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| 5. |
- Perers, Bengt, et al.
(författare)
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Solceller 1996
- 1996
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Rapport (övrigt vetenskapligt/konstnärligt)
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- Rönnelid, Mats, et al.
(författare)
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Active cooling of low-concentrating hybrid PV/Thermal collectors
- 1999
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Ingår i: North Sun. - Edmonton, Canada.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A series of measurements on the performance of solar cell string modules with low-concentrating CPC reflectors with a concentration factor C ˜ 4X have been carried out. To minimise the reduction in efficiency due to high cell temperatures, the modules were cooled. Four different way of cooling were tested: 1) The thermal mass of the module was increased, 2) passive air cooling was used by introducing a small air gap between the module and the reflector, 3) the PV cells were cooled by a large cooling fin, 4) the module was actively cooled by circulating cold water on the back. The best performance was given with the actively cooled PV module which gave 2,2 times the output from a reference module while for the output from the module with a cooling fin the value was 1,8. Active cooling is also interesting due to the possibility of co-generation of thermal and electrical energy which is discussed in the paper. Simulations, based on climate data from Stockholm, latitude 59.4°N, show that there are good prospects for producing useful temperatures of the cooling fluid with only a slightly reduced performance of the electrical fraction of the PV thermal hybrid system.
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- Rönnelid, Mats, et al.
(författare)
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Experimental performance of a string module in a CPC reflector cavity
- 1998
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Ingår i: 2nd World Conf. on Photovoltaic Energy Conversion. - Vienna, Austria.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The purpose of the work is to develop a cost effective semistationary CPC concentrator for a string PV-module. A novel method of using annual irradiation distribution diagram projected in a north-south vertical plane is developed. This method allows us easily to determine the optimum acceptance angle of the concentrator and the required number of annual tilts. Concentration ranges of 2-5x are investigated with corresponding acceptance angles between 5 and 15°. The concentrator should be tilted 2-6 times per year. Experiments has been performed on a string module of 10 cells connected in a series and equipped with a compound parabolic concentrator with C = 3.3X. Measurement show that the output will increase with a factor of 2-2.5 for the concentrator module, compared to a reference module without concentrator. If very cheap aluminium reflectors are used the costs for the PV-module can be decreased nearly by a factor of two.
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| 10. |
- Rönnelid, Mats, et al.
(författare)
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Static Concentrators for Photovoltaic Modules at High Latitudes
- 1996
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Ingår i: EuroSun 1996. - Freiburg, Germany.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The paper gives an analysis of the performance of the photovoltaic modules with planar booster reflectors with variable length and tilts for Swedish conditions. The booster reflector for photovoltaic modules of crystalline silicon cells should be designed so that an even illumination over the module is obtained since the cells in the module are connected in series. However, if amorphous silicon or thin film modules are used, the module can be placed with the length of the cells extended north-south. In this geometry the cells which are connected in series in the module always obtain the same average irradiance, and reflectors of a shorter length can be used compared to a design where the whole module has to be evenly illuminated. A specular booster mirror with reflectance = 0.8 in front of an east-west aligned PV module with one third of the reflector area increases the annual irradiation by about 25% with allowance of uneven illumination on the module plane and no requirement for tracking. The additional cost for the reflectors is of the order of 10 % of the cost of the modules, which means that installation of a booster mirror is cost effective compared to increasing the module size.
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