Thermodynamic analyses of an innovative system combined dehumidification, cooling and heating driven by solar energy

Abstract

For the sake of improving the utilization of solar energy in hot summer and cold winter areas of China, an innovative system combined liquid dehumidification with absorption refrigeration driven by solar energy is proposed in this paper. Solar energy is applied to three subsystems in a cascade utilization approach. Energy, exergy, and dehumidification performances of the system in three typical seasons of hot summer and cold winter areas in China are analyzed and compared. The key parameters including solar radiation intensity, ambient temperature, segment temperature and air relative humidity are investigated to obtain the optimization design of the proposed system. The objective indicators, including dehumidification coefficient of performance, refrigeration coefficient of performance, exergy efficiency, moisture removal rate, humidity efficiency, cooling capacity and heating capacity are discussed, respectively. The results show that, as the ambient temperature and solar radiation intensity increase, the dehumidification coefficient of performance (COPD) declines but the refrigeration coefficient of performance (COPR) rises. The COPD in rainy season is increased by 33.66 % and 50.15 % respectively, compared with that in cooling season and heating season. But the COPR in cooling season is 35.32 % higher than that in rainy season. The minimum of COPD reaches 1.31 at 12 noon. The maximum of COPR in the proposed system is 0.95. The exergy efficiency of the proposed system is improved by combining the liquid dehumidification subsystem and absorption refrigeration subsystem, with the maximum reaching 16.64 %. The proposed system shows better dehumidification performance in rainy season, and the maximum moisture removal rate and humidity efficiency in the proposed system are 27.98 g/kg and 0.83. The proposed system is also used for cooling and heating, with the highest cooling capacity and heating capacity achieving 217.31 kW and 36.58 kW, respectively. The obtained results state that the proposed system has excellent performance for dehumidification, cooling, and heating in hot summer and cold winter areas of China.