SPACE HEATERS

I've got a 600 sq / ft commercial machine shop, and it's cold !

I have tried in the past a propane space heater , it warms up nicely, but the fumes give me a headache,

My friend has a larger building and he uses a diesel / kerosene space heater, and he says the fumes are no problem,

What does anyone think ?

Richard.

I bought a modest 22kw Draper space heater to run on red and allow me to do stuff in my draughty barn. It worked for a week before dying.. got returned and repaired, worked for 2 days.. got returned and claimed no fault found.. worked for a day.... finally I gave up..

If you're actually commercial and make a reasonable living at it then I'd say go for a 6-8KW reverse flow aircon system..inverter motors make them quite economical to run, you get the extra benefit of the ocassional hot summer, reasonably quietand if it's Daikin brand then a fair chance you can get away with not botherng to service it often (or at all)

With gas heaters you need to have some decent ventilation, like a wall bracket type fan to the outdoors. They are still worth it as the cost of electric heaters can be horrendous over continuous use. My old boss used them(a 3 phase type element heater)  9-5 and incurred a £1k bill over a winter month.

Michael W

Edited By Michael-w on 26/01/2017 18:20:02

Get a workshop gas heater, the combustion products run inside a heat exchanger and out through a chimney, a fan circulates shop air over the heat exchanger, if you fit it close to floor level the chimney will also radiate/convect heat into the shop like a wood stove chimney.

Serious insulation and draught proofing might be a more economic long term solution and can help keep a workshop cooler in summer too,

- Nick

I have a 6kw euqiv daikin in the livingroom and a 3kw in the main bedroom. When they were installed i questioned the slender wire going to the outdoor units.. didn't look thick enough to run anything. Fitter put a meter on the 6kw equivalent thing when it was running the draw was tiny... I'm sure daikin would give exact figures.

We use a couple of SIP Fireball diesel space heaters to warm a (bigger than yours) workshop at work. The larger of the two is rated at 52Kw & it really belts out the heat, but uses around 5 litres of red diesel per hour - the smaler one is about 15Kw & uses about 2 litres an hour. We have a diesel tank on site though (as we make our own electricity via a 200kva generator) so have no shortahe of the red stuff - I modded a 205 litre oil drum to have hose & valve that lives inside the works to fill the heaters & use a barrel full a week at the moment.

The only time it smells is if it is allowed to run out (when there is a cloud of vapourised, non-combusted diesel fumes) and after switching off (when it just whiffs a bit "dieselly". It doesn't seem to make as much condensation as the propane heaters we used before converting to diesel, a change made mainly due to rises in the cost of gas a couple of years ago - we were using a large (52Kg ?) propane cylinder a day & they went up to £70+ each.

I have not had any comments about my collegues feeling unwell due to fumes in the main workshop, though the workshop doors get opened during the day to get in & out with a FLT. The smaller heater was bought for a smaller workshop & the chap working there stopped using it after a while as he was getting headaches & attributed these to the heater fumes.

They can be finicky to keep running & are not maintenance free - there is a small compressor mounted on the rear of the fan motor that blows air through what looks very like a spray gun nozzle in the combustion chamber - this what draws the fuel from the tank & generates the fuel/air mix that is ignited by a continuous spark between two electrodes. There are a couple of filters to clean on the compressor inlet & the spark electrodes can short out through dust contamination (though that may be more due to our graphite machining environment & may not apply to you !).

HTH

Nigel B

You not using the heat from the generator?

Waste heat is so often wasted

Our local water works has 3 cathedral ships engines to run generators. They only run 2 at a time and in the winter they ruk.n the cooling water through the office radiators and get free heating for the office block.

Nigel B, the generator could probably supply much of the heat for the workshop by directing the air from the cooling system, be it a radiator, or an air cooled system.

Ian S C

Waste heat is so often wasted

Indeed so. I did float this as an idea some years ago, but there was no interest on the owner's part. Less initial investment (under £400 IIRC) for the large heater & red diesel bought 8000 litres at a time is (currently) quite cheap (around 50p / litre or less, I think). And it is possible we will move premises at some point, so less incentive to plumb up the place. I would like to use some of the unused electrical capacity of the generator to run a couple of 25 Kw electric space heaters, but that would also involve a fairly large capex as there is currently no spare capacity on the distribution boards.

I am aware of the potential effieciencies of using all the output from a genset - my brother is involved in such installations for commercial premises, using large V8 diesel engines converted to run on mains gas (different pistons to lower the CR & an ignition system fitted). IIRC he quoted something like 96% of input energy harvested from the generator, coolant & a heat exchanger in the exhaust system. I doubt that I could get that from our 20 year old 7.5 litre Iveco turbo diesels, though !

Nigel B

Heating the air in any large space will be expensive - infra red heaters (gas or electric) can be an interesting alternative. IR heats equipment/people, very little direct heating of the air. They were used in a large, draughty warehouse cum loading bay at a factory where I used to work.

Day rate for leccy is around 17p/kWh

Natural gas is around 4p/unit. No contest, even with a heat exchanger that is little better than 50%!

Electricity is a high grade energy source. Thermal is a lower grade of energy. Don’t waste resources.

Edited By Neil Wyatt on 18/04/2020 20:44:22

Mods,

As you appear to have dispensed with Lisa Martin, you may as well delete these last two posts, by me, on this thread.🙂

Log burning stove/fire? ...with a flue.

Ed.

I know it's an old thread but I agree with this as a consideration.I heat my workshop with a single 2kw infra-red heater and it's 215 sq/ft so three of those or a pair of 3kw should keep the OP's work space comfortable to work in, depending on height and insulation. I have a second one but two running make the place uncomfortably warm, I only use the second if I want to do a bit of painting on a large item.