Workshop Heating

[Jo]

Now that the winter is here heating the workshop is becoming critical for normal production to continue. I gave up heating by gas fires in the 90's because they make masses of moisture and rust the machines . Since then I have been using electric heaters, first storage heaters which worked out about ?1.50 a day, then I moved over to convection heaters.

The storage heaters were great they heated up the infrastructure very nicely but cost a lot. I then found that the convection heaters worked out less expensive, they were not as good as the storage heaters but if you forgot to turn the storage heaters on you find yourself using the convection heaters any way.

As of last year workshop heating had a its next major change: having installed solar panels the challenge now is to use every free watt of power they generate. This is great and on a sunny mid winter day it is generating an average of 2KW from 10am to 3pm . But I understand that I could increase my heat per watt output by a factor of four by using heat exchangers..... Does any one have any experience of these?

Jo

 

[dvbydt]

Jo, as part of a deal when I sold my shaper, I got a Mitsubishi air conditioning unit. It had been properly capped when removed, so there was still gas in it. Rigged it up and as it was summer, tried it as a cooler - absolute magic! Called the local aircon guy and he topped up the gas pressure and it was good to go.

Now the point is that it is also a very efficient blower heater. For every kilowatt of electricity used it can produce the equivalent of up to 3 kilowatts of heat output even when it is cold outside. As a bonus, it reduces the humidity at the same time. If you can "acquire" one cheaply enough, it will make working in the shop much more comfortable. My shop is 200 sq.ft. by 8ft. high.

Ian

[RMO]

Jo,

While this may not work for you, I was able to install floor heating when I built my shop.  I use a water heater and a pump to circulate warm water through the floor.  Keeps my feet warm and is very stable.  When we get the house built next to the shop we will use a more efficient boiler system to heat both the shop and the house.

[grayone]

When we get the house built next to the shop we will use a more efficient boiler system to heat both the shop and the house.

So right now you live in the shop 

[steamer]

".....For every kilowatt of electricity used it can produce the equivalent of up to 3 kilowatts of heat output even when it is cold outside..."

Are you Sure about that Ian?

Jo , My house is heated with natural gas.   I had a gas line to the clothes dryer, but had an Electric dryer, so I had a natural gas direct vent gas heater installed in the shop.   It draws all combustion air directly from outside and relys on air circulation over the outside of the combustion chamber to heat the air in the shop.   It works wonderfully, and in my neck of the woods...you need a good heater!

I had it installed such that it complies with code to allow a automobile to be stored in the shop if desired....though that's never going to happen while I own the house!

A window air conditioner takes care of the summer season
Dave

[Stuart]

Jo

When I was at work for Nat West Before RBS  we did the very same thing on an industrial scale with four 500 HP centrifugal chillers , in those days main frame needed chilled water at 5 deg c so we had to run chillers anyway .

we took the waste heat form the computer hall and put that over the chillers we then used pump down to load the chillers to max just under surging, with the heat that they produced we heated the rest of the building with enough left over to heat the greenhouses , evan then in winter we still had to run the cooling towers

with research done do for a project by me I concluded the best way to provide the heat source for a domestic was from a bore hole that gave you the heat even in winter at night

yes its a very efficient system but has a ten year pay back over head

Stuart

[steamer]

When I set up the heat in the shop....a quick investigation proved that there wasn't ANY insulation in the walls of the garage!....

The walls were plastered...and in good shape...so what to do?

Using a staple gun, I stapled quilted mylar duct insulation over the plaster.  It's about 3/8" thick and has a insulating value of R9.   That did wonders....though the inside of the shop is all shiney metalic mylar now...at least it's warm!

Dave

[Jo]

Dave: I live out in the sticks so I don't have luxuries like gas fed to the house.  My oil fired boiler is increasingly unreliable and getting expensive to run. The main house heating is now achieved via high efficient log burners which provide cheap heat because I ask every man and his dog to bring any spare noggins for my fire and I currently have about two years worth of it stock piled .

My thoughts are if these heat exchangers are actually value for money I could consider investing in a couple to maximise the use of the free electric or is this false economy and actually the pay back period is such that I should continue burning the power directly with the existing electric heaters.

I understand the heat exchangers also operate as air conditioners in the summer, when I have got oodles of free electric to burn .

Stuart: I have considered ground source heat pumps. In fact my 130ft well would seem to be an ideal source. But I understand the trend now is to install a pipe grid array fairly near the surface, only a few feet down. But you still have to buy the heat exchangers which I think may be the expensive bit.

Dave: I have 4" thick insultation on the walls covered by another 3/4" of chip board for insulation and another 12" above the workshop ceiling.

Jo

[Jasonb]

Jo an air source heat pump should give you a reasonable amount of heat out for the energy you put into the unit and circulating pump. I have been thinking of getting one for my koi pond but not done so yet.

