Design and Fabrication of evacuated tube solar thermal collector for domestic hot water


The objective of this research is to design and fabricate solar water heating system by Investment defective materials in Iraq for domestic sector applications in order to encourage national industry. Defective neon light tube with length 120 Cm and diameter 3 Cm has been used as an outer pipe. Copper pipe with length 125 Cm and diameter 1 Cm is placed inside the glass tube and close the space between them by circular shell that is used as an inner absorber material after painting it by black non brightness coating. The space between the outer glass tube and the inner copper pipe is evacuated by using small compressor. The evacuated tubes are connected from the upper side with insulated storage tank and from lower side with circulation pump. The evacuated tubes are placed in the focal line of reflective surfaces. The efficiency of the fabricated solar collector has been measured and compared with uninsulated storage tank which put in the same conditions. These measurements are done with and without reflective surfaces. The results indicated that the temperature of water in the evacuated tube with reflective surfaces reach to 59.5 °C while in the evacuated tube without reflective surfaces reaches to 44.3 °C. The temperature of water in the evacuated tube without circulation pump reach to maximum value which about 85.3 oC. This value is greater than that of the case with circulation pump.