Would the liquid co2 in hot water work???
Yes it would work, but you have to have a
fog machine specifically designed for the liquid CO2 with special regulators designed for the pressure and the product. There are
fog machines on the market that use LN2 (liquid Nitrogen) and also liquid air (80% LN2 and 20% liquid Oxygen). There are advantages and disadvantages. The machines that use liquified gas are more expensive than comparable dry ice units, but, depending on the cost of the gas or the cost of the dry ice in your area, the LN2 is often far cheaper. When working as TD at the Meadowbrook
Theatre a few years back we purchased an LN2 machine to replace a dry ice
unit and wound up saving several thousand a year in dry ice costs. The annual Christmas Carol runs over a month with IIRC 10 and sometimes 12 performances a week, each performance using, again IIRC, (it was a couple of years ago) about 100# of dry ice. The LN2 comes in a large dewer that lasts 4 or 5 days, no one ever handles the cryogenic product, no daily trips to
pick up the dry ice or to lose 20% when trying to store it overnight. Very large venues like theme parks can pipe the LN2 or liquid air to the machine and have 500 or 1000 gal tank outside the building that gets refilled by a tank truck. One big advantage is the
fog can be continuous for hours on end if need be as the liquid can be
fed continuously into the machine at any rate you desire.
The LN2 has no related health hazards as it is essentially the same as 80% of the air you breathe, however it does displace oxygen so performers can not be totally immersed for more than a few seconds. Liquid air is even better (but far more expensive) because you can have performers totally immersed for any length of time. This prompts a word of caution, when using dry ice or LN2
fog, if you have an
orchestra in a pit, you must prevent the
fog from cascading over the front of the
stage and filling the pit as you are now suffocating you musicians.
The liquid machines all work by spraying a mist of the cryogenic liquid over a surface of hot water and the result is the same highly condensed white vapor that is heavier than air, is chilled and dissipates before it rises. The cold
fog flows down hill like water and will not rise as it warms up.
Fog created by chilling the output of a machine that heats up
fog fluid will always begin to rise as it warms up. Fast dissipating fluids are the best way to counter this but there will still be some degree of rise.
Generally the liquid product machines are cost effective if you are using a lot of dry ice and do a
lot of
fog. for smaller amounts or one shot FX for a short time, the dry ice machines or a chiller on a
fog juice machine are usually a better choice.
one of the best commercial dry ice machines I know of is the
City Theatrical SS6000 dry ice fogger
City Theatrical (click on dry ice
fog on the menu at the left) , but at a list price of $8250, it is pretty steep for most budgets. The best small commercial machine IMHO is the
Lemaitre Pea Souper, don't know the cost of that one right off.