Heat for small shop

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Hello I'm building a new but small shop, it will be 8' X 10' how ever living in the north east it will get cold up here, it will be insulated, tyvec wrapped and sided, have ac for the summer, but need heat for the winter, I saw and like the "Hot Dog" heaters that hang from the ceiling and run on propane, any input will be gladly welcomed.
Cheers, Thomas Cleveland
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THOMAS CLEVELAND, wrote the following at or about 6/7/2007 1:01 PM:

Unless it's a sealed system, I'd be leery of a gas unit in a workshop.
I installed one of these (a Dayton Electric G73 electric ceiling heater) in my 24'x16' shop two years ago and have never regretted the decision for a second.
It keeps the well insulated shop above 45 degrees year around very economically and when I want to work out there in the dead of winter, brings the shop up to around 70 degrees in about 12-17 minutes. I ran a separate 30amp line for it (have a 100 amp panel in the garage/shop).
<http://www.dealtime.com/xPF-G73
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THOMAS CLEVELAND wrote:

I don't know what a "hot dog" heater is (by that name at least) but I'll echo Confused's concern -- gas is ok in a shop but should definitely be external draft model, not internal. Higher initial cost, but for a small area wouldn't be exorbitantly different and the peace of mind is priceless...
Only way I'd relent is if this is to be an "all-Neandertool" shop and no plan for finishing--in that case the dust and/or fumes generation could be minimal enough as to not be a major concern.
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living
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I may not be the same as the rest of you folks. OK, I'm not. But what I planned to do in my shop when I started 6 or 8 years ago is different than what I do today.
Make no inflexible choices, particularly where safety is concerned.
I started out with power tools, but I don't use them nearly as much as I used to. At least, it seems that way. Maybe it's just less dramatic than it once was.
Get a good, externally vented heater. This isn't an open construction site we're discussing here. Fumes accumulate.
Patriarch
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SNIP of good thoughts

Absolutely couldn't agree more. Even radiant heaters can generate a spark by igniting a small piece of sawdust thrown in the air that circulates close to the elements, and on the better ones that put out some real heat, I have seen little sparklets generated when heavy sanding appears.
It wouldn't take much for all manner of fumes to accumulate in a shop that small. No would it take much for noxious gasses to build up DEPENDING on the type of heater you get as the years go by and the machine becomes less efficient at burning its fuel.
Robert
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On Thu, 7 Jun 2007 14:01:08 -0400, snipped-for-privacy@webtv.net (THOMAS CLEVELAND) wrote:

I just use a "construction" heater hung from my ceiling- takes up little space and provides plenty of heat- especially if the shop is small and insulated.
Runs on 220, have had one for 8 years, no problems at all. Live in central BC so the heater gets plenty of use.
Mick
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mick wrote:

Hi Thomas. I used the smallest Hot Dog heater in my old 650 sq ft. shop. In your smaller shop, I think you would find it overwhelming. Lots of btu's, lots of air movement - too much of both in 80 sq. ft would be my guess.
Rick
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mick wrote:

I used the same type of heater in my 12 x 20 shed. I lived in the shed while I was building my house. Slept out there when temps. got down below -40 deg. Mild Manitoba winter night. :)
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THOMAS CLEVELAND wrote:

Never having been in the NE, it still seems to me that for a small "insulated, tyvec wrapped and sided" 8x10 shop like yours practically any small electric space heater would do the job.
Wayne
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THOMAS CLEVELAND wrote: | Hello | I'm building a new but small shop, it will be 8' X 10' how ever | living in the north east it will get cold up here, it will be | insulated, tyvec wrapped and sided, have ac for the summer, but | need heat for the winter, I saw and like the "Hot Dog" heaters that | hang from the ceiling and run on propane, any input will be gladly | welcomed.
You might find the link below if interest - a somewhat larger shop in my area that's solar heated.
-- Morris Dovey DeSoto Solar DeSoto, Iowa USA http://www.iedu.com/DeSoto/SC_Madison.html
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Morris Dovey, wrote the following at or about 6/7/2007 5:27 PM:

