The Background
A Greener Alternative were appointed by the client to design a heating system at their rural property in West Sussex that would replace an ageing oil boiler and utilise a more sustainable heating system for both their house and garage annexe.
Through conversations with the client and understanding their vision it was decided that a ground source heat pump with geothermal boreholes would be the most suitable solution to meet the needs of the property.
The Solution
Two NIBE F1145-12kW ground source heat pumps were specified to take care of all the heating and hot water requirements for the house and a single NIBE F1245R-6kW ground source heat pump with built-in hot water cylinder for the annexe. The units are all sited in the large garage beneath the annex installed neatly at the back end to further utilise space.
With an adjacent paddock forming the ideal site for the heat pumps ground collectors a series of six geothermal boreholes were drilled vertically down each hole between 100-150 metres in depth. The boreholes are connected to a central manifold and services run back to the property using pre-insulated header pipe.
With the boreholes drilled, connected and services run back to the garage where the heat pumps are sited there is now very little evidence that the boreholes and groundworks have even taken place. Now the borehole work is complete there is no need to access them in the future and all service access is made via the manifold.
The Result
The three NIBE heat pumps reside in the garage as shown below with the taller unit supplying heating and hot water to the annexe and the two smaller heat pumps working in tandem to provide for the main house.
The NIBE F1255-6kW unit feeding the annexe includes a built-in buffer tank and hot water cylinder which provides all the annexe requires by way of heating and hot water.
The NIBE F1155-12kW units utilise the buffer vessel sited to the right of the heat pump units to reduce cycling of the heating system and to further improve efficiencies. The heat pumps and buffer supply the heat pump hot water cylinder which is sited within the main house to take care of all the hot water needs for the home.
The Facts
Annual running cost of oil system: £2,820.00
Annual running cost of heat pump system: £1,760.00
Annual energy bill saving: £1,060.00
