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HPM August 2013

Got a story? Ring us on 01732 748041 or e-mail twood@unity-media.com RENEWABLES Renewable water heating looking good As renewable hot water heating and storage products continue to evolve, there are a number of factors for installers to consider. Gareth Ash, product manager at Ariston, looks at how developments in legislation, incentives, and green technology will affect the future of water heating... 2013 should be the year that renewable technologies firmly establish their place on the water heating map. The Green Deal was launched in January, with the intention of funding energy saving measures to reduce energy consumption without any upfront costs to property owners. Indeed, the government is aiming to lower costs and energy demands for 14 million homes by 2020. As part of this reduction drive, initiatives have been put in place to encourage the application of renewable technologies. Commercial installations are benefitting from the Renewable Heat Incentive, which can see end users receiving a tariff, depending on the amount of measured heat provided as a result. LONG-TERM FINANCE In the interim, the government has attempted to bridge the gap by extending the Renewable Heat Premium Payment scheme until the end of March 2014. This allows money to be applied to offset the cost of renewable technologies, including solar thermal panels and heat pumps. These payments are for a fixed sum, depending on the products chosen. In addition, a number of renewable technologies are ‘eligible measures’ under the Green Deal. So, there are many benefits and rewards available for combining renewables and domestic hot water (DHW), provided that it has been specified and installed correctly, of course. But considering the many types of renewable water heating products available, what should installers be fitting for the provision of DHW? The method of water heating used within a property will depend upon whether it is located in an on or off-gas area. While the majority of UK households do have access to mains gas, there are still an estimated four million households off the grid and consequently limited to a choice of oil, LPG, solid fuel, or electric. An All-Party Parliamentary Group report on Off-Gas Grid revealed in March 2013 that a typical off-gas family faces fuel bills up to 120% higher than a mains gas user. So, it’s important for installers to fit cost effective systems where possible. One such system comes in the form of electric water heating, which offers high levels of controllability and reliability. Utilising floor-standing, direct unvented cylinders, for example, results in water being heated via an electric immersion; this, in turn, reduces energy WWW.HPMMAG.COM losses that can be experienced from pipework of a centrally heated system, as well as circulating pumps. However, to ensure optimum efficiency, it’s important that they are sized correctly. A 150-litre capacity water heater or hot water cylinder is usually sufficient to satisfy the requirements of a three bedroom house. Another technology that is already common throughout Europe is the heat pump water heater, with thousands of units being fitted during 2012 alone. The combination of a cylinder with an integrated heat pump, using an external duct to capture the heat from the ambient air, results in a Coefficient of Performance of 2.8. More impressively, heat pump water heaters can also deliver energy savings of up to 75% when compared to regular electric hot water storage cylinders. Of course, in areas of the UK where gas is available, the method of hot water supply is, more often than not, predetermined by the choice of central heating system. Additionally, hot water requirements tend to vary depending 40 AUGUST 2013 HEATING & PLUMBING MONTHLY on usage – rather than factors such as boiler location, cost and ease of installation. While there is an array of water heating systems on the market, there are really only two main types: instantaneous water heating and hot water storage. While the traditional gas boiler remains a stalwart of water heating, renewable technologies, particularly solar, are becoming more prominent, especially given the government incentives alluded to earlier. When it comes to solar, installers will find it useful if they are able to recommend a compatible cylinder. Many solar thermal panels can be used with an existing water system or as part of a new installation in combination with an indirect or twin coil cylinder. Following changes to Part L in 2010, cylinders are now more highly insulated to reduce heat loss; those offered by Ariston have achieved Energy Saving Trust Recommended status. The regulations specify that provisions should be made for the conservation of fuel and power, so that greater efficiencies can be achieved. The advanced technology in cylinders enables a dual heat source application utilising the solar panels with one coil, and the boiler with the other coil. This provides an opportunity to improve performance capability, when integrated into a renewable or low carbon system. SECONDARY HEAT SOURCE However, if an end user’s primary heat source is electric, there will be no boiler to serve the top coil. In cases like these, a single coil cylinder should be used, which sees an electric immersion heater used as the primary means of heating the water, while the single coil is connected to the solar thermal system as a secondary heat source. In light of the numerous government incentives and emissions targets, the future certainly looks bright for renewable water heating. Yet with such a plethora of options available to installers, it’s important they fully understand the wide range of technologies out there and get trained accordingly. Manufacturers need to keep installers up-to-date with the latest product innovations, which will enable them to fit the right products for the right applications, as well as provide their customers with value for money. Indeed, by continuing to develop new, alternative technologies, the combination of renewables and DHW will remain a winning one for many years to come. enquiry number 131 Heat pump water heaters, such as the NUOS from Ariston, are growing in popularity in the UK


HPM August 2013
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