The role of cascade systems in improving efficiency in commercial buildings

31 July 2024

The UK government’s Heat and Buildings Strategy highlights the urgent need to transform the heating landscape. Aiming for a Net Zero future by substantially reducing energy consumption in buildings by 2050 is ambitious but crucial. However for commercial premises, boilers are still very much the go-to option given the proven reliability, comfort and ease of use offered. Darran Smith, Technical Manager for Alpha, provides a comprehensive overview of the role cascade systems can play in improving boiler efficiency in commercial buildings.

Commercial premises account for approximately 20% of total heat emissions, whilst in domestic and commercial premises combined, 97% of greenhouse gas emissions come from space and water heating, with 2% from cooking.1 Given that heating in commercial and public buildings contributes 18.2 MtCO2e to UK emissions, the drive towards energy-efficient measures has never been more significant.

The challenge posed by commercial buildings is often the sheer size of the space, and therefore the output needed on the heating system to ensure effective distribution of heat. In public sector buildings especially like hospitals and schools, as well as private office blocks, the need for reliability is especially great to ensure a safe and productive environment.

The options for commercial spaces are thus follows: one large boiler responsible for powering the entire space, or several smaller boilers in cascade (connecting multiple boilers together to work as a single system) designed to achieve the same output.

Distributing the heat output across more than one unit bring many key advantages:

Improved Efficiency

  • Higher efficiency compared with the use of a single boiler of higher heat output, which will have to work under a reduced heating load for large periods of the heating cycle, with lower system efficiency.
  • Cascading allows the system to load match, thus when heating demand is lower, less boilers are required to turn on and when demand is high, more boilers are used.

Cost savings

  • Not only do smaller boilers generally have a smaller purchase price, but the operation of a cascade system can be a cost-effective solution compared to a single boiler, due to operating only the required number of boilers to meet the demand.

Redundancy and Reliability

  • Multiple boiler applications are more reliable than a single standalone boiler and can maintain the heating function even when maintenance on one of the connected appliances is required. Alpha ProTec NX boilers are designed to be very easy to service with commonality of parts.
  • Even distribution of the heating load on all the appliances, which avoids the premature deterioration of one lead boiler compared to the other.

Space Efficiency

  • The modular set up of a cascade solution offers a very flexible space saving alternative, allowing the use of wall mounted boilers where the total required output may normally only be available from larger floor standing units.

Scalability

  • If heating demand of the overall premises increases, either through building expansion or personnel changes, additional boilers can be added to the cascaded system making it easier to scale up without a complete overhaul.

Enhanced Control and Management

  • Any heating equipment, no matter how advanced, is only as effective as its controls. For large commercial facilities, especially those managing multiple climate zones or using building automation systems, controls become paramount.
  • Modern cascade systems are equipped with sophisticated controls that optimise the operation of each boiler for maximum efficiency and performance.

Ideal for commercial applications, the ProTec NX is a high-efficiency, fan-assisted condensing boiler, that provides maximum efficiency, improves running costs and offers ultra-low emissions to meet the latest building regulation and authority requirements.

Available in six individual outputs ranging from 48kW up to 180kW, the boiler range has the capability of cascading to achieve higher outputs and increase load flexibility. Its wide 1:10 modulation range enables the boiler to run at a low output with fewer on/off cycles, reducing emissions and increasing component longevity.

For installers, the ProTec NX offers an easy-to-fit unit which can be wall-mounted or fixed to a freestanding low or ultra-low frame. The range has flexible flueing options, with open flue, room sealed concentric and room sealed parallel flue options available.

The new range offers a more compact, space-saving solution, especially when banking boilers together with a range of flue options for individual, cascaded and different ventilation scenarios. A wide range of hydraulic accessories is available to link boilers, and plate exchangers and low loss headers to feed multiple heating and hot water zones.

For more information, take a look at our commercial boiler range or please contact us and a member of our team can discuss your available options.