You need to look at the COP figures as they do drop as the outside air temp drops so you may only get out twice what you put in when air temp is around freezing in which case it would take a while to recoup the ?1000 or so outlay

1" of snow here this morning I have one convector with a frost stat that will come on if the temp gets very low and another that I turn on when in the shop which is well insulated so it keeps its heat once upto temp. The worse thing is if I've not been in there for a few days and the metal surfaces take a lot longer to warm up than the air, this is always a good time to hacksaw off a big bit of metal by hand.

J

[Arbalest]

Insulation is the key. If you can insulate the space really well it won't take much to heat it. Many times on TV in various programmes they've said it does'nt get cold enough in the UK to warrant central heating - provided you insulate properly! They then go on to show examples of houses in Sweden (where it drops to minus 20) which are well insulated and don't have central heating, just small electric heaters in the bedroom when it gets really cold ...

The other trick is to divide the space into smaller areas if you can and only heat the spaces you work in, no point in heating storage areas for steel stock etc. just keep those areas dry.

[dvbydt]

".....For every kilowatt of electricity used it can produce the equivalent of up to 3 kilowatts of heat output even when it is cold outside..."

Steamer -
Are you Sure about that Ian?

Yup, and that is only the inexpensive ones (?400 ish). If you go to high pressure, you can get up to 9 to 1 return. Remember that there is heat available for extraction from ambient air down to -273 degrees but it gets harder and harder to get it out at low temperatures!

Ian

[Ramon Wilson]

I would agree with the remarks  by 'Arbalest' on insulation as my situation would seem to confirm.....

I have a 14 x 14 ft wooden workshop which has an 14 x 8 ft extension down one side access to which is through the inner wall. All walls in each area are lined with 3mm hardboard with 2" thick fibreglass bats in the reccesses between uprights , the roof treated the same way. The 3/4 inch wood floors are covered with hard board the joists of which stand on paving slabs to allow circulation of air. The original windows were fitted with double glazed units but these now form part of the inner wall between the two areas. The extension has a 10ft window (3 panes) which is double glazed.

Originally I used to heat the first area with two (permanently on) 240W greenhouse heaters but these would only take the chill off on the coldest of days and heat would have to be boosted by a 3KW fan heater - expensive all round and the Chancellor not a happy bunny (that's Sue not George) When the extension was put on two oil filled radiators were purchased from one of the DIY chains for less than thirty quid each. Best investment made for the workshop I'd say. With one in each area the workshop is always warm and, thermostatically controlled, a definite improvement on electric consumption was soon noticed.

Capable of switching to 1, 2 or 3KW they are only ever on the 1KW setting except for the very coldest of days when they might see the 2KW for a short period and the fan heater has long gone in the bin. I can usually work with just a tee shirt and shirt under the old blue 'engineers' coat throughout most of the winter and as a bonus I can leave things laying around without the worry of rust as condensation appears non existant.

Were it possible I would insulate the floor - layer of polystyrene foam under the hardboard - as the feet sometimes feel a bit cold if it's a bit raw outside but that's impossible now with all the kit in place.

One thing's for certain it really does have to be absolutely bloody freezing  to keep me from my daily fix  and yes that's where I'll be tomorrow

Regards - Ramon

[Stuart]

to explain to those who think we are discussing over unity devices ( perpetual motion )

the apparent gain from the electrical input is from the free heat extracted form the environment ( air /water / rock )


you cool the heat source and that energy is transferred to the output.


to carry on from my previous post ( wife came in with the car dashboard lit up with fault codes darn cars are to clever for there own good BMW )  after a about 15 years of use and the use of R11 the design engineers convinced the bank that they would save money by dumping the energy saving system and run the chillers on normal load and run boilers to heat the rest of the building , Cooling tower now run all the while and we had to install two 2 million BTU boilers with a 6 inch gas main. it was not a success for us that ran the system electric bills up and a gas bill to pay, but they still insisted they were right .


later I discussed this with the engineering dept at Manchester uni and they concurred with my views

heat pumps are the way to go  but do as recommended by others insulate the walls ceiling and floor with as much as you can get in but do leave room for your machines 


Stuart

[Jo]

One thing's for certain it really does have to be absolutely bloody freezing  to keep me from my daily fix  and yes that's where I'll be tomorrow

Regards - Ramon

I recomend a house lathe for use when it is likley to take (or is taking) too long to heat the workshop

Jo

[Ramon Wilson]

Oh I used to have a house 'workshop' Jo - lathe, mill etc - it was all originally in the third bedroom but even I got fed up with 'swarf in the hall' - not exactly a recipe for wedded bliss either

Honestly it's a very rare occasion that the cold keeps me out of the 'shop - this morning it's 2or3 degrees below outside and the temp in the main area is 62 and 66 in the inner with nothing more than the rads on at 1KW.

