Complex Heating Scenario

[phaywood]

I recently moved (almost 2 years ago) to a rural property in Southern Indiana. I live in a small 1000sf home with my wife and 2 children and I have a customer cabinet shop also on the property. The shop is about 6500sf total area. Because of the unusually cold winter and high LP prices, I installed a small wood stove in the house and it worked great. Unfortunately, the shop isn't a great candidate for a wood stove because of size, combustibles, etc. I'm considering an outdoor wood furnace to heat the home, shop, or both.

Unfortunately, I can't install radiant floor heating in the shop because there is no piping in the slab. Therefore, I think I'm limited to a forced air heat exchanger. The major complication is a high volume dust collection system that is constantly pumping all of my warm air outside. Because of this, a forced air system seems very inefficient. I'm currently using an LP-fired furnace which is incredibly expensive during the winter months.

I have considered Infrared Tube Heaters, but they would still be LP fired. Does anyone know of a wood-fired Infrared tube heater? Is this even possible?

Our property includes 40 acres of forest so I think we won't have a problem with firewood supply. I would appreciate any suggestions. This recent winter cost nearly $5k in propane costs; therefore, I think I could look into some pretty nice solutions for cost payback...

 

[m67tang]

I recently moved (almost 2 years ago) to a rural property in Southern Indiana. I live in a small 1000sf home with my wife and 2 children and I have a customer cabinet shop also on the property. The shop is about 6500sf total area. Because of the unusually cold winter and high LP prices, I installed a small wood stove in the house and it worked great. Unfortunately, the shop isn't a great candidate for a wood stove because of size, combustibles, etc. I'm considering an outdoor wood furnace to heat the home, shop, or both.

Unfortunately, I can't install radiant floor heating in the shop because there is no piping in the slab. Therefore, I think I'm limited to a forced air heat exchanger. The major complication is a high volume dust collection system that is constantly pumping all of my warm air outside. Because of this, a forced air system seems very inefficient. I'm currently using an LP-fired furnace which is incredibly expensive during the winter months.

I have considered Infrared Tube Heaters, but they would still be LP fired. Does anyone know of a wood-fired Infrared tube heater? Is this even possible?

Our property includes 40 acres of forest so I think we won't have a problem with firewood supply. I would appreciate any suggestions. This recent winter cost nearly $5k in propane costs; therefore, I think I could look into some pretty nice solutions for cost payback...

Indiana regulates outdoor wood boilers FWIW... So going to a EPA wood boiler is costly!
That being said how about air handlers using hydronic heat from a wood boiler. Just hang an air handler wherever needed to provide adequate heat.

 

[GENECOP]

Pumping all of your hot air outside? If I am reading this correctly there is NO type of heating system that would be efficient .....sounds like the first problem that needs to be solved is to stop pumping your heat out of your space....

 

[Willman]

If there is enough ceiling height I would foam board the slab and run pex in an elevated floor. Radiant heat is the smartest option with the constant dust collection.Warm the objects in the shop not the air. Not enough ceiling height. You can run the tubes in the walls or ceiling or both.

 

[Tonttu]

In your shop, could you place a concrete topping on top of the existing concrete slab on grade to contain new hydronic piping?

 

[phaywood]

You are understanding correctly - the dust collection system does exhaust warm air to the outside. Unless I heat the shop 24/7 to a high temperature, then the objects in the shop remain fairly cold. By using infrared heat, the objects themselves are heated and the air remains pretty cool. I'm certainly not trying to be argumentative on this site, I know that infrared would be the most efficient but I also pay for the LP.

I cannot put hydronic in the floor because I drive a forklift on it and I don't want to pour another 6" slab on top of the existing. I am interested in placing hydronic tubes in the ceiling; has anyone done this? I certainly like the idea of hydronic but I'd never heard of placing tubes on the ceiling / walls.

 

[Frozen Canuck]

Sounds like a bag house for the dust collection system so you can keep your warm air inside might be your best investment. Has to be the best ROI for sure.

 

[Tonttu]

You are understanding correctly - the dust collection system does exhaust warm air to the outside. Unless I heat the shop 24/7 to a high temperature, then the objects in the shop remain fairly cold. By using infrared heat, the objects themselves are heated and the air remains pretty cool. I'm certainly not trying to be argumentative on this site, I know that infrared would be the most efficient but I also pay for the LP.

I cannot put hydronic in the floor because I drive a forklift on it and I don't want to pour another 6" slab on top of the existing. I am interested in placing hydronic tubes in the ceiling; has anyone done this? I certainly like the idea of hydronic but I'd never heard of placing tubes on the ceiling / walls.

