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Questions and Answers
What are the broad areas that commercial refrigeration equipment is grouped in based on the evaporator coil temperature?
What are the broad areas that commercial refrigeration equipment is grouped in based on the evaporator coil temperature?
What is the normal storage temperature for food items like milk, cheese, fresh fruits and vegetables?
What is the normal storage temperature for food items like milk, cheese, fresh fruits and vegetables?
from 32°F to 40°F
A system that maintains temperatures of -250°F and below is a(n):
A system that maintains temperatures of -250°F and below is a(n):
A refrigerated case that maintains a temperature of 28°F would be classified as:
A refrigerated case that maintains a temperature of 28°F would be classified as:
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Why would a 35°F medium-temperature case need to defrost?
Why would a 35°F medium-temperature case need to defrost?
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What is the advantage of using multiple compressors on a supermarket rack system?
What is the advantage of using multiple compressors on a supermarket rack system?
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When multiple compressors are installed in parallel on the same refrigeration system, provisions must be made to ensure that:
When multiple compressors are installed in parallel on the same refrigeration system, provisions must be made to ensure that:
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What are the essential elements of a single-component system refrigeration system, in order?
What are the essential elements of a single-component system refrigeration system, in order?
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What refrigeration component makes it possible to use a single compressor to control multiple cases at different temperatures?
What refrigeration component makes it possible to use a single compressor to control multiple cases at different temperatures?
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What are three common methods of controlling evaporator temperature?
What are three common methods of controlling evaporator temperature?
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Why is a check valve installed in the suction line of the lowest temperature coil in a multiple evaporator system?
Why is a check valve installed in the suction line of the lowest temperature coil in a multiple evaporator system?
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What is the approximate ventilation requirement for low-temperature, air-cooled condensing units located indoors?
What is the approximate ventilation requirement for low-temperature, air-cooled condensing units located indoors?
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The defrost cycle is normally terminated:
The defrost cycle is normally terminated:
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What is commonly used to control defrost operations?
What is commonly used to control defrost operations?
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What is the purpose of the door switch on a walk-in freezer?
What is the purpose of the door switch on a walk-in freezer?
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Why should the evaporator not be installed above the door in a walk-in cooler or freezer?
Why should the evaporator not be installed above the door in a walk-in cooler or freezer?
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What is the first step in selecting commercial refrigeration equipment for a new installation?
What is the first step in selecting commercial refrigeration equipment for a new installation?
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What must be considered when performing a heat load calculation for a walk-in cooler or freezer?
What must be considered when performing a heat load calculation for a walk-in cooler or freezer?
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Study Notes
Commercial Refrigeration
- Commercial refrigeration equipment is categorized based on evaporator coil temperature into high, medium, low, and cryogenic systems.
- Normal storage temperature for perishable food items like milk, cheese, fresh fruits, and vegetables is maintained between 32°F to 40°F.
Temperature Classification
- Refrigerated cases maintaining a temperature of 28°F are classified as medium temperature systems.
- Cryogenic systems are designed to maintain temperatures of -250°F and below.
Defrosting and Temperature Control
- A 35°F medium-temperature case requires defrosting because its coil temperature operates below freezing.
- The defrost cycle is typically controlled by temperature, pressure, or time, often using a defrost timer.
Compressor Systems
- Utilizing multiple compressors in a supermarket rack system allows for better matching of system capacity to varying refrigeration loads.
- It is essential to maintain correct oil levels in all compressors when multiple compressors operate in parallel on the same system.
Refrigeration Components and Functions
- A single-component refrigeration system consists of an evaporator, compressor, condenser, and metering device in that specific order.
- An evaporator pressure regulator enables a single compressor to effectively control multiple cases at different temperatures.
Temperature Regulation Methods
- Three common methods for controlling evaporator temperature include conventional thermostats, suction pressure cut-out controls, and evaporator pressure regulators.
Systems Management
- Check valves are installed in the suction line of the lowest temperature coil in multiple evaporator systems to prevent refrigerant migration from higher to lower temperature coils.
- Low-temperature, air-cooled condensing units located indoors typically require approximately 200 CFM (Cubic Feet per Minute) of ventilation per 1,000 BTU.
Walk-in Freezer and Cooler Considerations
- The door switch on a walk-in freezer prevents warm air from entering by shutting off fans when the door is open.
- Evaporators should not be installed above doors in walk-in coolers or freezers to avoid drawing in warm, humid air that causes rapid frosting.
Installation Planning
- The first step in selecting commercial refrigeration equipment for a new installation involves performing a heat load calculation to assess the required BTU capacity of the system.
- Factors for consideration during a heat load calculation for a walk-in cooler or freezer include heat transmission, air infiltration, and product load.
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Description
This quiz covers the classification and operational details of commercial refrigeration systems. It explores temperature categories, defrosting mechanisms, and the function of compressor systems. Test your understanding of these critical components in food storage and preservation.
