Came to a bad realization

AWESOME Todd!!!!!! I'm gonna hafta save your post for future reference. I assume it can be interpolated into different water volumes by simple relation? :)

Now... Since you're the whiz can you calculate the cooling effect of a thawing a 2 litre bottle of ice on 100 gallons of water to show everyone that it's not worth the bother! Fans man, fans! Todd just proved it!!!!!

Great!!! I love it...

Guy
 
fans, evaporation, greenhouse effect

fans, evaporation, greenhouse effect

1. The glass over the water is most likely the main problem. You are creating a greenhouse. The glass will allow nearly all the IR to pass into the water and prohibit evaporation from occurring. If you only have the VHO's don't worry about water splash. Clean the tubes before your photoperiod begins if salt spray build-up is a problem.

2. Fans, fans, fans. Add fans blowing across the water surface if the natural evaporation is not enough to maintain your water temp. Since you have a sump you have more surface area to use.

3. By lowering your room temp you will be able to exchange more heat from your glass and water surface.
 
I did some calculations (below)
Click to expand...

LOL... Fahking Kolledge Kids.... I can't believe I used to be one. You need to slow down, or smoke more Dope man, you're going to pull something important in your brain one of these days' and not be able to pass your boards...

Hehehe, some quick calculations...

Gotta love it man, I _AM_ gonna miss that brain of yours :-)
When you leaving us? I gotta have another meet before then.
Hehe, I'm still chuckling to myself. Folks at work are really going to think I'm weird. (as if the "Live Fish" packages and exploding Astaxanthum Powder weren't enough)

- Mac
 
This definately won't be on my boards...

This definately won't be on my boards...

Kevin just reminded me that I better get back to the library and study for the boards but this is much more fun, so go ahead and get some more coffee Andy (and whatever else Kev) as this is interesting stuff (in response to Guy's question) ==>

Conclusion #2: In order to cool Andy's tank from 88F to 78F by putting 2liter bottles full of ice in the sump rather than using 1 gallon of evaporation you would need 10.66 two liter bottles of ice!!! Glad you brought that up Guy, I hadn't thought about it that way...man, I really appreciate my 2.3 gallons per day of evaporation as I would need another refrigerator to hold the 24.52 bottles of ice each day!!!

Calculations #2:
-Assume that the ice is at 32F and will be melted and then heated to 78F
-heat of fusion of ice tells us that it would take 333 KJ to turn one KG of ice at 32F into one KG of liquid water at 32F. Then to heat the water we would use the specific heat of water to determine that it would take 106.8 kJ to then heat that water to 78F. So per liter it would take 439840.8 J to turn the ice into water at 78F.
-Recall, we needed 8060000J to cool Andy's tank 10F, so we would need 19.55KG of ice to do this.
-Since ice is less dense than water we also have to take into account that we could only put 1.834 liters of water in each bottle to end up with 2L bottles completely filled with ice (otherwise we would have a bunch of broken bottles).
-So as I said above, with 1.834 KG of ice in each bottle at 32F and with time to allow this to completely melt and then warm up to 78F you would end up needing 10.66 bottles to replace one gallon of evaporation!

Man, I'm sure that this stuff isn't on the boards!!!!
Talk to you guys later.
Todd
 
hey Todd do you think one of those bypass machines for open heart surgery would work? they have to heat and cool right?


I think I might be able to find one in the basement in the halway maybe.....
 
For those of you planning on putting axial fans in your enclosed cabinet blowing on your sump. Don't forget that the humid air that your sucking through that fan carries some salt with it. Salt is an excellent conductor and more then likely over a period of time you will be heating your water with a small fire instead of cooling it. So if your adding fans to your sump make sure their mounted on the cabinet blowing in fresh air and not just circulating. Take this from someone who has had this happen to him. 2 years ago on my 65g I pulled the idiot maneuver of blowing a fan directly on my sump. Luckily I was in the living room when she blew and started on fire!
 
raise the lights, recommend 8 - 10" for MH and a fan when you do them. its the glass tops for sure - greenhouse effect it is. you'll end up with temp issues in july/aug maybe - a/c or cellar I'm hoping for. run the lines through the toilet, yeah my wife would like that :lol:
 
Todd,
Wouldn't it be more efficent if you removed the bottles of before the water got to 78F? Doesn't the rate of cooling slow as the temperatures equalize? It would take more bottles but less time. Or did you plan on putting all 10.66 bottles in the tank at the same time?
 
Craig,

I'm not sure that I totally understand your question, and my answer is probably out in left field, but this is my understanding.

If your goal was to increase the rate of cooling then it would be most beneficial to replace the bottles right after they melt and while they are still at 32F as overcoming the heat of fusion of water requires more energy than the specific heat (actually, adding more bottles would be the quickest, but lets assume that we are talking about one bottle).

Also, you will get faster cooling when there is a greater difference in the temperature between the outside of the bottle and the tank water because when two particles collide they will be more likely to have different kinetic energies and thus will be more likely to transfer energy from the high energy particle to the low energy particle (cooling).

However, while it will take longer, warming one bottle from 68F to 78F will lower the temperature of the tank the same amount as warming that same bottle from 32F-42F.

Hope that I'm not totally off on this one.

When did you say you were going to be in Burlington? Let me know and I'll do my best to get a day off.

Talk to you soon,
Todd
 
Todd,
You've got the gist of what I was trying to say. In an effort to cool the water down quickly, you want to the largest delta T. That's why all the 10.66 bottles at one time would be the quickest. Additionally you need to expose as much surface area of the frozen bottles to the warm water as possible, so slightly submerging them would cool the water the fastest. Ain't thremo great!

About Vermont - we are going to Stowe August 3-10.
 
Re: This definately won't be on my boards...

Re: This definately won't be on my boards...

ToddsReef said:
-Recall, we needed 8060000J to cool Andy's tank 10F, so we would need 19.55KG of ice to do this.
Click to expand...
You just made me blow a mouthful of drink all over my monitor! LOL!!! RECALL?!?

OK, folks. Would everyone that recalled please raise your hand...
 
Pete! Surprised to see your post over hear in this forum. Hope your monitor is OK (LOL), this thread is just a tad more technical than we usually get in the URS forum :)

Andy...cardiac bypass should work, I think you can get a heck of a deal on them this time of year...I think about $500,000 :D

Craig...I think that the real key is EVAPORATION for cooling and soda bottles for soda. I'll shoot you an email about Burlington...hopefully by then I'll know of a decent place to eat up there...hmmm...Wendy's or McDonalds...glad we have time to decide :p

Todd
 
We have enough MD's among us I bet they might be able to find a well used one somewhere. Probably cheaper to go with AC. JMO:p
 
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