Supermarket application. Effects of sub-cooling on real R744 based transcritical plants in warm and hot climate. Data analysis.

Several techniques are under development worldwide to expand the convenient use of Carbon Dioxide (R744) in region with high external temperature. This paper analyses the effect of a sub-cooling device in real R744 trans-critical plants for supermarket application. A sub-cooling device is a system able to assist a gas cooler to cool a stream of trans-critical R744 before its expansion in the high pressure valve. The aim of the study is to understand how much the presence of a sub-cooler device helps the efficient use of R744 for refrigeration in commercial application in the hot and warm temperature region. The use of the sub-cooler reduces the discharging temperature and pressure peaks, as well as the power peaks and the overall energy consumption. This paper analyses a collection of data coming from different stores equipped with sub-cooling in order to compare them with stores without the sub-cooling device. Stores with different sub-cooling techniques have been analyzed such as mechanical, groundwater and integration with A/C.