True/False
Indicate whether the
statement is true or false.
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1.
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The pressure/enthalpy chart for each refrigerant is different.
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2.
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If a line is moving from left to right on the p/e (often referred to as p/h)
chart, it is showing that the refrigerant is gaining enthalpy.
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3.
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Above the critical pressure point on the saturation curve the refrigerant is
liquid.
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4.
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If a point that is plotted on the refrigerant cycle falls on the constant
quality line that has a 60 beside it, this means that at that pont the refrigerant is 60 % vapor and
40 % liquid.
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Multiple Choice
Identify the
choice that best completes the statement or answers the question.
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5.
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If a point in the refrigeration cycle falls outside and to the left of the
saturation curves, ( page 65) the refrigerant at that point is:
a. | 10 % liquid, 90 % vapor | c. | 90 % liquid, 10 %
vapor | b. | superheated 100 % vapor | d. | subcooled 100 % liquid |
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6.
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The lines of constant temperature run:
a. | horizontally across the p/h chart | c. | run both horizontally and
vertically across the p/h chart | b. | run vertically across the p/h
chart | d. | none of the
above |
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7.
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Lines of constant enthalpy run:
a. | diagonally across the p/h chart | c. | horizontally across the p/h
chart | b. | vertically across the p/h chart | d. | none of the
above |
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8.
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If a line representing a portion of the refrigeration cycle moves horizontally
across the p/h chart from left to right:
a. | enthalpy is increasing | c. | temperature is remaining the same if the line is inside the
horseshoe shaped saturation area | b. | pressure is remaining the
same | d. | all of the
above |
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9.
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If a line representing a portion of the refrigeration cycle is moving downward
vertically across the p/h chart and begins its movement at a point just to the upper left and outside
the horseshoe shaped saturation area then moves into the saturation area (point A to point B, Figure
3.55, pg. 71), the refrigerant at point A is:
a. | high pressure, subcooled liquid | c. | high pressure 75 % liquid, 25 %
vapor | b. | low pressure, superheated vapor | d. | none of the
above |
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10.
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If a line representing a portion of the refrigeration cycle is moving downward
vertically across the p/h chart and begins its movement at a point just to the upper left and outside
the horseshoe shaped saturation area then moves into the saturation area (point A to point B, Figure
3.55, pg. 71), the refrigerant at point B is:
a. | low pressure, 70 % liquid, 30 % vapor | c. | low pressure, 30 % liquid, 70 %
vapor | b. | low pressure 100 % superheated vapor | d. | none of the
above |
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11.
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If a line representing a portion of the refrigeration cycle is moving downward
vertically across the p/h chart and begins its movement at a point just to the upper left and outside
the horseshoe shaped saturation area then moves into the saturation area (point A to point B, Figure
3.55, pg. 71), the refrigerant from point A to point B:
a. | has not changed in pressure, has increased in enthalpy and has remained at the same
temperature | c. | has increased in pressure, has decreased in enthalpy, has increased in
temperature | b. | has no change in enthalpy, has decreased in temperature, has increased in
pressure | d. | has decreased in
pressure, has remained at the same enthalpy, has decreased in
temperature |
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12.
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If a line representing a portion of the refrigeration cycle is moving downward
vertically across the p/h chart and begins its movement at a point just to the upper left and outside
the horseshoe shaped saturation area then moves into the saturation area (point A to point B, Figure
3.55, pg. 71), the refrigerant at point A is:
a. | entering the condenser | c. | leaving the compressor | b. | entering the
compressor | d. | entering the
metering device |
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Completion
Complete each
statement.
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13.
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On a p/e or p/h chart the starting or reference point for the heat content for
refrigerant is __________° F.
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14.
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The information found in the saturation curves on a p/h chart is the same
information found in the __________ chart with one exception.
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15.
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The left edge of the horseshoe shaped curve in the p/h chart is called the
__________ ____________ ___________ therefore the refrigerant at this point is 100 %
____________.
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16.
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The right edge of the horseshoe shaped curve in the p/h chart is called the
__________ ____________ ___________ therefore the refrigerant at this point is 100 %
____________.
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17.
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Any time a point on the refrigeration cycle falls within the saturation curves
the refrigerant is in the partial ________state, partial _________ state.
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18.
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The slanted near vertical lines within the saturation curves are called the
__________ ____________ lines and describe _______________________________________.
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Short Answer
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19.
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What is the name of the chart that gives a graphic picture of the refrigerant
cycle?
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20.
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What does enthalpy describe?
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21.
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What is the name given to the horseshoe shaped curve near the middle of the p/h
chart?
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22.
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What is the difference between the pressures found in the saturation curve and
the pressures shown on the p/t chart?
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23.
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Anytime a point is plotted for some part of the refrigeration cycle and it falls
on or within the saturation curve, what is the condition of the refrigerant at this time?
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24.
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What is the name given to the top of the horseshoe curve in the p/h
chart?
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25.
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In what portion of the p/h chart does the change of state in the refrigerant
occur?
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