Ground Source Heat Pumps

A ground source heat pump is used to extract heat from the ground & transfer the heat into your home. The heat is extracted by fluid inside a loop of pipe slowly being pumped around the loop, where it increases in temp by 3°C. This heat is then transferred to the house by the heat pump which delivers hot water at around 45°C.

A Ground source heat pump system consists of:

  • Ground loops (a network of pipes buried underground)
  • A heat pump at ground level (the pump consists of an evaporator, a compressor and a condenser)
  • A mixture of anti-freeze and water
  • A water cylinder

Heat energy is absorbed from the ground by an anti-freeze and water mixture which circulates in the ground loops. The cold mixture is pumped underground where it is heated and flows back to the heat pump in the building. The heat pump then transfers the fluid to a gas in a refrigerant by the evaporator, the gas is then compressed in the compressor causing the temperature to rise. The air source heat pump can increase the temperature from the ground by between 1.5 and 4 times - so if the ground temperature is 12°C, the output would be between 18 and 48°C. The condenser then transfers the heat from the hot gas to the central heating system. It can then be used to heat either the water in the cylinder, under floor pipes or radiators.

At ESP Energy we install a range of different Ground Source Heat Pumps from suppliers such as NIBE, IDM and Eco Forrest. These enables us to ensure that we find the right product for your project and budget.

Ground Source Heat Pumps are eligible for the Renewable Heat Incentive, this allows you to earn money from the government for using renewable technology.



What is a Ground Source Heat Pump?
A heat pump is a device, which transforms low-temperature energy to higher-temperature energy using the refrigeration cycle. A ground source heating system heat pump is three to four times as energy efficient as the most efficient gas or oil boiler. Instead of burning a fuel, and producing the associated emissions that contribute to global warming, they simply move heat that already exists.

How Efficient is a Ground Source Heat Pump?
Modern systems are very efficient. For each kilowatt of electricity used to run the heat pump, three to four kilowatts of heat can be delivered to the building. The efficiency of a GSHP installation is very dependent on the quality of the design and installation. The efficiency of the installation is improved by utilising solar recharge of the ground.

How are the loops installed?
The special ground loops are either buried in trenches at a depth of 1 - 2m or installed in bore holes that may be up to 90m deep. They can also be placed in lakes or ponds. Each method is as efficient as the other. Available space determines which method is used.

How much loop will I need in the ground?
That depends on the energy requirements of your building, where you are in the country and the type of ground you have. This will come from the specialised design work we will carry out as part of your project. However, the larger the building generally means more energy is required thus more loop in the ground. Air source heat pumps do not need and loop system in the ground.

What plumbing do I need and can I keep my existing radiators?
You can use under-floor heating and radiators for heat distribution in your home. Ideally for maximum benefit and efficiency, a heat pump works best with under-floor heating, but oversized or extra radiators are also a practical option.

Can ground source heat pumps be installed in older buildings?
Yes, but your building must be well insulated for you to gain most benefit. The cost of a system is directly related to the heat losses, which will generally be higher in older buildings. Money spent on upgrading insulation levels can save a considerable amount on the capital cost of a ground source heat pump system.

Will it heat a building on the coldest winter day?
Yes it will. Thousands of these systems have been installed for many years in some of the most northern parts of Scandinavia where the winters are very hard and long. The key is the design and specification process so the system provides enough energy for the application.

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