Sensible Nick,
You may be an engineer, good for you, I'm sure you are a good one.
My first hand experience is running a snow and ice removal business. I make good money doing it.
We use diesel fired snow melters. We use propane fired torches to melt snow on some properties where chemical snow melters cannot be used. One account is a botanical garden and any chemicals must be specifically approved, ice melters are not approved due to potential damage to the soil. I don't fully agree, but they pay me to do it their way. The main point would be that their cost per square yard is the same as using chemical ice melters, so basically propane is not an outrageous idea.
We use and install diesel fired, propane fired, wood fired, natural gas fired, coal fired, electric fired and geo-thermal in ground ice and snow melting systems that heat the ground. This is very often less expensive, more proactive and better for the environment than Plow, Sand and Salt programs (PSS)
What we have found is that the traditional PSS is not always the best solution. For example the snow melters in many cases burn less diesel than trucking the snow away. We turn it into water and send it down the storm drain, where it will go anyway. Less polution, less congestion on the roads, fewer trucks for us to maintain.
So, we can agree to disagree I guess. For my part I'm going to do my best to help the OP make something that will work based on what I know and have built or bought myself. I know his idea may not seem to be the very best, but a lot of good things have come from what others thought to be silly. You can either encourage a hobby and learning and progress, or you can say it won't work, without running any numbers, with no first hand experience, based only on your gut feeling. Think about it.
Mr. HE
Firstly, Thanks. I am. :thumbsup:
*Acknowledgement of mutual approval of each other's professions/experience*
Don't get me wrong: I'm not looking at this as a pissing match. I'm totally happy to listen to/appreciate other's opinions, and yes, I'm sure that in some cases melting the ice with thermal energy is going to be the only usable answer. As you state yourself: A botanical garden is one case with a justifiable reason for avoiding salt. Can't argue there. Runways are another... though Oslo in Norway (for example) don't do that because they see it as environmentally irresponsible. They do fine with well organised ploughing/brushing, and have only ever stopped operating once due to heavy snow. For an Hour I think...
So.. Heat can be justified... But a Gravel driveway? Seriously? Sure.. If you throw enough energy at it the ice will melt, but if it were
your own wouldn't you just grit it?
Again I agree with you when you say that Trucking snow away does indeed use fuel, but in this case that's not a consideration. The OP was asking about local Ice
For my part I'll be trying to encourage the OP to take what I see as the easier, less expensive, longer lasting, environmentally responsible, (and totally boring) option.
*************
Gut feeling aside, let's go with your experience. If I may draw on your knowledge, I'd like to ask some questions.
1. Would you say that a steep gravel drive, of 400' length is going to be easy to melt the ice on, while avoiding the problem of molten water re-freezing?
2. Which will take the most time?
a) Melting ice on a 400' driveway with propane
b) Sand/salting the driveway
3. Which will have the most lasting effect?
a) Melting ice on a 400' driveway with propane
b) Sand/salting the driveway
4. Which do you see as the most environmentally responsible solution
in this scenario
a) Melting ice on a 400' driveway
b) Sand/salting the driveway
Anyway: Whatever the mixed opinions, I genuinely look forward to seeing a space-heater concoction being whacked together, and look forward to the results.
NC4AB: Please do Let us know how it goes: even if it's a colossal flop we'll all learn something from it I'm sure.
Moving away from the ice thing..... Aside from heating stuff, it may have
another use. Here in Sweden the road-crews use propane torches for killing weeds in some of the cobbled areas: It's another case where chemicals are not an option, and fire is seen as the lesser of two evils....
So it may work for that use too... unless um... unless you're in a forest: then that may not be such a neat idea.. :ashamed: