Radiation Calculation

In the previous example Hourly Simulation we assumed that the radiaiton and illuminance trasmitting through the windows were known. This example explains how this value can be calculated

Import Classes

from radiation import Location
from radiation import Window 

Initialise the Location with an EPW (energy plus weather file)

#Initialise the Location with a weather file
Zurich = Location(epwfile_path=os.path.join(mainPath,'auxillary','Zurich-Kloten_2013.epw'))

Weather files can be donwloaded from the energy plus website

Calculate the sun position

hoy = 3993 #Hour of the year #9:00 am 16 June
#Determine the solar azimuth and altitude angle 
Altitude, Azimuth = Zurich.calc_sun_position(latitude_deg=47.480, longitude_deg=8.536, year=2015, hoy = hoy)

Define the windows

SouthWindow = Window(azimuth_tilt=0, alititude_tilt = 90, glass_solar_transmittance=0.7,
		 glass_light_transmittance=0.8, area = 1) 
EastWindow = Window(azimuth_tilt=90, alititude_tilt = 90, glass_solar_transmittance=0.7,
		 glass_light_transmittance=0.8, area = 1)
WestWindow = Window(azimuth_tilt=180, alititude_tilt = 90, glass_solar_transmittance=0.7,
		 glass_light_transmittance=0.8, area = 1) 
NorthWindow = Window(azimuth_tilt=270, alititude_tilt = 90, glass_solar_transmittance=0.7,
		 glass_light_transmittance=0.8, area = 1)  
RoofAtrium = Window(azimuth_tilt=0, alititude_tilt = 0, glass_solar_transmittance=0.7,
		 glass_light_transmittance=0.8, area = 1) 

Here an azimuth tilt of 0 is the south facing position, east is 90

An altitude tilt of 90 is a vertical window, and 0 is a horizontal

Calculate Solar Gains and illuminance through the window

### Loop through all windows
for selected_window in [SouthWindow, EastWindow, WestWindow, NorthWindow, RoofAtrium]:
	selected_window.calc_solar_gains(sun_altitude = Altitude, sun_azimuth = Azimuth, 
									normal_direct_radiation= Zurich.weather_data['dirnorrad_Whm2'][hoy], 
									horizontal_diffuse_radiation = Zurich.weather_data['difhorrad_Whm2'][hoy])
	selected_window.calc_illuminance(sun_altitude = Altitude, sun_azimuth = Azimuth, 
									normal_direct_illuminance = Zurich.weather_data['dirnorillum_lux'][hoy], 
									horizontal_diffuse_illuminance = Zurich.weather_data['difhorillum_lux'][hoy])

Extract Data

# Solar Gains incident on the window
print SouthWindow.incident_solar # [W]

#Solar gains transmitted to the building
print SouthWindow.solar_gains #[W]

#Illuminance incident on window
print SouthWindow.incident_illuminance #[lumens]

#Illuminance Transmitted through window
print SouthWindow.transmitted_illuminance #[lumens]