HobbyKing.com New Products Flash Sale
 
Thread Tools
Old Jan 14, 2010, 02:15 PM
Bob Minchin
Guest
n/a Posts
Re: Heating a workshop/garage

Donwill wrote:

> David Littlewood wrote:

>> In article <7r82crF173U1@mid.individual.net>, Donwill
>> <Donwill.seesig@invalid.invalid> writes

>>> Peter Parry wrote:
>>>> On Wed, 13 Jan 2010 10:48:38 +0000, Donwill
>>>> <Donwill.seesig@invalid.invalid> wrote:
>>>>
>>>>
>>>>> To minimise the risk of condensation on machines the temperature
>>>>> should be kept reasonably constant but that's expensive if you heat
>>>>> to a comfortable working temperature.
>>>>>
>>>>
>>>> If you are contemplating electric heating then start by installing one
>>>> or more dehumidifiers. Firstly they (obviously) dry the air but
>>>> secondly they recover the latent heat of evaporation so are slightly
>>>> more efficient than a 100% efficient radiant heater (you get more heat
>>>> out than electric energy equivalent put in).
>>>>
>>>> Another alternative which is much cheaper to run than resistive
>>>> heating is an inverter split unit air conditioner. This is an air
>>>> source heat pump with air drying. DIY fit versions are available.
>>>> Look for the coefficient of performance figure. In heat pump mode
>>>> these types of systems typically have a coefficient of performance
>>>> (CoP) of about 3. This means that a 3 KW air conditioner uses about 1
>>>> KW of power. Conversely a heat pump provides about 3 KW of heat while
>>>> using about 1 KW of power.
>>>>
>>>>
>>>>
>>> That sounds like the way to go, having done a quick search LG and
>>> Toshiba seem to be eminent in the field, do you have any experience
>>> with them that you can share? To keep the humidity down AND heat the
>>> wksp cheaply seems to be great. :-)
>>> Generally speaking, the air passing through the unit needs to be
>>> cooled to remove moisture, how does the unit apply heat to warm it up
>>> to working temp, is this where the so called "split" system comes in?
>>> To cool and then heat the air in principle seems wasteful ?
>>> Any info gratefully received.
>>> Don

>>
>> Don,
>>
>> Warming the air automatically reduces its relative humidity, so it
>> does not need to be cooled first.
>>
>> David

> You need to reduce the dewpoint temp of the air below the temperature of
> the machines in the wksp.
> e.g air at 22degC and 60% RH, will condense out at the DP of approx
> 14degC. If you can reduce the RH of the air to say 48% then the DP will
> be reduced to approx 11degC so if the machines are above 11deg C then
> water will not condense out on them.
> Don

Hence the efficacy of heating the machines.

One undesirable result of heating the air intermittently is that the
warmer air will pick up any excess moisture and then deposit it on
surfaces -such as machines- that don't heat up so quickly.
Continuous space heating above the dewpoint is good but can hurt the
wallet somewhat.

Bob
Old Jan 14, 2010, 05:37 PM
Mike
Guest
n/a Posts
Re: Heating a workshop/garage

On Thu, 14 Jan 2010 13:29:54 +0100, Dirk <df.ganzinga@jezusmail.com>
wrote:


>Recently extended the shed, used 70mmm aerated concrete blocks to make
>inner walls and floor heating. Now experimenting with Mother Earth's
>Waste Oil Heater. Made it from old 12 kg propane bottles. Google for
>the plans. Works fine with wood and lamp oil, but not - yet - on
>discarded frying oil as planned. It does not seem to get hot enough to
>ignite.


If it's using any combustion air from inside the workshop then such an
approach is guaranteed to promote massive swings in humidity resulting
in huge condensation problems.

Run them 24 hours a day round the clock with the door open to the
outside and they *might* be ok. But no one wants a workshop that hot
or draughty and that's the reason wood fired stoves, gas burning hot
air blowers or paraffin heaters are a pile of poo for a workshop.


