Start with the direct formulas (T_db, RH → all outputs). Then add inverse solving via Goal Seek. Finally, if you find yourself repeatedly computing wet‑bulb or dew point, invest an afternoon in writing VBA functions—you will never need a paper chart again. Word count: approx. 1,950
(SI, kJ/kg dry air )
=B5 * (B4/100) Cell B7:
=0.61094*EXP(17.625*B3/(B3+243.04)) Cell B6:
=1.006*B3 + B7*(2501 + 1.86*B3) Cell B9: psychrometric chart calculator excel
– solved iteratively from ( p_ws(T_dp) = p_w ).
| Known 1 | Known 2 | Solve for → | Method | |---------|---------|-------------|--------| | T_db, RH | All others | Direct | | T_db, W | RH | Inverse via ( p_w = (W \cdot P)/(0.62198+W) ) then RH = 100*p_w/p_ws | | T_db, T_wb | W, RH, h, v | Iterative (solve Carrier equation) | | T_db, h | W, RH, T_wb | Quadratic from enthalpy equation | | T_dp, T_db | RH, W | RH = p_ws(T_dp)/p_ws(T_db) *100 | Start with the direct formulas (T_db, RH → all outputs)
=0.62198 * B6 / (B2 - B6) Cell B8: