How are radiator outputs calculated?

Heatpunk calculates actual radiator outputs with the below formula. This allows us to easily consider differences in flow, return and room temperatures.

P = P₅₀ [((t_i - t_r) / ln((t_i - t_a) / (t_r - t_a))) (1 / 49.32)] n

\documentclass{article}
\begin{document}

\[ P = P50 [((ti - tr) / ln((ti - ta) / (tr - ta))) (1 / 49.32)] n ]

\[ x^n + y^n = z^n \]

\end{document}

where

P = heat emission from radiator (W, J/s)

P₅₀ = heat emission from radiator with temperature difference 50 ^oC (W)

t_i = water temperature inlet (^oC)

t_r = water temperature outlet (^oC)

t_a = surrounding air temperature (^oC)

n = n coefficient

The other way you can calculate radiator outputs is by calculating the correction factor based on temperature differences and the specific radiator being used. To calculate the correction factor you should use mean water temp - ambient temp divided by the dTbelow toformula. the

power

of

where

the

P₅₀ n-coefficient.and Youn wouldare thenas multiplyabove

that

t_rad by= the P50 output of themean radiator you will use.temperature

t_room = room temperature

d_T = design temperature

In the room breakdown of Heatpunk it should give you the total heat loss of the room and then radiator outputs will be calculated based on the flow temp you have used. The rads built into the software are based on Stelrad classic compactcompact, so if you are using anythingheat that'semitters where the outputs differ significantly you should add them in as a custom radiator to ensure the outputs are calculated correctly.