I'm not an expert at hydronic line sizes or the like, but on commercial buildings they often have snow melting lines in ramps to the underground parking garages...there the lines are placed in about 3" of concrete on top of a concrete slab on grade, so possibly you could get away with less than 6" of new concrete (depends upon your forklift wheel loads). I did a building review a few years back, an old hospital building, and there they had hydronic lines in the plaster ceiling (building was circa early 1960's) - best to consult with a mechanical engineer for your specific conditions.

 

[Bob Rohr]

I'm not an expert at hydronic line sizes or the like, but on commercial buildings they often have snow melting lines in ramps to the underground parking garages...there the lines are placed in about 3" of concrete on top of a concrete slab on grade, so possibly you could get away with less than 6" of new concrete (depends upon your forklift wheel loads). I did a building review a few years back, an old hospital building, and there they had hydronic lines in the plaster ceiling (building was circa early 1960's) - best to consult with a mechanical engineer for your specific conditions.

A slab over pour would need at least 2" of foam under and all around the edge.

Ceiling radiant works well. I installed a ceiling system in an auto body shop with 12' ceilings. It had a metal ceiling that I attached copper tube to. The added additional blow in insulation above the ceiling. This ran with the same 120 F supply temperature as the radiant floor in another part of the shop.

Quiet, clean, no air movement , fast responding, and still the radiant comfort. The only drawback is the heat doesn't warm under the vehicles like radiant floors

 

[GENECOP]

You are understanding correctly - the dust collection system does exhaust warm air to the outside. Unless I heat the shop 24/7 to a high temperature, then the objects in the shop remain fairly cold. By using infrared heat, the objects themselves are heated and the air remains pretty cool. I'm certainly not trying to be argumentative on this site, I know that infrared would be the most efficient but I also pay for the LP.

I cannot put hydronic in the floor because I drive a forklift on it and I don't want to pour another 6" slab on top of the existing. I am interested in placing hydronic tubes in the ceiling; has anyone done this? I certainly like the idea of hydronic but I'd never heard of placing tubes on the ceiling / walls.

Yes I have, 25-30 years ago did a residential job, conditions prohibited radiant on the floor, we installed radiant on the walls and ceilings behind the Sheetrock.....Walls and ceilings got insulated first, next we installed aluminum panels with a groove, between the framing,,,the thin aluminum panels where secured to the face of the framing.....Next the tubing was snapped into the face of the panel.....Sheetrock was then installed......CAREFULLY screwed off , like I said 25-30 years ago, I still work in the home,,(believe it or not) she has been happy with the job, it was in her master bedroom...her only comment was that the metal panels creaked a bit when system first warms up....I dont remember the brand I used but you can do a search ....good luck...

 

[infinitymike]

What if you glued and bolted 2x4's on the floor at 16" centers, laid in 3/4" rigid insulation and 3/4"warm board with the grooves for the radiant tubing, than glued and screwed 3/4" plywood over that. I'm sure a forklift could drive over that with out any issues.
If you are concerned put a second layer of 3/4" plywood reversing the direction.

(broken link removed)

I know this is different, but I have laid a single layer of 3/4" plywood on the grass to have 30 yard dumpster trucks drive in and out with the dumpsters and not trash the lawn on a job we were doing and it held up pretty good.

 

[phaywood]

Thanks for all of the replies. I really don't want to pour any more concrete or lay a subfloor over the exising slab. I'm going to price out a hydronic system for the walls / ceiling. If it's cost prohibitive, then I'll likely just use a ceiling-hung air handler with a hydronic heat exchanger. I'm also exploring filtering my dust collection system inside. The reason I'd like to avoid that is for indoor air quality - even with excellent filtration, venting to the outside is still the best. Also the amount of filtration would take up valuable indoor space.

Thanks again. I'll post again when I move forward with this project. I'm hoping to do something this fall before it gets really cold again.

 

[flyingcow]

Bob rohr has the best idea. they would boiler will perform the best was this verse is an air handler. In my opinion

 

[bob burke]

I have a cabinet shop too. I have a large wood stove in a shed outside, and I pull the heat inside with a blower. The wall that the shed is built against, is brick...which helps with warmth.

If you're running dust collection, then you're making money. Good for you. Do you have the collection system for all of your tooling, or just for table saws? You don't run the fans all day...do you? Exhaust is def. an issue in the shop, as you are literally sucking money out the vent. If you get/build a big enough stove, you can really make some heat...and you can burn scraps instead of paying to get rid of them.

