Dimming Lights ( IES-VE)

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Dear all,

Does anyone have an idea to place a dimming light(s) in an IES-VE model?
The artificial light has to supplement the available day lighting to
achieve (500 Lux ) in the space. The dimming light has to be linked to
the Apache Sim, so that the light electricity consumption will show up
in the simulation results. Your step-by-step guidance is highly
appreciated. Many thanks

Best Regards,

Fawwaz Hammad

Hammad, Fawwaz's picture
Joined: 2011-10-02
Reputation: 0

In Radiance (in the appropriate rooms):

1. Set appropriate properties for the glazing, walls, ceilings and
floors. Take care with the Radiance glazing parameter 'transmissivity',
which is not the same as transmittance. Radiance provides a utility for
converting between the two. The transmittance should be set to match the
normal incidence light transmittance from the glazing manufacturer.
Apply a factor for the frame (Radiance doesn't do this automatically).

2. Create daylight sensors.

3. Run the 'Apache' daylight simulation to create the illuminance (.ill)

In Apache View:

1. Set up an appropriate formula profile to control electrical lighting
as a function of working plane daylight illuminance e1 (note that e2 is
not currently available). Create weekly or annual profiles using this
daily profile, as appropriate. An example profile is given in the ApPro
User Guide (and other manuals):

ramp(e1,0,1,500,.4) a formula suitable for applying as a dimming profile
controlling lighting gain as a function of available daylight. It
modulates the lighting gain as a function of the illuminance on the
working plane, e1. The value of the profile falls from 1 at zero
illuminance to 0.4 at illuminance 500 lux, thereafter remaining constant
at this value. The value 0.4 (which you should set as appropriate)
represents the fraction of the room's lighting gain which is not subject
to daylight control. The illuminance e1 must be computed using the link
to Radiance.

Use different formulae as necessary to cater for conditions in different

2. Apply this profile as a dimming profile in the room or rooms.

3. Run ApacheSim with the Radiance link turned on.

4. View lighting gains (turn on the 'sensible internal gains breakdown'
output group in the ApacheSim dialog) and e1 values in Vista.

Rashmi Sonal, LEED AP

Rashmi Sonal2's picture
Joined: 2011-10-02
Reputation: 0


Just a detail to add,

If you have any layer turn off, turn it on for the radiance calculation
and once completed turn it back on for the Apache calc, otherwise you ll
see an error message.



Guin, Michael's picture
Joined: 2011-09-30
Reputation: 0