[Reduce your carbon footprint with the GB162 cascade]
Pete Mills, Technical Manager at Buderus explains how a multi boiler 'Cascade' heating system can significantly improve energy usage in commercial installations, and help towards reducing the overall carbon footprint of a building.
Energy efficiency is not just applicable to domestic boilers, although there has been a great deal of emphasis on this sector during the past 12 months. Boilers for commercial applications from offices and public buildings to hospitals, schools and colleges, residential homes and leisure centres also come under the auspices of the Building Regulations Part L and play a significant part in the successful implementation of the EPBD. This brings into sharp focus the environmental impact of new and existing heating systems, and means companies and owners of commercial properties are increasingly looking to improve or upgrade their boiler rooms to maximise energy efficiency, minimise carbon emmissions and maintain the value of the building stock.
A relatively new development in heating technology is the use of a cascade or multi-boiler system. In a cascade system, output can be precisely controlled to match heating demand and so individual boilers will only come into operation when the system demand is high enough.
Cascade systems adapt particularly well to seasonal temperature changes. Summer and winter heat output can be adjusted to match the required heat load by using, for example in a six boiler system, one boiler operating at full condensing efficiency during summer months for the hot water demand only, and with all six boilers operating together at maximum efficiency levels in the depths of winter to meet the full heating and hot water demand. The actual number of boilers brought into use during the course of the year depends on the demands at the time and is automatically controlled to ensure the most efficient operation at all times. The addition of Buderus controls will also allow a cascade heating system to be configured so that different zones can be operated with mixed temperature circuits and hot water priority.
System operation is simple. When central heating or domestic hot water is required, one boiler will start up and operate at the most efficient boiler output level. When the system requires additional capacity the second boiler will start up also operating at maximum efficiency. Additional boilers are brought in to use working on the same maximum efficiency principle until all boilers in the Cascade system are operating ensuring that the system always finds its most ideal efficient mode of operation.
The newly introduced GB162 from Buderus has been designed specifically for buildings requiring a modern, ultra efficient heating system. The GB162 is stylish, space saving wall hung gas-condensing boiler with an extremely efficient aluminium silicate heat exchanger. The GB162 is available individually in either 80kW or 100kW outputs. It is especially suited for use in cascade form, typically linking together two or four boilers, but six, eight or more boiler combinations are possible when demand for high heat outputs are required.
In fact, the cascade system brings into question the feasibility of constructing large-scale boiler rooms which take up valuable space that could be better used for storage or working areas.
GB162 Cascade systems are extremely versatile and allow the specifier a great deal of flexibility in designing a new or replacement heating system as boilers can be installed back-to-back, using a simple frame, or in-line. This is especially useful when boiler rooms are small or of an unusual shape. Boilers are lightweight at only 70kg each making transportation easy, and have very small footprint making a cascade system an excellent choice for heating system renewal, especially if space is at a premium. For example, a 400kW back-to-back 4 boiler cascade can be installed in just 1m2 of floor space. It offers flexible fluing options to make heating system planning easier, and incorporates a highly efficient Energy Management control system to maximise energy efficiency and minimise harmful emissions. The boilers are also extremely quiet in operation, thanks to a number of acoustic insulation measures and the low resistance on water flowing through the boiler. This allows cascades to be installed in close proximity to living or working areas if necessary.
Optimum heating performance is achieved by the use of large heat exchanger surfaces which encourage the condensing process and maximise energy usage. This means the boiler can remain in condensing mode all year round with systems designed at 70-50oC.
Installation is straight forward too. A cascade connection kit and pump group with modulating pump is supplied complete with all the necessary fittings and accessories so the installer simply builds the framework and joins everything together. A quick and easy job. After installation everything fits perfectly, all pipework is tidy and the boilers are ready to be connected to the main heating system. Buderus have designed the GB162 so that no minimum flow rate is required and so this reduces the need for additional system monitoring equipment. This measures further simplifies installation, and can mean electricity consumption is reduced by up to 40% in some cases.
