CO2 Backup system for -80 freezers? - (Sep/19/2011 )
I've been considering CO2 backup systems for a -80 freezer in case of power-outage. Has anyone used such a system? Are they worthwhile?
According to Fisher a 50 lb cylinder of CO2 should last for about six months to a year without being used and keep a freezer at about -60 for about 8 hours in an emergency. Not sure how realistic this actually is.
I've never had to use one for real, but we had one on a freezer in my old job. As far as I can tell, when the freezer is working correctly, they still use the CO2, so when you need to use the backup system, the CO2 may or may not be full...
A normal (full of samples) -80 freezer will keep things cold enough for quite some time by itself provided it isn't opened while the power is off.
If you wanted a backup, you would probably be better getting a generator...