Experimental investigations on a sustainable cogeneration system for power and desalination with 4-E analysis

Abstract

Several research investigations were carried out on the potential integration of solar stills with photovoltaic modules to improve freshwater production and electric output. The current work aims at integrating stepped solar still (SSS) with a bi-directional flow serpentine thermal absorber-based Photovoltaic-Thermal (PVT) module. Near the vernal equinox days, a laboratory-scale experimental facility is designed, developed, and tested in Vellore (12.9165° N, 79.1325° E). The novelty of the proposed system is that it effectively utilizes the waste heat recovered from PVT with a unique thermal absorber for preheating saline water supplied to the SSS. Experiments were carried out on a PVT-SSS system to estimate the electricity and freshwater generation by PVT and SSS for saline water flowrates of 0.3, 0.5, 0.75, and 1.00 LPM. The estimated average electrical efficiency of the PVT panel is 14.84 %, 15.46 %, 14.74 %, and 14.50 %, and the freshwater productivity from SSS is 3460 ml, 2970 ml, 2460 ml, and 1950 ml per square meter. The average thermal efficiency of the proposed PVT-SSS system is 34.5 %, 31.8 %, 20.1 %, and 16.3 %; 49.36 %, 47.30 %, 34.90 %, and 30.83 %, respectively, for the mentioned flow rates. Further, the average exergy efficiency of the system is observed as 18.5 %, 18.7 %, 17.2 %, and 16.6 %, respectively. In addition, the unit cost of freshwater production for various flow rates in USD is estimated as 0.07, 0.08, 0.09, and 0.10, respectively. An environmental analysis was also performed to determine the CO2 emissions and carbon mitigation for the proposed hybrid desalination system. The results are validated with previous literature.