Re: Carrots

[Kevin C Houston <hous0042@maroon.tc.umn.edu>]

On Wed, 3 Jan 1996, Timothy van der Linden wrote:

> >In fact, you would have less water in a hydroponics system than you would 
> >have in frozen food.
> 
> I assumed freeze dried food, so a lot if not all (using special prepared
> food) water would be extracted. Of course it won't be tasty at all.


and there could be severe vitamin depletions.

> 
> >If the trays are three inches wide, and 9 inches deep, and they are 
> >stacked about two feet apart, then we can put 16 trays side-by-side, and 
> >stack four levels high (1st level at 0 feet, 2nd level at 2 feet, etc.)
> >then one "stack" feeds 64 crewmembers and we will need 16 stacks to feed 
> >the whole crew.  The volume of the "carrot Room" allowing 4 feet at the 
> >end of each row, and 2.5 feet between stacks, and placing the water pumps 
> >in the 2 feet below the floor level, will be:
> 
> In 72+18 days a member eats (72+18)*3=270 carrots
> 24 carrots per foot, so a member needs 270/12=11.25 foot

sorry, I rounded to 11 feet

> One stack has a length of 9*16*4=576 foot

you have misunderstood the dimensions:  (if x and y directions are 
paralell with the floor, then z is from floor to ceiling)

and each tray is 3 inches x, 11.25 feet y and 9 inches z
they are placed 16 side-by side giving each level the dimensions
4 feet x, 11.25 feet y, and 9 inches z
each level is stacked with a 2 foot level-to-level spacing, giving a 
stack the dimensions of 4 feet x, 11.25 feet y, and 6 feet z
each stack contains 16*4= 64 trays (each 11.25 ft tray feeds one crewmember)
and 16*16=1024
> 
> >From here I've a real hard time following your calculus...

it's not calculus, just simple arithmetic.

I'm assuming that the end of each row will be taken by machinery, as will 
the two feet of sub-floor space.  there must also be a interstack space 
to allow people to move about freely, I'm assuming 2.5 feet.  Then I 
calculated the volume of water in the trays and in the supply lines
I divided in^3 (or cu. in=cubic inches) by 12^3 to get cu ft (or ft^3) 
then I multiplied by .02831 to get m^3 the conversion from m^3 to Kg is 
the standard 1000 Kg/m^3 (yeah, I know that only works for 4 deg 
centigrade, but let's not quibble over such smallness) 
after estimating for aditional machinery, I then went on to show how many 
square "karrots"  (6in by 2in by 2in) we would need for each crewmember) 
and how much space and mass they would take up. (assumeing that the mass 
of a "Karrot" is just that of the water.
> I wonder, do plants that grow large food (relative to the amount of leaves)
> use more oxigen than they create?

no, the creation of the food (6H20 + 6CO2 + energy --> C6H12O6 +6O2) 
removes most of that oxygen from the system (plant)  it is the non-food 
portion which consumes oxygen that can not be recovered.  you can see 
this by considering what happens when you eat the food.  the oxygen that 
the plant exhaled combines with the sugar that you ate to produced energy 
plus CO2 + H2O

> 
> >This should end the farm vs warehouse debate unless a flaw can be found 
> >in my calculations (always a distinct possibility)
> 
> I found at least one error, and have some doubts about the volume and how
> much water is there in a single tray?

I think that I have answered your "so-called" errors, as for the volume 
calculation, here it is again.  3 x * (11.25 *12) y * 9 z (where x,y&z 
and directions) =3645 in^3 *1024 trays=3.73E6 cu in /(12^3) =2160 ft^3 
(well, what do you know there was an error.  Luckily it was in my favor, 
so that means that theoretically al least it takes even _less_ volume) 
but we still need water in pumps and supply lines and whatnot, so let's 
call it 2500 ft^3 *.02831 = 70.775 m^3 (I called it 71) =70775 Kg 
assuming a 29225 Kg for machinery and such = 1 E5 Kg for carrots that 
take up (2.5+(16*4)+2.5) x * 15 y *8 z =8280 cu ft = 234 m^3

> (It took me a while before I figured out that 1 feet is exactly 12 inches)

When you post equations, you can write in SI if you want to but I find 
when i am estimating sizes, that American system works for me.  I will 
answer any questions you have on relationships etc.

Kevin