Heating In The Winter....

I use a 30K BTU ventless propane heater from TSC. My shop is 32 x 40, in the winter I run a set of tarps down the middle so the metal side is 32 x 20. I have 2 ceiling fans that run 24/7/365, no rust on anything as it keep the air moving. Cast iron/steel gets sprayed down with LPS 1 on occasion to help. The heater gets popped on when I need it; it's fed from a 100 lb. propane tank. It'll raise the shop temp around 30 F in an hour.

Bruce
 
Hello Armourer,

My shop is my attached 2-car garage, about 20'x20'.

I agree with RJ's statement above:
Insulation is probably the most economical improvement.

My goal all winter is to keep the shop from freezing. Although I do have antifreeze in the TIG cooler, there's the usual assortment of glues, paints, etc.
For me I try to minimize the heat loss to outside and allow some heat escape from the house to the shop. Note I am NOT talking about venting the shop to the house.....even if you can't get a car in there, there are still other fumes you don't want in the house. I just mean not insulating that wall too well.

With the better insulation and the heat "leakage" from the house I can keep the entire shop above freezing with one small baseboard heater.
For working out these, I use one of those orange cube electric construction heaters.

I too have thought about some sort of stove out there, but the insurances b4st4rds rule that out.
My Dad finally cancelled his house insurance for this very reason.

-brino
 
Bob, you would think so. But I have not noticed a problem in my shop, and I am not sure why. My shop is not very tight and the roof is vented at the peak and the roll up door has a pretty loose fit also. So I guess the venting is pretty good and that may be why I'm not getting rust. I'm burning about 60 gal of propane a month mid winter.
Well, extra moisture is certainly being created by burning the propane. OTOH, the temperature is rising, which lowers the relative humidity. The moisture problem occurs when the moisture laden air cools and condenses. You apparently have enough ventilation for the moist air to escape before it condenses. I guess that works, but is is not very efficient. Sometimes simple and effective wins over efficient...
 
Burning a gallon of LP produces almost a gallon of water vapor (along with about 14 lbs. of CO2). If not vented, water vapor will condense on the coldest surfaces which will be your outside walls in an uninsulated or poorly insulated shop.

I run a dehumidifier 24/7 in my basement shop during the summer and pull out about 2 gallons of water a day. This, in conjunction with the central A/C, keeps the house and shop at around 50% RH and I do not have a significant rust problem. If I let the humidity creep up, I start to see rusting.

IMO, if using an unvented burner in an enclosed environment, proper consideration must be given to venting and air exchange. The problem is that bringing fresh air which may be -20ºF in the winter is counter intuitive. Maybe it is ingrained from childhood when my mother scolded me "Shut that door. We're not heating the outside!".

One solution would be to make a heat exchanger for the exchange air. Some years ago, I designed a heat exchanger where the outgoing warm air would heat the incoming air, capturing some of the escaping BTU's. It never got built because the need disappeared ( I heat with wood and my exhaust air goes up the chimney).

Here is a concept sketch. The sketch is essentially a floor plan withe the height suitably chosen for the volume of air required. The walls between the intake and exhaust chambers would be made from a thermally conductive material while the flow reversing baffles can be any suitable material. As intake air flows through, it will be progressively warmed by the heat removed from the exhaust air. Ideally, the intake air will be almost at room temperature as it enters the room while the exhaust air will have lost almost all of its excess heat value.
Heat Exchanger.JPG
 
RJ will there be a condensate collector or pan or something. It seems to me that when the warm moist air gets cooled there will be some sort of condensate some where.

David
 
RJ will there be a condensate collector or pan or something. It seems to me that when the warm moist air gets cooled there will be some sort of condensate some where.

David
David, Good point! I don't humidify my air in the winter so the RH in our house is quite low. However, is using a heater which exhausts into the room, there will be a lot more moisture. Condensate could be dealt with but if it starts to freeze up, it could end up blocking the air flow. As I said, it was a concept. It looks like it needs some additional thought to make a functional system.

I have recently seen commercial heat exchangers used to deal with radon gas buildup. Apparently, they deal with frost buildup by use of a damper which cuts off the cold air and routes warm air through the system to defrost it. When defrosted, the damper reverts to normal operation.

Here is a link to an article on the operation:
http://www.popularmechanics.com/home/interior-projects/how-to/a149/1275121/

Here are some links to commercial units.
http://www.lennox.com/products/indoor-air-quality/ventilation/hrv
http://www.broan.com/fresh-air-systems
 
Burning a gallon of LP produces almost a gallon of water vapor (along with about 14 lbs. of CO2). If not vented, water vapor will condense on the coldest surfaces which will be your outside walls in an uninsulated or poorly insulated shop.

I run a dehumidifier 24/7 in my basement shop during the summer and pull out about 2 gallons of water a day. This, in conjunction with the central A/C, keeps the house and shop at around 50% RH and I do not have a significant rust problem. If I let the humidity creep up, I start to see rusting.

IMO, if using an unvented burner in an enclosed environment, proper consideration must be given to venting and air exchange. The problem is that bringing fresh air which may be -20ºF in the winter is counter intuitive. Maybe it is ingrained from childhood when my mother scolded me "Shut that door. We're not heating the outside!".

One solution would be to make a heat exchanger for the exchange air. Some years ago, I designed a heat exchanger where the outgoing warm air would heat the incoming air, capturing some of the escaping BTU's. It never got built because the need disappeared ( I heat with wood and my exhaust air goes up the chimney).

Here is a concept sketch. The sketch is essentially a floor plan withe the height suitably chosen for the volume of air required. The walls between the intake and exhaust chambers would be made from a thermally conductive material while the flow reversing baffles can be any suitable material. As intake air flows through, it will be progressively warmed by the heat removed from the exhaust air. Ideally, the intake air will be almost at room temperature as it enters the room while the exhaust air will have lost almost all of its excess heat value.
View attachment 135242
Commercial heat exchangers for changing out room air use Coroplast, stacked in alternate layers pointing opposite directions. Cheap, efficient, and easy.
 
I want to see that 100% efficient heater. I suspect that Mr Newton's second law might disagree.

The problem with salamanders is noise and the combustion by-products.

In my case, diesels fuel would have to rise to about $5/gallon for it to be cheaper for me to heat with propane as we do not have natural gas. Were I to hike to the fuel supply, I could get off-road diesel even less expensive.

I use an old home fuel oil furnace to heat my shop. It sucks down the fuel-which is typically about 20-30% used engine oil-but is quiet and warm. It has a crack in the heat exchanger, but it has to be better than the salamander I was using for so long.

While it may take up floor space and be expensive, it is safe and you can buy fuel for it in small quantities nearly anywhere and as mine is a forced draft, the venting requirements are minimal.
 
Please be careful about Carbon Monoxide toxicity.
It is a real thing.
Chronic low exposures, while not acutely lethal, are linked with symptoms similar to dementia/Alzheimers.
If someone wants the research I go looking for the documents.

Daryl
MN
 
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