Commercial Refrigeration FINAL TEST 2024/2025 Questions and Answers (Graded A)
10 views 0 purchase
Course
Commercial Refrigeration
Institution
Commercial Refrigeration
Commercial Refrigeration FINAL TEST 2024/2025 Questions and Answers (Graded A)Commercial Refrigeration FINAL TEST 2024/2025 Questions and Answers (Graded A)Commercial Refrigeration FINAL TEST 2024/2025 Questions and Answers (Graded A)Commercial Refrigeration FINAL TEST 2024/2025 Questions and Answe...
Commercial Refrigeration FINAL
TEST 2024/2025 Questions and
Answers (Graded A)
How is the cooling effect in a mechanical refrigeration system produced? - ANSWER
- Evaporation of liquid refrigerant into vapor
What is the primary purpose of a compressor? - ANSWER - It circulates and
pressurizes the refrigerant vapor before the vapor Is condensed for re use
Name another function that must be performed by the compressor - ANSWER - Is
raise the pressure and temperature of the refrigerant vapor. This allows the
refrigerant to condense into a liquid as it circulates through the condenser
What characteristic defines an "open" type compressor? - ANSWER - Has a drive
shaft protruding from the compressor
What are the two main disadvantages of a hermetic compressor? - ANSWER - If
either the motor or compressor malfunctions, the entire unit must be replaced. The
motor is actually a part of the refrigerant circulation system. This means that a
burnout can contaminate the entire system
In a reciprocating compressor, the piston is connected to the crankshaft by a _____ -
ANSWER - Connecting rod
Name the three elements of performance that are the major factors in evaluating a
compressor - ANSWER - Efficiency, capacity, and economy of operation
If the suction gas superheat is too low, What could be the result? - ANSWER - Liquid
refrigerant might enter the compressor. This causes stress on the compressor
valves, wrist pins, rods, shaft, etc. It also causes excessive foaming of the oil in the
crankcase and other damaging effects. The compressor will not reach its rated
capacity
, What will happen if the suction gas temperature is too high? - ANSWER - Will cause
the compressor to run hot
What purpose do the fins attached to the condenser tubes serve? - ANSWER -
Increase the surface area for heat transfer
What is the purpose of subcooling? - ANSWER - To prevent the liquid from vaporizing
prematurely
If condensing pressure is higher than the corresponding condensing temperature,
what is normally the cause? - ANSWER - Non condensable gases
How is compressor efficiency often judged? - ANSWER - Btu per cubic foot (Btu/ft^3)
of displacement
When the same model of open type compressor is used with both air cooled and
water cooled condensing units, which is usually run at a slightly higher rpm? -
ANSWER - Water cooled
What is the equation for ratio of compression? - ANSWER - The absolute discharge
pressure (psig plus 14.7) divided by the absolute suction pressure (psig plus 14.7)
What type of compressor is found in large applications up to 10000 tons? - ANSWER
- Centrifugal compressors
Which compressor utilizes two helical rotors to compress the refrigerant gas? -
ANSWER - Screw compressor
What is the most outstanding advantage of the hermetically sealed compressor
over the open type? - ANSWER - Has no protruding crankshaft or shaft seal
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller NursingTutor1. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $12.99. You're not tied to anything after your purchase.
