TECH SYSTEMS THERMODYNAMICS
AND HEAT TRANSFER EXAM
QUESTIONS WITH VERIFIED ANSWERS
Heat Transfer phenomena associated to a radiant floor panel - ANSWER-Radiant Floor
heating is a process by which energy leaves the surface of an object and travels to the
surface of another (cooler) object in the form of radiation or electromagnetic waves.
Radiant: carries heat away from tubing and distributes it through joist space along the
floor. Convection: heating into liquid and conduction in the insulation layer: reduces heat
loss in the downward direction (back loss)
Basic Thermodynamic Principle of Refrigerator - ANSWER-Moves heat from inside the
cold icebox (heat source) to the warmer room-temperature air of the kitchen (heat sink).
Can be thought of as a heat engine, which is a heat pump in reverse. *See drawing
Principle of Air Conditioning - ANSWER-Works to cool a living space, moving heat from
the cooler interior (heat source) to the warmer outdoors (heat sink). *See Drawing
Pressure units - ANSWER-Pascals (Pa) - (N/(m^2))
Function of internal energy and its derivative - ANSWER-U(S,V, {Nj}) Derivations: *see
drawing
Definition of thermodynamic system and contour properties - ANSWER-A space
deliminated by a surface, having volume, containing matter, and owning energy. Its
surroundings can exchange heat, work, and mass. Intensive Properties: Chemical
Potential, Temperature, Pressure. Extensive Properties: Entropy, Internal Energy. *See
drawing
Heat transfer phenomena associated to ceiling radiant panels - ANSWER-Indoor air and
surfaces transfer heat to the ceiling panel through convection and radiation. The ceiling
panel surface transferred heat to external surface of chilled water tube through heat
conduction
Thermodynamics principle operation of a refrigerating machine - ANSWER-Gases get
hotter when you compress them into less volume because you have to work to push
their energetic molecules together. When you expand a gas, it is suddenly able to
occupy much more volume. The heat energy its molecules contain is now divided over a
much bigger volume of space, so the temperature of the gas falls (it gets cooler). The
other principle at work in a refrigerator is that when you have two things that are
different temperatures that touch or are near each other, the hotter surface cools and
the colder surface warms up. This is a law of physics called the Second Law of
Thermodynamics.
AND HEAT TRANSFER EXAM
QUESTIONS WITH VERIFIED ANSWERS
Heat Transfer phenomena associated to a radiant floor panel - ANSWER-Radiant Floor
heating is a process by which energy leaves the surface of an object and travels to the
surface of another (cooler) object in the form of radiation or electromagnetic waves.
Radiant: carries heat away from tubing and distributes it through joist space along the
floor. Convection: heating into liquid and conduction in the insulation layer: reduces heat
loss in the downward direction (back loss)
Basic Thermodynamic Principle of Refrigerator - ANSWER-Moves heat from inside the
cold icebox (heat source) to the warmer room-temperature air of the kitchen (heat sink).
Can be thought of as a heat engine, which is a heat pump in reverse. *See drawing
Principle of Air Conditioning - ANSWER-Works to cool a living space, moving heat from
the cooler interior (heat source) to the warmer outdoors (heat sink). *See Drawing
Pressure units - ANSWER-Pascals (Pa) - (N/(m^2))
Function of internal energy and its derivative - ANSWER-U(S,V, {Nj}) Derivations: *see
drawing
Definition of thermodynamic system and contour properties - ANSWER-A space
deliminated by a surface, having volume, containing matter, and owning energy. Its
surroundings can exchange heat, work, and mass. Intensive Properties: Chemical
Potential, Temperature, Pressure. Extensive Properties: Entropy, Internal Energy. *See
drawing
Heat transfer phenomena associated to ceiling radiant panels - ANSWER-Indoor air and
surfaces transfer heat to the ceiling panel through convection and radiation. The ceiling
panel surface transferred heat to external surface of chilled water tube through heat
conduction
Thermodynamics principle operation of a refrigerating machine - ANSWER-Gases get
hotter when you compress them into less volume because you have to work to push
their energetic molecules together. When you expand a gas, it is suddenly able to
occupy much more volume. The heat energy its molecules contain is now divided over a
much bigger volume of space, so the temperature of the gas falls (it gets cooler). The
other principle at work in a refrigerator is that when you have two things that are
different temperatures that touch or are near each other, the hotter surface cools and
the colder surface warms up. This is a law of physics called the Second Law of
Thermodynamics.
