Heat Pumps

OutdoorSo, what is a Heat Pump?

A heat pump is a heating system which harnesses energy from free renewable sources outside the building, for heating your house and producing your hot water. A heat pump uses electricity to run a compressor which draws heat from a low temperature source, such as external air or the ground and then increases the temperature of this heat in order provide heating to the building's interior.

While conventional heating systems such as storage heaters and boilers cannot produce more heat than that contained in their fuel source, a heat pump can! Through the use of a special refrigerant and the unit's compressor, a heat pump will typically produce three to four units of heat for every unit of electricity consumed. This sounds complicated, right? But we are very familiar with a very similar technology already in all of our homes; the fridge! A fridge works in a very similar manner to an air-source heat pump, drawing in ambient air from behind the fridge and through the use of a compressor and a refrigerant, reduces the temperature to keep products cold. It works in reverse but basically, it's the same technology.

 

ecoGEO Compact frontCoefficient of Performance (COP)

You will often hear the term COP in terms of heat pumps. This refers to the efficiency of the heat pump. COP stands for Coefficient of Performance. Basically, it's a calculation of how much energy a heat pump can produce from a single unit of electricity. For example, a heat pump that produces a total of 4 units of heat from a single unit of electricity would have a COP of 4 (1 unit of electricity and 3 units generated by the heat pump). So as you can see, even though a heat pump uses electricity to increase the heat, it is actually very efficient and costs far less to produce heat per unit than raw electricity would.

 

Controls

Most heat pump systems have integrated heating controls, helping you to accurately match your space heating and hot water schedules to the working and living patterns in your home, so when heat and hot water are required, it is there; and when it is not required, it is turned off. Using the heating controls in your heat pump system will typically reduce your energy usage by up to 20%. Source: SEAI.

Hot water

Most heat pump systems can also produce hot water for domestic use. As the temperatures required for DHW are much higher than for space heating, this element of heating does not operate as efficiently but can still be less than half the price of heating with electricity. A domestic hot water cylinder is often included with the heatpump as part of the internal unit, such as within the one across.

 

Types of Heat Pump systems

Different types of heat pump systems draw their heat from different sources. Such sources could be air, water or the ground. The heat that's generated is then distributed around the building via radiators, underfloor heating or warm air units (fans). It is important to note that heat pump systems will only work efficiently when working to lower temperatures than conventional boiler systems. Therefore, our homes need to be well insulated and/or the surface area of our heat emitters needs to be greater than normal. Heat pump systems work best therefore with low temperature distribution systems such as underfloor heating or special low temperature radiators. Heat pump systems (excluding those providing warm air to the home), can also supply most of the hot water needed for baths, showers and sinks but it is important to realise that this will not be at the same efficiency as for space heating as the heat pump is being forced to increase the water temperature much further.

OutdoorAir Source Heat Pumps:

As the name suggests, these heat pumps take the ambient heat from air sources. The air source can vary as can where the heat is sent to...

  1. Air to water heat pump systems are the most popular choice of air source heat pump system, especially when retrofitting. They extract heat from the external air, typically using an outside unit such as that shown across. These heat pump systems do not require underground piping (outside) to source heat and so can be cheaper and easier to install compared to ground source heat pump systems. Heat is then distributed through wet systems such as radiators and underfloor heating and these units can also produce hot water.
  2. Exhaust-air to water heat pump systems are similar to air to water but these units extract and recover heat from inside the dwelling rather than outside. The also include mechanical extract ventilation which is used to ventilate the building so they draw in fresh air from outside for this purpose. These are generally very small units and are suitable for apartments or very small houses.
  3. Air to air heat pump systems extract air from external air, similar to that of an air to water sytems. In this case however, the heat is distributed through air units, ie. warm air is gently blown into rooms via a network of ducting. Air to air heat pump systems do not provide hot water and are generally not as popular, especially here in Ireland.

Ground Source heat pumps are a relatively popular option for new builds in particular. These extract heat from the ground, through a network of underground piping (teh collector) outside the building. The ground collector can be laid out horizontally at a shallow depth below the surface or else vertically to a greater depth (borehole). As there is generally greater heat available from the ground in winter time (when we need most of our heat), a ground source heat pump is more efficient than an air source but it is more expensive to install due to the much larger collector and excavation work that's required. 

Water Source heat pumps are almost identical to ground source heat pumps, except that the collectors are laid in a water source such as a river bed or a lake. This is ideal if the building to be heated is near a water source as the installation is much easier.

Important note: Regardless of the type of heat pump system you choose, it is important to understand that you will need leave your heat pump switched on for long periods of time to make sure that it performs well and operates most economically. This is especially true when used in conjunction with underfloor heating as this is slow to get up to temperature from a cold start. It is also extremely important that the correct heat pump is selected and that it is installed and commissioned by competent professionals. There are far too many cases of heat pumps being installed badly or incorrectly specified, resulting in huge electricity bills for the user.

Warning: As heat pumps are an emerging technology in Ireland, there are many new companies entering the market with heat pumps and many "installers" setting up to fit them, many of whom are of questionable quality and backgrounds respectively. Heat pumps can be a fantastic option for your home but your home must be suitable, the heat pump must be correctly selected and it must be installed and commissioned correctly.

Call our sales team now on (098) 42699 or email us at info@comfortsolutions.ie for an estimate on a system for your home.