2L Coke bottle DYI Chiller
- Thread starter moneyman
- Start date
ryanhayes9
Active Member
what?????
laddy
Active Member
Freshwater freezes at 32deg, I'm assuming tap water not containing temperature resistent minerals or deposits will freeze somewhere around that temperature as well, and saltwater freezes at 28.5deg..........BUT THEY"RE ALL FROZEN AND AT THE SAME 25 DEGREES ANYWAY AFTER 24HRS!!!!!
......is this some LSAT prep thing?
......is this some LSAT prep thing?
moneyman
Member
Originally Posted by Laddy
Freshwater freezes at 32deg, I'm assuming tap water not containing temperature resistent minerals or deposits will freeze somewhere around that temperature as well, and saltwater freezes at 28.5deg..........BUT THEY"RE ALL FROZEN AND AT THE SAME 25 DEGREES ANYWAY AFTER 24HRS!!!!!
......is this some LSAT prep thing?
Thanks all...
ha ha... not lsat prep thing.
I am trying to cool my tank using a few 2L bottles kept in the freezer overnight. It is working well. Downside is that I have to keep floating a new bottle in the sump every hour during MH period. I was wondering what is the best.. I've been using tap water. I might try salt water to prevent it from freezing.
Freshwater freezes at 32deg, I'm assuming tap water not containing temperature resistent minerals or deposits will freeze somewhere around that temperature as well, and saltwater freezes at 28.5deg..........BUT THEY"RE ALL FROZEN AND AT THE SAME 25 DEGREES ANYWAY AFTER 24HRS!!!!!
......is this some LSAT prep thing?
Thanks all...
ha ha... not lsat prep thing.
I am trying to cool my tank using a few 2L bottles kept in the freezer overnight. It is working well. Downside is that I have to keep floating a new bottle in the sump every hour during MH period. I was wondering what is the best.. I've been using tap water. I might try salt water to prevent it from freezing.
bang guy
Moderator
Originally Posted by MoneyMan
Let assume the freezer gets to 25 deg F.
Q: Which bottle gets colder in the freezer say in 24 hr?
1) Filled with RODI?
2) Filled with tap water?
3) Filled with salt water?
Does it really mater?
Good freezers maintain 0F.
It doesn't matter what the contents are they will all get to the same temp. Saltwater is slightly more dense but the difference won't be significant.
If you do the math you'll find that ice only works on small tanks.
Fans cool very very efficiently.
Let assume the freezer gets to 25 deg F.
Q: Which bottle gets colder in the freezer say in 24 hr?
1) Filled with RODI?
2) Filled with tap water?
3) Filled with salt water?
Does it really mater?
Good freezers maintain 0F.
It doesn't matter what the contents are they will all get to the same temp. Saltwater is slightly more dense but the difference won't be significant.
If you do the math you'll find that ice only works on small tanks.
Fans cool very very efficiently.
moneyman
Member
Originally Posted by Bang Guy
Good freezers maintain 0F.
It doesn't matter what the contents are they will all get to the same temp.
If you do the math you'll find that ice only works on small tanks.
Fans cool very very efficiently.
I have 3 fans keeping the 90 gallon at a cozy 80 deg. Within 2 hr of MH, the temp gets above 83 deg. With chilled bottles, I can delay getting to 83 deg for 6 hours. On the 6th hours, the MH turns off slowly returning the water to 80 deg.
Good freezers maintain 0F.
It doesn't matter what the contents are they will all get to the same temp.
If you do the math you'll find that ice only works on small tanks.
Fans cool very very efficiently.
I have 3 fans keeping the 90 gallon at a cozy 80 deg. Within 2 hr of MH, the temp gets above 83 deg. With chilled bottles, I can delay getting to 83 deg for 6 hours. On the 6th hours, the MH turns off slowly returning the water to 80 deg.
bang guy
Moderator
Why not just set the heater to 83F and not worry about the temp swing anymore?
Mathematically, the only way the chilled bottles could be lowering the temp is if they get in the way of the light and reduce the amount of light entering the water. Unless, you're replacing the bottles every half hour or so.
Mathematically, the only way the chilled bottles could be lowering the temp is if they get in the way of the light and reduce the amount of light entering the water. Unless, you're replacing the bottles every half hour or so.
bang guy
Moderator
Originally Posted by cresh1966
Bang, if he were to put the frozen bottles in his sump and let water run over them would that work???????????
90 gallons of water vs a 2 liter bottle of cold water. If the bottle is ice at 0F and you put it in your sump it might take 15 minutes to warm up to 80F. This means that over the period of 15 minutes it can remove enough heat to lower the temp about 2 degrees. Meanwhile, the energy from the lights is warming the water back up faster than the ice is cooling it off.
