HVAC Flashcards
What does the ozone layer do?
Acts as an invisible filter that protects from UV rays
What is the leading cause of ozone depletion?
CFC’s (chlorofluorocarbons)
What atoms make up the ozone?
Unstable three atom oxygen molecule
O3 (oxygen+oxygen+oxygen)
When was the Montreal protocol signed?
1987
What is global warming?
The build up of heat trapping gasses in the atmosphere.
When was the Kyoto protocol signed?
1997
What is CEPA and what does it say?
Canadian Environmental Protection Act says all CFC’s prohibited by 1996 and most HCFC’s phased out by 2020
What are two of the key provincial regulations for CFC’s?
Cannot release or permit release of ozone depleting substance into atmosphere
Cannot charge or permit charge of a/c system with CFC
What are the three laws of heat transfer?
Heat will flow from area of higher temp to lower temp
The greater the difference in temp, the faster it flows
Heat will continue to flow until temps are equal
What are three different ways heat can be transferred?
Conduction
Convection
Radiation
What is conduction
Transfer of heat from one object to another (solid)
What is convection?
Transfer of heat by fluid (liquid)
What is latent heat of vaporization?
Amount of heat required to change a liquid into a vapour without changing the temp of the vapour
What is latent heat?
The amount of heat required for a change in physical state
What is latent heat of condensation?
The amount of heat removal required to change a vapour into a liquid without changing the temp of the liquid
What 3 functions does the AC system perform?
Cools
Cleans
Dehumidify
What is Super Heat?
The temperature of gas above the liquid it came from
What is Sub Cooling?
The temperature below liquid from which it came
What refrigerants can be used in current AC systems?
R134a
R1234yf
What refrigerant is no longer permitted to be used in AC systems?
R12
What refrigerant could possibly be used in the future of AC systems and what is it made of?
R744
CO2
What are two ways to measure refrigerant in an AC system?
Weight
Temperature corrected volume
What are 3 types of refrigerant oils?
Mineral oil
PAG oil
POE oil