HEATING & HOT WATER T
In the design phases of a new non- domestic building, heat pumps are the leading alternative, but the roadmap to decarbonised heating across all building types is not at all clear, with many policy level decisions yet to be made. So, what will the plant room of the future look like asks Chris Caton, product director (commercial), Hamworthy Heating
Plant room of the future
here are key dates that will impact the future course of heating in the UK; the first major date being 2026. Here, the government is
set to make a final decision on the use of hydrogen for heating in buildings. This date will have a major impact on the future of heating in the UK which of course impacts the commercial plant room. However, I think the plant room in 2026 will look pretty much identical to the plant room of 2023. If that is the case, then when can we expect to see genuine changes in commercial plant rooms? There is one constant in all of this uncertainty, which is 2035. This date is significant, as an interim Net Zero target has been established for 2035 to reduce emissions in the UK by 78% compared to 1990 levels. It’s also the date set for all new heating systems to be Net Zero compatible. However, the recent Standards and Efficiency Consultation puts a question mark over this. Section one of the consultation surprisingly addresses improving natural gas fired boiler efficiency from the typical 5:1, to 10:1. This consolidation is for all boiler types up to 45kW and proposes these changes apply up to 70kW. To achieve this a significant jump in modulation is necessary that would require a big R&D investment from boiler manufacturers, which was entirely unexpected in light of the 2035 announcement. It is just a consultation, but it adds uncertainty to one aspect we thought was certain.
Having set 2035 as the date we
are focussing on, one little caveat in the form of the ‘MISSION ZERO Independent Review of Net Zero’ report produced by Chris Skidmore MP. This review recommends bringing the date forward to 2033.
The 2035 plant room
When it comes to new buildings, I think the 2035 plant room is relatively straightforward to predict as it must comply with Building Regulations or, as it will be post 2025, Future Buildings Standard. This means a thermally efficient
building with a low carbon-based heating system, maybe with additional renewables such as solar panels contributing to the running of the heat pump.
The heat pump itself will probably look very similar to current ones, but I would expect latest models to be delivering higher temperatures than are currently achievable where domestic hot water is needed. One of the main changes I foresee is the choice of refrigerants, with a move away from those that are harmful to the environment to those that have a lower Global Warming Potential (GWP). Ultimately, that means natural refrigerants such as propane with a GWP of four, or carbon dioxide which has a GWP of just one.
Whilst the 2035 heat pump will
probably visually look very similar to those we have today, the heating system fed by the heat pump should look a little different. That’s because accurate system sizing is very important to get the most energy efficiency from the heat pump. The Approved Document L uplift requires all new and replacement heating systems to be designed with a maximum flow temperature requirement of 55°C. This means bigger radiators are required to get that energy into the room, operating on that temperature. When we move away from new build to look at a refurbished commercial plant room, the picture is a little different. As we know, the majority of older properties have comparably poor thermal efficiency and to improve the thermal properties involves a whole host of expensive, disruptive work to the building. But without that work, relying solely on a heat pump which has a maximum flow temperature of 55°C is unlikely to provide the level of comfort required.
8 BUILDING SERVICES & ENVIRONMENTAL ENGINEER JULY 2023
Furthermore, the cost to run a heat pump in this way would also be very high. Here, expect to see hybrid systems which do indeed include a heat pump as the main heating source, but with the existing gas boilers retained (or maybe new hydrogen boilers!) to provide supplementary heat when required.
Looking further ahead: hydrogen
Taking into account a typical commercial boiler lifespan, by 2035 any current gas boilers in place are likely to need replacing and their replacements must be Net Zero compatible. So that means no new natural gas boilers. By 2050, will the hydrogen powered boiler be a staple of plant rooms? Clearly that depends on the government’s decision in 2026. If the decision is made against hydrogen, then it’s heat pumps all the way along with, maybe, electric heating. If the decision goes the other way, and hydrogen is going to play a part in heating in the future, then we have a quite different scenario, where gas boilers are more than likely to continue to form part of the heating mix as 100% hydrogen fuelled boilers simply don’t exist; no manufacturer has gone beyond
a prototype and those are for domestic boilers only. The amount of innovation and R&D involved in producing a boiler that can operate on natural gas like today, but then can be converted at some point to 100% hydrogen, is enormous and, ultimately, years away.
Diversification
There’s only one thing we can be certain of in this uncertain decarbonised heating future, and that’s diversification. The commercial plant room of the future will feature a mix of technologies to satisfy the heating requirements of different building types, old and new, and to make best use of energy prices. I’m going to stick my head out and say that hydrogen will form part of that mix and will replace natural gas along with the other key heating technology which will undoubtedly be heat pumps. But there may well also be direct electric heating in the mix, and that could be through immersion heaters, or it could be electric boilers, or it could be panel heaters. The plant room of the future is unlikely to rely on a single heating method but will feature a combination of these to deliver energy efficient, decarbonised heating in an intelligent way to minimise operating costs.
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