NOx On Effect

A major contributing factor to poor air quality, nitrogen oxides are a group of gases that are mainly formed during the combustion of fossil fuels. The dominant portion of these gases is nitric oxide (NO) which in turn can react with other gases in the atmosphere to form nitrogen dioxide (NO) the most toxicologically significant of the nitrogen oxides.  These reactions take place very quickly and are reversible, so the two gases are referred to together as NOx. Short-term exposure to concentrations of NO can cause lung irritation and respiratory infections, but medical studies have also linked the gas to cancer, asthma, strokes, and heart disease. In addition, NOx can cause changes to the environment, so consideration should be given to its control as part of your organisation’s sustainability activities.

Typically, a by-product of the combustion of hydrocarbon fuels, it is especially problematic in city centres due to idling traffic. In large parts of the UK, the atmospheric levels of NO are considerably higher than European legal limits and the Royal College of Physicians believe it directly leads to as many as 40,000 deaths each year with an estimated cost to the country of £20 billion in healthcare and lost working days.

Critically as greater political and legal weight is brought to bear on addressing climate change it is worth remembering that nitrogen oxides also act as precursors for the formation of ozone, which is not only damaging to health but has adverse effects on the environment through oxidative damage to vegetation. Introduction of N to the environment both directly as a gas and in precipitation can also change soil chemistry and affect biodiversity.

This has led to widespread recognition that more needs to be done to address the issue of NOx, from transport to energy production, distribution, and consumption in buildings.

Traditional energy generation by coal, gas and oil-fired power stations comes with several issues, including being NOx heavy. It, therefore, became popular to look at the alternatives: renewables which help with both carbon and NOx emissions. As such, low carbon electricity’s share of generation has risen delivering a major shift away from generation in large power stations. Since 1990, wider industrial emissions of nitrogen oxides to air have reduced by 74%, although estimates of projected emissions to 2030 suggest further action is required if we are to meet government emission reduction targets. These industrial reductions mean that most of a city’s current air pollution and NOₓ now arise from road traffic and buildings.

The most recent published annual air quality assessment providing data from 2010 until 2019, shows the UK was in compliance with commitments to current emission ceilings for nitrogen oxides. However, the UK continues to be non-compliant with the limit value placed on the annual mean NO concentration at several locations in urban areas. At these locations, it has been estimated that up to 80% of the NO concentration originates as NOx emissions from road transport. But buildings still stand as a key potential contributor to the other 20%.

Managing NOx Emissions From Commercial Properties

In 2018, the European Union’s Energy-related Products Directive (ErP) was used to begin phasing out the installation of less efficient equipment across Europe, including the UK. This would be achieved by establishing minimum performance standards for new equipment, with greater focus placed on heating and water heating performance in buildings. The new ErP directive enforcing maximum NOx emissions from boilers and water heaters which were set at 56mg/kWh for gas/liquefied petroleum gas (LPG) and 120mg/kWh for oil-fired products. At the time the EU predicted the new directive would produce a 20% reduction in energy consumption and emissions when replacing older equipment with ErP-compliant products

The drive towards net zero and the reduction of carbon in buildings is helping to further drive down NOx and where new builds are opting for heat pump and direct electric hot water and heating applications gas to the premises is excised. So no gas, no flues, no NOx. Refurbishing existing properties is more complicated, with low-temperature Air Source Heat Pump (ASHP) based systems typically unable to efficiently address demands. Under these scenarios, a combination of solar thermal and gas top-up for water heating is preferable and leaves sites futureproofed for next-generation green gas technologies. Realistically hydrogen grid connectivity is unlikely for the majority of the UK until the mid-2030s at the earliest, so attention needs to be applied to how gas-based systems can be optimised now to reduce emissions to levels even lower than those established under the ErP directive.

To improve combustion efficiency, condensing gas water heaters and boilers operate so that the water vapor in the exhaust – which contains about 464 kJ/kg of latent energy – condenses on the heat exchanger and not in the flue or outside the building. Designed so that the highest efficiency is at the low end of the firing range, condensing boilers typically operate at 94-95% combustion efficiency. Correctly sized and professionally commissioned, a cascade system for larger demands with high-efficiency pre-mix burners provides a high 1:20 modulation ratio. This large modulation range, along with built-in cascade control ensures that efficiencies are maximised no matter the heating load of the building. With the input of the appliance easily altered to closely match the load, the system is better able to derive as much heat out of the exhaust gases as possible.

With a high-efficiency pre-mix Fecralloy burner, such as employed in the Adveco MD & AD product ranges, ideal combustion efficiency can now be achieved of up to 107% (net)/98% (gross) reducing energy costs and producing ultra-low emissions. The low CO (19ppm) and NOx (27mg/kWh) emissions, from a hot water system built around a high efficiency condensing water heater or boiler (Class 6 appliance) easily satisfy the requirements of the current Energy-related Products (ErP) directive.

