HEAT PUMP GUIDE From the editor T major role in this.


This means that heat pumps have never been more important in how we will heat our homes and businesses in the future. This message is reinforced by The Committee on Climate Change which has


Heat pumps grow in importance


he government is committed to achieving its net zero target by 2050 and phasing out fossil fuels will play a


highlighted the importance of heat pump installations in carbon reduction initiatives. In addition to their eco-friendly credentials, heat pumps are also often described as a cost-effective alternative to competitive heating solutions. However, it is crucial that they are correctly


installed and The Heat Pump Association (HPA) has long been pushing for a nation-wide


training programme to develop the standard of skills required. The intention of this supplement


is to provide a detailed technical guidance to contractors about of the heat pump ranges that are available within the local market as they grow in significance for the UK. Turn to page 32.


Heathe Ramsden, Edito Groundwork partners


Steve Richmond, head of marketing and technical at REHAU Building Solutions Division, explores the latest innovations in heat pump and district heating technology with a focus on fourth-generation solutions


I


n February 2019, the Committee for Climate Change (CCC) published a report outlining suggestions for reducing emissions worldwide. As a result, the


Government pledged to achieve ‘net zero’ carbon emissions by 2050, and also implemented the Future Homes Standard 2025, which banned the installation of fossil fuel boilers in new build homes. Heat pumps, particularly large-scale units for district heating networks, are increasingly under consideration from developers and contractors. Indeed, the tenth version of the Standard Assessment Procedure for building regulations (SAP 10) consultation states that an emissions factor for electricity value of 0.233 kg CO2/kWH should be used to as opposed to the current SAP 2012 value of 0.519. Since this initial step, the Draft SAP 10.1 consultation, published in October 2019, has proposed an even lower value of 0.136, a 75% improvement from the SAP 2012 figures for electricity-derived carbon savings from heat pump usage. This was published alongside new Part L and F Building Regulations which are due to come into force in 2020 and define minimum carbon reductions. This level of efficiency can be achieved with


centralised commercial-scale heat pumps at low or ambient temperature. In addition, the Heat Networks Investment Project (HNIP) favours developments with these systems when awarding their grants.


The next generation


District heating networks use a central heat source to supply multiple buildings via a network of underground pre-insulated pipes. By efficiently providing heat to multiple buildings from one source, this technology reduces carbon emissions while eliminating the need for individual boiler


30 April 2020 Finding suitable pipework


maintenance and its ensuing costs. The networks currently in operation are mostly third-generation, typically using gas CHP to circulate water at 70- 95ºC. To achieve net zero emissions with district heating systems, centralised heat pumps or waste heat sources are suitable. In addition, according to CIBSE/ADE CP1 – the code of practice setting out minimum requirements for heat networks – developers must not have a flow temperature exceeding 70ºC for new projects. With lower flow temperatures of 40-60ºC, the


latest fourth-generation district heating networks often use centralised air, water or ground source heat pumps, or waste heat, meaning carbon emissions are significantly reduced compared to fossil fuel networks. These more energy-efficient networks benefit from lower heat losses and can satisfy consumer demand in both an environmentally friendly and energy-efficient way. Reductions in heat losses from lower flow


temperatures, smaller pipe sizes, and the resulting reduced capital and operational costs have made fourth- generation technology a more attractive option for developers. Furthermore, improved energy efficiency and emissions rates, along with lower installation and maintenance costs, also mean district heating systems deliver on the Government’s demands for net zero emissions alongside lower energy bills.


A growing preference for cost-effective and energy- efficient heat pumps within district heating solutions has resulted in more specifiers and contractors considering polymer pipework due to the lower temperatures. To meet this consumer, government and developer demand, companies such as REHAU are developing district heating solutions that help lower emissions and capital costs. Pre-insulated pipework solutions, such as Rauvitherm and Rauthermex, are polymer options for district heating networks. Combining flexibility and low heat losses, Rauvitherm suits small-medium size heat networks or house connections from a main spine of the network. For larger networks, the insulation afforded by the high-performance polyurethane rigid (PUR) foam used in Rauthermex ensures minimal heat losses and enhances system efficiency across the network. Both options can be quickly and easily installed, affording developers and contractors flexibility and adaptability throughout design and onsite construction processes. Additionally, polymer pipework avoids costly


system failure and repair work due to corrosion, which its traditional steel counterpart can often experience. The lower flow temperature of a fourth- generation network also allows for a lifespan well in excess of 50 years for polymer pipes. Using polymer solutions, achieving net zero


targets in the rapidly changing low-carbon heat market is more attainable as a long-term solution for developers, contractors and other stakeholders. With low-carbon heat constantly at the top of the


agenda, heating our building stock with efficient district heating networks has become an even more viable option.


www.heatingandventilating.net


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