Miniature Heat Exchanger

[epion2985]

Looking for a miniature heat exchanger, coaxial preferbaly. Something about 4-6" long. Have been looking all over but no luck. Wondering if anyone knows where I can find one.

thanks.

[MeltedDuron]

why don't you make one? a little coaxial HX isn't that hard to make ;)

[n00b 0f l337]

Run some 3/16" thru some 3/8"

[[XC] mysticmerlin]

This is what I got for my chiller. Give it a look.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=220006107967&ssPageName=MERC_VIC_ReBay_Pr4_PcN_BID_IT

[the_new_guy]

dont try making one if you dont have some one to help you

[epion2985]

why don't you make one? a little coaxial HX isn't that hard to make ;)

Itsd hard to make a really small one, without kinking anything etc. I rather just buy one. Tube in shell is not good enough and a coaxial one on that scale is a duce.


This is what I got for my chiller. Give it a look.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=220006107967&ssPageName=MERC_VIC_ReBay_Pr4_PcN_BID_IT

I have the exact same one. To big. Need one half that size.

[Nyx]

use gauge 19 copper tubings guaranteee u can go small with less kinking.. the smallest i got was using a cone ~ between 10 - 15 cm (OD).

[[XC] mysticmerlin]

Itsd hard to make a really small one, without kinking anything etc. I rather just buy one. Tube in shell is not good enough and a coaxial one on that scale is a duce.



I have the exact same one. To big. Need one half that size.

so cut it in half and braze it back together.:stick: what about a plate HX?

[hatemi]

1/8 tube inside 8mm(5/16? ). You can make the coil very very small:)

[n00b 0f l337]

You can make small coils easier than large ones, just make sure you have an object thats heavy and dense to roll around.

[aussie_guy00000]

You have to remember that heat exchangers are all about surface area, the small the hx is the harder it is to maintain good surface area between the 2 fluids transfering the heat. You reach a point where you haven't got enough area, or it just becomes too restrictive. What sort of heat loads are you using it for, maybe anything smaller then the one mentioned above won't work. But at the end of the day making it yourself is probably the best option, don't know how small they make plate heat exchangers.

[n00b 0f l337]

^^
Not true, when a gas evaporates it removes heat from the surrounding MASS, surface area is only effective to some point due to the fact that the resulting gas is cold, and its coldeness spreads thru surface area.

In fact our HX's are almost all about MASS.

[aussie_guy00000]

Seriously dude, the more surface area a hx has the faster the heat will transfer. Think of surface area as a resistor and mass as a capacitor, the higher the resistance (less surface area) the less current (heat) will travel. The mass acts as a capacitor and helps dampen heat flux changes (heat tranfer rate), such as when the heat load changes suddenly, the more mass or material an object has, the slower it will respond to transient heat changes. That's why lots of thinner fins on a heat sink will disappate heat quick then the same volume of material shaped to have fewer larger fins. More surface area = faster heat transfer for a given delta K. Mass is important to help maintain regular temps.

[n00b 0f l337]

And we are after regular temps!

[jinu117]

Mass does nothing more than distribute heat... in our evap design, mass is there so we can distribute heat further up in essence in evap.
What really removes heat between two medium is surface area. Plate HX has such big capacity not because of mass but because of surface area.
Now, if they made Plate HX size half of what is available that would be awesome for many things we use :)

[n00b 0f l337]

I think it'd be worse if you had too little mass in your HX vs too little surface area. Tube in tube HX's dont have a lot of surface area but they have lots of mass and they work fine

[aussie_guy00000]

I think it'd be worse if you had too little mass in your HX vs too little surface area. Tube in tube HX's dont have a lot of surface area but they have lots of mass and they work fine

Tube in tube HX's don't have a lot of mass, you have maybe 1mm max wall thickness tube that seperates the 2 fluids exchanging heat. If's that's a lot of mass, then I don't know what a little is:confused:. The usually have a larger mass of material on the outside of the hx and are insulated to help prevent heat loss to ambient. The more material you have between the 2 fluids that you want to exchange heat, the more resistance to heat flow you have, it's just the way it works. Ideally, if you could just pour the 2 fluids into the one container, and allowed them to mix, you'd have the optimium heat transfer case, but you'd also have 2 mixed fluids depending on their miscibility :(. As I mentioned before A larger mass only helps to either dampen temperature spikes, or help to distribute a heat flux over a larger area. That's why heavy bottom pans are good for roasting, the heat will distribute itself more due to the larger mass and higher resistance to heat flux. Where as if you have a thin bottom pan, the heat will pass pretty much straight through from the heat source to the other side, and perhaps burn what eva you're cooking :D

[epion2985]

You have to remember that heat exchangers are all about surface area, the small the hx is the harder it is to maintain good surface area between the 2 fluids transfering the heat. You reach a point where you haven't got enough area, or it just becomes too restrictive. What sort of heat loads are you using it for, maybe anything smaller then the one mentioned above won't work. But at the end of the day making it yourself is probably the best option, don't know how small they make plate heat exchangers.


