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HPM November 2015

Got a story? Ring us on 01732 748041 or e-mail twood@unity-media.com WATERHEATING,TANKS&CYLINDERS The rise of hot water storage systems Trevor Cross, specification sales director at Kingspan Environmental, says, as a result of the latest efficiency legislation, the devil is in the detail when it comes to comparing the quality and performance of unvented hot water cylinders... Hot water storage systems make up 70% of the total UK water heating market, which after a volatile period from 2010 to 2012, has settled in the better economic climate with an estimated value of £161 million. The latest industry forecast is for six to seven per cent growth by 2019. Despite a significant growth in the number of households without a hot water storage cylinder, driven by the combi boiler revolution, the number of households with unvented cylinders has grown steadily since 1997 and is now estimated at over four million homes. The growth of both non-storage solutions and unvented systems has seen a commensurate decline in vented systems, therefore, doing away with space hungry copper cylinders and cold water tanks. FUTURE PERFORMANCE The future performance of the UK domestic hot water heating market is heavily dependent on house building and construction. Other influences will be repair, maintenance and improvement activity, which in turn is affected by levels of disposable income, patterns of hot water consumption and niche market drivers such as the self-build market, which widely uses renewable energy. One of the most positive influences on this WWW.HPMMAG.COM market is the concern about energy efficiency and a greener environment. Despite the present government’s vacillation over targets and incentives, the accumulated environmental legislation over recent years within the UK and from Europe, has placed greater emphasis on carbon emissions and fuel efficiency which is shaping the future of the water heating market. As a result, manufacturers are having to respond with high efficiency features and cost saving benefits in the design and production of cylinders. The Energy related Products Directive is generally seen as a good thing that will add value to the market in terms of the necessary product improvements. Similarly, the SAP scorecard for new dwellings means housebuilders are constantly looking for low energy benefits. In fact, most of the energy efficiency measures and initiatives will have a positive impact as homeowners and businesses seek more energy efficient water heating products. With housing trends showing an increase in smaller properties and apartments, housebuilders and developers have been opting for space saving combination boilers to provide hot water on demand. However, the march of the combi boiler is slowing as its limitations for larger properties become an important consideration in the hot water system specification process. The number of homes with some sort of hot water storage is currently estimated to be around 45% of the total housing stock (approximately 12 million homes). It is paramount that the hot water system specification takes into account not only the number of bathrooms and shower applications, but also a calculation of household water usage. As well as having a shorter working lifecycle, combis will struggle with high hot water demand and especially simultaneous use of baths, showers and basins. Many new homes will now have an indirect unvented storage cylinder installed as standard because of higher levels of domestic hot water consumption. Housebuilders are recognising the lifestyle demand for high performance showering and multi-bathroom properties. Of course, the use of renewable energy sources, such as solar thermal, is also driving requirement for unvented hot water storage cylinders with twin or even triple coils. As installers become more familiar with the new technologies, and pressurised hot water systems in general, the solar cylinder models will be used increasingly as 84 NOVEMBER 2015 HEATING & PLUMBING MONTHLY part of a future proof domestic system upgrade, particularly in larger homes and properties that are being extended. With the value of energy efficiency now added to the ‘givens’ of reliability and ease of installation, it’s clear that not all unvented cylinders are the same. As well as selecting the right size and capacity to do the job, the engineering quality and performance data now merits serious scrutiny. Every component and design feature can represent a potential heat loss point or leak path, so it pays to evaluate the integrity of the cylinder before installation. INSULATION PROFILE Firstly, the best hot water systems will minimise standing heat loss to optimise the value of the energy used. This primarily depends upon the cylinder’s insulation profile, for example, materials and thickness. It’s unusual to get the heat loss down below 1 kWh/24hr, but the lower the heat loss rating the more energy efficient the cylinder becomes. A standard insulation thickness will be anything from 35mm to 50mm so an insulation lining over 50mm is a guarantee of excellent heat retention. This should not, however, compromise the ability to manoeuvre the cylinder into the available space, so size and weight are a consideration. Specifiers should look for space saving design elements and features that make a difference to the practicalities of installation, such as integral hand holds. The hot water outlet is traditionally placed at the top of the cylinder, but when it is moved to the side from the top, the cylinder is not only completely insulated, further reducing heat loss, but also easier to connect and service. A major consideration for unvented cylinders has always been the external positioning of the wall mounted expansion vessel, but the best product design incorporates an expansion space inside the cylinder, which again improves the thermal performance and makes installation quicker. Design innovation is quite rare when it comes to hot water cylinders, but the new legislative environment is placing greater responsibility on manufacturers to deliver better product performance and easier installation. In turn, specifiers need to know and weigh up all the features and benefits in order to satisfy the relevant technical and lifestyle priorities. enquiry number 142 Kingspan’s Tribune Xe cylinder is designed to heat up quickly and retain its heat for long periods


HPM November 2015
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