Fundamentals Of Heat Transfer

Question 0

Conduction and convection are tied to hat kind of motion?

Answer 0

Molecular

Question 1

What are the three fundamental modes of heat transfer?

Answer 1

Conduction, convection, and radiation

Question 2

Radiation heat transfer is tied to what?

Answer 2

Electromagnetic waves

Question 3

True/false: radiation heat transfer requires a medium such as air or water through which to travel.

Answer 3

False.

Question 4

The movement of heat through a substance or between two substances in contact with each other is called what?

Answer 4

Conduction

Question 5

Which is the most efficient of the 3 types of heat transfers?

Answer 5

Conduction

Question 6

The rate of conduction heat transfer through a material is (blank) to the temperature difference between each surface and (blank) to the thickness of the material.

Answer 6

Proportional. Inversely proportional.

Question 7

Materials that resist heat flow are called what?

Answer 7

Thermal insulators

Question 8

Convection is heat transfer by the (blank)of heated or cooled (blank)

Answer 8

Motion. Mass

Question 9

True/false: radiative energy travels near the speed of light when unimpeded.

Answer 9

True

Question 10

Radiant heat transfer (does, does not) require a molecular medium for heat transfer to occur.

Answer 10

Does not

Question 11

Radiative energy is classified by length of what?

Answer 11

Wavelength

Question 12

What are the 3 most important waves associated with thermal radiation?

Answer 12

Ultraviolet, visible light, and infrared

Question 13

In radiant heat transfer, higher temperature bodies emit (smaller, larger), (more powerful, less powerful) wavelengths

Answer 13

Smaller. More powerful

Question 14

With translucent materials, the capability of the surface of the receiving body to transmit, absorb, and reflect radiative energy varies with the size of (blank) striking the surface.

Answer 14

Wavelength

Question 15

The radiative energy emitted by the surface of a body is called what?

Answer 15

Emissive power or emmittence.

Question 16

A (blank) is a hypothetical globe-shaped body that absorbs all of the radiative energy striking it, and emits all of this radiative energy.

Answer 16

Black body

Question 17

Heat passing through materials in a building envelope is called what?

Answer 17

Transmission heat loss

Question 18

Thermal conductivity describes a (blank) material’s ability to (blank)

Answer 18

Homogeneous. Transfer heat

Question 19

A heterogeneous or composite materials ability to transfer heat is called what?

Answer 19

Thermal conductance.

Question 20

A measure of a material’s ability to resist heat transfer is called what?

Answer 20

Thermal resistance.

Question 21

The denser a material, the (more/less) resistance it has to the flow of heat and the (higher/lower) it’s resistance value (R). The lighter, less dense the material, the (higher/lower) it’s R value and insulating value.

Answer 21

Lower. Lower. Higher.

Question 22

What is total thermal resistance?

Answer 22

The insulating ability of a construction assembly of materials, including air films.

Question 23

The Total Thermal Resistance of construction assembly of materials is determined by adding the (blank) of each component.

Answer 23

Thermal resistances

Question 24

the ability of a construction assembly to transfer heat, from exterior to exterior, including air films is called what?

Answer 24

The Overall Coefficient of Heat Transmission

Question 25

A (blank) in a building envelope assembly or component is a penetration of the insulation layer by a highly conductive or non insulating material.

Answer 25

Thermal bridge.

Question 26

Name three methods to express thermal resistance (R) properties of a construction assembly.

Answer 26

Center of cavity R value
Clear-wall R value
Whole wall R value

Question 27

The center of cavity R value is an R value estimation at a point in the assemblies cross section containing the most (blank)

Answer 27

Insulation

Question 28

The clear wall R value is an R value estimation for the exterior wall area containing only (blank) and necessary (blank) for a clear section with no fenestration, corners, or connections between other envelope elements.

Answer 28

Insulation

framing materials

Question 29

The whole wall R value is an R value estimation for the (blank) including including the thermal performance of the clear wall area and envelope interference detailsipoh.

Answer 29

Whole opaque wall

Question 30

A temperature gradient exists when there is a change in (blank) over some (blank) across a material.

Answer 30

Temperature

Distance

Question 31

What is the difference between natural convection and forced convection?

Answer 31

Natural convection occurs naturally and forced convection occurs by mechanical means

Question 32

What is heating load?

Answer 32

It is the heat that the HVAC equipment must generate me introduce into the building to Into comfortable conditions.