--
Old Jan 14, 2010, 06:00 PM
Charles Lamont
Guest
n/a Posts
Re: Heating a workshop/garage

Mike wrote:


> If it's using any combustion air from inside the workshop then such an
> approach is guaranteed to promote massive swings in humidity resulting
> in huge condensation problems.


> ... that's the reason wood fired stoves, gas burning hot
> air blowers or paraffin heaters are a pile of poo for a workshop.


Surely it is not drawing combustion air from the shop but exhausting
combustion products containing water into it that is the problem. I
don't see why a stove, having an external flue outlet, would be a problem.

--
Charles Lamont
Old Jan 14, 2010, 06:06 PM
Dirk
Guest
n/a Posts
Re: Heating a workshop/garage

Mike had uiteengezet :

> On Thu, 14 Jan 2010 13:29:54 +0100, Dirk <df.ganzinga@jezusmail.com>
> wrote:
>

>> Recently extended the shed, used 70mmm aerated concrete blocks to make
>> inner walls and floor heating. Now experimenting with Mother Earth's
>> Waste Oil Heater. Made it from old 12 kg propane bottles. Google for
>> the plans. Works fine with wood and lamp oil, but not - yet - on
>> discarded frying oil as planned. It does not seem to get hot enough to
>> ignite.

>
> If it's using any combustion air from inside the workshop then such an
> approach is guaranteed to promote massive swings in humidity resulting
> in huge condensation problems.
>
> Run them 24 hours a day round the clock with the door open to the
> outside and they *might* be ok. But no one wants a workshop that hot
> or draughty and that's the reason wood fired stoves, gas burning hot
> air blowers or paraffin heaters are a pile of poo for a workshop.


Right! Exterior air intake will be added later on.
Old Jan 14, 2010, 06:20 PM
Tony Jeffree
Guest
n/a Posts
Re: Heating a workshop/garage

On Thu, 14 Jan 2010 22:37:10 +0000, Mike <nospam@nospam.com> wrote:


> that's the reason wood fired stoves, gas burning hot
>air blowers or paraffin heaters are a pile of poo for a workshop


The reason gas powered blowers and paraffin heaters (or free standing
gas heaters for that matter) are a problem is that they vent their
exhaust gases into the room - including water vapor at the rate of
about a liter of water per liter of paraffin or liquid gas burnt. An
enclosed wood burning stove with a flue venting its exhaust to the
outside isn't an issue. That is exactly what JS uses to heat his
workshop & he doesn't have a rust problem.

Regards,
Tony
Old Jan 14, 2010, 06:31 PM
Mike
Guest
n/a Posts
Re: Heating a workshop/garage

On Thu, 14 Jan 2010 23:00:37 +0000, Charles Lamont
<charles@gateho.gotadsl.co.uk> wrote:


>Mike wrote:
>

>> If it's using any combustion air from inside the workshop then such an
>> approach is guaranteed to promote massive swings in humidity resulting
>> in huge condensation problems.

>

>> ... that's the reason wood fired stoves, gas burning hot
>> air blowers or paraffin heaters are a pile of poo for a workshop.

>
>Surely it is not drawing combustion air from the shop but exhausting
>combustion products containing water into it that is the problem. I
>don't see why a stove, having an external flue outlet, would be a problem.


It has to get air from *somewhere* and unless your workshop is of
infinite size it will be drawing that air from outside, either via a
dedicated properly sized vent or (more dangerously from a Carbon
Monoxide point of view) from around cracks in the
door/windows/framework. That air, being continually replaced as
combustion occurs, is usually very moisture laden (at least in the UK)
and will, when the stove is shut down, cool and eventually deposit all
the moisture held in that 'fresh air' over everything.

