Heat recovery makes CO2 trans-critical solutions more competitive. The heat recovery can be achieved in one stage or in two stages by using two desuperheaters in serial, because of the CO2 temperature profile.

An EES model was developed in order to analyze what are the best operating conditions for an ice rink refrigeration system in 3 different heat recovery scenarios, respecting real desuperheater properties. The scenarios are one stage which provides water heating from 20 ºC to 60 ºC, one stage with 20 ºC to 70 ºC and two stage with 20 ºC to 70 ºC.

According to simulated results the refrigeration system can be more efficient if it operates under specific discharge pressure and subcooling. An optimum control strategy has been designed according to each scenario and the heat demand.

Result show that the power consumption in the two-stage solution is 10% lower than the one stage scenario from 20 ºC to 60 ºC. The two-stage solution provides higher quality energy by consuming less power.