Solar radiant Heat

[randydupree]

i called several places for quotes on the tubing and valving,one company wanted $25,000 for all kinds of stuff i didnt want or need.
i went with another company for less than $3000.
i can't remember who it was..

 

[philbuilt]

randydupree,
Did you install yourself? Do you use floor temp sensors on you thermostats? What is your heat source?
My pricing on the radiant part was around $5000.00 for all the tubing manifolds, circulaters for 3 zones , and the controls.

The install of the solar equipment on the basement half is all tied in. The pleasant surprise was that the 120 gal. storage tank has an electric heat element in it as well. Connecting that could be an option should oil prices continue to go up.

When connecting the Line's from the panels I was surprised that the ports on the tank that I received were 3/4" and not 1". All the piping so far has been 1". The tank being 3/4" meant that I reduce in and out of the tank. I checked with Radiantec and they said that this was the norm . The hot water out of this tank will feed the cold water in of my current superstore as a preheat. The hot out of the superstore will feed the domestic hot and circulate back thru the floor heat exchanger and return to the 120.

Today the plan is to install the panels and hopefully charge the system.

 

[randydupree]

my project is not done yet,but so far i have done it all myself.
my wife and i put all the tubing in 3500SF of floor, but first we put down 3/4'' foam,then wire,then the pex was tied to the wire,then we paid to have the 100 yards of concrete poured.

we are using solar panels and geo-thermal to heat the water,the geo-thermal will also run the heat pumps for the AC units.
i have 7 big panels that just may be too many for south Ga.
but i bought them all at yard sales and through craigslist.

i plan on having 3 big storage tanks with elec. elements in them,backup heat,just in case.

in the summer i'll run the geo-thermal water through the floor to help cool the building,cool water,not cold.
it may not make the floor sweat,or it may,nobody can really tell me,if i can keep the floor temps constant i'll be happy and it won't sweat.

i do have floor temp sensors in 2 places in the building.
i only have two zones,i see no reason for more,the floors will all equalize,right?

 

[ampsucker]

couple of thoughts on your last post.

floor condensation is simple to predict. condensation occurs when the temperature of a surface is lower than the dew point of the air around it. the dew point is dependent on the relative humidity. using typical numbers, if you keep your concrete floor at 70 degrees and the dewpoint of the air in your home is 72 degrees, you'll get condensation. several variables might affect this. choice of floor covering for example. you want a reasonably good conductor since you want the heat to come up in the winter. a very thick carpet is out, thinner, harder materials are better. these are the same ones that will allow condensation to form on their surface. the solution is to use either a dehumidifer to lower the dewpoint to below the temp of the floor or run the a/c enough to keep the air dehumdified. i'd probably choose option 2. to prevent mold growth, the target for relative humidity level is around 50% or lower. a properly sized a/c can do this (meaning, it runs constantly on the hottest days with little or no cycling off and on). the dewpoint at 50% relative humidity will be close to the temp of the a/c evap coils or about 20 degrees below ambient (50 degrees or so?).

i would be surprised if you get much benefit from cooling the floor in the summer anyway. it being mostly underground, it is going to be the coolest part of the house, so keeping the temp at head level around 70, you aren't going to see much benefit from cooling the floor since you can't cool it below the dew point without condensation and any cooling you do accomplish is going to stay put right at the floor anyway.

another possible source of moisture is the concrete itself. concrete can wick up moisture from the sides and bottom. you mentioned insulation, but didn't mention a vapor barrier. if you did the pour without a good vapor barrier, you might be able to paint or otherwise seal the surface of the concrete before adding the floor to keep wicking to a minimum.

regarding zoning, i think the main advantage of zoning is to control the temps more precisely and save even more on energy by not heating spaces that don't need to be heated. for example, you might zone the kitchen and utility rooms so you can change the setpoint since they already have heat sources in them. (if you cook a lot, run the dryer, have hot water heater separately, etc.) radiant heat being slower to respond, will not allow you to turn down a room that you won't be using for several hours or anything like that, but you could shut off bedrooms that aren't being used for long periods or rooms with fireplaces, etc.

lots of good information here. my wife informed me that she was ready to start thinking about adding on to the house. (i assume that means she is thinking of more kids weather i am ready or have my outside projects done or not!) anyway, no matter what the new section looks like and no matter when it finally gets done, it WILL have radiant floor heat.

 

[randydupree]

for what its worth my building is built like a loading dock,48'' high.
its packed Ga red dirt/clay and its been there for over 100 years.
on top of the dirt is 4-8'' of old concrete,then i put down the foam,then the fresh concrete,4'' in the thin spots and up to 10'' in others,the original floor was not all that level.
the building is 100'X 80',we are heating about 3500sf.

the ac units will run most of the time for 7-8 months at a time,the heat not so much,figure jan.-feb.and march for sure.

 

[philbuilt]

Randydupree, 80 x100
Is that your future new home or a work shop?

ampsucker,
Thanks for the clearafication I was also wondering if the floor cooling would be an issue.

I did get the panel up and piped in and pressure tested. I will post some pics tomorrow night. and I had to do a tractor mod.
Phil

 

[randydupree]

the home and shop will share the building.
i have 2 pole barns out back too,20' X 100' each.
and on the end of the main bulding theres a 20' X 80' shed,thats going to be my bus barn.

 

[philbuilt]

Here we go:
I had to fab a box to house the heat exchanger for the radiant floor.
2) the box cut into the plywood wall mount.
3) the heat exchanger tied into the old system. This thing did not want to seal at the connections. I had to redo this about 3 times. I finally change to brass threaded unions.
4) the panels tied into the 120 gal tank


Okay now I had to lift the panels up on to the steel frame and the tractor would not reach. So a tractor mod was in order.
1)I welded a reese receiver to the top of the bucket.
2) I drill a match hole in a 2"x 2" x 1/4" sq tube.
3) the tube is 10' with a plate welded at the end for a connector.
4) the first panel ready for transport to the frame. 120 LBS. I built it with the intent that I could add reinforcements in the future.


1) veiw from the drivers seat.
2) lifting to set panel #1
3) panel #2
4) panel #3 the cardboard is on there to keep the heat to a minimum till I get water in the system.


Next was running the copper pipes and sweating all the connections and running the wires.
1) the heat sensors
2) the sensors mntd. at the out pipe at the top of the panel. I install 2 one that is connected to the controller and the other is there just in case
the first one fails. a third is installed at the bottom of the storage tank out for a temp differantial.
3)the insulation of the pipe at the panels this is not complete but i wil finish this coming weekend.
4) The panels uncovered and pressure tested and the antifreeze pumped in.


I then connected the electrical and turn the system on.
The temp out side this evening was 61degs. and cloudy. the panels were uncovere for 2 hours before I turned the system on. Here is the good news The temp at the top of the panels was 74 and at the bottom of the tank coil 64Deg. the circulator started and the top temp whent to 84Deds. this was at 6:30 pm EST no sun and cool out.
After about a 1/2 hr. the water was at 74Degs at the panel and 64 at the tank.
I will post as the week goes on.

Phil

 

[randydupree]

i'm way behind you on the project,keep us informed!

 

[philbuilt]

Today started with rain till 1pm and even in the rain the temp went up.
5:20 am 59.5 top 63.9 bottom 59 degs outside
9:00 am 80.1 top 70.1 bottom 61 outside and still raining
12:00 pm 84.5 top 73.1 bottom 62 outside and raining
2:10 pm 94 top 78 bottom 63 out and clouds
4:30 pm