I’m in the planning stages of a new shop. I was thinking about it a while ago, and solar heat seems ideal for a shop. I’m not incredibly temperature sensitive out there, the low temps are ideal for solar, and there’s is little need for air conditioning and other things that conditioned spaces require. I am wanting a find a book or something on this so I can learn moreabout proper sizing. I’m thinking it would be a dry system with buffer tank so it can just sit in the summer without being used. It would be nice if it could maintain 45-70 degrees in the shop and i could supplement with a unit heater or wood stove as necessary. Has anyone done this? I see few resources available.
Solar radiant heated shop
- Thread starter wanderer
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TurnipTruck
Well-known member
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Look at the link at end of this post for my build. I built my shop with solar in mind. It works well. The lowest temp I've seen is 39, generally it keeps it around 50. If I had used professional collectors instead of homemade I'm sure it would do better. www.builditsolar.com s a good resource
Solar thermal is pretty much dead when you get the numbers. Better to put money into photovoltaics and get a return. I hate saying that as I was in the solar business back in the 70's and did a lot of solar thermal systems. I think we used a figure of 3.68 gal/sq ft of collector. That was for a higher temp system however so you could increase the amount of storage for a lower temp system.
ard
Well-known member
I know, right?
Solar thermal is easy DIY project and its simple to maintain.
This is the part I guess I don’t understand. Seems like I would have 10 or $15,000 worth of materials and a few weekends worth of time to get something like this hooked up. Most of the labor would be below the slab anyway, right? This all seems very reasonable to me if the expected outcome were a properly designed system that could save me a few thousand dollars per year in energy cost.
What I am asking for his help getting the components matched properly so that I get a desirable outcome for the money spent. Solar cells really don’t appeal to me because of the 25 year life span. Also they are quite expensive.
I’ve done some reading on this. It seems like it would be a good design feature. In my case I don’t know how effective it will be because of the limited Southern exposure. I’m thinking these design elements would be quite Obtrusive on a larger barn with tall sidewalls.
BillK
Well-known member
It would be nice to know where you are located in order to answer the question better. Alaska would need a totally different system compared to Florida.
I don't have 10 or 15,000 dollars in mine unless you include the slab which I was going to pour anyway. I don't have an exact dollar figure but somewhere between 2 or 3 thousand. If you add my labor about 70 million
I bought fittings off EBay, I bought the radiant floor parts off internet, I set up slab, laid out Pex, built collector into side wall of my shop but I built my shop with solar in mind. Insulation, tightness and orientation were all thought of with solar in mind. Was it worth it?? To me it is as its warm in there today with me doing nothing. BTW 20 degrees and wind blowing hard. This time of year solar hot water shines. If I wanted I could stick a boiler in there and heat the floor with oil or propane.
Depending where you are and how big shop is. Solar PV and mini split heat pump may be a good combination.
Denwood
Well-known member
Walrus, can you post in your build thread an overview of the control setup you came up with? I know you've been pumping BTUs into your slab for a few yrs now.
Changes you would make?
Changes you would make?
You might look at this site: http://www.heliodyne.com/heliodyne-products/ I installed a lot of their products 40 years ago, but they are one of the few who lasted and their products were some of the best. Also Viessmann and Bosch have solar products. These will all be higher dollar collectors, but you can get a sense of what is involved. You want high quality collectors. Solar radiant is perhaps the best of the wet solar applications as you get the highest efficiency from the collectors due to the low temp of the system. Your first step is to do a solar map of your location, which apparently you insist upon keeping a closely guarded secret. You can download assorted apps for solar mapping. Before you go forward you might look at some pro help with system design. You will need the collectors, mounts, storage tank, circulators, temp controls and slab temp controls. If you are on a grade you can locate the collectors below the building and thermosiphon to the tank. You can have substantial parasitic electrical consumption in pump costs.
NE Kansas. Predominately heating area. Wasn't planning to cool. Figure the shop will need 40k BTU to maintain temp, but not so worried about the final temp. Might use that as a design number, or slightly lower so I don't have to worry about heat cump on fall or spring days (where does this heat go anyway?).
Zero bucks, can leave the doors up or partially down, also get great 
light. Gotta have the southern orientation.
10 degrees outside, 65 inside. By 2pm gotta open man door to vent. Pop em off for summer. Hang em on shed ext. wall out of the way.
