Heat pump can provide hot water at up to 90°C
MHI’s Q-Ton air-to-water heat pump uses CO2 as the refrigerant and can heat sanitary hot water at up to 90°C. These 30 kW units can achieve a COP of 4.3 with water on/off at 12/65°C and ambient air at 16°C, falling to 4.2 with water on/off of 5/65°C and ambient of 7°C. With an ambient of -25°C, the COP is still close to 2.
Q-Ton heat pumps have a 2-stage combined scroll-rotary compressor. Up to 16 units can be connected in a modular configuration to give 480 kW and connected to 4000 l of hot-water storage. Central control is provided by MHI’s Superlink II communications network and BMS interface if required.
Running costs are said to be 58% lower than a gas-fired boiler, and there is no need to top up with gas or electric appliances.