I know how exchange of heat works, and probbably better then you. This is not for two fluids either, I dont know what you assumed this was being used for, if you meant my chiller its a bit more complicated, it has 5 heat exchangers for various purposes. Never the less I have a task that requiers a very small one, such is the task, everything else has been considered. I just need a link, a phone number or a company which I can contact to get one as my time is more valuable (although that would be depandant on the cost)


To everyone else thanks. I know I can make one but between work and school I am very busy and tired, the couple of hours it would take to make one would be better spent on something else. However if I am unable to find what I need for sale I will make my own.

Thanks again.

[aussie_guy00000]

I know how exchange of heat works, and probbably better then you. This is not for two fluids either, I dont know what you assumed this was being used for, if you meant my chiller its a bit more complicated, it has 5 heat exchangers for various purposes.

I at no stage doubted your understanding of a heat exchanger, I was merely making an observation as to the physical size vs efficency of a hx, there's no need to stage a personal attack. Last time I checked, a fluid could be either a gas or a liquid, so unless you're passing a solid through your heat exchangers, i'm still under the assumption that that is what they're used for. Sorry if you've taken my opinion the wrong way.

[epion2985]

Dont appologise, I was just venting. Bad day. Sorry.

You got me on the linguistics there, I meant to say liquid not fluid. By the way I think plasma and the einstein bose condensate are also cosidered fluid.

Going to bed I have a killer headache from a physics lab. Night :)

[aussie_guy00000]

Lol, no worries, mate, hope you find what you're after :toast: .

[Marvin]

What about this ?
http://www.under-the-ice.com/product_info.php?cPath=30&products_id=72&osCsid=a3bd2e98cc33454f712d56bb3d781e12

[Xeon th MG Pony]

way too long for his needs. FYI I have asked this tons of times, does U.T.I. have a pay pal option or how are you able to pay?

[n00b 0f l337]

Yes it has paypal.

[Xeon th MG Pony]

Ah K ty

[Gray Mole]

Epion, keep in mind that it costs nothing to be kind. If you ask a question, then spit at someone who tries to help with an answer, you're not going to see much help in the future. Keep in mind that everyone's time is valuable, not just yours.

If you post your location, it would help in finding a supplier for you.

However, what I think you're looking for is likely a small Plate heat exchanger. I know that 'half size' versions are made at around 4-5" square, and 1.5" thick and up from there depending on the number of plates.

If you find the local supplier for 'Alfa Laval' or 'Swep' heat exchangers, or find out who does parts for Vaillant or other water boilers, they should be able to help you find what you need.

Plate heat exchangers are well known to be among the best, and while they are expensive, you may find where you are they are in your budget.

Cheers

Gray

[epion2985]

If you post your location, it would help in finding a supplier for you.

However, what I think you're looking for is likely a small Plate heat exchanger. I know that 'half size' versions are made at around 4-5" square, and 1.5" thick and up from there depending on the number of plates.

If you find the local supplier for 'Alfa Laval' or 'Swep' heat exchangers, or find out who does parts for Vaillant or other water boilers, they should be able to help you find what you need.

Plate heat exchangers are well known to be among the best, and while they are expensive, you may find where you are they are in your budget.

Cheers

Gray

US, CA, 95070. Although shiping it from uk or asia or anywhere elese is not a problem.

I have a plethora of plate ehat exchangers, and no thats not that I am looking for, not even the small square once. Not the right shape and orientation restrictions for the location its going to have to fit.

Thanks for the tip.

Yes plate hx are great, thats why I love using them :)

[[XC] mysticmerlin]

US, CA, 95070. Although shiping it from uk or asia or anywhere elese is not a problem.

I have a plethora of plate ehat exchangers, and no thats not that I am looking for, not even the small square once. Not the right shape and orientation restrictions for the location its going to have to fit.

Thanks for the tip.

Yes plate hx are great, thats why I love using them :)

So you can't just DIY one for what you need? If you can't buy it build it

[epion2985]

no time and very tired, rather buy one, but looks like I will have to make one.

[Xeon th MG Pony]

Some times it is the only option mate, I'm a poor pony so I have to custome make all most every thing lol.

[[486]]

same here, get real good with the lathe and milling machine though...

everyone here is because we arent paying other people to make cascades and stuff

[Xeon th MG Pony]

hehe, If I had a lath I'd be selling them, I have a design that I want to make but go figure no laths to use.

[epion2985]

']same here, get real good with the lathe and milling machine though...

everyone here is because we arent paying other people to make cascades and stuff

I have access to a machine shop just not enough time in the day. I make the systems myself but I see no glory or merit in making your parts. Its wasted time, nothing more. Its true sometimes people have alot of time as its worth little and little money, so making your parts is the logical choise, but thats not always the case.

Intellectual growth wise in a scientific proffesion you start at the bottom making nuts and blots and putting together what other people tell you, then you do final assembly and eventually you do the design and let the grunts worry about making and screwing on the nuts and lugs on.

[Xeon th MG Pony]

Or some times you have little time and no one makes what you need so you have to make the time to produce the part that you needed due to constrains that you engineered.

