Heat flows naturally from a higher to a lower temperature. Heat pumps, however, are able to force the heat flow in the other direction, using a relatively small amount of high quality drive energy.
Thus heat pumps can transfer heat from natural heat sources in the surroundings, such as the air, ground or water, or from man-made heat sources such as industrial or domestic waste, to a building or an industrial application.
Because heat pumps consume less primary energy than conventional heating systems, they are an important technology for reducing gas emissions that harm the environment, such as carbon dioxide (CO2), sulphur dioxide (SO2) and nitrogen oxides (NOx).
Types of Heat pumps
Air-source heat pump
Heat your building with energy absorbed from the air around you
Air source heat pumps absorb heat from the outside air. This heat can then be used to heat radiators, underfloor heating systems, or warm air convectors and hot water.
An air source heat pump extracts heat from the outside air in the same way that a fridge extracts heat from its inside. It can get heat from the air even when the temperature is as low as -15° C. Heat pumps have some impact on the environment as they need electricity to run, but the heat they extract from the ground, air, or water is constantly being renewed naturally.
How does the air source heat pump work?
Heat from the air is absorbed at low temperature into a fluid. This fluid then passes through a compressor where its temperature is increased, and transfers its higher temperature heat to the heating and hot water circuits of the house. There are two main types of air source heat pump system:
- An air-to-water system distributes heat via your wet central heating system. Heat pumps work much more efficiently at a lower temperature than a standard boiler system would. So they are more suitable for underfloor heating systems or larger radiators, which give out heat at lower temperatures over longer periods of time.
- An air-to-air system produces warm air which is circulated by fans to heat your home. They are unlikely to provide you with hot water as well.
Ground source heat pumps
Heat your building with energy from the ground
Ground source heat pumps use pipes which are buried in the garden to extract heat from the ground. This heat can then be used to heat radiators, underfloor or warm air heating systems and hot water in your home.
A ground source heat pump circulates a mixture of water and antifreeze around a loop of pipe – called a ground loop – which is buried in your garden. Heat from the ground is absorbed into the fluid and then passes through a heat exchanger into the heat pump. The ground stays at a fairly constant temperature under the surface, so the heat pump can be used throughout the year – even in the middle of winter.
The length of the ground loop depends on the size of your home and the amount of heat you need. Longer loops can draw more heat from the ground, but need more space to be buried in. If space is limited, a vertical borehole can be drilled instead.
How does the air source heat pump work?
Heat from the ground is absorbed at low temperatures into a fluid inside a loop of pipe (a ground loop) buried underground. The fluid then passes through a compressor that raises it to a higher temperature, which can then heat water for the heating and hot water circuits of the house. The cooled ground-loop fluid passes back into the ground where it absorbs further energy from the ground in a continuous process as long as heating is required.
Normally the loop is laid flat or coiled in trenches about two metres deep, but if there is not enough space in your garden you can install a vertical loop down into the ground to a depth of up to 100 metres for a typical domestic home.
Heat pumps have some impact on the environment as they need electricity to run, but the heat they extract from the ground, the air, or water is constantly being renewed naturally.
Why should I install a heat pump?
- Lower energy bills. One unit of electricity can generate in excess of four units of heat depending on energy source.
- Tax free income*. The Renewable Heat Incentive, due for launch in April 2011 will provide long term income based on the amount of energy your heat pump produces. *Pre Budget Report Jan 2010.
- True “green marketing” edge. Positive image for promotion of your building and services.
- Helps meet new low energy legislation. Ensures your building meets Code for Sustainable Homes and Part L Building Regulations.
- Safe – They do not burn fossil fuel so have no risk of carbon mono-oxide poisoning.
- Simple to operate – The system automatically adjusts to weather temperature and heating demand to provide heating and hot water when you want it. Doesn’t need fuel deliveries
- Flexible – Space heating can be delivered through any mixture of underfloor heating, Thermaskirt and low temperature radiators.
- Longevity – Typical heat pump lifespan is twice that of a traditional boiler
- Needs little maintenance – they’re called ‘fit and forget’ technology.
- Reliable - Constant supply of energy as the system does not depend on variable levels of sunlight or wind
- A low carbon heating solution. Reduces CO2 emissions by delivering more equivalent units of heat than it consumes in electricity, UK fossil fuel consumption and CO2 emissions are reduced, minimising you carbon footprint
- The highest heating efficiency for every 1kWh of electricity used to run the heat pump, up to 4kW of useful heat is provided, giving the heat pump an efficiency of up to 400%.
Underfloor heating is far from a new concept, it was first used by the Romans whose dwellings were constructed with voids through which air, warmed by an open fire, would pass, thus heating the structure.
Underfloor heating is not a new concept in this country either. In the past electric heating elements were buried within floor screeds. These were heated overnight using “cheap rate” electricity. However, this method was expensive to run and uncontrollable and the building would over heat during the day but in the evening, when heat is generally required, no further heat was available.
Utilising today’s modern multilayer pipes, control systems and high efficiency boilers, the underfloor heating systems of today are extremely comfortable and controllable. Radiators are no longer needed so giving more room space. The heat is more evenly distributed and dust is not circulated.
Underfloor heating from the whole floor area of the house gently warms the air above, eliminating cold spots. The warm air convects from the floor surface losing approximately 2 degrees centigrade at 2.0 meters above the floor, which makes the system ideal for all ceiling heights.
Independent tests reveal that the most acceptable indoor climate is one in which the floor temperature ranges between 19-29°C and the air temperature at head level ranges between 20 and 24°C. With radiator or convector heating systems a vertical temperature gradient is produced; colder at foot level than at the head.
Underfloor heating has made it possible to reduce energy consumption by using low water temperatures. These systems, based on the development of complex and very high quality plastic pipe, such as the multilayer pipe, now account for over 60% of some European heating markets.
Features and benefits of the underfloor heating
- Space & Economics – Every square metre of your home can be fully utilised and the cost for our system is very similar to a radiator system.
- Hygiene – No dust and the underfloor heating will help to reduce house dust mites which is a benefit to asthma sufferers. Moisture content is too low, to support dust mites.
- Aesthetics & Labor Saving – You can design your home to suit your needs rather than that of your heating engineer. Cleaning of the floors is easier and wet floors dry very quickly. Prevents discoloration of paintwork, peeling of paper etc.
- Silence & Comfort – Radiant heat will provide the highest comfort levels at an even temperature throughout. Compared to radiator systems, there is no noise. No annoying ticking as pipes expand in floor voids.
- Cost effective – It has been proven that energy saving from 15-40% can be achieved with underfloor heating.
- Ease of control – Small temperature between the floor surface and the air above means the system is practically self-regulating.
See the difference between a conventional radiator heating and the underfloor heating technology