Performance improvement of single-junction photovoltaic systems using a new design of a heat pipe-based heat sink: Experimental study

Abstract

A newly integrated single-junction PV-heat pipe system with an innovative heat sink design comprised of an elliptical cross-section area and varied aspect ratios is proposed and experimentally investigated. Unlike the prior systems, the proposed one fits the requirements for practical applications, such as adequate cooling efficiency, ease in manufacturing, reliability, low operating and maintenance costs, noiseless and powerless operation, and so increases total system efficiency. Several experiments were carried out indoors to examine the effect of using four working fluids (Pure water, Ethanol, Methanol, and Ethylene Glycol based water solution (50 % by volume), four distinct charging ratios (50, 60, 70, and 80 %), and different heat loads to mimic the absorbed energy due to incident solar irradiance received by the solar cell. The results showed that the heat pipe with an elliptical cross-section area performed better than the one with a circular cross-section area with more than 300 W/m2 increase in heat absorbed rate at 50 ℃ oil temperature and more than 2700 W/m2 increase in heat absorbed rate at 90 ℃ oil temperature. Furthermore, when compared to other working fluids and charging ratios, the heat pipe filled with Ethanol as the working fluid and a charge ratio of 70 % performs better for all operating temperatures tested and aspect ratio. The reduction in PV module temperature ranging from 9 to 16.36 ℃ depends on the working fluid, charging ratio and the operating temperature. While the increase in the PV module output power ranging from 4 to 8.18 % at the different working fluids, charging ratios and operating temperatures.