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Closing the performance gap

19th March 2018

Heating technology is evolving at a rapid rate as manufacturers continue to engineer for maximum efficiency. So why do we hear reports of systems that fail to deliver the anticipated high performance? Chris Meir, sales director at Remeha, discusses how greater involvement with manufacturers could help close the gap between anticipated and real world heating efficiencies.

According to the Carbon Trust, around 60% of UK non-domestic buildings that will be in operation in 2050 are already built. So if we are to meet our binding emissions reduction target of 80% by the same year, we need to make our commercial buildings as energy efficient as possible. And that means addressing the largest single end user of energy in these buildings – the heating.

According to government figures, space heating alone accounts for an estimated 45% of UK energy consumption and over 30% of greenhouse gas emissions. As such, it’s frequently the first recommendation for improved efficiency.

The government has sought to encourage improved efficiency in UK building stock, committing to help businesses improve their energy productivity by at least 20% by 2030. This is supported by the Energy-related Products (ErP) Directive which aims to establish minimum performance standards for space heating up to 400kW. At the same time, legislative changes aimed at reducing energy use in buildings, such as Part L2 of Building Regulations, increasingly require low carbon components to be introduced into heating system designs.

So how is the industry responding? The good news is that manufacturers are constantly innovating to provide increasingly advanced heating equipment to meet the ever-tighter efficiency and environmental criteria.

High efficiency, low carbon technologies

Take the humble boiler, a core component of the commercial plant room, whether operating as the sole provider of heat or alongside low carbon technologies to meet peak demand.

The latest series of condensing boilers have evolved to achieve near maximum efficiencies and ultra-low Class 6 NOx emissions, making them future-proofed to the impending ErP 2018 NOx requirements. Some models are now supplied with time and temperature controls as standard in addition to the complex algorithms that meet heat demand as efficiently as possible. In this way they enable improved control for long-term high performance. Certain models are also designed to operate on liquefied petroleum gas (LPG), offering a cleaner option for businesses in off-grid locations.

In commercial buildings with a high requirement for heat and hot water, condensing boilers are increasingly specified in conjunction with Combined Heat and Power (CHP), as an affordable route to energy efficient, low carbon heating. By generating heat and electricity simultaneously on site, CHP is around 30% more efficient than relying on traditional heating plant and electricity supplied solely from the grid. And pairing CHP with condensing boilers ensures that system performs to its full potential, reducing energy costs and carbon emissions generating electricity at gas prices.

Changing face of system design

Advanced heating technologies like these offer building owners and operators huge scope for financial savings and reduced emissions. So why, then, do we still hear reports of heating systems that fail to deliver the anticipated high performance and financial savings?

A key reason is that our older commercial building stock relies on dated systems that must be redesigned if they are to meet today’s more exacting standards. With previous working solutions to the new task often no longer available for reasons of compliance, this is forcing system design to evolve rapidly.

Take ErP. On refurbishment projects, the tighter requirements of ErP may well mean that like-for-like replacements are no longer possible. Instead, a switch of technology and/or fuel supply is required to a cleaner, more efficient heating alternative. This has effectively driven a move away from non-condensing to condensing boiler technology.

Similarly, on projects that incorporate low carbon technology to comply with Part L, a previously simple heating system can require an integrated multi-component design solution.

Given the growing range of equipment, designers can’t be expected to know every detail about every product. But the unfortunate result can be a gap between the potential and as-built design performance.

Avoiding the gap

So how to avoid a performance gap?

To maximise the efficiency of any heating technology, it’s important to take a holistic approach and consider how the equipment will operate within the system. This is arguably particularly relevant in refurbishment projects. Simply bolting a piece of technology on to a dated design to meet the new energy targets or legislative requirements is not an acceptable solution.

One answer might be to encourage greater involvement from manufacturers. After all, no one knows a product – and how best to optimise its performance – better than its manufacturer.

Maximising performance

Let’s consider condensing boilers. While on paper they have the potential to achieve outstandingly high efficiencies, they will only do so if installed in such a way that they can fully condense. And for full condensing to occur, the return temperature needs to be below dew point, which is normally around 54°C (for aluminium boilers).

For this reason, installing condensing boilers on older systems that are typically sized on high flow and return temperatures could present a challenge. There are of course ways around this. And if involved from the outset, manufacturers can help designers and contractors make the appropriate decisions regarding weather compensation control and radiator circuit temperatures that will maximise boiler operation.

On refurbishment projects switching to condensing boilers, good manufacturers will pay a site visit to survey the existing boiler plant, identify any potential future challenges and present the most appropriate solutions. They can also advise on fundamental design factors such as new flue arrangements, any necessary pipework modifications, or even a change of fuel source.

Equally, when it comes to hybrid systems, manufacturers can advise on best practice integration and how to maximise the performance of each component without sacrificing the efficiency of another. The hydraulic connection between CHP and condensing boilers is a case in point, as it is important to ensure low return temperatures to achieve optimum boiler and CHP efficiency.

Benefits of greater involvement

Using energy more efficiently in our buildings makes perfect business sense, avoiding unnecessarily high operational costs. At the same time, it helps meet environmental commitments while generating the more comfortable environment associated with improved wellbeing and productivity.

Arguably we already have the technology to transform the energy performance of the UK’s inefficient commercial buildings by delivering low carbon, energy efficient heating.

But to reap the full benefits, we need to avoid a performance gap – and that requires more knowledge exchange across the industry and greater sharing of best practice. At Remeha we look forward to supporting specifiers, consultants and contractors with advanced products and specialist technical knowledge to achieve optimum heat generation and create better buildings.

After all, on every level it pays to mind the gap.

ENGINEERING EFFICIENCY SINCE 1935