Home | Science | Why is the Sky Dark at Night? |     Share This Page

Why is the Sky Dark at Night?
A discussion of Olbers' Paradox and related issues

Copright © 1996 - 2006, P. Lutus

(double-click any word to see its definition)

The Heat Pump

Refrigerators and air conditioners are examples of heat pumps. There are now even devices called "heat pumps," avoiding all pretense, whose task is to heat or cool a house depending on the season. All these devices take advantage of the relationship between pressure and temperature in a gas.

Here is an idealized heat pump. If you point your mouse at the various elements in the image at the right, explanatory notes will appear at the bottom of the screen.

Heat pumps in the real world around us use special refrigerants that change from a gas to a liquid as they move through the system. This makes the heat pump more efficient, but the basic principles are the same.
 

Home | Science | Why is the Sky Dark at Night? |     Share This Page