Pretest quiz Flashcards

1
Q

Enthalpy describes:

a) moisture content in air
b) amount of refrigerant required in a system
c) amount of heat a substance contains
d) amount of heat a substance contains after boiling

A

c) the amount of heat a substance contains

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2
Q

When working with a pressure enthalpy diagram, what condition can be found to the right of the saturated vapour curve?

a) sub-cooked liquid
b) superheated vapour
c) saturated vapour
d) saturated liquid

A

superheated vapour

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3
Q

Define superheated refrigerant

A

temp of a vapour above its saturation temp

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4
Q

define sub-cooled refrigerant

A

temp of liquid when it’s cooled below it’s condensing temp

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5
Q

define saturated vapour refrigerant

A

when the temp is equal to its saturation temp

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6
Q

define saturated liquid refrigeration

A

when the temp is equal to its saturation temp

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7
Q

What does PH diagram mean

A

PE diagram

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8
Q

The vertical lines on a typical PE chart represent:

a) saturation curve
b) refrigerant in a liquid state
c) refrigerant in a vapour state
d) constant volume lines
e) constant quality lines
f) constant enthalpy lines
g) constant temp lines

A

constant enthalpy lines

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9
Q

The area between the saturated liquid curve and the saturated vapour curve PE chart represents

A

refrigerant in a liquid/vapour state

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10
Q

What is Thermal conductivity (K)

A

per inch thickness

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11
Q

What is Thermal conductance (C)

A

given thickness

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12
Q

What is Thermal resistance (R)

A

Material/Components resistance to heat transfer

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13
Q

One category of refrigeration is extra low temperature, what her names may be applied to this type of system?

A

Cryogenic, cascade and compound

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14
Q

Describe two applications of air conditioning systems?

A

comfort cooling and process cooling

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15
Q

Evaporator for refrigeration system will be constructed of a material with a ____ thermal resistivity and _____ thermal conductivity

A

low, high

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16
Q

Explain the difference between refrigerant vapour and refrigerant gas

A

vapour can be either saturated or superheated, gas is superheated

17
Q

Identify the methods of heat transfer and explain each in detail

A

Conduction: Molecule to molecule through physical contact

Convection: heat travels through fluid

Radiation: TD required

18
Q

What is Charles 1st law? and formula?

A

if volume of gas stays the same, then absolute pressure varies with absolute temp

P1xT2=P2xT1

19
Q

What is Charles 2nd law and formula?

A

If pressure of gas stays the same then volume of gas varies directly with absolute temp.

V1xT2=V2xT1

20
Q

What is Boyles law/formula?

A

If temp remains same then volume of gas varies inversely due to absolute pressure

P1xV1=P2xV2