Save up

Schools could save up to £21,500 a year in energy bills by improving their energy efficiency and cutting energy use, according to the Carbon Trust. With heating accounting for the greatest use of energy in schools, it is a prime starting point for efficiency measures.

With limited funds in the coffers, it makes sense to identify efficiency savings wherever possible. Given that heating alone accounts for on average 58 per cent of a school’s total energy use and is usually its most expensive user of energy, it is a logical first step for efficiency measures. Reducing energy consumption in heating will result not only in lower energy bills that will release more funds for student education, but also a lower carbon footprint that will assist local authorities in meeting their environmental commitments. Through its work with 3,000 schools over a ten-year period, the Carbon Trust has identified that schools could save up to £21,500 a year in energy bills by improving their energy efficiency and cutting energy use – in real terms, that’s the equivalent of the salary of a newly qualified teacher.

High returns on investment

A high proportion of UK schools are in old buildings, many with old heating systems in place. This factor combined by tight budgets may encourage many to favour the practical, affordable approach offered by retrofit technologies. While retrofit may not have the ‘Wow’ factor of renewable technology, it is important not to underestimate the returns such measures offer on energy efficiency investments. Replacing a 15-year-old atmospheric boiler with a modern condensing or super condensing boiler, for example, can raise efficiencies from as low as 50 per cent to over 90 per cent, slashing energy consumption and bills by more than half for rapid financial payback. They are also low in harmful NOx emissions and are proven to lower carbon emissions by up to 90 per cent.

Minimum disruption

Advances in condensing boiler design mean that retrofit projects no longer need to be restricted to the holiday period. The smaller lighter dimensions of modern condensing boilers make for faster, easier installation. Prefabricated heating systems also make boiler replacements more flexible to carry out. Condensing boilers on a cascade system, for example, are delivered on site in a pre-assembled wheeled unit for improved quality control, reduced installation time and lower labour costs. Such a system also allows the heat output demand to be matched more accurately and more reliably in a fraction of the space.

In buildings where access is particularly awkward due to its location, typically in the basement, or accessible only through narrow stairways and corridors, forward-thinking manufacturers have introduced condensing boiler models that can be disassembled into sections for faster, easier installation and reduced labour costs.

Maximising building saving potential

The UK’s existing building stock is where the challenge lies if we are to meet our carbon reduction target of 80% by 2050. In older buildings with existing heating systems in place, it is worth considering an allocation in the boiler replacement budget for passive energy saving technologies to maximise the building’s carbon and energy saving potential.

Whilst condensing boilers are capable of achieving efficiencies of around 94%, even the most efficient boilers could struggle to achieve these figures on old heating systems as they are sized on high flow and return temperatures, preventing the boiler from fully condensing. In such cases, ‘super condensing’ passive flue gas heat recovery systems could be a more efficient solution. They work by recovering otherwise wasted energy for the benefit of space heating or cold water preheat, thereby reducing the amount of energy otherwise required by the boiler to heat. ‘Super condensing’ boilers like Remeha’s Quinta Eco Plus are particularly effective on retrofit and refurbishment projects, achieving a net efficiency of 107% which has proven to slash utility bills by as much as two thirds.

Taking the renewable route

Depending on the nature of the building and the budget, adding complementary LZC technologies such as biomass boilers or heat pumps may be an option for a lower carbon footprint. Many of these technologies have the additional incentive of funding from the government’s Renewable Heat Incentive to support the initial investment. Schools using biomass boilers, for example, have received as much as £25,000 a year in RHI funds.

When retrofitting renewable technologies, it is essential firstly to calculate just how ‘green’ the product is. For example, a gas-powered heat pump not only offers the same financial benefits as an electrically-powered heat pump, but also scores higher in terms of carbon reductions. Secondly it is important to factor in at the design stage how the chosen renewable technology will work for a particular building and how it will operate with additional components in the heating system. Failure to consider the operation of the system as a whole could result in unexpectedly high operating costs when the low-carbon technology fails to perform as expected. It often pays to find the same supplier whose knowledge and expertise of the two technologies will support smarter system design.

Get in control

No matter how advanced the technology, if it is not operated correctly it will fail to deliver the maximum benefits. Adding the appropriate advanced control to a boiler ensures that it operates at its optimum efficiency level and matches the heat requirements of the building, delivering the right temperature of heat only when needed for maximum energy and carbon savings. Controls are simple to fit and use and typically achieve payback in just one to two years.

Controls are also crucial to well-designed bivalent systems, uniting the renewable and condensing technologies and optimising their combined operation. Advances in technology have brought the arrival of bespoke hybrid heating and hot water systems with their own fully-integrated building management control systems to address the energy performance gap from renewable technology due to poor system design. Remeha’s Fusion Hybrid is a bivalent system combining gas absorption heat pumps and condensing technology with a fully-integrated, scalable building management control system delivering net seasonal efficiencies of 120-130% that can be tailored to meet the individual heat requirements of a building. As the control system can be integrated where required into a building’s existing BMS, it is suitable for retrofit project as well as new build.

For schools keen to make the budget go further whilst fighting climate change, the good news is that the technology is here now for affordable energy-efficient heating. With condensing technology playing a key role in the modern boiler house mix, it is encouraging that heating manufacturers already offer modern condensing boilers with high efficiencies of 94% that meet the new ErP Directive standards to be introduced next year, advanced controls and energy and carbon saving bolt-ons. Why waste energy when you could retrofit and save?

This article originally appeared in LABM June 2014.

To find out more, email us at: boilers@remeha.co.uk

 

 



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