Got a story? Ring us on 01732 748041 or e-mail twood@unity-media.com BOILERS,SERVICING&PARTS Creating the ideal configuration Nu-Heat’s Andrew Grimsley explains what you need to know about combining boilers with solar thermal... Most conventional boilers are compatible with solar water heating, but they will always need to be linked to a cylinder with a dedicated solar volume. As a competent installer, you will probably want to start by assessing the home and recommending the best setup to meet your customer’s needs. The level of change depends on whether the solar installation is part of an upgrade to the overall heating and domestic hot water system, or is an addition to the existing system. In both scenarios, a twin-coil cylinder will be needed. The most important thing to manage is the conflict between the two heat sources. It is obviously beneficial to ensure that water is heated by means of the low carbon solar collectors whenever possible before resorting to the boiler, which is less efficient. BRITISH WEATHER Of course, the good old British weather has an impact on the ability of the solar collectors to produce hot water when needed. Points to consider include: • Most households have fairly consistent and predictable patterns of hot water usage; we usually need hot water in the mornings and evenings, whereas the solar collectors can only generate hot water when the sun is shining • The benefit of a twin-coil cylinder with dedicated solar volume is that solar energy can be used to heat a certain proportion of the requirement • Efficiency can be improved further if the boiler is timed not to fire at times of the day when the solar system is likely to be able to contribute, and the demand for hot water is low – for example during the daytime if the house is unoccupied. Equally the cylinder thermostat setting can be used to aid overall efficiency if it is set lower than the maximum solar temperature. Inevitably, there will be times when the system has to make use of the boiler but timing the system to make best use of any available solar gain will always be of benefit. This also explains why it would be difficult to provide any interlock between the solar controller and the boiler. You may be able to predict the hot water usage, but generally you will not be able to predict when it will be sunny enough to heat all the hot water needed. The boiler is, though, still interlocked with the cylinder in line with Part L of the Building Regulations. If you are selling the benefits of solar thermal WWW.HPMMAG.COM Solar thermal provides year-round hot water - up to 60% of the typical family’s hot water requirements to your customers there are some key points that are worth mentioning: • Energy efficient renewable technology which helps to protect the environment • Typical savings of 230kg carbon dioxide (CO2)/year on gas only domestic hot water (DHW) & 510kg CO2/year on electric only DHW* • Year-round hot water - it produces up to 60% of the typical family’s hot water requirements • Suitable for most types of home - retrofit or new build • Simple, reliable technology - tried and tested • Any roof type - in-roof, on-roof and frame-mounted models available • Low-cost investment - with immediate benefits • Quick and easy to install - no major building works involved • Eligible for a Renewable Heat Premium Payment (RHPP) of £600 (subject to meeting conditions) • Included in the proposed Renewable Heating Incentive (RHI) scheme Obviously, the last two points will be a big influence on whether a homeowner would choose solar thermal, so it is worth any installer working in this market taking the time to understand the basics of how the RHPP and RHI work and the steps they will have to take to ensure the installation is eligible. This would include ensuring that the solar system is Microgeneration Certification Scheme (MCS) approved and either the installer being MCS approved or getting the installation signed off by someone who is. Nu-Heat offers a MCS support package that reduces the amount of paperwork associated with MCS applications. This includes: installation manuals, bespoke mechanical and electrical drawings, full heat loss calculations, customer energy summary document and star rating, full commissioning documentation, product warranty certificates, heath & safety information and customer user manuals. SOLAR SYSTEMS CONTROL An important aspect of the solar system’s efficiency is its control system; in most cases an integrated solar pumping station with simple-to-operate controls accurately measures the temperature of the roof panels ensuring that free energy is harvested whenever the hot water cylinder can accept it. With a full assessment of the property and an understanding of the mechanical/electrical setup required in order to work efficiently, you will be able to make an ethical and cost effective recommendation to your customer. A homeowner with a well-installed system that does exactly what was promised in terms of performance is far more likely to use your services again and also to recommend you to friends and colleagues as a trusted professional. After all, we all know that the best form of promotion is word of mouth, so why shouldn’t you benefit from your hard work and expertise? *Figures from the Energy Savings Trust 64 DECEMBER 2013 HEATING & PLUMBING MONTHLY enquiry number 167
HPM December 2013
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