Improving the performance of evacuated tube of a solar collector with acetone-based heat pipe using the desert sand as thermal storage material

Abstract

In view of the many problems fossil fuels cause in terms of environmental damage and their time-changing costs, the use of renewable energy has become imperative. Solar collectors are a good solution for many uses, most importantly heating. Therefore, we are seeing a significant trend towards the development of this mechanism and its improvement. Problems with solar collectors are that heat from solar radiation is not well stored. Using materials with good heat specifications as a thermal storage material is a good solution to the problem of heat loss. In this study, the desert sand was used as a thermal storage material that improves thermal performance and better thermal storage in solar communities. The first part was using evacuated tubes solar collectors without a heat pipe, in the first case three different sizes of the desert sand were used: 1-desert sand DS6 (grain diameter=0.6mm). 2-desert sand DS3 (grain diameter=0.3mm). 3-mixed desert sand MDS (mixing from last two types). In the second case, MDS was used with the addition of copper filings where it was mixed perfectly. In the third case, MDS was used and oil was added. The results showed a significant improvement in the thermal performance of solar collectors compared with non-thermal storage material studies, where the highest temperatures were recorded for the third cases (225.7, 271.4, 261.7°C) respectively. In addition to good thermal storage, temperatures were high during the evening, in this part, the evacuated tubes were completely isolated. In the second part, a heat pipe is studied in the evacuated tube solar collector HPETSC, the same conditions as in part one were studied. In the first case, MDS was studied, in the second case copper filings were added to the MDS, and in the third case, oil was added to the MDS. However, in this part of the evacuated tubes, it was not isolated from the surrounding, there was a part of the heat pipe that exchanged heat with the surrounding. The results showed a good improvement in the thermal performance of the solar collector, with the highest temperatures recorded in third cases (192.8, 211.2, 202.5°C) respectively, with the thermal storage maintaining a high temperature during the absence of solar radiation.