Indoor Air Quality Flashcards
What is heat
Heat is a form of energy and causes the random vibration of molecules of a substance. Adding heat to a substance increases its molecular motion and potential energy.
What is cold
Cold is a term denoting the relative absence of heat. Absolute zero (-460 F -273 C)
What is temperature
Temperature is the measure of the intensity of heat of a substance or the measure of its molecular speed expressed in degrees
How do you change between C and F
C to F multiply 1.8 then add 32
F to C subtract 32 multiply by .556
Thermodynamics
The branch of science dealing with the mechanical action of heat.
The laws of thermodynamics
- Energy can neither be created or destroyed but can be converted from one type to another.
- Heat always travels from a warm object to a colder one.
What are the methods of heat transfer
Conduction
Radiation
convection
Latent heat of evaporation
What is conduction
This is the transfer of heat through a substance
What is convection heat.
Convection is the transfer of heat by natural motion of a fluid medium, either liquid or gas. The liquid or gas is first heated and this causes it to expand and become less dense thereby giving it more volume. The air becomes lighter and rises. Gravity furnace.
What is radiation
This is the transfer of heat by energy waves similar to light waves or radio waves. Ex. Sun’s heat is radiation transfer
What is sensible heat
The heat required to produce a change in temperature of a substance, but not a change in state. It can be measured with a thermometer or sense of touch.
Latent heat
The amount of heat required to change the state of a substance without changing its temperature. It is measured in btus.
What is latent heat of evaporation
The amount of heat required to change a liquid to a gas without changing its temperature
Specific heat
The number of btus required to raise the temperature of 1 pound of that substance 1 degree F Water has a specific heat of 1.0.
Define humidity
It is the quantity of water in a particular volume of air. Humid air is less dense than dry air.
What is the study of the properties of air?
Psychrometrics
What are the properties of air that can be controlled
Dry bulb temp Wet bulb temp Dew point temp Relative humidity Grains of moisture per pound of dry air Specific volume Enthalpy
Dry bulb temp
A measurement of the temperature of the air as recorded by a standard thermometer.
Wet bulb temp
The measurement of sensible heat minus the heat that is lost during the evaporation of the water of the wick.
What is dew point
The temperature that moisture will start to condense from the air