I am trying to design a device that will store pollen at -30 using dry ice. I have a YETI cooler that stores dry ice and it will last a week or two in there. Is there a way anybody can think of to make it last longer? Like maybe put the YETI in a REDDY-ICE machine like you see outside 7-11? If the YETI cooler stays colder in the REDDY-ICE machine then it should last longer (I won't have to replace dry ice as often). Please help, I have been thinking of the best way to do this.