Heat Pumps
Introduction to Heat Pumps
Heat Pump technology is both an environmentally friendly and cost-effective way of heating your home. Heat energy is derived from 3 sources:
Heat pumps use much less energy than conventional heating systems, since they draw heat from the ground, water source, or the air. They are one of the most efficient ways to heat a home and provide hot water, not only saving energy and money, but also reducing air pollution. Heat pumps can help you to save up to 60-70% of your heating costs on an annual basis.
Ground Source Heat Pumps - General
Ground-Source Heat Pumps (GSHPs) make use of the natural warmth from the ground to heat your home. Heat pumps are installed under the ground - beneath the frost line - where the earth is at a constant temperature, approximately between 4-8 degrees Celsius. This energy is absorbed by a heat-exchanging coil, installed in a trench or borehole. This heat is upgraded to a higher, more useful temperature and circulated around the home.
With recent advances in heat pump technology, some of the heat pumps available through Enerfina are now capable of heating water up to 65° Celsius, and can be automatically programmed to increase the water temperature up to 70° Celsius once a week, as a precautionary health measure to destroy any build-up of bacteria within the system.
Minimal electricity is needed to operate the heat pump. A typical Ground Source Heat Pump will have a COP (Co-efficient of Performance) of 3.5 – 5.5, which means that each kW of electricity used to drive the heat pump, will generate between 3.5 – 5.5 kW of useable heat energy.
The opportunities for using Ground-source Heat Pumps in refurbishment are constrained by the land available to install a trench system or a borehole. However, they are growing in popularity and should be seriously considered as solutions for rural or suburban homes with large gardens. In the new build market, there are a number of property developments in the UK and Ireland which feature community based heat pump schemes as part of the development.
Ground Source Heat Pump - Installation
The damper the ground, the more suited it is to GSHP, due to the high water content. Dry, sandy ground doesn’t generate as much heat. While dry ground can generate around 20-25 Watts / metre, wet ground can generate up to 40 Watts / metre.
The area of land required to install a Ground Source Heat Pump varies depending on the type of installation required (Horizontal Array or Borehole) and the Brand / Model of heat pump being installed. In each case, Enerfina endeavours to find the optimal solution based on our customer’s requirements from our list of experienced suppliers, and tailored to fit his specific plans and circumstances.
Horizontal Array Heat Pumps will require more ground than Borehole Heat Pumps, as the coil is laid out horizontally across the ground. While an area of land of around 2-3 times the area of the house is ideal, there are a number of heat pump solutions available for which an area of land of around 1.5 times the total Square Metre area of the house is sufficient. For a Horizontal Array Heat Pump system, the pipes are typically installed around 1.5 metres below the surface of the ground, so it’s important to know what lies beneath the ground i.e. whether there is rock close to the surface, which would impede the digging of trenches. As an example, a 170 M˛ house would require approximately 6-8 horizontal trenches, each around 50 metres long.
Borehole Heat Pumps require much less space than Horizontal Array systems, as the main installation requirement is for two boreholes of suitable depth to provide the heat source for your home or property. As an example, a 170 M˛ house would require 2 boreholes of around 15-20 cm in diameter and 80-100 metres in depth. If you strike a water source on the way down, this will augment the level of heat energy generated from the borehole.
Borehole Heat Pumps require a certain amount of preparation / homework (reviewing of Ordnance Survey maps etc.) to ensure that the ground is suitable. They can also be slightly more costly than Horizontal Array systems, due to the drilling involved. However, they are a popular choice where customers wish to have the benefits of a Ground Source Heat Pump system, and space constraints prevent them from installing a Horizontal Array system.
Questions you should ask yourself include the following:
- How many Square Meters of ground do you have available to install a Heat Pump system?
- Is there rock just below the surface or can you easily dig to a depth of 1.5 metres across the area of ground?
- Is it an open area of ground or are there trees and roads running across the location?
Grants of up to €3,500 available
In Ireland, the SEI is promoting the use of Heat Pumps in the domestic residential market, via a range of initiatives including grants available as part of the Greener Homes Scheme. This has contributed to an increase in demand for Heat Pumps since early 2006, and it is expected that this trend will continue over the coming years.
Air Source Heat Pumps - General
As the term suggests, Air Source Heat Pumps (ASHPs) use the natural air to generate heat for heating space and water at a fraction of the cost of other sources such as oil or electricity. Air Source Heat Pumps are designed to suit the specification of your home or business premises and provide space heating via radiators or underfloor heating, as well as catering for your hot water needs. They also lead to a significant reduction in your energy bills.
Air Source Heat Pumps are an ideal solution for an urban / suburban setting, where space constraints rule out the installation of other renewable energy systems such as Ground Source Heat Pumps and Wood Pellet Boilers.
Air Source Heat Pumps – Installation
Air Source Heat Pumps benefit from a relatively straightforward installation (no excavation is required). It can also be integrated easily into existing properties (retrofit / renovation properties). Typically, the ASHP comes equipped with two separate units, one external and the other internal. The external unit (fan) is situated in a suitable outdoor location, either in the garden or on a terrace or balcony. The internal unit is connected to the external unit and the heat pump is controlled via the internal unit, which is turn is connected to the hot water cylinder and space heating system (radiators or underfloor heating).
The performance of Air Source Heat Pumps has been improving significantly in recent years. Some of models available through Enerfina (e.g. Daikin Altherma) have a COP (Co-efficient of Performance) of 4.2, which is one of the highest (if not the highest) available on the market.
To get better understanding of the Air Source Heat Pumps supplied by Enerfina, simply go to the “Want a quick quotation?” section on this page, enter your estimated House Size, select “Air Source” and click on “Show Products”.
Water Source Heat Pumps - General
Water Source Heat Pumps (WSHPs) operate based on the same principle as GSHPs except that a water source such as a well, stream or river is used as the heat energy source, as opposed to the soil. Many homes will have a water course passing nearby, perhaps right underneath your back garden, and this can be tapped into to provide the water source needed to heat your home.
Water Source Heat Pumps - Installation
Water Source Heat Pumps can be extremely efficient; certain models can reach an efficiency level of up to 6 -> 1. This means that up to 6 kilowatts of heat energy are generated for every kilowatt that is used to power the Heat Pump.
As previously mentioned, in order to be able to install a Water Source Heat Pump, you first need to identify a suitable water source such as a well, stream, river or reservoir nearby, or alternatively, you can simply ask a water diviner to confirm whether or not a water course runs close to your home. Once this is located, the next step is to drill two separate holes for your Heat Pump (one inbound and one outbound) at a suitable depth, and complete the installation.
If your Water Source Heat Pump is connected to a stream or a river, it is possible that the water levels will fall slightly during the summer months and this may influence the efficiency of the Heat Pump during this period. However, this can easily be offset by the use of a complimentary technology such as Solar Panels.
In practice, Water Source Heat Pumps typically work in one of 2 ways:
- The loop is inserted directly into the water source, or
- Water is cycled through the heat pump using filters