Morris, forgive me for asking if you've explained this previously but what's the square footage of that shop, the ceiling height and what do you consider to be a "comfortable daytime temperature" in the winter months for that particular application?
Also, that makeup heater looks to be just a tad bigger than the one I have. What is it, about a 7500 watt?
That is just such a great looking installation and shop area and to think, once installed and paid for, it's nearly maintenance free and starts paying back immediately.
Were I building/rebuilding my shop, we'd be talking for sure<g.
Great work!
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Unquestionably Confused wrote: | Morris Dovey, wrote the following at or about 6/7/2007 5:27 PM: || THOMAS CLEVELAND wrote: ||| Hello ||| I'm building a new but small shop, it will be 8' X 10' how ever ||| living in the north east it will get cold up here, it will be ||| insulated, tyvec wrapped and sided, have ac for the summer, but ||| need heat for the winter, I saw and like the "Hot Dog" heaters ||| that hang from the ceiling and run on propane, any input will be ||| gladly welcomed. || || You might find the link below of interest - a somewhat larger shop || in my area that's solar heated. | | Morris, forgive me for asking if you've explained this previously | but what's the square footage of that shop, the ceiling height and | what do you consider to be a "comfortable daytime temperature" in | the winter months for that particular application?
That shop is 30' x 40' - so floor space will be a bit less than 1200 sq ft. A comfortable daytime temperature is anything in excess of 72F. If there's a run of especially sunny days, the owner will probably need to open windows during the day to keep the temperature in the 70's.
| Also, that makeup heater looks to be just a tad bigger than the one | I have. What is it, about a 7500 watt?
I don't remember - I think he told me that it's a 20kBtu heater. Food for thought: in the solar context, his ceiling fan will be even more important than his unit heater.
| That is just such a great looking installation and shop area and to | think, once installed and paid for, it's nearly maintenance free and | starts paying back immediately. | | Were I building/rebuilding my shop, we'd be talking for sure<g>.
Always glad to do that - on the other hand, one of the purposes of that web page is to demonstrate the total absence of magic. On the third hand, there's more to the design than meets the eye. <g>
If you're inclined to go the DIY route, there're links on the DeSoto Solar home page that provide some essential "getting started" information. (Some of the info is specific to the USA, and I'd be pleased to be able to make the same information available for other parts of the world.)
| Great work!
Thanks. It's interesting to wrestle with the trade-offs to deliver a maximum of heat for a minimum of cost - in a panel intended to serve for the lifetime of the structure. These panels were the best I'd ever produced - but provided info leading to _three_ low-cost design improvements that'll make these inferior to all my future panels.
-- Morris Dovey DeSoto Solar DeSoto, Iowa USA http://www.iedu.com/DeSoto/SC_Madison.html
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Morris Dovey, wrote the following at or about 6/7/2007 9:20 PM:

Any idea how impressive that is to us dorks who are paying into the grid?<g> That's incredible, Morris. If you don't mind saying, what was the cost of those "Panels of Madison County."

That's close to what I use in my shop. I think the high output mode on the Dayton is 17.5kBTU
I can understand the necessity for the ceiling fan as we have cathedral ceilings in the kitchen and family room. Certainly helps to balance the heat from the wood stove out there.

