Latent Heat

Latent heat, abbreviated as \(Q_l\), is the energy absorbed or released by a substance during a constant temperature or phase change from a solid to liquid, liquid to gas or vise versa.

 

Latent Heat Formulas
\(\large{ Q_l = \frac{Q}{m}  }\) \(\large{ Q_l = 0.68 \; cfm \; \Delta gr  }\)     (HVAC) btu/hr
Symbol	English	Metric
\(\large{ Q_l }\)  = latent heat of a substance	\(\large{\frac{Btu}{lbm}}\)	\(\large{\frac{kJ}{kg}}\)
\(\large{ cfm }\)  = cubic feet per minute	\(\large{\frac{ft^3}{min}}\)	\(\large{\frac{m^3}{min}}\)
\(\large{ \Delta gr }\)  = grains/lb differential	\(\large{\frac{gr}{lbm}}\)	\(\large{\frac{mg}{kg}}\)
\(\large{ m }\) = mass of the substance	\(\large{lbm}\)	\(\large{kg}\)
\(\large{ Q }\) = amount of energy transferred for the phase change	\(\large{lbf-ft}\)	\(\large{J}\)