Porsche P-80 2005, Руководство пользователя

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Air Conditioning Basics
Climate Control Systems Diagnosis & Repair
Page 1.3
Air Conditioning Overview
Air conditioning is the process of moving heat energy from
one place in the vehicle to another. Doing this raises or
lowers the temperature of the air in the vehicle interior.
The A/C system is a closed loop system in which a refrig-
erant is pumped by the compressor through the circuit
continuously. While it is being pumped, the refrigerant
changes state from liquid to gas and back again. The
refrigerant changes from liquid to gas in the evaporator as
it removes heat from the passenger compartment. Then
the refrigerant gas condenses back to liquid in the
condenser, giving off heat to ambient (outside) air. This is
a short description of how A/C works. These concepts will
be discussed in more detail in the next section.
Principles of Heat Transfer
There are four principles of heat and heat transfer that
apply to automotive heating, air conditioning and climate
control systems:
1. Heat always flows from hot to cold.
2. Materials absorb or give off large amounts of heat
when changing state.
3. The pressure of a liquid or gas varies with its tempera-
ture and the temperature of a liquid or gas varies with
its pressure.
4. The boiling point of a liquid varies with its pressure.