[Strawbale] Chinese-made evacuated tube collectors and boilers vs. hot water heaters

[Shody Ryon]

> Furthermore, there are some that are surprisingly
> affordable--such as
> the Chinese-made evacuated tube collectors that have
> been as low as
> $800 or so for a reasonably-sized unit. It is not
> difficult to create
> a setup that has an incomparable lifecycle cost
> where
> there is
> sufficient sunlight year-round.

Hi,
evacuated tube collectors are recommended for points
tropical and were snow is not likely to cover the
collector, blocking the sun. they are too delicate to
scrap snow off of because they have glass tubes like
old style florescent light bulbs sticking out of them.
I think it might be dangerous to walk around on the
roof covered in snow trying to clean snow off light
bulbs anyhow. 

Flat panel collectors are recommended for the North
West US and temperatures around 70 degrees F or less
because they are more effcient at heating water at
those temps. the colder it gets, the better flat panel
work than evac tubes, I think. Perhaps the colder and
hotter it is, Flat panel work best, mild temps evac
tubes work better. Flat panel do not heat water as hot
as evac tube collectors, so if you need 160 degrees
evac tubes might be the best choice. Evac tubes are
better at collecting heat in between about 20 degrees
and 90 degrees on cloudy days, if I am reading the
graph correctly. Please do not use the figures I give
here, I am giving them to show the types of things to
consider, not because I am good at interperting black
and white graphs that show 3 types of collectors on
sunny days and cloudy days using solid and dashed
lines. This has got to be the worst graph I have seen
in at least 2 months!
Flat panel are the most common type of collector.
If the rubber seals in the glass tubes fail on evac
tube collectors, they probably will work less well
than Flat Panel, which does not have rubber seals, I
think.
Shody


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