DEVELOPMENT OF 12.5 M2 SOLAR COLLECTOR PANEL FOR SOLAR HEATING PLANTS

摘要

Theoretical investigations have elucidated how different changes in the design of the 12.5 m² flat-plate solar collector panel HT from Arcon Solvarme A/S influence the solar collector efficiency and the yearly thermal performance of the collector panel. The HT collector is based on an absorber consisting of 16 parallel sunstrips, a cover system consisting of a glass cover and a Teflon foil and glass wool as insulation material. Changes of the following parts of the solar collector were included in the investigations: Number of parallel sunstrips of the absorber, emittance and absorptance of the sunstrips, glass cover type, antireflection treatment of glass cover, insulation material, and solar collector fluid. Based on the findings a prototype of an improved HT solar collector was built and tested side-by-side with the original HT solar collector. The improved HT collector makes use of a changed insulation material, a sunstrip absorber with increased absorptance and decreased emittance, and a changed antireflection treated glass cover. The measurements showed that the efficiencies for the original and the improved HT solar collector for small incidence angles were: HT original: η=0.75－2.69×((T_m－T_a)/G)－0.0050×((T_m－T_a)ˉ2/G) HT improved: η=0.82－2.44×((T_m－T_a)/G)－0.0050×((T_m－T_a)ˉ2/G)The measurements also showed that the incidence angle modifiers for the two collectors were: HT original: k_θ = 1- tanˉ2.8 (θ/2) and HT improved: k_θ= 1 －tanˉ3.6(θ/2). The measured efficiencies are in good agreement with the calculated efficiencies. Calculations showed that the yearly thermal performance of the improved HT collector is 23% -37% greater than the thermal performance of the original HT collector at operation temperatures between 40°C and 80°C.