Experimental Study of Close-Packed Evacuated-Tube Collector Under the Weather Condition of North China
Abstract
Evacuated-Tube Collector (ETC) plays an important role in the efforts against energy shortage and climate change in China, where it is mainly used for solar water heating and the market share is the largest all over the world. In this paper, an experimental study was implemented for the close-packed ETC, tube spacing of which is just 3mm. Also an ordinary ETC was studied for comparison. The experimental system was established in Tianjin, north China. Tianjin is located in the climate division of cold zone, a typical region in China for the application of solar water heating. Experiment was conducted all through the year, the gained heat as well as the collector efficiency were worked out. The results from the experiment revealed that the close-packed ETC efficiency is 25-30% higher than that of ordinary ETC. This improvement on the efficiency is valued for the solar water heater industry in China. Also in this paper simulation was carried out to study the influences of wind speed to the mechanics performance of closed packed ETC, to provide guide to the engineering and installation.