High-efficiency solution for an open-loop desiccant assisted solar cooling system by integrating trans-critical CO2 heat pumps: A comprehensive techno-economic assessment

Abstract

Solar cooling systems are classified into open and closed loop cycles. The latter is superior in terms of reliability and commercialization. However, the former, due to unique features to provide sensible and latent cooling separately is still under development.This work proposes a potential improvement in terms of energy performance in solar-assisted open loop cycles. The cooling system is composed of desiccant wheel, indirect evaporative coolers that require regeneration power. Such power is provided by a cutting-edge technology named trans-critical CO2 heat pump, running mostly by photovoltaic modules. Four different configurations are dynamically simulated inside MATLAB SIMULINK environment for the year interval.Based on the main simulation results, the renewable energy share of at least 50% for both electric and thermal is achieved. It could be increased up to 77% electric and 100% for thermal share. Furthermore, the parameters to optimize the cooling system performance are the heat pump COP, the recovery heat exchanger effectiveness, and the regeneration air mass flow rate. Generally, the innovative cooling system behaviour is affected by climate variations. Hence, the COP of the CO2 heat pump is starting from 2.3, which could be improved up to 6.5. It is clearly higher than the available benchmark.