VW Polo manuals

Volkswagen Polo Service & Repair Manual: 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:

Refrigerant Oil
Refrigerant oil mixes with the refrigerant (about 20 - 40%, depending on compressor type and amount of refrigerant) and circulates constantly in the system, lubricating the moving parts. Special synthetic refrigerant oils, for example, ...

Introduction
This chapter contains information on the following subjects:  → Operating ParkPilot    → Acoustic and optical ParkPilot signals at the rear of the vehicle The ParkPilot assists the driver when manoeuvring and parking. The ultrasound sensors in the rear bumper transmit and recei ...

Working on Airbag System
  WARNING When working on the airbag system (pyrotechnic components, Airbag Control Module -J234-, wiring), the ground cable must be disconnected with the ignition switched on. ...

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