Exergy Analysis of Humidification–Dehumidification Water Desalination Unit Working under Baghdad Conditions

Abstract

Water desalination unit powered by renewable energy sources is sometimes needed at places far from the energy grid lines. Consequently, even countries with rich energy resources, such as the Arabian Gulf countries, have shown strong interest in desalination processes that often use renewable energy sources. This work aims to conduct an exergy analysis of solar-powered humidification–dehumidification (HDH) unit. The exergy analysis input data are extracted from a previous work conducted in August 2020 under Baghdad conditions, 33.3∘N latitude and 44.14∘E longitude. The previous work’s HDH unit consisted of six parabolic trough solar collectors (PTSCs), with a total aperture area of 8.76[Formula: see text]m2. Meteonorm v7.3 software was used to obtain the weather data for Baghdad City, Iraq. The HDH unit results had revealed low exergy efficiency, where the maximum overall exergy efficiency was 0.305% at 12.00[Formula: see text]noon, August 17, 2020, when the salty water flow rate was 1 L/min. The unit’s overall exergy efficiencies were 0.09%, 0.16%, 0.31%, and 0.085% when the salty water flow rates were 0.8, 0.9, 1, and 1.2 L/min, respectively. Maximum exergy destructions for the HDH unit components were 0.513, 0.156, 0.332, and 0.304[Formula: see text]kW for solar radiation, dehumidifier, humidifier, and PTSC, for a salty water flow rate of 1[Formula: see text]L/min. In contrast, the overall exergy destruction of the HDH unit was 1.3[Formula: see text]kW.