Annual energy and economic performance assessment of transcritical R744 supermarket refrigeration systems powered by an organic Rankine cycle

In this work the annual and economic performance of a transcritical R744 booster supermarket refrigeration system integrated with an organic Rankine cycle (ORC) was investigated. The results were compared to those of a conventional R744 booster supermarket refrigeration system (i.e. without ORC) in nine different locations worldwide. The benefits from overfeeding the medium temperature (MT) evaporators were also studied. It was found that the ORC can be used at outdoor temperatures above 27 °C. Also, it was observed that the proposed systems offer energy savings from 6 % to 16 % in warm and hot locations, such as New Delhi (India), Phoenix (USA), Bangkok (Thailand) and Riyadh (Saudi Arabia). The payback period of the additional investment associated with the ORC was equal to about 3.5 years in Athens (Greece) and less than 1.5 years in New Delhi, Phoenix, Bangkok and Riyadh.