It certainly does make a point. No magic, but the output is way more than what I ever would have guessed for those two panels in that sized structure.
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Unquestionably Confused wrote: | Morris Dovey, wrote the following at or about 6/7/2007 9:20 PM:
|| That shop is 30' x 40' - so floor space will be a bit less than || 1200 sq ft. A comfortable daytime temperature is anything in || excess of 72F. If there's a run of especially sunny days, the || owner will probably need to open windows during the day to keep || the temperature in the 70's. | | Any idea how impressive that is to us dorks who are paying into the | grid?<g> That's incredible, Morris. If you don't mind saying, | what was the cost of those "Panels of Madison County."
It's not a "Bad Thing" to pay into the grid - it's only bad to pay in more than is needful. Solar energy isn't a panacea, but in some applications it does offer solid economic advantage.
I don't mind saying - but I say it at http://www.iedu.com/DeSoto/sc_prices.html so no one finds an old price in the archive and gets PO'd because I ask 'em to write a check for more than what they'd found.
The sun does deliver an impressive amount of energy to our little planet. I've knocked myself out to produce a design to capture everything from low-frequency EM through UV, and it seems to pay off (most notably in the IR range). If you haven't seen the plot of solar energy distribution by wavelength, you might find http://www.iedu.com/DeSoto/Absorber.html interesting.
|| I don't remember - I think he told me that it's a 20kBtu heater. || Food for thought: in the solar context, his ceiling fan will be || even more important than his unit heater. | | That's close to what I use in my shop. I think the high output | mode on the Dayton is 17.5kBTU | | I can understand the necessity for the ceiling fan as we have | cathedral ceilings in the kitchen and family room. Certainly helps | to balance the heat from the wood stove out there.
In this shop, the insulated 6" concrete slab acts as a big thermal "flywheel". Since warmed air "wants" to stay up near the ceiling, the fan is necessary to shoot it down to warm the floor. When the sun sets and the solar panel shuts down, the heat stored in the floor radiates as IR to extend the daily comfort period and prevent the shop temperature from dropping anywhere near the freezing range overnight.
|| Always glad to do that - on the other hand, one of the purposes of || that web page is to demonstrate the total absence of magic. On the || third hand, there's more to the design than meets the eye. <g> | | It certainly does make a point. No magic, but the output is way | more than what I ever would have guessed for those two panels in | that sized structure.
The structure is well-sealed and well-insulated, which is important regardless of heating system. If you stand a full arm's length away from these panels at noon on the winter solstice, these totally passive panels will blow your hair back - if you have hair <vbg>
It's important to panel efficiency to get the heat out of the panel as quickly as possible. By designing to maximimize capture bandwidth and to maximize the volume of air flowing through the panel, the panel operates at a lower temperature and delivers more heat. Operating the panel at a lower temperature reduces the black body (IR) radiation back through the glazing, and lowers conductive losses through the panel body. It's a balancing act, but as you home in on the balance point, panel performance does seem to peak spectacularly.
-- Morris Dovey DeSoto Solar DeSoto, Iowa USA http://www.iedu.com/DeSoto /
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Morris Dovey, wrote the following at or about 6/8/2007 6:07 PM:>

Sorry about that, found the price list after the question went out. Damn! ~$3200 for a unit to heat that place. Let's see now... Gotta be what? >$2000 for a decent FANG unit, ductwork and install and you get to keep paying and paying to keep it fueled and running vs what solar offers. Damn that's a hard one - not!<g>

Again, I guess I'm somewhat surprised that the concrete (insulated or not) comes into play that much. Would expect it, I guess, from basking in the direct sunlight behind a wall of windows, etc. but not so much with the air above circulating over it.

Yeah, I still have enough to blow around with a convertible and probably with one of your panels as well. What really blows me away though is your system. Thanks for sharing your knowledge.

Okay, that explains why the high efficiency panels are "more better" though they are operating at 140 degrees vs the discontinued economy panels that were running at 160 degrees.
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Unquestionably Confused wrote: | Morris Dovey, wrote the following at or about 6/8/2007 6:07 PM:>
|| In this shop, the insulated 6" concrete slab acts as a big thermal || "flywheel". Since warmed air "wants" to stay up near the ceiling, || the fan is necessary to shoot it down to warm the floor. When the || sun sets and the solar panel shuts down, the heat stored in the || floor radiates as IR to extend the daily comfort period and || prevent the shop temperature from dropping anywhere near the || freezing range overnight. | | Again, I guess I'm somewhat surprised that the concrete (insulated | or not) comes into play that much. Would expect it, I guess, from | basking in the direct sunlight behind a wall of windows, etc. but | not so much with the air above circulating over it.
Normally (without the fan) the slab would not play such an important role. The ceiling fan provides a whole collection of benefits, and it's difficult to say that any one of them is more important than the others.
By pushing the warm air away from the ceiling, it helps to reduce conductive losses through the ceiling.
By mixing the warm air with the cooler air below it reduces stratification and evens out the heat distribution throughout the shop to make the whole more comfortable.
The continuous flow of warm air on the insulated slab warms raises its temperature (stores energy in it) so that the it will begin giving up its heat to the air as soon as the air temperature drops below that of the slab. If the slab were left cold, it would still take some energy from the air that touched it, but it would warm less and might continue absorbing heat well beyond the point where the air felt chilly.
|| It's important to panel efficiency to get the heat out of the || panel as quickly as possible. By designing to maximimize capture || bandwidth and to maximize the volume of air flowing through the || panel, the panel operates at a lower temperature and delivers more || heat. Operating the panel at a lower temperature reduces the black || body (IR) radiation back through the glazing, and lowers || conductive losses through the panel body. It's a balancing act, || but as you home in on the balance point, panel performance does || seem to peak spectacularly. | | Okay, that explains why the high efficiency panels are "more better" | though they are operating at 140 degrees vs the discontinued economy | panels that were running at 160 degrees.
Exactly! The concept you've grasped is of the utmost importance - that heat (energy) and temperature are _not_ synonyms.
My current aim is to lower that 140F to 120F for a 6'-tall panel without major cost increase. The Madison County installation won't quite make it but I'm getting closer with every design iteration. Interestingly, I'm not sure that achieving that goal will necessarily produce a more efficient /system/.
-- Morris Dovey DeSoto Solar DeSoto, Iowa USA http://www.iedu.com/DeSoto/SC_Madison.html
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Morris Dovey wrote:

