I'm thinking of getting a paraffin space heater for the garage. Paraffin would be very convenient because I have a ready supply of heating oil.
My heatloss calculation says I need arounf 6kW, so something like this:
TIA
========================== Hi Grunff, The last device I saw similar to this was used to heat the shed/warehouse of my local fruit and veg dealer. The noise it made was incredible! Of course it may not be representative of the genre, but it's worth checking the noise output. If the garage is attached to your house and you already have oil-fired CH,(with spare capacity) could you use a couple of wall- or ceiling-mounted Myson fan convectors?
Cheers,
Ian
Thats a lot of heat to loose. Be cheaper in the long run to reduce the heatloss with a bit of insulation.
The times I've seen these things in operation in the past I've heard them first. Think small jet engine without turbine wine, they really do roar. And remember you have 6kW of heat coming out of hole what 12" dia, that air is HOT and there is an awful lot of it. Not really suitable for a normal sized garage, a small industrial unit is a better location for these things.
It's a reasonably large building - 6x8m. Single skin, but with
50mm jablite + 11mm OSB on top (or it will have when I'm done).I like the thought of that! But not really the thought of listening to it for hours on end.
Good point also. Thanks.
It may not be as bad as you think.
My garage is around half of that distance from the house once pipe runs are taken into account.
I ran an underground duct of 150mm soil pipe between the two and ran two lengths of 22mm Speedfit through it, each thickly insulated and then taped together as a pair.
The garage has its own pressurised system with pump operated by thermostat and four radiators capable of delivering about 8kW, although in practice only about half that is needed.
At the house end there is a stainless steel plate heat exchanger connected to the CH circuit on the primary side via a zone valve. A flow switch on the secondary side responds when the pump in the garage runs and opens the zone valve and runs the boiler.
I felt it prudent to separate the systems so that anything going wrong in the garage circuit did not compromise the house circuit. The garage circuit is also filled with a Fernox Alphi antifreeze/inhibitor diluted to be good down to -18 degrees.
The results have been excellent. The temperature drop through the length of flow pipe is less than one degree, so the run is not resulting in much heat loss.
.andy
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That's really interesting. I've even got a spare ss heat exchanger which I bought ages ago for a project. I could put the garage pump on a 7 day timer to suit, get a bunch of second hand rads, and hey presto.
You say the garage circuit is pressurised. How did you achieve that?
Thanks Andy.
So around 110m^2 surface area (2m high walls) or approx 55W/m^2. I would have thought 50mm jablite was better than that on it's own let alone with skins either side.
Assuming a 25K temp differential that gives U-value for the *complete wall* of 2.2W/M^2K. I can't find any real figures for 50mm Jablite but the ones I have found the highest is 0.5W/m^2K, less than 1/4 of the value implied by your heatloss...
Very definately tiring and possibly loud enough for long exposure to be a problem to your hearing...
You might be able to duct the hot air it to several vents along the length of the building rather than just blast it into one (now hot) corner.
OK. A bit more detail.
I used a 100kW GEA Ecobraze heat exchanger. This was to minimise the temperature drop between circuits rather than a need to transfer that much heat. I located the exchanger (it's slightly bigger than a house brick) in the airing cupboard having clad it in some spare Celotex. The motorised valve and flow switch are there together with a filling loop (there's cold mains close by), a pressure gauge and a 3 bar pressure relief valve with exit to the outside.
At the garage end there is a 10 litre expansion vessel and another pressure gauge and relief valve - basically a sealed system kit.
There are a couple of automatic air vents at high points as well.
At each end of the long pipe runs I put lever ball valves to be able to isolate, and the same each side of the pump. The inhibitor/antifreeze is relatively expensive - about £15 a container and I needed four. IIRC there is about 30% inhibitor/antifreeze.
The system was initially filled from the airing cupboard end after the inhibitor had been added.
I did need to do a part drain down to fix a radiator valve problem. To cope with this and not lose the water/inhibitor/antifreeze, I made up a gadget using a garden sprayer (one of the chunky Killaspray types from B&Q for about £20.). Conveniently, this has an 8mm aluminium tube for the lance which will go nicely into a compression fitting. This was then adapted so that it could be connected via a non return valve in the garage. Basically, I can drain the system into a container and then reintroduce the liquid and pressurise back up to
1.5 bar using the sprayer without adding more water.The pump is controlled using a room thermostat/time switch with night setback set to about 10 degrees.
The arrangement with this and the flow switch gives an effective form of control without needing to run cables between the buildings (apart from the mains one to the garage of course.
The only issue I can think of is whether 60m (round trip) of 22mm pipe is going to have too much resistance. OTOH you only need about
6kW.... I would check with one of the pipe vendors on that point.My main motivation was being able to use the economy of the gas condensing boiler - I oversized the radiators grossly to allow for enough output even at 60 degree flow. It also meant not needing to worry about ventilation for fuel burning appliances or introduction of a lot of water vapour which is bad news in a workshop.
.andy
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Thanks for that. I'll give it some more thought, do some digging, price it up, and see what I come up with.
Walls are 3m high at one end and 2.5 high at the other. The roof is box profile steel with 50mm jablite underneath (will have as soon as I've put it up anyway). I also neglected to mention the f*** off big windows - single glass, 5m x1m at one end, 5m x
1.5m at the other. I went for single sheet partly because of cost, and partly because my healoss calculation said I'd only save 600W by going double.I may be off a little, but not by a huge amount.
I think the idea of a paraffin burner is well and truly scrapped. Too many clever people saying no.
I'm thinking about eithe AndyH's cunning second circuit plan, or a second oil boiler just for the garage. It will all depend on what I can find - the garage is not a top spending priority right now.
Thanks for your input.
Seriously, Id'd get a proper solid fuel stove or even paraffin stove - that has a flue, so you exhaust all the water to teh outer air.
Bloke I knew in a garage built his own stove and flue that ran off used engine oil. had some kind of fan in it, and relied on red hot burner rings to vaporise and ignite the oil once it was up to temp using wicks etc.
The fumes off internal vented paraffin stoves are vile beyond belief, and the condesnation is awful, especially if teh place is unisnualted with cold walls - the water will pour off the cold surfaces.
But not, as I once saw, about 20 ft away from a running 500 MW alternator, full of hydrogen (that's how they are cooled) hung with "No Smoking" notices!
Chris
Liquid Hydrogen or Di-Hydrogen Oxide?
Neither. Real gaseous hydrogen, and fairly pure..
.andy
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Well whaddya know - that is interesting.
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