Is longwave radiation calculated?


I would like to know if long wave radiation emitted and reflected from the environnement is calculated when doing a radiation analysis on a building ? If yes, where can I see which model is used ?

Thanks a lot for your responses.


You are going to have to be more specific since the number of components that deal with “radiation” are in at least the double-digits. Some of them deal with only incident shortwave radiation, others deal with incident + reflected shortwave radiation, and a few include some longwave radiant exchange models. Which components are you using and what is the metric that you are wondering if it includes long wave radiant exchange?

As I am learning LBT, I am using Ladybug Radiation Analysis, it was the easiest one. I am doing simulations on urban islands. But I need to take into consideration longwave radiations and I would like to know if the radiation analysis components on ladybug (or maybe on honeybee) are doing it.


So, if you actually need to compute the change in air temperature that results from urban heat island, you can use dragonfly-legacy to morph a rural EPW to an urban EPW. This will use the Urban Weather Generator (UWG), which performs a whole energy balance calculation between the land surface, the sky, and the atmosphere to estimate the change in air temperature.

Otherwise, if you are just looking for a metric that relates to how quickly surfaces radiate heat to a cooler sky at night (often the primary cause of the urban heat island effect), you can just run a sky view study like you see in this example file:

Hello Chris, thanks for your time.

In fact, what I am trying to do is to simulate external exchanges between a building and its environment (urban islands for example).

It is a research project, and I have to take into consideration the longwave radiation (from the sky vault, the ground and the surroundings), which is not the case actually in many codes according to several reviews : Simulating external longwave radiation exchange for buildings, Modelling the radiative exchanges in urban areas: A review.

So I would like to know if some components more recent might be taking this into consideration or otherwise on which tool (ladybug, honeybee, dragonfly) do you think it will be efficient to try to implement some code or plug-in to take this radiation into consideration ?

Sorry for the long post, thank you.