Solar thermal systems provide hot water for households and in somes cases can help with heating. EvoEnergy are MCS accredited installers of the technology.
A solar thermal, or solar hot water system is used to provide hot water. This water can be used for washing machines, showers, baths, dishwashers and anything else run through your storage tank. It is not generall used for radiators or general space heating.
In the simplest terms a solar thermal systems are comprised of a solar collector, a storage tank, a boiler, a pump and a controller.
The solar thermal systems supplied by Schuco are closed loop systems. This means that the fluid that passes through the solar collector never actually touches the water that you use for the washing. The fluid is silently pumped through the closed system, heated by the suns energy in the solar collectors and then passed through a heating coil in your storage tank. This transfers the heat contained in the fluid to the water in the storage tank and the cold fluid is then pumped back up to the solar collector.
The rate of the pump is intelligently managed by the controller. This reacts to the temperature of the fluid in the solar collectors and the temperature of the water at different positions in the storage tank to determine the optimal flow rate to maximise energy savings.
The ideal storage tank will have a twin coil heating system. The lower coil is heated from the solar collector, and the upper coil is heated by your conventional boiler. As hot waster rises this means that the water is heated as much as possible by the solar collector and then topped up as required, by your conventional boiler. This allows the maximum possible contribution from solar energy even during the shorter days of winter.
Those reading this with knowledge of boilers will recognise that combination boilers will not work very easily with this system. The problems can be overcome, but depending on the age of your boiler, it is often cheaper to completely replace your boiler. This is something that we’re happy to discuss with you, so we can talk about your individual circumstances.
HOW DO SOLAR THERMAL COLLECTORS WORK?
The technology behind solar thermal is completely different to the technology behind solar photovoltaics. Within a solar thermal collector there is a meandering copper pipework (1). This layout of piping maximises the time of the heating fluid within the collector whilst ensuring even pressure and therefore flow throughout the system.
The piping is covered by a high technology Sunselect absorber coating (2). This is a material specially designed to have extremely high surface area and absorb the high levels of sunlight to convert into heat. The direct contact of the still coating is the principle method of heat exchange into the copper piping.
Above the absorber is a pane of low iron content glass treated with an anti-reflective coating (3) which allows maximum transition of light into the collector and protection from the fiercest of hail storms. It also acts as a greenhouse keeping heat within the reflector.
Behind the copper pipework is a layer of fibreglass insulation (5), ensuring that the trapped heat cannot easily escape through the back of the panel.
The collector is held together by anodised aluminium (4). This is lightweight, weather and corrosion resistant ensuring it is perfect for roof mounting.
HOW MUCH WILL DOES SOLAR THERMAL COST AND HOW MUCH DO I SAVE?
The smallest system ideal for a home where two average or three water conscious people live starts at around £4,000 which includes the cost of all the material, the design, installation and testing of the system by fully accredited installers.
There is also a £400 grant available from the low carbon building programme.
There is a maximum sensible size for a solar thermal system based upon household hot water usage. This is something that we would establish with you during an initial consultation with systems available for all. A correctly sized solar thermal system is expected to save you between 50 – 70% of your annual hot water bill. If you're on mains gas hot water is likely to represent around one third of your total bill. Therefore a good system will save you 15% of your total gas bill.
AM I SUITABLE FOR SOLAR THERMAL?
Most properties that own their own roof space are suitable for solar thermal installation. As with all solar systems a roof facing south is ideal, but the loss in performance is significantly less that most people expect so there are very few properties that do not have enough roof space.
The easiest way to find out is to give us a ring or send us an email. There are quite a lot of questions to be asked, and we’ll also need to arrange a site visit to check everything from roof integrity to the type of storage tank that you currently own.
WHICH IS BETTER, SOLAR THERMAL OR SOLAR PHOTOVOLTAIC?
Solar thermal and solar photovoltaic technologies are both renewable, and EvoEnergy feel that both are worthy of investment. A question we are often asked is, which technology is correct for me?
Essentially, it all boils down to your lifestyle and why you want a renewable system. Ultimately, a very low carbon household will require both systems working in tandem, and going with a dual installation inevitably offers the lowest ancilliary costs as the systems can be installed in parallel. However many people have very real budgetary restraints and have to choose one system or the other.
A solar PV system works irrespective of whether you are in the house or when you are using your electricity because you are connected to the grid with any excess electricity being paid for by your distribution company. Therefore, the estimation of the electricity generated is independent of lifestyle and primarily dependent upon any seasonal variations in cloud cover.
The finances of a solar PV system are covered here.Solar thermal technology is most useful for homes where the occupants use hot water during the day and evening. In the summer months dawn is early enough to heat water for morning showers, but in the winter this will not be the case. If you lead a lifestyle where you are out of the house for large portions of the day and use your hot water predominantly before and after sunrise then you are unlikely to receive the maximum efficiency from a solar thermal system. However, the amount of heat generated and used is not easy to estimate in advance, or even calculate once the technology is installed. There is no easy to fit meter that shows the heat generated on your roof, and the proportion that you've used before it gradually drains away. There is also no way to measure the amount of the energy you'd have used without the technology, when you have limitless free hot water in the summer people often take longer showers, without guilt.
The bottom line is, that without any incentive at all solar thermal is not as good an investment as PV from apurely financial perspective, especially following DECC's announcement on the
feed-in tariffs. Environmentally it is a worthwhile technolgy, and the government is talking about a similar incentive from 2011, if that comes through then the tables might turn.