Here is a PDF of a PowerPoint presentation that I did for our Project Engineers to go over the basic concepts of Motor Circuit Over Current Protection for HVAC related equipment.
This is where I discuss the concept of VAPOR PRESSURE in detail. Vapor Pressure is without any doubt the most important psychrometric property that needs to be understood for the HVAC engineer trying to learn psychrometrics. It is bizarre that many students are going through “Psychrometric Chart” training without even talking about Vapor Pressure. The fact that ASHRAE chose not to show this property on their standard chart may have something to do with this trend. You can “draw process lines” on the charts without any mention of Vapor Pressure but the penalty you pay is a loss of key underlying psychrometric concepts.
As usual conversion from PowerPoint to PDF and no narration leaves out a lot. But I think the following will still be very helpful to new engineers.
Please send in your comments and corrections to me. Thank you.
Here is Part-2, which describes the “Integral” component of the PID control. Some diagrams need a little work, and will be updated a little later.
Please open the pdf below and then come back here for comments: