Meeting new EU targets

Published: 05 March, 2014

Farley Junior School in Luton has seen energy consumption fall by nearly 60% to 273 MWh a year following the installation of Remeha Quinta Pro condensing boilers on a cascade system, low-temperature radiators and fan heaters in an installation designed by VSWR. Carbon savings are around 53 t a year.

Following the EU announcement of an emissions reduction target of 40% by 2030, Mark Northcott discusses how businesses can achieve significant, affordable reductions in harmful greenhouse-gas emissions using tried-and-tested, energy-efficient condensing and ‘super condensing’ boiler technology.

The urgent need to reduce global carbon emissions to prevent catastrophic climate change was addressed by the European Commission in January with the EU’s landmark climate deal to cut carbon emissions by 40% by 2030 against 1990 levels, the steepest climate-change target of any region in the world.

Extreme weather conditions have prevailed across the globe in recent months — linked by many, including UK Prime Minister David Cameron, to climate change. Added to this are bleak predictions of global carbon emissions reaching a new peak and warnings from the Intergovernmental Panel on Climate Change that the world is running out of its ‘carbon budget’, which will lead the world to 2 K warming — while climate scientist Prof. James Hansen and his team of experts argue that just a 1 K rise would cause dangerous warming effects.

Here in the UK, the Government’s response has been to set the nation a tough carbon-reduction target of 80% by 2050. Buildings are responsible for nearly half our greenhouse gas emissions, with the bulk of the problem lying not with new-build but rather the nation’s existing building stock. According to the Building Research Establishment, 60% of the buildings that will stand in 2050 are already built, with 40% of these pre-dating the introduction of Part L, which is why refurbishing them is the real challenge if we are to come anywhere near reaching our environmental commitments.

Heating and hot-water generation account for around 40% of our emissions. While ‘green’ heating is often equated with renewable technology equipment, retrofit is proven to be a practical, affordable starting point for building operators wishing to adopt carbon-cutting measures. Retrofitting a fully-modulating, high-efficiency condensing boiler is a tried-and-tested cost-effective measure that will bring about a rapid reduction in a building’s carbon footprint, energy use and fuel bills. Further, owing to the nature of the existing heating system, it is often the only possible solution. As technology has advanced, new smaller and lighter models enable easier installation and minimum disruption, while cascade and rig systems facilitate wider output modulation for optimal efficiency and greater energy and carbon savings.

The more efficiently a product operates, the lower the carbon emissions, hence the EU’s ‘indicative’ target of improving energy efficiency by 25% by 2030. Many heating manufacturers already offer boiler models with exceptionally high efficiencies of over 98% that meet the raised efficiency standards to come into force in 2015 with the new Energy-related Products (ErP) Directive. Compare this with a 10- or 15-year-old boiler and the results are outstanding; replacing an old atmospheric boiler with a clean-burning condensing boiler could slash greenhouse gas emissions by as much as 90% and halve fuel bills.

However, this is just the starting point. Smart system design is essential to minimise the potential ‘energy performance gap’ that can occur between the predicted energy consumption and carbon footprint of a building and the actual results.

The maximum efficiencies quoted by manufacturers on their condensing boilers are achieved in idealised conditions – typically at half load and low temperatures.

Most condensing boilers in the UK are simply not installed in a manner which allows them to achieve these exceptional figures.

Gas consumption at Knauf Insulation’s offices in Cwmbran have been reduced by nearly 70% to save over 387 MWh and 74 t of carbon a year since the replacement of atmospheric boilers with Remeha’s Quinta Plus ‘super-condensing’ systems.

A typical existing LTHW system will generally have been sized on high flow and return temperatures. This means that the boiler, while operating at higher efficiencies than an older model, will be prevented from fully condensing and operating at its optimum efficiencies.

To maximise an individual building’s energy- and carbon-saving potential, it is important to work with manufacturers who will share their expert knowledge of a product and its varying range of efficiencies to assist in designing the smartest heating system.

The first step is to include an allocation in the budget for renewing boiler plant for the addition of control upgrades, terminal unit replacement and passive energy-saving technologies such as flue-gas heat recovery or complementary low- and zero-carbon technologies.

Adding the appropriate control, for example, ensures that a boiler is operating at its maximum efficiency.

The minimum control strategy should encompass valved zone control, thermostats and timers. Further improvements can be achieved by 2-zoned temperature and time control, weather compensation, and sequential control of boilers. The Carbon Trust suggests that lowering set points by 1 K could reduce an annual heating bill by up to 8%.

Heating systems that incorporate passive flue-gas heat-recovery technology are particularly successful on commercial refurbishment projects as they ensure that the maximum useable waste heat is recovered from the boiler, thereby giving the highest possible efficiency irrespective of return temperatures. The recovered heat is used to preheat a cold-water feed, heat return water or simply circulate to a thermal store. The inclusion of this recovered waste heat signiﬁcantly reduces the amount of energy required for the boiler to heat the water to the required temperature, leading to major proven energy savings and emissions reduction of up to two thirds.

The high-efficiency condensing boiler will remain a key component in low-carbon energy-saving heating systems in future years. But for maximum results in carbon-emissions reduction, we must continue to innovate in system design and continue to challenge existing wisdom surrounding condensing technology. At Remeha Commercial we look forward to doing just that. Using our product knowledge and our new ‘super condensing’ technology that delivers a higher attainable level of efficiency of 107% NCV at all times and all flow and return temperatures, our aim is to support the design of smarter, Blue Efficiency systems that will help us as a nation meet our environmental targets and move towards to a low-carbon future.

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