Installing a Thermoelectric Peltier Refrigeration Cooling System


bob25

Recommended Posts

I am looking for a cooling kit for my cabinet.

I came accross this kit on ebay.

will it work as a cooling system for a 1.9M height / 70cm width / 50cm depth cabinet?

Thinking of installing it on the back of the cabinet at the bottom and include some fans to help the Circulation.

http://www.ebay.com/itm/Thermoelectric-Peltier-Refrigeration-Cooling-System-Kit-Cooler-Double-Fan-DIY-/141690352652?hash=item20fd67340c:g:SncAAOSwm8VUvMG2

I was thinking on connecting it to a Temp controller like this:

http://www.ebay.com/itm/220V-WH8040-Digital-Temperature-Controller-Peltier-thermoelectric-New-/350892707754?hash=item51b2d5cfaa:g:NvoAAOxybetR~KZV

Link to comment
Share on other sites

I was looking at something similar for mine. I have an Aristocrat from Bob never got the cooling feature with it. Anyways I asked bob about installing one later and he said the cabinet should have been be set up to keep it cool first, meaning different insulation, thicker wood backing? anyways sorry  I was no help I will follow the thread to see how it works out for you.  

Link to comment
Share on other sites

In all honesty, I cannot imagine a $26 eBay peltier will be worth your time or the expense to install it properly. I'll assume your cabinet is not insulated (like actual insulation built into the cabinet). If so, then this peltier will more than likely blow itself out trying to cool your cabinet.

If you're serious about adding cooling to your cabinet with a peltier, I'd suggest checking with Bob Staebell to see what an industrial grade pelter would cost and how you would go about retrofitting it into your cabinet. 

That eBay seller has a terrible feedback score, btw.

  • Like 1
Link to comment
Share on other sites

Thanks for your help.

my cabinet is not insulated. I visited Bob Staebell site. he has electronic humidifier. didn'nt see electronic coolers for sale.

In the summer it can get in here to 30C +.

I have AC but when Im at work its turned of.

Link to comment
Share on other sites

... so, in summer, when the TE cooler gets below the dew point to cool, the water drips on the fan, and the fan flings water all over the cigars, who do you call, a plumber? Sorry folks, I love this stuff, but one never gets to see the reality of summer conditions on most of these projects. I did notice that the guy snatched the hygrometer from one of the shelves before you could see that it did not match the other areas. -LOL

Folks, when it works people will who can prove it will prove it and will post a data log of it working. I am not trashing a guys work here, but this is a problem with the internet. You get a snippet and an opinion that is formed from 10 days worth of testing. And on the 91st day, when it all melts down you don't get a further report...

Bad data never seems to decay on the net... That is another story!

 

This does give me some ideas however and I think I am gonna' buy one of these cheapie TE units. Well, first I can prove that TE units dehydrate, another internet myth that they do not.

But here is an idea, something that I know I can build.

A lot of you guys like your ice-chest coolers. You need something with insulation. I fit one of these coolers with a number of sensors that report back to a CPU a few thousand times a second. I modulate the voltage on the plate so that it keeps a healthy distance from the dew point at a given setting. You put the whole shebang in and ice chest, you get a template to router cut the profile in the cooler. The housing that is made slips in the open space and is flanged to fit.

So here is how it works. The CPU is set for your desired temp, say 70F. The dew point of 70F and say 65rH is know (57.76 at sea level) so 60F is plugged into the CPU. The CPU keeps the coil (sorry compressor cooler user here) cold plate at 60F constantly when cooling. The fans run full and you modulate the voltage to the cold plate!

Now this is a poor way to cool, because the cooling when the system is opened, or if the ambient goes too high will never work or recover. BUT, if the ambient is cool enough, then you will eventually get back to the 70F mark where you want it to be. I doubt the BTU value at a cold plate limit of 60F will ever be much, this is a tough row to hoe, but you can get there with a  small ambient delta over a long period of time. Calcs need to be done, but I am not going to do them!

You need a drain! Why, well, when you open the box and it happens to be 80rH outside and you get an air exchange the dew point changes and the programmed response of the cooling system will never know. The system won't know because it does not have a reference rH sensor. Well, that is okay because you are using passive rH buffers here and when the rH runs up and the dew point rises, the cooling system will then actually scrub the unwanted rH out of the box and drain it outside. You get a means then to dehydrate back to your desired setting, actually by accident!

Hmmm... I might have to build one of these to see if the theory is sound...  The next million dollar idea founded on FoH...

