BobbyBass solar collector

[Tom7227]

I've read and saved every one of your musings about Lakeiwanttobethere and I think i remember you writing about a solar heat collector you have on your house. Could you give me some details on what you have, how well it works, cost - whatever you have time to tell. A relative is thinking about making one out of beer cans that he saw on the Net and I think there's a lot to be learned about the whole area.

Send me a PM if you would prefer.

Thanks for your time.

Tom

[Bobby Bass]

Tom, yes I do have a solar collator on the South side of my house and also a greenhouse that I added a few years ago that is connected to the solar collector. I have seen the beer can approach but I think my way is more efficient, cheaper and a lot less work then the beer can method. My setup has been in place for about twenty years and keeping track of the heat gain it saves me about 200 gallons of fuel oil a year which can add up to some serious pocket change.

My collector is 4x12 feet and hangs on the house on the South side. Right now it is functioning as a summer cooling system, I will explain later. Since I originally built it I have made some upgrades as I originally got some 4x4 thermopane windows for free, the glazing is the most expensive part of a solar collator system. I have since gone to Coverlite which is a clear high quality rigid plastic. Basically what I did was make a wood frame out of 2x6 4x12 feet and attached this to the side of my house after removing the siding to get to the sheeting.

Next step was to install 2.5 inches of sheet rock which is used for thermal mass and cover the exposed house wall inside the wood frame. Over the top of the sheet rock an inch spacer board (Cedar) is fasten to the sheet rock every 3 feet or so, this is added so you have some where to attach a 4x12 section of dark painted sheet metal, this is the part of your collector that get hot.

For my installation I then drilled two four inch holes through the sheet rock and through the house wall into my living room. One hole in each upper corner. In the basement I drilled a 3rd hole which enters the collector in the bottom, center. The collector is then covered in the Coverlite and trimmed out, caulk edges and in my case I added a cedar shake roof to the top of the collector so it matches my house. The mechanical part of the collector is very simply. I ducted a cheap bathroom exhaust fan in the basement to the hole in the bottom of the collector. The fan is on a timer. When the fan engages it forces air (50cfm) into the collector which then pushes the heated air into the house through the top two vents. I think of the top of my head I get two total air exchanges per minute. The air from the basement is about 55 degrees and the air vented into the house will be as high as 120 degrees which is comparable to a forced air furnace.

Four years ago I added a utility building to the side of my house which is a mufti purpose building. The building stands 4x12 feet and is heavily insulated with glass front windows. It to has a powered air supply feed from the basement. The air which enters the green house is heated to 90 degrees and it is exhausted into the solar collector supplying preheated air for the collector to warm even more as it is pushed across the metal plate. Air turn over in this building is once every 7 minutes, between the two systems I am getting 100 CFM of heated free air. The collector is most efficient in spring and fall as we just don't have a lot of day light in mid winter.

The Solar box as we call it is also used as a green house nursery for the plants here as we can plant in there and pipe in basement air that is never colder then 55. In the summer the timers are set to run at night and the windows in the green house are left open. This gives us another source of cool night air into the house and gives us air exchange in the basement at the same time. Solar collector is cover during the summer to keep it out of the sun and we have planted apple trees to shade the area. The solar building has 12 inches of insulation in the roof, 3.5 inches in the wall, sheet rocked and the entire interior is covered in foil faced insulation. This adds more insulation and also lets light bounce to all corners of the building for plant growing. The floor is made of plywood with foam sandwiched. The top of the floor is covered in paving bricks to add even more storage mass for heat gain. There is also sheet rock painted black on the back wall for more heat gain, it is not attached directly as there are spacers so the air can flow on all side of the mass. Come fall we will move planters of tomatoes and peppers inside to extend our growing season well in November

I suppose someday I should just make a video of it as I get enough questions from the utility guys who see it and want to know how it works. Here are a few pictures as they always say more by themselves.

Mother Earth ran an article a few years back that shows my idea almost to a tee, they also said that any solar project that can raise the heat by 40 degrees is a success, I got that beat easy ! Hope this helps you out and or gives someone else an idea, Bobby

covered solar collector

Free standing greenhouse/preheater for collector

Inside greenhouse, fan pulls heated air from ceiling and is piped to solar collector. You can see the foil faced walls, black sheet rock for heat collection.

[Tom7227]

Thanks for your reply.

The beer can videos that I have seen really don't give enough info to make a decision on whether the devices work well enough to make a real difference or what the cost/benefit would be.

I seems to me that more benefit could be achieved if the unit heated an ethylene glycol water solution. It would be easier to get the heat where you wanted it and with some minimal effort you could set up some storage tanks out of plastic 30 gallon drums or even discarded surge tanks of the old galvanized variety. Setting some sort of limit switch and thermostat in the system would keep it from running when it was too cold.

Obviously you're well satisfied with your setup. And it works for you in large part because you have the room and the buildings to use it.

Maybe others would like to join in and give their perspectives on these types of devices.

Thanks again.

Tom

[Bobby Bass]

Just the tip of the iceberg talking about solar heat. I would consider my setup as a passive unit even though I use blowers to move air. As far as bang for the buck it would be hard to beat for the original system. When you start talking liquid storage units you are starting to talk about mass and a lot of area to collect heat to convert the liquid and then store it. Water is the best mass collector but in our area it has to be insulated to maintain and reduce heat loss. If you were down south most of that problem could be reduced.

I have looked into the alum can collection to add inside my unit but it looks to be a real pain cutting can top and then securing them together to form pipes. I have no doubt that the alum would be a good way to collect heat but you are talking hundreds if not thousands of cans. I wish I had more exposure available on my house I would expand my unit but when I remodeled I put a lot of windows on that side of the house, almost 65% of my total glass in the house. Of course that was 25 years ago so I have been playing with solar for awhile. I to would like to see and hear about anyone else who is adding solar or has it, Bobby

Something I forgot to add is that I have remote thermometers in both the greenhouse and collector along with another one at the point where the air enters the house. I can monitor them right here at my desk and two switches control all the blowers so it is not a deal to control when they are running. Hard to believe that it is not always sunny here at Lake Iwanttobethere

[leechlake]

thanks guys! Our cabin faces South and now I'm engineering doing this project with my engineer father in law. I'd wager a combination of 6 less walleyes will be caught, 2 grouse, a few ducks, and maybe the buck of a lifetime since I will be tinkering with this new project during Sept and October. I guess I'll be saving the earth and conserving our fish and game at the same time.

Looks like a pretty easy build and will just need to tinker with some details and the normal issues that come up with any project. Looking forward to seeing what it saves us in heat bills

[BoxMN]

Please take some pics as you build it, as I know I would love to learn more and see in process steps. I am not a builder or engineer, so baby steps appreciated

[Tom7227]

There are a bunch of videos on youtube that you can check out