Heated Concrete Ideas

[dfitz21]

I have been reading lots of great posts and before I make a mistake in my building I wanted to ask some questions. I am building an automotive shop that is 60' wide and 150' long with 13' ceilings. I planned on installing a waste oil boiler for in concrete floor heat.

The first 30' x 60' will be office space and the rest, 30' - 120' will be automotive shop with 14 garage doors. Here are my questions

1. 1/2 pex, is that what I should use and where is the best place to purchase it from?

2. Do I need to under floor insulation? I priced out 2" 4x8 foam high density panels and I would need 288 of them. Was wondering if there is any other alternative. I was going to possibly use Prodex around the 8' perimeter and maybe something else on the most inside? Any thoughts?

3. It looks like I might need 4x zones. I wanted to locate the boiler in the other end of the building from my office so my waste oil tanks could sit near it and be out of the way. Any thoughts or ideas?

4. My calculations say that a 200k waste oil boiler would suffice but I am thinking maybe the 350k might be a better idea. Local consultant stated that he would rather a 200k running all the rather than a 350k shutting on and off. I was looking at energy logic units but really have no experience with any waste oil boilers.

Thanks
Dan

 

[Streetbu]

Energy Logic are very nice. Ours literally paid for itself in the first 3 months! As far as size, I have no idea. I would have a pro figure it out along with how many zones you need. Make sure to lay the oxygen barrier pex out to leave room for the lifts to be bolted down without drilling thru a line....

 

[yeldogt]

Don't oversize the boiler. Don't go cheap on the insulation. Zone the office separate from the shop.

The losses at the doors will be the greatest -- make sure you have a thermal break. I like the double loops at doors .. but other things work. You want a bit more heat around the open edges -- but not under equipment. Thought should be given to the tube layout -- think about the space -- how it will be used .. where do you want and need the heat. That's where you increase tubing.

Much can be accomplished just laying out the tubing correctly

 

[86turbodsl]

That is a huge building. I doubt you're doing it for your hobbies, so if it's a business, i'd say get a pro to help you out. 1/2" pex likes loop lengths of 300' or shorter, and that's basically one loop from front to back. You'll probably need some manifolds in various areas depending on zoning.

 

[dfitz21]

I was thinking 2 or 4 manifolds, obviously the office has to be on its own and with a length as long as the shop is I think 4 manifolds might be the wisest.

I dont want to oversize the boiler but unfortunately when you talk to energy logic they want to sell you the largest boiler known to man. They oversized the forced air unit it my collision center and it cooks the guys out of the building.

 

[bzinsky]

I have been reading lots of great posts and before I make a mistake in my building I wanted to ask some questions. I am building an automotive shop that is 60' wide and 150' long with 13' ceilings. I planned on installing a waste oil boiler for in concrete floor heat.

The first 30' x 60' will be office space and the rest, 30' - 120' will be automotive shop with 14 garage doors. Here are my questions

1. 1/2 pex, is that what I should use and where is the best place to purchase it from?

2. Do I need to under floor insulation? I priced out 2" 4x8 foam high density panels and I would need 288 of them. Was wondering if there is any other alternative. I was going to possibly use Prodex around the 8' perimeter and maybe something else on the most inside? Any thoughts?

3. It looks like I might need 4x zones. I wanted to locate the boiler in the other end of the building from my office so my waste oil tanks could sit near it and be out of the way. Any thoughts or ideas?

4. My calculations say that a 200k waste oil boiler would suffice but I am thinking maybe the 350k might be a better idea. Local consultant stated that he would rather a 200k running all the rather than a 350k shutting on and off. I was looking at energy logic units but really have no experience with any waste oil boilers.

Thanks
Dan

I've tried sizing my own equipment before, using math and logic and hours of research, I've been wrong a few times. Hvac tech that would lose a spelling bee to a 5th grader nails it with a pen and paper in like 15 seconds.

Just ask someone in the trade their opinion.

 

[yeldogt]

Oversizing is a big problem ... especially when doing radiant and spray foam. The idea with radiant it to get enough pipe under foot to be able to deliver what's needed -- if you do that everybody is happy and it's the cheapest way to heat. A properly heated building will have a ceiling temp at or lower vs the 4' mark .. you can't do that with forced air -- so it requires more BTU's .. also the convection makes you feel colder. A proper radiant job will not have strong convective currents .. with little or no stack effect.

That's why adding a bit more pipe (closer spacing) can make the difference so as to not have to increase water temps.

 

[Climatecreator]

I have been reading lots of great posts and before I make a mistake in my building I wanted to ask some questions. I am building an automotive shop that is 60' wide and 150' long with 13' ceilings. I planned on installing a waste oil boiler for in concrete floor heat.

