Heat Pumps Warm up Prospects for Installers

, 20.06.2011

Over recent months, the subject of renewable heating technologies and, particularly heat pumps, has certainly been playing on many contractors’ and installers’ minds.

Earlier this year, the Government announced its plans for the Renewable Heat Initiative (RHI) scheme, which will reward homeowners for using renewable products and systems to heat their homes, and to provide domestic hot water requirements. Over the forthcoming months and years, heat pump technology will therefore become a serious, mainstream sector of the multi-billion pound domestic heating industry, and installers will need to acquire greater, more detailed knowledge and training on renewable technologies, in order to benefit from the forecast surge in demand for heat pump installations.

 

As a mark of quality, and offering access to these homeowner incentives, installers holding MCS certification will, inevitably become the preferred choice for customers across the UK looking to have renewable heating technologies installed in their homes. In order to benefit from incentives such as RHI, both the product and the installer will need to be MCS accredited, so installers looking to grow their business using renewable technologies such as heat pumps should be acting now to attain accreditation.

Heat pumps have until recently tended to be for the dedicated heat pump installer. Increasingly however, as straightforward air to water monobloc heat pumps (which incorporate sealed refrigerant circuits and need no refrigerant handling qualifications),appear on the market, there is no doubt that they will become more significant to the wider market.

The two most common forms of heat pump: the Air Source Heat Pump (ASHP) and Ground Source Heat Pump (GSHP) can help reduce a dwelling’s carbon footprint, and significantly reduce homeowners’ fuel bills compared with traditional methods.

Although heat pumps are not zero carbon technologies as they require electricity to run, the heat they extract from the ground or air is constantly being renewed, naturally, so the impact on the environment is far less significant.

Heat pumps deliver heat at lower temperatures over much longer periods than traditional gas or oil boilers, so to get the most from them they should be left to operate 24/7, to heat efficiently. Due to the lower flow temperatures, radiators won’t be as hot to touch as when used with a traditional gas boiler.

An air source heat pump extracts heat from the outside air in the same way that a fridge extracts heat from its inside – basically it is a chillier, but in reverse. It can extract heat from the air even when the outside temperature is as low as minus 15°C.

An air to water heat pump system distributes heat via the wet central heating system and works much more efficiently at lower flow temperatures and higher ambient temperatures. They are, thus, most suitable for under floor heating systems or larger radiators (in a refurbishment situation radiators may have to be resized accordingly), which give out heat at lower temperatures over longer periods of time.

Often being small and compact, air source heat pump systems do offer a significant advantage over much larger ground source heat pumps where the necessary installation of ground loops can result in the need to dig up garden space to accommodate.

Taking energy from the stable heat source of the ground, installing a ground source heat pump does require a large upfront investment in a ground loop which can be installed either horizontally or vertically in outdoor space. Typically a ground loop will need to measure 3 x the m2 of the property.

A GSHP works in a similar fashion to the ASHP but circulates a mix of water and antifreeze around a ground loop buried in the garden. Heat from the ground is absorbed into this fluid, which is pumped through a heat exchanger in the heat pump. The ground heat (not particularly hot at this stage) is passed through the pump’s compressor to achieve a higher temperature capable of heating water for central heating and hot water needs. Ground loop fluid, which is now cooler, passes back into the ground where it absorbs further energy in a continuous process. When it is installed, like their source heat pump, it is virtually maintenance free.

The Energy Saving Trust recently published ‘Getting warmer: a field trial of heat pumps’ which came up with some interesting results. The study conducted over 83 sites found that “although every home is unique, it has been shown that a well-performing heat pump can produce a COP and system efficiency ratio of at least 3.0.” This means that for every kW of electricity used there is a useful output of three kW of heat. “These best-performing installations should give consumers confidence that heat pumps can provide good levels of central heating, lower carbon emissions, and reduce fuel bills when installed properly.” Approximately 13% of sites used in the trial, achieved system efficiencies greater than 3.0 however heat pumps are sensitive to design and commissioning, and efficiencies can vary accordingly.”

The report highlighted the need for heat pump installers to be well trained and familiar with the technology, however it also recommended simplicity in the design of systems; there were many configurations monitored in the field trial and “in most cases, the simplest designed systems performed with higher efficiencies”.

There is no doubt that heat pump technology is here to stay and will become a significant part of the domestic heating industry over the forthcoming months and years. In many cases heat pumps may well be fitted as well as a boiler to offer flexibility, perhaps as part of a hybrid system; manufacturers are continually working to develop new and innovative renewable domestic heating systems.

In light of the changing nature of the domestic heating industry, and the rapid growth in the heat pump market, it is important that installers looking to make renewable heating a key part of their business, continue to develop their understanding of renewable technologies including heat pump systems, and incorporate these technologies as part of their business offering.

* ‘Getting warmer: a field trial of heat pumps’, EST, September

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