Comments on: Solar Thermal Panels – Flat bed or Evacuated Tubes

By: Gregory Heins

Gregory Heins — Fri, 13 Nov 2009 19:19:08 +0000

Useful information there

By: radiant solar energy

radiant solar energy — Fri, 02 Oct 2009 18:11:59 +0000

radiant solar energy…

Solar Thermal Panels or Solar Water Heaters come in two main types Flat bed panels and evacuated tub [...]…

By: Geoff

Geoff — Fri, 24 Jul 2009 13:46:51 +0000

Hi Nick, the thing about renewable products is that you are buying 25 years of energy in one go. This is why people should buy a good quality product and have it professionaly installed.

By: Nick

Nick — Fri, 24 Jul 2009 13:09:48 +0000

Hi Geoff, had a look at the website, very useful , I’ve been looking at both flatplate and vacum tube and must admit that the tube option seemd the best way to go apart from price and reliability. The solaruk.net site along with teh solarkent site seem to indicate its almost down to personal preference – price seems about the same and witha 25 year warranty ! though must admit the tubes look to have the edge.

By: Geoff

Geoff — Fri, 24 Jul 2009 12:17:45 +0000

There are clearly some confusions over the complication and reliability of vacuum tube systems and flat plate. Like all products, some are built better than others. Many modern vacuum tube collectors have eliminated the glass to metal seal that has failed on many tubes. Some collectors, like the LaZer2 from SolarUK.com come with a 25 year warranty. With flat plate collectors, the seal between the glass or perspex cover can leak. once water gets into the panel, algae grows and reduced the output of the system.

By: Gary Burk

Gary Burk — Wed, 22 Jul 2009 16:00:08 +0000

I’m now building a home in the Colorado hills at 7500 feet altitude. It gets lots of sun, cold winters, lots of snow, and has frequent high wind (50mph) and occasional very high wind and large hail (building code spec is for 136mph wind). I’m concerned about the use of evacuated tube collectors in regard to both snow and wind driven hail. I’d like to start out with solar DHW assist and the home’s in-floor radiant heating is designed for low-temp (110F) solar heated water – but this must come later for budgetary reasons. Do you have application experience in this type of mountain environment?

Regards,
Gary Burk

By: solarkent

solarkent — Wed, 01 Jul 2009 10:25:09 +0000

I agree that Robert is right about the risks of Tubes against flat plate, also the fact that modern flat plate panles are not just a sheet of copper with a bit of black paint, much more sophisticated that that!

However to be fair to tubes, there are systems that avoid the cracking, in particular the failure where the copper meets the glass. I had a demo of solar tubes from solaruk (www.solaruk.com) where the evacuated tube is a totally seperate entity to the water circulation system, the tube fitting around the collector.

This particular layout doesn’t seem to be that common but possibly resolves the real problems that Robert has identified.

Certainly not a reason to go for tube wholesale, its just there are samples out there which might be appropriate.

By: robertkyriakides

robertkyriakides — Mon, 21 Jul 2008 11:25:51 +0000

I think that it is inaccurate to describe fevacuated tubes as more complicated technology; high quality modern flat plate panels have complicated technology and Genersys produce an evacuated flat plat.
Tubes are less relaible than panels becasue of tube failures. High quality panel failures are almost unknown, becasue the flat plates are designed to handle the heat stresses better.

It is highly inaccuarte to describe flat plates as being with a panel of black painted metal; these types only work in very hot countries. Most flat plates sold in the Uk are selectively coated, not painted.

Robert Kyriakides