lighting load

[p1234567]

Hi,
I have a question regarding the lighting system. for flurescent lighting in a house, I am taking heat gain to be W/m2.
what should we use for dimming profile?
I am getting huge Electric consumption for lighting.
please advice.
appreciate it.

[daki]

The first thing to check is the assigned LPD (lighting power density) values for each space, but I assume you have already done that. Next thing to check is the project profile assigned to those values, i.e. to the lighting gain for each space. The lights may be on continuously which is not a real-world scenario, except for spaces that must have lighting 24/7.
Dimming profiles are used mostly for spaces that have daylight sensor where the LPD would depend on the available daylight in the space.

[Terence]

Following on to the reply from daki, there is an FAQ on our knowledge base that looks at the dimming profile.

https://www.iesve.com/support/faq/pdf/w ... -up-to.pdf

[p1234567]

Thank you for your replies. So, for fluorescent how much do you assign W/m2?
and as for dimming profile, if you set off it goes to zero and if you set as lighting profile it goes too high. I guess it should be attached to the daylighting sensor to turn off when there is light and save in this load. that is what I am working on now.
yet the sensor simulation in radiance is not generating results for the illuminance ( it says geometry of sensor is not matching with the current model)…
any advice.
thanks a lot.

[daki]

Do you have Electrical Installation floor plans? They should show installed lighting (with information about lamps and their power) and you can then calculate LPD by dividing the installed lighting power with the space area. If not then you can use ASHRAE 90.1 values from the mandatory requirements... For Radiance troubleshooting, I can't help you since I had some issues with it as well. The important thing here is to run the model report and have a model without geometry issues...

[p1234567]

thanks for the reply. I guess with the sensor that would put dimming to zero when the daylight level is acceptable that would save. Yet I have a question. as a house with 5-6 zones how can we work on turning only one room on if needed at night for example or would the model work on turning all house on when the level of lux is below the profile control?? is it all the house goes on instead of occupied room having artificial light only?
thanks

[daki]

To properly set up daylight dimming, you need to enable and place sensors in Radiance and then run the Radiance simulation (type: Apache). That will assign each space with sensors an illuminance value that you can then use in a formula for the dimming profile that will basically act as a coefficient for the switching profile. You can create a formula for your dimming profile that would return back values from 0 to 1 depending on the illuminance value, i.e. based on how much daylight there is at any given moment (if there is sufficient daylight then it would return 0 - no lighting gain; if there is not enough daylight it would return a value greater than 0 and up to 1 - dimmed to full-on lighting). I am not sure if I explained this clear enough...

[p1234567]

Hi,
thanks a lot that is very clear and that is what I was doing, yet is there like a control for presence detector? like if in a house with two people, with daylight low illuminance and need for artificial lighting, I need only the room the couple are in to be lit and not the whole house. how to control that only one room is on and not all the house goes on in case of need for artificial light.
thanks a lot
R.K.

[daki]

I am not sure if I follow... There isn't something like a presence detector because IES does not model daily routines of people. You can control the lighting gain for each space separately with a switching profile, combined with a dimming profile. So, let's say the couple is away to work from 9 to 5 during the work week - all spaces are off during this time. Let's say they use the k*****n for 2 hours per day - you can set the lighting switching profile to on for 0.5 h in the morning and 1.5 hours in the evening. And so on... Every internal gain for each space is controlled by a profile. You can set the profiles for each space individually in Apache - Tabular Space Data.

[p1234567]

Yes I know there isn't presence detector in IES. I was wondering if there is a factor that I should include value to work as a presence detector function. for example I saw Diversity factor. in the hours that the couple are at home and the control profile set the lighting on (for example at night), I dont want the whole house lighting consumption . how do I control that? does the diversity factor work on that?
thanks