Did you know that the word "refrigeration" simply means cooling, or heat removal? What a refrigerator means is essentially a compartment from which all heat is removed...

The heat is produced by the rapid vibration of the molecules, the temperature increasing with the increase in the speed of the vibrations. Whenever molecules in matter vibrate, heat is produced. If the molecular vibration is increased, the heat of the matter will increase and to produce more heat, energy must be applied. And if we want the molecular vibration or the separation between the molecules to decrease, we must dissipate the heat, for which energy must also be applied.

This principle of heat is observed in the refrigeration system when the compressor compresses the refrigerant gas inside its compression chamber and when it is expelled to the condenser, the gas is cooled by means of a current of water or air, then the heat generated by The energy applied during compression is transferred through the walls of the condenser and is carried by the water current or dissipated in the atmospheric air. Heat, like matter, is indestructible and can only be passed or transferred from one body to another.

When speaking of pressure, reference is made to the intensity or degree of pressure. And this can be defined as a force acting against something that offers resistance. Therefore, when it is said that the refrigerant in a system has a certain pressure, this refers to the force developed by the refrigerant against the walls of the tubes, the compressor, the condenser, or some part of the system that encloses it. .

This force, expressed in pounds of pressure per square inch, tells us that the refrigerant exerts said force or pressure intensity on each square inch of said surfaces, and this pressure intensity is measured with an instrument known as a manometer.

The first studies on the measurement of pressure were carried out by Galileo in 1637, who said that the weight of a body does not influence the speed of its fall and that an iron coin and a feather could reach the earth simultaneously if they were thrown in an empty space (without air).