Heat Gains and Losses Flashcards
External heat gains in a building are caused by:
A) Infiltration and heat gain from people and lighting
B) Exhausted air, radiation through windows, lighting
C) Infiltration, conduction, ventilation, and solar radiation
D) Hot water tanks, boilers, and appliances
E) Motors, boilers, and other mechanical equipment
C) Infiltration, conduction, ventilation, and solar radiation
Which of the following methods can be used to estimate the ventilation load on a building?
A) Conversion method B) The "U" factor method C) Crack method D) Conduction method E) Ventilation method
C) Crack method
Thermal conductance (C) may be defined as the:
A) Thermal heat flow by conduction only through a single uniform type of material (W/mK)
B) Thermal transmission through a unit area of a particular body where the difference between temperatures on either side of the body is unity (W/m2K)
C) Quantity of heat flow in unit time (Q or W)
D) Reciprocal of thermal conductance (mK/W)
E) Thermal heat flow through a unit of a non-uniform composite material when a unit average temperature difference is established between the surfaces (W/m2K)
E) Thermal heat flow through a unit of a non-uniform composite material when a unit average temperature difference is established between the surfaces (W/m2K)
Heat load from the people in a room is mostly affected by:
A) The number of people B) The activity of the people C) None of the above D) Smoking E) The size of the people
B) The activity of the people
One of the factors used to determine the ventilation rate in a building is the:
A) Solar load on the building
B) Type of electrical equipment used in the building
C) Cubic metre per hour (CFM) requirements per person
D) Activity in the building
E) Type of insulation used in the building
C) Cubic metre per hour (CFM) requirements per person
The resistance to heat flow through walls, floors, and windows is known as:
A) U-factor B) Ventilation C) Total thermal resistance D) Infiltration E) Reduced solar load
A) U-factor
Electric motors give off _____ while running.
A) Solar heat B) Sensible heat C) Latent and sensible heat D) No heat to the atmosphere E) Latent heat
B) Sensible heat
Heat lost from a building is:
A) Not affected by the density of the air
B) Affected by wind velocity
C) Is not affected by wind velocity
D) Dependent on the shape of the openings in a building
E) Independent from the outside air temperature
B) Affected by wind velocity
Rankine and Kelvin are absolute temperature scales whose starting point is absolute zero (the lowest temperature possible). They are related to Farenheit and Celsius temperature scales by:
A) C =Rankine - 460 , F = Kelvin - 273 B) C = Rankine - 273, F = Kelvin - 460 C) C = Kelvin - 460, F = Rankine + 273 D) C = Kelvin - 273, F = Rankine - 460 E) C = Kelvin - 460, F = Rankine - 273
D) C = Kelvin - 273, F = Rankine - 460
The amount of heat lost by a building due to conduction, convection, and infiltration is directly affected by:
A) Geographic location of the building B) The type of activity in the building C) The velocity of the wind D) The type of heating system used in the building E) Outside air temperature
C) The velocity of the wind
Rankine and Kelvin are absolute temperature scales whose starting point is absolute zero (the lowest temperature possible). Fahrenheit = Rankine – 460 . (zero R = 460 F, or, Freezing point of water = + 32 degrees Fahrenheit = + 492 Rankine) If Celsius = Kelvin -273, zero K = 273 C, then boiling point of water =
A) 560 K and 485 R B) 100 K and 212 R C) 373 K and 672 R D) 273 K and 460 R E) 173 K and 248 R
C) 373 K and 672 R