In the drive to achieve net zero, and control dangerous emissions, there remains a clear need to address legacy ‘dirty’ buildings. Currently ignored in terms of mandated policy or government support, commercial building refurbishment represents a core challenge for the UK’s climate future. Organisations looking to make steps towards a more environmentally friendly built environment may initially reject any fossil fuel-based option, but the reality is modern systems are advantageous both economically and environmentally and they bridge towards more enveloping carbon neutral and renewable options. If your building’s hot water or heating system predates 2018 then there are advantages to be gained from switching to the latest generation of gas-fired water heaters and boilers, if your system is closer to 15 or 20 years old then you really should be giving serious thought to upgrading appliances. The addition of solar thermal preheat is then going to take your system to the next level in terms of cost and carbon reduction into the 2030s and beyond.

Forward For 2022

As we look forward for 2022, Greg Brushett, Adveco’s UK Sales Manager, highlights recent product innovation and how as a business we are focussing efforts on supporting customers to navigate toward a more sustainable future for their buildings…

Adveco Ltd is an industry-leading company, which was established in October 1971. Renowned as specialists in commercial hot water, heating and low carbon applications, the company develops, manufactures and supplies technologies, applications and systems.

“We work with consultants, specifiers and designers, providing informed support and partnership through our application engineering team to design and deliver systems optimised to be highly efficient and cost-effective. For contractors, we offer a single, versatile, specialist sales resource that ensures delivery of the most cost-effective system. Facility and energy managers are supported through product remote monitoring, technical support, warranty and maintenance service to ensure system longevity and help realise low total cost of ownership.”

Stated Greg Brushett, UK Sales Manager.

Anchoring Adveco’s sustainability push forward for 2022 is a full range of commercial gas and electric water heaters, boilers, and solar thermal systems, versatile buffers, thermal storage, heat recovery and Air Source Heat Pumps (ASHP).

R32 commercial Air Source Heat Pump (ASHP). The Adveco FPi32 is a range of compact monobloc design 6, 9 & 12 kW air to water heat pumps providing hot water at 55°C, or higher in hybrid systems. The FPi32 range leverages R32 refrigerant to enhance year-round efficiency (COP as high as 5.23) while reducing the global warming potential (GWP), thereby lowing environmental impact.

“The use of R32 refrigerant has major implications in terms of taking us toward responsible, sustainable systems that deliver business-critical hot water without harming the environment,”

explained Greg.

Packaged plant room and ASHP. Designed and built offsite and delivered ready for rapid installation when space is at a premium, the Adveco Packaged e32-Hot Water System provides a pre-sized, resilient, environmentally friendly, low carbon hot water system that utilises the FPi32-9 ASHP to help offset up to 70% of the energy requirements. This compact weatherproof GRP structure provides a complete all-electric hot water plant room which demonstrates a 47% reduction in energy demands and CO² emissions for the same output of 500,000 litres of hot water each year when compared with a similar direct electric-only system.

Placing the utmost importance on customer satisfaction, the company not only supplies its range of off the shelf products, Adveco specialises in providing a bespoke solution for its customers. Providing a tailored, individually designed solution ensures that each application/system is correctly sized to make optimal product recommendations, and then supplied with manufacturer grade after-sales support.

“We choose or design products to be as highly efficient as possible, reducing operational costs and cutting or completely removing harmful CO and Noₓ emissions. Both are a critical requirement for organisations, CO especially as they strive to introduce greater sustainability on the route to achieving net-zero.”

Mentioned Greg.

In terms of recent developments, Adveco released its new range of stainless-steel high-pressure indirect water heaters and storage tanks for applications in UK soft water areas; the Adveco ATSI, ATST, ATSH, ATSR and ATSB ranges. These vessels are available up to 1000L and are all rated to 10 bar as standard.

HR001 heat recovery unit. Our latest offering is the FUSION FPH-S range of low carbon, all-electric, packaged hybrid hot water systems. FUSION harnesses Adveco’s FPi32 Air Source Heat Pumps (ASHP), a high-pressure ATSH calorifier with electric immersion, controls, and metering to provide a reliable, high-temperature, sustainable and cost-effective system for new commercial build and refurbishment projects.

“FUSION FPH-S range provides a single, easy to accommodate, highly effective response for organisations with small to medium basin and sink-led hot water demands”

says Greg.

“With Fusion, customers gain optimum efficiencies to lower the carbon emissions from a building project.”

As the company looks forward for 2022 it continues to celebrate its 50th anniversary, Adveco maintains a fiercely independent approach which is enabling the company to further extend its portfolio of select, high-quality products to better address the changing needs of a nation set on a path to Net Zero by 2050. Greg added,

“Unifying the business under the singular Adveco brand we are better positioned to bring together a greater choice of quality product, all backed by real-world experience and engineering excellence.”

Get in touch with Adveco today about your commercial building projects in 2022

The Path to Low Carbon Hot Water

When it comes to tracing a path to low carbon hot water, the design of applications for commercial hot water systems has remained remarkably consistent and if a building is more than ten years old it is going to be built around either a condensing gas water heater or an indirect water heater and boiler. Gas-based hot water systems were specified because this was the most cost-effective and cleanest way of producing high-temperature hot water.

