poop

How to you find ventilation rate? (Air changes)

Find space volume multiplied by required air changes

The part of the system where the refrigerant absorbs heat causing a cooling effect

Evaporator

The amount of heat required to change one pound of water 1 degree F

BTU

What is the most accurate way to define a refrigerant

Any fluid that has the ability to change states and absorb heat

The variation of air temperature in a building space that occurs when warm air rises and cooler air falls

stratification

What do heat pumps use to change the direction of refrigerant flow for heating and cooling capabilities

A reversing valve

What determines the temperature at which a refrigerant will vaporize

pressure

Boiling and condensing point at a given temperature

saturation

Heat transfer that results in a change of state

latent heat

Heat transfer that results in a change of temperature

Sensible heat

Latent heat value of water to ice

144 btus per pound

latent heat value of water to steam

970.3 btus per pound

Boiling or condensing point of a fluid at its corresponding pressure

saturation point

the heat required to raise one pound of a substance 1 degree f

specific heat

when a liquid turns into a vapor at low temps and pressures

evaporation

when a liquid turns into a vapor at high temps and pressures

vaporization

heat gained above saturation temp, can only be as a vapor

superheat

heat lost below saturation temp, can only be as a liquid

subcooling

the amount of energy in a substances molecules

heat

the measurement of energy in a substances molecules

temperature

output/input, has to be less then one

efficiency

comparing the density of a liquid to the density of water

specific weight

force of attraction between molecules of the same kind

cohesion

attraction between molecules of different kinds

adhesion

Molecular motion energy

kinetic energy

stored energy

potential energy

What kind of relationship do pressure and boiling point have

direct proportion

if pressure is increased and temperature is constant, what happens to volume

it decreases

How do you calculate absolute pressure

Gauge pressure + atmosphereic pressure, or atmosphere pressure - vacuum

What is considered a vacuum

Anything less than atmospheric pressure (14.7 psi)

When pressure is applied to a closed fluid, pressure will be transmitted equally in all directions (law of hydraulics)

Pascal’s principle

An object immersed in fluid will displace fluid equal to the weight of the object (buoyancy)

Archemedies principle

If volume is constant, pressure and temperature are proportional

Charles law

If temperature is constant, pressure and temperature are inverse proportional

Boyles law

If there are a mixture of gases in a vessel, the pressures add up

Daltons law

How many inches of mercury equal one psi

0.491

How many psi per foot of water head

0.433

how to calculate total force (VAPOR ONLY)

area x pressure or volume x density if its for a liquid then its the weight of the liquid

what is the equation for work

work = force x distance measured in foot pounds

What is the equation for horse power

work/33000xminutes or work/550xseconds

What is the equation for sensible heat transfer

Btus/hr = Sensible heat x weight x delta T

What is the equation for latent heat transfer

btus/hr = latent heat x weight

What is the sensible heat value of water

1

What is the sensible heat value of ice

0.5

how many btus are in a ton

12,000

What is the combined gas law equation

p1xv1/t1 = p2xv2/t2

What are absolute pressure and temperature

14.7 psi and 460 degrees

What are standard pressure and temperature

14.7 psi and 32 degrees

What is the equation for total expanded volume

COE x Volume x Delta T

What is the equation for total expanded length

COE x Length x Delta T

What is the equation for total heat (Air)

Btus/hr = 4.5 x CFM x Delta H

What is the equation for sensible heat (air)

btus/hr = 1.08 x CFM x Delta T

What is the max amount of grains 1 pound of air can hold

7000

what is the recommended amount of cfm per ton

400

What is high voltage

Anything above 600

what is line voltage

115-600 volts

What is low voltage

anything below 50

what are the 2 kinds of motors

open and totally enclosed

what are the 2 main parts of the motor

stator and rotor

what are the 2 different types of overloads

thermal and magnetic

What kind of overloads can you set

magnetic

What what is another name for thermal overloads

heaters