Of course if you can source external air, direct to the stove, and
exhaust air direct to outside, and only use the hot surfaces of the
stove to heat the workshop then you might, with unlimited supplies of
fuel, have a cheap source of heat. Think of it as similar to a room
sealed boiler hanging on the wall of the kitchen. It keeps the room
warm(ish) with the heat lost to the boiler casing but despite burning
lots of gas or oil it doesn't fundamentally alter the humidity levels
in the room.

Such an approach will IMHO never compare to the comfort and luxury of
background underfloor heating fed off the main central heating circuit
of the main property, nor will it compare to solar air heaters in
simplicity and zero carbon emissions.

--
Old Jan 14, 2010, 06:51 PM
Mike
Guest
n/a Posts
Re: Heating a workshop/garage

On Thu, 14 Jan 2010 23:20:07 +0000, Tony Jeffree <tony@jeffree.co.uk>
wrote:


>The reason gas powered blowers and paraffin heaters (or free standing
>gas heaters for that matter) are a problem is that they vent their
>exhaust gases into the room - including water vapor at the rate of
>about a liter of water per liter of paraffin or liquid gas burnt. An
>enclosed wood burning stove with a flue venting its exhaust to the
>outside isn't an issue. That is exactly what JS uses to heat his
>workshop & he doesn't have a rust problem.


It's not the combustion products, it's the fresh air draw especially
when you have intermittent use that is common in the amateur workshop.
Maybe with JS the extended length of burn with long days and the mass
of the machines helps to some extent but the humidity levels will
almost certainly go all over the place. A few years ago I measured
them over an extended period in a commercial joinery workshop that
occasionally had serious condensation problems unless they left the
workshop doors open. I rejected wood burning for my own workshop for
precisely that reason. I have access to huge amounts of free well
seasoned scrap wood but I'd *never* use it in any conventional
workshop stove.


--
Old Jan 14, 2010, 08:16 PM
Richard Shute
Guest
n/a Posts
Re: Heating a workshop/garage

On Thu, 14 Jan 2010 23:51:08 +0000, Mike <nospam@nospam.com> wrote:


>On Thu, 14 Jan 2010 23:20:07 +0000, Tony Jeffree <tony@jeffree.co.uk>
>wrote:
>

>>The reason gas powered blowers and paraffin heaters (or free standing
>>gas heaters for that matter) are a problem is that they vent their
>>exhaust gases into the room - including water vapor at the rate of
>>about a liter of water per liter of paraffin or liquid gas burnt. An
>>enclosed wood burning stove with a flue venting its exhaust to the
>>outside isn't an issue. That is exactly what JS uses to heat his
>>workshop & he doesn't have a rust problem.

>
>It's not the combustion products,

A water output of roughly one for one is pretty significant in my
view.

it's the fresh air draw especially

>when you have intermittent use that is common in the amateur workshop.

<....>
It is certainly the case that, especially during winter, the air
inside a house contains vastly more moisture than outside air,
although it is usually at a lower RH.

Is it your conjecture that this is not the case in a workshop
(assuming a similar 'room' temperature)? Maybe because there are few
if any moisture generators in the workshop such as people, dogs
cooking etc.?

If not then any air drawn in to the workshop to feed the fire would
acually reduce the water content not increase it since incomming air
contains very little water even though the RH is high outside.


Richard

--- news://freenews.netfront.net/ - complaints: news@netfront.net ---
Old Jan 15, 2010, 07:25 AM
Tony Jeffree
Guest
n/a Posts
Re: Heating a workshop/garage

On Thu, 14 Jan 2010 23:51:08 +0000, Mike <nospam@nospam.com> wrote:


>It's not the combustion products, it's the fresh air draw especially
>when you have intermittent use that is common in the amateur workshop.
>Maybe with JS the extended length of burn with long days and the mass
>of the machines helps to some extent but the humidity levels will
>almost certainly go all over the place. A few years ago I measured
>them over an extended period in a commercial joinery workshop that
>occasionally had serious condensation problems unless they left the
>workshop doors open. I rejected wood burning for my own workshop for
>precisely that reason. I have access to huge amounts of free well
>seasoned scrap wood but I'd *never* use it in any conventional
>workshop stove.


