Simulations and field tests of a CO2 refrigerating plant for commercial refrigeration.

During the refurbishment of a supermarket in northern Italy, the HFC refrigeration plant has been replaced by a new CO2 transcritical system. A deep synergy has been favoured with the HVAC system, by allowing mutual heat exchanges at various temperature levels. Simulations have been performed at the design stage, with a TRNSYS based tool and in-house types for the refrigerating unit and the display cabinets. The plant was fully instrumented, and the availability of measured data on the new system allowed assessing its actual performance and validating the model. It was then possible to investigate the effectiveness of the heat recovery solutions applied, and to optimize their control rules.