Solar heating
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Exploration of the solar system
Thermal stores create heating versatility by allowing you to manage the difference in time between when heat is generated and when it is required. Richard Hanson-Graville, technical manager at Thermal Integration explains
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iming is everything when it comes to heating and hot water. Heating a room on a scorching hot day is clearly nonsensical and keeping the
room temperature uncomfortably low while snow falls outside is absurd. But the gap between energy supply and demand is often very real, especially when it comes to renewables. Wood burners, for example, take some time to get going and can carry on heating a room well into the night while everybody is tucked up in bed when, in fact, the heat is often required first thing in the morning. And other renewables are not immune from this
problem. Solar input is highest during the middle of the day when hot water demand tends to be at its maximum at the start and end of the day. And, although solar panels can generate heat efficiently and cleanly, they can only do so when the sun is shining. Producing heat when it is inappropriate to do so is
worse than useless. This is where thermal stores come in because they have the power effectively to ‘time-shift’ the demand for heating and hot water. Thermal storage effectively bridges the time-gap between availability and usage by smoothing out the peaks and troughs in demand for renewable energy. It can work on a large or small scale, supplying everything from complex community projects in the form of district heating schemes to acting as buffering systems for individual homes. A thermal store is essentially a cylinder with a
heat exchanger that can feed the heating and hot water systems. (It ‘stockpiles’ thermal energy rather than simply storing domestic hot water). A thermal store can contain one or more heat exchangers, usually in the form of internal coiled pipes or external flat-plate heat exchangers. It may also include an electrical heating element. It can ‘mix and match’ different renewables such as wood-fueled biomass boilers, heat pumps, and solar water heating systems, working either with an individual heat generating source or a combination of renewable heating sources. It can also be used as a conventional boiler or immersion heater. At their most basic, thermal stores act as a buffer
system purely for central heating. However, they can also incorporate a plate heat exchanger to generate mains pressure hot water to run multiple bathrooms
34 May 2018
Thermal stores bridge the time-gap between availability and usage by smoothing out the peaks and troughs in demand for renewable energy
using high pressure mains water, without the need for unvented certification or annual maintenance. Other options provide fitted controls for the use of
boilers of all types (sealed and vented) as well as heat pumps. Control options include pump assemblies, thermostats, programmers and timers, and control valves. Both radiators and underfloor heating can be run simultaneously with a thermal store and it is
configured in such a way that low temperature loads (such as underfloor heating) can run off low temperature heat sources (a heat pump, for example) while high temperature loads (typically radiators) use higher temperature heat sources (like wood burners or boilers). The range of thermal store options is almost limitless and includes a choice of sizes, heating loads, methods of recovery, types of frame and cladding, heat metering, billing options, multiple heating zones, underfloor heating controls, and more. Because of all these options, however, it’s well worth talking to an expert to determine the best technology/technology mix for a project’s particular needs. We are always happy to provide free advice and system design.
WHY THERMAL STORES MAKE GOOD SENSE
hermal stores enable installers to integrate renewables to maximise efficiency, but that’s not their only benefit. Thermal stores provide both space heating and mains pressure hot water by storing and managing heat distribution from both traditional and renewable heat sources. They work particularly well with biomass
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boilers, heat pumps and solar water heating systems, and can be used with an individual renewable heating technology or to combine different renewable options. A thermal store used in conjunction with
renewables will futureproof a property against any future decisions to add more renewables because the householder won’t have to rip out
what’s already there and start all over again. A correctly configured, well-built thermal
store can slash running costs by 10%. Because they are open vented, thermal
stores require no temperature or pressure relief valve discharge pipework. Typically, they are factory fitted with all the accessories and connections required, making them fast and simple to install. Thermal stores can not only be made as cylinders of virtually any height and diameter, but they can also be made as tanks, designed to fit into specified clearances. The clever use of thermostats allows water heated up in a thermal store to be managed to match demand.
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