On 2/14/2012 2:23 PM, Jim Wilkins wrote:
>> On 2/14/2012 1:32 PM, Jim Wilkins wrote:
>>>
>>> Do you know how it compares as collector glazing to Suntuf polycarbonate
>>> panels from Lowe's or Home Depot?
>>
>> The Lowes corrugated definitely does *not* have a UV shield.
> It's on only the label side of Suntuf, both on Suntuf UV2:
> http://www.palramamericas.com/docs/upload/F409_Suntuf_Install-1-21-11.pdf
> See Panel Orientation on page 5.
I hadn't heard of the SunTuf UV2 before.
My rough understanding is that polycarbonate deteriorates under UV,
acrylic (plexiglass) does not.
http://en.wikipedia.org/wiki/Polycarbonate
UV resistance: fair
What an amazing thing Wikipedia is... that is hard to find info. I had
only heard it previously, anecdotaly.
It seems the original idea behind the UV coating was to protect the
material itself, not what is behind it. How the Lowes' polycarbonate
does this, I do not know, but it does.
Thanks for the link. I didn't know they suggest cutting with the
blade reversed...
Jeff
> jsw
On 2/14/2012 12:48 PM, Morris Dovey wrote:
> On 2/14/12 7:15 AM, j wrote:
>> Anyone doing solar thermal here? Perhaps Morris?
> I'm taking a break from solar thermal to see if I can incorporate a LENR
> heat source into one of my solar designs. See bottom of
> http://www.iedu.com/Solar/Electricity/ and
> http://www.iedu.com/Solar/Electricity/Fusion.html
Glad to see you working on something new and bold! Anything new on the
fluidyne?
>> I've just reworked my Kreamer style pass through collector. 25' * 8' of
>> south facing collector (+ another 16" on top). Black felt for the pass
>> through, SunTuf glazing with a layer of mylar underneath for double
>> insulation. I'm drawing the air out and ducting it into a collector box
>> and then distributing that into the heating vents. I'm getting about
>> ~16,000 BTUs/hr (20F delta at ~650 CFM) when the sun shines, but I
>> suspect some unfound leaks.
> Good. Seal your leaks and work to minimize the delta-T. A large delta-T
> means high (re)radiation losses and airflow resistance.
It's forced air. I have a collection box 25' back from the collector
sucking air back (12" flex duct). A smaller delta-T would need a bigger
fan. When the sun drops the delta-T moves down to 5F or less.
I suspect a leak because when I close the inlet to the collector I
still have an outlet flow. I may go around with a can of spray foam
insulation. Or wait for a still day and test it with some incense sticks.
>> I've got the collector divided in half so I can throttle down half when
>> it falls in shade. The collector sits slightly to the west of due south
>> and solar gain starts about 3 hours after sun up.
>>
>> If anyone is working on something similar, I'll post up some pics and
>> data. There is a lot unknown to me at this point.
> Welcome to the club. Pix and data would be welcome!
I'll post up something tomorrow. I have too much on the plate today!
>>
>> One of the other projects has been the solar cabana, which has the roof
>> (formed of 3/4" 10' irrigation PVC, ie thin wall) glazed in corrugated
>> polycarbonate with vinyl under. The sides are all single wall vinyl (~8
>> * 10' footprint). That heats up nicely, well into the 80's on a blustery
>> 40F day, but of course loses heat rapidly at sun down. But during the
>> day a delight to pour a glass of scotch and image myself in the tropics.
> You might be very pleasantly surprised by the performance of twinwall
> polycarbonate glazing. If you orient the channels vertically, it may
> even extend the collection day. :-)
I haven't found a local source for twinwall. Does it have the UV shield?
I ran the Lowes version of SunTuf which is minus a UV shield and the
felt turned gray after a year or so. My understanding is that mylar can
deteriorate under UV. I moved the Lowes corrugated polycarbonate over to
the solar cabana and put in some 4 mil and 8 mil vinyl under. I suppose
I'll see what the sun does to that eventually... So, I've got 1 mil
mylar, 2 mil mylar, 4 mil vinyl and 8 mil vinyl in the test bed. If
nothing else, I'll see what fails! I think the vinyl is UV transparent,
but I don't really know.
Cheers,
Jeff
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>>>
>>> Do you know how it compares as collector glazing to Suntuf polycarbonate
>>> panels from Lowe's or Home Depot?
>>
>> The Lowes corrugated definitely does *not* have a UV shield.
> It's on only the label side of Suntuf, both on Suntuf UV2:
> http://www.palramamericas.com/docs/upload/F409_Suntuf_Install-1-21-11.pdf
> See Panel Orientation on page 5.