Experimental evaluation of the energy efficiency of a CO2 refrigerating plant working in transcritical conditions

摘要

This work presents the experimental evaluation of the energy efficiency and optimal gas-cooler pressures of a single-stage refrigerating plant working with carbon dioxide as refrigerant in transcritical conditions. The performance of the plant was tested at three different evaporating temperatures (-0.9, -10.1 and -18.1 °C), for three gas-cooler refrigerant outlet temperatures (31.2, 33.6 and 40.0 °C) at each evaporating temperature and in a wide range of gas-cooler pressures (74.4-104.7 bar). The experimental tests enabled us to calculate accurately the optimal gas-cooler pressures and compare them with the most commonly used relations to define this value in single-stage refrigerating cycles operating with carbon dioxide in transcritical conditions. Furthermore, an analysis of the reduction in energy efficiency produced in the plant if the optimum pressure is not well defined is also presented. © 2007 Elsevier Ltd. All rights reserved.