Study On Thermal Performance Of A New Solar Air Collector With Colored Facade (SCCF)

The traditional Trombe wall has been widely applied in many countries and areas for the sake of easy construction, low cost and fine heat collection. The total building area of passive solar house in rural of North China had amounted to 18 millions square meters until the end of 2004, resulting in about 360 thousands tons of standard coal can be saved per year. However, the usual overheating of indoor air in summer and difficult alteration and maintenance for existing houses still restrict the further development of this style solar building. Therefore, an advanced Solar air Collector with Colored Facade (SCCF: China Patent No.: ZL022209863.1) is introduced in this study to deal with these problems. It has the abilities of both heating and cooling, and can also be used as an insulated plate during night in cold winter to reduce heat loss from windows.In this study, thermal performance of SCCF in a real building was investigated. Heating effect in daytime and insulation effect during night in winter and cooling effect in summer were respectively evaluated by field experiment, macroscopic theory model and numeric simulation with Fluent software. Some influencing factors such as aspect ratio, fin position, angle of absorber plate and vent area were discussed, and optimal design methods were provided in the end.With field measurement and calculations during the past two years, several constructive conclusions can be obtained as follows: (1) The air temperature difference between the upper and lower vent can reach up to 38℃. Heat-collecting effect of SCCF installed on south wall is better than that of west wall; (2) The air temperature difference between the upper and lower vent of SCCF with aspect ratio of (H/W)_B=0.4 is 13℃ higher than that of (H/W)_A=1.9. Increasing the aspect ratio helps to improve thermal performance of SCCF, but the value of aspect ratio can't be too large, and the optimal value is H/W=2; (3) The fin angle obviously affects the air temperature of upper and lower vents, and the air temperature difference between them can be increased by about 4～7℃ as the angle changes from 45° to 80°. The heating capability is best with the fin angle of 70°. The fin angle should be kept larger than 50° to obtain long term performance in practice; (4) The less thickness of air space, the better for heat collection. It can be noticed that the thickness of air space has little effect on thermal performance of SCCF; (5) The vent area obviously affects SCCF's thermal performance, the air temperature difference between two vents with full opening will be lower than that with...