The UK’s first Daikin Altherma hybrid heat pump has been installed at a family home in Wigan – where independent monitoring has revealed impressive performance figures and significant running cost benefits.
The system combines a gas condensing combi boiler and an air-to-water heat pump to create an energy efficient domestic heating and hot water system, said to be ideal for gas boiler replacement.
After a recent addition to the family, James Jennings and his wife decided their existing gas combi boiler needed upgrading to ensure the house was warm enough all of the time, not just at certain times of the day. James was confident that by choosing the new hybrid system, he could keep the house warm without increasing his fuel bills.
Monitoring through the nine months to 31 March 2015 showed that the heat pump was able to provide 50% of space heating. Primary energy efficiency was 105%, and the Seasonal Performance Factor was 3.6. The renewable energy produced by the heat pump equated to a Renewable Heat Incentive payment of £307.
Daikin’s system has two settings for heating: ‘ecological’ or ‘economical’. In the ecological setting, the system is set to limit carbon emission rates, potentially saving the Jennings family around one ton of carbon every year. In the economical setting, the smart controller automatically searches for the most economical operating conditions for the lowest running costs, based on electricity and gas prices, heat pump efficiency, heat load and required leaving water temperature.
At higher outdoor temperatures, when the heat pump has sufficient capacity to cover the heat load, it will operate alone. As temperatures fall, the boiler starts to support the heat pump in hybrid mode, only taking over on the coldest days, when using the heat pump becomes less cost efficient.
The system comprises a heat pump and boiler working in series, rather than parallel as for most bi-valent systems. This means that in hybrid mode, heating water is pre-heated by the more efficient heat pump, reducing the energy consumed by the boiler. In ‘economical’ mode up to 35% higher heating efficiencies can be achieved over a gas condensing boiler alone, saving a substantial amount of energy, with lower fuel bills as a result.
A room-by-room heat loss calculation was carried out prior to installation, to ensure that an adequately sized heating system was installed and to ascertain whether or not the existing radiators could be retained. The design flow temperature of water through the system is up to 60 °C when the temperature is -2.2°C outside, which means that the Jennings’ radiators and pipework did not need to be replaced. When the external temperature reaches 15°C, the design flow temperature is 35°C. Using the MCS guidelines, the heat loss for the property was estimated to be 9kW at -2.2°C
A local gas engineer installed the appliance and James, who is also a registered gas engineer, commissioned the hybrid system. The indoor unit is about the same size as a standard boiler and so fitted easily into the space of the original gas boiler. The indoor heat pump module was mounted onto a wall bracket, with the gas boiler fitted onto the front and fixed to it. All the connections were easily accessible, allowing straightforward installation and commissioning.
Refrigerant pipework to the 5kW outdoor heat pump unit was installed and commissioned by a qualified F-gas installer. The outdoor unit was fitted on the back wall between the ground and first floor to avoid taking up space in the garden.
The Jennings now have a constant supply of heat, making their home comfortable and warm, with the added benefit that they will see significant savings.
James said: “It was a pleasure to install the UK’s first Daikin Altherma hybrid heat pump and great that we will be able to guard against rising fuel bills.”
