Ground Source Heat Pump and Solar Thermal Installation

Introduction
The property was a 4 bedroom detached home in a small village in rural Warwickshire built in the 1990’s. Heat and hot water have been provided from an LPG boiler which was in need of replacement and the clients were concerned about the increasing costs of LPG. After assessment of energy needs and discussion of the alternatives options available the clients decided on a Ground Source Heat Pump with Solar Thermal for supplementary hot water heating, the solar panel being placed on the South facing roof at the front of the property.

Suitability, System sizing and Design

The property was reasonably well insulated with double glazing throughout, the only upgrade required was an increase thickness of loft insulation. The garden was 14m wide and over 80m long mostly laid to lawn which would be adequate for up to 3 ground source trenches. A heat loss calculation was carried out using the RdSAP method which identified the required heat pump size as 11Kw output. Considering the size of the property a separate 215 litre hot water tank was recommended. The locations for the heat pump and hot water tank were identified in the garage close to the existing site of the LPG boiler. The positions of the trenches, manifold and feed and return pipes were established to avoid the play area and shed in the garden. The feed and return and pump station locations were established for the Solar Thermal utilising a disused chimney.
Trench LayoutTrench Layout
3D Schematic
Installation The first stage of installation was to complete the groundworks including the trenches, manifold and feed and return to the garage.
Empty TrenchSlinky Inspection Chamber
Then the Heat Pump and Hot water tank were located, the collector feed and return connected to the heat pump, heat pump connected to tank and heat pump and tank connected to the property heating and hot water systems.
Tank Valves Heat Pump Valves Heat Pump & Tank
Finally the Solar Thermal system was installed.
Running the system The clients have been very pleased with the way the property is heated with the Heat pump, running costs over the 2008/09 winter period were less than half when compared to recent, and more mild, winters. From March to June 2009 the Heat Pump has been hardly used to heat hot water as this is being adequately achieved with the Solar Thermal, and has only been used occasionally to provide heating to the property.