It would be worth doing the numbers on this, but my guess is that the
moisture brought in from the outside is a minor problem compared with
the moisture exhaled and perspired by the engineer(s) in the workshop.

You could fix that by wearing a fully seald CBW suit & breathing kit I
guess ;-)

Regards,
Tony
Old Jan 15, 2010, 11:13 AM
Harry Bloomfield
Guest
n/a Posts
Re: Heating a workshop/garage

Charles Lamont explained on 14/01/2010 :

> Surely it is not drawing combustion air from the shop but exhausting
> combustion products containing water into it that is the problem. I don't see
> why a stove, having an external flue outlet, would be a problem.


Nor I, apart from the fact that it will be drawing its combustion air
in from outside, through what ever ventilation it can find. Perhaps
better to organise a more direct method of air entry, close to the
burner?

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk
Old Jan 15, 2010, 11:16 AM
Harry Bloomfield
Guest
n/a Posts
Re: Heating a workshop/garage

Dirk explained :

> Recently extended the shed, used 70mmm aerated concrete blocks to make inner
> walls and floor heating. Now experimenting with Mother Earth's Waste Oil
> Heater. Made it from old 12 kg propane bottles. Google for the plans. Works
> fine with wood and lamp oil, but not - yet - on discarded frying oil as
> planned. It does not seem to get hot enough to ignite.
> Best regards, Dirk


I found the US plans to make one from an old steel HW tank, but nothing
for reusing old 12Kg gas bottles - which was what I was planning to
have a go at - have you a URL?

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk
Old Jan 15, 2010, 11:41 AM
Dirk
Guest
n/a Posts
Re: Heating a workshop/garage

Het is zņ dat Harry Bloomfield formuleerde :

> Dirk explained :

>> Recently extended the shed, used 70mmm aerated concrete blocks to make
>> inner walls and floor heating. Now experimenting with Mother Earth's Waste
>> Oil Heater. Made it from old 12 kg propane bottles. Google for the plans.
>> Works fine with wood and lamp oil, but not - yet - on discarded frying oil
>> as planned. It does not seem to get hot enough to ignite.
>> Best regards, Dirk

>
> I found the US plans to make one from an old steel HW tank, but nothing for
> reusing old 12Kg gas bottles - which was what I was planning to have a go at
> - have you a URL?


Hi Harry, correct. I used whatever was at hand, so bottles. Mine looks
much like Roger Sanders' heater, type MEN(ew). The original is the ME
type. MEN is linked on that page, also some forced-air ones.
Old Jan 15, 2010, 12:45 PM
Harry Bloomfield
Guest
n/a Posts
Re: Heating a workshop/garage

Dirk submitted this idea :

> Het is zņ dat Harry Bloomfield formuleerde :

>> Dirk explained :

>>> Recently extended the shed, used 70mmm aerated concrete blocks to make
>>> inner walls and floor heating. Now experimenting with Mother Earth's Waste
>>> Oil Heater. Made it from old 12 kg propane bottles. Google for the plans.
>>> Works fine with wood and lamp oil, but not - yet - on discarded frying oil
>>> as planned. It does not seem to get hot enough to ignite.
>>> Best regards, Dirk

>>
>> I found the US plans to make one from an old steel HW tank, but nothing for
>> reusing old 12Kg gas bottles - which was what I was planning to have a go
>> at - have you a URL?

>
> Hi Harry, correct. I used whatever was at hand, so bottles. Mine looks much
> like Roger Sanders' heater, type MEN(ew). The original is the ME type. MEN is
> linked on that page, also some forced-air ones.


What did you do, weld one 12kg on top of another? You can get much
larger (taller) red propane bottles. I was thinking of a single 12kg
bottle, I just need a small heater to take the chill off.

