# Heat from an infinite reservoir?

Dawei
Hello,

For a refrigerator, if a low temperature (TL) reservoir has infinite heat capacity, what is the heat QL that is coming from it?

I have W = Qh - QL and I believe I know what Qh is, but I need a better way to express QL, something involving TL, TH, and/or W.

I know QL = CpdT, but obviously that does not help in this case...

## Answers and Replies

JerryClower
Can you please elaborate on your question more?

Dawei
Hm, I guess it wasn't quite straightforward. It's just a simple refrigerator, pumping heat from a low temperature reservoir to a high temperature reservoir by inputting work W.

The low temperature reservoir has infinite heat capacity, the high temperature reservoir does not.

I'm trying to find an equation for the heat flowing from the low temperature reservoir.

Mentor
Both reservoirs are assumed to have infinite heat capacity. That's the only way to achieve a steady-state with a constant temperature for each.

....so I'm not clear on what the issue is here either.

Dawei
Both reservoirs are assumed to have infinite heat capacity. That's the only way to achieve a steady-state with a constant temperature for each.

The other reservoir, the hot one, does not have infinite heat capacity, it is maintaining a constant temperature because it is losing heat at the same rate that it is coming in from the refrigerator.

Mentor
The other reservoir, the hot one, does not have infinite heat capacity, it is maintaining a constant temperature because it is losing heat at the same rate that it is coming in from the refrigerator.
In that case, it's an open system - and the cold reservoir would work the same way.

JerryClower
I'm trying to find an equation for the heat flowing from the low temperature reservoir.

Let H represent the hot temperature energy and L represent the low temperature energy.

H=L

eggomaniac
What is the 'infinite capacity', a nuclear power plant?
Is the evaporation and condensation of the precipitation cycle not a simpler model for the formula?
The earth supplies the infinite heat, the atmosphere the infinite cooling and it rains all the time.
[However none of the above is truly 'infinite'.]