Here’s a technical document about a Thermoelectric Contact Cooler/Freezer from NASA Tech Briefs.
You may be asked to register to get the document, but it is free. If necessary, enter the site here, click on “Technical Support Packages”, then “Machinery/Automation.” The file you want is in the November 2001 issue, MSC22631.
Briefly,
So, RAWisSYDNEY, let me know how it works on popsicles. I could use one in my kitchen.
You should check this out, to see if it will meet your requirements. Just look up Magnetic cooling on Google. I only know about this because one of my canoing buddies is the Carl Zimm mentioned in the article. He was given a bit of space in Scientific American a couple years ago.
http://www.external.ameslab.gov/news/release/cool.html
I don’t know exactly what he is doing now though.
Another effect in microwave ovens is that most models have “hot spots” and “cold spots” due to standing wave patterns. It’s conceivable that a hot spot might happen to be right in the center of a potato, so that the middle actually does heat faster than the outside.
For exotic methods like laser and magnetic cooling, remember that these are usually only applied to systems of a few atoms or so. I think that laser cooling is only effective on volumes of the order of a cubic wavelength or smaller… Get out of that region, and the laser is heating just like you’d expect.
Just a gentle reminder to anyone who does obtain some LN[sub]2[/sub] (Liquid Nitrogen).
Make sure that whatever container you pour it into is not sealed afterwards. This is a splendid method for making a rather powerful explosive device. Even when stored in a vacuum flask (i.e., thermos or Dewar), liquid nitrogen still evolves into the gas phase. If you leave no exit path for this gaseous byproduct, you have just created a bomb.
A really fun experiment to perform with liquid nitrogen is what I call the “liquid dry ice hockey puck” demonstration. Just as a puck of dry ice will demonstrate near-frictionless characteristics as it glides around on its sublimating gas envelope, so will liquid nitrogen exhibit similar tendencies.
Place 10cc of LN[sub]2[/sub] in a pan and swirl it into a nice whirlpool. Come back in a few minutes and the liquid will still be swirling in the pan. It too will demonstrate the fiction reduction of the dry ice puck. You can also use it to freeze alcohol, turn grapes into marbles and make a rose shatter like glass. My father would bring home a thermos of the stuff from the Lawrence Berkeley Laboratory every once in a while when we were kids. It is also commonly used in cryogenic cooling or “cryostats” for pumping water vapor out of the high vacuum systems used in semiconductor fabrication. I have worked with many Dewars (as in Dewar’s Scotch Whisky) of the stuff in my time.
As to the OP, energy removal is a far more difficult proposition than energy addition.
While on the topic of LN2 and safety: make sure you store the tank in a well ventilated area! If the tank has a safety valve, as it must, nitrogen gas escapes slowly from it and can fill up a room, displacing all oxygen. If you step in there you won’t feel any discomfort - you’ll just pass out and die. Your body can’t detect a lack of oxygen, unless it’s accompanied by an over-abundance of CO2.
No. The frequency of the microwaves is nowhere near the frequency of vibration of the water molecules.
I recall reading in an old issue of Omni magazine that you could cool something down real fast by spraying it with a fire extinguisher. I’ve never actually tried it.
Anthracite: WordReference.com says
I could go look it up in my Honking Big Ass[sup]TM[/sup] dictionary, but that’s buried somewhere. A little help? 
http://www.dictionary.com/cgi-bin/dict.pl?term=anisotropy
Basically, like it says, it means exhibiting different physical characteristics when measured/tested in different axes. Like carbon fibers do.
I clicked both, on both address.com said “Address Not Found”. That’s ok tho, your definition is good enough. Thank for draining a…moderate amount from the vast pool that is my ignorance :D.
Just to chime in on the Industrial refrigeration discussion… Liquid Nitrogen is used mostly do put a shell on the IQF product, so they don’t stick together. In the vast majority of applications I see, after they have their surface frozen with the Nitrogen they go into a standard mechanical freezer, usually a spiral cooler or something, and the rest of the freezing is done there. Basically it’s a cost thing. Per unit of cooling at most common industrial temperatures Liquid Nitrogen costs 5 to 10 times as much as mechanical cooling. Also, unless a product needs a surface “crust”, like good shrimp and strawberries, they tend to skip the nitrogen all together, or just use it to increase shelf life of non-refrigerated perishables like potato chips. Nitrogen and CO2 systems are fairly cheap to install, but their high operating costs were causing them to be gradually faded out. The massive increase in electrical costs in CA have caused them to be far more rapidly faded out. I don’t think there are more than a handfull of companies that still have even partial nitrogen freezing systems, and some of those limit the use to speciallity products like frozen rubarb. Big market for that.
Fast freezing is expensive anyway you look at it. It would generally be far more cost effective to greatly increase your refrigerated storage space. It doesn’t work well with heated products because they overcook or spoil if kept hot too long, like stuff in hot trays or under heat lamps. Cooling stuff actually increases its life usually, so you just store more and there’s no problem.
What we need is a macrowave.
Where a microwave excites the molecules in water and fat to heat it, a macrowave would do the reverse, calm down, or chill out, the water and fat molecules, causing it to cool down rapidly.
It’s all radio waves.
There are some stations out here that are rather stultifying that I will experiment with to attempt to rapidly chill items. However, these radio waves may leave a bad taste.
If you’re chilling a chicken breast or a jelly donut and you try the vacuum method (already soundly disrecommended several times here), you will end up with tepid but dehydrated food. The vacuum would lower the boiling point of any moisture in the object and it would evaporate out.
Of course, if you’re just trying to chill a beer, no problem. Except that it won’t get cold.
Anisotropy refers to a physical property or action that does not occur in all planes while taking place. It is a term commonly used in semiconductor processing.
The opposite of anisotropy is isotropy. As an example, an isostropic etchant will attack and remove material in all axes at once. A groove that is being isotropically etched into a flat surface will deepen into a “vee” shaped trench with walls that have a 45º angle. If the etch begins from a single point the cavity produced would be conical in shape. The leading edge of the area of removal expands in all directions equally.
With an anisotropic etch (of the type prefered in semiconductor processing), the groove would be etched deeper and deeper, yet still maintain vertical walls. Methods such as ion milling and reactive ion etching are used to produce these etch profiles and such processes are critical for successful fabrication of solid state devices. Current production of DRAM (Dynamic Random Access Memory) circuits require the creation of “trench capacitors”. These charge storage devices, if flattened out into a planar shape would consume vast amounts of real estate on the circuit’s surface area with their large “footprint”. To avoid such out of scale features a deep trench is cut down into the silicon wafer and the interior is lined with alternating layers of conductive blanket tungsten, a nonconductive dielectric film layer and then another layer of tungsten. This sandwich is deposited in a trench that has an aspect ratio of 10:1 and up to 17:1. To cut such deep vertical trench capacitors relies heavily upon anisotropic etching methods.
I hope this clears things up.
I’m not going to read all the posts, so I apologize if someone has already posted this.
When I used to work on my car back in the 70s I had a product that was an aerosol that you squirted on tough bolts to loosen them by freezing them. You can do something similar with canned air for cleaing computers simply by turning it upside down before spraying it. Don’t do this to people, or they end up like Wesley Snipes in Demolition Man