Manufacturing Engineering
Air Conditioning System Operations
Lesson Plan
Performance Objective
After completing this lesson, students will be able to explain air conditioning system operations to the
teacher’s satisfaction.
Specific Objectives
 Explain the theory of operation of an air conditioning system
 Research and discuss terms used in typical air conditioning systems
 Discuss an air conditioning system operational schematic diagram
Terms










1st Law of Thermodynamics- states that energy cannot be created or destroyed, but can only be
changed from one state to another.
2nd Law of Thermodynamics- states that heat always flows from a material with a high temperature to
a material with a low temperature.
British Thermal Unit (BTU)- a measurement of heat equal to the amount of heat required to raise one
pound of water one degree Fahrenheit.
Compressor- used to pressurize the refrigerant (changes it to a gas) and circulate the refrigerant
through the system.
Condenser- receives the hot pressurized gas from the evaporator and cools it (with the aid of fans) and
changes it back into a liquid through the condensation process. The liquid is returned to the
compressor to start the process all over again.
Evaporator- receives the cool pressurized gas from the compressor. The gas absorbs the heat from the
air and cools the air that is blown in to the house interior.
Heat transfer- the flow of heat from one body with higher temperature to another body that has a
lower temperature, until the two temperatures are equal. There must be a temperature difference
between the two materials for heat transfer to take place.
Refrigerant- the fluid used in heat transfer in a refrigeration system that absorbs heat by evaporation
at low temperature and pressure and gives up heat on condensing at higher temperatures and
pressures.
Thermal Expansion- an increase in the volume of a material as its temperature is increased.
Thermostat- senses the air temperature in the evaporator and controls the cooling process by turning
the compressor on and off as needed.
Time
When taught as written, this lesson should take approximately 180 minutes.
1
Copyright © Texas Education Agency, 2013. All rights reserved.
Preparation
TEKS Correlations
This lesson, as published, correlates to the following TEKS. Any changes/alterations to the activities may result
in the elimination of any or all of the TEKS listed.
Manufacturing Engineering 130.329 (c)
o (7) The student knows mechanical, fluid, electrical, and thermal systems. The student is
expected to:
(A) use pneumatics devices;
(B) use hydraulics devices;
(C) analyze the effects of heat energy and temperature on products; and
(D) develop an understanding of ventilation such as heating, air conditioning, and refrigeration.
Interdisciplinary Correlations
English Language Arts and Reading, English I 110.31 (b) (1) - Reading/Vocabulary Development. Students understand new vocabulary and use it
when reading and writing.

110.31 (b) (11) - Reading/Comprehension of Informational Text/Procedural Texts. Students
understand how to glean and use information in procedural texts and documents.
Algebra I 111.32 (b)
o (1) Foundations for functions. The student understands that a function represents a
dependence of one quantity on another and can be described in a variety of ways. The
student is expected to:
(E) interpret and make decisions, predictions, and critical judgments from functional
relationships.
World Geography Studies 113.43 (c)
o (19) Science, technology, and society. The student understands the impact of technology and
human modifications on the physical environment. The student is expected to:
(A) evaluate the significance of major technological innovations in the areas of transportation
and energy that have been used to modify the physical environment;
(B) analyze ways technological innovations such as air conditioning and desalinization have
allowed humans to adapt to places; and
(C) examine the environmental, economic, and social impacts of advances in technology on
agriculture and natural resources.
2
Copyright © Texas Education Agency, 2013. All rights reserved.

113.43 (c)
o (20) Science, technology, and society. The student understands how current technology
affects human interaction. The student is expected to:
(A) describe the impact of new information technologies such as the Internet, Global
Positioning System (GPS), or Geographic Information Systems (GIS); and
(B) examine the economic, environmental, and social effects of technology such as medical
advancements or changing trade patterns on societies at different levels of development.