Cheers people!

Oh, and to the OP, sorry! What is the BTU on the unit and what is the delta and heat transfer needs of your humidor? Without that data you are spinning your wheels and wasting your time on this project. No offense intended.

-Piggy

Link to comment
Share on other sites

7 hours ago, PigFish said:

What is the BTU on the unit and what is the delta and heat transfer needs of your humidor?

I tried calculating the BTU on the unit...the result was approximately 342 BTU/hour or 100 watt.

Dont know what that means...

As for the others...I have no idea how to calculate them. can you help?

Basically, I need to lower the Temp in the unit during the summer by 8C-10C

Link to comment
Share on other sites

11 hours ago, bob25 said:

I tried calculating the BTU on the unit...the result was approximately 342 BTU/hour or 100 watt.

Dont know what that means...

As for the others...I have no idea how to calculate them. can you help?

Basically, I need to lower the Temp in the unit during the summer by 8C-10C

This is not really my expertise and I have not had the need to do energy calculations in a very long time.

I don't know that the cooling capacity of the cooler can be derived by conversion of watts to BTU. It may need to be empirically derived for a family of these coolers so that a loss coefficient can be derived. There are likely more and less efficient TE devices. The persons making the device should have this data. At what ratio the power consumed equates to thermal heating or cooling is not known to me.

That is only part of the problem. The rest resides in the surface area, the material make up, the heat generated in the interior, the insulation rating of surfaces (if any), even the color of the exterior.... Then there is the target interior temperature, the delta it needs to overcome and a generous 'fudge' factor.

So you would need the tables or R values for each surface facing outside the cooler. The lid and the base my have totally different calculations, a known R rating for each surface and generate a number per degree delta. You will need fans and electrical equipment to move that air/water around, and those items create heat... Oh, and by the way, the thermal characteristics of air changes with water content. As water is more difficult to heat than dry air.... The water that will condense and freeze on the 'cooler' will reduce its efficiency to cool air alone.

Lets say one of my Chinese made wine coolers consumes 600 watts when running. It has dual pane glass, and 1.5 in of insulation. If even 300 watts of the rated power consumption is converted to cooling capacity for 5.6 cuft of interior space, what does that get you? It would tell you that even a relatively small, well sealed and insulated space may require 1000 BTU of cooling... and I am just guessing! If you said the appliance really pulls 600 watts, and is 80% efficient, that would mean that the BTU requirement was 1600+ BTU.

So you have to look objectively at your project. If it is not insulated, and you have no plans to insulate it... give it up! If it has single glass... same, give it up!

Since the product is made of wood (I assume) you can likely find some tables on the internet designed for home building. You can research that as well as I can so you don't need me! Do a search for R value of plywood.

This might help you familiarize yourself with the process. This is the Panel Heating and Cooling section of the ASHRAE handbook (2008 edition). It is overkill... but you might get the idea.

S08_06IP.pdf

Good luck on the project!

Link to comment
Share on other sites

... okay, this is why you don't want me doing your calcs! Just went and looked at one of my coolers and they are rated at 130 Watts. I knew there was something fishy in may analysis...! -LOL Why I have 600 watts on the brain is beyond me.

I quit!!! Lets page @Fugu, he is always correcting my math anyway!!! -LOL

You want someone competent doing your calcs...:idea::innocent:

-the Pig

Link to comment
Share on other sites

  • 3 weeks later...
... okay, this is why you don't want me doing your calcs! Just went and looked at one of my coolers and they are rated at 130 Watts. I knew there was something fishy in may analysis...! -LOL Why I have 600 watts on the brain is beyond me.

 

I quit!!! Lets page @Fugu, he is always correcting my math anyway!!! -LOL

 

You want someone competent doing your calcs...:idea::innocent:

 

-the Pig

 

 

Here is some data on my AW-281E (I am on the US power grid)

 

c73e04f2cfca88659ce6b78051776a21.png

 

5121683bd975b515d32fdc375a779f8b.png

 

It is keeping my cigars 13 degrees F below the ambient room temperature.

 

Here is a week's worth of RH and Temp from the cigars point of view

 

1bd234dfff04823837bb757d42f41b90.png

Link to comment
Share on other sites

  • 3 weeks later...
Just now, bob25 said:

I decided to buy a 28 bottles wine cooler instaed.

Works great! Saved me a lot of work...

I was going to piggy back off yours if you did. Did you ever find a good working model?

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.

Community Software by Invision Power Services, Inc.