Demand Coverage and Energy Savings by Combined CO2 Refrigeration System and HVAC in Supermarkets

Transcritical CO2 refrigeration systems for supermarkets are more and more integrated to DHW production, space cooling & heating. In CO2 integrated solutions, the thermal loads of supermarket buildings are fully covered by the refrigeration system, but advantages in terms of total investment and running costs need to be carefully estimated. They are strongly dependent on several factors among which the quality of the building envelope, the climate, the ratio between HVAC demand and the refrigeration load. A model based on TRNSYS and in-house types, validated with field data from a fully instrumented plant in a supermarket located in Northern Italy, is used to investigate the integration as a function of the thermal loads. The size of the refrigeration unit is kept constant, four different sales area and six climate zones are considered. The full coverage of space cooling by the CRU is reached on the whole Italian territory, whereas the coverage of DHW production and space heating is guaranteed up to 90% and 83% respectively in the worst case and up to 99.3% and 100% in the most favourable case.