Heating for the Future

Buildings are the largest energy consuming sector in the world while in the UK, commercial buildings alone account for 18 per cent of our total carbon emissions. With heating one of the largest single end users of energy, James Porter looks at the importance of refurbishing our existing buildings and the energy saving opportunities

There’s not getting away from the fact that buildings are big users of energy. The more energy we generate within them, the more greenhouse gases we emit and the greater our energy bills. The introduction of tighter regulations has encouraged the design of more sustainable, energy-efficient buildings, but the city of the future will not be made up entirely of new buildings. Rather, our existing buildings are expected to form the majority of our building stock for many years to come, with research from the Carbon Trust estimating that 60 per cent of the buildings that will be standing in 2050 are already built. Given that we have a binding target under the Climate Act to reduce our GHG emissions by 80 per cent by 2050, addressing the energy efficiency of our notoriously inefficient existing building stock through refurbishment is crucial if we are to come anywhere near meeting our environmental commitments.

Raising thermal efficiencies

So, where to start? Heating and hot water generation is a large user of energy, accounting for over half the total energy use of a building and its associated emissions. With commercial boiler plant providing heating for a high proportion of non-domestic buildings, retrofit and refurbishment are the simplest, most affordable, and sometimes the only means of achieving significant energy and carbon savings. Replacing any inefficient or ageing boilers with modern, high-efficiency, fully-modulating condensing boilers will bring improved design flexibility, greater reliability and better control for immediate environmental benefits at a rapid return on investment.

A recent refurbishment project for the spinal injuries charity Aspire at its Leisure Centre in Stanmore, Middlesex, is a perfect example of the energy saving potential offered by condensing boilers. Remeha Quinta Pro condensing boilers in cascade operation were specified to provide hot water for showers, underfloor heating and to ensure reliable heating of the water in the swimming pool to a constant temperature of 31⁰C for the safety and benefit of its users. Not only have the new boilers achieved these key concerns, but they have delivered energy savings of £7,000 in just six months. Meanwhile, Remeha Gas 210 Eco Pro replacement boilers installed in the refurbished plant room at the historic Abbey Hotel in Bath, are anticipated to make realistic energy savings in the region of 40 per cent, a figure which equates to an annual saving of around £10,000.

Smart system design

The energy and carbon savings benefits of condensing boilers are clear. However, as heating manufacturers our role is to engineer for the highest possible efficiencies on each refurbishment project. Consequently, the typical modern commercial plant room will contain a number of complementary technologies in a system that has a condensing boiler at its heart.

If installing a condensing boiler is the first step in refurbishment, smart controls come a close second. Upgrading the controls is an essential part of the refurbishment with the minimum control strategy to encompass valved zone control, thermostats and timers. Further improvements can be achieved by two-zoned temperature and time control, weather compensation, and sequential control of boilers. Financially, controls achieve payback in just one to two years, according to the Carbon Trust, with a one degree lower setting bringing a reduction in an annual heating bill of up to eight per cent. Controls also create an improved working environment with greater thermal comfort for enhanced productivity.

Controls are also the key to achieving high performance from hybrid systems. With ‘bolt on’ passive energy saving technologies such as complementary LZC equipment gaining in popularity to maximise efficiencies, good integration is essential for each technology to achieve its maximum efficiencies. A building energy management system (BEMS) will fully unite and integrate the equipment, which is particularly important with hybrids using renewable technology in order to avoid any potential underperformance of the renewable equipment.

One of the most exciting and effective innovations for refurbishment projects is passive flue gas heat recovery (PFGHR) technology. It works by recovering what would otherwise be wasted energy from a condensing boiler for the benefit of cold water preheat or low temperature space heating. This allows the condensing boiler to achieve maximum full time combustion even at high flow and return temperatures and deliver more usable energy for heat. At Knauf Insulation’s offices in Cwmbran, energy and carbon were cut by two thirds, saving 74 tonnes of carbon in one year after installing ‘super condensing’ Remeha Quinta Eco Plus boilers incorporating PFGHR and adding smart controls.

Maintaining high performance

Once a system has been designed to achieve higher efficiencies, it will require regular maintenance and servicing for continued high performance. An annual service of a boiler can prevent energy increases of up to 10 per cent from soot or limescale build up. Technological advances mean that today’s boilers are easier to service. Modular boiler systems, for example, can be serviced with little to no disruption to the building users, as while one module is being serviced, the remaining boilers will ensure uninterrupted heat delivery.

Including a smart BEMS in the plant refurbishment budget will help improve future management and control of the system, allowing remote access and monitoring for 24/7 maintenance. Equally, the rise in professionals adopting Building Image Modelling (BIM) on projects also supports easier, improved maintenance. The digital information contained in the product or system file facilitates greater accuracy, indicating when replacement is necessary and encouraging high energy performance.

While refurbishment may not have the ‘Wow’ factor of new build development, raising the efficiency of our existing buildings is critical if we are to achieve our environmental targets. As manufacturers, we already offer the technology, expertise and support to achieve and maintain higher efficiencies in these older buildings. Our role now is to continue to innovate with revolutionary solutions that will achieve the maximum efficiencies for both heating and hot water delivery even on older systems. In this way, we can help the nation move closer towards our environmental targets and create a more energy-efficient, sustainable future from our past.

This article originally appeared in BSEE magazine

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