Best: Psychrometric Chart Excel

In Excel (for °C):

=610.78*EXP(17.27*T_db/(T_db+237.3)) where T_db is in °C. (Less accurate but fine for HVAC basics.) =0.62198 * P_w / (P_atm - P_w) Where P_w = vapor pressure (Pa) = RH * P_sat / 100. 3. Relative Humidity (RH) from P_w =P_w / P_sat * 100 4. Enthalpy (kJ/kg da) = 1.006 * T_db + W * (2501 + 1.86 * T_db) 5. Wet-Bulb Temperature (iterative in Excel) No direct formula – use iterative calculation or a lookup table. A common workaround: use the psychrometric function from an add-in (see Part 4). Part 3: Plotting a Basic Psychrometric Chart in Excel You can create a constant relative humidity curve for a chart. Step 1: Set up data table | T_db (°C) | RH 10% | RH 30% | RH 50% | RH 70% | RH 100% | |-----------|--------|--------|--------|--------|---------| Step 2: Calculate P_sat for each dry-bulb temp Column A: T_db (0 to 50°C, step 2°C) Column B: =610.78*EXP(17.27*A2/(A2+237.3)) (P_sat in Pa) Step 3: Calculate W for each RH For RH=10%: =0.62198*(0.1*B2)/(101325 - 0.1*B2) psychrometric chart excel

Assume pressure = 101.325 kPa (sea level). Hyland-Wexler equation (simplified): In Excel (for °C): =610

In Excel using Magnus formula: