Optimization and application of tube pitch for evacuated tube solar collector

CHAI Ting1， HU Hai-tao1， DING Guo-liang1， ZHANG Ke2， LI Hong-da2， YU Yong-kui2
（1. School of Mechanical Engineering， Shanghai Jiaotong University，Shanghai 200240，China；
2. Honeywell （China） Co.，Ltd.， Shanghai 201203， China）

Abstract： In order to improve the performance and decrease the cost of solar water heater，the optimization of evacuated tube solar collector was done by considering both the performance and the cost. The optimization model of tube pitch for the evacuated tube solar collector was developed，and the optimization object is the cost per unit energy gain. The optimization model included a collector cost model，and a solar energy gain model in which the solar radiation and the effect of shadow between tubes were taken into consideration. A case study of the model on commonly used solar collector shows that the cost per unit energy gain and the total cost of solar collector are decreased by 1.5% and 4.6%，respectively.
Key words： evacuated tube； solar collectors； solar collecting performance； cost； tube pitch