I need to work out the max flow rate from the LPG tank in my campervan, water heater and space heater use approx 0.3kg/h of gas.

But for my cooker, I can only find the BTU output of the burners, which is around 19000BTU’s for the three hobs and the oven. Is it possible to convert BTU’s into kg/h?

Thanks 🙂

Don’t think so mate. BTU is heat output (Q).

assuming its BTU/hour then…………….

1BTU/hour = 0.3W
190000BTU/hour = 57000W

Assuming your on propane (orange cylinders)

Calorific value of propane (assumed higher heating value which should be the lower heating value but its all I have in my memory) 101000 kj/kg

So you have 57000j/s and 101000000j/kg

giving you 5.64E-04 kg/s or 2.03 kg/hour

Its LPG so propane/butane mix, but Propane usually makes up around 80%.

Thanks for the calcs…I want to buy a regulator which can be used whilst driving, it detects excess flow and cuts off the supply if a pipe ruptures (i.e. an accident). Cuts off at 1.5kg/h flow rate.

I took the highest BTU’s for my type of cooker, looks like I need to find the specific model as some have larger hobs. Don’t want it cutting out whilst cooking.

I got the 19000BTU’s from the online manual, just dug out my older paper manual and instead of BTU’s it uses KW’s and kg/hour, 5.9KWs / 0.42kg/h, which means I’m well inside the 1.5kg/h limit 🙂

Thanks for the help…reckon the first figures come from a more powerful version designed for static caravans perhaps.

I was thinking that the BTU output is “heat”. While the fuel will have a specific calorific value surely combustion efficiency needs to be taken in to account. Though I assume that most gas burner rings will be pretty much similar efficiency? So if you had 2 burners one that was 50% efficient and one that was 80% then surely the fuel volume used would be greater for the first to give the same BTU output?

I was thinking that 2kg/hr is a bit high.

I reckon there’s an excess zero in there somewhere either in my maths or the original information, as I got 57kW and the manual said 5.9kW (rounding error or different gasses?).

Quite right;
19000 BTU = 5.567 kW

can you use gas while on the move taking gas as a fuel for the car/van out of the question

Sorry I don’t follow showerman.

The van is diesel so its rare/expensive to use LPG as an engine fuel.

The tank is a red vapour take off designed for heaters and cookers, so you would need a black liquid take off tank to fuel the engine.

I think the tank would be ‘safe’ to leave turned on whilst driving to use the gas heater as it has a valve in the outlet that will shut off with excess flow, apparently if I took the regulator off and open the valve I’d get a small shot of gas and then nothing. But you can buy a specific regulator (Truma Secumotion (aka Drive Safe) that does the same job, but actually makes it legal to drive with the valve open.

thisisnotaspoon – I think you are correct…if you look back at your first post you actually put 190000 BTU instead of 19000. Thanks for the effort anyway…nice to know the maths matches what my manual says 🙂