[Bldg-sim] ASHRAE 90.1 Baseline LPD and occupancy sensor credit

Jim Dirkes jim at buildingperformanceteam.com
Thu Dec 1 11:27:39 PST 2011


Makes sense (and gets me thinking a bit differently, which is also good.)
Thanks!

 

The Building Performance Team
James V. Dirkes II, P.E., BEMP , LEED AP
1631 Acacia Drive NW
Grand Rapids, MI 49504
616 450 8653

 

From: Steven Savich [mailto:ssavich at systemswestengineers.com] 
Sent: Thursday, December 01, 2011 1:35 PM
To: 'Jim Dirkes'; 'Bldg-Sim'
Cc: 'Nick Caton'
Subject: RE: [Bldg-sim] ASHRAE 90.1 Baseline LPD and occupancy sensor credit

 

Jim,

 

My reasoning for adjusting schedules instead of LPD or actual connected kW
is that it's more transparent for the reviewer, because:

The baseline LPDs == 90.1 required values

Proposed model LPDs or directly input kWs == what is on the drawings

 

You can then have identical "occupancy sensor" schedules in both the models
which is applied where occupancy sensors are required in the baseline
(classrooms, conference, etc), and where occupancy sensors are installed in
the proposed building model.

 

Steven

 

From: Jim Dirkes [mailto:jim at buildingperformanceteam.com] 
Sent: Thursday, December 01, 2011 10:15 AM
To: ssavich at systemswestengineers.com; 'Bldg-Sim'
Subject: RE: [Bldg-sim] ASHRAE 90.1 Baseline LPD and occupancy sensor credit

 

Steven,

Out of curiosity, why do you think it matters that the schedule be adjusted
instead of the LPD? It seems that the end result will be the same.

 

The Building Performance Team
James V. Dirkes II, P.E., BEMP , LEED AP
1631 Acacia Drive NW
Grand Rapids, MI 49504
616 450 8653

 

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Steven Savich
Sent: Thursday, December 01, 2011 12:35 PM
To: 'Ramana Koti'; 'Bldg-Sim'
Subject: Re: [Bldg-sim] ASHRAE 90.1 Baseline LPD and occupancy sensor credit

 

Ramana,

 

90.1-2007 Table G3.1 section 6 under Baseline Building Performance states: "
. . . No automatic lighting controls (e.g. programmable controls or
automatic controls for daylight utilitzation) shall be modeled in the
baseline building design, as the lighting schedules used are understood to
reflect the mandatory control requirements in this standard."

 

You should not be adjusting the power density number to simulate lighting
controls, but adjusting the schedules to reflect occupancy sensor operation.
For example, say there are a number of offices and conference rooms in the
proposed building that will have occupancy sensor controls.  This should be
simulated by inputting the LPD or actual connected load, and creating a
schedule with a 10% - 15% reduction for each hour of operation per Table
G3.2.  In the LEED baseline model, the schedule for the offices would be not
have the occupancy sensor reduction, but the conference room and other
spaces required by 90.1 to have occupancy sensor control would use the
reduced schedule.  Clear as mud?

 

Steven

 

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Ramana Koti
Sent: Thursday, December 01, 2011 8:21 AM
To: Bldg-Sim
Subject: [Bldg-sim] ASHRAE 90.1 Baseline LPD and occupancy sensor credit

 

All,

 

This question pertains to a LEED energy model per the ASHRAE 90.1 Appendix
G. Occupancy sensors are required in spaces such as conference rooms and
employee lunch/break rooms per Section 9.4.1.2 and no lighting power density
credit can be taken for their use in the proposed design model.

 

My question is, do the baseline maximum LPDs prescribed by ASHRAE, say 1.3
W/sf for conference rooms, already account for the power 10 or 15%
adjustment for occupancy sensor use or does the credit have to be manually
applied on top of the 1.3 W/sf in the Baseline model?

 

Thank you,

Ramana Koti.

 

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