Timeline for Relationship between heat and temperature
Current License: CC BY-SA 4.0
5 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Dec 15, 2023 at 12:17 | comment | added | Chet Miller | You can recapture thermal energy to do work. All you need to do is allow the gas to expand against a slightly lower pressure. You just can't do work using a single thermal reservoir cyclically. | |
| Dec 15, 2023 at 9:47 | comment | added | naturallyInconsistent | "you can't recapture that thermal heat that is going to the air" NO! That is precisely the opposite of what I meant. Hot coffee is at a different temperature than air, and so the difference in temperature allows us to extract work, if we run a heat engine between them. That is how engines running on a hot cup works. One single temperature, means one single temperature. A room in which everything is already at one single temperature. Then the heat in it cannot be used. | |
| Dec 15, 2023 at 9:44 | comment | added | naturallyInconsistent | "Is it just a conceptual distinction we make to keep terminology clear?" Half and half. Heat flow is a transfer of energy that is automatic, statistical, only dependent upon temperature differences and we can only control it by changing the wall material. Work, on the other hand, is ordered, easily convertible and controllable, and so forth. Also, before thermodynamics became a proper theory, people did not know that heat is a form of energy at all. The first law is essentially stating that energy is conserved, and if you think you missed some, that missed part is heat. | |
| Dec 15, 2023 at 8:42 | comment | added | Ahmed Malik | Not to be pedantic, but the work you did to push the piston is essentially transferring energy to the system, right? So how is that transfer of energy via work different than heat? Is it just a conceptual distinction we make to be keep terminology clear? Also, when you say "one temperature to work with" do you mean like say a cup of hot coffee that is gradually cooling due to air exposure, so you can't recapture that thermal heat that is going to the air? | |
| Dec 15, 2023 at 5:20 | history | answered | naturallyInconsistent | CC BY-SA 4.0 |