Ejector expansion transcritical R744 refrigeration system analysed for various climate zones of India

Abstract

Ejectors can provide advantage over conventional expansion device, in terms of energy as well as exergy, especially in high pressure transcritical R744 refrigeration systems. This paper presents a simulation-based comparative study of annual energy consumption and environmental impact of four different configurations of ejector expansion R744 systems for thirty different cities in India, spread across five different climatic zones. A control strategy is also adopted in order to ensure smooth transition of operation between subcritical, transcritical and transition modes for round the clock operation. A configuration having multi-compression ejector expansion system equipped with internal heat exchanger (MCEETRC+IHX) along with suggested control strategy exhibited lowest annual energy consumption. However, all the components are not equally effective for all the cities or weather conditions. Ambient temperature and evaporator temperature are found to play an important role. A simplified economic analysis is also presented which suggests overall cost-effectiveness for supermarket food storage application.