Building VS Buying Solar Collector.

[Drums]

I was wondering if anyone knows of good plans for these?
I see them all over the place and don't mind buying them but I'm afraid
I will waste my money on a useless set of plans. Obviously if someone knows
where
there are free plans that would be the best.

Also im interested in input regarding building your own or buying them.

Regards.

Tom

 

[SQLit]

I was wondering if anyone knows of good plans for these?
I see them all over the place and don't mind buying them but I'm afraid
I will waste my money on a useless set of plans. Obviously if someone knows
where
there are free plans that would be the best.

Also im interested in input regarding building your own or buying them.

Regards.

Tom

What type of solar panels do you want?

I have built hot water collectors and I have paid for them. The store bought
have always out done my home made ones.

As for building PV, I can not speak on that subject.

 

[Anthony Matonak]

I was wondering if anyone knows of good plans for these?
I see them all over the place and don't mind buying them but I'm afraid
I will waste my money on a useless set of plans. Obviously if someone knows
where
there are free plans that would be the best.

Also im interested in input regarding building your own or buying them.

....

Solar air heaters are fairly simple to build out of common materials
so building them vs. buying seems quite reasonable. Plans are available
for free and there are a lot of examples on the net showing people
who have built their own.

Solar water heaters are a bit harder, though still possible. If
you're not handy with tools and plumbing then you might do better
just buying them.

Solar PV (electric) cells are nearly impossible for a homeowner to
make themselves. You can buy a bunch of cells and assemble them into
a panel yourself but it'll cost almost as much as buying a panel and
it's unlikely you'll match their quality.

Anthony

 

[Drums]

Sorry I meant solar hot water system. Will be used for hot water and heat.
I plan on having 4 or 5 panels and 1000 gallon storage.

 

[SQLit]

Sorry I meant solar hot water system. Will be used for hot water and heat.
I plan on having 4 or 5 panels and 1000 gallon storage.

washing and heat in the same tank, not a good plan my friend. Most systems I
have seen installed keep heating and washing seperate. Washing water is
potable/drinking and heating water is generally mixed with chemicals to
prevent the water from eating away at the piping system.

I had one 4x10 collector facing southwestish. Mine was mounted so it had the
roof pitch. Close but not optimal. I had a Lockinvar 80 gallon water
heater. Summer time, the water was "toasty" almost dangerous. Winter time
I really needed another panel. The electric back up ran more than I liked.
My Grunfos pump was good for about 10 gallons an minute and 20 feet of head.
I live in Phoenix, and there was only 2 adults in the home.

You can heat a little water a lot, or a lot of water a little. Not much in
between.

You do not mention what latitude your at so just guessing the 5 panels and
1000 gallons aint gonna happen. Unless you want to raise the water a degree
or two.



---------snipped==================

 

[Drums]

The system I plan on building will be a closed one. The heat exchanger will
help boost incoming water temp
and the stored water will be used for baseboard heat and to boost incoming
water witch is 55F, not terribly cold. You're correct In that I would need
allot more panels. I have 4 200 gallon tanks, so I will likely start with 4
panels with a 200 gallon and see how that works.
FYI this system will be PC controlled only because I have the software and
hardware. I will be using
Labview to do this. I know there will be some loss with the heat exchanger
but I have decided I want a closed system.
I live in the northeast. The object is invest a minimal amount so that's
why I was trying to see if it's cheaper to build the panels
of just buy them. I have almost all the valves, pumps, thermocouples and
other parts.
Point taken on raising a little water lot, and lot of water a little. I'm
assuming with enough panels
however I could raise a lot of water to a pretty high temp if insulated well
enough.
That is the main reason I am after a cheap way to build them. I have room
for 8 of them easy if not more.
To buy 5 new panels would cost over 2k.

 

[[email protected]]

Mike Pelletier has an interesting idea:

What about a single polycarbonate panel over black painted aluminum roofing
that is tilted so the high end is 6" further to the south away from the
house wall than the bottom. Trickle water down the backside (out of the sun)
of the roofing. Protect the house wall with roofing paper and/or polyethylene
and seal the panel so the polycarbonate doesn't get moisture.

IIRC, ABC sells thin dark green galvalume barn roofing for 30 cents/ft^2.

If it's collecting hot water and the house also needs heat, it could be
more efficient with some house air flowing between absorber and glazing:
if 225 Btu/h-ft^2 of sun enters that space and it's 20 F outdoors with 120 F
water, R1 glazing would lose 100 Btu/h, so we might collect 125 Btu/h. If
2 cfm of house air flows into the bottom at 70 F and out at 120 F and the
average temp near the glazing is 95, we might only lose (95-20)/1ft^2/R1
= 75, collecting 150 Btu/h, or more, if the 70 F air stays near the glazing
and the 120 F air stays near the absorber.

Nick

 

[SJC]

Mike Pelletier has an interesting idea:


IIRC, ABC sells thin dark green galvalume barn roofing for 30 cents/ft^2.

If it's collecting hot water and the house also needs heat, it could be
more efficient with some house air flowing between absorber and glazing:
if 225 Btu/h-ft^2 of sun enters that space and it's 20 F outdoors with 120 F
water, R1 glazing would lose 100 Btu/h, so we might collect 125 Btu/h. If
2 cfm of house air flows into the bottom at 70 F and out at 120 F and the
average temp near the glazing is 95, we might only lose (95-20)/1ft^2/R1
= 75, collecting 150 Btu/h, or more, if the 70 F air stays near the glazing
and the 120 F air stays near the absorber.

Nick

I like the idea of air collectors. I have a patio cover that could take air
from the house under the corrugated material and return it on the top facing
the sun. Top the material with some multiwall polycarbonate and you have
a pretty cheap solar collector for maybe $100 per 4' x 8' section.