.left over 2x4s and scrap cheap greenhouse glazing. Shoulda done it 20 yrs, ago.
light. Gotta have the southern orientation.10 degrees outside, 65 inside. By 2pm gotta open man door to vent. Pop em off for summer. Hang em on shed ext. wall out of the way.
.left over 2x4s and scrap cheap greenhouse glazing. Shoulda done it 20 yrs, ago.
Mr onetwo
Well-known member
Great idea, you should start a new thread and give us more details and pictures.Zero bucks, can leave the doors up or partially down, also get great
10 degrees outside, 65 inside. By 2pm gotta open man door to vent. Pop em off for summer. Hang em on shed ext. wall out of the way.
.left over 2x4s and scrap cheap greenhouse glazing. Shoulda done it 20 yrs, ago.
I have thought about doing some sort of solar "breadbox" type hot air collector over my overhead door. I have perfect southern exposure.So many projects, so little time or money!Attachments
I'm using a commercial controller, it turns pump on at 15 degrees above slab temp and off at 5 degrees above. I can't remember the name. The one I started with was cheap but a pain as you had to hook a laptop to it to see what was going on. The cost was 250 or so?
One thing I would have done was move slab temp sensor further out away from where all the tubes converge at manifold. That part of slab is warmer than rest of slab. I put 8 feet of conduit in there with the bend up its only 6 feet away from manifold. Should have put 15 or 20 ft of conduit in there. Not sure it really matters but....
I've known other folks who have used a small PV panel to power pump, suns out pump turns on. Not sure how that does but they are out there.
Zero bucks, can leave the doors up or partially down, also get great
10 degrees outside, 65 inside. By 2pm gotta open man door to vent. Pop em off for summer. Hang em on shed ext. wall out of the way.
.left over 2x4s and scrap cheap greenhouse glazing. Shoulda done it 20 yrs, ago.
This is a pretty cool idea. I wonder if there is a way to integrate these into the garage door? Properly designed maybe not necessary to remove for summer?
Solar thermal in the summer either goes to dhw or stagnates. It is one problem with thermal. If you don't have a use for it, it sits. That is one of the other reasons solar electric can pay better. You are in the planning stages. At least look at the numbers for the PV's. Wholesalesolar.com is a good site.
Walrus, are you running storage on your system or is it piped direct to the slab?
Walrus, are you running storage on your system or is it piped direct to the slab?
The heat goes somewhere, right? With no flow it would boil the water, flashing into steam.
I have a quotation on a solar project for my house. 9.7kw, $25k. Projected to be a ten year payback, but they projected HUGE increases in electric rates to make those numbers work out. Personally, I don't see it. Generating power is cheap, what is expensive is the infrastructure. In the future what will go up is the connection fee, not the rate. Grid tie solar still need the connection, so the projections they are making are a false comparison.
Directly to slab, simple system. Summer is no issue as panel is built into wall. I cover with it plastic tarp and turn pump off.
If you have a pressurized collector system, meaning fluid in the collectors, the system cooks big time in the summer. If it is a drain-down system then the collectors bake or you cover them. Roof mounts become problematic. The heat either goes into the fluid or into the collectors. My hat is off to Walrus. His is about the simplest system you can have. He protects the collectors in summer and has minimal tech issues that can come up. And, it works for him.
As to the PV and the economics, I understand your skepticism, but if you do a grid tied system for a while and battery technology/cost gets there you can then go direct for at least a part of your load. Summer days are much longer than winter days and you take advantage of every bit of available sunshine. Net/net, if you cannot answer some of the hydronic challenges of solar I think you will be better off with a conventional radiant system, insulate the hell out of the place, buy large LP storage tanks and negotiate with your supplier for pricing.
As to the PV and the economics, I understand your skepticism, but if you do a grid tied system for a while and battery technology/cost gets there you can then go direct for at least a part of your load. Summer days are much longer than winter days and you take advantage of every bit of available sunshine. Net/net, if you cannot answer some of the hydronic challenges of solar I think you will be better off with a conventional radiant system, insulate the hell out of the place, buy large LP storage tanks and negotiate with your supplier for pricing.
larry4406
Well-known member
Walrus - can you provide a direct link to your system? I can't seem to find it.
kj_mustang
Well-known member
Larry4406,
Walrus posted two posts before you. Look at his signature line on that post, it has a link to his build.
Walrus posted two posts before you. Look at his signature line on that post, it has a link to his build.