Manual P - Psychrometrics

Manual PManual P - Psychrometrics

ACCA's Manual P: Psychometrics - Theory and Applications teach HVAC contractors how to find and analyze various types of air properties and how to find the volume of flow rates of air through residential and commercial air conditioning ducts.

Within Manual P, you'll also learn about the basics of Psychrometrics and HVAC systems, how to properly utilize the Psychrometric chart, how to use Psychrometric processes and calculations, how to calculate heating, cooling, humidification, and loads, and how to find room sensible heat ratio, room CFM, and coil sensible heat ratio.


Manual P is divided into five informative sections, with an additional Solutions section that details solutions of tables featured earlier in the Manual.

Section 1 - Understanding and Reading the Psychrometric Chart
Section 1 goes over the Psychrometric Chart, its importance, and how to properly read, understand and utilize it.

  • Introduction
  • Dry Bulb Temperature
  • Specific Humidity
  • Wet Bulb Temperature
  • Relative Humidity
  • Dew Point
  • Enthalpy
  • Specific Volume
  • Summary of Properties
  • Examples
  • Practice Problems
  • Solutions

Section 2 - Psychrometric Processes and Calculations
Section 2 details the properties, processes, and calculations involved in HVAC Psychrometrics.

  • Introduction
  • Sensible or Latent Processes
  • Combined Sensible and Latent Processes
  • Air Side Equations
  • Summary of Process Line Calculations
  • Examples of Psychrometric Processes
  • Mixing
  • Practice Problems
  • Solutions

Section 3 - Room Sensible Heat Ratio and Room CFM
Section 3 teaches you how to find the Room Sensible Heat Ratio and Room CFM.

  • Room Sensible Heat Ratio
  • Room Sensible Heat Ratio Line
  • Design CFM (Room)
  • Selecting Supply Air Temperature
  • Multiple Room Sensible Heat Ratios
  • Summary
  • Practice Problems
  • Solutions to Practice Problems

Section 4 - The Coil Sensible Heat Ratio
Section 4 goes over room design and calculating Coil Sensible Heat Ratio.

  • Coil Sensible Heat Ratio Without Ventilation
  • Coil Sensible Heat Ratio With Ventilation
  • Example - Coil Sensible Heat Ratio With Ventilation
  • Construction of the RSHR and CSHR Lines
  • Example: Construction of the Coil Sensible Heat Ratio Lines
  • Coil By-Pass Factor
  • Practice Problem
  • Solution for Practice Problem

Section 5 - Psychrometrics of HVAC Systems
Section 5 will go over in detail the details of the various other Psychrometric processes that occur within HVAC systems.

  • Psychrometrics for Supply Ducts and Return Air Plenums
  • Psychrometrics for Reheat Systems
  • Variable Volume Systems
  • Multi-Zone and Dual Duct Systems
  • Evaporative Cooling


Throughout Manual P's sections are blank tables and problems for practice purposes. This supplementary section features the solutions to those tables and problems.


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