The first 30' x 60' will be office space and the rest, 30' - 120' will be automotive shop with 14 garage doors. Here are my questions

1. 1/2 pex, is that what I should use and where is the best place to purchase it from?

Best advice, even if you want to do it yourself, get a local company to do a load calc. On bigger jobs most HVAC supply houses will get someone or a local product rep to come out and size the project and do the loop design as well as size the product and decide manifolds quantity and location. They know their products best. You can then use the load to accurately determine boiler size.

2. Do I need to under floor insulation? I priced out 2" 4x8 foam high density panels and I would need 288 of them. Was wondering if there is any other alternative. I was going to possibly use Prodex around the 8' perimeter and maybe something else on the most inside? Any thoughts?

Insulate Insulate and insulate some more. They will need to know what is going in for insulation to size the system.

3. It looks like I might need 4x zones. I wanted to locate the boiler in the other end of the building from my office so my waste oil tanks could sit near it and be out of the way. Any thoughts or ideas?

Again determined by the load calculation.

4. My calculations say that a 200k waste oil boiler would suffice but I am thinking maybe the 350k might be a better idea. Local consultant stated that he would rather a 200k running all the rather than a 350k shutting on and off. I was looking at energy logic units but really have no experience with any waste oil boilers.

Thanks
Dan

Determined by load calc. You definitely DON'T want a boiler short cycling. Longer run cycles are best.

Also as mentioned. Be sure you know where drilling will occur, keep tubing away from it.

No such thing as too much planning here.

Good luck

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[Shop Specialties]

A Clean Burn coil tube boiler is a far more efficient boiler than the Energylogic. I am thinking the Clean Burn CTB 350 would be a good fit for you BUT you really should have a pro design the system and get an accurate BTU number. Have you thought about snow melt for the any sidewalks or areas in front of the doors ?

 

[brewchief]

For that size of building you really need some professional help, you really need a proper heat loss done, that many overhead doors will make a difference, make sure you have the specs on them.

Tubing larger then 1/2" might work out, you will want to leave areas to bolt down your lifts so you will lose some floor area there. Make sure you make provisions for slab sensors in each zone, even if you don't use them at first you may want them later.

None of the roll out under slab insulation that I've seen carries a real R value, they will say it does this or that but if you really read into the installation requirements it can be impossible to install that way.

 

[dfitz21]

It looks like these boilers are only 75% efficient so their output is 150k. The calculated need from online calculators is 198k so maybe the 200 would be small. I didn't know the clean burn was more efficient?

d

 

[walrus]

I don't see the location of the building anywhere?

 

[jack stand]

Like most of the above posts, you won't regret having a radiant company design your whole "system". It will be money well spent.

 

[Shop Specialties]

It looks like these boilers are only 75% efficient so their output is 150k. The calculated need from online calculators is 198k so maybe the 200 would be small. I didn't know the clean burn was more efficient?

d

The Clean Burn is a true 3 pass design over the coil tube with a larger heating surface area as compared to EL. Clean Burn ash cleaning intervals are 2x longer at 1,000 hours compared to the EL every 500 hours. Doors on each end swing open for easy ash cleaning. Clean Burn burner design is far superior and able to burn all synthetic oils due to adjustable preheat block thermostat. EL says oils must have a flash point max of 400*.

I have 27 years of doing nothing but waste oil heater sales AND service. I am not going to sell you anything but I am here to help if I can.

 

[dfitz21]

Building is located in upstate New York, 14456.


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[Gearhead777c]

Spend the money to insulate. Mine is about 3200sqft and used 2" foam under the slab and around the edges flush with top of slab and about 2' deep. I even flashed the foam with 16" of aluminum on the outside to prevent critters chewing their way in. I would consider spray foam as well. I didn't go over 5 loops per manifold and fed each one with 1" copper with its own circ pump. I used 1/2 ALPEX as I felt it was stronger then regular pex and held its shape while bending. I got everything from Pex-Universe and used their everhot brand alpex. Your building a huge shop and some pro advice would be helpful. All I know is my system has been working great here in NY with some cold temps the past 2 weeks.

 

[C10Dan]

I have about 2200 sqft and I'm located between Buffalo and Rochester, NY. I found some reclaimed XPS insulation that I used under my entire slab. It's 4" thick, 40 psi high density. So glad I found it. I also used 4" (25 psi) on the edge of the slab, down feet vertically into ground and covering entire slab edge. I did not spray foam my walls, but have R19 in them. Ceiling is R49. Insulate... Insulate... Insulate.