Using excess heat to provide free hot water

Installation of City Multi 2-pipe VRF heat recovery system coupled to the unique PQFY heat pump boiler, provided fully controllable air conditioning, and free hot water for the swimming pool.

The owners of a 4-bedroomed house in Kent have been using a unique new boiler to provide free heating for their swimming pool, whilst enjoying fully controllable air conditioning to provide year-round comfort cooling and heating.

When the house, which stands in the grounds of an Equestrian Centre near Dartford, Kent, was being refurbished the owners decided to install air conditioning in the bedrooms and an annexe containing a small gymnasium.

With rising summer temperatures, especially in the South East of England, the owners wanted a system that would provide comfort cooling particularly at night, but which would also be versatile enough to cope with Britain's variable temperatures by being able to switch to heating.

"Added to this was the need to replace the heating source for the property's outdoor swimming pool, which had previously been heated by a wood-burning boiler," explained Andy Hubble of H and H Services , who installed the Mitsubishi Electric equipment.

This wood-burning boiler had proven expensive to run, troublesome to maintain and made it very difficult to control and regulate the temperature of the pool.

Whilst summer cooling was the primary driver for the installation, the owners also wanted to control energy costs and find an alternative to the high maintenance pool heating system.

With the installation of a City Multi 2-pipe VRF heat recovery system coupled to the unique PQFY heat pump boiler, the owners now have the best of both worlds - fully controllable air conditioning, and free hot water for the swimming pool.

The PQFY heat pump boiler uses the vapour compression cycle of the air conditioning system to raise the water temperature of the outside pool to a comfortable level.

Instead of simply discharging the heat from the refrigerant to the air as in a conventional split type air conditioner, the hot gas pipe in the PQFY runs through the water piping in a unique tube-in-tube coaxial system that extracts the heat from the refrigerant cycle and transfers it directly to the water.

This effectively provides free hot water for the swimming pool and is far more fuel efficient than the wood-burning stove, helping to reduce the running costs of the swimming pool by more than half.

It is also around four times better than the most efficient type of conventional gas boiler on a kW / kW basis, leading to a substantial reduction in CO2 emissions.

"Exact control of the swimming pool temperature is also achieved by the inverter-driven compressor which only consumes as much energy as needed to continually match the pool heating demand," added Andy Hubble.

In the winter, the air conditioning that supplied the much necessary summer cooling, is switched to provide heating to the house and gym.

The swimming pool is covered for the winter months and thus has a very small heating requirement.

The heat produced by the City Multi system to supply the house has reduced the heating power consumption by 50% compared to the previous existing radiators and boiler combination.

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