If you used 4 bottles and swapped them out every 10 minutes with new frozen bottles you could stabilize the temp 3 or 4 degrees lower than without the bottles. This sounds like a whole lot of work to me when a single fan will easily outperform the water bottles.
Bang, if he were to put the frozen bottles in his sump and let water run over them would that work???????????
90 gallons of water vs a 2 liter bottle of cold water. If the bottle is ice at 0F and you put it in your sump it might take 15 minutes to warm up to 80F. This means that over the period of 15 minutes it can remove enough heat to lower the temp about 2 degrees. Meanwhile, the energy from the lights is warming the water back up faster than the ice is cooling it off.
If you used 4 bottles and swapped them out every 10 minutes with new frozen bottles you could stabilize the temp 3 or 4 degrees lower than without the bottles. This sounds like a whole lot of work to me when a single fan will easily outperform the water bottles.
moneyman
Member
2 computer fans are installed in the hood blowing air into the hood. The hot air is exhausted out in the back. An oscillating fan is on the hood to distribute the air around the room.
Here is my calculation:
90 gallon of water is 368 kg
2L of water is 2.16 kg
Assumptions:
1) Assuming tank tmp gets from 80 - 83 in 2 hours (difference is 2 degrees Celcius).
2) Assuming iced water is at 0 deg F
Using the famous thermodyanmic equation: Q = c mass (Delta temp in C), c = 4.186 kJ/kg for water.
Using assumption 1:
Q (80 - 83F; 2 deg C change) = 4.186 kJ/kg * 368 kg * 2= 3082 kJ
So, in 2 hours, the water will gain 3082 kJ of heat. That's 1541 kJ per hour.
Using assumption 2:
Q (-17C - 0C; 0 - 32F): 4.186 kJ/kg * 2.16 kg * 17 = 154 kJ
Q (Phase Change): 334 kJ/kg * 2.16kg = 721kJ
Q (0 - 27C; 32-80F): 4.186 kJ/kg * 2.16 kg * 27 = 244 kJ
Total = 154 + 721 + 244 = 1119 kJ
Summary:
In 1 hour, the heat build-up in my tank is 1541 kJ. Each 2L of ice at 0F can reduce heat by 1119 kJ. So, the net gain in heat is 442 kJ (1541 - 1119). If you put in 2 2L bottles (~ 1 gallon) per hour, you can reduce the temperature.
Here is my calculation:
90 gallon of water is 368 kg
2L of water is 2.16 kg
Assumptions:
1) Assuming tank tmp gets from 80 - 83 in 2 hours (difference is 2 degrees Celcius).
2) Assuming iced water is at 0 deg F
Using the famous thermodyanmic equation: Q = c mass (Delta temp in C), c = 4.186 kJ/kg for water.
Using assumption 1:
Q (80 - 83F; 2 deg C change) = 4.186 kJ/kg * 368 kg * 2= 3082 kJ
So, in 2 hours, the water will gain 3082 kJ of heat. That's 1541 kJ per hour.
Using assumption 2:
Q (-17C - 0C; 0 - 32F): 4.186 kJ/kg * 2.16 kg * 17 = 154 kJ
Q (Phase Change): 334 kJ/kg * 2.16kg = 721kJ
Q (0 - 27C; 32-80F): 4.186 kJ/kg * 2.16 kg * 27 = 244 kJ
Total = 154 + 721 + 244 = 1119 kJ
Summary:
In 1 hour, the heat build-up in my tank is 1541 kJ. Each 2L of ice at 0F can reduce heat by 1119 kJ. So, the net gain in heat is 442 kJ (1541 - 1119). If you put in 2 2L bottles (~ 1 gallon) per hour, you can reduce the temperature.
wattsupdoc
Active Member
I dont think the ice in your 2 liter is 0 degress f. 0 celcius yes.
bang guy
Moderator
Most good freezers can lower temps to 0F. I think that's a good assumption.
The only missing assumption is ambient room temp. If the ambient room temp is say 75F then it takes more energy to lower temp from 81F to 80F than it does to lower it from 82F to 81F. The difference is very significant. This is because the tank bleeds heat faster when the temp difference between the air & the water is greater.
The only missing assumption is ambient room temp. If the ambient room temp is say 75F then it takes more energy to lower temp from 81F to 80F than it does to lower it from 82F to 81F. The difference is very significant. This is because the tank bleeds heat faster when the temp difference between the air & the water is greater.