A novel design of passive cooler for PV with PCM and two-phase closed thermosyphons.

• Combination of PCM and TPCT in a passive cooler for a PV has increased efficiency. • While the PCM was absorbing heat, the heat transfer to ambient is insufficient. • Heat transfer from PCM with TPCT type heat pipes gave good results. • Better results can be obtained in TPCT with fluids with higher thermal conductivity. In this paper, in order to increase the efficiency of a photovoltaic (PV) panel, thermosyphon (Ts) type heat pipe-assisted passive cooling technique has been investigated experimentally. For this, two different passive cooling designs are applied to the reference panel (Rf). In the first design, passive cooling was performed by paraffin alone (Pr). For the second design, submerging thermosyphons in paraffin (Pr + Ts) was performed. In order to obtain a better see the effect of thermosyphons in the proposed new passive cooling design, methanol (mTs) was used as a working fluid in one group of thermosyphons and water (wTs) was used in the other group of thermosyphons. Experiments were carried out with solar simulation using an incandescent lamp under laboratory conditions. During the experiments for each design, the average outdoor temperature was measured at 21 °C. Experimental results and theoretical calculations have shown that passive cooling with thermosyphons is effective in increasing efficiency by reducing the front glass surface temperature of the PV panel. While the average front glass surface temperature was 54.9 °C in Rf, it was 53.6 °C, 50.5 °C and 49.5 °C in Pr, Pr+mTs and Pr+wTs, respectively. The best efficiency enhancement was achieved with Pr+wTs and the efficiency of Rf was improved by about 6%. In this study, paraffin as PMC, and thermosyphons were used together, and their experimental performances were compared. Thus, it is aimed to introduce a new passive cooler design to the literature. [ABSTRACT FROM AUTHOR]