With plant rooms shrinking and space, especially in the city centre, becoming more precious and costly, reducing the size of a boiler plant can help significantly cut down costs. A modular approach not only takes up less room but can also considerably decrease carbon emissions thanks to better operating efficiencies across the installation.

How can I reduce space, costs and environmental impact of a boiler plant?

With prices in parts of London, such as e. g. the West End reaching £1,075 per m² of floor space per year for a rented office, compact heating equipment is almost a necessity.

Smaller boiler plant rooms have become common in bigger cities, calling for flexible heating solutions with high output requirements. Plant room access can also be an issue, often the only route into it is through tight stairways and narrow doorways.

Continuous product development over the last few decades has made it possible to achieve an output of 1MW with modular boiler systems from less than 1 square metre of floor space. Good news for cities, as it effectively reduces the room a boiler is taking up which can be used for other purposes. Compared to large high output (and high water content) boilers which used to deliver this kind of output, compact modular boilers benefit from a low water content and hence a quicker heat up time.

It is however not just the footprint but also the flexibility and efficiency that benefit buildings equipped with modular condensing boilers. They can be stacked on top of, or next to each other. How the boiler modules are positioned is adjustable to the room layout, especially convenient where ceilings are low. To address access issues, boiler modules are easily separable and can be moved to the place of use. Compared to larger high output boilers, the use of a crane or other expensive equipment to get the boiler into a building is not necessary, reducing cost even further. This may also remove the need for road closures, another win for city centres.

Why are modular boiler arrangements highly efficient and how can they help to reduce air pollution?

Reducing air pollution in London is high on the agenda. Efforts are being made to lower CO2 and NOx emissions. Commercial and domestic heating are significantly contributing to both kinds of emissions. With the Energy-related Products Directive introducing mandatory NOx limits for space heaters up to 400kW output from 26 September 2018, there will be a further phase out of the highest polluting equipment. But legislation is not the only driver for improving air quality.

Several boiler modules have the advantage of working at lower loads together compared to a large output boiler working at full load on its own. Correct setup helps to improve efficiencies and extend the lifetime of the products, as it ensures even use across the installation. In multiple boiler arrangements, the boilers can be set to operate in different modes.

Unison Control

In unison control, the controller attempts to hold as many boiler modules firing at the same time to match the base load of the building. The aim of this setting is to have them all modulate to more efficient low fire together.

Cascade Control

In cascade control, the controller attempts to match the base load with as few boiler modules as possible. Each method has its own merits dependent on the hydraulic configuration local to the boilers. In the case of condensing boilers, operating temperature and return temperature then come into play. Condensing boilers are most efficient when they ‘are able to’ condense. That’s why it is even more important to have a wide temperature differential with low return temperature to ensure it is operating in condensing mode (e. g. 70/40°C). 

This translates into energy savings, effectively reducing gas consumption and lowering fuel bills. Although upfront costs of modular boilers might be higher, the expenditure is relative: Floor space and fuel cost savings resulting from higher efficiency and load matching ensure a short payback period and long-term savings. 

Thanks to product improvements, the formation of thermal NOx can also be decreased significantly. This means NOx emissions below 40 mg/kWh help to achieve maximum BREEAM credits while reducing the impact of heating equipment on air quality. 

How can modular boiler installations improve heating system reliability? 

Benefits of modular boilers are not only limited to the environmental and operating cost side of things but also the reliability of a system. When a heating system runs in unison control mode, boilers are used more evenly across the installation which decreases wear and tear. Additionally, should one boiler module be serviced or cut out, others can serve as back up to ensure a continuous heat supply.

Why are multiple boiler installations a good all-round solution? 

Modular boilers are a perfect fit when it comes to finding a flexible, compact, space-saving, and energy efficient solution. They can overcome access issues in city centre plant rooms while being able to deliver a reliable heating supply, even in bigger heating systems such as heat networks. Thanks to their small footprint in terms of floor space, CO2 and NOx emissions, they effectively reduce the space needed for heating equipment while lowering their impact on the environment.

Learn how you can reap the small footprint benefits with the Upton boiler.