Heat Pump Methods
A heat pump works simply by moving the heat energy from one place to another. Your fridge works on the same principle.
Ground Source Heat Pumps
By using the same process the Ground Source Heating System removes heat stored in the earth and transfers it into your home. The sun naturally replenishes the heat removed from the ground. This energy source is renewable, inexhaustible, free and cannot be taxed. It transfers the energy from the ground around your house through a series of loops of pipe filled with a thermal liquid, and buried in trenches. The liquid is circulated, absorbing the heat in the ground and transferring this energy back to the house. As the system performance is unaffected by air temperature, efficiency is superior to the air source alternative.
How is the heat transferred from my garden into my home?
The earth has the ability to absorb and store heat from the sun. This heat is extracted from the earth using a ground loop. The ground loop is a continuous closed loop of special pipe buried in your garden. Water and glycol is circulated through the buried pipes where it absorbs heat from the surrounding earth. The ground loop is connected to a heat pump inside your home that takes heat out of the circulating water and transfers it into your heating circuit.
How are the loops installed?
The loops are either buried in trenches at a depth of 1 – 2 meters or installed in bore holes. Each method is as efficient as the other. Available space determines which method is used.
1. The brine solution (glycol/water) circulating in the ground loop picks up warmth from the earth and transfers it to the Heat Pump.
2. This warmth evaporates the refrigerant circulating in the Heat Pump, causing a gas.
3. In the compressor, this gas is compressed, creating heat.
4. The heat is conveyed into the house’s heating and hot water system.
5. The pressure of the gas is reduced via an expansion valve and the refrigerant turns into a liquid form ready for the next cycle
Water Source Heat Pumps
Working on the same principle as Ground Source Heat Pumps system, energy is extracted from a lake, river or borehole and transferred to the heat pump.
Water is an ideal medium for supplying energy. Loops can be laid on the bottom of a lake, river or large pond, or water can be pumped directly to a heat exchanger which extracts the energy, returning the water to its source. Water source systems offer the best efficiencies as the energy in the water is constantly replenished.
Air Source Heat Pumps
Thermal energy is extracted from the air, using a fan which passes air over a collector plate. The system is still effective at -20°C and is used extensively in Northern Europe.
Take advantage of the energy in the air all around us to provide all your heating and hot water. These systems require no ground loops, and energy is extracted directly from the air by the external heat pump.
At low ambient temperatures they do work harder than the ground source alternative, with lower efficiencies, but still well in excess of any fossil fuel boiler. Air source systems are ideal in new build or retrofit situations, where space or budget may be issues. They can be linked to traditional boiler systems to provide greater heating capacity.