Integrated CO2 refrigeration and AC unit for hot climates.

An integrated refrigeration and AC system with CO2 as the only working fluid for use in very hot climates (+45 °C) has been designed, modelled and simulated in Dymola. Based on the simulation results, its feasibility is proven. The system can achieve 3 kW of cooling capacity at the low evaporation temperature level of -28.6 °C, 10 kW at the medium temperature level (-3.2 °C) and 20 kW for AC at an evaporation temperature of +12.6 °C. The use of ejectors is essential for the system performance at these extreme ambient temperatures, and enables an, until now, impossible application for the natural, environmentally friendly refrigerant CO2. The CO2 system achieves a similar performance compared to existing solutions applying synthetic refrigerants with high GWP and ODP, which are typically applied nowadays in high ambient temperature regions.