A cascade boiler system has been installed as part of a Manchester school refurbishment. The system is making savings on running costs and has slashed greenhouse gas emissions
The government's school refurbishment programme recognises that many school buildings are in need of repair and upgrading.
One aspect requiring attention in many schools is the heating and hot-water provision. Buildings designed 30 or 40 years ago do not give the energy efficiency expected from today's heating systems. And replacement of an old, basic system with a modern, well-designed heating installation may pay for itself in real-term fuel economies in as little as five years.
A typical example where upgrading has resulted in a better, more efficient heating and hot-water system has taken place at Withington Girls School in Manchester.
In practical terms, the existing 30-year-old boilers had come to the end of their lives. Belfry Maintenance Group, which had carried out maintenance work on the system for many years, recommended replacement. It worked with the school and the Buderus technical advisory team to design a high-efficiency replacement installation.
They specified six GB162 100kW output Buderus boilers installed as a multi-boiler cascade system to maximise energy efficiency and to keep fuel bills to a minimum.
The compact size and comparatively light weight, at just 70kg, for each of the GB162 boilers makes handling easier even where access is restricted. According to Buderus, the GB162 cascade design means it is installation friendly, saving fitting time and costs.
A framework is supplied for site assembly and the boilers fitted
to it. The boiler connection kit is supplied with all the necessary fittings and accessories so the installer simply builds the framework, attaches the flow, return and gas pipe work, and connects the boilers via their individual pump groups.
The cascade system is then ready to be connected to the main heating system. Custom-fit insulation is also supplied as part of the
cascade kit to ensure heat losses are minimised.
Four GB162 boilers occupy just 1m2 of floor area and provide 400kW heat output. They can be automatically controlled to modulate, and therefore to maximise energy efficiency, for the longest possible period bringing into use extra boilers as and when it is most efficient to do so.
The Buderus GB162 is whisper quiet in operation and uses Buderus' finned aluminium heat exchanger. This has a twisted flow channel, which brings the maximum amount of water into contact with the hot interior surface of the heat exchanger, optimising heat transfer.
Fuel cost savings are expected to be anything up to 40% compared with the old system as the new, high-efficiency system modulates down to just 19kW to provide only the amount of heat needed to meet demand.
Buderus EMS (Energy Management System) intelligent controllers allow the heating and hot water to be programmed to the times when it is required. And the system is also zoned so separate areas can be heated for specific requirements.
Because of its energy efficiency, the new heating system also qualified for an interest-free loan from the Carbon Trust.
The school is pleased with the system - from capital cost operating efficiencies and minimal maintenance to savings on running costs. The reduced CO2 and NOx emission levels etc reflect the school's policies on the environment.
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