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 ...

Changing bulbs in the front bumper
Fig. 182 In the front bumper, right-hand side: removing the cover and headlight Fig. 183 In the front bumper, right-hand side: removing the cover and headlight First read and observe the introductory information and safety warnings The actions should onl ...

Preserving Wax (Spray Can)
Definition: Preserving Wax -D 308 SP5 A1- Edition 04/2009 Product Description The Preserving Wax -D 308 SP5 A1- provides optimal corrosion protection for areas in the body th ...