Absorption refrigeration system using engine exhaust gas as an energy source

• Main Authors: Sorawit Kaewpradub, Prawit Sanguanduean, Wattanapong Katesuwan, Nares Chimres, Phatthi Punyasukhananda, Lazarus Godson Asirvatham, Omid Mahian, Ahmet Selim Dalkilic, Somchai Wongwises
• Format: Article
• Language: English
• Published: Elsevier 2018-09-01
• Series: Case Studies in Thermal Engineering
• Online Access: http://www.sciencedirect.com/science/article/pii/S2214157X18302314

A single-effect absorption refrigeration system that uses LiBr-water solution and engine exhaust gas is investigated. The generator is a spiral fin-and-tube heat exchanger, while the condenser, evaporator, and absorber are shell and coil heat exchangers. Experiments are conducted at engine speeds of 1000, 1200, 1400, and 1600 rpm; expansion valve opening percentages of 54.5%, 72.7%, and 90.9% at the separator outlet and 3.41%, 4.55%, and 5.68% at the condenser outlet; refrigerant temperatures at the condenser outlet of 25, 30, and 35 °C; and LiBr-water solution flow rates of 0.35 and 0.7 LPM. The results show that the system could work with an engine speed of 1200–1400 rpm. The cooling load and coefficient of performance (COP) increase with increasing engine speed. The highest COP of 0.275 is reached at an engine speed of 1400 rpm, opening percentage of 72.7% at the separator outlet and 4.55% at the condenser outlet, water temperature of 25 °C at the condenser outlet, and LiBr-water flow rate of 0.7 LPM. The decreased refrigerant temperature at the condenser outlet helps to increase both cooling load and COP. The increase of the LiBr-water solution flow rate helps to increase cooling load but decrease COP. Keywords: Absorption refrigeration, LiBr-water solution, Exhaust gas, COP