Join CaptiveAire for a professional development hour (PDH) all about psychrometrics and the Psychrometric Charthow it came to be, how it's used, and why it's important in HVAC design. This topic is particularly helpful for anyone who works in HVAC, especially HVAC engineers and consultants, or anyone who wants to gain a deeper understanding of the world around us. Learn more about CaptiveAire at captiveaire.com.

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0:00 Introduction
0:37 A very brief history of the psychrometric chart
2:15 Part 1 The Fundamentals
3:08 Dry bulb vs wet bulb temperatures
5:47 Relative humidity
9:40 Dewpoint
11:30 Moisture content
13:06 Enthalpy
15:56 Specific volume
17:22 Finding all parameters example
18:53 Part 2 Mapping HVAC Processes
19:06 Basic directions on the chart
21:25 Evaporative cooling and the adiabatic process
22:16 The comfort zone
22:43 The cooling process
25:05 Internal heat gains and the sensible heat ratio (SHR)
27:10 The heating process
28:36 Part 3 Sizing HVAC Equipment
29:42 Sizing Example 1 A simple enthalpy calculation
31:52 Sizing Example 2 Peak dry bulb vs. dehumidification conditions
35:22 Other factors influencing equipment sizing
37:55 Part 4 Modulation, Gas Reheat, and Economizers
37:58 Modulation
40:22 Reheat
43:13 Economizers
46:20 Conclusion