National Installer Magazine Feature


Posted by Sam | 14th November 2016

hybrid heat pump case study

Featured in Daikin's 'The Installers Guide: Heat Pumps' - November 2016

Article - A barn-storming opportunity

'A former barn - in a Northamptonshire village - is being extensively modernised. In addition to remodelling the interior layout, the owners are working to bring the FL-shaped, 250m² building up to current housing standards.

When the family moved from Hackney, London, to their new home in the village near Wellingborough, the inherited electric storage heaters which proved inefficient and expensive to run. "We moved in a January and ran the heaters for a month. They cost us a fortune so we quickly became reliant on log fires for warmth," says the owner. "We were determined to find a better solution by the next winter. Of we'd had mains gas, we might have gone for a conventional has boiler and radiators. But the cost of connecting to the gas grid would have been prohibitive so we started looking at heat pump instead".

Plan B

The original plan was to install a pair of Daikin Altherma High Temperature heat pumps, but the power supply to the property was inadequate. He says: "We asked the electricity supplier to quote for upgrading the supply, but they took so long to respond that we chose the 8kW Daikin altherma LPG Hybrid instead". 

The system was installed just before last winter and the new technology is already a winner with the family of four, who are enjoying increased warmth from their new radiators, and cash benefits from the Government's Renewable Heat Incentive (RHI) - a total of £156.98 in the first two quarterly payments. 

The new system was calculated to reduce the barn's heating-related C02 emissions from 19.6 tonnes a year to just 5.8 tonnes. The Daikin Altherma Hybrid combines heat pump technology with a high-efficiency gas combi boiler to provide heating and hot water. As the home is off the gas network, the combi boiler piggybacks the newly-installed LPG supply to a gas range in the new, enlarged kitchen.

Zone system

Matthew Young, of Kettering-based Daikin D1+ installer Griffiths Air Conditioning, engineered the Daikin Altherma Hybrid solution, which unusually incorporates a hot water cylinder.

"As the building is effectively a long bungalow - with kitchen, utility room and family bathroom at one end and bedrooms with en-suite showers at the other - we installed the hybrid with multiple set-point control. The third-party hot water cylinder is set as one zone with a fixed 70ºC flow temperature. The heating circuit is set as a second zone, operating with a weather-dependant flow temperature (40-50ºC). There is a heating and DHW timer, and cylinder thermostat with an interlock preventing the heating circuit valve from opening when the system is supply the DHW cylinder. The combi boiler - part of the Hybrid's wall-hung indoor equipment - serves the showers, and supports the heat pump when necessary".

The installation was designed for annual hot water demand of 6,209kWh and heating demand of 39,856kWh. Heat loss was calculated as 15.2kW.

Winter Comfort

The owner says that while he, his wife and two children are more comfortable approaching another winter, they recognise that their house is probably not yet at peak efficiency as they are still working on their home improvements - including better insulation. They may also decide to review their hot water arrangements to take greater advantage of the Hybrid's efficiencies and reduce their carbon footprint still further.'

Published in Daikin's 'The Installer's guide: Heat pumps' - October 2016

For more information about Daikin's Hybrid heat pump system, contact Griffiths by Telephone on 01536 420666, via the website or by visiting their Energy Efficiency Centre showroom at 111 High Street in Burton Latimer between 9am and 5pm Monday to Friday.