achieving ashrae 90 plus 30
TRANSCRIPT
BY M A R I A RA M O S , P E , L E E D A P , C X A
ACHIEVING ASHRAE 90 PLUS 30
ABOUT ME
• Employed at Fosdick and Hilmer in Cincinnati• First LEED project in 2007• Performed energy modeling on about 10 LEED
projects• Have achieved platinum, gold and silver status• Use primarily Trace 700 for energy modeling. I
have also used Equest.
AUDIENCE
• What is your experience with LEED?
RESOURCES AVAILABLE FOR GUIDANCE
• ASHRAE Advanced Energy Guidelines• http://aedg.ashrae.org/• Has guides for a variety of buildings, achieving
plus 30 and plus 50% savings
SAMPLE MODEL ASSUMPTIONS
• Midrise Medical Office building, 5 floors, 150,000 SF• Space types: enclosed office, open plan office,
corridor, conference area, exam rooms, operating rooms• Started out with baseline and proposed both
100% ASHRAE compliant (so nothing in the proposed did not meet ASHRAE 90)• 32% glass• System 7s with 95% filtration, ducted return• Hot water boiler, screw chillers
ECM #1
• Increase roof insulation to R-30 and wall insulation to R-15.6 ci• Cumulative savings: 0.2%
ECM #2
• Fenestration improvements, U value of 0.29, SHGC=0.34• Resulted in cumulative savings of 0.61%• Added in sunshades for south facades, but took
them back out because they caused a slight increase in energy usage• Glass ECMs may have a bigger impact on a
different building• What happens when there is an unexpected
result?
ECM #3
• Improve lighting W/SF• Exam rooms, 1.2 (1.66 allowed)• Laboratory, 1.2 (1.8 allowed)• Office, 0.9 (1.1 allowed)• Did not change patient rooms (0.62 allowed), operating
rooms (1.89 allowed), or corridor (0.89 allowed)• Did not include any savings for occ sensors in non-
required areas
• Cumulative savings 1.35%
ECM #4
• Improve HVAC plants• VFD on tower fans• Reduce cooling, heating pumping energy (22 W/GPM
allowed, 19 W/GPM allowed)• HW boiler 90% efficient
Cumulative savings: 3.2%
ECM #5
• Improve chiller efficiency to 0.57 kw/T (need a VFD chiller to accomplish this)• Cumulative savings: 5.4%• A lot more can be done here if your building has
centrifugal chillers
ECM #6
• HVAC—Increase motor efficiency on fans (to 95%)• Calculate kw-cfm/in-wg for each fan• Cumulative savings: 12.5%
ECM #7
• Bring miscellaneous equipment down to around 25% of baseline (by energy usage, not cost at this stage)• Not strictly an ECM, but helps other ECMs have
more impact• Will impact the baseline• Cumulative savings: 14.5%
ECM #8
• Add daylighting with continuous dimming, all exterior rooms in proposed• Cumulative savings: 17%
WHAT TO DO NEXT?
• We’ve exhausted our list from the plus 30 guide• Go to the plus 50 Hospital. Also browse the other
guides• Some other resources:• http://www.i2sl.org/resources/toolkit.html• http://energy.gov/eere/efficiency/buildings
• I’m going to add a few ECMs I’ve used previously
ECM #9
• Reduce airflow in O.R.s at night• Reduce from 20 ACH daytime to 50% at night• Will require tracking boxes on supply, return for
pressurization control• Can be used in labs or other spaces where a high
airchange rate is required by ASHRAE 170• Cumulative savings: 22.8%
ECM#10
• Add heat recovery chiller to proposed• 250 T heat recovery chiller, rejects heat to the heating
plant• Cost
Cumulative savings: 26.0%
OTHER POTENTIAL ECMS
• Separate OA treatment• Energy recovery• Use energy star rated computers, etc and take
credit for it in the W/SF receptacle density• More efficient elevators (trackless), take credit for
it in the miscellaneous loads
MINOR REFINEMENTS
• Custom unloading curves• Raise chilled water temps if you can (and use
improved chiller kw/T)• Calculate out actual u value of window assy• Consider exterior lighting savings• Increase supply air reset by 1 degree
LEED/HIGH ENERGY SAVINGS PROCESS
Development of
Schematic Energy Model
•Identify and evaluate major cost impact items, i.e. Daylighting sensors, LED lights, Heat recovery chiller, improved glass or insulation. Contractor input very helpful for pricing.
DD/CD
•May have to create an energy model before rooms are known. This model will be “throw away”
Major cost impact items
Construction•Energy model assumptions are documented in submittals
• Refine equipment selections, make sure any model assumptions are reflected in bid docs
QUESTIONS?