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Experimental evaluation of the seasonal energy efficiency rating for a trans-critical R744 booster system in various climate conditions.

Number: pap. n. 7

Author(s) : JAVERSCHEK O., REICHLE M.

Summary

CO2 booster systems represent the most common system type for trans-critical CO2 applications in commercial refrigeration. Booster systems are characterized by a common refrigerant and lubrication circuit, where the compressor of the low-temperature stage discharges directly into the suction-side of the medium-temperature (MT) stage compressor. Despite of the fact that booster systems typically operate with higher suction gas temperatures and consequently, lower suction gas densities in the MT stage compared to cascade systems, these systems usually still have higher energy efficiencies. The main reason is the temperature difference required in the cascade heat exchanger, resulting in an increased pressure ratio and finally power consumption by the compressors in the low-temperature stage. As the energy efficiency of booster systems strongly depends on the ambient temperature, the location of the system significantly affects the annual power consumption. An analysis of the Seasonal Energy Efficiency Rating (SEER) illustrates the potential of trans-critical applications for a particular location. In this study, the SEER of a booster system is experimentally evaluated for three different climate zones, namely Athens, Strasbourg, and Helsinki. Published data of the ECO-Efficiency Study for supermarket refrigeration are taken into account in order to determine the SEER. The experimental facility utilized is a state-of-the-art trans-critical CO2 booster system with flash gas bypass which is installed by BITZER at its Rottenburg site for practical training seminars. Medium temperature load as well as low temperature load are realistically simulated by means of a cold storage room and a freezing cabinet, respectively. Furthermore, a discussion of the measured results is presented.

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Pages: 9 p.

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Details

  • Original title: Experimental evaluation of the seasonal energy efficiency rating for a trans-critical R744 booster system in various climate conditions.
  • Record ID : 30008724
  • Languages: English
  • Source: Compressors 2013: 8th International Conference on Compressors and Coolants.
  • Publication date: 2013/09/02

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