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This is a sampling of the United States Army Combined Arms Support Command REFRIGERATION AND AIR CONDITIONING I Manual.

 

The excerpts are taken from the actual PDF Manual service members study.

 

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SUBCOURSE EDITION

OD1747 A

REFRIGERATION AND AIR CONDITIONING I

 

SUBCOURSE OVERVIEW

 

REFRIGERATION AND AIR CONDITIONING I

(Fundamentals)

Sub-course OD1747

Edition A

United States Army Combined Arms Support Command

Fort Lee, VA 23801-1809

10 Credit Hours

 

INTRODUCTION A

This sub-course is the first of four sub-courses devoted to basic instruction in refrigeration and air conditioning.

This sub-course explains the fundamentals of electricity and their application in the refrigeration process.

It discusses circuits, motors, and troubleshooting. This is followed by a discussion of fundamentals and the maintenance of the gasoline engine. The theory of refrigeration is also explained based on the characteristics of refrigerants.

Unless otherwise stated, whenever the masculine gender is used, both men and women are included.

 

INTRODUCTION

WITHIN THE LAST 20 years, refrigeration has become a vital part of American economy. Not only does nearly every household have its own private machine for the manufacture of ice and cold, but the vast industry of transporting, storing, and selling fresh foods would collapse overnight without the facilities to preserve fruits, meats, and vegetables.

Furthermore, many amazing therapies of medical science depend upon refrigeration.

All over the world the Army maintains bases equipped with the latest war materiel for keeping the peace or for defending our country. The men who man these bases must have suitable working conditions, proper food, and the best the hospital treatment possible.

In accomplishing these tasks, the Army makes use of every phase of refrigeration. Consequently, it must have men who will make a career of installing and maintaining the many refrigeration units it owns.

This course is offered to personnel who wish to improve their knowledge of the science of refrigeration.

This memorandum explains the fundamental reactions which make up the process of present-day refrigeration. It should help the man who is interested in increasing his knowledge of refrigeration.

Review exercises are at the end of each chapter.

 

ACKNOWLEDGMENT

Grateful acknowledgement is made to Allied Chemical Corporation; E. I. du Pont

Nemours and Company, Inc., and the American Society of Heating, Refrigeration, and

Air Conditioning Engineers for permission to use illustrations from their publications.

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CONTENTS

 

Introduction………………………………………………………………………………………………………………………i

Acknowledgement……………………………………………………………………………………………………………ii

Chapter 1 Principles Electricity………………………………………………………………………………………….1

2 Fundamentals of Gasoline Engines………………………………………………………………………………..41

3 Physics of Refrigeration……………………………………………………………………………………………….48

4 Refrigerants…………………………………………………………………………………………………………………58

Glossary………………………………………………………………………………………………………………………..63

Appendix……………………………………………………………………………………………………………………….66

Answer to Review Exercises……………………………………………………………………………………………77

 

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Principles of Electricity

 

We all use electrical equipment, such as lights, radio, television, electric stove and heaters, refrigerators, air conditioners and many more.

We use these items many times a day and accept them as a matter of course. As long as the electrical equipment operates properly, we accept it with little concern about what actually takes place.

Each of these devices operates because electric current flows through it.

2. To understand how electricity functions, you need to know the theory of electricity. The word “electric” is derived from the Greek word meaning “amber.” The ancient Greeks used the word describe the strange force of attraction and repulsion that was exhibited by amber after it had been rubbed with a cloth.

By knowing what electricity does, people have long ago developed theories which now are proving productive.

3. After centuries of experimentation by the world’s greatest scientists, laws by which electricity operates are becoming more widely known and better understood.

Also, the world has arrived at a generally accepted theory of the composition of matter. Therefore you must learn about “matter” and certain magnetic effects exhibited by matter.

 

1. Electrical Fundamentals

1-1. Matter means all substance – solids, liquids, and gases. Today, the accepted theory is that matter is composed of three long-lived particles and many more short-lived particles. We are concerned only with one of the three long-lived particles – the electrons.

1-2. Electron Flow

When there is general movement of electrons in one direction an electric current will flow.

The electrons, together with protons, (positively charged particles) and neutrons (neutral particles), make up atoms, of which all substances are composed.

The protons and neutrons are in the nucleus, (center of atom) and generally do not move about within a substance.

The remainder of the atom is composed of electrons, which are in constant motion about the nucleus.

1-3. Electrons move at a high rate of speed in orbit around the nucleus and carry a negative charge. The electrons apparently do not bunch up as the protons do in the nucleus. An atom may be compared to our planetary system, with the sun as the nucleus and the earth and other planets representing the electrons.

This is illustrated in figure 1, which shows the similarity between a hydrogen atom and our earth-sun system.

More complex atoms have a larger nucleus and additional electrons. The electrons are considered to be relatively loose and are usually considered to be that which make up an electric current or flow.

1-4. Electricity is often referred to as static electricity or dynamic electricity.

A generator is said to produce dynamic electricity, and from this comes the word “dynamo” as another name for a generator.

This is a machine which converts mechanical energy to electrical energy.

Generally speaking, we are able to control dynamic electricity so that it is a useful force which we can put to work.

A battery is also a source of dynamic electricity which we can control.

The chemical action in a battery produces electrical energy which has three useful applications in an automobile. It drives the electric motor which starts the engine. It supplies energy to the spark plugs as heat for ignition, and the car lamps also use electrical energy for light. The car’s generator recharges the battery and supplies the electric power when the engine is running.

Generators and batteries are the most widely used sources of dynamic electricity.

Now let’s discuss static electricity and its effects.

1-5. Effects of static electricity can be observed in dry weather when you run a comb through your hair. The crackling you hear is the result of small discharges of electricity, and in a dark room you can see the tiny flashes of light in a mirror.

Lightning in a summer storm is the violent discharge of tremendous static charges.

 

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You can obtain your PDF Survival Manual from most any of the sources I have noted on the RESOURCES page or any of the available references on the side columns.