Cooling School project: Phase Change

Are you talking about a TIG welder? Never heard of an Argon torch in my welding classes.

 

Burnout21 he probably doesn't want to spend £50 on postage though.

 

the lump of copper i have measures 70mmx 70mm x 30mm it think? its let over from when id done my water block.

 

we need it to make a block for on a cpu.

 

that i guessed!! lol!

 

your best bet is to find a metal shop, or supply yard near by and buy some copper blocks from them. shipping copper is expensive.

 

Compressor->Condensor->gassline with a dryer->Evaporator->suction hose->condensor


TBH it isnt actually that hard to make but it is expensive. You dont need to weld anything but you'll need some type of gas torch to sweat together all of the fittings. The Evaporator (what connects to the cpu) is the hardest part to make. If you do a simple waterblock design you'll probably hit about -5 degrees celcius but if you have one made professionally you could hit -70 if you're setup is well built.

www.xtremesystems.com

ask alot of questions
pm chilly1 about his evap block. I think it's about $140 shipped for everything you need

 

Peltier cooling is easy. Put foam around the socket, fill the socket with grease, slap on the waterblock. (I've done it and it works fine)

 

I think suicide risk assessment is easy. An airline pilot thinks that flying an airliner is easy...

It is easy to someone who knows what they are doing. I was talking about someone who does not even know what a Peltier is...

What you are ommitting from your description is:
1. What capacity Peltier you selected, and why;
2. How you mounted it with the correct mounting pressure;
3. How you feed the Peltier.

Not unimportant details.

 

A+ advice.

No offense but it looks to me this dude is not fit for water cooling let alone pelt and phase.

The third point is very important, but ill add another point. How to cool the pelt properly to prevent disaster.

Ive seen a pelt melt a copper and alu toped waterblock. As well as melt the barbs and tubing. It evaporated the water and dam nearly set the guys house on fire.

If you look around hard enough you realise that pelt cooling is more times than not more dangerus than phase. As well as way more hasle than phase.

However if you are stuborn and still want to make a phase unit start with something thats easier. Chiller... With a small btu (5000btu ac works very well) Air conditioner you can take it apart and saw off the front fan that blows cold air in the room and put that condenser coil in a small cooler withought rupturing the lines then your battle is over. After that fill the cooler with a mixture of alcohol and water and pump it through a water block.

Make shure you insulate the block and tubing as well as the socket like you would on any other sub dew point cooler.

This ensures that you have a profesionaly built phase unit with all electronics intact. Just set the thermostat to max and the compressor on high and you should see well below ambient temps on it. And if you want to get fancy you could replace the thermistor on the ac and get a proper valued one that could turn the motor on and off keeping the liquid at a constant temp providing the thermistor has contact with the water through an insulated heat conductor such as a strip of copper.

 

OK, for a school project, phase change is definitely a no go. Simply too many mistakes to be made and learned from before you'll get a working system.

Think about what you asked in the first post and what is expected of you.

Two things from this.

I get the impression this is a short project, yes? And you not only have to build something but also perform experimentation on it.

Now depending on your course and what exactly your project should involve, you should only be spending a third or so of your time allowance. You need to give time for research and experimentation. You also need to consider a project where your experimentation has some meaning. You won't believe how much easier this will make your project to write up. I'm also assuming you need to submit a report at the end of this.

Think about it this way.

All the school practicals you will have done will have been designed to make a point. Believe me, having designed practicals before, a LOT of thought would have been put into this. And likewise you need to make sure that there is something you are gonna be able to draw conclusions on.

This involves ensuring you can control certain variables and measure others for analysis. This would be extremely difficult with a phase change system as understanding all of the variables and accounting for them would be enough to keep you busy for a whole degree and PhD.

As an example, if you want to study some form of advanced computer cooling, peltiers are ideal.

There are several ways you might approach this.

You would need to design a cooling system for the peltier and a way to apply a heat load. The heat load can be achieved by attaching your peltier to a working computer, but there is a lot of risk here, and how do you know the heat load is constant. (this is what I mean by controlling variables. You will get high marks for demonstrationg that you have considered all of these little details and performing thorough work, not by using all of your time to build something exotic then not having time to experiment properly. It would be considered that you hadn't "finished")

You could build a die simulator to approximate the heat load from a processor, thus controlling the heat input, allowing you to vary something about the cooling setup. You could vary the voltage across the peltier and see how that affects the cooling performance. Or vary the design of the waterblock cooling the pelt or vary radiator performance. These are all experiments which prove important scientific principles but are only really possible with a lot of equipment your school "should" have. You will probably have to construct and calibrate thermocouples to take temperature readings (think more research and testing to achieve this which is all things your teachers will want to see)

I do hope this helps.

