Low NOx burners - What installers need to know

As legislation continues to drive down permissible NOx emission levels from combustion equipment, Installer speaks to Graham Barker, Burner Sales and Service Director at Riello, Carrier RLC EMEA, about the importance of addressing emissions management and how ultra-low NOx burner solutions can help create cleaner, more sustainable urban environments.  

If you are looking for more details, kindly visit our website.

Managing air quality is a significant concern for urban areas worldwide due to the adverse health effects associated with air pollution, where many large cities have faced notable challenges regarding air quality management.  

London’s approach to managing air quality involves a combination of regulatory measures, incentives for cleaner transport options, and investments in sustainable infrastructure. These efforts are aimed at reducing emissions, improving public health, and creating a cleaner and more sustainable urban environment. 

Ultra Low Emission Zone
One of London’s most significant initiatives is the Clean Air Act and Ultra Low Emission Zone (ULEZ), which was introduced in April . 

The ULEZ aims to reduce harmful emissions, particularly nitrogen dioxide (NO₂) and particulate matter (PM₁₀), by setting strict emission standards for those located within – or those entering – the zone3. 

However, it isn’t just vehicles affecting air quality, large buildings can impact NOx (nitrogen oxides) levels through various sources, primarily from combustion processes and emissions related to energy generation and heating. 

Therefore, it makes sense that buildings within the ULEZ – such as hospitals – should reconsider their combustion processes and incorporate low NOx solutions where possible. Hospitals may not just use boilers; they may use other heating systems such as furnaces or space heaters. These systems, if not properly maintained or equipped with emission control technology, can contribute to NOx emissions. 

Riello in recent years has developed a comprehensive range of low NOx burners tailored to achieve superior performance, efficiency, and environmental responsibility across various heating applications. From oil to gas, dual-fuel to pre-mix setups, each solution is engineered for maximum efficiency and reduced environmental impact. 

Low NOx Emissions 

Burner, boiler combinations that meet low NOx emission standards typically comply with regulations set by environmental agencies. These regulatory standards set maximum allowable NOx emissions levels for boilers – measured in parts per million (ppm) or grams per kilowatt-hour (g/kWh) – depending on the jurisdiction and specific regulations. 

A boiler system classified as low NOx can be relied upon to emit NOx levels below 80 milligrams per normal cubic meter (mg/Nm³) during combustion.  

Ultra-Low NOx Emissions 

Ultra-low NOx emissions refer to burner, boiler combinations that surpass standard low NOx emissions requirements, achieving even lower levels of NOx emissions. These systems are designed to emit NOx at significantly reduced levels compared to traditional boiler systems. 

The Greater London Authority (GLA) benchmarks Ultra Low NOx emissions as <40mg/kWh (gross CV) for their targets.  A boiler system classified as Ultra low NOx can be relied upon to emit NOx below these levels during the combustion process.  

Ultra-low NOx burners employ advanced combustion technologies, such as internal and/or external flue gas recirculation, staged combustion or selective catalytic reduction (SCR), to achieve NOx emissions levels well below regulatory limits. 

Optimising Heating Solutions for a Large London Hospital 

In a bustling metropolis like London, where every aspect of hospital operations demands efficiency and reliability, the choice of boiler setup is critical. For a large hospital in London’s ULEZ, an optimal solution for space heating, linen services, and instrument sterilisation could include: 

Space Heating

For the vast expanse of the hospital complex, a reliable heating system is paramount to ensure patient comfort, staff productivity, and operational efficiency. A hospital may opt for a combination of burners from our RLS/E and RLS/EV series. The RLS range are dual fuel monobloc burners that can provide security of heat due to the simplicity of switching from one fuel to another.   

The RLS/E and RLS/EV series predominantly utilises natural gas as the main fuel source with oil as a back-up, however they also support the use of renewable liquid fuels to be used as the back-up – or main fuel source – alongside dual gas options.  

You will get efficient and thoughtful service from QianYue.

