An experimental investigation of an adsorption refrigeration system based on a silica gel-water pair

Abstract

Adsorption refrigeration technology is under much research with the increasing demand to protect our environment, and also to reduce the use of Earth's resources, since it is powered by waste heat or renewable energy, and also does not require the use of environmentally harmful refrigerants.

This report presents an experimental study of a newly designed single adsorbent bed to be used in an existing experimental facility as developed by previous final year project students. The adsorbent bed designed is a fin‐tube assembly that is to be packed with silica gel and enclosed in a wire mesh, and the focus of the design was to enhance heat transfer between the adsorbent and the adsorbate. This was accomplished by using copper water pipes and copper plate fins, which was determined to have 30 times the thermal conductivity of stainless steel.

The newly designed adsorbent bed was able to maintain vacuum conditions for at least 48 hours without any leakage, and the performance of the modified adsorption system was experimentally tested by varying the generation temperature of the cycle.

The results of the experiment showed no improvement in terms of the COP of the system, with a 0.003 drop in COP of the modified system as compared to the previous system using similar parameters. The SCP of the modified system, however, was found to be approximately 15 times better, and its TCP approximately 3 times better, than the previous system.