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Garage_Hermit

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Reply with quote  #11 
Hi, Jim,

Looked at your numbers for the glycol, and have to agree !

Also looked at your schematic for the panel angles: I think the difference comes from the fact that they are talking about the angle of "lift" on the panel - their angle is therefore the APEX of the triangle... whereas when I talk about inclining a panel, I mean, pulling the foot out from the wall...I which case I measure my angle at the ground level... (and I suspect I am far from alone on this !).

It's a long time since I did any geometry, but in a right-angle triangle (which is what we in effect have), these two angles are complementary - they add up to 90°...
So For your latitude of 56 North, adding on 15 degrees of tilt gives an angle of 71° at the ground, and 19° at the apex...
(this is for winter I'm talking about, when u need the most heat)

So for their solar panels, THEY show 10° (vs my 19°) - I guess it is an acceptable degree of error..., given the amount of discussion in any case that the subject generates !!

G_H

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maximoney1

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Reply with quote  #12 
Quote:
Originally Posted by Garage_Hermit
Hi, Jim,

Looked at your numbers for the glycol, and have to agree !

Also looked at your schematic for the panel angles: I think the difference comes from the fact that they are talking about the angle of "lift" on the panel - their angle is therefore the APEX of the triangle... whereas when I talk about inclining a panel, I mean, pulling the foot out from the wall...I which case I measure my angle at the ground level... (and I suspect I am far from alone on this !).

It's a long time since I did any geometry, but in a right-angle triangle (which is what we in effect have), these two angles are complementary - they add up to 90°...
So For your latitude of 56 North, adding on 15 degrees of tilt gives an angle of 71° at the ground, and 19° at the apex...
(this is for winter I'm talking about, when u need the most heat)

So for their solar panels, THEY show 10° (vs my 19°) - I guess it is an acceptable degree of error..., given the amount of discussion in any case that the subject generates !!

G_H


Hi G_H,

I think it comes down to what you are looking for out of solar PV versus skewing the angle for what you wish to get out of solar thermal. With PV, you are looking for the big summer boost to generat the best tariff returns, where as with solar thermal, you are skewing it towards trying to collect more heat gain in the winter.

It was the fact they were using 15deg, when the earth's tilt is 23.5deg. I just could'nt get my head around why the 15deg fudge factor would work better. At my latitude i estimate the june21 summer sun to be about 77deg high in the sky and dec21 winter about 28deg above the horizon. This would give panel angles of 13degrees(summer) and 62degrees(winter) respectively. 

Thanks for getting me thinking. [smile]

Regards

jim.


stmbtwle

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Reply with quote  #13 
Jim what kind of diverter valve are you using and where did you find them (Link would be nice). I can't find anything like you describe at a reasonable price. Thanks.
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Willie, Tampa Bay
maximoney1

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Reply with quote  #14 
Quote:
Originally Posted by stmbtwle
Jim what kind of diverter valve are you using and where did you find them (Link would be nice). I can't find anything like you describe at a reasonable price. Thanks.


Hi willie,

I think i used this one(honeywell) eventually, but had to drop my heat dump temp to 87deg. I had used another one, with a higher temp rating(think it was italian if i remember correctly, but cant find the info)

http://www.honeywelluk.com/products/Valves/Motorised-Valves/V4044C-Motorised-Diverter-Valve/

Edit... this is the first one i used....

http://www.renewable-energy-centres.co.uk/solar-3-port-diverter-valves.html
stmbtwle

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Reply with quote  #15 
Thanks that is what I was looking for. 240v won't work for me, but I suspect I can find a 120v version.
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Solar is like the wind. It may be free, but putting it to work isn't!
Willie, Tampa Bay
GreenBusinessWatch

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Posts: 1
Reply with quote  #16 

Hi Jim;

I had to read your post three or four times because I was so impressed! The way you describe your efforts as more of a labour of love (a "suck it and see" approach) as opposed to being a number-driven ROI exercise is so lovely to hear; all too often my path crosses with people who seem confused why their solar water heater is not doubling up as a 24 hour ATM!

You are absolutely right that, as your scrutiny on the numbers and on fine tuning efficiencies comes in to play, you will doubtless find some ways to optimize what you have and increase efficiencies even more.

There is a lot of data-backed FIT research out there, specifically pertaining to the UK, so it certainly pays to keep abreast of the variables. Legislative change (reduction in FIT rates specifically) seems to be a recurrent theme, but hopefully this is just a cycle. Below is the latest data-backed FIT information I have. I hope it helps.

https://greenbusinesswatch.co.uk/fit-data-analysis

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