|
View previous topic :: View next topic
|
| Author |
Message |
bharat
Joined: 07 Feb 2008
Posts: 12
|
 Posted: Wed Apr 30, 2008 9:59 pm Post subject: LPD value for Residential Buildings |
    |
|
Can anyone please advise if the lighting power density for a residential flat or apartment is required to comply to a certain maximum value and what that value is?
As, according to Ashrae 90.1-2004 section 9.1.1 exempts living units from its scope and therefore there is no provision for residential flat or apartment in Tables 9.5.1 (Building Area Method) and 9.6.1 (Space-by-Space Method). The calculation of the interior lighting power allowance for a residential flat or apartment cannot therefore be performed.
_________________
Bharat
Architect, LEED AP |
|
| Back to top |
|
 |
joelmckellar
Joined: 31 May 2006
Posts: 75
Location: Charleston, SC
|
| Posted: Wed May 14, 2008 2:11 pm Post subject: |
|
|
I could explain, but I'll let the CIR do the talking:
2/23/2007 - Credit Interpretation Request
Our project is a multiple building high-end condominium-resort project. This question relates to the requirements of lighting as it pertains to ASHRAE/IESNA 90.1-2004.
In ASHRAE 90.1-2004, section 9.1.1, exceptions (b) lists that this section does not apply to lighting within living units. However table 9.5.1 Lighting Power Densities Using the Building Area Method lists "Multi-family" building area type with a 0.7 W/SF.
Please clarify for the purposes of EAp2 and EA credit 1, the applicable interpretation of the Standard. Does the entire building have to meet the 0.7W/SF requirement as an average?
3/23/2007 - Ruling
The applicant is requesting clarification regarding which lighting is included in the allowable lighting power density for high-rise multifamily residential projects. All common areas and support areas including circulation, lounges, lobbies, etc. should be included in the lighting power density calculations. Therefore, when using the Building Area Method, the average lighting power density for common areas and support spaces in a high-rise condominium project should be modeled as 0.7 Watts/sf in the Baseline case; or when using the prescriptive compliance methodology, the average lighting power density for these spaces should not exceed 0.7 Watts/sf. Dwelling units are excluded from the allowable lighting power density.
For EA credit 1, the exception listed in Table G3.1.6 states that lighting in multifamily guest rooms which are connected via receptacles and are not shown on the building plans should be modeled identically in the Baseline building and Proposed building simulations, but should be excluded (in post-processing) when calculating the Baseline building performance and Proposed building performance.
For EA credit 1, all hard-wired lighting in living units that is shown on the building plans should be modeled identically in the Baseline and Proposed building simulations as shown in the plans. This lighting shall be considered process energy.
Credit may be taken for an efficient lighting design in the living unit using the Exceptional Calculation Methodology shown below.
(1) Assumptions used as a baseline for residential lighting will need to be supported by specific study results if you propose to include residential lighting savings in the energy performance calculations. These studies will need to address both light density AND daily duty cycle. The maximum allowable baseline for such residential lighting is restricted to 2 W/sf.
(1) Although residential lighting density is higher than offices, the duty cycle of these lights is much lower than in offices. Some studies suggest figures near 2 hours a day or less for hard-wired residential fixtures. This reduces the significance of residential lighting in the energy model.
(2) Baseline lighting assumptions should not include 'portable' light fixtures, nor should the baseline calculations assume use of hard-wired fixtures in rooms where the studies cited indicate portable lights are the norm. Therefore applying a factor of 2 w/sf to the entire residential floor area, even though only three rooms would be anticipated to have hard-wired fixtures, would be inappropriate. In other words, lighting credit can only be taken in rooms where permanently installed hard-wired lighting fixtures can meet the illumination requirements for the room.
(3) In residential units which are heating-load driven, there is an energy offset penalty of approximately 40% (according to numerous Pacific Northwest studies) for reductions to residential lighting load. That is, 4 of every 10 watts saved by reduced lighting loads must be made up for by increased heating energy. This offset must be accounted by your model.
(4) Use of residential lighting energy savings to achieve LEED credit represents an exceptional calculation methodology outside of the LEED modeling protocol. As such it will be carefully scrutinized with respect to baseline and performance claims, and clear and concise documentation will be expected. The energy submittal template must account for this measure using the Exceptional Calculation Methodology.
_________________
Joel McKellar, LEED AP
http://www.reallifeleed.com/ |
|
| Back to top |
|
|
|
blogger
del.icio.us
digg
slashdot
