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Renewable & Alternative Heating 49

Rinnai +Renewables= Boosted DHW efficiency and Legionella compliance According to Chris Goggin - associate director of Rinnai UK - renewables technology paired with a continuous flow hot water heating unit can affect major efficiencies in domestic hot water provision.

We need to find ways of using current renewables technology, be it solar thermal, solar PV or heat pump technology, in a practical manner maximised by traditional fuel sources. One of the most ecological and economical methods is to design a system with primary renewable sources and supported by secondary sources such as continuous flow hot water heating. There has been pioneering products in this category - this includes solar thermal store of hot water and both flat plate and evacuated tube collectors, each with specific benefits to suit the differing design aspects and building envelope needs. Either option will provide years of low-maintenance, lowcost energy for heating water during the summer months – and beyond. Water heated by the solar panels is stored and technologically this is unlikely to come up to a workable temperature all year round, so the

boosting of the pre-heated water to the required temperature by a secondary heat source will be a requirement. With this system it will guarantee maximum solar gain whilst optimizing gas input. In this scenario a continuous flow water heater can be utilised as the secondary heat source to give the solar heated water the required boost. These are hot water heating products which are intelligent, fully modulating units, giving an output range from 56kW down to 2.27kW, and only use as much gas as is needed to bring the required volume of water to temperature. For example, if the solar panel array can only achieve a temperature of 40°C within the stored water instead of the required 60°C, and there is a demand on the system of 15 litres a minute, the fully modulating intelligent Rinnai unit will increase the temperature by the required 20°C (±1°C) whilst only using the required 21kW. If the demand drops to say 5l/min the heater will modulate down accordingly to an output 7kW.

This system is a blueprint for maximizing renewables gain. If you want to make it even more so, opt for one of Rinnai’s condensing water heaters and push the efficiencies envelope even further. Another technological advantage in using a continuous flow water heat as a booster is that you can wipe out any worries about legionella being a problem with stored water. If the store is below 60°C the Rinnai Continuous Flow Water heater always ensures that the 60°C minimum is always met, so the system will always comply with Building Regulation L8. If a secondary return system is used again there is a guarantee that the return will always be at 50° again in compliance of L8. For all-year round domestic hot water, Rinnai Infinity HE gas fired condensing continuous flow water heaters are supplied renewables-ready and are also easily retrofitable with current renewable technology. Rinnai’s award-winning renewable water heating solutions are designed to

offer a perfect blend of eco-friendly technologies, guaranteed to provide a constant flow of hot water 365 days of the year. The pairing of a Rinnai Infinity unit with renewables technology really is the perfect fit for a never ending DHW supply. Rinnai’s expert team is available to help with the design, specification and installation of a renewables heating system. For more information on the RINNAI product range visit ENQUIRY-Card 577


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