The system uses tried and tested equipment, namely a well respected Intergas boiler and the Daikin Altherma LT heat pump and, according to Daikin, is up to 130% efficient. The hybrid is aimed squarely at properties using gas or LPG boilers and has the added advantage that households will not need to replace their radiators or cylinders if they install it. This has been a point of confusion in the heat pump market which this product addresses. The Daikin hybrid can also work with underfloor heating and heat pump convectors.
Distressed purchase market
Daikin's hybrid is very much aimed at 'on-gas' properties of which there are far more in the UK than there are properties of the gas grid. However, due to cost of the complete solution (~£6,000), the hybrid is going to appeal to group of customers that are likely to be 'early adopters' of energy efficiency products and who have strong environmental concerns until such time as Daikin can make economies of scale when heat pump installation increase substantially in the UK.
Four modes of operation
The third mode kicks in when the ambient temperature drops further at which point the gas boiler becomes the predominant heating element as the heat pump becomes less economical to run. The fourth mode uses the boiler only for heating and hot water when the temperature is too low to run the heat pump efficiently.
Nevertheless, the Daikin Altherma LT heat pump boasts some remarkable efficiency credentials. The 5 kW heat model boasts a COP of between 3.58 and 5.04, with the 8 kW version achieving COPs between 3.42 and 4.45. Daikin provided an example of an 110 year old, solid wall, 140m2 mid-terraced house which has double glazing and a loft conversion which had an old combi boiler which needed replacing. Furthermore, the house had a design heat load of 9kW at -6 degrees C and had a total energy demand for heating of around 18,000 kWh.
After installing and running the hybrid heat pump into the house, the heat pump provided 13,060 kWh of space heating It also achieved a "measured seasonal efficiency of 126% for space heating, as well as 120% for combined space heating and hot water". When using the heat pump alone for heating, the system managed a sCOP of 340%. When in hybrid mode (i.e.. using the heat pump and gas in combination), the system accomplished a sCOP of 177%. When using only the gas boiler, the result was a sCOP of 120%.
Eligible for RHI
The Daikin Altherma Hybrid heat pump appears to be a sensible idea for helping householders on the gas grid become more energy efficient and it has a potentially wide market available to it. The raw cost of it may put some homeowners off having it installed, so installers will need to be careful how they present this product as a solution to their customers and make sure they sell the concept to the section of customers to whom Daikin believes this will appeal.