Stefan Gautsch, design engineer for Buderus, comments on a high-efficiency boiler solution where energy efficiency and flexibility were the key requirements for a new heating installation
The specification for any heating system requires careful consideration of a number of factors to optimise heating performance and energy efficiency.

The level of emissions, annual running costs, the type of controls and initial capital outlay, including installation costs, all have a bearing on the investor's decision.

In most circumstances, for domestic dwellings, the options are straightforward as the main criteria are established under Building Regulations and SEDBUK.

The commercial sector, however, can be much more complex as requirements vary enormously from one installation to another. Almost every commercial heating system is different in some way. And so hydraulics and ancillary equipment, such as pumps and valves, all need to be correctly sized and carefully designed to meet individual needs and specific heat requirements. Special attention has to be given to the location of the boiler, access to the boiler room, positioning and age of existing radiators, routing and quality of existing pipework, use of individual rooms or zones, controllability, and more - and that's before the choice of the actual boiler itself.

To help heating system engineers determine the most economical and efficient solution for any situation, Buderus Technical Advisory Service offers help with hydraulic design, and site visits where necessary.

The efficiency of the heating system is a major consideration for any project. But it is a special priority for the public sector, which is at the forefront of implementing government policy on emissions. And it therefore has to lead by example with systems that are fuel efficient and so reduce their overall carbon footprint.

Cascades, or linked multi-boiler installations, are being seen as offering an excellent and efficient alternative to the more conventional single larger boiler, especially for buildings which have a varied pattern of usage.

The installation of a cascade system using Buderus GB162 boilers has recently been completed at St Mary's College in Blackburn, Lancashire.

After many years of simply adding to the heating system to incorporate new buildings, the need to install heating for the new £8M Science and Performing Arts centres and main building refurbishment provided an opportunity to review the complete heating provision and upgrade the existing aging boilers.

Reliability

Consultant National Design Consultancy worked together with the Buderus Technical Advisory team to provide heat and hot water with system performance and reliability key requirements.

A 400kW four-boiler cascade system, which occupies just 1m2 of floor space, was specified in a two-by-two back-to-back configuration. This was suited to its location, which had limited access. Speed of installation was important as the work needed to be completed within the summer recess.

The overhaul of the heating system involved the relocation of the main boiler house into what had previously been a smaller subsidiary boiler room described as little more than a large cupboard with an old 100kW boiler only.

This now provides the heating for the vast majority of the college and houses the four GB162 cascade installation. The previous larger boiler room is scheduled for an additional Buderus cascade system. This will satisfy a slightly smaller existing heat requirement as well as the future heating needs of the college, in a two-year staged programme.

Chris Mason of heating engineer James Boardman carried out the installation of the boilers which included replacement of 81 radiators and associated pipework. He was impressed with the cascade system. 'With such a limited time to complete this large project, everything needed to run very smoothly indeed,' he says.

'The GB162 boiler cascade system is engineered especially for speedy installation and the cascade framework went together so well it was a key factor in completing the installation on time.'

Efficiency

Controls were also an important feature to maximise efficiency of operation and therefore reduce fuel costs. James Boardman is anticipating a fuel saving of up to 25% resulting from the new installation, which also includes a new separate boiler management system to interface with the Buderus boiler controls, and which will link together the operation of both plant rooms.

The GB162 is especially installation friendly, whether fitted as a single boiler or as part of a multi-boiler cascade, saving fitting time and costs. Once the installer has constructed the freestanding framework and hung the boilers, all that remains is to connect each boiler to the main heating system.

The connection kits and optional fully insulated pump groups with temperature and pressure gauges are supplied with fittings and accessories. The GB162 is available in either 80kW or 100kW outputs and is quiet in operation allowing it to be installed close to living or working areas.