Case Study of Two MBCx Projects:Using M&V to Track Energy Performance

David Jump, Ph.D., P.E.Quantum Energy Services & Technologies, Inc.

ICEBO, November 1, 2007

2

Overview

This presentation will discuss:Role of M&V in RCxApplication in two UC Berkeley BuildingsResultsDiscussion & Conclusion

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Situation• RCx is a means to improve a building’s energy efficiency

OwnersEE Programs

• “RCx Measures”Correct and optimize system operations

• Operational changes• Control system changes

Justification provided by measure cost-effectiveness

• RCx measure recommendations based on savings estimates

4

Situation• RCx measure savings estimates are based on:

Design documentationEquipment specificationsMonitored operational data

• Independent data loggers• Control system trends

Bin models, engineering models, computer simulations, etc.

• Do savings estimates = “real” savings?Model errorsIncomplete or inaccurate dataIncorrect assumptionsEtc.

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SituationRisks to Owner:

Savings not delivered, no return on investmentNo ability to track actual savingsSavings do not last:

• “Soft” measures that can be and often are defeatedEE Program Risks:

Program’s claimed savings do not stand up to third party reviewSavings lifetimes are shortNegative impact on program realization rates

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Need for Robust M&V in RCx ProjectsNeeds:• Demonstrate actual, verified energy savings benefits of RCx• Provide a mechanism to determine measure savings

persistence

Opportunities:• Standardization of M&V processes for RCx

California Commissioning Collaborative Project• Provide information tools for operators and owners to

maintain savings• Basis for further energy performance improvements

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Basic M&V

International Performance Measurement and Verification Protocol (IPMVP) Chapter 3 says:

Energy Savings = Baseyear Energy Use – Post-Retrofit Energy Use ± Adjustments

• Baseline energy use is modeled• Model generates what baseline use would have been

under post-install conditions • ‘Adjusted baseline’ is compared with measured use to

generate savings

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0

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Jan-0

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0kW

kWactual kWbaseline

Baseline Period

Post-Installation Period

Quantifying Savings

Verified savings are based on energy measurements before and after improvements

Savings estimates are based on data collected in baseline period

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IPMVP M&V OptionsRetrofit Isolation Options:• Option A: Allows stipulation of some parameters• Option B: Retrofit isolation – continuous monitoring of parameters

Focus is on systems and equipment – similar to RCx.

Whole Building Options:• Option C: Utility bill analysis• Option D: Calibrated computer simulation

Sometimes used with isolated systems, as applicable• Used when savings distinguishable from variation in use (typ. >15%)

• Option B selected for UC Berkeley Magnifies savings as a proportion of use+ addresses savings persistence, provides tracking toolsTechnique also applied at whole-building level

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UC Berkeley MBCx Project

• UC Berkeley has significant monitoring resources to devote to this project

Web-based utility information system• Whole building kW and steam meters• Electric and steam trended at 15 minute intervals• Data stored indefinitely

Web-based points mapped from BAS• Chiller kW• BAS points trended at 1 minute intervals• Data stored for 6 months

11

Soda Hall• UC Berkeley’s Computer Science Department (24/7 operation)• 109,000 ft2

• Energy Use Intensity: 174 kBtu/ft2-yr • 2 - 215 ton chillers (lead/lag)• Constant Speed Primary/Variable Speed Secondary Chilled Water

System• Two 2-speed, forced draft, open loop cooling towers• 3 Main VAV AHUs,

AHU1 serves building core, AHUs 3 and 4 serve the perimeter, with hot water reheat

• 11 computer room DX units, water cooled with variable speed pumps• Steam to hot water heat exchanger, 2 variable speed HW pumps

12

Soda Hall RCx Findings• Minimum VAV Box Damper Positions at 50%

Causes excessive reheat in perimeter zonesLittle modulation of fan VFD

• Several AHU VFDs broken or not modulatingReturn to designed VAV operationReturn to scheduled operation

• Re-establish supply air temperature set point reset control in AHU1

• Other measures

• Approximately 483,000 kWh (10%), 2.7M lbs/yr steam (51%)Estimated using DOE2 analysis

• Cost reduction $84,000 (14%), Payback 0.7 years

13

Soda Hall Affected SystemsSystem Equipment Affected

by ECM?Available Points

XMain Electric Meters (2) kWMain Steam Meters (2) lb

XChillers 1 and 2 kWPrimary Chilled Water Pumps P-5, P-6 StatusSecondary Chilled Water Pumps, P-3, P-4 VFD speed

XCooling Towers High/Low StatusCondenser Water Pumps P-7, P-8 Status

XAHU-1, SF-11, EF-12, EF-13 VFD speedAHU-2, SF-14, EF-15 StatusAHU-3, SF-16, SF-17 VFD speedAHU-4, SF-18, SF-19 VFD speedAHU-5, SF-20 Status

Chiller Room 181, SF-2, EF-2 StatusChiller Room 179, SF-3A, SF-3B, EF-1A, EF-1B Status

AC UnitsCondenser Water Pumps P-9, P-10 VFD speedAC-31 through AC-41 Status

XHot Water Pumps P-1, P-2 VFD Speed

Hot Water System

Whole Building

Condenser Water System

Chilled Water System

Air Distribution System

Chiller Room Fans

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Define the Baseline Period & Collect Data

• 8 months of trended data collected• Baseline period selected to cover widest range of operating

conditions ~ 3 months.

