HEAT NETWORKS | BRADFORD HEAT NETWORK HEAT NETWORK ZONING To support the development of heat network zones in England, the government introduced the Energy Act last October. The act provides powers for government to implement heat network zoning in England through regulations, which will include powers to designate city areas as heat network zones. Heat networks developed in these zones must be low carbon. Certain buildings and heat sources will then be required to connect to these heat networks within a specic timeframe. The government is currently working with 28 cities and towns to develop a methodology for identifying and designating heat network zones. The methodology will consider data such as location and building type, size and existing energy use, among other factors. network in line with what the buildings actually need, down to 65oC in summer, which means we are maximising heat pump efficiency throughout the year, explains Ridge. 1Energy did look at having a lower system temperature, but the cost to customers of upgrading their heating system and enhancing the fabric of their buildings would have been prohibitively expensive. We have had to drop a bit of system efficiency by raising the supply temperature, even with this weather-compensated approach, but it is far more beneficial to do this than to try to get customers to modify their systems, because the capital cost would have been too high to make it worth their while. Customers access the heat network through a plate heat exchanger, slotted into their existing plantroom as a replacement for gas boilers. Another major technical challenge is the need for the system to maintain a large temperature differential between system flow and return to further maximise heat pump operating efficiency. We have to design the system to provide the flow temperature needed to keep the buildings warm, but a lot of these buildings also have really poor temperature differential control. So while we might have a flow temperature of 80oC, it might only drop to 75oC on the return, when our system would prefer a much lower return temperature, explains Ridge. Rather than simply dictate the temperature differential that a customers system has to deliver, 1Energy is funding FairHeat to undertake surveys of potential customers buildings and heating systems. These help 1Energy, which will be operating the network, and its customers understand the interventions needed to increase the temperature differential, and the potential cost of these works. Armed with building-specific knowledge, 1Energy and FairHeat can support customers with their Public Sector Decarbonisation Scheme grant applications. Its been a significant investment in time, but we simply wouldnt have got to where we are in terms of helping building owners figure out the best way to decarbonise and connect to our network, says Ridge. For the BEN, the ASHPs will be installed in a purpose-built energy centre. The units will be split, with dry evaporators The proposed energy centre in Bradford 40 January 2024 www.cibsejournal.com CIBSE Jan 24 pp38-41 Bradford heat network.indd 40 21/12/2023 18:13