What kind of processes are there using which it is possible to change the temperature of a material as fast as possible.

You are allowed to use any material you want.

Constraints -

  1. It should remain in the same state of matter (solid/liquid/gas) within the temperature range of 5 to 65 degrees celsius.

  2. The material should be able to suddenly reverse the direction of temperature change - so if i want to reduce its temperature at a given rate and then suddenly increase its temperature after a short period (generally <1s) there should be least resistance to reversal of the direction of temperature change.

Bonus points for minimising the amount of energy needed to do the above per unit mass, per unit temperature.

Bonus points if you can think of a liquid to do the above.

  • $\begingroup$ How rapid and for what size chunk of matter? The problem is woefully vague at this moment. If you want to quench something, liquid nitrogen will work and electric heating. If you can do it slightly slower I would use a Peltier element or a heated cold gas stream. $\endgroup$ – CuriousOne Dec 23 '15 at 7:18
  • $\begingroup$ Quite rapid - several degrees celsius in less than a second. The chunk of matter is small - less than 50 grams. If you can provide for smaller sizes - less than 10 grams even, I could use it for what I want by accordingly designing the system. $\endgroup$ – Yuganka Sharan Dec 23 '15 at 7:20
  • $\begingroup$ A Peltier element can do that for a sufficiently small sample (maybe up to a couple ten grams of material). More rapid cooling can be achieved with high velocity gas streams, but that will take a lot more power for the heater, of course. The biggest challenge is the heat conduction in the material itself. In metals it can be rapid, but many solids will show significantly slower heat conduction than you would want if they are thicker than a mm or so. $\endgroup$ – CuriousOne Dec 23 '15 at 7:22
  • $\begingroup$ I don't think I will be able to use gas streams in my case. Say i give you an arbitrary source of power, and you are free to do anything you want to change the temperature of the material (which also you can choose), and also you can keep its mass small, even less than 10 grams (so less power is needed). Would your answer change in that case? Also, can peltier elements rapidly reverse the direction of their temperature change? $\endgroup$ – Yuganka Sharan Dec 23 '15 at 7:34
  • $\begingroup$ My answer would stay the same. I have frozen small amounts (1 ml) of room temperature water with Peltier elements in a few seconds just for fun with no optimization, whatsoever. They are completely reversible and their thermal mass is small enough to achieve the kind of cooling/heating ramps that you are asking for. If you don't want to use gas, you could also use two pressurized water reservoirs and a simple valve. That, too, should get the job done. Since water has a fairly high heat capacity (4.2J/gK), flow rates of <100ml/s should be enough to get the heating/cooling that you want. $\endgroup$ – CuriousOne Dec 23 '15 at 7:40

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