Chiller questions

Hi guys. The last week or so I have started collecting some information to make my own water chiller during the summer. In the beginning I thought it would be a good idea (and would keep it simple as well) to go with the "evaporator in a res" approach. Although, I am trying to make this as compact as possible so i was thinking about making my own heatexchanger. Is it really difficult? Could you provide more info like links for making a heat exchanger from scratch?
Also, I am not sure I will be able to do this, so I still keep in mind the "evaporator in a res" thing. Could you tell me how small can the res be in order that the evap will cool the water efficiently? Thanks in advance.

You can build your own heat exchanger, let me look for some links.

*Casts Life 2 on this thread*

Those links never materialised, and now I'm interested in this information. Any help, guys?

Basically the easiest way is just some coiled up like 3/4" copper tubing with some 3/8" copper tubing inside of it.

The refridgerant goes into the 3/4" tubing from the captube and expands, while the water flows through the 3/8" pipe inside of that.

The refridgerant expands, pulls all the heat out of the water, and chills it.

Pretty simple, but I can draw something up if you want, or you can PM if you want any more dtails, JoT.

Sounds very compact, but also possibly difficult to do. Wouldn't it be a pain to try and keep the smaller diameter tube near the center of the larger tube? How would you seperate the water tube from the refridgerant tube to feed the watercooling system? Also, how many feet of this rig might be necessary?

Thanks for your help, sandman

That sort of evaporator inside another tube will work well, but I don't see the point. To do this, you would have to discharge the system, remove the evaporator, braze on your new custom made evaporator/heat exchanger, and change the cap tube length to match your heat load. Then you would have to vacume and recharge the system (with a gas you are certified to use, or by someone else) and then tune the charge. If you are going to do all this, why not just make a direct die system that will be smaller, cheaper to run, have less parts, cost less, and stomp all over the performance of the chiller.

The only real advantage of a chiller is that you can make them by just submerging the evap. and you don't have to touch the actual phase change system. If you are going to do this anyway, just make a direct die.

The one other interesting feature of a chiller is that you can run the chilled water on your video card as well, but it would be easier to just coil some copper pipe or do something else around the suction line coming from the evaproator, or along the top surface of the evaporator itself. You will get better temperatures, and a more compact system.

something like this right?





what size do you conside big. you can easily build a descent chiller in a descent size space. they don't all have to have 10gallon reservoirs

matttheniceguy said:

That sort of evaporator inside another tube will work well, but I don't see the point. To do this, you would have to discharge the system, remove the evaporator, braze on your new custom made evaporator/heat exchanger, and change the cap tube length to match your heat load. Then you would have to vacume and recharge the system (with a gas you are certified to use, or by someone else) and then tune the charge. If you are going to do all this, why not just make a direct die system that will be smaller, cheaper to run, have less parts, cost less, and stomp all over the performance of the chiller.

The only real advantage of a chiller is that you can make them by just submerging the evap. and you don't have to touch the actual phase change system. If you are going to do this anyway, just make a direct die.

The one other interesting feature of a chiller is that you can run the chilled water on your video card as well, but it would be easier to just coil some copper pipe or do something else around the suction line coming from the evaproator, or along the top surface of the evaporator itself. You will get better temperatures, and a more compact system.

Click to expand...

I don't want to do direct die -
A: Because I just sunk a crapload of money into upgrading my watercooling system, which now cools the GPU, CPU, and NB.
B: Because direct die would cool only the CPU.

I very much like the tube inside a tube idea. Also, it's no problem to do all the things that need to be done for the tubes because my grandfather is a certified air conditioner repairman (thus he'd have all the things I need, and can do all the gas stuff)

Oh yes, I did a lil bit of math and figured out that I can do 10 coils of 3/4" tubing (each coil would be 5" across) and I'd then have 180" (15') of chilled tubing. Should I try to do more, or is it possible to do less? Is there a noticable benefit to having lots more chiller tubing?

JoT said:

Oh yes, I did a lil bit of math and figured out that I can do 10 coils of 3/4" tubing (each coil would be 5" across) and I'd then have 180" (15') of chilled tubing. Should I try to do more, or is it possible to do less? Is there a noticable benefit to having lots more chiller tubing?

Click to expand...

While, chiller's aren't my specialty, in a cascade you generally use 15-20', and that's with a 500+ watt heatload, so I'd estimate that something like 8-10' would be enough.

JoT said:

Sounds very compact, but also possibly difficult to do. Wouldn't it be a pain to try and keep the smaller diameter tube near the center of the larger tube? How would you seperate the water tube from the refridgerant tube to feed the watercooling system? Also, how many feet of this rig might be necessary?

Thanks for your help, sandman

Click to expand...

It doesn't have to be centered, that won't really matter that much.

YGPM

Neato, sounds like this is a very cool possibility (pun intended)

sandman, if you wouldn't mind, could you draw up some sort of diagram to indicate how it is set up? I'd really appreciate it

the benefit to having a larger amount of water that is being cooled is that you can over increase chillers heat capacity for a short time. just think about it. if you have a 5 gallon reservoir at -30C fluid temp, you can oc your hardware higher than having fluid temps of -15C (better cooling = more oc duh). Now, the fluid temps will eventually heat up due to the heat load of the system and temps will equalize to a point where your cooling fluid will not increase of decrease in temperature (lets say -20C)

if you would over saturate your systems oc with a 5 gallon reservoir the system could hold the saturated oc for 25 minutes, theoretically speaking, before the temps would equalize and you'd have to reduce your oc. with a smaller reservoir (1 gallon lets say) you would only be able to over oc your system for 5 minutes compared to the5gallon res. just to give an example.

so, the more fluid that you have precooled before firing up the system, the you can hold an over oc. this mostly appeals to the benchmarking crownd who only need to get a few solid runs in wit their system pushed beyond its limits.

if you are just going to use the chiller for normal games/ surfing/ etc a tube in tube hx will do (forget all of what i just said above)

btw, ygpm too

the only thing with chillers is that the actual cpu die temps are alot higher.
ie 0c with chillier and say between -40c to -20c with a small compressor die temps.
you can get copper for like $6 and make evaps with drill press.

things like 16mm sheet with 2mm lids. and say 40mm square blocks fit the new A64 chips sweet.
direct die is really worth it.

I'm going with the chiller, sandman is helping me out with that