Sensible Heat Ratio / Latent Split (ASHRAE)
Field tile: given total cooling Btu/hr, return-air dry / wet-bulb, supply dry-bulb, CFM, and altitude, returns sensible / latent split (1.08 / 4840 coefficients with altitude correction), SHR, and return / supply humidity ratios (grains/lb). Companion to the shr tile which takes both Q values directly. Per ASHRAE Fundamentals 2021 Ch. 1 / Ch. 18.
Formula and source
Q_sensible = 1.08 * CFM * (T_ra - T_sa) * (rho/rho_sea). Q_latent = Q_total - Q_sensible. SHR = Q_sensible / Q_total. W from dry-bulb / wet-bulb via ASHRAE Fund Ch.1 eq. 35: W = ((2501 - 2.326*T_wb_C)*W_s_wb - 1.006*(T_db_C - T_wb_C)) / (2501 + 1.86*T_db_C - 4.186*T_wb_C). dW = Q_latent / (4840 * CFM * rho_ratio). W_sa = W_ra - dW. Altitude correction P(z) = 101.325 * (1 - 2.25577e-5 * z_m)^5.2559.
ASHRAE Fundamentals 2021 Chapter 1 (psychrometrics) and Chapter 18 (nonresidential cooling and heating load calculations).
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