Performance study of an adsorption refrigeration system based on the silica gel/water pair

• Main Author: Wang, Kelvin.
• Other Authors: Leong Kai Choong
• Format: Final Year Project
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering::Mechanical engineering
• Online Access: http://hdl.handle.net/10356/53591
• Institution: Nanyang Technological University

Adsorption refrigeration technology has been around since the 1990s and has been increasing made popular by researchers all around the world due to the increased need to protect our environment and also to reduce the use of Earth's resources. The reason is because it is powered by waste heat or renewable energy and also does not require the use of environmentally harmful refrigerants. This report presents a performance investigation of an adsorption refrigeration system after modifications done to single adsorbent bed, condenser and evaporator tank 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 was packed with silica gel and enclosed in a wire mesh. 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 evaporator and the condenser are stainless steel vacuum tanks that have higher power capacity than the previous model. The newly modified system with vacuum standard fittings was able to maintain vacuum condition for at least a week without any leakage and the performance of the modified adsorption system was experimentally tested based on only one generation temperature of the cycle. The desired cooling was not achieved but found that for a small quantity of silica gel, the size of the evaporator tank should be relatively small so that cooling can be achieved. Vice versa, if the evaporator tank is big, the amount of silica gel used in the adsorbent bed should also increase.