Comments on: Irish Firm Claims World’s Most Efficient Solar Heater

By: Dan

Dan — Wed, 09 Sep 2009 22:52:06 +0000

Quentin- any tips on where to find comparative details on the current
most efficient solar water heater systems??

By: Quentin Gargan

Quentin Gargan — Fri, 13 Feb 2009 21:47:57 +0000

Vacuum flask and tube systems work on daylight and are less affected by air temperature than flatplates are. This is because the heatloss through the glass in a flatplate is a lot greater – vacuum tubes have no air in them to convect the heat.

So production in winter will depend on the levels of daylight. In Ireland where I live and work, we get mostly grey days, and not much daylight. If you want to optimise output in a sunny climate during the winter, you will need to change the tilt angle to optimise absorbtion from a sun that is lower in the sky.

Anti-freeze is no problem. We use propylene glycol which as a standard solution is safe to -22 degrees. You can use a more concentrated mix. Its effect on performance is negligible.

External heat exchangers are inefficient. Our standard system here is to use a cylinder with a second coil – usually in the bottom of a larger cylinder. Q

By: Robin Green

Robin Green — Fri, 13 Feb 2009 15:47:23 +0000

How well do these systems work in really cold climates like Canada, where even in Toronto it can drop to -20C in February? I think many of the solar water heaters hear use antifreeze and a heat exchanger, which makes them more costly to install and less efficient to operate. I know that’s how the solar laundromat near my house heats their water, at least in winter.

By: Quentin Gargan

Quentin Gargan — Mon, 09 Feb 2009 00:32:42 +0000

These panels are the same as all other Chinese vacuum flask systems. The reason they benefit over flatplate panels is because they passively track the sun. In fact, they work better in the morning and evening than they do during the daytime. This is known as “incidence angle modifier” and you can find this feature on any Chinese Panel test. For example, see test results here, where the panel is 40% more effective with the sun at an angle of 55 degrees http://www.solarenergy.ch/factsheets/scf885en.pdf

Nice spin, but nothing new here I’m afraid. There are two thousand factories in China making this sort of panel (literally!). They work well…

By: jeez

jeez — Sun, 08 Feb 2009 21:57:43 +0000

Cool, I want one. But I need a house first… unless I use my small patio?

By: Irish Firm Claims World’s Most Efficient Solar Heater | Alternative Energy News

Sun, 08 Feb 2009 03:07:27 +0000

[...] An Irish company, Surface Power, has launched what could be the most efficient solar hot water panel ever produced. The company says it plans to distribute is product internationally. The new solar panel was independently certified by TUV Rhineland. Their tests verified that when compared to other solar panels, Surface Power’s solar panel was in one case as much as 131% more efficient in the morning and evening, and 76% more efficient at midday. (more…) [...]

By: thomas

thomas — Sat, 07 Feb 2009 10:35:09 +0000

“Surface Power’s solar panel was in one case as much as 131% more efficient in the morning and evening, and 76% more efficient at midday.”

Most likely compared against flat panel solar heaters. It would be interesting to see details of the comparison against evacuated tube solar heaters, which China has numerous manufacturers with many years of experience manufacturing on a massive scale. The biggest ones are using cutting edge automated manufacturing technology.