Improving the performance of heat pipe embedded evacuated tube collector with nanofluids and auxiliary gas system

An attempt was made to design an evacuated tube heat pipe solar collector (ETHPSC) with a gas package for a four-member family to supply the required energy and to evaluate the effect of different nanofluids on its performance. CuO, TiO2 and MWCNT nanofluids were used, whose performance was compared with water as the working fluid. The given system was tested in the weather conditions of Sanandaj city, Iran. The results showed the maximum temperature of output working fluid from collector was recorded in second half of august 2016 between 13:00 and 15:00 p.m. and in second half of October 2016 between 12:00 and 14:30, at which time solar radiation intensity and air temperature were at their maximum level. MWCNT, CuO and TiO2 nanofluids, owing to high thermophysical properties, had a better performance than water. The fuel consumption saving of the designed solar system, compared to the common package system, during the testing period was found to be 67.7% in August and 42.2% in October. With nanoparticles MWCNT, CuO and TiO2, compared to water, the efficiency of collector increased by 25%, 12% and 5%, respectively in August and by 25%, 15% and 7%, respectively in October. (C) 2018 Elsevier Ltd. All rights reserved.