Experimental investigation of a novel hybrid solar-geothermal desalination process

Abstract

The widespread application of renewable energy, particularly in water desalination, is critical for addressing global water scarcity. This paper proposes a novel hybrid sustainable desalination method that harnesses both solar and shallow geothermal energy through evaporation and condensation processes. The desalination device under consideration uses a parabolic trough solar collector to evaporate saline water, and then transports the generated water vapor to an underground vertical conduit. The vapor cools as a result of the underground low temperature, leading to condensation and the formation of fresh water. To assess the freshwater production capacity of the proposed system, a simple lab-scale prototype was developed. The experimental prototype's findings emphasize the substantial influence of temperature and velocity of water vapor at the inlet of the buried pipe on the efficiency of freshwater production. Despite its small scale, the prototype outperforms other solar desalination methods, producing a remarkable output of 740 ml/h of fresh water under specific conditions (temperature: 53 °C, velocity: 1.4 m/s) With an estimated productivity of 90 l m−2 day−1,the present desalination prototype is more effective when compared with other earlier experimental studies of solar desalination systems such as active solar still and humidifier, dehumidifier solar systems, This research contributes to the advancement of sustainable desalination technologies, holding promise for addressing water scarcity challenges globally.