Occupational Correlation (O*Net – www.onetonline.org/)
Job Title: Refrigeration Mechanics and Installers
O*Net Number: 49-9021.02
Similar Job Titles: Refrigeration Mechanic, Refrigeration Technician, Service Technician, Heating, Ventilation,
Air Conditioning / Refrigeration Technician (HVAC / R Technician), Heating, Ventilation, Air Conditioning
Technician (HVAC Technician), Heating, Ventilation, Air Conditioning Service Technician (HVAC Service
Technician)
Tasks
 Observe and test system operation, using gauges and instruments
 Adjust valves according to specifications and charge system with proper type of refrigerant by pumping
the specified gas or fluid into the system
 Test lines, components, and connections for leaks
 Dismantle malfunctioning systems and test components, using electrical, mechanical, and pneumatic
testing equipment
 Adjust or replace worn or defective mechanisms and parts, and reassemble repaired systems
 Braze or solder parts to repair defective joints and leaks
 Install wiring to connect components to an electric power source
Soft Skills
Critical Thinking/ Operation Monitoring/ Troubleshooting
Accommodations for Learning Differences
It is important that lessons accommodate the needs of every learner. These lessons may be modified to
accommodate your students with learning differences by referring to the files found on the Special
Populations page of this website.
Preparation
 Review and become familiar with the terminology, website links, and the slide presentation.
 Have materials, slide presentation, and websites ready to go prior to the start of the lesson.
3
Copyright © Texas Education Agency, 2013. All rights reserved.
References
 Refrigeration, http://en.wikipedia.org/wiki/Refrigeration, (December 30, 2012)
Instructional Aids
 Air Conditioning System Operations slide presentation and notes
 Air Conditioning System Operations Matching Terms and Definitions handout for each student
 Air Conditioning System Operations Matching Terms and Definitions Answer Key
 Warm-up Activity (slide 3)
 Air Conditioning System Operations Quiz for each student
 Air Conditioning System Operations Quiz Answer Key
Introduction
The main purpose of this lesson is to help students understand residential (household) air conditioning
systems and terms used in typical residential (household) air conditioning systems.
Ask: Have you ever thought about how important modern air conditioning is to your daily life?
Ask: Have you ever thought about what you would do on a hot summer day if you could not run your home air
conditioner?
4
Copyright © Texas Education Agency, 2013. All rights reserved.
Outline
MI
OUTLINE
NOTES TO TEACHERS
I.
Introduction and start of lesson
A. Bell work activity
B. Warm-up activity
Begin the Air Conditioning
System Operations slide
presentation.
II.
Air conditioning system operations
A. Overview
B. Theory of air conditioning systems
Have students work on the
Bell Work Activity.
(slide 2)
III.
Air conditioning system layout
A. Air conditioning terms
B. System layout
Warm-up Activity: Using Air
Conditioning System
Operations Matching
Definitions handout,
students will work in groups
of two and teach each other
the terms and definitions.
They may do computerbased research to look up
the meaning.
(slide 3)
IV.
Administer quiz at end of lesson
Discuss the theory of air
conditioning; use additional
examples if necessary.
Each slide is meant to be
discussed. Have some
background knowledge and
challenge the students to
make some contributions to
the discussion.
(slides 4-5)
Ensure students understand
the definition and function
of each term. (slide 6)
Carefully discuss the system
layout and the purpose of
each component. (slide 7)
Use answer key to grade the
quiz.
5
Copyright © Texas Education Agency, 2013. All rights reserved.
Multiple Intelligences Guide
Existentialist
Interpersonal
Intrapersonal
Kinesthetic/
Bodily
Logical/
Mathematical
Musical/Rhythmic
Naturalist
Verbal/Linguistic
Visual/Spatial
Application
Guided Practice
Teacher and students search the internet to find different sources to gain more insight into
 Unique ways A/C systems are created and used around the globe
 Companies who use cutting-edge technology to create new A/C systems
Independent Practice
 Students write a 50 word essay on the various kinds of refrigerants used in A/C systems
 Students research the impact of new environmental regulations on the A/C industry online
Summary
Review
Students review the terms from the Warm-up Activity and key points from the Air Conditioning System
Operations slide presentation.
Evaluation
Informal Assessment
Teacher will assess learning through oral questions and answers. Students will discuss terms, definitions, and
key points from the Air Conditioning System Operations slide presentation.
Formal Assessment
Teacher will administer the Air Conditioning System Operations Quiz.
Enrichment
Extension
Students will write a paper about Willis H. Carrier and his contributions to the A/C industry.
6
Copyright © Texas Education Agency, 2013. All rights reserved.
Name______________________________________Date_______________________Class______________
Manufacturing Engineering
Air Conditioning System Operations
Matching Terms and Definitions
Directions: Match the terms in Section 1 with the definitions in Section 2 (next page)
Section 1:
A. 1st Law of Thermodynamics
B. 2nd Law of Thermodynamics
C. British Thermal Unit (BTU)
D. Compressor
E. Condenser
F. Evaporator
G. Heat transfer
H. Refrigerant
I.