How about a hybrid system? Would not adding, say, a low-cost (operation) axial/muffin fan with a rheostat allow you to tweak the internal temperature?
In your scheme of things that'd be cheating, I know, but... I'm just thinking aloud here. Even from a testing/design aspect you'd at least be able to see if the 120F would be more efficient, no?
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Unquestionably Confused wrote: | Morris Dovey wrote:
|| My current aim is to lower that 140F to 120F for a 6'-tall panel || without major cost increase. The Madison County installation won't || quite make it but I'm getting closer with every design iteration. || Interestingly, I'm not sure that achieving that goal will || necessarily produce a more efficient /system/. | | How about a hybrid system? Would not adding, say, a low-cost | (operation) axial/muffin fan with a rheostat allow you to tweak the | internal temperature? | | In your scheme of things that'd be cheating, I know, but... I'm | just thinking aloud here. Even from a testing/design aspect you'd | at least be able to see if the 120F would be more efficient, no?
I don't consider fans cheating - but insist that they not actually /impede/ operation of the panel.
At this point, the best of the axial/muffin fans (I have a small collection of not-so-cheap fans of a variety of types brought in by well-meaning friends) and all except the very largest (1/2 HP and up) act more as obstructions than enhancements to the airflow - even when running full-bore.
Although it's not an issue involving "cheating", I really do prefer the absolutely silent operation of the purely convectional operation.
I can boost the natural convection (lower temperature) by "streamlining" the interior plenums - rounding all the interior angles in the plenums, providing still smoother internal surfaces, etc. - but from where the design is today, all of these represent significant increases in labor and/or material costs.
The system question is: "What is the optimal discharge temperature that provides a comfortable environment for humans yet allows maximum _coincidental_ heat storage in a typical installation?"
The question contains a hidden twist in that excess heat can be discarded without impacting operational costs in any way - with an additional consideration that the discard mechanism can be used to control humidity.
It's the "typical installation" that's the unknown here. I don't need fans - what I really need is a variety of solar-heatable /structures/ to test. :-)
-- Morris Dovey DeSoto Solar DeSoto, Iowa USA http://www.iedu.com/DeSoto /
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My shop is 12 x 24 metal siding and roof and no insulation, located in southern MN.
When outside temperature is below 35 degrees I abandon it and do other things.
But warmer than that, I bundle up good (insulated pants, multiple jacket layers, and stocking cap) and go out. I have a small propane radiant heater (the round type). I hung 2 250 watt heat lamps over the bench, and two over the lathe.
(By the way, I tested the heater by blowing a handful of sawdust into it when it was running. Just a mini 4th of July as dust grains flared into sparks).
I've been amazed how much I can do in that environment, without my hands getting TOO cold. Of course any gluing, or finishing has to be moved into a heated location, as well as anything that has water.
Probably doesn't fit your situation.
Old Guy Luxuriating in warmth these days.

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With a shop that is a mere 8' x 10' then, unless you are a person who would prefer to work wood on a beach in the Bahamas, you'll do just fine with a quartz radiant heater as you will not be moving around very much in such a relatively confined space. The quartz heater is grand for heating a static area of the workbench where hand/power tool work is done. That, and a quilted shirt on the coldest of days in winter, will serve you well, IMO, as any sort of open flame is just asking for trouble. A blast of human/compressed air on the heater to dispel any accumulated dust or whatever is all that is needed prior to starting the heater (and then only if you have a really dusty shop).
J.
(working in one half of a two-car garage in NY for nearly 15 years)
THOMAS CLEVELAND wrote:

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