Water heating Efficiency
Brimming over with solutions
As water heating becomes increasingly important in the energy performance of buildings, system providers are looking to offer greener products. Ian Vallely looks at recent developments
I
nsulation and air-tightness levels in many buildings are improving. Consequently, space heating loads are dropping and hot water is becoming the dominant load.
Alan Clarke, technical support manager of Heatrae
Sadia Heating, puts it this way: ‘As buildings become more thermally efficient, their heating requirements decline. However, hot water usage will remain more or less constant and, as a percentage of the overall energy use in the building, it will go up. That means water heating will have far more focus in the design of the property than it has in the past.’ This, according to some industry experts, is why the
energy efficiency focus is shifting away from heating and towards hot water. It is also why Baxi Commercial is pushing heat pumps more at hot water generation than space heating, according to Yan Evans, the company’s technical director. He says: ‘We are looking especially at air source heat pumps working in conjunction with direct fired water heaters. ‘If the designer is going for Code for Sustainable
Homes Level 3, for example, or trying to get a percentage of the energy from some form of renewable technology on an office block or a hotel, it seems sensible to focus the renewables on water rather than space heating.’ The big driver in the design of water heating systems
– as in many other areas of building design – is energy efficiency, and a key piece of legislation to cover this is the Energy Related Products Framework Directive (the ErP, which replaced the Energy Using Products Directive in November last year). The EuP Directive covered products that were using energy. The new ErP Directive covers these as well as products that indirectly
affect energy use (for example, double-glazed windows and taps). Clarke says: ‘The European Commission sees this
directive as a tool to encourage people to buy more energy efficient products. So, for instance, after a period of time yet to be specified – but probably a couple of years after the directive is implemented – lower [performance] categories will be banned from the market. That will obviously push specifiers down a certain route because only certain products will be able to be specified.’ Evans believes the ErP Directive could have a bigger
impact on the industry than the 2010 changes to Part L of the Building Regulations – due to come into force in October this year – because it looks at system rather than appliance efficiency. And this, he says, presents a challenge throughout the supply chain. ‘Everybody has a part to play in system efficiency – whether it is designed correctly, installed properly, supplied appropriately and therefore whether it is controlled, integrated and operated effectively. Everybody from M&E design through to merchant has an impact on the delivery of efficiency.’ David Dutch, technical director of Ormandy Group,
also supports the principle of the ErP Directive because, he believes, it promotes the total system approach to designing building services solutions and could have a significant impact on how heating systems are put together in future. ‘The directive should deliver more integration, which
is the key to ensuring equipment operates efficiently, reliably and for the longest possible time. For example, demand for off-site fabrication is increasing as
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We are looking especially at air source heat pumps working in conjunction with direct fired water heaters
– Yan Evans
www.cibsejournal.com
April 2010 CIBSE Journal
63
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