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:

Long-Term Underbody Protection -D 314 D38 M2-, Bright Color
Definition: Long-Term Underbody Protection -D 314 D38 M2-, Bright Color Edition 02/2010 Product Description Long-Term Underbody Protection -D 314 D38 M2- is a bright, transpa ...

Refrigerant Circuit, Tracing Leaks, with Electronic Leak Detector -VAG1796
Note This repair manual describes different methods for detecting leaks in the refrigerant circuit. These methods have been tested and result in success when used correctly. If when searching for compressed air / Nit ...

Warning and indicator lamp
First read and observe the introductory information and safety warnings Lit up Possible cause Solution Dual clutch gearbox DSG® overheated. Do not drive on! Move the selector lever to position P and leave the gearbox ...