 

[arbutus]

It takes space, but that indoor collector room or attached collector shed will be the best thing for your shop.

 

[maple1]

they would boiler will perform the best was this verse is an air handler.

 

[heaterman]

We did a cabinet shop last fall with a forced air setup and it works great. You just have to realize that there is no way to overcome the constant makeup air other than brute horsepower. We hung 3-170,000btu hot water air handlers in the shop (about the same size as yours). He has a cyclone separator in the shop that returns air back into the space, at lower temp of course, but that really helps.
His big problem was on days when they ran the spray booth. That apparatus will pull 10,000 cfm of direct outside air straight into the shop. A real problem on days when it's less than 20* outside.
The 3 170's will temper the incoming air up about 45* above outdoor ambient so when gets below 10* outdoors he has to wait for a warmer day or he gets finish problems.

We put the same setup in a wood furniture factory (only larger) several years ago and fired it with a 500,000 natural gas boiler. Worked great.
That company got a price from me for an 8,000 sq ft addition and wanted to go with tube heaters. I told them no way because it was a recipe for disaster and priced them the same setup as the first job. Fan coils, big boiler and totally enclosed motors.

Long story short, they found some hack to install tube heaters cheap for them and the place burned to the ground within 8 months of completing the new addition. Tube heaters caught fire from accumulated dust.
Moral.....don't do tube heaters no matter what anyone tells you.

Think radiant walls and ceiling. It's work to install. But it works if you don't or can't go forced air.
Any way you slice it you are looking at a giant load there and you really want to think hard about the amount of wood you are going to be handling every day and processing every year. Basically you are going to hire another man to do it.

 

[phaywood]

Thanks for the insight. My DC system is connected to table saws, jointers, and planers. I am looking into some CNC machinery so the DC will be running most of the day when that is installed.

Right now, I'm leaning towards radiant in the ceiling because it will be less affected by the DC. Has anyone ever used Fin-Tube type radiators? I'm wondering if I could mount these higher up on the wall. That too would be a nice type of heat because it's heating the objects, not the air. Thanks heaterman - I hadn't considered the dust on the infrared tube heaters. I could see the dust being a major fire hazard! I'm also installing a finishing room and I'll probably put hydronic under a tile floor in there.

I know I'll be going through a lot of wood, but it's free. Hopefully I can find a boiler with a HUGE firebox so I'm not constantly refilling it.

Thanks again.

 

[heaterman]

Fin tube on the ceiling is not going to do it for you. That's convective heat and you'll wind up with the ceiling at about 130* and no heat where you work.

A radiant ceiling uses the same strategy as a radiant floor, in other words true "radiant" heat. Not convective air flow. It will heat your floor, all the machinery and you........from the ceiling.
The nice part is there is virtually no limit on how high you can drive the ceiling temp wise, unlike a radiant floor.

here's some reading material.
(broken link removed to http://www.uponor-usa.com/~/media/Extranet/Files/CDAM/CDAM_Manual_7thEd_0711_Ch9.aspx?sc_lang=en&version=072920111126)

Do the math on the wood at 21,000,000 btu's per cord and an efficiency of 70% (good gasification wood boiler, not outdoor)
That leaves you with a cord yielding about 15,000,000 btu's.net

In the shop we did, his heat load with the spray booth running was nearly an even million btu's if he wanted to maintain 70* in the shop with an outdoor of 10*..

That means a full cord would only run the place (under those conditions) for 2-8 hour days.
If you're going to be running a heating load of anywhere near that, you really need to factor in the labor for wood.It's a huge amount of work.

Over the years we installed a couple high load systems like that using excellent wood fired equipment. Neither of them are still using wood. It seriously amounted to a full time job for one man when all was said and done.

 

[flyingcow]

Damn phone..................

 

[phaywood]

So I ran a (rough) heat loss calculation and it appears that my main machine room requires about 200,000BTU/hr. Obviously the rest of the shop will require more but I'm mainly concerned about the machine room. Now I'm wondering if I'd be better off just running a wood burning furnace (no boiler) and ducting the air into the shop. If I filter my Dust Collection system so I'm not venting outside, then maybe forced air is the best option. It would certainly take much less installation work than a hydronic system...

I also realized that I could supplement with my existing propane heater on the coldest days and when I won't be in the shop. I don't want the hydronic lines to freeze if I'm on vacation.

Any thoughts on this?

 

[heaterman]

If you're thinking of forced air in an industrial sized unit get in touch with these guys.
You may tell them I sent you their direction.

http://www.biomasscombustion.com/