HVAC for schools


An education in heat decarbonisation


The year 2050 may seem a way off, but schools should start planning for the energy transition now, says Anne Wraith, Baxi’s head of building services. And when it comes to refurbishing the heating system, manufacturers are at hand to offer specialist support


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t is well established that decarbonising heat in buildings is critical if the UK is to achieve its net-zero ambition. But this is a huge challenge and one that is especially complex for schools due to the variety of building types across the estate. Funding and time constraints are further typical barriers to delivering retrofit, influencing how quickly and easily it can be achieved. On the upside, there are achievable opportunities to tackle and overcome the challenges ahead. But given that, realistically, decarbonisation will not be achievable overnight in many harder-to-tackle buildings, it is critical that these schools start planning their route to net zero sooner rather than later – and that the heating industry works together to provide the necessary guidance and support.


Energy efficiency


Where, then, to begin? The first step should always be to identify ways of reducing energy demand in the building. Irrespective of the low-to-zero technology that may eventually be used, energy efficiency is crucial. Understanding where and how energy is being used will help determine any opportunities for improvement. If funding is tight and the building is relying on


old, inefficient boilers, for example, replacing them with modern condensing boilers that are up to 20% more efficient is a practical early step towards the school’s long-term goals. On most projects it should be possible to


address the system’s distribution pipework and heat emitters to operate at lower temperatures than the traditional 82°C/71°C or 80°C/60°C flow and return system designs. This will allow the condensing boilers to operate in condensing mode, where they achieve their maximum efficiencies. It will also future proof the building and prepare the heating system for the integration of low carbon technologies at a later stage.


Heat pumps


Heat pumps have a major role to play in the transition to low carbon heating. We see air source heat pumps (ASHP) as the most popular and cost- effective choice of heat pump and are pleased to be adding new high temperature and low temperature ASHPs to our existing Remeha range this year. Typically, when considering installing heat pumps


16 April 2023


www.heatingandventilating.net


Anne Wraith, head of building services, Baxi


into older buildings, the fabric of the building, the compatibility of the existing heating system, heat loss calculations, the available electricity supply and any other necessary updates will all need to be considered at the outset. Where an all- electric approach is not a feasible option initially, a multivalent approach should not be overlooked.


Up to 70% savings from bivalent systems


Bivalent systems that combine heat pumps and highly efficient condensing boilers provide a practical solution to improving heating performance in hard-to-decarbonise schools. In our free guide Schools and the heat decarbonisation challenge, we describe the steps involved in a phased approach to decarbonising heat, progressing from old non-condensing boilers to a bivalent heat pump and boiler system. Using simulation software, we show how in a typical primary school, the reduction in total energy consumption (gas and electricity) from the refurbishment can be as much as 70% with an associated drop in emissions. This approach will help schools make dramatic leaps towards their sustainability goals. The remaining natural gas use can eventually


be cut by using renewable gases, such as green hydrogen. Replacing natural gas with 100% hydrogen might currently be at the discussion stage, but it is worth noting that all five of Britain’s gas grid companies are ready to deliver a 20% blend of hydrogen from this year. Why is this important? Because blending just 20% of hydrogen into the gas grid will reduce carbon emissions by the equivalent of 2.5 million cars a year, according to the ENA.


Choosing boilers like the top-of-the-range Remeha


range that are not only highly efficient but certified to operate on a 20% hydrogen blend, will mean no need for changes to the boilers or heating system.


Start planning now


Ultimately, the options today for schools will depend on where they are in their decarbonisation journey. Our specialist Building Services and Public Health teams are at hand to support contractors and consultants with free site surveys to help identify any issues and advise on the best approach on a project-by-project basis. By taking a holistic approach now, potential problems can be avoided in the months ahead. And by working together as an industry, we can urge schools to start planning proactively for a low carbon future.


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