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

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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:

Decorative Trims, Replacing, Bonded Decorative Trims
Special tools and workshop equipment required Cartridge Gun -VAG1628- Trim Removal Wedge -3409- Wiring Harness Repair Set - Hot Air Blower -VAS1978/14A- Materials ...

Opening or closing the windows electrically
Fig. 32 In the driver door: buttons for the front and rear electric windows with one-touch opening and closing. First read and observe the introductory information and safety warnings Buttons in the driver door with one-touch opening and closing Key for : Buttons for the windows in the f ...

Service interval display
First read and observe the introductory information and safety warnings The service display is shown on the instrument cluster or . Service schedules at Volkswagen are divided into two categories, oil change service and inspections. The service interval display provides information on the n ...