BOILERS, PUMPS & VALVES
PLANNING A MULTI-TECHNOLO With a 2050 Net Zero target enshrined in law, the direction
of travel to low carbon heat is clear. But with no silver bullet for decarbonising existing commercial buildings, a mix of technologies will be required to set them on a Net Zero pathway, says Baxi’s head of technical solutions Andy Green
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on-domestic building stock represents 23% of built environment emissions with 66% of
commercial building emissions currently attributed to heating. This means action by owners and managers of non-domestic buildings is urgently needed to accelerate energy efficiency measures and keep on track for 2050 net zero. For new commercial buildings, more rigid efficiency requirements from the 2025 Future Buildings Standard will look to enforce low carbon heat, phasing out fossil fuel boilers in these properties. New buildings will be designed from the outset for Net Zero, with heat pumps a favoured technology to meet the tighter emissions standards. This effectively rules out natural gas boilers in new builds. But the pressing challenge, as we all know, is tackling heat decarbonisation in our existing building stock. And here condensing boilers arguably still have a role to play, whether that’s improving energy efficiency at an early stage of the decarbonisation journey or meeting peak demand in a hybrid heat pump system.
DECARBONISING HARDER-TO-HEAT BUILDINGS Traditionally, older commercial buildings have relied heavily on gas boilers and water heaters to provide a readily available energy source for heating and hot water. Moving these buildings towards
lower carbon heat can seem a daunting process – and certainly it’s one that should not be trivialised. Given the huge diversity of building types, each with their own individual requirements and limitations, including available budget, space and electrical supply, there is no silver bullet. Rather, it’s likely that a phased, multi-technology approach will be required. Where to begin? Defining the immediate,
medium and long-term goals is a good starting place as is early engagement with experienced heating solutions providers. Understanding the available time to complete the work, the budget and any funding opportunities will make it possible to define, plan and design the various stages of the pathway. With this in mind, let’s consider some of the options, technologies and approaches.
REDUCE ENERGY DEMAND AND HEAT LOSSES The first step, irrespective of the heating technology that may eventually be used, is to identify ways to reduce energy demand. Energy efficiency is crucial to cut carbon emissions and operating costs and should always be a priority in existing buildings. Taking time at the outset to gather real,
measured data on the existing building and heating system is key to developing a full understanding of the thermal performance of a building. Only when we know how and where energy is used can we develop solutions to reduce demand and improve the building’s operational efficiency. As part of the investigative process,
look to identify any feasible opportunities for fabric upgrades to reduce heat losses. The benefit of reducing heat loss is that it can significantly reduce the size or capacity of plant required – which in turn reduces capital expenditure – while improving running costs by limiting heat loss to the environment. Measures might include roof and wall insulation, draught proofing and improving the thermal performance of windows and doors.
A packaged plant room including condensing boilers enabled one NHS Trust to meet the requirements for more energy-efficient heating, minimal disruption and future flexibility
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OPTIONEERING With real measured data, solutions providers like Baxi can then engineer different design options, backed with predicted energy and carbon savings and capital expenditure modelling. Pre- sales optioneering is a valuable stage that allows building managers and
ENERGY & SUSTAINABILITY SOLUTIONS - Autumn 2024
The Remeha Commercial HVAC Manager provides the option to cascade up to eight heat generators, either heat pumps or a combination of heat pumps and commercial condensing boilers in a hybrid installation
designers to make the best choice for the building within the project parameters.
ALL-ELECTRIC APPROACH Ultimately the goal is to move towards low carbon heating technologies. And with the arrival of high temperature heat pumps, moving directly to an all-electric solution might be a possibility in some buildings. The ability of high temperature air source heat pumps to work at higher temperatures – up to 80°C flow temperature in the case of Baxi’s Auriga HP+ air source heat pump – provides more options for buildings like hospitals, hotels and leisure centres where there is a high demand for hot water at peak times. Ask your chosen solutions provider for advice on the various factors – such as location, budget, electrical supply, size of cylinders etc. – that should all be considered at the outset.
PHASED APPROACH Realistically, however, the ability to retrofit a high temperature heat pump and ensure optimal heat pump performance and value will depend on where the building is on its decarbonisation roadmap. For some buildings, the immediate, achievable option might be to replace inefficient existing boilers with modern condensing models. As the latest models of condensing boilers are up to 20% more efficient than standard boilers, this early energy efficiency measure can drive down energy consumption and emissions considerably as well as improving comfort levels. However, while boiler replacement has a place, it’s still important to plan ahead, using the installation to make the heating system more efficient and ready for future project phases. Taking the opportunity to address the system’s
distribution pipework and heat emitters, for example, will allow the system to operate at more efficiently at a maximum flow temperature of 55°C (or lower), in line with Building Regulations. This allows the condensing boilers to operate in condensing mode, where they achieve their maximum efficiencies. It will also prepare the heating system for the integration of low temperature
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