• Energy use for each system to be totaled each dayBasis for analysis and reporting

• “Proxy” Variables on EMCS:Constant load equipment: measure operating kW

• Equipment status becomes proxy for kW Variable load equipment: log kW and VFD speed

• VFD speed signal becomes proxy for kW

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“Proxy” Variable: VFD speed for kW

0

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0 20 40 60 80 100 120

AHU-1 Fan Speed %

AH

U-1

Fan

kW

Actual Cubic polynomial

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M&V “Diagnostics”Soda Hall

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1,000

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061/3

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Date

kWh

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Deg

F

AHU 1 Daily kWh AHU 3 Daily kWh AHU 4 Daily kWh OAT Daily Average

AHU 1 supply fan malf. begins here. Same date as economizer fix.

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M&V DiagnosticsSoda Hall

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1,000

4/1/20

064/3

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065/9

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5/11/2

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/2006

Date

kWh

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Deg

F

AHU 1 Daily kWh AHU 3 Daily kWh AHU 4 Daily kWh OAT Daily Average

VAV box implementation begins

VAV box implementation complete

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Baseline Model: Soda Hall• Total Building Electric Building Steam

• Peak Period Electric HVAC System Electric

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Soda Hall M&V: HVAC Systems

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/28/20

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Date

Dai

ly k

Wh

Use

HVAC Daily kWh Usage Baseline Post-Install Model

Date Break

Baseline Model:kWh = 79.9*OAT + 1129RMSE = 136 kWh

Baseline Period Post-Installation Period

Post-Install Model:kWh = 44.1*OAT - 336RMSE = 213 kWh

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Soda Hall: Estimated vs. Verified Savings

Whole Building HVAC SystemkWh 483,008 216,716 462,472kW - 22 50Lbs. Steam 2,713,650 854,407* based on eQUEST model** based on baseline and post-installation measurements and TMY OAT data

Verified Savings**Source Estimated

Savings*

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Tan Hall• UC Berkeley’s Chemistry and Chemical Engineering

Departments• 7 above-grade, 2 below-grade levels• 106,000 ft2

• 100% outside air through 4 VFD-controlled 100 HP supply fans

• Steam heating and CHW cooling coils in AHU• Separate exhaust system on roof: 4 VFD-controlled 60 HP

exhaust fans• 1 475-ton chiller, constant speed primary loop• Constant speed CW loop – Tower shared among buildings• Steam-to HW HX system, circulated to perimeter zone boxes

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Tan Hall RCx Findings

• Chilled water and condenser water pumps operating in parallel instead of lead/lag

Balancing vales on each were closed downShut off one pump, rebalance flow and operate in lead/lag mode as intended

• Chiller outside air lockout temperature sequence not functioningOAT set point also too highCorrect operation and lower set point 2 °F

• Leaky steam valve in AHU – caused simultaneous heating and cooling

• Savings: 654,000 kWh (14%), 90 kW, 10.5 M lbs steam (62%)Estimated using bin analysis

• Cost reduction $154,000 (19%), Payback 0.02 years

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Tan Hall Affected SystemsSystem Equipment Affected by

ECM?Available

PointsX

Main 480/277 Electric Meter kWMain 220/110 Electric Meter kWMain Steam Meter lbs/hr

XChiller (VS) kWPrimary Chilled Water Pumps CHWP-1, CHWP-2 (CS) Status

XCondenser Water Pumps CDWP-1, CDWP-2 (CS) StatusCooling Tower (CS, 2-speed) Not Avail.

AHU-3 XAHU-3 Supply Fans SF-1, SF-2, SF-3, SF-4 (CS) S/S & SpeedAHU-3 Exhaust Fans EF-1, EF-2, EF-3, EF-4 (CS) S/S & SpeedTerminal Boxes and Fume Hoods associated with AHU-3 NA

AHU-1AHU-1 Chemical Storage AH-1, SE-1 Status

AHU-2AHU-2 Chemical Storage AH-2, SE-2 Status

XHeat Exchanger HWC-1Hot Water Pumps HHWP-1, HHWP-2 Status

Lighting Circuits NAPlug Loads

Plug Load Circuits NA

Domestic Water Pumps NA

Whole Building

Chilled Water System

Condenser Water System

Heating Water System

Lighting System

Domestic Water

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Tan Hall Diagnostics

0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

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061/3

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1/5/20

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/2006

1/9/20

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Date

Dai

ly k

Wh

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10

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Deg

. F

AHU-3 Supply Fans Avg. Daily Temp.

