Refrigeration systems are crucial in retail food stores to ensure appropriate merchandising of food products.
This paper compares four different CO2 refrigeration system configurations in terms of cooling performance,
environmental impact, power consumption and annual running costs. The systems studied
were the conventional booster refrigeration system with gas bypass (reference system), the all CO2 cascade
system with gas bypass, a booster system with a gas bypass compressor, and integrated cascade all
CO2 system with gas bypass compressor. The weather conditions of London, UK, and Athens, Greece, were
used for the modelling of energy consumption and environmental impacts to represent moderate and
warm climatic conditions respectively. The control strategies for the refrigeration systems were derived
from experimental tests in the laboratory on a conventional booster refrigeration system. The results
from the analysis showed that the CO2 booster system with gas bypass compressor can provide best performance with 5.0% energy savings for the warm climate and 3.65% for the moderate climate, followed by
the integrated cascade all CO2 system with gas bypass compressor, with 3.6% and 2.1% savings over the
reference system for the warm and moderate climates respectively.This study was supported by the Research Councils UK Energy
programme, Grant No: EP/K011820/1 and GEA Searle, now Kevlion.
The authors wish to acknowledge the cash and in-kind contributions
of these organisations as well as the support received from
Brunel University London and the RCUK National Centre for Sustainable
Energy use in Food Chains (CSEF)
