A simplified design procedure of R134A-DMAC plate type bubble absorber for vapour absorption refrigeration system

Vapor absorption refrigeration systems (VARS) are having great advantages as they use low grade energy like heat, very few moving parts, and almost its performance is independent of refrigerating load fluctuations. However, the working characteristics of vapor absorber and generator significantly affect its overall performance and compactness. From the intensive review of existing literature, it is found that very few studies are reported for designing a water cooled plate type bubble absorber which can be used for R134a-DMAC. This report describes a simplified procedure to design R134a-DMAC plate type bubble vapor absorber. The procedure includes solving techniques of the mass and energy equations related with VARS. The heat and mass transfer characteristics along the length of absorber of R134a-DMAC mixture, and coolant are obtained by using the thermo-physical properties experimental correlations for enthalpy, dew and bubble point temperatures, specific heat, density, viscosity, thermal conductivity and mass diffusivity. In addition, the coefficients of heat and mass transfer are found by employing the empirical correlations which are explained in terms of temperature, pressure and mole fraction. All the equations and the correlations are solved by splitting the whole absorber into small control volumes and subsequently each control volume is divided into liquid, vapor and coolant segments. A computer program in MATLAB is developed and tested to find the various specifications of absorber like number of plates, width, height and thickness of plates, coolant and solution passage, etc.