Since several years carbon dioxide (CO2 - R-744) has been identified as one of the best alternatives to high GWP refrigerants in a number of market sectors, such as supermarkets and sanitary hot water heat pumps.
However, experts are sometime concerned about its use in larger industrial systems, with lower energy efficiency and lack of large scale R-744 trans-critical components being considered as main limiters in this sense, thus leaving anhydrous ammonia (NH3, R-717) as the preferred choice for larger duty applications.
And while ammonia is an excellent refrigerant from a thermodynamic standpoint, its application can be hampered by local government regulation and, sometimes, by its associated energy efficiency drawback. For instance, local ...