NATE EXAM: AIR CONDITIONING
AND HEAT PUMPS
Which70of70the70following70factors70affects70a70customer's70level70of70comfort?
a.70Air70movement
b.70Humidity
c.70Temperature
d.70All70of70the70above70-70answer--
d70(All70of70the70above:70air70movement,70humidity,70temperature)
A70cooling70load70calculation70estimates70the70sensible70heat70gain70of70a70structure.70T
he70maximum70sensible70capacity70of70a70cooling-
only70system70should70be70within70____%70of70this70calculated70value.
a.70±10%
b.70+10%
c.70+15%
d.70+30%70-70answer--c70(+15%)
The70maximum70sensible70cooling70capacity70of70a70heat70pump70should70be70within70_
___
%70of70the70calculated70sensible70heat70gain70of70a70structure70with70a70large70heating70l
oad.
a.70±10%
b.70+15%
c.70-25%
d.70+25%70-70answer--d70(+25%)
The70combined70output70of70a70heat70pump70and70its70auxiliary70heat70should70not70exc
eed70the70calculated70heat70loss70of70a70home70by70more70than70____%.
a.7010%
b.7015%
c.7020%
d.7025%70-70answer--b70(15%)
,What70amount70of70auxiliary70electric70heat70is70needed70when70the70output70of70a70heat
70pump70on70a70design70day70equals7018,80070Btuh70and70the70heat70loss70of70a70home7
0is7029,70070Btuh?
a.702.170kWh
b.703.270kWh
c.705.070kWh
d.7010.970kWh
Note:703,41370Btu/kW70-70answer--b70(3.270kWh)
The70three70processes70that70transfer70heat70energy70are70conduction,70convection,70an
d70____.
a.70concentration
b.70radiation
c.70refraction
d.70static70pressure70-70answer--b70(radiation)
Heat70transfer70that70occurs70when70substances70of70different70temperatures70are70in70c
ontact70with70each70other70is70called70____.
a.70concentration
b.70conduction
c.70convection
d.70radiation70-70answer--b70(conduction)
What70effect70does70raising70the70pressure70in70a70sealed70system70have70on70refrigera
nt?
a.70It70becomes70more70difficult70to70subcool70the70liquid70refrigerant
b.70It70becomes70more70difficult70to70superheat70the70refrigerant70vapor
c.70The70refrigerant's70boiling70point70decreases
d.70The70refrigerant's70boiling70point70increases70-70answer--
d70(The70refrigerant's70boiling70point70increases)
What70is70the70primary70danger70to70people70near70an70accidental70refrigerant70release7
0or70spill?
a.70Blurred70vision70caused70by70the70refrigerant70vapor70coming70in70contact70with70the
70eyes
b.70Changes70in70weather70patterns70caused70by70global70warming
c.70Damage70to70the70food70chain70caused70by70decreased70ozone70levels70in70the70stra
tosphere
, d.70Suffocation70caused70by70the70heavier70refrigerant70displacing70oxygen70in70the70air7
0-70answer--
d70(Suffocation70caused70by70the70heavier70refrigerant70displacing70oxygen70in70the70air)
The70maximum70temperature70at70which70refrigerant70may70be70stored70is70____°F70wh
en70the70container70is70no70more70than70____%70full70of70liquid70by70volume.
a.70120°F,7060%
b.70125°F,7060%
c.70125°F,7080%
d.70135°F,7080%70-70answer--c70(125°F,7080%)
Boiling70of70the70refrigerant70occurs70in70which70system70component?
a.70Compressor
b.70Condenser
c.70Evaporator
d.70Metering70device70-70answer--c70(Evaporator)
Why70is70superheat70necessary70in70a70system70that70utilizes70hermetic70compressors?
a.70It70ensures70that70dry70vapor70reaches70the70compressor70so70that70mechanical70da
mage70does70not70occur
b.70It70increases70system70capacity
c.70It70prevents70liquid70refrigerant70from70gassing70the70metering70device
d.70Superheat70is70necessary70only70when70open70compressors70are70being70used70-
70answer--
a70(It70ensures70that70dry70vapor70reaches70the70compressor70so70that70mechanical70da
mage70does70not70occur)
When70the70heat70load70on70an70evaporator70increases,70what70is70the70effect70on70the70
system?
a.70Suction70pressure70decreases70and70discharge70pressure70increases
b.70Suction70pressure70increases70and70discharge70pressure70decreases
c.70Suction70pressure70and70discharge70pressure70both70decrease
d.70Suction70pressure70and70discharge70pressure70both70increase70-70answer--
d70(Suction70pressure70and70discharge70pressure70both70increase)
What70type70of70energy70is70transferred70when70work70is70done70in70the70condenser?
a.70Latent70heat70energy
b.70Sensible70heat70energy
c.70Both70latent70and70sensible70heat70energy
d.70Neither70latent70nor70sensible70heat70energy70-70answer--
c70(Both70latent70and70sensible70heat70energy)
AND HEAT PUMPS
Which70of70the70following70factors70affects70a70customer's70level70of70comfort?