In the past decade though we have seen a seismic shift in thinking driven by the wide acceptance of the harmful effects of global warming and a need to address its root causes. This solidified with the introduction of the Climate Change Act in 2008, and the subsequent drive to make the UK net zero by 2050. With the resultant closure of coal-fired power stations and increasing dependence on wind and solar, the carbon intensity of grid electricity has reduced in line with gas, which has, in turn, remained relatively static since the 1990s.

With the Government’s aggressive new Net Zero Strategy, despite similar carbon intensities for heating from either gas or electric, the latest regulations as outlined in the Heat & Buildings Strategy will deem gas systems alone to be too carbon polluting in commercial-scale buildings. So what path to low carbon hot water can you take? To decarbonise domestic hot water (DHW) applications there are currently two core technology options, air source heat pumps (ASHP) or solar thermal. Although both can provide low or zero-carbon heat, neither can fully replace an existing water heating system. Since commercial DHW systems must operate in excess of 60°C to prevent the threat of legionella, ASHP efficiency, designed to work with lower temperatures, rapidly falls away limiting supply. Solar thermal on the other hand is limited by the sun’s availability across the year, and it is worth remembering will not provide space heating either. However, both can be used as a source of preheat to reduce energy use. Both will work equally well with after heat provided by either gas or direct electricity.

Choosing the right path to low carbon hot water for your building

For buildings already on gas and that rely on large amounts of DHW – a large proportion of current commercial UK properties – solar preheat is the preferable option. Depending on the site and energy consumption habits, solar thermal will typically provide around 30% of the hot water demand.

For new build properties, the expectation is for specification to default to a mixture of heat pumps and direct electric afterheat. For new commercial builds, consultants are specifying for greater electrical load to account for the additional power demands. This though is a costly addition for legacy properties wanting to introduce electrification for higher demands of hot water and heating.

The electrification of buildings is the most common vision, and one the Government is driving with its aggressive target to achieve 600,000 new heat pump installations every year by 2028. Many of these will be for domestic properties, but a considerable proportion will be expected to be introduced via commercial projects. New DHW systems will predominantly follow this model, taking advantage of heat pump performance efficiencies to create a hybrid approach to deliver pre-heating for as much as 75% of the water in a direct electric system. And with no gas to the building, no local generation of NOₓ and no flue to install this clearly has its advantages. This is certainly why the government is championing this technology as the preferred path to low carbon hot water and heating.

However, this approach does not factor in running costs.  While the grid may have reduced its carbon, its cost per kWh has risen consistently over the past two decades. Gas prices on the other hand have remained essentially static until the latter quarter of 2021.  Of course, a proportion of the grid electricity is still generated by gas-fired power stations, so electricity charges also spike in response to any upward fluctuation in gas price. Despite the ASHP performance efficiencies, this has meant the running costs still increase approximately three times due to the difference in current gas/electric prices. For smaller hot water demands in new builds, where the need for a gas supply has been avoided, that additional cost may be acceptable. And we certainly see larger organisations faced with ESOS audits and SECR reporting be willing to absorb the increased running costs to introduce sustainability into their properties as a part of their corporate net zero policy.

Commercial sites with existing gas should really look at continuing to use it. Ten years ago, it was very difficult to argue for introducing solar thermal because the numbers really did not stack up against the price of gas. The capital costs of installation and maintenance versus the operational savings meant many early projects failed to recoup their investment, even with the support of RHI.

Today we are in a very different situation, and if electrical costs can be offset, then the numbers really start to look favourable for adopting solar thermal. A ten-year return on investment becomes very achievable and the property gains undisputed carbon and cost savings. Additionally, the current generation of condensing gas water heaters incorporate features such as flow regulation to automatically optimise the supplied output from the heat exchangers ensuring maximum efficiency. Models with multiple integrated heat exchangers offer load balancing for optimal long-life operation and inbuilt redundancy guaranteeing continuity of service. Those offering titanium-stabilised stainless-steel construction are also highly resilient; meaning warranties on the heat exchanger and burner components can be as much as a decade and operational lifespan should easily be 15+ years. That places replacement well into the early to mid-2030s and that is important because it means gas infrastructure remains in place for adaption to the next generation of hydrogen-based gas supply. The Government expects this will be a core component for meeting net zero at a national level, especially for buildings with higher energy demands. With hydrogen policy to be confirmed in 2026, retaining gas in existing commercial buildings keeps options open and future-proofs a building for other emerging heating technologies.

While we must all recognise the importance of excluding fossil fuels from future commercial systems and advocate all-electric systems for new builds, it is important to understand the implicit costs and difficulties of retrofit and replacement of systems throughout the thousands of legacy commercial buildings that define the UK’s urban landscape. The hybrid approach is unavoidable for commercial projects seeking a path to low carbon hot water and is the most sensible, practical, and cost-effective option. Whether all-electric or using gas after heat, commercial organisations can actively drive sustainability and retain control of operational expenditure for decades to come.