Dumb heating element and water pump

[Quattrohead]

I'm going to suggest you ditch the radiant heating entirely and use mini splits instead. They are mega efficient and quite simple to get up and running on solar.
But first of all, insulate the building. It's not fun or sexy but it is by far your best investment.

 

[Zwy]

I'm going to suggest you ditch the radiant heating entirely and use mini splits instead. They are mega efficient and quite simple to get up and running on solar.
But first of all, insulate the building. It's not fun or sexy but it is by far your best investment.

Entirely off mini splits probably works in FL, not so good here.

The trend I see now is air to water heat pumps and this is used for radiant heating. This is done with thermal storage and if you look at John Siegenthaler's training material, it shows this is the trend. I run radiant floor heat in my shop using a condensing boiler. The system has worked great for about 12 years now. I'm heating 4400 sq feet with 18 foot ceiling with about 900 gallons all season with shop temp at 70F.

But back to the thermal storage. The heat source can be multiple sources, direct electric, gas condensing boiler, oil boiler, biomass and ground source or air to water heat pump. I'm currently in planning and acquisition stage of a project to heat my house. Tomorrow I will be picking up a pair of 525 gallon boiler tanks for thermal storage. I can use these in conjunction with any of the heat sources listed above.

 

[Buckshott]

I built this system about 8 years ago. It is closed loop, the source is a 75 gallon propane water heater which also provides domestic HW.
It is heating a 6" slab in a 1200 sf attached garage which is insulated. Nothing fancy with insulation, just 6" walls with batting, R38 (I believe) in the ceiling. Floor has 1 1/2" foam board under and 3" around sides/edges. I am located in the inland NW, so pretty cold temps in winter (-20 is not unusual).
I set it at 62 when I know I'm going to be working on projects for several days or weeks and back it down to 55 if I don't plan on being out there much. Floor heats up at about 1 degree per hour. It's not to bad to run like this (cost wise) but if I run it up to 70F or higher it goes through the propane rapidly. Running it the way I do (55 - 62) I use about 1000 gallons of propane a year. I love this system and it has worked flawlessly. I have always thought it would be really cool to have an alternative source of heat for my system such as PV or even better have PV as the primary source and propane as backup. I am very interested to see what you come up with. Please keep us posted with your progress. That is a beautiful shop you are building.

 

[Daddy Tanuki]

Right now it's just the manifold capped off holding pressure. I can rig up a pump pretty easily to circulate water, just the main problem is making it warm.

You have a point, I should just experiment with ac power first. But it's not good for the long term. Even if a 1000w heating element is running 24/7 that's ~9a or 24kwh per day, for 30 days, at $0.19/kwh that's $136.8/mo. That's a lot of juice.

1000w is also fairly low, which is why I was thinking 2-3 strings of panels each being 1200w each that will blast it with heat. Like I said I am not looking for a balmy 70f, I just don't want my feet to be freezing on an ice cold concrete floor.

maybe a stupid question, but why not build a cheap water boiler using firewood for the duration? you live in Penn... plenty of wood to burn especially since this is not a fireplace or wood stove where you need to worry about creosote buildup. a tank that you can build a fire around and a pump...

then when you have the time/cash/whatever you can convert to whatever your original plan was