Human Comfort & Mechanical Systems Fundamentals

Question 1

Define British Thermal Unit (Btu)

Answer 1

the amount of heat required to raise the temperatures of 1lbm of water by 1 degree Fahrenheit

Question 2

Coefficient of heat transmission

Answer 2

the overall rate of heat flow through any combination of materials, including airspaces and air layers on the interior and exterior of a building assembly. It is the reciprocal of the sum of all the resistances in the building assembly

Question 3

Conductance

Answer 3

the number of Btu per hour that pass through 1 sqft of homogeneous material of a given thickness when the temperature differential is 1 degree Fahrenheit

Question 4

Dew Point

Answer 4

The temperature at which water vapor in the air becomes saturated and begins to condense to drop of water.

Question 5

Dry-bulb temperature

Answer 5

the temperature of the air-water mixture is measured with a standard dry-bulb thermometer

Question 6

Enthalpy

Answer 6

the total heat in a substance, including latent heat and sensible heat

Question 7

Insolation

Answer 7

the total solar radiation on a horizontal surface

Question 8

Latent Heat

Answer 8

heat that causes a change of state of a substance, such as the heat required to change water into steam. The amount of heat required to change the state of a substance is much greater than the heat required to raise the temperature of the substance (sensible heat)

Question 9

Resistance

Answer 9

the number of hours needed for 1 Btu to pass through 1 sqft of material or assembly of a given thickness when the temperature differential is 1 degree Fahrenheit

Question 10

Sensible Heat

Answer 10

heat that causes a change in temperature of substance but not a change of state.