First up, how many bananas in a container? A standard forty footer holds 20 pallets. There are maybe 6 boxes of bananas per level, 10 levels, and 100 bananas per box? 120k bananas per box.
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So that's more, right? 120k * 15k = 1.8 GigaBananas? Nope.
11 proslijeđenih tweetova 388 korisnika označava da im se sviđaPrikaži ovu nit -
15,000 containers will be referring to TEUs - twenty foot equivalent units. 120k * 7.5k = 900 MegaBananas? Nope.
9 proslijeđenih tweetova 372 korisnika označavaju da im se sviđaPrikaži ovu nit -
Is it weight? A banana weighs about 125g. So, around 15tonnes per forty footer. That's far short of the maximum of 28 tonnes.
9 proslijeđenih tweetova 348 korisnika označava da im se sviđaPrikaži ovu nit -
So what is it? It's power.
9 proslijeđenih tweetova 361 korisnik označava da mu se sviđaPrikaži ovu nit -
Even the biggest container ships - for example, the Emma Maersk with around 11k fully laden TEUs - only have 1k reefer sockets onboard. Assume those are all filled with forty footers. We are down to around 1k * 120k = 120 MegaBananas.
6 replies 16 proslijeđenih tweetova 508 korisnika označava da im se sviđaPrikaži ovu nit -
Wow, big difference! But, it gets worse. Those reefer positions all need power.
7 proslijeđenih tweetova 371 korisnik označava da mu se sviđaPrikaži ovu nit -
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
7 proslijeđenih tweetova 389 korisnika označava da im se sviđaPrikaži ovu nit -
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.
9 replies 7 proslijeđenih tweetova 418 korisnika označava da im se sviđaPrikaži ovu nit -
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! That's changed what you are doing in the engine room.
9 proslijeđenih tweetova 369 korisnika označava da im se sviđaPrikaži ovu nit
That’s not right. It’s easier to keep things cool than frozen, but you just assumed maintaining coolness requires DOUBLE the power! Not right.
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Odgovor korisniku/ci @Robotbeat
ARGH. Please can you assume that... given that this was what I did, I know?
0 proslijeđenih tweetova 0 korisnika označava da im se sviđa - Još 4 druga odgovora
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