Experimental investigation on the energy and exergy performance of a coiled tube solar receiver

In this article, an experimental investigation is carried out to examine the heat transfer characteristics of a coil type solar dish receiver under actual concentrate solar radiation conditions. During the test, the concentrated solar flux is approximately 1000 kW/m(2) at aperture. The solar irradiance is almost unchanged (650 W/m(2)) for continuous two hours in the afternoon, which is used to analyze the energy and exergy performance of the solar receiver. Experimental results show that, the efficiency of the solar receiver is normally above 70% with the highest efficiency of 82%, whereas at steady state, the efficiency is maintained at around 80%. A very low value of the heat loss factor (0.02 kW/K) could be achieved during the current steady state operating conditions. The highest value of the exergy rate is around 8.8 kW, whereas the maximum energy rate can reach 21.3 kW. In addition, the highest exergy efficiency is approximately 28%, and the highest energy efficiency is around 82%. (C) 2015 Elsevier Ltd. All rights reserved.