\[\begin{array}{l}{{\dot Q}_{HN}} = konst \cdot {(\Delta {\vartheta _{m,75/65/20}})^n}\\{{\dot Q}_H} = konst \cdot {(\Delta {\vartheta _m})^n}\\{{\dot Q}_{HN}} = {{\dot Q}_H} \cdot {\left( {\frac{{\Delta {\vartheta _{m,75/65/20}}}}{{\Delta {\vartheta _m}}}} \right)^n}\\{{\dot Q}_{HN}} = {{\dot Q}_H} \cdot f\\f = {\left( {\frac{{\Delta {\vartheta _{m,75/65/20}}}}{{\Delta {\vartheta _m}}}} \right)^n}\end{array}\]