Exergy Analysis of Single-Effect Vapor Absorption System Using Design Parameters

Abstract

Abstract In the present communication, internal irreversibility at each component of a single-effect vapor absorption refrigeration system has been evaluated and presented. The irreversibility is induced owing to the pressure drop in the shell and tube and energy exchange between the working fluids. Each component of the system is considered to be a shell and tube-type energy exchanger with slight modifications depending upon the applications. Each energy exchanger is divided into three control volumes, namely, tube wall, shell, and tube for which both energy and exergy balances are applied to evaluate the exergy destruction rate (EDR). Moreover, the overall EDR in the energy exchanger is then estimated in the form of pumping work and energy exchange duty. This objective function is further simplified in the form of design parameters such as tube diameter, friction coefficient, number of tubes, number of baffles, and overall heat transfer coefficient for the energy exchanger. In addition to this, optimum generator temperature and minimum EDR of each component of the absorption system have been tabulated and presented. Results show that for a single tube, UA value in the system component ranges from 2.99 W/K to 48.9 W/K depending on the operating conditions and design parameters of the system. Also, the number of tube in the system components ranges from 1108 tubes to 24803 tubes and the number of baffles in the respective components ranges from 2 to 7.