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Land Community Transportation ion
Students Waste Water Buildings Energy
Deep retrofits: You get what you pay for
Leslie Kramer, Stanford University and Jonathan Schoenfeld, kW Engineering
June 17, 2014
Whole Building Energy Retrofit Program
• Deep retrofits in highest energy using buildings on campus
• Maximizes energy savings in each building within cost-effectiveness criteria
• Looks at a package of measures: no cream skimming
• Big payoffs from in-depth energy audit, advanced control strategies, and relentless performance testing.
WBERP Process
Supplemental and Pre-
Construction Studies
ConstructionCommissionin
g
Phase 1&2
Studies
Bid Docum
ents
Construction
& Commissionin
g Suppor
t
M&V Report
Consulting Engineers
Contractors
Review
Studies
Construction
and Commissioni
ng Suppo
rt
1st Year
Tuning and
Monitoring
Persistence
Tracking
Achieve ROI
Stanford Team
• Savings of $3.5 million per year to date• Total cost $14.6 million to date• PG&E rebates of $2 million• Overall simple payback period under 4 years
Results
Case Study: Packard
• $400,000/year energy cost• 3 stories and a basement• Faculty and grad student offices
and dry labs• Built in 2000• Chilled water, steam and electricity
from Stanford’s central plant• 122,500 gross square feet• 4 Air Handlers, 212 VAV boxes• 12 fan coils for additional cooling• VAV boxes controlled by pneumatic thermostats• DDC control of air handlers
INITIAL BASELINE CONDITIONS: NOT BAD!
Energy Audit Process
ASHRAE Level I Rough savings estimates Go/No-Go decision for measure
analysis
Level II (Measure Analysis) Limited trend review Calibrated eQUEST Model
-
20,000
40,000
60,000
80,000
100,000
120,000
140,000
160,000
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Elec
tric
ity
Usa
ge (k
Wh)
Billing Data
Model Output
Audit Findings
No-cost Measures Increase zone setpoints for unoccupied rooms Schedule how water pumps
Low-cost Measures Daylighting controls Eliminate air handler heating coil operation
when economizing
Zone Level DDC Conversion Deadband thermostats Pressure and Supply Air Temperature Resets Zone scheduling and override
Zone Level DDC Implementation Options
Design-Bid-Build Develop request for proposal (RFP) for design Develop design documents Bid construction
Design-Build Develop RFP Bid design-construction
Design-Assist with Performance Specification Energy consultant develops performance specification Bid design-construction
Performance Specification Development
• Input from Multiple Parties– Stanford Facilities Energy
Management Team– Stanford Energy Management
& Control Systems (EMCS)– ACCO & Sunbelt Controls – kW Engineering
• Key Contents:– Equipment specifications– Hardware installation including
control hardware locations and
wiring pathways – System integration– System architecture & control
schematics– Sequence of operations
Basis of Energy Savings
VAV box w/ New DDC controls Existing Air Handling Unit (AHU)
Cooling, Heating, Damper RequestsAirflows
Supply air temp. (SAT) and duct static pressure (DSP) setpoints
Schedule & Setpoints
SAT & Status
Existing DeltaV Control System
• New DDC Thermostats with 4°F deadband• Improved scheduling with standby mode• DSP & SAT reset• Global zone setpoint control for curtailment
Energy Savings
Ensuring Persistence of Performance
• Fully programmable controllers• NiagaraAX Framework• Distech Controls• Spare I/O & controller memory
Flexibility & Future Growth
• Floor level maps color coded by temp./damper
• Zone summaries in tabular format• Intelligent alarming• Quality components
Diagnostics
• Submittal review• Detailed functional testing of 10% sample• 72 hour trend review of additional sample• 3rd party Cx Agent
Commissioning
Verified Energy Savings
y = 3.9185x + 624.05R² = 0.9699
y = 2.2642x + 536.56R² = 0.9641
0
500
1,000
1,500
2,000
2,500
0 100 200 300 400
Chill
ed W
ater
Usa
ge(t
on-h
rs/d
ay)
Cooling Degree Days (CDD)
Baseline
Post-Retrofit
Figure 3: Relationship between chilled water usage data and CDD
Verified Energy Savings
y = 41.46x + 8864.7R² = 0.9635
y = 40.001x + 1782.2R² = 0.9881
02,0004,0006,0008,000
10,00012,00014,00016,00018,00020,000
0 50 100 150 200 250
Stea
m U
sage
(lbs/
day)
Heating Degree Days (HDD)
Baseline
Post-Retrofit
Figure 4: Relationship between steam usage data and HDD
Verified Energy Savings
Annual Energy and Cost Savings Project Payback
Electricity Savings (kWh)
Chilled Water Savings (ton-hrs)
Steam Savings (lbs.)
Total Cost Savings
Measure Cost Utility
Incentive Simple
Payback (yr)
273,663 134,415 3,359,064 132,569$ 625,514$ 43,455$ 4.4
Verified (Post-Retrofit)
Efficiency Measures Still Available
50.0 55.0 60.0 65.0 70.0 75.0 80.0 85.0 90.0
12 AM 3 AM 6 AM 9 AM 12 PM 3 PM 6 PM 9 PM 12 AM
Tem
pera
ture
(F)
Time of Day
Normal Day
Cooling Setpoint Heating Setpoint Zone Setpoint
• Global temperature adjustment
• Occupancy based scheduling
Take-Aways
• Private, not-for -profit institution
• 8,500 acres• Oldest buildings from
1890s• Santa Clara County is
the main jurisdiction• >14 million square
feet, 700 buildings• ~$70 million annual
utilities spend
• Deeper savings require a comprehensive approach
• Even relatively new buildings may have out-of-date control systems that are wasting energy
• A detailed specification ensures maintenance and energy savings persist
• Consider using energy-experts with input from all parties to specify, commission and verify control systems