Improving a diffusion absorption refrigeration cycle supplied with the exhaust waste heat of an automobile at low engine speeds

A diffusion absorption refrigeration cycle as a car refrigerator, which uses the car exhaust waste heat as a heat source of the cycle has been simulated in this study. An internal combustion engine with a volume of 1.3 liters at different engine speeds and throttle openings was examined experimentally and exhaust conditions such as flow rate and temperature were used as the input of the cycle. Eventually, for engine speeds above 2000 rpm, there was no trouble and the evaporator temperature ranged from -0.4oC to -7.1oC. For 1500 rpm and 1000 rpm, the evaporator temperature did not reach the desired range of variations, which is the case in other reported researches. There is no available solution for the situations where the engine is running at low speed such as in traffic jam or idle condition. Therefore, a new generator was designed and simulated to solve this problem. The simulation results show that by using the modified generator, the heat transfer to the generator improves by 16.8% on average. Consequently, the cooling capacity increases by 4.7%. Therefore, the current diffusion absorption cycle is capable of performing well at the low engine speeds.