Once you have established that your site is suitable for solar thermal, it is then important to decide which type of collector you would like installed. Enviko offer two types of collectors used for solar water heating applications; flat plate collectors and evacuated tube collectors.
Flat plate collectors are cheaper, more rigid and are historically the predominant type used in domestic systems worldwide. They are constructed of a metal frame, usually aluminium and coated in special materials and fitted into an insulated box. Tubes run internally between reflector plates carrying a water, glycol mix and heat is conducted from the surface of the collector into the water.
Their efficiency in converting energy in the sun to useful heat in the water is less than that of evacuated tube at certain temperatures, however, they still perform well. Flat-plate collectors are ideal when there is limited roof space and provide a more aesthetically pleasing design. They are also ideal for swimming pool applications as they provide a constant supply of heat to raise the pool temperature.
The more modern evacuated-tube collectors are slightly more expensive due to the superior quality in manufacturing. The collector is made up of transparent glass tubes which contain a copper heat pipe and an absorbent coating. The coating converts the light into heat which is transferred to the pipe. Within the glass tube a vacuum is created by evacuating the air providing almost perfect insulation, eliminating conductive and convective heat loss, helping to achieve high temperatures and resulting in a higher efficiency. This leads to improved performances in colder conditions, ideal for the conditions we experience in the UK.
The efficiency is also increased due to the cylindrical shape of the evacuated tube. The suns energy is harnessed from multiple angles due to the tubular design, whereas, flat plate collectors will only reach their peak output at the mid-point of the day when the sun is perpendicular to the surface. Evacuated tubes, therefore, achieve much higher efficiency’s in the morning and afternoon.
During the summer months both types will contribute similar savings, however the difference in cost will be noticed during the winter period when the superior performance and heat gains from evacuated tubes will be found over that of the flat plate collector.
Solar collectors are mounted on roof locations that are orientated to face the sun. There are various mounting options available. A typical pitched roof can have a collector attached to the roof without any alteration to the surface covering or any need to penetrate the surface. Flat roofs can have an A frame built to elevate the collector the appropriate angle.
The optimum angle for mounting a collector is 30-45° off the horizontal. The closer the mounting angle is to this optimal value, the more efficient the collector will be but slight variations do not have a very significant effect.
Most pitched roofs have angles of 30-50°, the actual angle (pitch) is generally determined by site exposure and local climate.
Our collectors are generally mounted on top of the roof as can be seen in the picture. The other system components are then simply linked from the collectors to the hot water cylinder via the pump station and a control unit via the pipework.
For more information on this or any other Enviko services or products please call Enviko on (England & Wales) +44 (0)20 8816 7631 or (Scotland) +44 (0)131 335 0032 or by email.
Solar PV - We are experienced specialists in solar PV. In recent years solar has become an increasingly popular method of generating renewable electricity.
We can reduce your carbon footprint and help you to demonstrate your green credentials.
Wind - Enviko provides turnkey engineering solutions for wind turbine sites. With our wide knowledge and experience, we can guide you along the most effective and affordable path to delivering your wind project. Enviko’s expertise resides in grid connection, civils and foundation design, wind turbine erection, installation and commissioning and on-going Operation and Maintenance Services both Preventative/On-Going and Unscheduled.
Renewable heating - We can provide commercial bodies with a range of renewable heating solutions, including biomass, heat pumps and solar thermal.
We find the best solution to match your budget and energy demands.
England & Wales:
+44 (0)20 8611 2741