for the monthly assignment, I was given a topic about the information on refrigerators tho its a dumb topic but still I need some information other than the internet.
As long as you think a subject is "dumb",
you are not going to put much effort into learning about it,
so why are you in an Electronics-Forum expecting "information about
a simple household appliance that is covered in several thousand YouTube Videos ???
The principle of 'throttling' a high pressure, completely liquified substance through an orifice, (the expansion valve) to a lower pressure vapor, (essentially a gas with liquid particles), allows a significant temperature difference to be produced. At the beginning of the low temperature state, the cold vapor travels from one end of a heat exchanger coil, and absorbs heat from an external source, like the refrigerator compartment, as it proceeds through the coil, and after a time arrives back at the compressor inlet as a pure gas with no liquid particles.
... The initial cooling process is known as the Joule-Thomson Effect, and is more readily visualized in terms of a Temperature vs. Entropy chart for a substance such as Freon. A quick search for a simple example did not seem to be fruitful. ...Maybe there is something on YouTube though.