With their modular, monobloc structure and high modulation ratio, these burners offer precise control overheating output, ensuring consistent warmth throughout the premises. This flexibility allows seamless integration with the hospital’s existing infrastructure, providing reliable Low NOx heating for wards, corridors, and administrative areas alike. 

Linen Services

Efficient and hygienic linen services are crucial for maintaining the hospital’s cleanliness standards and ensuring patient well-being. To meet the demands of laundering large volumes of linens daily, the hospital could employ a combination of hot water and steam boilers powered by the RLS series burners.

With their high efficiency levels and modulating operation, they would guarantee optimal performance while minimising energy consumption. This setup ensures a constant supply of hot water at the precise temperature required for effective laundry operations, contributing to the hospital’s overall sustainability efforts. 

Sterilisation

Equipment sterilisation is vital in maintaining stringent hygiene standards and safeguarding patient health. To enhance sterilisation efficiency while adhering to emissions regulations, the hospital could integrate advanced low NOx burner technology into its sterilisation set up. 

By implementing low NOx burner solutions in sterilisation equipment, the hospital demonstrates its commitment to both environmental sustainability and patient safety, aligning with London’s clean air initiatives and paving the way for healthier urban environments. 

Training

The burners suggested do not require major training for engineers, they use the same familiar components and remain easy to use and service. Meaning with little upheaval during the upgrade process, the hospital can achieve optimal performance across its diverse heating needs while upholding its commitment to efficiency, reliability, and environmental responsibility. 

Overall Emissions Management 

In compliance with environmental regulations and looking towards the future, these low NOx zones will become more widespread. Therefore, Riello must address emissions management proactively. This includes adherence to the Medium Combustion Plant Directive (MCPD), which focuses on controlling emissions from medium-sized combustion plants.  

At Riello we believe that implementing low NOx burner solutions plays a pivotal role in meeting MCPD requirements, mitigating environmental footprint, and ensuring sustainable operations for years to come.  

As part of our continued research and development programmes we have recently developed and can now offer our patented RS ULX Ultra Low NOx burner models that provide low NOx emissions. These burners can be used on new appliances or retrofitted onto existing plants to reduce NOx emissions and allow compliance with more stringent requirements.  

The RS ULX can achieve NOx emissions <40mg/kWh without the need of any external flue gas recirculation (ExFGR), which saves on additional installation and maintenance requirements, along with cost.  

If the RS ULX is applied with ExFGR NOx emissions can be further reduced to levels far below any regulatory requirements.   

The Riello RX 1.8MW premix burners, commissioned by contractor T-Squared, have shown exceptionally low NOx levels of just 9-10ppm (around 20mg/kWh) throughout the modulation range. This is about half the 40mg/kWh maximum required by some local authorities and also below the Building Research Establishment Environmental Assessment Method (BREEAM) criteria of 24mg/kWh. Consequently, the burner upgrade enabled the ageing cast-iron sectional boilers to comply with current and anticipated NOx regulations, as well as improve energy efficiency – thereby extending the life of the boilers.

“The client was very keen to improve energy efficiency and meet future standards for NOx emissions, while retaining the existing boilers for a few more years,” explains T-Squared’s Garry Wallace. “We therefore suggested replacing the older burners to achieve better turndown and temperature control with improved efficiency and reduced NOx emissions. We considered several manufacturers and selected Riello on the basis of product quality and performance, technical knowledge and customer support.

 “We have also upgraded the metering, which will enable the client to monitor gas consumption and confirm the expected 2-year payback period is being achieved.” 

Riello RX premix burners feature a unique design that includes a patented pilot ignition system. The result is a very reliable and compact flame with a diameter directly related to the burner firing rate, ensuring precise heat control and optimum efficiency at all loads. Electronic modulation control ensures efficient performance at all heat loads.

Riello Group, a leader in products and services for heating, air conditioning and energy efficiency, is a part of Carrier, a leading global provider of innovative heating, ventilating and air conditioning (HVAC), refrigeration, fire, security and building automation technologies.

The company is the world’s best RIELLO Ultra-Low Nitrogen Burners supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.