Applied Science & Math Flashcards
Matter is commonly explained as a substance that occupies space and has
Mass
Solid mass exerts pressure
Downward only
Liquid mass exerts pressure
Down and outward
The “Law of Conservation of Energy” states that energy is neither created nor destroyed but
Can be converted from one form to another
Dalton’s Law of Partial Pressures shows that the total pressure of a confined mixture of gases is
The sum of all the gases
Heat flow is always in the direction of
Hot to cold
Latent heat is experienced
Water turns to steam
When ice melts
Convert 70 degrees Fahrenheit to Celsius
21
C = F – 32/1.8 C= 21
An increase of temperature on a confined gas creates
An increase in pressure
What is the pressure of R-22 Refrigerant if the temperature is 32 degrees f?
57.5 psi
An evaporator’s primary purpose is to
Absorb heat from the refrigerated product
Residential and light commercial HVAC systems typically use
Reciprocating compressors
Rotary compressors
Scroll compressors
The condenser receives hot refrigerant vapor from the compressor and
Cools the refrigerant causing a latent heat exchange
Removes heat from the refrigerant causing a sensible heat change
Residential and light commercial HVAC systems typically use
Capillary metering
Thermal expansion valve metering
Automatic expansion valve metering
The most common refrigerant used in existing modern residential or light commercial air conditioning systems is
R-22
Refrigerant 410 has special characteristics including higher operating pressure, a small temperature glide and is
A near azeotrope
Absorbing heat in the evaporator causes the refrigerant to
Boil
What is the volume of an office 20 feet wide, 30 feet long and 10 feet high?
600 cubic feet
20’ x 30’ x 10’ = 600 Cu. Ft.
The nominal evaporator CFM per 1 ton of air conditioning is _______ ?
400
. The deep vacuum is measured with a micron gauge, how many microns are in 1 inch?
25,400
If a motor operating 1725 RPM is turning a blower wheel at 500 RPM and
the blower pulley is 12”, what is the diameter of the motor pulley?
- 5
3. 5 = 1725 x 12/500
How many watts are required to operate a 1 hp motor for a period of 1 hour
746 watts
