Development and Evaluation of a Reversible CO₂ Residential Air Conditioning System Compared to State-of-the-Art R410A Unit

A reversible CO₂ prototype RAC split unit system has been designed, built and installed in two calorimetric test chambers. The unit is based on the Lorentzen cycle with a receiver and a suction line heat exchanger. Both the indoor and the outdoor heat exchangers have tube-in-fin design. The hermetic compressor has two compression stages and is inverter driven. In the heat pump mode the CO₂ prototype unit can either operate as a conventional one-stage circuit or as a two-stage system. In the air-condition mode, there is an option for cooling of the compressor first stage discharge gas. Experimental tests are under preparation. Realistic simulations have been carried out with the advanced in-house simulation program CSIM using input data for all components of the prototype. A state of the art inverter driven R410A split unit has been tested experimentally as a baseline unit. Obtained results have been compared to simulation results for the CO₂ prototype.