heat patio with owb

[zsteinmetz]

Ok guys had a brainstorm today about my patio between my garage and my house roughly 400 sq ft. This summer i am going to be tearing it out and pouring new cement and thought why not put radiant heat in it and heat it with my owb. Stupid maybe but no more ice and no more shoveling either. This area seems to get packed down the most anyway so the ice is there for the duration of the year. So anyone know what my cost would be for this. What do i all need? Pumps, tubing, stats etc. Basically im just trying to get a rough estimate of the extra cost of going this route.

 

[kevinj]

Ok guys had a brainstorm today about my patio between my garage and my house roughly 400 sq ft. This summer i am going to be tearing it out and pouring new cement and thought why not put radiant heat in it and heat it with my owb. Stupid maybe but no more ice and no more shoveling either. This area seems to get packed down the most anyway so the ice is there for the duration of the year. So anyone know what my cost would be for this. What do i all need? Pumps, tubing, stats etc. Basically im just trying to get a rough estimate of the extra cost of going this route.

I have NO IDEA of how the OWB works.
But this does sound like a feasable idea.

Also, is it possible to heat the walk area from the driveway to the front porch ??? (Underground)


Maybe, this area can be controlled by valves, on/ off .

Kinda makes sense to me ...

 

[rx7145]

Sure you can. Only problem I see is keeping the lines from freezing when you don't need the slab heated. You would need to keep the slab heated all winter which would use a lot of wood.

 

[zsteinmetz]

im thinking i could use glycol inthe lines so it would never freeze. Same setup as people who have only radiant heat. They have to have an antifreeze in it just in case boiler quit. I just dont know how much extra $ it will be to do this.

 

[kamhillbilly]

im thinking i could use glycol inthe lines so it would never freeze. Same setup as people who have only radiant heat. They have to have an antifreeze in it just in case boiler quit. I just dont know how much extra $ it will be to do this.

If you are tearing it out and pouring new concrete there is only one chance to put lines in even if you dont use them for years .just installing lines dosent cost that much $$.You could use a water to water heat exchanger with glycol in your patio lines

 

[rx7145]

If you are tearing it out and pouring new concrete there is only one chance to put lines in even if you dont use them for years .just installing lines dosent cost that much $$.You could use a water to water heat exchanger with glycol in your patio lines

Good point. A water to water heat exchanger would be a good idea. I say go for it!

 

[ericjeeper]

yeah going to need an exchanger

flat plate, shell in tube or something like and glycol. and a pump.. and expansion tank and a pressure gauge. Barrier pex. keep the loops to under 200 feet each. Lay it out 1 foot on center.. and Make it manual.. So you can run it only when you need to kill the ice or snow.. It is going to suck the life out of that boiler when it is running.

 

[zsteinmetz]

Keep it coming guys. Jeeper you say shell in tube. What does this mean? Why will it suck the life out of my boiler? Is it because im trying to heat up a cold block of cement? Yes it will take some wood but usually it snows when it is about 20 to 30 degrees out so i figure turn it on for a while once its done shut it off. My boiler is sized plenty big to do it and i would put down 2 inch foam under the cement. To run it say today when it is -5 would be insane. I plan on putting in floor in my kitchen also could these be on the same pressure tank and pump.

 

[grandpatractor]

You'll also need some kind of valve to limit the temp of the water going into the cement. I can't think of the proper name right now:bang:
It blends the incoming hot water with the outgoing cold to keep the temp down around 100-120. 180 going into cement is not good.

 

[zsteinmetz]

a mixing valve right. I was thinking of hooking it on the return side of my stove. Right now i go from the stove to the furnace then the water heater then back to stove. So i would add the flat plate exchanger after these two since 180 degree water is not needed.

 

[Ken05]

Yeah grandpatractor is on the right track. - tempering valve - . If you just let hot water fly that concrete will crack up into tiny pieces. The warm up has to be very gradual.
Asphault may be better suited for this purpose.

 

[ktm250rider]

You've only got to keep the concrete just above freezing to keep the snow off of it. Say around 40°. SHouldnt be too bad on wood. When you pour the slap, put in a piece of PEX so that you can slide a thermocouple into it when the slab has cured. Then you can measure the temp of the slab and control that.

 

[Khtsr44]

Padio

Go for it, 2" foam good way to go, use rebar, forget wire. 8-12" spacing on tube. Use a ball valve for on off and flow control. Run it off your kitchen manifold and pump. Put the system in now you can worry about hooking it up later. Heat exchanger it you use anti freeze. Don't worry about 180* water hurting you slab it won't. If you use a heat exchanger you will need a separate pump. NOW Go have a beer and think about it.
It's not rocket science.
Ken

 

[windthrown]

Yah, I wish the carport slab here was poured with a hydronic loop in it. I could de-ice the thing in cold snaps. Also when a warm front hits after a cold spell, the condensation is really bad and water builds up all over the slab (concrete colder than ambient air). I could heat the slab and get rid of the water. Also warm the carport to work out there in cold weather. Radiant heat is really nice to keep warm.

All the rest of the above options/advice sound good, like the flat plate Hx on the slab loop. One thing about antifreeze in the boiler loop is that it is not as good a heat conductor as water. If you have to use antifreeze, use propylene glycol, and not ethylene glycol (highly toxic).

 

[zsteinmetz]

Talkin to the wood doctor salesman tonight guys and he said in my kitchen where im gonna be using staple up pex radiant heat underneath the floor joists to just run the water from the boiler through this instead of a closed loop for the boiler and a separate for the in floor. Im not saying for the patio also but just the inside rooms. would this be ok or should you use a seperate loop? Either way i need a pump but i could get away without the expansion take and manifolds. And what about the patio could i do the same here but put in a mixing valve ?