toyotaboy02 wrote:a Co2 system would probably be harder to trigger.. if it wasn't, then automatic extinguishers at companies might have something like that. It would be very easy to activate a cheap aquirium pump and shoot it through a nozzle to spray it.. And if your worried about the water making things worse, you could always fill it with that waterless water that 3m developed.
Either a H2O or CO2 system would use the same type of trigger. Likely a electronic solenoid valve triggered by a simple thermocouple sensor, or some such. Either system would also have to be battery powered (trickle charged battery hooked up to the mains to maintain the charge) because a tree fire could possible involve an electrical fault that may indeed cause a loss of AC power to the system.
The idea of using a aquarium pump would simply introduce another point of failure in the system. Not only that, but a pump would have to lift the water to the top of the tree (6ft plus) and still be able to provide enough pressure to spray the water down over the tree in a great enough rate to be effective. If you were to use water, a more reliable method would be to pressurize the water with a inert gas like CO2, but using straight CO2 would be simpler because the gas could deliver itself without help from any pump or pressurization system, because the CO2 is naturally under pressure.
In the space that you could place an H2O system that could contain 1ftÂ³ (approx 2 gal), you could place a CO2 system that could contain more than 40ftÂ³. Not only can you store more volume of CO2 in the same space, it would also weigh less than half as much as a H2O system. 2 gallons of water is 16 pounds by itself plus all the extra hardware require to deliver the water to the top of the tree. Compare that to 5 pounds for 40 cubic feet of carbon dioxide under pressure with no extra hardware required to lift the gas to the top of the tree.
EDIT: Just thinking about this... A CO2 system could simply use a perforated tube running up the tree with no need for the angel (use whatever tree topper you like). The tube would flood the entire area of the tree with the gas. CO2 would also give you the ability to use a smaller diameter tube, making it easier to hide the system.