4 ms·

Is 24hr Cold Storage Possible Without Constant Power?

19 points by kaboro 7y ago

jayparth 7y ago
So interesting to hear about this niche problem. I never would have imagined that this would be an issue. When I read the title, I thought.. "duh... just use a backup generator", but the back of the napkin math doesn't seem to work out. I wonder what the economic impact of such a simple issue is. If you think of food loss from all processors in a whole country, it is definitely huge. What other seemingly small issues actually could have huge impact? What problems in my country are hiding right under my nose?
- extrapickles 7y ago
  There is heavy reliance on GPS for precision timing to make cellular radios work (why spend $100k on an atomic clock, when a $500 GPS unit will do). A few other things are starting to take a dependency on GPS (power grid, TV). Good roads can be hard to come by in quite a few areas. Even if a area has a road big enough to support a truck, they can be impassable during the rainy season.
- deleted 7y ago
  [deleted]
Simulacra 7y ago
There's a great book called "Absolute Zero and the Conquest of Cold" that talks about medieval cooling using salts, and later with ammonia and other chemicals. INAS but it sounded like the key thing was circulation and ventilation. So if somehow you could keep a pump working, by crank, solar, wind, water, you could keep it circulating. Likewise to some type of air displacement.
- jbob2000 7y ago
  If you can keep a pump running, then you may as well just use adiabatic cooling (gas under pressure gets cooler when released) to keep your stuff cool. That’s how your fridge works!
fragmede 7y ago
It's not clear to me what the "Coolbot Pro"[0] is doing. Near as I can tell, it is an aftermarket electronics kit to run a normal window or split system AC unit right above freezing, because otherwise ice forms on the unit and it stops operating until the ice has melted. [0] https://www.homedepot.com/p/CoolBot-Generation-7-WiFi-Walk-In-Cooler-Controller-with-Air-Conditioner-Control-from-59F-to-34F-CB-G7/308002549 https://www.homedepot.com/p/CoolBot-Generation-7-WiFi-Walk-I...
- BenjiWiebe 7y ago
  Yes. We use one, also in a reefer, to store cheese from our cheese plant. It's an alternate thermostat, basically. It has a small electric heating element that you attach to the AC unit's temperature sensor, and then you stick the coolbot's sensor in the fins of the AC unit. Works great!
excalibur 7y ago
In case anyone else is wondering, the spreadsheet gives a total cost for the project of 1,448,100.00, without specifying any units. I think it's safe to assume the price is in Nigerian naira. Given an approximate (Google-provided) exchange rate of 0.0026, this works out to $3,765.06.

19 points by kaboro 7y ago

So interesting to hear about this niche problem. I never would have imagined that this would be an issue. When I read the title, I thought.. "duh... just use a backup generator", but the back of the napkin math doesn't seem to work out. I wonder what the economic impact of such a simple issue is. If you think of food loss from all processors in a whole country, it is definitely huge. What other seemingly small issues actually could have huge impact? What problems in my country are hiding right under my nose?

extrapickles 7y ago
There is heavy reliance on GPS for precision timing to make cellular radios work (why spend $100k on an atomic clock, when a $500 GPS unit will do). A few other things are starting to take a dependency on GPS (power grid, TV). Good roads can be hard to come by in quite a few areas. Even if a area has a road big enough to support a truck, they can be impassable during the rainy season.
deleted 7y ago
[deleted]

Simulacra 7y ago

There's a great book called "Absolute Zero and the Conquest of Cold" that talks about medieval cooling using salts, and later with ammonia and other chemicals. INAS but it sounded like the key thing was circulation and ventilation. So if somehow you could keep a pump working, by crank, solar, wind, water, you could keep it circulating. Likewise to some type of air displacement.

jbob2000 7y ago
If you can keep a pump running, then you may as well just use adiabatic cooling (gas under pressure gets cooler when released) to keep your stuff cool. That’s how your fridge works!

fragmede 7y ago

It's not clear to me what the "Coolbot Pro"[0] is doing. Near as I can tell, it is an aftermarket electronics kit to run a normal window or split system AC unit right above freezing, because otherwise ice forms on the unit and it stops operating until the ice has melted. [0] https://www.homedepot.com/p/CoolBot-Generation-7-WiFi-Walk-In-Cooler-Controller-with-Air-Conditioner-Control-from-59F-to-34F-CB-G7/308002549 https://www.homedepot.com/p/CoolBot-Generation-7-WiFi-Walk-I...

BenjiWiebe 7y ago
Yes. We use one, also in a reefer, to store cheese from our cheese plant. It's an alternate thermostat, basically. It has a small electric heating element that you attach to the AC unit's temperature sensor, and then you stick the coolbot's sensor in the fins of the AC unit. Works great!

excalibur 7y ago

In case anyone else is wondering, the spreadsheet gives a total cost for the project of 1,448,100.00, without specifying any units. I think it's safe to assume the price is in Nigerian naira. Given an approximate (Google-provided) exchange rate of 0.0026, this works out to $3,765.06.