Simulation and Economic Analysis of Solar Thermal Cogeneration System for Production of Heat and Pure Water using Membrane Distillation

Abstract

In this paper, a novel solar thermal cogeneration (termed as solar combi MD; SCMD) system for production of clean water and domestic hot water is modeled and analyzed for the weather conditions of United Arab Emirates (UAE). The system comprises of solar collectors for production of thermal energy, thermal storage for domestic hot water generation and membrane distillation (MD) modules for clean water production gaining energy through a plate heat exchanger. The performance of cogeneration is analyzed with two different solar collectors used for domestic heating – flat plate collectors (FPC) and evacuated tube collector (ETC). The system is modeled and dynamically simulated using TRNSYS software for optimization of various design parameters like collectors tilt angle, mass flow rate through MD loop, thermal store volume and heat exchanger effectiveness. Cogeneration system efficiencies and collector areas has been determined for optimum conditions. Economic benefits are analyzed for FPC collectors and fuel costs savings compared to individual system operation. Total investment cost of SCMD system for single family application would be around 5000$ with an impressive payback period of 5.5 years which is 30% lower than regular SDHW installations.