Applying a Part L mindset to water heating

PAUL YUNNIE discusses why energy-efficient water heating can bring savings independent of those accrued by applying the latest Building Regulations for selecting boilers in commercial buildings.It is interesting to note that when reviewing original Government proposals relating to energy efficiency in heating plant for commercial buildings, very little, if anything, is mentioned about hot-water services in commercial buildings. This applies equally to the Government’s Enhanced Capital Allowance Scheme (ECA), the Conservation of Fuel and Power Building Regulations L2 (April 2002) and recent draft proposals for the control of energy consumption in commercial buildings. Dedicated It is only recently that the ECA has included a sub-section under boilers to allow condensing water heaters to be included. This is probably due to the fact that the mindset in many quarters still regards the provision of hot-water services as a by product of space-heating boilers. This is strange because, as with much of our commercial building stock, many Government buildings, including schools, hospitals, prisons and military installations, most commonly provide their hot water services from dedicated independent direct-fired water heaters. The reason why hot-water services should be treated separately from space heating is the huge change that has taken place in recent years in the building-services industry, particularly in commercial buildings. Gone are the days of large commercial boilers being fired in summer just to provide hot water. Gone are the days of central plant providing hot water across complex sites such as a university campuses or military facilities. I well remember some 20 years ago, visiting a university campus on a winter’s day and seeing a green trace-work through the snow showing the passage of pipework between buildings, indicating energy loss. Energy savings The inefficiencies of energy use through inappropriate boiler sizing and transmission losses have already been significantly reduced by the specification of dedicated direct-fired water heating, usually sited near the point of use. At the time that this transformation began, the then British Gas graphically demonstrated the energy savings that could be made in a variety of commercial and public buildings, particularly through the Gas Energy Management Awards. Another change that has occurred, driven by the Building Regulations, is that better construction methods and air-tightness testing are ensuring that the heating load is reducing whilst the hot water requirements remain at least static and therefore represent a larger proportion of the energy use of a building. We are also seeing many new buildings with water heating far outweighing the energy requirement of space heating — e.g. leisure, sports and fitness centres. It is therefore surprising that more regard is not taken of independent water heating equipment by legislators when drawing up consultative documents. Part L2 of the Building Regulations fails to take account of the significant energy saving that can be achieved by the correct sizing and application of direct-fired gas water heaters. Apart from the actual control and design of the system the regulations really only support solar water heating. Though solar water heating is available on the market it needs more development, and it is quite likely that an alternative back-up unit will be needed for large-volume applications. However, direct gas-fired water heating is available here and now and given the correct automatic controls it can satisfy the requirements of Section 1.35 in Part L2 of the Building Regulations. Much has been written in the trade press concerning the requirement to move towards condensing boilers in both the domestic and commercial arena. It is sensible therefore to consider that both legislators and building owners will expect water heating equipment to follow suit. It is therefore not surprising that a number of commercial-water-heating companies have developed and are continuing development of a variety of condensing water heaters. As has already been mentioned, provision has been made in the ECA scheme for water heaters that comply with its requirements. Fig. 1 shows the latest development of condensing storage water heaters from Andrews, but it is not the first. There are a few condensing water heaters on the market besides the storage type, including the non-storage models (Fig. 2) which are now included in the ECA list. More advances are to come to give a complete range of condensing water heaters that will play their part in providing energy efficient solutions in the UK’s commercial building stock. Statutory obligations In summary, when considering energy-saving measures, separation of the heating and hot-water load should be facilitated together with installing water heaters to the point of use where possible. This can be achieved with the wide variety of storage, non-storage and continuous-flow water heaters on the market. Further, and in the spirit of the Conservation of Fuel and Power in Part L 2 of the Building Regulations, this new pool of condensing storage and non-storage water heaters will help building developers, architects, consultants and owners to achieve their statutory obligations by efficient hot- water production and making appreciable savings on their running costs. Paul Yunnie is managing director of Andrews Water Heaters, Wednesbury One, Black Country New Road, Wednesbury, West Midlands WS10 7NZ.
He is chairman of Group 7 (Water Heaters) of ICOM Energy Association
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