Creating a is a game-changer for HVAC engineers and students who need to move beyond manual plotting on paper. By leveraging standard ASHRAE formulas, you can build a tool that instantly calculates air properties like enthalpy, dew point, and humidity ratio based on just two known inputs. Why Use Excel for Psychrometrics?
(Note: Professional engineers often use the more complex ASHRAE formulation for higher precision across wider temperature ranges.) psychrometric chart calculator excel
Because dew point requires solving ( p_ws(T_dp) = p_w ), use Excel’s Goal Seek or implement an inverse approximation. A decent direct approximation (for 0–60°C) is: Creating a is a game-changer for HVAC engineers
The foundation of all psychrometric calculations is the Saturation Vapor Pressure ($P_ws$)—the pressure at which the air is fully saturated. A common empirical formula used in Excel for this is the or equations from ASHRAE. (Note: Professional engineers often use the more complex
[ h = 1.006 \cdot T_db + W \cdot (2501 + 1.86 \cdot T_db) ] where:
To build a basic calculator, you need the fundamental equations for moist air. For best results, use ( kPak cap P a ) or IP units ( psiap s i a ) consistently. 1. Saturation Vapor Pressure ( Psatcap P sub s a t end-sub