Instructables

how do i build an ice block maker that makes iceblock big as truck battery in 2 hrs? what would be the things i need?


Re-design4 years ago
This will certainly work but I DON'T recommend to you that you use it.

A water tap with a electric valve.
An insulated watertight form the size of a truck battery.
A control system.
A storage tank for a compressed gas like lpg, butane.  THere others but I only have experience with these.  An inert gas that wont harm the atmosphere would be better.
Plumbing with electrical valve to control the flow of gas.

Set up the controller so that it will flow 1" of water into the form and stop.  Then opens the valve to the gas so that the flow of super cold vapor cools and freezes the 1" of water.  I don't know how long it will take but I've seen it happen almost instantaneously.  You would have to adjust for your flow rate and the the thermal impact of the chosen gas.

The controller would then add 1" more water and gas it again.

Repeat until you have your "truck battery" sized block of ice.

Again, this is not a suggestion of what you should do just an explanation of how it could be done if this was a theoretical problem.

You could do this with cooling coils but to freeze a block all at one time would be very hard.  But use enough energy to take out the heat energy in a block of water and it'll freeze pretty fast.
ooh ooh, how about a thousand watts of peltiers?

or...if you're lucky like us Canajuns...just put the water outside for a while -- for half of the year its an option.
coolcurrent4u (author)  frollard4 years ago
 This is not helping me
It was and it wasnt - it A way of doing it - as with re-design's idea - it would work, but its super-obfusicated and not a very good way to do it...

Stick with the 'buy a freezer' option.
coolcurrent4u (author)  Re-design4 years ago
 diagram, parts names, schematics would be preferable. please help me
frollard4 years ago
Easiest:  go on craigslist or kijiji or freecycle and get a cheap/free working deep freeze.  It will have the biggest area to work with and enough horsepower to get the job done.
frollard4 years ago
Coolers (air conditioners) are often rated in 'tonnes' - how many tons of ice per hour it is capable of freezing from some temperature to solid.  I bet if you search somewhere you can find out a conversion between tonnes of ice frozen, btu, and watt-hours.  (whatever your homework asks)

That in mind, you need to know how big a block we're talking about - figure out the volume, and convert to weight in tonnes.  (water is 1 gram per mL)

Then get an appropriate refrigerator capable of moving that much heat.


...or do the math the old way - 1 joule per ml degree c...
battery 20 x 25 x 30cm = 15000cc's = 15 Liters = 15000 grams

15000 joules per degree C (to chill the water to 0)

Say 10 degrees (if the water comes out the tap cold)

150000 joules to cool the water

heat of fusion for water = ~333 joules/gram

15000 grams * 333 = 4,995,000 joules

add = 5145000 joules = 5145 kilojoules of energy

5145 kilojoules in watt hours = 1429 watt hours.

2 hours to do that much work = 714 watts at 100% efficiency.  I looked and looked and can't find figures for % efficiency of coolers, so work with that.
coolcurrent4u (author)  frollard4 years ago
 i will  have about six containers or 8 in this machine. the size of each is about the size of two car batteries placed side by side
Okay, then to confirm you'll need 8x as much refrigeration to still do 8x as much water in the same amount of time.
"Tons of refrigeration" is actually MELTING ice at 0 °C. Its around 3.5kW

Steve
enthalpy for melting or freezing is the same, just opposite...I wasn't sure if it included the smaller temperature change energy or just the freezing...good to know :D
jeff-o4 years ago
Is your goal to make the ice block maker in 2 hours, or for the block to freeze in 2 hours?  Making it shouldn't be a problem, but you're going to need a massively cold freezer to completely freeze a block that size in 2 hours!
coolcurrent4u (author)  jeff-o4 years ago
 my goal is to make turn the water into ice-block in 2hrs. i will  have about six containers or 8 in this machine. the size of each is about the size of two car batteries placed side by side
Eh, you could make the box out of aluminium (good heat conductor) and line it with the elements of a big freezer, then insulate around, basically you'd be making the innards of a big freezer work on a smaller volume.

What's this for anyway? Because a big bag of ice isn't expensive and if you get them from the bottom the freezer they're pretty much a big block of ice. 
coolcurrent4u (author)  killerjackalope4 years ago
 Am making the machine like a refrigerator. It should turn water placed in aluminum containers into ice in 2hrs. the machine is just for making ice-blocks. I need it for a university project.
orksecurity4 years ago
You could probably freeze it solid in 2 minutes or less by immersing it in LN2 (liquid nitrogen). Some other superchilled liquid would also be a good bet. If it's surrounded by air, I'm not sure you'll get enough heat transfer.
coolcurrent4u (author)  orksecurity4 years ago
 orksecurity
That would definately not be ok for a machine somebody else would use. I could do that if i wanted to do a physics experiment
 
 
That would do it alright.  Hadn't even thought of LN2.   But then never used it myself either.
lizzyastro4 years ago
Find an old fridge, one with a suitable size "freezer" section, get it degassed, and remove the freezer section box - make sure its the right sort of size, but it will be a neat little unit for pulling lots of heat out of the water. Place that in an insulated, water proof box. Buy a Danfoss condensing unit, like their  Optyma units- something with a fair amount of reserve capacity, which will obviously have a cooling capacity of about 1kW at -10 C -ish .

Get it plumbed to your freezer section by an AC specialist.
Fill with water.
Switch on.

Steve