A New Style Solar-driven Diffusion Absorption Refrigerator and its Operating Characteristics

In order to utilize clean energy such as solar energy to reduce electricity consumption in heating, ventilating, air conditioning and refrigerating (HVAC&R) engineering, the author developed a new style diffusion-absorption refrigerator (DAR) with solution pumps. It can be driven by low-temperature heat sources, in which LiNO3-NH3-He is used as working fluids and an adiabatic spray absorber with a plate-type solution cooler is designed to enhance the mass and heat transfer, respectively. This paper is mainly concern on the principle and operating performance of the DAR, especially the relationships of evaporator temperature (Te), absorber temperature (Ta) and parameters such as the volume flow rate and inlet temperature of LiNO3-NH3 solution sprayed from the top of the adiabatic spray absorber. Based on measured data and theoretical analysis, the solution circulation ratio is also presented. Analyses indicate that in this DAR system, Te mainly depends on Ta rather than condenser temperature (Tc) and generator temperature (Tg). Thus Te and the performance of the DAR can be modulated by changing parameters of the sprayed solution. The results show that this DAR system can be driven by solar energy to meet the requirements of air conditioning, freezing or else. A typical operating experiment shows when temperatures of heat source (hot water temperature Tws), Tg, Ta and Tc are 92.7°C, 87.0°C, 29.6°C and 21.6°C, respectively, the lowest Te is -13.0°C, the corresponding refrigeration capacity and coefficient of performance (COP) are 1.9 kW and 0.156, respectively.