Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
30 Cards in this Set
- Front
- Back
|
Latent Heat
|
Transferred heat that causes a change in state; as in ice melting
|
|
|
Sensible Heat
|
Transferred heat that causes a change in temperature
|
|
|
Heat always more from ______ to ______
|
Hot Cold
|
|
|
Specific heat is
|
The amount of heat that a specific material can store measured in Btus required to change material 1 degree F
|
|
|
heat transferrence between two objects not in contact and not shielded from each other
|
radiation
|
|
|
The rate of radiative exchange is based on
|
The surface temperature of the objects
the viewed angle emissivity (higher emissivity = higher rate of heat radiation) |
|
|
emissivity and absorption of a material are usually the same at a given wavelength
|
True
black objects absorb heat rapidly and cool rapidly |
|
|
Surfaces that have a high absorptivity in one wavelength (usually solar) and low emissivity in another (usually infared) are called
|
Selective Surfaces
|
|
|
transmissivity
|
the measure of how easily a material allows radiant energy to pass through it
|
|
|
the heat exchanges process that occurs only in a fluid medium such as air or liquid
|
Convection
|
|
|
heat transfer that is strictly directional
|
Convection - never transmits hear downward
|
|
|
The difference in pressure in a vertical space (positive or outward at the top and negative or inward at the bottom) is called
|
stack effect
|
|
|
Heat transfer process that occurs when objects are in direct contact
|
Conduction
|
|
|
The resistance value (R) is calculated by
|
x/k = R
x = thickness k = conductivity 6" concrete (k=9, x=6") 6/9 = .67 |
|
|
Insolation is a form of
|
radiation (Solar gain)
|
|
|
Mean Radiant Temperature relates to
A. air temperature B. surrounding surface temperatures C. body temperature D. all of the above |
B. Surrounding surface temperatures
|
|
|
Measures the temperature over a period of time against a reference temperature
|
degree day
|
|
|
A theoretical day that is "worse" (either colder or hotter) than 98 percent of the days experienced at a site
|
design day
|
|
|
The air change method and crack method are used to calculate _________?
|
infiltration
|
|
|
Cooling Load Temperature Differential (CLTD) is used to calculate
|
heat gain through walls
|
|
|
a graph that shows the air at different temperatures and different humidities
|
psychometric chart
|
|
|
The total amount of energy stored (sensible heat + latent heat)
|
Enthalpy
|
|
|
The percentage of saturation at the current temperature
|
relative humidity
|
|
|
What is a sling psychrometer?
|
A method of measuring wet bulb temperatures with a manual device
|
|
|
A mass wall that causes a convective loop into the room behind it when it is warmed
|
Trombe wall
|
|
|
I = V/R
|
Ohms Law
I = Current (amps) V = Voltage (volts) R = Resistance (ohms) |
|
|
Current that flows in only one direction with constant voltage
|
DC Current
|
|
|
P = V x I
|
Power (watts) in a DC circuit
|
|
|
the typical AC power frequency in the US
|
60 Hertz
|
|
|
1 ton = ? BTU/hr
|
12000 BTU/Hr
|
