Abstract

In the supermarket refrigeration industry, the natural refrigerant R744 (CO2) has been designated as a long-term solution to mitigate HFC refrigerants' global warming. In this study, booster (BB) and parallel compression (BP) configurations were assessed through a detailed and novel energetic modelling, which includes a semi-empirical "four-parameter" for reciprocating and scroll compressor models and a one-zone model for the gas cooler, and a three zones model for the condenser. Model validation showed a mean deviation of 4.23% against reference values. The COP of the BP configuration was 14% higher than BB, for ambient temperatures between 0 degrees C and 35 degrees C. This study presents for the first time, the simulation of transcritical systems with R744 throughout out different locations in Chile. Simulation results of fourteen Chilean cities showed that the BP system allows reducing the annual energy consumption between 4% for very cold climates and 12% for desert regions. An economic analysis revealed that only in most desert and warm climates (Arica, Antofagasta and Santiago), the differential capital expenditures of the BP system over the BB were recovered within 20 years with the operational expenditure savings. For the rest of the evaluated cities, the BB system is a more profitable solution than BP. The study aims to support the introduction of refrigeration system with R744 in Chilean supermarkets.