Refrigerators and heat pumps

How do they work?

Expansion/compression of gases

Both of these devices take advantage of this behavior exemplified by gases:

Refrigeration cycle

Heat pump

Heating your house in winter...

Does it matter if the outside temperature is cooler than the inside temperature??

Air conditioner

[Writing] How could you arrange these expansions and compressions to air condition (cool) your house in the summer??

Reverse heat engine

The energy diagram looks like this...
...which looks like a heat engine in reverse.

But is this machine a heat engine?

Bring pressure ignitor to answer fridge question





A heat pump can be used to heat your house. Either instead of a furnace (mild climate) or in addition to a furnace (N. IN).

In the summer, you reverse the pumping of heat.. the cold temperature place is inside, and you pump heat to the outside (warmer). This is called "air conditioning"!

Such a device is *not* constrained to have an efficiency less than 1. The best devices currently on the market can move 5-6 units of heat from the cold place to the warm place for every 1 unit of electrical energy.

What is the very best a furnace can do with the chemical energy of natural gas when it heats your house? that is...

1 unit of chemical energy is converted to _____ units of heat energy inside your house?