Building Services Systems - Chapter 7 Vocabulary

Front 1

Filter

Back 1

A means to make an indirect (controlled) connection between inside and outside. (page 176)

Front 2

Connector

Back 2

A means to make a direct connection between inside and outside. (page 176)

Front 3

Barrier

Back 3

An element separating inside from outside (i.e. an opaque wall acts as a barrier to light). (page 176)

Front 4

Switch

Back 4

An element that can stop or connect at will (i.e. a door or window). (page 176)

Front 5

Transformer

Back 5

Converts an environmental force (such as sunlight) into a different and desirable energy form (such as electricity). (page 176)

Front 6

Conductors

Back 6

Materials that are dense, durable, and able to diffuse heat readily. (page 187)

Front 7

Insulators

Back 7

Materials that retard the flow of heat. Can be inorganic, organic, or metallic. (page 187)

Front 8

Selective Surfaces

Back 8

Sometimes used in solar collectors, are highly absorptive yet have very low emmitance. (page 187)

Front 9

Emmitance

Back 9

The ratio of radiation emitted by a given material to that emitted by a blackbody at the same temperature. (page 186)

Front 10

Resistance

Back 10

Designated as R, resistance indicates how effective any material is as an insulator. (page 186)

Front 11

Conductivity

Back 11

Designated as k. The number of British thermal units per hour (Btu/h) that flow through 1 square foot (ft²) of material that is 1 inch thick when the temperature difference across that material is 1°F. (page 183)

Front 12

Conductance

Back 12

Designated as C. The number of British thermal units per hour (Btu/h) that flow through 1 square foot (ft²) of a given thickness of material when the temperature difference across that material is 1°F. (page 185)

Front 13

Evaporation

Back 13

Heat loss that carries heat away from wet surfaces. (page 183)

Front 14

Radiation

Back 14

Heat flow via electromagnetic waves from hotter surfaces to detached, colder ones, across empty space. (page 183)

Front 15

Conduction

Back 15

Heat transfer directly from molecule to molecule, within or between materials.

Front 16

Convection

Back 16

Heat exchange between a fluid (typically air) and a solid, with motion of the fluid due to heating or cooling playing a critical role in the extent of heat transfer. (page 183)

Front 17

Energy

Back 17

Power usage over time. (page 183)

Front 18

Power

Back 18

Instantaneous flow of energy (at a given time). (page 183)

Front 19

Reflective

Back 19

A metallic insulating membrane. (page 187)

Front 20

U-factor

Back 20

The property that expresses the steady-state rate at which heat flows through architectural envelope assemblies. The U-factor is the reciprocal of the sum of resistances in an assembly.

Front 21

Insulating Layer

Back 21

A thin layer of air that "attaches" itself along a vertical surface when air motion is minimal. The resistance is equivalent to a 1/2" thickness of plywood, as long as it is not disturbed. (page 188)

Front 22

Radiant Barrier

Back 22

A reflective layer which is not attached to blanket or batt insulation. (page 187)

Front 23

Reflective

Back 23

A metallic or metalized organic membrane, which must face an air space to be effective. (page 187)

Front 24

Formed in Place

Back 24

Type of insulation, such as expanded pellets or liquid-fiber mixtures, that is poured, frothed, sprayed, or blown into place. (page 187)

Front 25

Insulating Cement

Back 25

A loose material mixed with a binder and troweled onto a surface. (page 187)

Front 26

Loose Fill

Back 26

A form-fitting insulating material. (page 187)

Front 27

Flexible/Semirigid

Back 27

An insulation in batts and blankets. (page 187)

Front 28

Rigid

Back 28

An insulation that comes in blocks, boards, and sheets, but can also be preformed. (page 187)

Front 29

Density

Back 29

The weight of a material per unit volume, expressed as lb/ft³. (page 196)

Front 30

Specific Heat

Back 30

The measure of the amount of heat required to raise the temperature of a given mass of material by 1°, expressed as Btu/lb °F. (page 196)

Front 31

Thermal Capacity

Back 31

An indicator of the ability of a fixed volume of material to store heat. Thermal capacity for a material is obtained by taking the product of density and specific heat. (page 196)

Front 32

Hard Coat

Back 32

A low-emittance (low-Ɛ) coating for glass, more durable and less expensive than a soft coat, but less thermally effective. (page 201)

Front 33

Soft Coat

Back 33

A low-emittance (low-Ɛ) coating for glass, better thermal performance, but more expensive than hard coat, and subject to degradation by oxidation. (page 201)

Front 34

Low Emittance

Back 34

A coating on glass that blocks a great deal of radiant transfer between panes. It is abbreviated low-Ɛ. (page 201)

Front 35

Superwindow

Back 35

Window that uses all of the currently available high-performance glazing options, such as multiple glazings, suspended films, coatings, inert gas, etc. (page 202)

Front 36

Smart Windows

Back 36

Future windows with on-demand variable light transmission. (page 205)