Print this page Refrigeration Systems
A. Bhatia, B.E.
Course Outline
Most people think the refrigeration system’s job is simply to remove heat from an object. Actually there is no such thing “remove” the heat since heat is a form of energy than can’t be destroyed. We can only transfer heat from one place to another. Even though it is easier to think of refrigeration as the process of making things cold, it actually is the process of transferring heat from one place to another. It could also be said that refrigeration is the transfer of heat from one place where it is not wanted (walk in cooler), to another less objectionable place (outdoors).
This is just a very quick introduction to mechanical refrigeration system. This 4 -hour course provides more detailed information on the heat and refrigeration principles, refrigeration system components, type of refrigerants, methods of installation, maintaining, servicing and repairing the refrigeration systems and is entirely based on US Navy course - Utilitiesman Basic Volume 2: NAVEDTRA 14279 and covers chapter 6 titled “Refrigeration”.
This course includes a multiple-choice quiz at the end, which is designed to enhance the understanding of the course materials.
Learning Objective
At the conclusion of this course, the reader will:
- Understand the concepts of heat theory and the basic principles of refrigeration;
- Recognize various components of refrigeration systems and their application;
- Discuss and compare the basic types of commercial and domestic refrigeration equipment;
- Understand and classify common refrigerants according to their application;
- Understand the requirements for Ozone protection and the Clean Air Act;
- Understand the safety requirements for handling and storing of refrigerant and the procedures to determine leaks in refrigeration system;
- Understand the procedures for recovery, recycling and reclaiming refrigerant;
- Understand the basic requirements for the installation of refrigeration equipment;
- Understand different types of maintenance equipment and methods for basic maintenance, service and repair of refrigeration systems and components;
- Understand the importance and use of maintaining the inspecting logs for refrigeration equipment;
- Understand the repair procedures for common problems in open type refrigeration compressors; and
- Understand the basic maintenance of motors and methods of electrical troubleshooting of motors.
Intended
Audience
This course is aimed at mechanical and HVAC engineers, facility managers, H &S professionals, environmentalists, O & M personal, safety engineers, industrial hygienists, and engineers responsible for the design, purchase or upkeep of heating, ventilation and air conditioning systems.
Benefit to Attendees
Attendee of this course will get the technical oversight of the refrigeration process, equipments and refrigerants. The course will be extremely helpful to engineers who desire to build on their design experience by learning more about the procedures to install, operate, troubleshoot and maintain the refrigeration systems.
Course
Introduction
The job of the refrigeration cycle is to remove unwanted heat from one place and discharge it into another. To accomplish this, the refrigerant is pumped through a closed refrigeration system. If the system was not closed, it would be using up the refrigerant by dissipating it into the surrounding media; because it is closed, the same refrigerant is used over and over again, as it passes through the cycle removing some heat and discharging it. The closed cycle serves other purposes as well; it keeps the refrigerant from becoming contaminated and controls its flow, for it is a liquid in some parts of the cycle and a gas or vapor in other phases. A mechanical refrigeration system consists of 4 essential components:
1. An Evaporator to absorb heat into the refrigerant system
2. A Condenser to reject the heat from the refrigerant system
3. A Compressor to establish the pressures required to force the heat to travel "uphill."
4. A Liquid Metering Device to regulate the flow of refrigerant and to establish two pressure zones.
The normal strategy is to get the heat to the refrigerant in an evaporator and then transfer the refrigerant to a condenser where the heat can be removed from it. It is this cycle that moves and remove heat from one place to another.
This is just a very quick introduction to mechanical refrigeration system. This course provides more detailed information on the heat and refrigeration principles, refrigeration system components, types of refrigerant, methods of installation, maintaining, servicing and repairing the refrigeration systems.
Course Content
This course is entirely based on US Navy course - Utilitiesman Basic Volume 2: NAVEDTRA 14279 and covers chapter 6 titled “Refrigeration”.
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Course Summary
In a refrigeration system, heat travels from the warmer substance to the evaporator cooled by the working fluid or refrigerant in a closed loop. A mechanical refrigeration system consists of 4 basic major components - evaporator, compressor, condenser, and metering device. Tubing or "lines" make the system complete so that the refrigerant will not leak out into the atmosphere. The suction line connects the evaporator to the compressor, the hot gas or discharge line connects the compressor to the condenser, and the liquid line is the connecting tubing between the condenser and the metering device (thermal expansion valve). Some systems will have a receiver immediately after the condenser and before the metering device, where the refrigerant is stored until it is needed for heat removal in the evaporator.
The mechanical refrigeration system is essentially the same whether the system is a domestic refrigerator, a low-temperature freezer, comfort air conditioning system, industrial chiller, or commercial cooling equipment. Refrigerants will be different and size of the equipment will vary greatly, but the principle of operation and the refrigeration cycle remains the same. Thus, once you understand the simple actions that are taking place within the refrigeration mechanical cycle you should have a good understanding how a refrigeration system works.
Quiz
Once you finish studying the above course content, you need to take a quiz to obtain the PDH credits.
DISCLAIMER: The materials contained in the online course are not intended as a representation or warranty on the part of PDH Center or any other person/organization named herein. The materials are for general information only. They are not a substitute for competent professional advice. Application of this information to a specific project should be reviewed by a registered architect and/or professional engineer/surveyor. Anyone making use of the information set forth herein does so at their own risk and assumes any and all resulting liability arising therefrom.
