Reta Caro Study Guide JH Exam Questions
With Verified Solutions
Which is equal to 22 Psig?
36.7 Psia
What is the Latent Heat of Vaporization?(H2O)
970 Btu's
What product requires the most energy to lower 1 lb. by 1 degree?
water
What happens when pressure on a liquid is increased?
Boiling point goes up/Saturation temp. goes up
What happens when vapor is Superheated?
Temperature above saturated/it gains sensible heat 0.5x1 degree F
What causes heat to move from one object to another when touched?
temperature difference/ conduction
What Btu's are needed to convert 10 lbs. of water to 10 lbs. of steam?
10x970= 9,700 Btu's
What rate describes the load for 120 tons?(in Btu's/Hr.)
Btu/hr= 12,000 so 12,000x120=1,440,000
What is equivalent to 48,000 Btu/hr. in tons?
48,000 divided by 12,000 = 4 tons
What is 100 degrees Celsius in Farenheight?
212 degrees farenheight
figure* Single Stage- Saturation should never occur in?
compressor
figure* Single Stage- Where is heat absorbed from the product?
Evaporator
What is compressed in refrigerant vapors?
vapors
What best describes refrigerants boiling rapidly?
saturated/ It's evaporating
, What is the condensation in a pipe with R-22 at 20Psig & 10 degrees farenheight?
-5 degrees farenheight, 32.8Psig
What is indicated when evaporative condensation liquid drain is 90 degrees farenheight and 180Psig?
subcooled 5 degrees, or non-condensables
Where do non-condensable gasses accumulate?
They accumulate in the system's high side
What is the greatest threat to maintaining optimal operating pressures in a refrigeration system?
Air leaking into the system
What is most likely to result from an excessive discharge temp. at outlet of compressor due to non-
condensables in refrigeration system?
breakdown of oil, higher compression ratio, non-condensables accumulate breakdown of lubricants
and refrigerants
What is the temp. for R-22 at 182 Psig? (chart)
95 degrees
What refrigerant is lighter than air at the same temp.?
Ammonia
Ammonia vapor is flammable at what concentration?
16-25%
What best describes pipe fitting for ammonia?
Copper corrodes fast when moisture
Which of these may occur when Ammonia is exposed to hot metallic surfaces?
Decomposition may occur resulting in release of hydrogen gas.
Which statement best describes HCHF's?
R-22
Which best describes Ammonia at 80 degrees and 177.99Psig?
80 degrees= 138Psig= non-condensables in the system
What is the evaporating pressure for R-22 at 20 degrees?
43Psig
Which best describes a hermetic compressor's advantages?
With Verified Solutions
Which is equal to 22 Psig?
36.7 Psia
What is the Latent Heat of Vaporization?(H2O)
970 Btu's
What product requires the most energy to lower 1 lb. by 1 degree?
water
What happens when pressure on a liquid is increased?
Boiling point goes up/Saturation temp. goes up
What happens when vapor is Superheated?
Temperature above saturated/it gains sensible heat 0.5x1 degree F
What causes heat to move from one object to another when touched?
temperature difference/ conduction
What Btu's are needed to convert 10 lbs. of water to 10 lbs. of steam?
10x970= 9,700 Btu's
What rate describes the load for 120 tons?(in Btu's/Hr.)
Btu/hr= 12,000 so 12,000x120=1,440,000
What is equivalent to 48,000 Btu/hr. in tons?
48,000 divided by 12,000 = 4 tons
What is 100 degrees Celsius in Farenheight?
212 degrees farenheight
figure* Single Stage- Saturation should never occur in?
compressor
figure* Single Stage- Where is heat absorbed from the product?
Evaporator
What is compressed in refrigerant vapors?
vapors
What best describes refrigerants boiling rapidly?
saturated/ It's evaporating
, What is the condensation in a pipe with R-22 at 20Psig & 10 degrees farenheight?
-5 degrees farenheight, 32.8Psig
What is indicated when evaporative condensation liquid drain is 90 degrees farenheight and 180Psig?
subcooled 5 degrees, or non-condensables
Where do non-condensable gasses accumulate?
They accumulate in the system's high side
What is the greatest threat to maintaining optimal operating pressures in a refrigeration system?
Air leaking into the system
What is most likely to result from an excessive discharge temp. at outlet of compressor due to non-
condensables in refrigeration system?
breakdown of oil, higher compression ratio, non-condensables accumulate breakdown of lubricants
and refrigerants
What is the temp. for R-22 at 182 Psig? (chart)
95 degrees
What refrigerant is lighter than air at the same temp.?
Ammonia
Ammonia vapor is flammable at what concentration?
16-25%
What best describes pipe fitting for ammonia?
Copper corrodes fast when moisture
Which of these may occur when Ammonia is exposed to hot metallic surfaces?
Decomposition may occur resulting in release of hydrogen gas.
Which statement best describes HCHF's?
R-22
Which best describes Ammonia at 80 degrees and 177.99Psig?
80 degrees= 138Psig= non-condensables in the system
What is the evaporating pressure for R-22 at 20 degrees?
43Psig
Which best describes a hermetic compressor's advantages?
