# What's like a heating element, but cold instead? **URL:** \ **Category:** Factual Questions\ **Created:** [April 3, 2018, 8:40pm UTC](https://boards.straightdope.com/t/whats-like-a-heating-element-but-cold-instead/811754 "2018-04-03T20:40:28Z")\ **Posts on this page:** 2\ **Page:** 2
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [April 5, 2018, 2:06pm UTC](https://boards.straightdope.com/t/whats-like-a-heating-element-but-cold-instead/811754/21 "2018-04-05T14:06:51Z")
[Authoritative cite](https://www.youtube.com/watch?v=Dc-m9dumEaw). ---
**Author:** ![Irishman](https://avatars.discourse-cdn.com/v4/letter/i/b487fb/32.png) [@Irishman](https://boards.straightdope.com/u/Irishman)\ **Post date:** [April 9, 2018, 2:22pm UTC](https://boards.straightdope.com/t/whats-like-a-heating-element-but-cold-instead/811754/22 "2018-04-09T14:22:13Z")
> [@Napier](#): > > A heating element, or a cartridge heater, is this solid piece with wires coming out of it, and when you put power into the wires, heat develops inside the solid piece and travels out to its environment. The thing is fairly ideal, having thin wires that don’t generate or move much heat themselves, so you could have long wires and it would be an ideal heat source out wherever you put it. I want something that does the opposite of that, and absorbs heat from its environment. A cooling element. > > A typical device for cooling has big pipes or ducts running to it, which are themselves a source of cold or heat. You can get a cooling effect in the location of your choice, but also a long line of heating or cooling effect that leads to the device. If you were watching with a thermal camera, not only would you see a very cold spot on the device, but you would also see the pipes as having their own special temperature. > > What would be an ideal device, as if it were exclusively generating the cold locally? > [snip] > > I don’t think this is thermodynamically impossible. If a device converted thermal energy directly into electricity, it would fit my requirement, but it would also be a free energy machine. I don’t mind expending energy to make this thing work, I just want the business end to do nothing but chill. I think this is the root of the problem. There’s a reason you can make an electric heater that uses small lines to put power in and get decent heat out, but can’t put cold out. That method of heating is not reversible. [Resistive heating](https://en.wikipedia.org/wiki/Joule_heating#Microscopic_description) > [@Chronos](#): > > But no matter what you do, if you want to cool off your element, you’re going to have to heat up something else, and to a greater degree. You have a choice of dumping this waste heat close to the thing you’re cooling, or transporting it (via pipes or something) to a more remote location. But you can’t avoid having to dump it somewhere. In this house, we obey the laws of thermodynamics. This. The trick you are looking for, I guess, is the “cleanest” way to transport that heat away. > [@EdelweissPirate](#): > > It sounds like the OP, while having a clear-eyed respect for the laws of thermodynamics, is looking for a source of “cold flux.” But as Chronos said, if you’re chilling something, you’re inevitably going to have to dump heat elsewhere. > > The OP mentioned chemical cooling via an endothermic reaction. If you only need “cold flux” for a little while, you could use liquid CO[sub]2[/sub] in a pressure vessel, slowly bleeding off the pressure. > [snip] > > If you could live with recharging a pressure vessel with liquid CO[sub]2[/sub], then you could get quite a bit of one-time phase-change cooling from that pressure vessel. You’re still dumping heat elsewhere, but you’re doing it elsewhere _in time_ (back when the CO[sub]2[/sub] was compressed and liquefied) rather than elsewhere _in space_ (as with a Peltier cooler, heat pipe, heat pump, etc.) This is an interesting approach to a solution. Basically, you want an ice box and a separate source of ice. Load ice in the box, get localized cooling. The cooling is done elsewhere and else_when_. Gas expansion may be more effective than a block of ice melting, but it’s the same principle. Compress the gas into a canister, transport canister to site, use vapor expansion to get localized cooling. Depends on how big you want to cool, how cold you want to get, how fast you want to cool, and how long you want it to work. [Previous page](https://boards.straightdope.com/t/whats-like-a-heating-element-but-cold-instead/811754.md?page=1)