What is heat & how did it works to the refrigeration cycle?
Answer:
Heat/energy is the ability to do work (standard physics definition, sorry). In a refrigeration cycle, heat is absorbed from the inside of the refrigerator (the cool side) and then expelled outside of the refrigerator (the hot side). Heat is transferred via a liquid coolant that is repeatedly evaporated (during which it absorbs heat) and then condensed (during which it gives off heat).
The coolant is fed via a pump or motor to the cool side of the cycle (again, this is the inside of the refrigerator). The coolant evaporates and in doing so absorbs a bunch of heat (heat of vaporization), thus cooling the inside of the refrigerator.
The expanded coolant then flows to the hot side of the refrigerator where a compressor increases the coolant's pressure. The coolant condenses as a result, releasing heat (heat of condensation) in the process. This is why the back of a refrigerator (where the coils are) is usually warm. The liquid coolant then flows back to the pump and is fed back into the cycle so that it can evaporate again.
That is a simplified description of how the refrigeration cycle works.
fridgeration works roughly like this
compress some freon, that makes it hotter, then let it expand, that makes cold, then blow air past the fins to get that cold, then compress it again, and so on, repaet
You need to understand the law of thermodynamics:
http://en.wikipedia.org/wiki/first_law_o... (and the second Law of thermodynamics)
and how a refrigerator works:
http://en.wikipedia.org/wiki/heat_pump_a...
1...*...Heat energy is removed from the inside and the contents of a fridge by absorption into a liquid/vapour refrigerant.
*...This Vaporises the liquid refrigerant by adding Latent heat to it. It also adds Sensible Heat to warm up the Vapour.
*...This heat now goes with the Vapour to a Compressor that adds Pressure to the refrigerant and also adds more heat by Compression.
*...ALL of the heat in the compressed vapour is now removed in the Cooler/Condenser coils behind the fridge...
*...Sensible Heat of Cooling to ambient temperature, and, Latent Heat of Condensation is also removed to condense the refrigerant.
*...All of this heat goes into the atmosphere of the room containing the fridge.
*...The cool, high pressure, refrigerant liquid now goes to an Expansion Valve where the pressure is decreased considerably.
*...This causes an increase in the volume and some of the liquid vaporises and the liquid gives up Sensible Heat in the form of Latent Heat of Vaporisation to the vapour.
*...The liquid refrigerant therefore cools down greatly to near the boiling point of the refrigerant, (Joules-Thompson Effect).
*...The cold refigerant liquid and vapour pass through the 'Cold Box' of the fridge where it is fully re-vaporised and heated by absorbing Latent and Sensible Heat from the fridge interior and contents...completing the cycle.
..Return to 1..at the top .. the cycle repeats continuously until the fridge thermostat senses the temperature of the refrigerant leaving the cold box is equal to its setting and, shuts off the motor and compressor until the system warms up slightly and re-starts.
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