If you take nothing else from this, please take on that there will be a lot more to this than simply the construction stage. The initial research will probably account for a large portion of your marks. WRITE EVERYTHING DOWN in a notebook as you go on. This will make writing up a lot easier. Don't be afraid to ask for pointers but if you want a good mark, you will need to understand what it is you are doing and will need to PROVE this in your report. The introduction and research is a good way to do this.

All they want to see, is that you have started your project with a view to studying "something". As such your report should demonstrate that everything you have done has all been aimed at this goal. You should have done some research to find out what you want to test, what equipment you will need, acquired everything you can, and built what you can't acquire, then performed experiments to study "something". If it doesn't work, then you need to think WHY it hasn't worked and write it all down. You can still get good marks for such a project provided it shows effort and understanding.

Good luck and I hope you enjoy it.

8-ball

 

well, vacation is over so we discussed everything with our teacher.
He thinks phase change etc. will be to expensive.
But he said it might be possible to mix two liquids/gasses together, and when the reaction takes place the temperature will lower.
But i can't find this reaction on the internet. Does anyone know something about this?

 

Well... if your using the lquid to remove heat from its suroundings its an endothermic reaction if your using it to dump heat into its enviroment its exothermic. There are very few endothermic reactions that you would be able to do.... i dont know any off the top of my head.

 

Moreover, this would be totally unsuitable to PC cooling, which needs to be a closed cycle. You can't keep topping up the two liquids and draining the spent waste product.

8-Ball gave you some really good advice here. I'd suggest you read it and follow it.

 

why is it that sometimes this forum seems to stop helping ?

i have had some of the best support i could ask for from here and other modding forums when i have been stuck on a project or similar

but every now and then it seems that everyone is too busy seaying "you cant do it" or "you dont have the skills required"

if thats your opinion then fair enough but at least offer the help thats being asked for along with you opinion.

as 8-ball said the approach to this will be what you get marked on not the finished product the same as when you do a math problem its not the answer that they want to see but the workings out.

if you go here and read all the notes this guy has bulit a fully working phase change cooler from parts as you want to do.

it cover everything from tools and materials needed through to testing the system.

also read through all the projects on http://www.icecoldcomputing.com/ they even have a reasonably good section on the evaporator design.

you may find after some research that you will not be able to build a phase change cooler as the materials needed in particular the refridgerants (is that spelt correctly?) you will need a licence to buy.

so a good approach may be to do an entire project on accelerated pc cooling solutions and after showing your research and reasoning go for a peltier setup as the only option available to you as a school student you could then go for a project such as the one zapwizard designed for a pc ac system. see zapwizards site for details i thjink its under the projects page. when you have made it you could even try to modify the design to improve it if possible.

good luck i hope this all helps and try to keep this thread updated with your progress

cheers

T

 

Sometimes, no help can be offered. If the person lacks the basic skills/knowledge/resources, the best advice is to leave it to those who do. If a person asks for castles in the sky, the best advice may be to keep both feet on the ground.

Now we can all flash our superior knowledge by lengthy explanations and provide lots of links and get this person into a confused twist, but the purpose is to help him. And sometimes the best advice is: "This is too difficult. Don't do it".

And part of that approach is to stay realistic and not get overambitious. Hubris kills.

 

point taken

no offense meant

 

In my last post i didnt mean to be unhelpful the truth is i dont recall any endothermic reactions that would work in this situation of the top of my head.

 

Hmmm I just spotted this thread I build modify and repair phasechange units if the you lived in the UK or could make your way over and needed help no problems......
Your best bet is to go see a fridge engineer near to you who will be able to help you out or do the brazing and charging.
With pahsechange units for computers you need to make sure when you braze that you purge with oxygen free nitrogen or all your pipes get clogged with carbon deposites, which is a bad thing as this will get clogged in your filter or capillary tube. .
Oh yeah some countries like the UK it is illegal not only to vent refrigerants but also to use and handle refrigerants without the proper training and certification

 

My main problem with the idea of people making this devices is the fact that they require soo much planning and expensive equipment. If you consider making you own stuff buying the equipment makes a $2,000 premade phase change unit look cheap as dirt. NOt worth it imho.

As for waterblocks you will need a ridiculously steady hand and a plan on how you are going to make it.

I would stray away from anything to maticulous for a school project. How bought making your own fan winding you own brushless motor making the controller circuit designing fins etc. try to get help via. A areonautics engineer about aerodynamics of fins. My suggestion.