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Cooling Fundamentals Course SS102 Series

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Cooling Fundamentals Course SS102 Series HVAC Essentials Cooling Fundamentals Course SS102 Series ® Course SS102 Cooling Fundamentals Version 2.1 2013 HVAC Learning Solutions Page 1 of 56 HVAC Essentials Cooling Fundamentals Course SS102 Series Table of Contents 1. Basic Concepts ..................................................................................................... 4 1.1. Energy .......................................................................................................... 4 1.2. Heat .............................................................................................................. 5 1.3. Temperature ................................................................................................. 5 1.4. Cold .............................................................................................................. 7 1.5. BTU (British Thermal Unit) ........................................................................... 7 1.6. BTUH (BTUs per Hour) ................................................................................ 8 1.7. Specific Heat ................................................................................................ 8 1.8. Sensible Heat ............................................................................................... 9 1.9. Heat Flow ................................................................................................... 10 2. Methods of Heat Transfer ................................................................................... 11 2.1. Conduction ................................................................................................. 11 2.2. Convection ................................................................................................. 11 2.3. Radiation .................................................................................................... 13 3. Energy & Heat Transfer Quiz .............................................................................. 14 4. Forms of a Substance ......................................................................................... 19 4.1. Substances and the Change of State ......................................................... 20 5. Forms of a Substance Quiz ................................................................................ 29 6. Pressure ............................................................................................................... 33 6.1. PSI .............................................................................................................. 33 6.2. Pounds per Square Foot (lbs per sq ft) ....................................................... 34 6.3. Inches of Mercury (" of HG) ........................................................................ 35 6.4. Inches of Mercury Vacuum ......................................................................... 35 6.5. Microns ....................................................................................................... 36 6.6. PSIA: Pounds per Square Inch Absolute ................................................... 37 6.7. PSIG: Pounds per Square Inch “Gauge” ................................................... 37 6.8. Vacuum ...................................................................................................... 38 6.9. Compound Pressure Gauge ....................................................................... 38 7. Refrigerants ......................................................................................................... 39 7.1. Characteristics of a Good Refrigerant ........................................................ 39 7.2. Refrigerant Families ................................................................................... 40 Version 2.1 2013 HVAC Learning Solutions Page 2 of 56 HVAC Essentials Cooling Fundamentals Course SS102 Series 7.3. Replacement Refrigerants .......................................................................... 44 7.4. Zeotropic Refrigerants ................................................................................ 44 7.5. Azeotropic Refrigerants .............................................................................. 44 7.6. R-410A ....................................................................................................... 45 7.7. Refrigerant Timeline ................................................................................... 46 8. Fundamentals of Air Conditioning..................................................................... 47 8.1. The Evaporation Process ........................................................................... 47 8.2. The Compression Process ......................................................................... 48 8.3. The Condensing Process ........................................................................... 49 9. Pressure, Refrigerants, and Air Conditioning Quiz .......................................... 51 Appendix: Answers to Quiz Questions .................................................................... 55 Section 3 ............................................................................................................... 55 Section 5 ............................................................................................................... 55 Section 9 ............................................................................................................... 55 Version 2.1 2013 HVAC Learning Solutions Page 3 of 56 HVAC Essentials Cooling Fundamentals Course SS102 Series 1. Basic Concepts 1.1. Energy Energy is the ability to do work. There are thousands of forms of energy. However, they all fall into three fundamental classifications. 1.1.1. Potential Energy Potential Energy is energy that is stored in some form, waiting to be used. For example: A heavy object that can fall or roll downhill. A river that has been dammed up 1.1.2. Kinetic Energy Kinetic Energy is energy in motion that is doing work. A heavy object rolling downhill. A river that is flowing. Potential Energy: stored energy waiting to be used Kinetic Energy: energy in motion Version 2.1 2013 HVAC Learning Solutions Page 4 of 56 HVAC Essentials Cooling Fundamentals Course SS102 Series 1.1.3. Heat Energy Heat Energy is molecules in motion. Molecules within a substance are continuously moving. The hotter a substance is, the faster the molecules move. When a substance reaches absolute zero, the molecules stop moving. Heat Energy: molecules in motion 1.2. Heat Heat is a form of energy that cannot be created or destroyed. All matter that exists on earth is currently in some form. The heat contained within that matter can be transferred from one place to another through the process of "Heat Transfer." Later in this section we will look at the concepts of heat transfer that are widely used in the HVAC industry. 1.3. Temperature Temperature measures the "level" of heat within a substance or medium. The molecular motion within a substance increases as the temperature increases; therefore, the temperature of a substance represents the speed in which the molecules are moving. Temperature alone cannot be used to indicate the total quantity of heat within a substance. It can only be used to measure the" level" of heat. Just because one substance is hotter than another doesn’t necessarily mean it contains a higher quantity of heat. This section will explain how this works. Version 2.1 2013 HVAC Learning Solutions Page 5 of 56 HVAC Essentials Cooling Fundamentals Course SS102 Series 1.3.1. Temperature Scales The Fahrenheit and Celsius temperature scales are illustrated below. Each scale has an absolute scale as its counterpart that is used in science and engineering. 1.3.2. Converting Temperatures The basis for conversions from Fahrenheit to Celsius, and vice-versa, relies on the difference between the freezing and boiling points. In the English system, there is 180° difference (212° - 32°), and in the Metric system there is a 100° difference. This establishes a ratio of 1.8:1 (1.8°F to 1°C). The following formulas can be used to convert these temperatures. Converting from Fahrenheit to Celsius: (F-32) = C 1.8 So, for example, to convert a room temperature of 75°F to degrees C: (75-32) = C 1.8 43 = C 1.8 C = 23.9 Version 2.1 2013 HVAC Learning Solutions Page 6 of 56 HVAC Essentials Cooling Fundamentals Course SS102 Series Converting from Celsius to Fahrenheit: F = (1.8 x C) + 32 So, for example, to convert a room temperature of 25°C to degrees F: F = (1.8 x 25) + 32 F = 45 + 32 F = 77 1.3.3. Absolute Zero Absolute zero is defined as the temperature at which there is no more heat within a substance or medium. At this point, all molecules within a substance stop moving. In theory, absolute zero is the coldest possible temperature that can be obtained. It has been calculated at -460° F or -273° C. Laboratory tests have come close to this point but have never reached it. 1.4. Cold Technically, based on what was just said above, if cold is defined as “the absence of heat,” then it’s not COLD until - 460° F. However, for practical purposes, “cold” is a relative term that is used as a comparison. Since there is no measurement scale for cold, it is best described as the relative absence of heat. 1.5. BTU (British Thermal Unit) The "BTU" is the standard for measuring the quantity of heat being transferred. One BTU has been established by monitoring the amount of heat that is necessary to raise one pound of water one degree Fahrenheit. This equation refers only to the quantity of heat being
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