Air-Conditioning Cooling and Heat Recovery for R-744 systems

The presentation goes into the detail of how Air-conditioning heating and cooling can be incorporated from a R-744 refrigeration pack for the small convenience store market, avoiding the need for a separate R32 Air conditioning system.

The presentation will show schematic diagrams of a R-744 system, demonstrating how the excess heat can be recovered and how to use R-744 for Air conditioning cooling via the intermediate pressure of the R-744 refrigeration unit. The presentation will also explain how the heat that can be recovered changes significantly when the R-744 hot gas goes sub critical. We will then explain how the Marstair R-744 units which are 4-pipe heating and cooling can be used as terminal units to supply both the heating and cooling needs within a single terminal unit. We will show the various unit options available including wall mounted, concealed ducted fan coils and cassettes. We also detail options for Direct R-744 hot gas at 120 Bar Max working pressure or LPHW hot water. The presentation will also give information on controls and valve options. We detail how R-744 air-conditioning cooling evaporators are selected using evaporating temperature and return air temperature. How hot gas heat recovery units are selected for both sub critical applications using condensing temperature and return air temperature and trans-critical applications using R-744 gas pressure with inlet and outlet R-744 temperatures.

Finally, we will give some case studies showing examples of R-744 Air conditioning applications.