![]() ![]() Why You Need a 6-Point Socket to Remove a Water Heater Anode Rod.It wasn’t there when we started, soooo… Dry Ice Thing When all was said and done, I found this thing in the bottom of the cooler. ![]() If I were you, though, I’d double-check those calculations before leaping to any particular conclusions. Well, considering the rough-and-ready measurements and the fact that the freezer isn’t at STP and that I’m ignoring gas leakage and a bunch of other stuff, a factor of two error is spot on. s) and doing that over the course of an hour requires 5 W.Sublimating 0.07 lb = 0.031 kg requires 18 kJ (18 kW Call it 11 W.Ĭross check: Wikipedia says the enthalpy of sublimation at STP is 571 kJ/kg. in ) and an internal surface area of 304 in^2, the cooler leaks heat at 38 BTU/hr.Assuming the cooler foam has R=4 with units of (ft^2 The freezer is around 0☏: a differential of 109☏ across 1.5 inches of Styrofoam. The temperature of sublimation is, according to Wikipedia, -109☏. ![]() Maybe a side effect of having the cooler’s cavity nearly full of dry ice? Or the freezer ran defrost cycles for the other two?Īnyhow, to a back-of-the-envelope resolution the cooler loses a bit over 0.05 lb/hour of dry ice. ![]() I’m suspicious of that low number for the first stay, too. Which, as it happened, was about half an hour in a bike trailer during a rather hot afternoon.Ī) 7.2 to 6.7 lb -> 0.5 lb / 15 hr = 0.033 lb/hrī) 3.8 to 3.0 lb -> 0.8 lb / 11 hr = 0.072 lb/hrĬ) 2.7 lb to 2.0 lb -> 0.7 lb / 11 hr = 0.064 lb/hr Starting weight: 9.2 lb gross, so I lost quite a bit in transit. In between withdrawals, the cooler sat in the freezer and and the dry ice quietly sublimated here’s how the weight varied between uses. It used to be plenty cheaper in the old days, evidently, but everything else was, too. For what it’s worth, dry ice costs $3.50/pound under 10 pounds, then $2.75/pound over that. I started with “10 pounds” of dry ice in a half-pound Styrofoam container with 1.5-inch thick walls the total weights include the container. I used about a pound of it a time to mumble. For reasons I’m not at liberty to discuss, we had a cooler of dry ice pellets in the freezer for a few days. ![]()
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. Archives
December 2022
Categories |