Are UK garages likely to give the old oil away, like in the US?

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk
Old Jan 15, 2010, 03:37 PM
Dirk
Guest
n/a Posts
Re: Heating a workshop/garage

Harry Bloomfield schreef op 15-1-2010 :

> Dirk submitted this idea :

>> Het is zņ dat Harry Bloomfield formuleerde :

>>> Dirk explained :
>>>> Recently extended the shed, used 70mmm aerated concrete blocks to make
>>>> inner walls and floor heating. Now experimenting with Mother Earth's
>>>> Waste Oil Heater. Made it from old 12 kg propane bottles. Google for the
>>>> plans. Works fine with wood and lamp oil, but not - yet - on discarded
>>>> frying oil as planned. It does not seem to get hot enough to ignite.
>>>> Best regards, Dirk
>>>
>>> I found the US plans to make one from an old steel HW tank, but nothing
>>> for reusing old 12Kg gas bottles - which was what I was planning to have a
>>> go at - have you a URL?

>>
>> Hi Harry, correct. I used whatever was at hand, so bottles. Mine looks much
>> like Roger Sanders' heater, type MEN(ew). The original is the ME type. MEN
>> is linked on that page, also some forced-air ones.

>
> What did you do, weld one 12kg on top of another? You can get much larger
> (taller) red propane bottles. I was thinking of a single 12kg bottle, I just
> need a small heater to take the chill off.
>
> Are UK garages likely to give the old oil away, like in the US?


Yes Harry, I cut off both tops to get rid of the valve sections. Did
not weld them together yet to get inside for changes, etc. Made a flew
and an intake of 100mm both. Contacted Roger Sanders to get data on
diameters, relations. I assumed a ratio between flew/intake and
circomference of container. Roger says they seem more or less absulute.
I am located in the Netherlands. Best regards, Dirk
Old Jan 15, 2010, 04:26 PM
Harry Bloomfield
Guest
n/a Posts
Re: Heating a workshop/garage

After serious thinking Dirk wrote :

> Harry Bloomfield schreef op 15-1-2010 :

>> Dirk submitted this idea :

>>> Het is zņ dat Harry Bloomfield formuleerde :
>>>> Dirk explained :
>>>>> Recently extended the shed, used 70mmm aerated concrete blocks to make
>>>>> inner walls and floor heating. Now experimenting with Mother Earth's
>>>>> Waste Oil Heater. Made it from old 12 kg propane bottles. Google for the
>>>>> plans. Works fine with wood and lamp oil, but not - yet - on discarded
>>>>> frying oil as planned. It does not seem to get hot enough to ignite.
>>>>> Best regards, Dirk
>>>>
>>>> I found the US plans to make one from an old steel HW tank, but nothing
>>>> for reusing old 12Kg gas bottles - which was what I was planning to have
>>>> a go at - have you a URL?
>>>
>>> Hi Harry, correct. I used whatever was at hand, so bottles. Mine looks
>>> much like Roger Sanders' heater, type MEN(ew). The original is the ME
>>> type. MEN is linked on that page, also some forced-air ones.

>>
>> What did you do, weld one 12kg on top of another? You can get much larger
>> (taller) red propane bottles. I was thinking of a single 12kg bottle, I
>> just need a small heater to take the chill off.
>>
>> Are UK garages likely to give the old oil away, like in the US?

>
> Yes Harry, I cut off both tops to get rid of the valve sections. Did not weld
> them together yet to get inside for changes, etc. Made a flew and an intake
> of 100mm both. Contacted Roger Sanders to get data on diameters, relations. I
> assumed a ratio between flew/intake and circomference of container. Roger
> says they seem more or less absulute. I am located in the Netherlands. Best
> regards, Dirk


Thanks..

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk
 


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Garage/workshop temprature control... kepople Electric Plane Talk 13 Apr 30, 2004 12:51 PM