Optimum generator temperature to couple different diffusion absorption solar cooling systems

• Generator temperature of different solar diffusion absorption refrigerators.
• Optimum temperature for coupling is when the global efficiency is maximal.
• Compound parabolic concentrator and evacuated tube collector activate the systems.

This paper presents the generator temperatures to achieve the highest efficiency in different solar diffusion absorption cooling systems. Ammonia-lithium nitrate (NH3–LiNO3) and sodium ammonia-thiocyanate (NH3–NaSCN) were examined as the working mixtures, and the flat-plate collector (FPC), the flat-plate collector improved (FPCI), the evacuated-tube collector (ETC) and the compound parabolic concentrator (CPC) were the thermal energy sources. The study was conducted with a simulation in steady-state conditions. The effects of the generator temperature on the global efficiency of each solar cooling system were studied. The results show that the FPC and the FPCI cannot activate the cooling system at evaporator temperatures below 0 °C and the ambient temperature is at 40 °C. At evaporator temperatures above 5 °C with an ambient temperature of 30 °C, all solar collector technologies activated different working mixtures. The optimum coupling temperatures were between 70 and 150 °C. The ETC/NH3–LiNO3 was between 5 and 54% relatively better than other technologies.