Integration of Heating and Air Conditioning into a CO_2 Trans-Critical Booster System with Parallel Compression Part I: Evaluation of key operating parameters using field measurements

摘要

This paper investigates key operating parameters of a supermarket in Sweden where heating and air conditioning arernintegrated into the CO_2 trans-critical refrigeration system. The Supermarket has applied several features of a state-of-theartrnsystem including space and tap water heating, air conditioning, and parallel compression.rnUsing field measurements data, the key operating parameters in the CO_2 system are studied in a warm summer monthrnand a cold winter month.rnThe warm month study shows that the CO_2 system provides the required temperatures for air conditioning demands; thernpressure in the receiver is regulated to provide 7-8℃ forward secondary fluid. Parallel compression is used to controlrnthe receiver pressure for ambient temperatures higher than 15℃.rnThe high pressure side of integrated CO_2 system is controlled mainly for heat recovery in winter. The pressure is fixedrnto 80-85 [bar] and the gas cooler is by-passed to recover the entire rejected heat when ambient temperature is very low.rnThe heat recovery function of the system is analysed for both tap water and space heating circuits. The measurementsrnshow that the system is able to provide the high tap water temperature of 55-60℃ throughout the year. The system isrnalso able to provide the space heating forward temperature of up to 45℃.rnAnalysis of the key operating parameters of the integrated CO_2 system shows that it fulfils the temperature requirementsrnof refrigeration, air conditioning, hot water, and space heating. The loads and energy efficiency of these functions of thernsystems have been studied in part II of this paper.