Evacuated Tube Solar Panels

Evacuated Tube Solar Panels

Evacuated tube solar panels installed on a roof in Wicklow overlooking a lake

Evacuated Tube Solar Panels on a roof in Wicklow

Evacuated tube solar panels are one of the the two main types of solar collector- the other being flat plates.  It is a commonly held view that evacuated tubes, or vacuum tubes as they are also known,  are more efficient than flat plate panels - this is correct..  kind of.

The thing is that the source of energy for all solar panels is determined by the surface area they present to the sun.  The more surface area solar panels have the more solar energy they can collect.   If you compare evacuated tubes to flat plates on a like for like surface area basis e.g. 1 m2 of evacuated tubes compared to 1 m2 of flat plate solar panels - decent evacuated tube collectors will win out in terms of energy production.  This is because they are more efficient at converting 1 m2 worth of solar energy.



Tubes and Flat Plate Solar Panels

However the reality is that evacuated tube systems are typically much smaller than flat plates in surface area so the like for like comparison above doesn't come into it in the real world.  What actually happens is solar water heating systems are sized to produce a certain amount of energy over a year - this is usually about 60% of the average energy required to heat your water for a year.  You can size a flat plate system to give you this amount of energy same as an evacuated tube system.  The point really is don't make a decision on buying evacuated tubes because they are more efficient because this does not mean you will get any more energy for your money - there are other good reasons to buy evacuated tube solar panels and they're listed below.  you can see the price of evacuated tube solar panels here.

  • They are smaller -  Good evacuated tube solar panels - solar panels -  vacuum tubelike Kingspan tubes, generally have a smaller footprint on a roof so can fit in smaller spaces if needs be.  It also frees up more space on a south facing roof for solar PV for generating electricity.
  • They are modular - Some evacuated tube solar panels like the Varisol panel can be built tube by tube so if you want to expand a little in the future (when the kids turn into teenagers..)  you can add a few tubes to get more energy.
  • They have a better warranty - Kingspan tubes come with a 20 year warranty, flat plate solar panels come with 10 year warranties.
  • They produce more energy in Winter - Evacuated tubes are much more insulated then flat plates and so hold on to more solar energy in colder, windier conditions.  This makes them more productive in Winter.
  • They are better beside the sea - Flat Plates have been known to suffer from salt corrosion on their absorbers when installed close to the sea.  We recommend evacuated tubes in this scenario as the abosrbers are fully sealed.

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