Annual Daysim Lighting Profile with Manual On/Off control "0": schedule has fractional values

daylight

#1

Hi everyone!

I was trying to create a schedule for EnergyPlus based on HB Annual Daylight simulation, having the lighting control type set to “0” for manual on/off switch. I used Mostapha’s script for Integrated Daylight and Energy from Hydra as a guideline.

My problem is that the manual on/off schedule, as I understand it, should only have values for ‘on’ = 1 and ‘off’ = 0, but I get occasional fractional values in the resulting AnnualProfile schedule (see image attached). Is this expected to happen?

I am also wondering what is the logic behind this lighting control type.
Q1: There is a sensor point but no illuminance threshold assigned, so what are the criteria for users switching lights on/off?
Q2: What is the user’s reaction time and behaviour patterns in responding to the lighting conditions?

Big thanks in advance for your help,
Aga


#2

This comes from the way the lightswitch algorithm is designed. The algorithm assumes the following scenarios;
Lighting Control | Blind Control | User Behavior
active | active | User uses electric lighting in accordance with the need only
passive | active | User keep electric lights on and uses blinds when needed
active | passive | User keep electric lights when needed and keep the blinds closed
passive | passive | User keep electric lights on and keeps the blinds also closed

now there’s no way to know what is the probability of any one of the behavior happening at a particular hour. Therefore, all the four scenarios are considered and the average lighting energy use for the hour is defined. I believe this is the reason you are seeing floats (not whole numbers).


#3

Thanks a lot @devang ! :slightly_smiling_face:

Now if I am not mistaken, this Daysim algorithm is based on a research done by Christoph Reinhart that can be found in his publication Lightswitch-2002: a model for manual and automated control of electric lighting and blinds. Posting it here if anyone is looking for a reference.