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Tan Hall Diagnostics – cont.

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/2006

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065/5

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5/7/20

065/9

/2006

5/11/2

006

5/13/2

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5/15/2

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5/17/2

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5/19/2

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/2006

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/2006

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Date

Dai

ly k

Wh

0

10

20

30

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50

60

70

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Deg

. F

AHU-3 Supply Fans Avg. Daily Temp.

Measures Implemented

SF-1 Fails. The other fans ramp up to meet setpoint.

SF-1 repaired. Fans return to normal operation.

Prefilters and bags changed.

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M&V Models: Tan Hall

Whole Building Electric Whole Building Steam

Peak Period Electric Chilled Water System Electric

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Tan Hall M&V: Whole-Building Electric

0

5,000

10,000

15,000

20,000

25,000

6/1/2006 6/3/2006 6/5/2006 6/7/2006 6/9/2006 6/11/2006 6/13/2006 6/15/2006 6/17/2006 6/19/2006 6/21/2006 6/23/2006 6/25/2006

Date

Dai

ly k

Wh

0

10

20

30

40

50

60

70

80

Deg

. F

Total Building Daily kWh Average Daily Outside Air Temperature Baseline New Baseline

Baseline ModelR2 = 0.75RMSE = 581 kWh

New BaselineR2 = 0.88RMSE = 438 kWh

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Tan Hall M&V: Whole-Building Steam

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

90,000

6/1/2006 6/3/2006 6/5/2006 6/7/2006 6/9/2006 6/11/2006 6/13/2006 6/15/2006 6/17/2006 6/19/2006 6/21/2006 6/23/2006 6/25/2006

Date

Dai

ly S

team

lbs

0

10

20

30

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50

60

70

80

Deg

. F

Steam Baseline New Baseline Average Daily Outside Air Temperature

New Baseline

Baseline Model

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Tan Hall M&V: Chilled Water System

0

1,000

2,000

3,000

4,000

5,000

6,000

6/1/2006 6/3/2006 6/5/2006 6/7/2006 6/9/2006 6/11/2006 6/13/2006 6/15/2006 6/17/2006 6/19/2006 6/21/2006 6/23/2006 6/25/2006

Date

Dai

ly k

Wh

0

10

20

30

40

50

60

70

80

Deg

. F

Chilled Water System Average Daily Outside Air Temperature Baseline New Baseline

New BaselineR2 = 0.95RMSE = 251 kWh

Baseline ModelR2 = 0.87RMSE = 486 kWh

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Tan Hall: Estimated vs. Verified Savings

Whole Building CHW SystemkWh 653,575 663,184 686,519kW 91 69Lbs. Steam 10,543,991 5,995,232* based on engineering calculations** based on baseline and post-installation measurements and TMY OAT data

Verified Savings**Source Estimated

Savings*

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Costs

Soda Hall 4,442$ 62,160$ 51,087$ 117,689$ Tan Hall 22,573$ 53,000$ 15,300$ 90,873$

Building Metering Costs

MBCx Agent Costs

In-House Costs Total

• Including all costs, project remains cost-effective:Soda Hall: 1.7 year paybackTan Hall: 0.7 year payback

• Added costs of metering hardware and software did not overburden project’s costs

• In private sector – metering costs lowerExisting electric metersSophisticated BAS systemsMBCx approach should be viable

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Discussion

• Consider new approach:Focus project resources on verified savings instead of estimated savings approach

• More rigorous savings analysis, more reliable results

• Install all low-cost measures • Estimate savings for only higher cost measures• Leave in place capability to track & tally savings• Diagnostic benefits of approach• Addresses savings persistence

• BarrierLack of understanding of M&VM&V training required

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Conclusion• Soda & Tan Hall projects showed technique to integrate M&V

into RCx• Technique as tools:

Diagnostic capability, Verify savings, track energy use

• Other benefitsPersistence of RCx savingsLess uncertainty in savings Establish new baselines for next project

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Related WorkM&V Guidelines:• Energy Valuation Organization’s International Performance

Measurement and Verification Protocol (IPMVP)New 2007 release available now at: www.evo-world.org

• ASHRAE Guideline 14: www.ashrae.org

• California Commissioning Collaborative: Verification of Savings Project

Review current M&V methods within RCx projectsRecommend best practices for M&V in RCxDisseminate results