Refrigeration Safety 080305a Flashcards
A liquid cannot become a gas unless?
It absorbs heat which does not raise its temperature
A gas cannot become a liquid unless?
It gives off heat which does not lower it’s temperature
How do refrigerants work?
They absorb heat by evaporating at a low temperature and pressure and release heat by condensing at a higher temperature and pressure
What temperature does water boil at at 5000 feet?
203°F (95°C)
How does heat travel?
From a warm object to a colder one (warm to cold)
What is sensible heat?
The heat required to produce a change in temperature but not a change in state
What is specific heat?
The number of BTU’s required to raise the temperature of 1 pound of a sunstance by 1°F
What is the specific heat capacity of ice and steam?
0.5 Btu/lb/°F
What is the specific heat capacity of water?
1 BTU/lb/°F
What is latent heat?
The amount of heat required to change the state of a substance without changing its temperature
How many BTU are required to change 1 pound of ice to a liquid?
144 BTU
How many BTU are required to change liquid water into steam?
970 BTU
How many BTU are in 1 ton of refrigeration?
12000 BTU/hr
What colours coordinate with the high side and low side of a manifold pressure gauge set?
Red for high side
Blue for low side
When exposed to an open flame, refrigerants that contain fluorocarbons break down to produce what?
Dangerous poisonous vapours?
How full should a refrigerant container be?
Never fill a refrigerant container over 80% full of liquid refrigerant
How should you pressure test an air conditioning system?
Never used compressed air instead use an inert gas such as nitrogen
What is the latent heat value of ice?
144 BTU/lb
What is the specific heat capacity of ice?
0.5 BTU/lb/°F
What is the specific heat capacity of water?
1 BTU/lb/°F
What effect does pressure have on the boiling point of a substance?
Pressure increases boiling point increases
