AZ ROC C-49 Industrial Refrigeration Practice Questions - Arizona ROC C-49 Industrial Refrigeration (Commercial) Examination Exam - AZ ROC C-49 Industrial Refrigeration Practice Questions - Arizona ROC C-49 Industrial Refrigeration (Commercial) Examination Exam

Question 1

Under ASHRAE Standard 34, what is the safety classification for anhydrous ammonia (R-717)?

A1 (lower toxicity, no flame propagation) B2L (higher toxicity, lower flammability with burning velocity ≤ 10 cm/s) A2L (lower toxicity, lower flammability) B1 (higher toxicity, no flame propagation)

Correct Answer:

B2L (higher toxicity, lower flammability with burning velocity ≤ 10 cm/s)

Question 2

What is the approximate critical temperature and critical pressure above which carbon dioxide (R-744) operates in a transcritical cycle?

87.8°F (31.1°C) and 1,055 psig (7.38 MPa) 120.4°F (49.1°C) and 650 psig (4.48 MPa) 45.2°F (7.3°C) and 1,450 psig (10.0 MPa) 104.0°F (40.0°C) and 850 psig (5.86 MPa)

Correct Answer:

87.8°F (31.1°C) and 1,055 psig (7.38 MPa)

Question 3

In an industrial rotary screw compressor package, how does the hydraulic slide valve modulate refrigeration capacity?

By throttling the main suction stop valve to restrict gas entering the rotors. By adjusting the motor frequency via an external resistance grid. By moving axially along the rotor bore to bypass uncompressed suction gas back to the suction port before compression begins. By opening a high-pressure bypass valve that recirculates hot discharge gas into the oil separator.

Correct Answer:

By moving axially along the rotor bore to bypass uncompressed suction gas back to the suction port before compression begins.

Question 4

What are the two primary thermal functions of a flash-type intercooler in a two-stage ammonia (R-717) refrigeration system?

To condense high-stage discharge gas and warm low-stage liquid feed. To subcool high-pressure suction gas and heat low-stage compressor oil. To generate superheated vapor for hot gas defrost and drain high-side receiver oil. To desuperheat low-stage (booster) compressor discharge gas and subcool liquid refrigerant feeding low-stage evaporators.

Correct Answer:

To desuperheat low-stage (booster) compressor discharge gas and subcool liquid refrigerant feeding low-stage evaporators.

Question 5

What is the primary thermodynamic advantage of utilizing a liquid overfeed (recirculator pump) system in a commercial cold storage facility compared to a direct expansion (DX) system?

Evaporator internal tube surfaces remain completely wetted with liquid, maximizing the overall heat transfer coefficient without requiring superheat at the coil outlet. It eliminates the requirement for low-side suction accumulators and surge drums. It allows the system to operate with zero compressor discharge superheat. It reduces total system refrigerant charge by 80% compared to DX systems.

Correct Answer:

Evaporator internal tube surfaces remain completely wetted with liquid, maximizing the overall heat transfer coefficient without requiring superheat at the coil outlet.

Question 1

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Prepare with the AZ ROC C-49 Industrial Refrigeration Practice Questions - Arizona ROC C-49 Industrial Refrigeration (Commercial) Examination Exam practice quiz. This question bank includes 100 questions covering refrigeration, ammonia, pressure, industrial, and liquid. Use it to review important concepts, identify knowledge gaps, and build confidence for the related exam, course, or assessment.

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AZ ROC C-49 Industrial Refrigeration Practice Questions - Arizona ROC C-49 Industrial Refrigeration (Commercial) Examination Exam

This practice set contains 100 questions from the matching question bank and focuses on refrigeration, ammonia, pressure, industrial, and liquid. Work through each question carefully, review the provided solutions, and revisit topics that need more study before your next attempt.

This is an independent study resource intended for practice and review; it is not an official examination or an endorsement by any organization named in the title.

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AZ ROC C-49 Industrial Refrigeration Practice Questions - Arizona ROC C-49 Industrial Refrigeration (Commercial) Examination Exam

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