Volkswagen Polo Service & Repair Manual: Physical Principles

Volkswagen Polo Service & Repair Manual / Refrrigerant R134a Servicing / A/C System, General Information / A/C Technology Basic Principles / Physical Principles

The four known states of water also apply to air conditioning system refrigerants.

1 -	gaseous (invisible)

2 -

vapor

3 -

fluid

4 -

solid

Physical Principles

When water is heated in a vessel (heat absorption), water vapor can be seen to rise. If the vapor is further heated through heat absorption, the visible vapor turns into invisible gas. The process is reversible. The warmth is extracted from gaseous water, vapor forms first, then water and then ice.

A -	Heat absorption

B -	Heat emission

Physical Principles

Heat Transfer

Every substance consists of a mass of moving molecules. The fast moving molecules of a warmer substance give off some of their energy to the cooler and thus slower molecules. As a result, the molecular motion of the warmer substance slows down and that of the colder substance is accelerated. This process continues until the molecules of both substances are moving at the same speed. They are then at the same temperature and no further heat exchange takes place.

A/C Technology Basic Principles

...

Pressure and Boiling Point

The boiling point given in tables for a liquid is always referenced to an atmospheric pressure of 1 bar (14.5 psi). If the pressure acting on a fluid changes, its boi ...

Other materials:

Polyurethane Adhesive Sealant
Definition: Polyurethane Adhesive Sealant -AKD 476 KD5 05- Edition 04/2009 Product Description Polyurethane Adhesive Sealant -AKD 476 KD5 05- is a paste-like, one-part adhesi ...

Run-Flat Tire (PAX), Lettering On Side Wall
In contrast to conventional tires, other designations are found on the tire flanks of PAX tires. In this way, these tires can be allocated clearly. PAX Tires, Designations 245 ...

Corrugated Tube, Repairing
Special tools and workshop equipment required Hot Air Blower -VAS5179- or Hot Air Blower -VAG1416/- or Wiring Harness Repair Set - Hot Air Blower -VAS1978/14A- A ...