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Cooling Technology

07/13/2017 1:02 PM

Several questions for the Engineers and those in direct or related industries:

A. What is the trade or technical name for the " nano material " employed in a, Evapolar ? and can this material be purchased from a third part supplier ? ( name, location ).

B. What is the best possible pulse width modulation ( speed ? ) to minimize the solder and mechanical degradation in and when using a peltier module ?

C. Any information on Websites, white papers, pdf files, government or private groups doing research on using peltier modules in liquid heat exchangers ?

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#1

Re: Cooling Technology

07/13/2017 2:02 PM

A. This is basically a small swamp cooler. Bad idea when totally indoors.

B. IHNI - sorry

C. LMGTFY - Let me Google that for you.... you know what to do next.

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Guru

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#3
In reply to #1

Re: Cooling Technology

07/13/2017 3:40 PM

James,

Evapolar claims it's the world's first micro air conditioner. On their website they repeatedly mention how bad cellulose pads are and that led to their decision to use " nano material " ( borrowed from Russian military technology )

The PWM came from cool@tetech.com website. In the FAQ section they explain this but don't show an example of an application or links to more information.

Yes, I have googled these and others but I thought I would get some ideas from those who might have a spoon in the pot.

Thanks for taking time out from golfing, chopping up wood or rounding up little doggies.

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#9
In reply to #3

Re: Cooling Technology

07/13/2017 4:53 PM

They have me on the work-go-round from now on, less time, more filling.

Even if this mini-A/C unit is not evaporative, it is either Peltier, or it is VCC cooling, and in any case, even evaporative, the waste heat has to go somewhere.

If it goes to evaporating water (does not matter how the water evaporates or what technology is used to evaporate it) no such device can lower the temperature even to the wet bulb, and certainly not to the dew point, although close enough for government work even with stupid cellulose pads.

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#2

Re: Cooling Technology

07/13/2017 3:39 PM
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#4

Re: Cooling Technology

07/13/2017 4:25 PM

Ask Mork from Ork--he's all about nano.

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#5
In reply to #4

Re: Cooling Technology

07/13/2017 4:27 PM

Or ask a real orca, such as Namu.

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#6

Re: Cooling Technology

07/13/2017 4:29 PM

Book him, Nano.

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#10
In reply to #6

Re: Cooling Technology

07/13/2017 4:56 PM

Sad. NO wonder you wore a bag over your head.

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#7

Re: Cooling Technology

07/13/2017 4:36 PM

When driving a Peltier device, it is best to feed it with a steady current to minimize ohmic heating. The amount of heat pumped is proportional to current, ohmic heating to the square of current. A higher frequency pwm will allow you to use smaller caps to filter it.

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#11
In reply to #7

Re: Cooling Technology

07/13/2017 6:17 PM

Rixter:

From what I understand, in reading the information, is that stabilization of the current, sans voltage ripples, is preferred, to have a constant in the pwm. Am I understanding this correctly ?

The idea of a peltier device to cool water using a heat exchanger came from my observation of people putting blocks of ice in to an evaporative cooler water basin to lower the supply / make up water temperature.

I was wondering if anyone was working on peltier device heat exchanger toward this end.

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#12
In reply to #11

Re: Cooling Technology

07/13/2017 7:34 PM

"I was wondering if anyone was working on peltier device heat exchanger toward this end."

I doubt it. Peltiers are power hogs. Extremely inefficient.

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#13
In reply to #12

Re: Cooling Technology

07/13/2017 9:22 PM

That's the problem they are not efficient, especially when there is a better option that is much more efficient.....

..."Above the cooling capacity range of 100W, the vapor compression based system will be far superior to the thermoelectric systems: ¼ to ½ the weight and volume, and 1/3 to ½ the power consumption compared to the thermoelectric systems."...

http://www.appliancedesign.com/articles/93330-miniature-bldc-rotary-refrigeration-compressors

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#14
In reply to #13

Re: Cooling Technology

07/14/2017 9:03 AM

There is nothing new under the sun, just miniaturization of the larger things under the sun. LOL

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#15
In reply to #12

Re: Cooling Technology

07/14/2017 9:12 AM

What about Super Large Magnetostrictive Effect Devices? I thought this was going to be the "new" thing in refrigeration.

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#8

Re: Cooling Technology

07/13/2017 4:42 PM

A. Never heard of it.

B. This article suggests 300-to-3000 Hz range. It also has a link back to TE Technology Inc. (Normal disclosure - no affiliation) that has a lot of useful information.

C. Besides the info above, you might checkout Tellurex, and other manufacturers. Some of them have some pretty good white papers on their sites.

Good luck

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#16

Re: Cooling Technology

07/15/2017 10:59 AM

Just guessing, but I suspect that the maximum life of a TE cooler will be obtained when it is driven by an analog signal slower than a thermal time constant of the cooler. When faster response times are required, we tend to use JT coolers.

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