Investigation on a two-stage ejection refrigeration system

Working under high condensing or low evaporating temperatures, a two-stage ejection refrigeration system is presented in order to effectively utilize low-grade heat in this context. The performance of the two-stage ejection refrigeration system is investigated under generating temperatures from 130 to 150 degrees C, condensing temperatures of 45-54 degrees C and evaporating temperatures from 6 to 30 degrees C. The experimental results show that the presented two-stage ejection refrigeration system can operate normally under a condensing temperature of 54 degrees C, which is higher than the normal condensing temperatures of a single-stage ejection refrigeration system. However, the extra power input to drive the 2nd ejector make such a system less efficient under condensing temperatures below 50 degrees C. Under those circumstances, through adjustment of operational strategies, an ejection refrigeration system should choose using single-stage ejector or two-stage ejector for different operational conditions, which greatly extends the application range of ejection refrigeration systems. (C) 2015 Elsevier Ltd. All rights reserved.