institute for Solar Energy Systems in Germany plans to develop a TPV-generator to assure the supply reliability for small off grid photovoltaic systems and in Switzerland the research foundation of the Swiss gas industry has approved a project proposed by the Paul Scherrer Institute to develop a residential TPV-gas-burner for co-generation of heat and electricity. We also report on activities in the United Kingdom as well as on a past research program in the Netherlands.

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