The Heat Pump Experts

Ground Source Heat Pumps

How Ground Source Heat Pumps work

Ground source heat pumps systems which extract heat energy from the ground or groundwater offer exceptionally high levels of efficiency, achieving significant reductions in CO2 emissions and energy bills.

There are a number of ways in which heat can be extracted and we are able to offer a full range of products and services, to ensure that you get the best solution for the location, building requirements and budget. These include energy piles and open loop or closed loop systems, with the option of extracting heat from either the ground or a water source.

At the forefront of geothermal system design and with more than 1,300 ground source heating and cooling systems installed in the UK, we are able to offer expert system design. Our in-house Drilling & Groundworks division provides a full design and installation service, including the incorporation of geothermal pipes into the structural piles of new build properties.

Benefits

The main benefits of Air and Ground Source Heat Pumps can be summarised as follows:

  • They save money. An Air or Ground Source Heat Pump can help to achieve significant fuel cost savings compared to direct electric heating systems (e.g. storage heating), gas boilers, oil boilers and some renewable energy systems, such as biomass boilers. Additionally, the Government has introduced the Renewable Heat Incentive for owners of heat pumps. Commercial building owners will benefit from a subsidy from September 2011 and residential building owners from October 2012 (tbc). This subsidy will significantly shorten the 'pay-back' time, making a heat pump an even more attractive option, producing a return of about 12% on the initial investment.
  • They are an eco-friendly alternative to oil, gas and LPG. Although they require electricity to operate, the output generated is around 2.9 to 4.0 times the power input (known as the CoP or Co-efficient of Performance). If a renewable source of electricity is used, for example, photovoltaic panels, they are completely carbon neutral - and you would then not only benefit from the tariff payment for the heat pump, you would also benefit from the new Feed-in Tariff scheme on the PV panels.
    • To secure the Renewable Heat Incentive you must have a heating COP > 2.9
    • Geothermal International designed systems are expected to achieve COP's as follows:
      • Heating only up to 3.8
      • Heating and Cooling system - Heating only up to 4.8
      • Heating and Cooling system - Cooling only up to 5.8
  • They don't require any fuel storage space, unlike oil and LPG which require large storage tanks, and biomass boilers which require wood/pellet storage. There is also the peace of mind that there is no need to store large volumes of combustible fuel on the premises. They do not require flueing as there are no harmful emissions.
  • Low maintenance. The basic mechanism is similar to a refrigerator, with few moving parts and few things that can go wrong - all you need to do is keep the unit clear of leaves and debris. The most costly part in the unit is the compressor and you have the option to extend your warranty if you would like the reassurance that all parts and labour are covered in the longer term.

How They Work

How Ground Source Heat Pumps work

Heat Pumps operate in a similar way to a refrigerator – but in reverse. Heating and cooling are achieved by moving a refrigerant through various indoor and outdoor coils and components. A compressor, condenser, expansion valve and evaporator are used to change the state of refrigerant from a liquid to hot gas and from a gas to cold liquid.

The main stages of the process are as follows:

  • Liquid refrigerant passes through the outdoor evaporator coils at a low temperature.
  • Liquid from the ground loop enters the unit and heat is transferred from this liquid to the refrigerant. As a result, the refrigerant boils and becomes vapour.
  • The vapour is drawn into the compressor, where the temperature of the vapour is increased to over 100 degrees.
  • The vapour then enters the condenser heat exchanger and heat from the vapour is transferred across the coils. As the vapour cools it condenses back to a liquid, which releases considerable latent heat to the air passing over the heat exchanger.
  • The refrigerant, which is now a very cold liquid at high pressure, passes through an expansion valve, which reduces the pressure so that the cold liquid can re-enter the evaporator and begin the cycle again.

At stage 4, the heat is transferred to the buildings heating, cooling and hot water systems.

Drilling & Groundworks

Geothermal International's specialist in-house Drilling division is at the forefront of heat pump installation and is able to undertake all aspects of ground preparation for our clients. We offer the full range of collectors and will design the system that fits best with the available land or water source, the local geology and the heating requirements. The different types of collector are described below. For new build projects, energy piles can be incorporated into the building design. With some of the heat pump pipes incorporated into the piles the need for further drilling and groundwork is significantly reduced.

Closed vertical loop

The ideal choice when available land surface is limited. Drilling equipment is used to bore small-diameter holes from 50m to 150m deep.

Closed vertical loop

Open loops

Open loop systems utilise ground water as a direct energy source. In ideal conditions, an open loop application can be the most economical type of geothermal system.

Open loops

Horizontal loop

Often considered when adequate land surface is available. Pipes are place in trenches in length that range from 30m to 120m.

Horizontal loop

Pond (lake) loops

These are very economical to install when a body of water is available because excavation costs are virtually eliminated. Coils of pipe are simply placed on the bottom of the pond or lake.

Pond (lake) loops

System Design

The key to achieving optimum levels of performance and efficiency lies in the design of the heat pump system. Geothermal International has been designing ground source heat pumps systems longer than anyone in the UK and has designed and installed the largest closed loop system in the UK (with 150 bore holes, each 98m deep) and the largest open loop system in the world (providing up to 5MW of heating & cooling).

In general, the design process is carried out as follows:

Feasibility Study & Discussion Document

Our design service begins with an initial feasibility study, We will ask you to provide the postcode of the property/development, an outline of the heating and cooling loads and site plans if they are available. Using this information, along with geological information for the location, a member of our technical team will prepare a discussion document. It will include outline installation costs, estimated carbon run costs and estimated savings.

Site Visit

This provides the opportunity to discuss the project in detail and for the engineer to gain a full understanding of the client's requirements.

System Design

We have developed our own ground loop design technology. This bespoke software provides greater levels of accuracy and flexibility than any other in the market place. For large scale installations the detailed design document will include all aspects of the external works, plant room layouts and the interface with the internal heating distribution.

Once the system has been designed and approved, we can hand the drawings over to your approved installer or we can undertake the full installation process. Geothermal International will be responsible for commissioning the system.

After Sales Service

Our fully trained maintenance and service engineers cover the whole of the UK and provide our customers with expert on-site supervision, technical diagnostics, repair services and planned maintenance capability. Field technicians, field engineers and in-house engineering support teams work closely with our clients to develop specific solutions for individual projects. Our aim is to provide our customers with the quality service and support required for maintaining high reliability and long term use of their equipment. Our services include:

  • Repairs
  • Bespoke service agreements
  • Spare parts packages
  • Equipment upgrades
  • Control Software
  • Supervisory Management Systems

Product Warranties

Geothermal International offers a wide range of warranty & maintenance options. Our standard warranty is for 2 years parts & labour, from the date of supply. At the end of this period, extended warranties are available, to ensure peace of mind over the lifetime of the product.

Heat pumps use similar technology to a refrigerator, so servicing and maintenance needs are minimal. However, low level maintenance to check electrical connections, clean filters, check fuses etc is recommended, to ensure that the appliance runs without problems for many years. Annual servicing and operational checks can be built into extended warranty agreements. Extended warranties also cover the equipment in case of failure of a major component, such as the compressor.

An extended 2 year warranty package typically includes:

  • Annual service checks to ensure the appliance continues to function correctly & efficiently
  • Annual parts & labour cover, in the event of any breakdown due to mechanical or electrical failure of any component in the appliance (not caused by damage, incorrect use or application of the appliance and as long as it has been continually maintained by us)

Bespoke maintenance and warranty packages can also be arranged.

Terms & conditions apply. Please Contact us for further details.