A ground source heat pump (aka ground-to-water heat pump) transfers geothermal heat from the ground outside your home to heat your radiators or underfloor heating. It can also heat water stored in a hot water cylinder for your hot taps and showers. The constant year-round temperature of the ground is approximately 8-12 degrees centigrade (depending on location) and so provides a constant supply of energy which can be passed through a cycle of evaporation, compression, condensation and expansion and ultimately heat your home. The majority of ground source installations use a ground collector installed horizontally in trenches, if sufficient land is available this tends to be the most cost-effective method. The ground heat collector pipe can be installed in long lengths using a digger or trenching machine to bury pipe 1m deep and around 1m apart. Less digging is required if coils known as "slinkies" are used. These typically are installed in a trench 1m deep by 1m wide. The same area of ground is needed for a horizontal or slinky collector but as the slinkies work the ground harder these need to be further apart. Boreholes provide an excellent solution where space is limited but are more expensive to drill. These can be anything from 60 to 150m deep and at least 6m apart. Ground Source Heat Pumps collect heat from the ground using a network of pipes buried either horizontally in trenches or vertically in boreholes.
ADVANTAGES OF GROUND SOURCE HEAT PUMPS - Modern GSHPs are virtually silent - Heat collector is buried, so hidden from sight and generally qualify for permitted development rights - No flues, chimneys or fuel deliveries needed - Most energy efficient form of heating – up to 600% - Zero carbon heating if using green electricity - Can provide all heating and hot water as well as cooling - Eligible for BUS grant and tax benefits - Constant and inexhaustible – long life system 50 years +
DISADVANTAGES OF GROUND SOURCE HEAT PUMPS - Higher initial installation costs - Efficiency affected by soil type - Digging of trenches / borehole can make your property temporarily messy but then becomes invisible once the grass has grown back or landscaping is finished- For effective performance, a ground source heat pump needs designing as a system, combining the heat demand of the building, the heat pump and the underlying geology which must be done by a competent specialist
How reliable are heat pumps?
Heat pumps have been widely used in Europe and North America for decades. Because the refrigeration cycle is a tried and tested technology they tend to be extremely reliable. However, in order to ensure they continue to run as reliably and as efficiently as possible we always recommend servicing them annually, just as you would a conventional boiler.
Why are heat pumps becoming more commonly used?
Traditionally the UK had plentiful supplies of fossil fuels; oil and gas from the North Sea and extensive coal workings. However, there are two main issues with this: - Burning fossil fuels releases climate changing carbon dioxide that had previously been locked away underground.- Energy prices are rapidly rising as the UK increasingly imports oil and gas from abroad.
What is the temperature of the hot water produced?
Heat pumps are very efficient at heating water to around 40 degrees celsius. As such they are ideal partners for underfloor heating systems which typically require a flow temperature of the same. Heat pumps work less efficiently when heating water to higher temperatures and as required by the direct hot water in your home, but they will still readily maintain a hot water cylinder to a temperature of around 55 degrees celsius which is hotter than would be required for a bath or shower. Heat pumps also automatically run periodic legionella cycles to ensure that any bacteria that might still survive at 55 degrees are definitely removed.
How much maintenance is required for a heat pump?
The heat pump itself is a sealed system and doesn't produce any waste gases, ash or moisture. It is recommended that the heat pump be serviced annually by an accredited company to check things like the filters, strainers, fluid quality, refrigerant, temperatures and that the system is still operating as efficiently as expected. In rural settings, mice can be an issue, eating lagging or electrics and as you’d expect with air source systems, it is important to ensure that the external fan unit is clean and free of leaves or other such waste or vegetation that could impede the flow of air through it, particularly in autumn as leaves are falling and the system is starting to work harder as the colder weather arrives.
The project: A rural 3-bed holiday home used for holidays and weekend escapes. Due to recent rising electricity costs, the couple were keen to …
The installation of: 2 Ground Source Heat Pump System (GSHP), underfloor heating and PV array The project: This is a charming conversion of …
The installation of a 180kW Stiebel ground source heat pump system with bore hole heat collector. The project: Complex of several blocks of …
