hello everyone!

I just wanted to calculate the amount of radiation on a surface by using ladybug radiation analysis… the unit i need is kw/m2 but the output of this component is kwh/m2 … is there any solution that i can convert it to kw/m2? or any component in ladybug or honeybee? thanks

@math202, you can divide the kWh by the number of measurement hours to convert to its average kW.

Note that the distinction between energy and power is important. The kWh is a unit of energy, while the kW is the derivative of energy with respect to time: the rate of energy per unit time. An analogy would be energy is like distance travelled (100 km), while power is like speed - the rate of that distance (100 km/hr) - whose average can be calculated by dividing distance by time. Also note that you can only calculate the average speed this way, even though the actual speed may vary over the course of the trip - same for deriving power from energy with only total kWh and time.

So 1 kWh means we are sustaining a constant rate of 1 kW per hour. If that 1 kWh is measured over one hour, then the average power is 1 kW, but if it’s over ten hours, then it’s average power is 0.1 kW. Since it looks like your analysis output is measured hourly, your kWh is equal to its kW (X kWh / 1h = X kW).

thanks Saeran for ur very helpful response…

so if I want to calculate the kw/m2 I have to divide to 10 hours of sunshine… right?

is there any component that exactly gives me the kw/m2 ? …

Thank ya anyway Dear

I’m not sure if there’s a component that does that conversion. But yes, you can easily use Grasshopper to automatically divide your total energy/m2 by total analysis time ~~(not just hours of sunshine)~~[1] to get average power/m2.

[1] Correction: On second thought, as long as you keep your energy values consistent with your sunshine hours, there’s nothing wrong with using hours of sunshine. This is also a good example of why it’s better to do this calculation manually then through a blackbox component - the value of power is a function of it’s time period, and there isn’t a fixed definition of what an appropriate time is, it depends on the application.