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jamieF

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Reply with quote  #51 
collector.png I didn't take the time to add much for the flashing/fins and nothing is to scale but that's roughly what it should look like.   I'm just not sure if 1/2" airgap is going to cause issues

Garage_Hermit

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Reply with quote  #52 
Remarkable !

why not go for a thinner back, from my inexperienced viewpoint, those tubes *are* somewhat close to the glazing...

Updated
OR,

(if you cannot manage a thinner back), make a rabbet in it, so that one-half of the back is outside the stud ???

G_H

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(1)  "Heat goes from hot to cold, there is no directional bias"
(2) It's wrote, "voilà" unless talking musical instruments...
jamieF

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Reply with quote  #53 
I already have 2" polyiso so budget dictates it gets used.   I could cut a rabbit or something to make the stud slide inside the insulation but that would leave the coroplast outside of the stud and I'm hoping to use the coroplast and stud to add strength to the collector.    If I was doing this again I'd definitely do 2 8'x4' vs 1  16'x4' even thought he headers are way more expensive due to the reducing T's.  That would remove the need for the extra strength as there would be no joints in the foam.
jamieF

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Reply with quote  #54 
here's an option I just thought of.  Just add a spacer on top of the stud to move glazing up if need be.   It can't be foam as it needs to hold up to the sun but painted wood would be ok there. a strip of 3/4" plywood or something like that I'm sure I have kicking around.
collector2.png

jamieF

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Reply with quote  #55 
on a totally different note I took my test panel which is 2 sqft and set it up in the place the large 64 sqgt collector will be going.   I put 1 of the sensors from the collector harness inside of it.   It's really crappy build quality with dirty/messed up plexi on the front large air gaps 1/2" polystyrene in the back and no insulation in the sides.    It's currently 69C  with the outside air temp being 12C and it being really windy.    Gives me hope all of this may not be for nothing [wink]
Garage_Hermit

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Reply with quote  #56 
Great news about the test location !

Also brilliant idea, that glazing spacer !  (Even rubber hose might do the trick).

(I got to test my garage-door mockup today also, very nice & positive !)

G_H

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(1)  "Heat goes from hot to cold, there is no directional bias"
(2) It's wrote, "voilà" unless talking musical instruments...
jamieF

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Reply with quote  #57 
coroplast and steel stud fairy showed up at my house today so the project continues.  

I was a little dubious about the use of the stud track as it doesn't look the best in the pictures online.    It looked decent in person.   I slipped it onto the foam box and it looks quite good and will look excellent when painted up.  It also completely removed the movement from the joints in the foam box.  I'm very very happy with how that went together.  I'll finish the foam and post pictures tomorrow hopefully.



jamieF

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Reply with quote  #58 
or why wait until tomorrow... [IMG_20150228_221417] 
I'd be very surprised if the entire thing weight 40 lbs.   I can easily lift it weight wise but it's awkward enough that I want a second person to assist in me getting it off of the sawhorses so that I can sit the pipe grid on it and drill the necessary holes and run the wires in the back of it before putting the coroplast on it.      It's very rigid and shows no signs of flex when I lift it by one end.        I'm VERY happy with how it's turned out.    I'll use some construction glue to hold the insulation in for the places that it's a bit loose and I'll add a fair number more screws.  This was just enough to keep things rigid and let me move it around while I work on it.  I'll likely have to unscrew it to get the coroplast in but that can wait.

Construction of what exists here is really simple.  2" polyiso on the back.   I ripped one sheet in half so it's 4', 8' 4' to stagger the joints.   I used 5 pieces of  3/8" dowel about 5" long   in each joint to physically lock each piece together.  Just drilled a hole in the middle of the sheet added a drop of glue on each side,  inserted the wood then pushed the pieces back together.   It seemed to help.    I then wrapped the entire thing with the steel studs, the extra foam in the side required to fill the stud was cut from a chunk of 3" I have kicking around.  Each joint in the steel stud is overlapped by 8-10" and has 3 screws holding it all together. It all went together easy enough by myself.
jamieF

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Reply with quote  #59 
Here's a question for everyone.    I'm thinking the easiest way to mount this will be to just do a fixed mount rather then getting fancy and needing to figure out how to deal with moving water lines and so on 

I'm curious on what everyone recommends for the tilt angle.  I'm at roughly 49 degrees north.  the collector is 64 sqft.  My goal is 100% of my water heating so long as it's not overly cloudy.  That should be trivial to do but a few weeks of cloud followed by a few hours of sun then more cloud is pretty normal in the winter (Pacific northwest)  so I'm not expecting to actually get 100% water heating in the winter as I won't have a massive storage tank to carry through that long.

So I'm trying to buck the tilt angle.  I've seen latitude + 15 recommended a few times.  That would favour winter gains while hurting summer.  I'm assuming that my collector is large enough that I won't have any real concerns with summer gains?   is 64 (65 because my cutting won't be that accurate)  a perfectly reasonable goal to aim for? collector angle.png   



Garage_Hermit

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Reply with quote  #60 
Not wanting to put you off, Jamie, but I'd severely doubt that you would / will get the best of all worlds here [rolleyes]

Translation: a higher angle would be better for winter heating, and less good for summer...
But then, in summer you (presumably) don't require all that much heat...

The opposite (= a low angle) would work less well in Winter, and might be catastrophic in summer (such as CORE MELT-DOWN) [redface]

Looks like you have a choice between 60°C and 90°, or somewhere in between !
I wonder if it really matters ?  It is going to be a trade-off in any case (you will only have the exact good angle on two days of the year anyhow...).

Here is a tool you might find useful...
It is for an average UK location (which means presumably somewhere between 49° and 61° North):    http://www.solardesign.co.uk/sap/sap2009.htm

(BTW, just for the sake of it, SAP says to calculate the collector area on the basis of one-half of your summertime HW requirement.  So first off, what IS that requirement ?)

===============
open parentheses...
(I am at 48 N, and I have 100 square foot) (unglazed...)

My angle is going to be 90° vertical, period - I don't have any choice in the matter !

As for my summer HW requirement, it is very small - so small, in fact, that building a collector for DHW would scarcely make economic sense.  However, my collector is for winter-time heating -- and as much as I can grab !  I would MUCH prefer to have to dump "free solar" hot water to drain, rather than PAY the electric company a single CENT for heating my house [biggrin].  OK, I pay them a bit for heating my HW, you rarely get a free ride all the way !

===================
updated:
You said:

Quote:
I'm not expecting to actually get 100% water heating in the winter as I won't have a massive storage tank to carry through that long.


My comment is: why not - if you have the space, go for the biggest storage volume you can manage, and start loading it in August or whenever...

Multidrum storage is a good way to go, for both modularity and cost reasons ("you can always add a few more barrels in the future...").

G_H

__________________
(1)  "Heat goes from hot to cold, there is no directional bias"
(2) It's wrote, "voilà" unless talking musical instruments...
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