Solar Thermal

Solar Thermal systems can generate up to 70% of a households annual hot water requirement and are an excellent source of renewable energy on their own or as a complement to solar PV.

Solstice Energy has it’s history in PV, but began installing solar thermal in 2009, and have worked with many different types and styles of collector including the more expensive, but aesthetically pleasing flat plate integrated panels (top row of photos), as well as less expensive but high efficiency evacuated tube collectors (bottom row).

Click for enlargements. All images are of Solstice Energy installations and © Solstice Energy

A short explanation

Solar thermal collectors are sized according to the size of the properties hot water cylinder, which in turn should be sized according to the number of occupants using the shower / bath etc. The cylinder will need a separate heat transfer coil for the thermal system, and a pump installed in the pipe circuit then pumps an antifreeze solution from the collector on the roof to the cylinder, where it heats the cooler water inside the cylinder, and then returns to the collector to be heated again and so on. This process is controlled from a display connected to a number of temperature sensors fitted on the cylinder and collector so that the pump is only operating when the conditions are bright enough to make it worthwhile.  

If you are interested in installing a solar thermal system please get in touch. We will need to know:

  • Is your existing boiler a conventional boiler or combi?
  • If conventional, is your existing hot water system gravity fed or pressurised?
  • Can you tell us the capacity in litres of the existing / proposed cylinder?
  • How many people use the hot water and what is your pattern of use (all in the morning or spread out)?
  • Do you have a preference for evacuated tubes or flat plate collectors?

Don’t worry if you don’t know all the answers, a photo or two of the existing heating system will often be enough, and we can arrange a site visit after sending you an estimate.

New - 'Renewable heat incentive'

The Department of Energy & Climate Change (DECC) have a consultation out now about the new 'feed in tariff' for solar thermal systems. Final details have not been announced, but it's likely to look like this:

  • A feed in tariff paid to the householder every year
  • The heat generated will not be measured (this cannot be done with thermal systems as it can with PV) - instead the tariff will be based upon a deemed amount of heat that a system will generate.
  • The amount likely to be paid is going to be between £200 pa and £400 pa. The figure has not yet been set.
  • If the householder takes up the new feed in payments any previous grant (usually the £400) will have to be repaid.
  • The payments cannot be claimed until April 2011 but from that date they can be claimed for all systems installed after 19 July 2009.
  • The annual payment will be made to the house owner for twenty years.

For more details see the consultation