Alternative Power sources - Rusty solar panels

Author

Rusty solar panels

Gazzamoller

2006-12-16, 3:25 am

I have made up a website about my not very happy experiences with solar
water heating. Have a look and let us have your comments. Is this a
widespread problem, or merely a localised phenomenom?
http://www.healthandlifestyle.co.nz/solarpanel/

Harbin Osteen

2006-12-16, 8:25 pm

Hi Gazzamoller:
Thanks for the info. I never knew that there was such a problem
with solor collectors.

--
SeeYaa

Harbin Osteen KG6URO

When American Citizens with dual citizenship pledges allegiance
to the flag, to which flag do they pledge allegiance too?

-
"Gazzamoller" <gary.moller@paradise.net.nz> wrote in message news:1166253145.554366.258950@73g2000cwn.googlegroups.com...
>I have made up a website about my not very happy experiences with solar
> water heating. Have a look and let us have your comments. Is this a
> widespread problem, or merely a localised phenomenom?
> http://www.healthandlifestyle.co.nz/solarpanel/
>

Loren Amelang

2006-12-16, 8:25 pm

On 15 Dec 2006 23:12:25 -0800, "Gazzamoller"
<gary.moller@paradise.net.nz> wrote:

>I have made up a website about my not very happy experiences with solar
>water heating. Have a look and let us have your comments. Is this a
>widespread problem, or merely a localised phenomenom?
>http://www.healthandlifestyle.co.nz/solarpanel/

I think "rusty" is the wrong term, but it did get my attention...

I've run between two and five 4x10 foot glazed collectors in northern
California for twenty years now. I haven't seen obvious corrosion of
either "black paint" or "black chrome" fins, made of either copper or
aluminum. But I'm twelve miles inland, and the air is not noticeably
salty here.

I have seen whitish mineral deposits on both the fins and the inside
of the glazing. From the locations and patterns it makes, it is pretty
obvious this is from condensation at night being burned off the next
day. I don't understand why condensation from the local air, which is
over a mile from a highway and eighteen air miles from the nearest
upwind village, wouldn't be very pure water. My personal suspicion is
that the deposits arise from the panels' synthetic foam insulation and
its aluminum foil surfacing. It is easy to see that the foam is slowly
disappearing.

The only serious problem I've had was due to running the system
"open-loop", with fresh domestic water in the panels. A couple of the
panels were 1.5 inch header "pool panels" and the rest were 0.75 inch
domestic panels. The larger headers happened to be plumbed downstream
of the smaller ones, and where the hot water slowed down at the
junction, it left huge volumes of mineral sediment that eventually
clogged several riser tubes enough that they failed to drain in
freezing weather and split.

I won't let anyone talk me out of running closed-loop with antifreeze
ever again! The cost and losses of a heat exchanger are insignificant
compared to just the hassle of maintaining a drain down valve. When
you add the efficiency losses due to mineral deposits inside the
collectors, and the losses of entire panels when they freeze and
burst, open-loop makes no sense at all.

I'm sure my remaining panels are less efficient than when they were
new and black, and their glass was perfectly clean. I even removed the
glazing once and attempted to clean and restore the glass and fins,
but I couldn't tell much difference in actual operation, and the
deposits were back almost immediately. I've decided they are a bit
like thin-film PV - you resign yourself to an initial output loss over
the first year or so, and buy enough to meet your needs after they
settle into their long-term output.

I'd be prouder of the panels if they looked clean and black instead of
mottled gray, but it is hard to argue with free heat, even if it is
less than the initial spec.

Loren

Gazzamoller

2006-12-17, 5:25 pm

Thanks for the comments Loren.
Few parts of NZ are not "coastal" as compared to continental regions
and it is assumed that there is much more salt in the atmosphere. The
corrosion, as you can see in some of the photos, after just a few years
is dramatic in some cases.
I would be interested in getting digital photos of NZ solar panels that
are proving themselves over time, as well as any that are not.

Ta!

Loren Amelang wrote:
> On 15 Dec 2006 23:12:25 -0800, "Gazzamoller"
> <gary.moller@paradise.net.nz> wrote:
>
>
> I think "rusty" is the wrong term, but it did get my attention...
>
> I've run between two and five 4x10 foot glazed collectors in northern
> California for twenty years now. I haven't seen obvious corrosion of
> either "black paint" or "black chrome" fins, made of either copper or
> aluminum. But I'm twelve miles inland, and the air is not noticeably
> salty here.
>
> I have seen whitish mineral deposits on both the fins and the inside
> of the glazing. From the locations and patterns it makes, it is pretty
> obvious this is from condensation at night being burned off the next
> day. I don't understand why condensation from the local air, which is
> over a mile from a highway and eighteen air miles from the nearest
> upwind village, wouldn't be very pure water. My personal suspicion is
> that the deposits arise from the panels' synthetic foam insulation and
> its aluminum foil surfacing. It is easy to see that the foam is slowly
> disappearing.
>
> The only serious problem I've had was due to running the system
> "open-loop", with fresh domestic water in the panels. A couple of the
> panels were 1.5 inch header "pool panels" and the rest were 0.75 inch
> domestic panels. The larger headers happened to be plumbed downstream
> of the smaller ones, and where the hot water slowed down at the
> junction, it left huge volumes of mineral sediment that eventually
> clogged several riser tubes enough that they failed to drain in
> freezing weather and split.
>
> I won't let anyone talk me out of running closed-loop with antifreeze
> ever again! The cost and losses of a heat exchanger are insignificant
> compared to just the hassle of maintaining a drain down valve. When
> you add the efficiency losses due to mineral deposits inside the
> collectors, and the losses of entire panels when they freeze and
> burst, open-loop makes no sense at all.
>
> I'm sure my remaining panels are less efficient than when they were
> new and black, and their glass was perfectly clean. I even removed the
> glazing once and attempted to clean and restore the glass and fins,
> but I couldn't tell much difference in actual operation, and the
> deposits were back almost immediately. I've decided they are a bit
> like thin-film PV - you resign yourself to an initial output loss over
> the first year or so, and buy enough to meet your needs after they
> settle into their long-term output.
>
> I'd be prouder of the panels if they looked clean and black instead of
> mottled gray, but it is hard to argue with free heat, even if it is
> less than the initial spec.
>
> Loren

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