RE: [EnergyPlus_Support] E+ Lights Object: Fixture spec.

My apologies. You are correct – two Lights objects per zone gives a fatal error. (It shouldn’t!).

From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx]
Sent: Wednesday, October 29, 2014 4:56 AM
To: energyplus_support@xxxxxxxxxxxxxxx
Subject: RE: [EnergyPlus_Support] E+ Lights Object: Fixture spec.

If you input two light objects in the same zone, this will give a fatal error.

Input just one light object, like jim said.

I think this the way.

To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: EnergyPlus_Support@xxxxxxxxxxxxxxx
Date: Tue, 28 Oct 2014 18:13:59 -0400
Subject: Re: [EnergyPlus_Support] E+ Lights Object: Fixture spec.

You could have a separate Lights object for each fixture.

But EnergyPlus aggregates all the lighting power (watts times schedule) at that time step at the zone level. So you can have a single Lights object that aggregates all your light fixtures. Or you could have a Lights object for each type of lighting (with different wattages/schedules).

For example, you could have a single Lights object for all lighting power in the zone:

Lights,

    AllLights,               !- Name

    Zone1,                   !- Zone or ZoneList Name

    OfficeLights,            !- Schedule Name

    LightingLevel,           !- Design Level Calculation Method

    ,                        !- Lighting Level {W}

    0.9,                     !- Watts per Zone Floor Area {W/m2}

    ,                        !- Watts per Person {W/person}

    ,                        !- Return Air Fraction

    ,                        !- Fraction Radiant

    ,                        !- Fraction Visible

    1,                       !- Fraction Replaceable

    ,                        !- End-Use Subcategory

No; !- Return Air Fraction Calculated from

!- Plenum Temperature

Or you can have two objects for each zone -- one each for desk task lights and overhead fluorescent troffers:

Lights,

    Desk Task Light,         !- Name

    Zone1,                   !- Zone or ZoneList Name

    DeskLights,              !- Schedule Name

    LightingLevel,           !- Design Level Calculation Method

    ,                        !- Lighting Level {W}

    ,                        !- Watts per Zone Floor Area {W/m2}

    45,                      !- Watts per Person {W/person}

    ,                        !- Return Air Fraction

    ,                        !- Fraction Radiant

    ,                        !- Fraction Visible

    1,                       !- Fraction Replaceable

    TableLights,             !- End-Use Subcategory

    No;                      !- Return Air Fraction Calculated from

                             !-     Plenum Temperature

Lights,

    FluorescentTroffer,      !- Name

    Zone1,                   !- Zone or ZoneList Name

    OfficeLights,            !- Schedule Name

    Watts/Area,              !- Design Level Calculation Method

    ,                        !- Lighting Level {W}

    0.8,                     !- Watts per Zone Floor Area {W/m2}

    ,                        !- Watts per Person {W/person}

    ,                        !- Return Air Fraction

    ,                        !- Fraction Radiant

    ,                        !- Fraction Visible

    1,                       !- Fraction Replaceable

    OfficeLights,            !- End-Use Subcategory

    No;                      !- Return Air Fraction Calculated from

                             !-     Plenum Temperature

On Tue, Oct 28, 2014 at 4:17 PM, Jim Dirkes jim@xxxxxxxxxxxxxxxxxxxxxxxxxxx [EnergyPlus_Support] <EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:

I am not quite sure what you're trying to do, but E+ doesn't concern itself with lighting fixtures, just watts and usage.

For example, if you have a 4 tube 40 watts / tube fluorescent light fixture, you must use about 4 * 40 * 1.25 watts per fixture so as to include ballast energy. Other fixtures may not have a ballast, etc. E+ doesn't know or care.

On Tue, Oct 28, 2014 at 3:23 PM, 'jeannieboef@xxxxxxxxx' jeannieboef@xxxxxxxxx [EnergyPlus_Support] <EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:

Not to my knowledge. You could check the Lights object fields available in your .idd file, to see if any reference an external fixture object.

Mit freundlichen Grüßen- Sent from my iPhone (excuse the brevity)

i. A.

Jean Marais

b.i.g. bechtold

Tel. +49 30 6706662-23

On 28.10.2014, at 17:12, "Eric Allen Youngson eric@xxxxxxxxxxxxxxxxxxxxxxxx [EnergyPlus_Support]" <EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:

Does anyone know EnergyPlus can specify a lighting fixture object to be referenced by the Lights object?

Thx

--

    Eric Youngson

    eric@xxxxxxxxxxxxxxxxxxxxxxxx

    503 468 7021

    www.successionecological.com

    322 NW 6^th Ave. Suite 200 | Portland, Oregon | 97214

<image001.png>

--

James V Dirkes II, PE, BEMP, LEED AP
The Building Performance Team
1631 Acacia Drive, Grand Rapids, MI 49504
(M) 616 450 8653

The more one does what is good, the freer one becomes. There is no true freedom except in the service of what is good and just.

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