I'm still distracted - am in the inner one at present but not for much longer now. Hope to be back making swarf in the new year.

Regards  - Ramon

[Jo]

Oh I used to have a house 'workshop' Jo - lathe, mill etc - it was all originally in the third bedroom but even I got fed up with 'swarf in the hall' - not exactly a recipe for wedded bliss either

That is not currently a problem . I am very vigilant with the dirt devil making sure that those friendly little bits of swarf are not trying to sneak around the house or to attempting try to join me in bed

At this time of the year with subzero temperatures in the morning it can take best part of an hour to get the workshop up to a good working temperature. The heaters are on timers but increasingly I find I want to be out playing earlier and earlier, there is just too many wonderful engines to make and too little time to be making them in .

Jo

[Ramon Wilson]

Oh I used to have a house 'workshop' Jo - lathe, mill etc - it was all originally in the third bedroom but even I got fed up with 'swarf in the hall' - not exactly a recipe for wedded bliss either

That is not currently a problem . I am very vigilant with the dirt devil making sure that those friendly little bits of swarf are not trying to sneak around the house or to attempting try to join me in bed

At this time of the year with subzero temperatures in the morning it can take best part of an hour to get the workshop up to a good working temperature. The heaters are on timers but increasingly I find I want to be out playing earlier and earlier, there is just too many wonderful engines to make and too little time to be making them in .

Jo

That maybe where your problem lies Jo - I leave my rads on all the time letting the thermo take care of the switching. Letting the workshop go cold then heating it up again is, I'm convinced, inefficient at best not to mention the potential for condensation problems but I would agree convection heaters are expensive to run in this fashion. Oil filled rads appear to be the cheapest electric form of (24hr)heating and of course are still delivering heat once tripped out. I don't think I could better my system for it's initial and running costs.

I've been in there since eight this morning and just before I came in for a coffee I noticed the temp has risen to a balmy 71 - feet are a bit cold though as it is quite cold outside - ice still lying about.


On another note - I'm finding it difficult to quote a post that already has a quote in it - as you can see above - could some one enlighten me how you separate out the previous quote please?

Regards - Ramon

[Jo]

Raymon,

Just delete the bit between the [quote author].....[/quote autor] for the post you don't want, included.

Where I can only get out in the workshop for a maximum of 3 days a week it seems silly to heat the workshop unnecessarily: it only costs money. However when I retire  it will be another matter.

Air source heat pumps: I am going off the idea. I have been nattering to our maintenance guys and they brought up the noise problem. I should have thought I have had the experience of having to work with an air conditioning unit immediately outside my window at work before. I understand that in some countries you are not allowed to install these devices within 5meters of your neighbours boundary because of this noise. Best to know earlier rather than later.

Oil filled radiators: I have one of these in the bathroom to exploit the free electric power. I must say it is very good but not they are not as cheap to initially buy as fan heaters.

Jo

[Stuart]

Jo

thinking out loud so to speak I do think its important to maintain your pride and joys ( machines ) at a temp that is above dew point to that end rather than heating the space why not heat the machines on the days you are not in the WS


just strap on a couple of say 100w black heat bars to them to keep the condensation at bay


My solution was to insulate the WS well ( its a small one only a Myford conny and a sx3 mill ect ), and use a 500w oil filled heater to keep the chill off , with the lamps on it soon warms up


Stuart

[Jo]

Hi Stuart,  I do try to heat the machines, on the days I am out playing: I have a old greenhouse heater that I sit on the Colchester master. I also play the fan heater on the harrison which is the other heavy machine. The net result is that the general workshop has never gone below 5 degrees even when it was minus 15 outside  even after I had not used it for a few days.

An alternative to black heat bars is just to use good old fashion light builds mounted in a ceiling light bulb fitting plugged into the mains. The advantage being that they used to come in 20, 40, 60 and 100 watt variants.

We all know there is nothing worse than having to handle cold tools .

Jo

[Arthur Dent]

Very interesting thread, particularly now, as I am in the process of insulating my shop and trying to figure out my heating arrangement.
Black heat bars?  Is that something like heat tape?  That's something I hadn't thought about, but sounds like a good idea.

[Stuart]

they are about 1 inch by 5 /16 thick the length varies with wattage

they as the name suggests do not get red

this is the type of thing
http://www.thermalcorp.com/band_heaters_strip.php
http://www.directindustry.com/industrial-manufacturer/strip-heater-73668.html


Stuart

[Arthur Dent]

Ah, I see.
Yes, we use these elements in curing ovens at work.  I had not heard them called "black heat bars".
Thank you very much.