Heat Pumps Today

CMYK / .ai CMYK / .ai CMYK / .ai www.acrjournal.uk/heat-pumps Pump up the volume The role of heat pumps in the struggle to reduce carbon emissions has been highlighted following the recent alarming report by the IPCC, which warns that climate change is already happening and is set to get considerably worse. Heat pumps oer a double whammy in terms of environmental benefit. First, they run on electricity and, if this is generated using renewable technologies such as wind turbines and solar panels, then they can be a carbon-neutral way to heat (and cool) buildings. Secondly, heat pumps are far more ecient than direct forms of heating and therefore use less energy in any case. www.klima-therm.co.uk H Y B R I D H E A T P U M P S Heat pumps are greener and cheaper to run than systems based on combustion such as boilers and they are safer and cleaner to operate. As a result of these benefits, heat pumps are gaining a significant foothold in the UK. Consulting firm Delta Energy & Environment, for example, estimates that current annual sales of heat pumps are just under 30,000, but that this will grow to more than 45,000 by 2025. It points out that the government’s announcement that fossil fuel heating could be banned in all new homes built after 2025 means there will be significant opportunity for low carbon heating, including heat pumps ( https://bit.ly/31DCOMe ). It says: “Despite the uncertainties surrounding future support for heat pumps after the Renewable Heat Incentive ends in 2021, and the potential negative impacts of Brexit on the heating market… our central forecast foresees the UK heat pump market doubling in size by 2025.” And it adds: “Increasing uptake in the new build market will be the main driver for this growth, supported by some large- scale shared ground loop projects and increased confidence in hybrid heat pumps. Though we believe growth could be more than twice as high to 2025 with the right policies and regulations – and if fossil fuel heating is then banned in new builds – we could see the market really take o from 2025 onwards.” But it is not only domestic and commercial heat pumps that are increasing in popularity. The benefits of ‘hybrid’ system incorporating heat pumps are also starting to be recognised. For example, the Rhoss EXP/HT is an all-electric low carbon system solution that ensures complete building cooling and heating all year round from a single system. It uses hybrid four-pipe air or water source heat pumps to produce simultaneous or independent cooling and heating (using heat recovery wherever possible for “free” heating or cooling), with typical chilled water temperatures of 6 or 7°C and hot water temperatures typically up to 50°C for space heating, which is then boosted up to as much as 78°C for domestic / sanitary / HWS demands. The ‘booster’ part of the system comprises a stand-alone high temperature water source heat pump to eciently boost medium grade heat to high grade heat. This arrangement generally results in higher plant utilisation, with heat recovered from the cooling cycle being used to help the high temperature heat pump deliver total energy eciency ratios (TER) of 7.0 to 8.0. Another example is the three-coil integral DX heat pump air handling unit – 3DxHP Series for ultra-low carbon defrost- free operation. The use of AHUs with integral refrigeration is a well-established but fast-growing sector of the air conditioning industry. The greening of the electricity grid is such that the electrification of heat is a firm part of our legislated lower carbon future. The use of heat pumps, rather than direct electrical heating, makes the best use of this cleaner electricity. Heat pump AHUs have typically always had an “Achilles Heel”: the threat of loss of performance during defrost cycles, just when you really need heat, is a major problem. This has traditionally been addressed using direct electric heating, but the innovative design of the 3DxHP Series product range uses the heat pump’s own energy to prevent any need for a defrost cycle at all. The system uses less energy than a traditional system and provides the guarantee of useful heat when it is needed most. Since space is always at a premium in building design and refurbishment, the fully packaged heat pump AHUs provide a compact and integrated design for the heating and cooling needs within our built environment, often without any need for further external heating or cooling sources. Installation costs can be significantly reduced as there is no external heating source (boilers or external heat pumps) or cooling source (chillers) that must connect to the AHU, because the refrigeration system is integral to it. The fact that the unit is factory assembled and tested ensures the quality is consistently high, unlike some site-based system assemblies. The built-in refrigeration system minimises the refrigerant content, eliminating pipe runs through the building and dramatically reducing the refrigerant content in comparison to VRF systems. 19