# Homework Help: Heat Engine Problem. Does the volume of a reservoir matter?

1. Sep 18, 2007

### fazerland

Okay, I thought that I got these two easy problems but for some reason I'm making them hard.

The first problem reads like this.
"A heat engine operates between a tank containing 1*10^3 m^3 of water and a river at a constant temperature of 10 degrees Celcius. If the temperature of the tank is initially 100 degrees Celsius, what is the maximum amount of work that the heat engine can perform?"

At first I thought that I would just find the efficiency of the engine by using the temperatures after converting them to degrees Kelvin and then use it to find the work. But that information about the volume is bothering me. Did the author put it for some reason in there? If so what would I use it for exactly and how?

The second problem is pretty similar except there are two tanks and both of them have the same volume.

If anyone knows how to deal with these problems and could respond I would be so grateful.

2. Sep 18, 2007

### Staff: Mentor

The amount of energy in the system is the mass of the tank times the delta-T.

The problem may want you to be considering the carnot efficiency of a heat engine that uses a source and sink at those temperatures. Remember when you calculate that, the temperature is not constant...

Btw, we have a homework help section...