Evacuated tube solar panels are the priciest but most effective kind of solar thermal panels. Their conversion rate is 90%, which allows them to generate more heat compared with other solar thermal systems.
How do evacuated tubes work?
An evacuated tube features a small glass tube which is kept in a larger tube. The air is pumped through the space between the inner tube and the outside tube, which makes a vacuum thermal insulation layer. This layer keeps heat loss from the solar collector to a minimum.
The inner glass tube is coated using a selective light absorber made from lightweight aluminium nitrate or sometimes titanium nitrate oxide. It can help increase the absorption of the sun’s rays. An absorber plate runs through the inner glass tube. Usually, that is made from copper, and it absorbs heat then moves it to a heat transfer liquid.
When the transfer liquid gets hot, it evaporates then turns to steam, which rises to the top of the panel before the heat is transferred through a heat exchanger to another liquid. The cycle then starts once more after the transfer fluid condenses and falls into the evacuated tube.
Considering the fact that evacuated tube solar panels are the priciest, you may be not sure if they are best for you. Check out the pros and cons to help you select.
Evacuated tube panels produce much more heat in comparison with other systems
Since the panels are 90% effective, you can generate a lot more heat using evacuated tube panels compared to flat plate collectors. While you may pay more for installation, you can heat a lot more water, which will save you money in the long term.
You could save £60 per year on gas expenses
When you have a gas heating system, you can see a saving of £60 every year on your home heating expenses. Solar hot water is free to generate, so for that reason you will see the difference in your pocket within couple of months.
Save 270kg CO2 in contrast to gas
Solar thermal panels are unquestionably a better way to cut your own CO2 impact. They generate heat from sunlight, a renewable resource, so you can do your small part to reduce the use of fossil fuels and help reverse global warming.
Get hot water all through the year
Regardless of Britain’s winters, you are able to get some great free warm water out of your solar panels all the year.
Get £349 every year from the Renewable Heat Incentive (RHI)
If you get your evacuated tube solar panels installed by an MCS-registered professional, you might be able to make money for producing heat with your solar hot water system with the government’s Renewable Heat Incentive (RHI). A 2m2 system, which is generally enough for a two-person home, may enable you to get £200 each year from the RHI, while a 4m2 could get you £345.
You might need a backup heater
Through the winter weather, you may not manage to get your hot water to the ideal temperature. What this means is that you’ll need a backup heater, which of course will cost you money on electricity or gas.
Thermal solar panels are not compatible with combi boilers
Combi boilers provide instant hot water and they don’t have a separate hot water tank. They are not compatible with solar hot water systems, so if you want solar thermal panels you will have to replace your boiler. This could drive the cost up by at least £1000.