Question

Why is work done required to move heat from a cold reservoir to a hot reservoir?

Answer 1

How familiar are you with physics? School level, or university level?

Answer 2

I want to know how complex the answer should be

Answer 3

university level

Answer 4

I am not 100% certain because I have yet to take thermodynamics and heat transfer. You probably know by now that if you touch a hot object to a cold object, the heat from the hot object transfers to the cold object immediately. This is a direct statement from the 2nd Law of Thermodynamics: `Heat generally cannot flow spontaneously from a material at a lower temperature to a material at a higher temperature.` This is similar to how concentration flows from an area of high concentration to an area of low concentration. That is also the natural way that heat transfers. However, it takes work to take heat out of a cold system (ie refrigerator).
I recommend reading http://theory.uwinnipeg.ca/mod_tech/node79.html for the heat pump example and http://chemwiki.ucdavis.edu/Physical_Chemistry/Thermodynamics/Laws_of_Thermodynamics/Second_Law_of_Thermodynamics for supplementary reading

Answer 5

eg** not ie
Need to learn my latin better :P

Answer 6

I know that heat flows from a hot object to cold object so you mean we are doing something that is against its nature therefore work done must be applied, right?

Answer 7

Thanks

Answer 8

You are very welcome!