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The idea is to refridgerate the fire trucks water tank to bring the water temp within 1 or 2 deg of freezing .
This means the ignition point of materials around the fire is lower because the air temp has been reduced due to hose water spray .
I am guessing the ignition point where near materials
start to burn because of heat would not be linear so any attempt to take energy out of the enviroment would be an advantage .
Burn victims will have instant cold spray and firemen have more freedom in the heat around the fire .
Next step - snow flake blowers .
Does cold water put out fire faster?
http://amos.indiana.../coldwaterfire.html
Yeah, but just a little bit. [jutta, Jun 30 2008]
[link]
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1) the water would should already be cold by the time the firemen reach the fire .
2) The enviroment , the enviroment , the enviroment . Those firemen don't wear that thick gear for fun . |
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How would a fire on a really cold day travel compared to a blistering hot day ? |
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A very quick bit of thermo - for which we need to make an assumption or two. Assumption - water sprayed on the fire is 100% evaporated <as a result of heat from the fire>. |
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Specific heat of water - 4.181 kJ/kg.K <kilojoules per kilogram to change temp by one kelvin - in a broad sense constant from 0-100 degrees centigrade>
Heat of vaporisation - 2270kJ/kg <kilojoules to take liquid water at 100 deg C to steam at 100 deg C> |
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So, case 1 - you start with room temperature 25 degrees C water in the tanker. You'll sap 2583 kilojoules taking 1kg of water from 25C through to steam. |
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Case 2 - you start with icy water <but no ice> at 0 degrees C. You sap 2688 kilojoules per kilogram making steam. That's 4% more than with the luke-warm temperature. |
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Even if you mess about with the assumption I made, saying that only 1/2 of it boils - That's still only an increase of 8% or so resulting from cooling the water. |
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Spend your money and effort on a bigger pump, more reservior space, and a better nozzle. Better yet, use salt, or even better again, use ethyl glycol, or some other antiboil component to change the thermal properties of your spray water. Perhaps an inert one, as I'm guessing the ethyl glycol may be combustible. |
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So much for my "very quick bit of thermo " claim. |
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why would you want to make your water less evaporative ? steam displaces air. |
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I was more aiming to increase the heat of vaporisation, not prevent it. You'd need to look at the despersal method. Frankly, I think plain water is the best bet, and lots of it. |
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Guys, just don't set fire to things in the
first place. |
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The real thing is that it is not just about boiling water .
The water gets sprayed on surfaces and the air around the fire as well as the fire . |
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Given a wall of hot flame and a choice between a pipe of water(25DegC) and a pipe of of near zero water, I know which I would choose, If only for my personal safety . |
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Put it another way . Ask a soldier which ammo he/she wants, the 100% penetrating or the 102% . |
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Aside, tech in flash temperature reduction of fast flow fluids would be an investment for future generations . |
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