HVAC: Heating & Air-conditioning: HVAC basic principles

HVAC legislation	In most countries, any person who services an air conditioning system must be separately accredited to comply with local environmental protection legislation, or under close supervision of an accredited person.
Vehicle heating & ventilation systems	To improve passenger comfort and safety, fresh air is drawn from outside ducts and directed to the passenger compartment. Incoming air can be heated by passing over a small heating core connected to the engine's cooling system.
Basic air-conditioning principles	Heat transfer can take place by one of three methods, conduction, convection and radiation.
Air-conditioning capacity	Latent heat is the amount of heat required to be added to a substance or removed from a substance to bring about a change of state.
Air-conditioning refrigerant	The refrigerant removes heat from the vehicle interior and transfers it to the outside air in a continuous cycle of vaporization and condensation.
Humidity	Reducing the temperature of the air also reduces its humidity. Cold air will not hold as much water vapor as warm air.

Topic	Summary