SPONSORED ROUNDTABLE | HEATING When I suggest things such as getting rid of boilers and installing PVs, not only are costs increasing, but embodied carbon is going up too, which really concerns me Louis Kimber Noise and vibration produced by ASHPs is an issue that some manufacturers and noise specialists have said is often overlooked. Hoare Lea has an acoustics team that assesses the operation of the ASHP, and it advises architects on the type of materials and vibration mounts that should be used. A lot of the kit were using with ASHPs is a set size, but massive generation packages are needed on site, so there are space constraints, said Stark. The acoustics are achievable, but the space needed is challenging. So, before we even involve an acoustics specialist, we allow enough space for these packages for all residential projects, because we know we will need it. Owens other main complaint relates to the Building Regulations. If we want to decarbonise, the regulations need to be amended to make it work and enable the best technologies to be put forward, he said, citing a frustrating experience he had with a residential new build. To achieve the SAP calculation, he had to install gas combination boilers with photovoltaics instead of heat pumps. This is not right, because the SAP calculation looks at affordability, said Owen. An ASHP is given a C rating because its less affordable, while a gas combi boiler with PVs gets an A rating; its ludicrous. Louis Kimber, mechanical engineering technician at AtkinsRalis, said embodied carbon is a growing issue. He has been working with the Government Property Agencys (GPAs) UK sites and exploring what can be done to decarbonise. Embodied carbon is not a criterion required by the GPA, said Kimber. But when Im writing the reports and suggesting things such as getting rid of boilers and installing PVs on the roof, not only are the costs increasing, but the embodied carbon is going up too, which really concerns me. Kirkwood said it was refreshing to hear his own concerns echoed. We find there is a great deal of confusion and people are often looking for a quick fix, he added. Engineers need time to engineer, to survey and to monitor. As an industry weve almost engineered that out and we need to engineer it back in. To optimise heating systems, Skidmore recommended metering be installed in existing buildings, to help understand heating use. An existing system with lower temperatures should be run to see how it behaves. Suggested improvements, he Engineers need time to engineer, to survey and to monitor. As an industry, weve almost engineered that out Ryan Kirkwood added, have included upgrades to building fabric, the introduction of ventilation, using domestic hot water with AHUs, and providing enough space for airflow in heat pumps, as correcting flows can be a problem. Skidmore also recommended using high-efficiency chillers to take the rest of the cooling, instead of implementing a blanket approach. In buildings that have a 24/7 operation where there is a constant cooling demand, he has taken advantage of the waste heat element of ASHPs. However, he argued that ASHPs are the biggest offenders in terms of energy consumption, because they are not being controlled properly. We often find that buildings arent running as smoothly as they should. They are sometimes running at night when they shouldnt and not ramping down enough when they should, said Skidmore. The controls element has been as much a culprit as the plant. We often find that there has been a lack of engagement with the facilities management [FM] team regarding the controls. There have also been If we want to decarbonise, the regulations need to be amended to make it work and enable the best technologies to be put forward Jeremy Owen 26 December 2023 www.cibsejournal.com CIBSE Dec 23 pp24-27 BAXI Roundtable 2.indd 26 24/11/2023 17:49