Solar Collector

[dexxy]

Hi Everyone!

I had a friend call me up last week (they do commercial stuff) and told me he had a solar panel for me if I wanted it.  I'd have to go get it off of a roof and get it out of there.  So I called in a favour with someone who has a boom truck and went and got it.  It's at home now and it's in pretty good shape.  It's about 10 feet by 6 feet; there are no markings on it so I don't know where to start looking to see what it's capacity is or what to do with it.  I also got the hot water tank with heat exchanger coil with it.   Here's a picture, and if you have any idea please let me know.

Thanks, Greg

[Gordy]

LUCKY BUGGER ;-)

Gordy

[Titantornado]

I'll second that!!!

[rmiller021]

Lucky indeed.

Those are evacuated tube solar collectors.

Here is one company that sells them.

http://www.solarhotwater.siliconsolar.com/evacuated-solar-tubes-20.php

The panels alone probably originally cost over $800.

This would be a great system to augment your existing hot water heater. Possibly with conservation replace your current system.

Lucky Lucky man

rob

[dexxy]

Great! So I have something here that would be pretty efficient?  When the weather gets better I'll have a closer look at the hot water tank.  It has a heat exchanger in it but I don't know if it leaks or not.  Also have to get a controller and a pump I think.

Thanks for the help, Greg

[ptitchard]

I wish I had some friends like yours.

I installed a home made system about five years ago which uses convection therefore cutting out any requirement for pumps and controllers. However my collector is only a old very large radiator painted black in a sealed box. With your high efficency one you may need a presurised system with all the bells and whistles to prevent it boiling the water.

Good luck with the installation these systems are sure to bring down your energy costs more per pound spent then PV's or wind, and in your case especially as probably 70% of the system was free.

[coldspot]

Good to be you !!!

What I'd like to know,

is what was put back in?

If they pulled a "evacuated tube solar collector"

As I understand it thats the state of art in this field, so what would be the replacement for this?

[hydrosun]

Lucky indeed. I've installed a few of these systems and wish I had some at my house. I've got the older less efficient flat plate solar water heaters.

You can still use thermosyphoning to move the heat from the top of the panel to the hot water tank if you can put the top of the  panel lower than the bottom of the tank.  You'd need an open resevoir above the hot water tank to allow for expansion of the fluid in the heat exchanger.  If the tank is lower than the solar panel you'll need a pump. The simplest system uses an El Sid 12 volt pump connected to a 10 - 20 watt solar panel to run when there is enough sun to make electricity to move the pump.  And an expansion tank.

 The only reason I can think for someone to take this system  off is laziness. It may have had to be taken off for reroofing and they didn't want to have to put it back on.  Or the controller  or some other small part failed and they didn't want the "hassle" of fixing it.

Chris

[wdyasq]

"The only reason I can think for someone to take this system  off is laziness"

Or, ... having been there ... an inept 'tech' was sent who spent a bunch of time (money) and still didn't have an operating system. As the tax credit had been issued at time of purchase it just didn't make sense to request another  ... possibly as ignorant or stupid ... repairman. After all.. the guy with enough foresight to use solar transfered, died, or retired.

Businesses have requirements hobbyists don't. They HAVE to make a profit. Any costs are passed to the consumer. Also, accountants like easy numbers. If there is a cost of X per M units of heat and they can get a hard cost on it, that is good. Few enjoy telling a room full of superiors "If we have a sunny winter our costs will be approximately X dollars but if it is like (year number here) it could be 2X."

I can think of 4 or 5 other 'reasons' one might choose to 'get that piece of junk' off the roof. We aren't privileged to that information. It very well can be legitimate. It might very well be far off base, in your or my opinion. It could be as simple as the 'boss' stating, "I want the system back up in X hours or, you will no longer be employed here." Now, with a family to support, do you do the right thing for the environment or keep your job ...

Just a few reasons some get 'lucky' in the RE hobby some time.

Ron

[dexxy]

The reason is that the building is being torn down to make way for a new condo/retirement development.  Because the land the buildings sit on is parkland, in order to lease the land for 99 years they had to tear the buildings down which is a crying shame because they are fantastic buildings in really good shape.  You'd just cry if you saw the shops! but that's the gov't I guess...

But I can guarantee that I'll make a good home for them   I'll be sure to post some pics of my install as soon as I get going on it.  (It's finally in the 60's today, (it was -10F a few days ago when I took the panel off the building).

Greg

[betwixt]

Woooooooaaaaaaahhhhhhhh!

Go no further.

Either the photograph is upside down or you have the panel the wrong way up. If you try to use it as shown it will generate very little heat, possibly none at all. The evacuated tubes house a sealed pipe which contains liquid. The heat evaporates the liquid and in its gaseous state it rises to the top of the tube which is inside the manifold box (where the inlet and outlet pipes connect). On hitting the water being pumped through the manifold, the gas condenses, giving up its heat and drops down the pipe again ready to be recycled.

If you put the manifold at the bottom as shown in the picture, it will be at the cold end of the tubes and do very little.

I use two similar tube arrays, one of 20 tubes for domestic hot water and one of 180 tubes for heating a swimming pool. If mounted optimally and the right way up, you should get something in the region of 500W equivalent electical heating power per square metre (yard). Be very careful not to expose the tubes to direct sunlight without water flowing in the manifold. Uncooled they can reach in excess of 200C !!!

Brian.

[dexxy]

Good Eyes Brian  The panel is upside-down.  That's just how I leaned it against the wall when I brought it home.  I think that the panel has been subjected to sunlight without coolant (the tubes were cut before I got there, so I don't know if they were damaged by the high temperatures that would have developed.  Is there any way to tell?  (There doesn't seem to be any liquid in the tubes, just a central tube with metal collectors running from top to bottom).

Thanks, Greg

[betwixt]

Good eyes ?  If only you knew. I'm as blind as a bat without my specs!

It's amazing what difference a large computer screen  makes to seeing small details.

The glass tubes don't contain any liquid, it's the fine pipe inside the tube that holds it. The glass is there to isolate the pipe from the environment and prevent loss through convection into passing air. The ones I use have are double skinned, a bit like one glass tube inside another and the gap is evacuated. On the outside of the inner tube (the outward facing side in the evacuated gap) there is a black coating to absorb the Sun's radiation. The innermost region, inside the inner tube is not evacuated but has a bung fitted to hold the copper pipe and restrict air movement.

The liquid, usually distilled water, is trapped inside the copper pipe and fins and it is highly unlikely it will escape. If any damage does come from overheating it will generally be plastic fitings and insulation that suffers but the system will continue to work subject to some extra heat loss. A word of warning is due: insulate the pipes to and from the manifold but don't use normal foam insulation. The normal stuff is intended to lag pipes to prevent freezing and usually has a melting point of about 80C. If anything goes wrong with your pump and the water doesn't circulate, the foam will melt and make a horrible mess! For the same reason, put a pressure vent in the pipework somewhere so if it does blow steam it does it somewhere safe.

Brian.