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ceck
Posts: 91
Location: Padova |
 Posted: Thu Feb 14, 2008 10:56 am Post subject: Problems with Lightning energy |
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Hi,
I've found this bug: the Lightning energy (in "Lightning-General Lightning") is not updated automatically when the "Target illuminance" in the activity window is changed. This causes a lot of mistakes in calculating ligtning energy consumption in projects with many zones of different.
So there are two possible solutions:
a) you should update the Lightning energy value
b) show Lightning energy level expressed as W/(m2 100lux) and make an internal calculation of the energy considering the target illuminance. This will be clearer to me...and more correct for the tree structure of the program. In this way zones with different target illuminance would have the same Lightning energy level expressed as W/(m2 100lux)
Regards
Luca
Last edited by ceck on Mon Feb 18, 2008 8:54 am; edited 1 time in total |
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bhandari
Posts: 120
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| Posted: Fri Feb 15, 2008 2:49 pm Post subject: |
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Luca,
I don't think it is a bug. The Target Illuminance in the activity window is the illuminace setpoint for the daylighting calculations and it works only when you switch the Lighting control ON in the lighting energy window. Whenever the lux level in a zone exceeds this set point value, the General lighting will be dimmed (or switched off - depending on the type of control selected). I hope it answers your question.
regards,
Mahabir |
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ceck
Posts: 91
Location: Padova |
| Posted: Mon Feb 18, 2008 8:51 am Post subject: Re: Problems with Lightning energy |
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Mahabir,
thank you nevertheless there is a bug. It is true that target illuminance is used for ligtning control but even if this control is off, target illuminance is used to set the Lightning energy level of each zone.
The Lig. energy is obtained multipling the target illuminance (lux) for the output [lux /(m2*100lux)] of the lightning template. If lightning control is off, this energy consumption is kept constant if lights are on...so the problem is emphasized.
Try this
1) Chose a zone
2) fix a certain lightning template (i.e. T12) and read the Lig. energy
3) double the target illuminance
4) read the Lig. energy, it will be the same of 2)
5) Change light template (i.e. T8 )
6) Go back to T12 light template
7) read the Lig. energy, it will be double of 2)
Regards
Luca |
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Steve Potter
Posts: 572
Location: newcastle |
| Posted: Mon Feb 18, 2008 9:38 am Post subject: |
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Hi Luca,
Currently the General Lighting-Lighting Energy is only calculated using the target illuminance when you initially load a lighting template. The target illuminance and lighting energy are intended to be modified independently so that after loading the template, subsequent modification of the target illuminance doesn't affect the lighting energy but we will consider modifying this behaviour, perhaps using an option to link the variables.
Regards,
Steve
Last edited by Steve Potter on Mon Feb 18, 2008 10:44 am; edited 1 time in total |
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ceck
Posts: 91
Location: Padova |
| Posted: Mon Feb 18, 2008 10:44 am Post subject: |
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Hi Steve,
In my first e-mail I was underlining that the program doesn't update "actual lighting casual gain" when the target illuminance of the zone is changed.
So
| Quote: |
Note that when you load lighting data from template, the actual lighting casual gain is calculated by dividing the W/m2/100 lux data in the template by the required illuminance level as set on the Activity tab.
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should be done not only when the template is loaded but also when the target illuminance is changed.
If I chose T12 lights I want to use T12 lights...so I want to consume a certain number of W/(m2100lux) 
But the best solution in my opinion is the B) one in my first post...use "actual lighting casual gain" in [W/(m2100lux)], clearer, simpler, no "tree" structure problems, doesn't cause mistakes.
Trust me, I've tried this with 50 students and a lot of them had problems of wrong lighting consumptions...they had cet certain templates but the gain was different from what they expected!
Regards
Luca |
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Steve Potter
Posts: 572
Location: newcastle |
| Posted: Mon Feb 18, 2008 10:48 am Post subject: |
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Hi Luca,
You responded rather too quickly to my answer  Please take a look at my modified response. We'll consider ways of improving this behaviour.
Regards,
Steve |
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ceck
Posts: 91
Location: Padova |
| Posted: Mon Feb 18, 2008 10:53 am Post subject: |
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| Steve Potter wrote: | Hi Luca,
but we will consider modifying this behaviour, perhaps using an option to link the variables.
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this would be perfect...and I think not so heavy on the programming side...I hope!
Thanks!
Luca |
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adfc
Posts: 45
Location: Montemerlo |
| Posted: Tue Feb 26, 2008 11:02 am Post subject: |
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| Steve Potter wrote: | | The target illuminance and lighting energy are intended to be modified independently so that after loading the template, subsequent modification of the target illuminance doesn't affect the lighting energy |
I too am a student and I am working with DesignBuilder for my graduation thesis, so I was very interested in this discussion.
I did not notice the behaviour described by Luca, but I think it is really a bug: in fact I do not understand why I would decide to modify independently the target illuminance and lighting energy.
I agree with the Luca's B solution. |
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