 

[SQLit]

The system I plan on building will be a closed one. The heat exchanger will
help boost incoming water temp
and the stored water will be used for baseboard heat and to boost incoming
water witch is 55F, not terribly cold. You're correct In that I would need
allot more panels. I have 4 200 gallon tanks, so I will likely start with 4
panels with a 200 gallon and see how that works.
FYI this system will be PC controlled only because I have the software and
hardware. I will be using
Labview to do this. I know there will be some loss with the heat exchanger
but I have decided I want a closed system.
I live in the northeast. The object is invest a minimal amount so that's
why I was trying to see if it's cheaper to build the panels
of just buy them. I have almost all the valves, pumps, thermocouples and
other parts.
Point taken on raising a little water lot, and lot of water a little. I'm
assuming with enough panels
however I could raise a lot of water to a pretty high temp if insulated well
enough.
That is the main reason I am after a cheap way to build them. I have room
for 8 of them easy if not more.
To buy 5 new panels would cost over 2k.

--------snipped again========================

Closed? Please re-think that idea. Your water comes from an open system.
When ever you use water your injecting fresh oxygenated water. OK for
potable.

55 F is cold. I work on a chilled water system that has warmer water coming
back than that.

You need to bring that water temp up to ~100F for bathing, and 140F for
heating.

Your planning on tracking the solar collectors. Wow what a project. I guess
your planning on parabolic collectors. I have never seen water filled flat
plates tracked. Gonna need some gearing on that mechanism.

Are you in Arizona? If you are contact TEP in Tucson or APS in Tempe and
ask for a tour of their solar facilities. I have never seen the one in
Tucson, but the one in Tempe is staggering. These guys will try almost
anything to see if it will work.

Good luck an post your progress.

 

[Drums]

I am planning on tracking the collectors? Don't know where you got that
idea although I could do it
if I wanted to spend the time.
I don't think you understand the nature of this project. This is strictly
for supplemental.
I want a closed system. I have researched it and thought about it.
I already have the heat exchangers. I don't need 140F. 110f would help
reduce the heating load
on the gas furnace. I plan to run 4 collectors to start with.

 

[Drums]

This gives me a though. I could use 2 collectors for hot water and 2 for
air for heating and keep the systems
seperate.

 

[SJC]

This gives me a though. I could use 2 collectors for hot water and 2 for
air for heating and keep the systems
seperate.

Or, just combine them. Run some tubes with clamps along the corrugated.
It depends on thermal resistance and insulation, but it might work.

 

[Drums]

Thanks Gary. Very usefull info.

Hi,
Lots of plans here:
http://www.builditsolar.com/Projects/SpaceHeating/Space_Heating.htm
and here:
http://www.builditsolar.com/Projects/WaterHeating/water_heating.htm

Another alternative is to build most of the collector, but buy the absorber plates.
I am doing this for my solar heating project -- described here:

http://www.builditsolar.com/Experimental/InWorkshop/SolarShed/solarshed.htm

Sunray makes some $4.50 per sqft absorber plates.

If you can use air collectors instead of water collectors, then building
collectors gets even simplier. If well integrated with the structure, they
can cost as little as $2 per sqft (vs $20 and up for commercial panels).


--


Gary

www.BuildItSolar.com
[email protected]
"Build It Yourself" Solar Projects










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[Drums]

I have looked into those. It would take years for a payback.
That's the whole Idea with building my own.
I have plenty of room. So what If I need 6 flat plates.
That = the cost of 2 evacuated units.

 

[Drums]

Im sure they won't but Im not looking to get much out of them in the dead of
winter.
I expect thay will help reduce my hot water heating costs and provide some
heat assistance
in the milder months. If the outside temp is say 30 and the water temp
reaches 90F on a sunny day
that adding heat to the house is it not? Remeber that this is not going to
be a primary source.
Im only looking to reduce my heating bill and hot water bill. 6 Flat plates
should give me
at least 200 gallons of hot or warm water storage. If insulated well that
should reduce the heating load considerably
on a sunny day no? I may well end up being that even building my own won't
give me much of a payback
but I don't think would be the case running 6 collectors.

 

[Drums]

What if you Insulated the homeade flate plate very well?
Yea they would be heavy but I can get large Double pane glass doors for
almost nothing from salvage.
They allready have an aluminum frame.

 

[Anthony Matonak]

Buy_Sell wrote:
....

But if you are trying to solar heat water as efficiently as possible in
cold climates, you are going to need all the help that you can get.
These evacuated tube solar collectors are so efficient that they are
producing heat even on the overcast days. Its the high insulation
factor of the thermos bottle style collector that is achieving this. I
cannot repeat this enough, a vacuum will give you the highest
insulation factor available.

....

It's not the highest insulation that the fellow is really looking for,
it the best bang for the buck in heating. How hot it gets is the balance
point between energy going in via sunlight and going out via conduction,
radiation and convection. Better insulation means that there is less
energy going out but you could go the other way and use bigger panels,
reflectors or both.

Anthony

 

[wmbjk]

The biggest problem I have metally encountered on this
is any kind of concentrator takes a solar tracker and
they get complex and cost money and moving space.

Perhaps if you actually built something, or even listened to those who
have, then you'd find it's not as difficult as you've "metally
encountered".

Wayne

 

[Drums]

There is no doubt you can't beat that however I don't need the heat the most
on any day because I have an LP
furnace. The system I am proposing is strictly supplemental. The idea is to
reduce the average draw on the furnace and hot water heater.
If I had the spare cash I would spring for the vac tube unit.