Cooling performance study of a novel heat exchanger in an absorption system

The paper is focusing on a shell and plate heat exchanger of a novel absorption refrigeration system. The system is composed of two vacuum vessels connected together with a steam channel and one heat exchanger is located in each vessel. The first heat exchanger is called reactor where working fluid and salt exist and the second heat exchanger or evaporator/condenser (C/E) is where only water exists. The propylene glycol-based (PG) heat transfer fluid is used on the shell side of both heat exchangers as the media to exchange the heat between boilers and reactor in one vessel and between cold environment and condenser/evaporator in another vessel. An experimental test rig was built to investigate the performance of the evaporator/condenser heat exchanger. Then, a three-dimensional (3D) Computational Fluid Dynamics (CFD) model was developed. The experimental result was then used to validate the numerical model developed by using Ansys/Fluent software. A parametric study has been intended to find a more appropriate design for the heat exchanger in order to increase heat transfer performance. Results of the parametric study demonstrated that the cooling performance is doubled by increasing the diameter of the plate from 0.14 m to 0.2 m. In addition, to obtain the maximum heat transfer performance, Reynolds number and distance between plates should be 9 and 0.5 m, respectively. Two correlations have been developed for the outlet temperature and cooling power of the heat exchanger which are functions of heat transfer coefficient. The results of this study can be of vital importance for improving the cooling power of the system, remarkably.