Evacuated tube heat pipe solar collector for Encontech engine‐driven reverse osmosis solar desalination

Abstract

Utilization of a single evacuated tube heat pipe solar collector (ETHPSC) for the efficient deployment of the solar energy toward driving the Encontech heat engine for reverse osmosis desalination is considered in this study. The effects of the mass flow rate of water , inlet temperature (T i), solar intensity (I), the ratio of the condenser to absorber area (A co/A abs), heat transfer coefficients ( h air and h vacuum) on energy and exergy efficiency (η, η Ex), the absorber ( T abs), condenser ( T co), and the outlet temperature ( T o) are explored by using a heat transfer resistance model. An open-source SCILAB software was used for performing the computer simulations. The simulation results show that for each h air there is an optimum T i (based on the exergetic performance). The lower h air and h vacuum appears to be more promising to improve the efficiency and temperature gain ( T i − T o) of the ETHPSC. The maximum energetic efficiency of 52.5% is obtained for h vacuum (1 W/m2 K). Obtained results further demonstrate that the energetic and exergetic performances of the ETHPSC are higher at T i = 50°C. Both energetic and exergetic efficiencies exhibit upper values at A co/A abs ratio up to 1. Further increment in this ratio up to 3 resulted in a decrease in the efficiency of the ETHPSC.