Got a story? Ring us on 01732 748041 or e-mail email@example.com TRAINING/TECHNICAL Getting the best out of a heat pump The Renewable Heat Incentive has the potential to rejuvenate interest in sustainable heating and hot water technologies and to give the heat pump market a much needed boost. Martyn Bridges, of Worcester, Bosch Group, examines key considerations that need to be made prior to fitting a heat pump... As with the installation of any new heating and hot water appliance, each installation should be considered on its own merits as there is no such thing as a ‘one size’ fits all’ approach. Therefore, you need to consider each property on its own merits and challenges. When it comes to heat pumps in particular, the structure of the property is particularly critical to the ongoing efficiency of the system - not least because of the manner in which heat losses need to be accounted for, and minimised where possible. It goes without saying that with a number of technologies available on the heat pumps market, selecting the right type of heat pump is key to ensuring the end user can benefit from the best possible return on investment. TYPE OF HEAT PUMP To heat a radiator or underfloor heating system from a heat pump leaves the customer with effectively two choices of heat pump, either air to water or ground to water. The most common heat pump installation involves an air to water type. Essentially, an outside unit is used to collect a constant volume of air via a suction fan and apply the temperature (energy) in the air to a refrigerant circuit that is then compressed to a high temperature. This heat is then transferred into the primary water circuit of the heating system. Therefore, the external unit is generally sited fairly closely to the property and the major consideration would be the inevitable noise from the fan and as to whether this is suitable for the property in question. Ground source heat pumps (GSHPs) are designed to collect natural energy stored in the ground and convert it into a usable, sustainable source of heating and hot water for the home, usually without the need for an additional boiler. It is often argued that for 12 months of the year a GSHP is likely to be more efficient than an air source heat pump, simply because the temperature in the ground is more consistent than the temperature in the air. A heat pump is a perfect solution for many properties all year round, providing they are well insulated and the heat emitters are appropriately sized for the reduced flow temperature at which a heat pump operates. In properties where the insulation levels are not as strong, a boiler and heat pump hybrid combination should be considered. The ideal situation for maximum return from WWW.HPMMAG.COM An air to air heat pump, such as Worcester’s Greensource, is one of the two choices available when heating a radiator or underfloor heating system from a heat pump a heat pump is a new building (or newly renovated building that is up to current Building Regulations). It is still possible and practical to install a heat pump into an older property but it is imperative that the insulation is upgraded throughout the entire property, to maximise efficiency. The installer should check the property is as air-tight as possible and make suggestions on how to improve the insulation if it falls short of the latest Building Regulations. With sufficient insulation in place, it is important to evaluate the existing heating system, in particular the size of the radiators. A thorough heat loss calculation on the house, with the new insulation, would be recommended, to see whether the existing Getting Microgeneration Certification Scheme ready 34 FEBRUARY 2014 HEATING & PLUMBING MONTHLY radiators can provide the room temperatures required, but at the lower flow temperatures that the heat pump will generate, which is typically around 50°C. In the event that the radiators are not large enough, to maintain a comfortable temperature at these lower level temperatures, it is advisable to increase the physical size of the radiators, for example changing single panel radiators for double panel equivalents. This will also reduce the likelihood that any extra pipework will be required. Being mindful of each of these considerations will ensure the customer has a detailed understanding of how a heat pump can enhance the way they heat their home. enquiry number 123 With the possibility that an increasing number of homeowners will express an interest in heat pumps once funding is launched under the Renewable Heat Incentive (RHI), it is important for installers to get themselves up to speed with the latest product developments and legislation in order to maximise the benefits of this sector. Worcester will soon be offering recognised Qualifications and Credit Framework (QCF) affiliated training and assessment around renewables. QCF training is a more flexible way for installers to learn and one that is recognised by the Microgeneration Certification Scheme (MCS) - a must for those looking to take advantage of the business opportunities presented by the Feed in Tariff, the RHI and the Green Deal. Heat pumps in particular require a great deal of technical knowledge around best practice specification to ensure that not only is the most appropriate technology specified, but also that it is suitably sized to maximise efficiency gains. The QCF training programme on heat pumps has been written to cover each of these areas in depth, which can prove a more time effective way to comply with MCS requirements than by submitting a portfolio of work to show With MCS accreditation requiring heating engineers to prove specification, installation, and maintenance competence, as well as recognised industry qualifications, QCF training represents an attractive option for those wishing to enter the renewables market.
HPM February 2014
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