1. Introduction to Air Conditioning and Climate Control

2. Climate Control Systems are no longer considered to be a luxury item
Why?
Tests carried out by WHO (World Health Organisation) show that ones ability to concentrate are impaired by stress
The best temperature for the driver is between 20°C and 22°C

3. Control of the Vehicle Interior
Air Conditioning
Heating & Ventilation
Climate Control
Automatic Climate Control

4. Air Conditioning Principle of Operation
States of existence
Water can exist in 3 different states depending on its temperature.
Below 0°C – Solid(Ice)
0°C - 100°C – Liquid(Water)
Above 100°C – Gas(Steam)

5. Sensible Heat
As heat is applied to water, increases in temperature can be measured using a thermometer.
As the influence of the heat can be measured, it is referred to as ‘SENSIBLE HEAT’

6. Latent / Hidden Heat
When water reaches 100°C it boils and starts to change state from liquid to a gas.
To ensure this change of state occurs, heat still has to be applied although the temperature of the water does not increase
To enable the change of state to take place, energy is required
This energy / heat is known as ‘LATENT’ or ‘HIDDEN HEAT’

7. Using LATENT Heat
If a suitable gas / Refrigerant is compressed into a liquid and then forced through a restricted orifice
It changes back into a gaseous state
In order for it to be in a gaseous state energy is required
This energy is absorbed from the surroundings, hence cooling them

8. Refrigerants Refrigerants must have a low boiling point
In normal atmospheric conditions it exists as a gas
Traditionally a gas known as Freon12 (R12) has been used
This gas is a chlorinated hydrocarbon (CFC) and harmful to the environment

9. R 134A This is now the most common refrigerant used
It replaced R12 in the early 1990’s, as R12 is only permitted to be used to top up older vehicles
R134A destroys a fraction of the Ozone compared to R12

10. HEALTH & SAFETY
Only suitably trained personnel should attempt to repair an Air conditioning System
Protective gloves MUST be worn to prevent possible Frostbite burns, as escaping refrigerant will be approx. –26 degrees Celsius

11. HEALTH & SAFETY
Due to the possibility of a leak of Refrigerant under extreme pressure eye protection MUST be worn

12. HEALTH & SAFETY
All Refrigerants are classified as TOXIC, it is therefore illegal to dispose of them without a license
If R134A is allowed to occupy a non ventilated room, there is a severe risk of suffocation

13. HEALTH & SAFETY
R134A refrigerant is not highly flammable but if it were to be exposed to high temperatures, the resulting Toxic gas would be highly dangerous.

14. Component Layout On switch Relief Valve Radiator fan Pressure sensor
Coolant temp. sensor
Fan thermo switch
Evaporator temp. sensor
Fan
Engine ECU
Magnetic clutch

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