a.70Air70movement
b.70Humidity
c.70Temperature
d.70All70of70the70above70-70answer--
d70(All70of70the70above:70air70movement,70humidity,70temperature)
A70cooling70load70calculation70estimates70the70sensible70heat70gain70of70a70structure.70T
he70maximum70sensible70capacity70of70a70cooling-
only70system70should70be70within70____%70of70this70calculated70value.
a.70±10%
b.70+10%
c.70+15%
d.70+30%70-70answer--c70(+15%)
The70maximum70sensible70cooling70capacity70of70a70heat70pump70should70be70within70_
___
%70of70the70calculated70sensible70heat70gain70of70a70structure70with70a70large70heating70l
oad.
a.70±10%
b.70+15%
c.70-25%
d.70+25%70-70answer--d70(+25%)
The70combined70output70of70a70heat70pump70and70its70auxiliary70heat70should70not70exc
eed70the70calculated70heat70loss70of70a70home70by70more70than70____%.
a.7010%
b.7015%
c.7020%
d.7025%70-70answer--b70(15%)
,What70amount70of70auxiliary70electric70heat70is70needed70when70the70output70of70a70heat
70pump70on70a70design70day70equals7018,80070Btuh70and70the70heat70loss70of70a70home7
0is7029,70070Btuh?
a.702.170kWh
b.703.270kWh
c.705.070kWh
d.7010.970kWh
Note:703,41370Btu/kW70-70answer--b70(3.270kWh)
The70three70processes70that70transfer70heat70energy70are70conduction,70convection,70an
d70____.
a.70concentration
b.70radiation
c.70refraction
d.70static70pressure70-70answer--b70(radiation)
Heat70transfer70that70occurs70when70substances70of70different70temperatures70are70in70c
ontact70with70each70other70is70called70____.
a.70concentration
b.70conduction
c.70convection
d.70radiation70-70answer--b70(conduction)
What70effect70does70raising70the70pressure70in70a70sealed70system70have70on70refrigera
nt?
a.70It70becomes70more70difficult70to70subcool70the70liquid70refrigerant
b.70It70becomes70more70difficult70to70superheat70the70refrigerant70vapor
c.70The70refrigerant's70boiling70point70decreases
d.70The70refrigerant's70boiling70point70increases70-70answer--
d70(The70refrigerant's70boiling70point70increases)
What70is70the70primary70danger70to70people70near70an70accidental70refrigerant70release7
0or70spill?
a.70Blurred70vision70caused70by70the70refrigerant70vapor70coming70in70contact70with70the
70eyes
b.70Changes70in70weather70patterns70caused70by70global70warming
c.70Damage70to70the70food70chain70caused70by70decreased70ozone70levels70in70the70stra
tosphere
, d.70Suffocation70caused70by70the70heavier70refrigerant70displacing70oxygen70in70the70air7
0-70answer--
d70(Suffocation70caused70by70the70heavier70refrigerant70displacing70oxygen70in70the70air)
The70maximum70temperature70at70which70refrigerant70may70be70stored70is70____°F70wh
en70the70container70is70no70more70than70____%70full70of70liquid70by70volume.
a.70120°F,7060%
b.70125°F,7060%
c.70125°F,7080%
d.70135°F,7080%70-70answer--c70(125°F,7080%)
Boiling70of70the70refrigerant70occurs70in70which70system70component?
a.70Compressor
b.70Condenser
c.70Evaporator
d.70Metering70device70-70answer--c70(Evaporator)
Why70is70superheat70necessary70in70a70system70that70utilizes70hermetic70compressors?
a.70It70ensures70that70dry70vapor70reaches70the70compressor70so70that70mechanical70da
mage70does70not70occur
b.70It70increases70system70capacity
c.70It70prevents70liquid70refrigerant70from70gassing70the70metering70device
d.70Superheat70is70necessary70only70when70open70compressors70are70being70used70-
70answer--
a70(It70ensures70that70dry70vapor70reaches70the70compressor70so70that70mechanical70da
mage70does70not70occur)
When70the70heat70load70on70an70evaporator70increases,70what70is70the70effect70on70the70
system?
a.70Suction70pressure70decreases70and70discharge70pressure70increases
b.70Suction70pressure70increases70and70discharge70pressure70decreases
c.70Suction70pressure70and70discharge70pressure70both70decrease
d.70Suction70pressure70and70discharge70pressure70both70increase70-70answer--
d70(Suction70pressure70and70discharge70pressure70both70increase)
What70type70of70energy70is70transferred70when70work70is70done70in70the70condenser?
a.70Latent70heat70energy
b.70Sensible70heat70energy
c.70Both70latent70and70sensible70heat70energy
d.70Neither70latent70nor70sensible70heat70energy70-70answer--
c70(Both70latent70and70sensible70heat70energy)
