24 June 2014

Waste Heat Recovery Analysis of CO2 Refrigeration Systems

This paper presents a comparative analysis of various CO2 transcritical
supermarket refrigeration systems for a range of operating conditions. The performance of the CO2-based refrigeration systems is compared with the baseline R-404A multiplex direct
expansion system using bin analyses in sixteen cities from eight climate zones of the United States. Finally, the potential for utilization of waste heat from transcritical CO2 refrigeration
systems, for application in desiccant regeneration, water heating and space heating, has been analyzed. The analysis has revealed that the Transcritical Booster System with Bypass
Compressor (TBS-BC) had the lowest energy consumption for ambient temperatures (Tamb) less than 8°C. Also, the TBS-BC performs equivalent to or better than the R-404A direct
expansion system in the northern two-thirds of the US. For the southern portion of the US, the R-404A multiplex DX system outperformed the transcritical CO2 systems. It was found
that heat recovery from transcritical CO2 systems could nearly satisfy the desiccant regeneration and water heating needs of a supermarket for all climate zones in the US, while
partially meeting the space heating requirements.