Thermal expansion
J. Thermostat
7
Copyright © Texas Education Agency, 2013. All rights reserved.
Section 2:
1. _____ receives the cool pressurized gas from the compressor. The gas absorbs the heat from the
air and cools the air that is blown into the house interior.
2. _____ receives the hot pressurized gas from the evaporator and cools it (with the aid of fans) and
changes it back into a liquid through the condensation process. The liquid is returned to the
compressor to start the process all over again.
3. _____ the flow of heat from one body with higher temperature to another body that has a lower
temperature, until the two temperatures are equal. There must be a temperature difference
between the two materials for heat transfer to take place.
4. _____ a measurement of heat equal to the amount of heat required to raise one pound of water
one degree Fahrenheit.
5. _____ used to pressurize the refrigerant (changes it to a gas) and circulate the refrigerant through
the system.
6. _____ the fluid used in heat transfer in a refrigeration system that absorbs heat by evaporation at
low temperature and pressure and gives up heat on condensing at higher temperatures and
pressures.
7. _____ states that heat always flows from a material with a high temperature to a material with a
low temperature.
8. _____ states that energy cannot be created or destroyed, but can only be changed from one state
to another.
9. _____ senses the air temperature in the evaporator and controls the cooling process by turning the
compressor on and off as needed.
10. _____ an increase in the volume of a material as its temperature is increased.
8
Copyright © Texas Education Agency, 2013. All rights reserved.
Manufacturing Engineering
Air Conditioning System Operations
Matching Terms and Definitions
Answer Key
1. F. Evaporator: receives the cool pressurized gas from the compressor. The gas absorbs the heat
from the air and cools the air that is blown into the house interior.
2. E. Condenser: receives the hot pressurized gas from the evaporator and cools it (with the aid of
fans) and changes it back into a liquid through the condensation process. The liquid is returned to
the compressor to start the process all over again.
3. G. Heat transfer: the flow of heat from one body with higher temperature to another body that has
a lower temperature, until the two temperatures are equal. There must be a temperature
difference between the two materials for heat transfer to take place.
4. C. British Thermal Unit (BTU): a measurement of heat equal to the amount of heat required to
raise one pound of water one degree Fahrenheit.
5. D. Compressor: used to pressurize the refrigerant (changes it to a gas) and circulate the refrigerant
through the system.
6. H. Refrigerant: the fluid used in heat transfer in a refrigeration system that absorbs heat by
evaporation at low temperature and pressure and gives up heat on condensing at higher
temperatures and pressures.
7. B. 2nd Law of Thermodynamics: states that heat always flows from a material with a high
temperature to a material with a low temperature.
8. A. 1st Law of Thermodynamics: states that energy cannot be created or destroyed, but can only be
changed from one state to another.
9. J. Thermostat: senses the air temperature in the evaporator and controls the cooling process by
turning the compressor on and off as needed.
10. I. Thermal expansion: an increase in the volume of a material as its temperature is increased.
9
Copyright © Texas Education Agency, 2013. All rights reserved.
Name______________________________________Date__________________________Class_________
Manufacturing Engineering
Air Conditioning System Operations
Quiz
1. The air conditioning (A/C) process involves ______________________________ within an enclosed
living environment.
2. By creating a mechanical system to ______________________________, we create our modern day
A/C systems.
3. An air conditioning system contains a ______________________________ that circulates through an
enclosed system of tubes.
4. The ideal refrigerant is __________________________________________________ and has high heat
transfer ability.
5. The BTU rating indicates the ______________________________ of air conditioning systems.
6. Currently the air conditioning industry uses _______________________________ refrigerants because
they contain many of the ideal characteristics.
10
Copyright © Texas Education Agency, 2013. All rights reserved.
Manufacturing Engineering
Air Conditioning System Operations
Quiz Answer Key
1. The air conditioning (A/C) process involves controlling air temperatures within an enclosed living
environment.
2. By creating a mechanical system to control heat transfer, we create our modern day A/C systems.
3. An air conditioning system contains a pressurized liquid (refrigerant) that circulates through an
enclosed system of tubes.
4. The ideal refrigerant is non-flammable, non-toxic, non-damaging to the Ozone and has high heat
transfer ability.
5. The BTU rating indicates the cooling capacity of air conditioning systems.
6. Currently the air conditioning industry uses hydrofluorocarbon based refrigerants because they
contain many of the ideal characteristics.
11
Copyright © Texas Education Agency, 2013. All rights reserved.