Definitions - ballast 27

Question 1

The total solar radiation on a horizontal surface

Answer 1

Insolation

Question 2

heat that causes a change of state of a substance, such as the heat required to change water into steam.

Answer 2

latent heat

Question 3

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

Answer 3

sensible heat

Question 4

the number of Btus Goules) required to raise the temperature of a specific material by 1°F (lK). Specific heat is a measure of a material’s capacity to store heat as compared with the storage capacity of water.

Answer 4

specific heat

Question 5

the energy produced per unit of surface area per hour by a seated person at rest.

Answer 5

met

Question 6

is the transfer of heat through the movement of a fluid, either a gas or liquid.

Answer 6

convection

Question 7

nis the transfer of heat energy through electromag- netic waves from one surface to a colder surface

Answer 7

radiation

Question 8

is the transfer of heat through direct contact between two objects of different temperatures.

Answer 8

conduction

Question 9

attempts to combine the effects of air tempera- ture, humidity, and air movement.

Answer 9

Effective temperature ET

Question 10

is a measure of its ability to absorb and then radiate heat.

Answer 10

emissivity

Question 11

is a weighted average of the various surface temperatures in a room and the angle of exposure of the occupant to these surfaces, as well as of any sunlight present.

Answer 11

mean radiant temperature MRT

Question 12

is an average of the air temperature of a space and the mean radiant temperature (MRT) of the space. It can be measured with a globe thermometer, which is a thermometer inside a black globe.

Answer 12

operative temperature

Question 13

To quantify the effects of clothing the unit of the ___ was developed. One do is about equal to the typical American man’s business suit

Answer 13

clo

Question 14

preferred humidity levels

Answer 14

30-65%

Question 15

The study of the water vapor content of air is known as

Answer 15

psychrometry

Question 16

which is the amount of heat lost through 1 ft 2 of a 1 in thickness of the material when the temperature differ- ential is 1°F

Answer 16

conductivity k. Conductance,C, is the same property, but when the material is a thickness other than 1 in.

Question 17

is the number of hours needed for 1 Btu to pass through a material of a given thickness when the tem- perature differential is 1°F

Answer 17

R

R=1/C

Question 18

When a building assembly consists of more than one mate- rial, the value used to calculate heat loss is the

Answer 18

coefficient of heat transmission, U

U=1/sum(R)

Question 19

This value, calculated through complex formulas, takes into account the air temperature differences, effects of the sun, thermal mass storage effects of materials, colors of finishes exposed to the sun, and the daily temperature range.

Answer 19

design equivalent temperature difference (DETD)

Question 20

Heat gain through glazing can be a very significant factor. It is calculated by multiplying the area of the glazing by the

Answer 20

design cooling load factor (DCLF)