> Those reefer positions all need power.
We used to factor around 4kW for a reefer... so that would be around 4MW total. Easy!
Problem is, bananas are not average.
Most frozen cargo is taken onboard frozen. It doesn't take much power to keep it frozen at -21degC
> Bananas are different though - they are often packed warm, and brought directly to the ship.
They are also kept at +14degC. This means the refrigeration needs to work harder.
> We are now looking at as much as 20kW to cool that container when it comes onboard, and 8kW to maintain the temperature. We've jumped to 8MW at least!
I don't buy that. Sure, cooling to 14C will require some extra energy for a limited amount of time, but why would 4 kW be enough to keep a -21C container at that temperature while it takes 8 kW to keep a container at 14 C. Doesn't make any sense. Of course that doesn't mean the conclusion that regular container ships cannot go 100% bananas is wrong. At least @cybergibbons seems know what they are talking about. I just think there is a gap in the argumentation or that I just misunderstood.
EDIT: @cybergibbons address this objection [1]. What I understand is that frozen cargo is stored at -21C but then allowed to warm up wheres bananas are cooled and then held at a constant temperature in the ship.
2 comments
[ 1.7 ms ] story [ 12.2 ms ] thread> Bananas are different though - they are often packed warm, and brought directly to the ship. They are also kept at +14degC. This means the refrigeration needs to work harder.
> We are now looking at as much as 20kW to cool that container when it comes onboard, and 8kW to maintain the temperature. We've jumped to 8MW at least!
I don't buy that. Sure, cooling to 14C will require some extra energy for a limited amount of time, but why would 4 kW be enough to keep a -21C container at that temperature while it takes 8 kW to keep a container at 14 C. Doesn't make any sense. Of course that doesn't mean the conclusion that regular container ships cannot go 100% bananas is wrong. At least @cybergibbons seems know what they are talking about. I just think there is a gap in the argumentation or that I just misunderstood.
EDIT: @cybergibbons address this objection [1]. What I understand is that frozen cargo is stored at -21C but then allowed to warm up wheres bananas are cooled and then held at a constant temperature in the ship.
[1] https://twitter.com/cybergibbons/status/1213593041740664832
https://en.wikipedia.org/wiki/Latent_heat