So you messed up by designing some thing so tightly that you can not use prefabricated parts, and thus will either A: Pay to have it custom made to your specs or B: Make it according to your specs, or C: correct your design to allot the space needed to fit in a standard part.


I try and design systems for high flexibility and functionality, this way any part can be put in, but for peros driven designs I find my self ofy having to manufacterur parts as the ones that would be needed don't exist and it would cost fare too much to have them made by a second party. So like I either pay or get working.

I'm sure some one on the forum here who has a lath and some time would machine you a custom "one run" piece for a fiar price.

[Nagaru]

Although I am new here I don't think it is appropriate to criticize someone else's design, especcially if he wasn't asking advice on it. Also when the first internal combustion engine was built I am sure many of the parts were hard to find and had to be custom made, but it was an xtremely important invention.

[Gray Mole]

I've just had to make a water HX for a slhx install.

http://www.picturehosting.com/images/GrayMole/dsc02983.jpg

http://www.picturehosting.com/images/GrayMole/dsc02985.jpg

http://www.picturehosting.com/images/GrayMole/dsc02984.jpg

http://www.picturehosting.com/images/GrayMole/dsc02986.jpg

I don't see it as being 'monkey work' just out of necessity you make what you need if a supplier can't be found for the configuration you need.

If you're not willing to do your own legwork to find a supplier, then you'll have to make it yourself. Otherwise, get someone who works in your machine shop to make it to your design and pay them accordingly.

Your tone is surprisingly 'elitist' and in a way it would seem that you're insulting the very people that you appear to need to do what you're asking for. Considering fabrication is a big part of what I do at work since a lot of the parts I need don't exist, I suppose I would fall into the 'Grunt' category. Thanks, you've made my day :rolleyes:

Cheers

Gray

[epion2985]

Or some times you have little time and no one makes what you need so you have to make the time to produce the part that you needed due to constrains that you engineered.

So you messed up by designing some thing so tightly that you can not use prefabricated parts, and thus will either A: Pay to have it custom made to your specs or B: Make it according to your specs, or C: correct your design to allot the space needed to fit in a standard part.


I try and design systems for high flexibility and functionality, this way any part can be put in, but for peros driven designs I find my self ofy having to manufacterur parts as the ones that would be needed don't exist and it would cost fare too much to have them made by a second party. So like I either pay or get working.

I'm sure some one on the forum here who has a lath and some time would machine you a custom "one run" piece for a fiar price.

Indeed. I was consearned with meeting sertain goals of the project so there is a price to pay. I think you guys got me all wrong, I dont have a problem with making it, its just if it can be avoided then thats for the better and if not oh well. Dont take it so seriously, its a crappy slhx :)


Although I am new here I don't think it is appropriate to criticize someone else's design, especcially if he wasn't asking advice on it. Also when the first internal combustion engine was built I am sure many of the parts were hard to find and had to be custom made, but it was an xtremely important invention.

lol dont worry about it. Criticizm is good, gives you something to think about, which either reaffirms your decisions or opens the door to some new ideas.



I've just had to make a water HX for a slhx install.

I don't see it as being 'monkey work' just out of necessity you make what you need if a supplier can't be found for the configuration you need.

If you're not willing to do your own legwork to find a supplier, then you'll have to make it yourself. Otherwise, get someone who works in your machine shop to make it to your design and pay them accordingly.

Your tone is surprisingly 'elitist' and in a way it would seem that you're insulting the very people that you appear to need to do what you're asking for. Considering fabrication is a big part of what I do at work since a lot of the parts I need don't exist, I suppose I would fall into the 'Grunt' category. Thanks, you've made my day :rolleyes:

Cheers

Gray


Thats perfect gray. Looks good. Thats what I am aiming for.

Like I said many times over and over I am willing to make it myself, i was just trying to avoid it. Its just a slhx, dont worry about it. heh if only I could spend the time I spend posting in this thread on it it would be done by now, unfortunatly I dont get to post from home much.

Well I am sorry if my tone offended you, if thats the case I appologise. However facts are facts and this is rather low end work. The reason for my sharp responce is because of the comment above I replyed to.

"everyone here is because we arent paying other people to make cascades and stuff"

I just made a counter argument. That is rather low end work and not something to be praised in comparison to design. And dont get offended I do very low end grunt work myself right now to get by, you do what you have to do and you do your job with pride and do it well. I believe in that. However that doesnt change the facts nor the tasks place. I know alot of people that can mill parts, I dont know quite as many that can run companies and design ground breaking technologies. I didnt mean to come off 'elitist', I was simply responding to the comment I felt was rather sharp itself.

[Gray Mole]

Wow.

Perhaps you aren't aware of it, or maybe it just didn't occur to you. This IS an elitist attitude.

I'm not going to get into a philisophical argument here, this isn't the forum for it. I'm just going to say that every job has it's place, whether design, manufacture, or maintenance. If you think that a person's job makes them better than someone else, or their job is more important simply because of it's title, then you're part of the problem that at one time made slavery possible. Congratulations.

Either do it yourself, or get someone to make it for you, but the time you've spent talking about it and telling people that you're too 'important' to do it yourself, you could have already done it.

Gray

[jinu117]

For obvious reason.