Experimental Study on LiNO<sub>3</sub>-NH<sub>3</sub> Diffusion-Absorption Refrigeration System

Abstract

In order to utilize solar energy and industry waste heat to reduce electricity consumption in heating, ventilating, air conditioning and refrigerating (HVAC&R) engineering, the authors developed a new style diffusion-absorption refrigeration (DAR) system. It can be driven by heat sources with low temperature, and in which LiNO3-NH3-He is used as working fluids and a spray absorber with a solution cooler is designed to enhance the mass and heat transfer, respectively. What presented here is about the modified experiment set and the latest experiment results. The experiments show that the system can start to operate when the temperature of heat source (hot water) reaches to 60°C and it can meet the temperature requirement of air conditioning when heat source temperature varies in the range of 70～83°C. The evaporating temperature varies from 10～-13°C at various absorbing temperatures when heat source temperature reaches the level of 83～95°C. The corresponding refrigeration capacity and coefficient of performance (COP) varies in the range of 1.90～4.22kW and 0.177～0.332, respectively. It is also found that the evaporating temperature, refrigeration capacity and COP are so sensitive to absorbing temperature rather than generating or condensing temperature that the absorbing temperature can be used to regulate the working condition and parameters of the DAR system, e.g. by means of modulating the flow rate of cooling water circulating in the solution cooler equipped to the spray absorber. Thus, in the fields with plenty of solar energy or industry waste heat, the new style DAR system can be considered as an ideal candidate for utilizing low-grade energy, saving energy and reducing emission.