Abstract—In the recent years, the research interest on Diffusion Absorption Refrigeration (DAR) technology has increased significantly due to its ability to utilize exclusively low-grade heat to produce cooling effect. The operation of diffusion absorption refrigeration system is quiet and reliable therefore often used in hotel rooms and offices. The diffusion-absorption cycle utilizes ammonia-waterhydrogen as working fluid. In this paper, a mathematical model has been established and solved numerically. The model is based on the mass and energy conservation principles applied for every components of the DAR system, through which the working fluids flow. Equations have been developed to estimate mass flow rate, mass concentration and enthalpy of different fluids at various state points of the cycle by considering the mass balance and heat balance equations. Suitable thermodynamic relations have been used for estimating enthalpies at various points corresponding to their state properties of pressure, temperature and dryness fraction. The study showed that the COP of this refrigeration system, although not comparable with the COP of a vapour compression cycle, is encouraging, considering the fact that waste heat can be utilized for running the cycle and COP of the DAR system depends on different parameters like generator temperature, concentration of ammonia in rich solution, evaporator temperature and condenser temperature.

Index Terms—Ammonia-water, Bubble pump, COP, Circulation ratio, Diffusion absorption refrigeration

Cite: Mukul Kumar and R K Das, "Thermodynamic Study of Diffusion Absorption Refrigeration System with Organic Fluid," International Journal of Mechanical Engineering and Robotics Research, Vol. 4, No. 1, pp. 473-484, January 2015.