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1 Commissioning of Existing Buildings: A Triple Play on Energy, Comfort, and Operability David E. Claridge Energy Systems Laboratory Texas A&M University.

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Presentation on theme: "1 Commissioning of Existing Buildings: A Triple Play on Energy, Comfort, and Operability David E. Claridge Energy Systems Laboratory Texas A&M University."— Presentation transcript:

1 1 Commissioning of Existing Buildings: A Triple Play on Energy, Comfort, and Operability David E. Claridge Energy Systems Laboratory Texas A&M University System

2 2 Outline  Personal History of Retro-Cx  1980s  LoanSTAR Program  ESL Retro-Cx Methodology  Applications and Benefits of Retro-Cx

3 3 Personal History of Retro-Cx: 1980s Recreation Center Study  150,000 ft 2  Indoor ice rink  Indoor swimming and diving pools  Multi-purpose gymnasium  Exercise rooms  Locker rooms

4 4 Rec Center: Audit + Retrofits  Operational Measures  Reschedule cleaning crew  Delamp overlit areas  Recalibrate natural gas meter  Don’t use tennis court lights as security lights  Retrofits  Insulation jacket on ice rink chiller  Install heat reclaim on ice rink compressors (DHW)  Re-insulate ceiling of women’s locker room  Install pool cover (not done)  Result: 30% energy savings

5 5 Rec Center: Knowledge Base for Expert System  Opportunities from analysis of daily energy use  Modify snow melt on outdoor loading ramp  Reduce gutter heat tape usage  Correct cross-wiring problem in men’s locker room  Correct brine circulation problem  Reactivate ice rink heat reclaim for showers  Adjust temperature on heat reclaim  Raise ice rink brine temperature  Use cold water for ice resurfacing  Disconnect steam patch from adjacent building  Change incorrect gas meter reading procedure  ~25% savings

6 6 Personal History of Retro-Cx 1989 LoanSTAR Metering  Determine savings from retrofits  Identify opportunities for additional savings  Improve retrofit selection  Provide energy use database

7 7 Personal History of Retro-Cx ESL Continuous Commissioning ®  Started in 1993 with improved O&M practices  Initial buildings were from the Texas LoanSTAR program, i.e., had undergone major capital retrofits  Buildings all had hourly or 15-minute metered electrical and thermal data  Building modeling showed additional savings were possible with optimized systems  Site visits to buildings verified additional savings were possible if energy systems were optimized

8 8 Early Commissioning Results from LoanSTAR Projects $0 $500,000 $1,000,000 $1,500,000 $2,000,000 $2,500,000 $3,000,000 $3,500,000 $4,000,000 $4,500,000 $5,000,000 TSHUTMBUTHSC Before RetrofitAfter RetrofitAfter CC

9 9 Energy, Comfort and Operability from Retro-Cx of Starr Building  99,000 ft 2 office building w/3&6-story wings  Four MZ AHUs  Two 175-ton chillers  Two 2.4 MMBtu/hr gas fired boilers  EMCS  MAJOR COMFORT PROBLEMS

10 10 Building Problem History IAQ Problem in 1982  Two AHUs sucked in garage air through exhaust grills  Blocked exhaust air dampers to prevent garage air back-flow

11 11 Building Problem History Security Problems in 1990  Closers would not close doors

12 12 Building Problem History Solution to Security Problems  Cut a 4 foot by 4 foot hole on the exterior wall to relieve the building positive pressure

13 13 Building Problem History Thermal Comfort Problems  High room temperature (80ºF) and high RH (70%) during summer  Low room temperature during winter in some rooms  Extremely high utility bills  Considered selling building

14 14 Measurements and analysis found AHUAFBCTotal Total CFM Measured73,20012,80026,90027,800140,700 Designed36,80010,00044, ,225 O.A. CFM 43,500 6,50012,80017,900 79,950 Area30,300 6,80040,80021,10099,000  +0.1 inH2O pressurization  Airflow 25% above design-value  Measured OA flow 8 times required flow

15 15 Found Optimum Total Flows Below Design Values as Shown  Total air flow reduced by 38% to 78% of design value  Outside air flow reduced by 87% AHUABCFTotal Total CFM As-found Recommended Recommended/Design 73,200 25, ,940 37, ,700 17, ,800 5, ,700 87, O.A. CFMAs-found Recommended 43,500 3,000 12,750 4,000 10,320 2,000 6, ,000 9,600

16 16 Simulated Performance with Airflow Correction and Optimum Cold- and Hot-deck Reset Schedules Before CC ® After CC ® Savings Savings % Chiller Electricity (kWH/yr) 1,638,0001,157,000481,00029 Hot Water (MCF/yr) 4, ,21686

17 17 Comfort Improvement Following Retro-Cx  Office workers interviewed the next summer all noted significant comfort improvement  Measurements in 18 rooms showed: ConditionsBefore R-CxAfter R-Cx Room CO 2 Level ppm ppm Room Temperature °F °F Room Relative Humidity58% - 69%50% - 55% Building Positive Pressure 0.1 in H 2 O0.02 in H 2 O

18 18 Measured Gas Consumption Before and After R-Cx

19 19 Case-Study Conclusions  Retro-Cx restored this building to comfortable operation without adding heating or cooling capacity  Retro-Cx reduced chiller consumption by 29% and gas consumption by 67%  Building site EUI reduced 33% from 151 kBtu/ft 2 -yr to 101 kBtu/ft 2 -yr

20 20 Retro-Cx (CC ® version) Definition  CC ® is an ongoing process to:  Resolve operating problems  Improve comfort  Optimize energy use, and  Identify retrofits for existing commercial and institutional buildings and central plant facilities. It specifically optimizes performance for the way the building is currently being used.

21 21 CC ® Process Outline  CC ® Assessment  Develop Performance Baselines  Examine/Measure Facility Systems  Implement CC ® Measures  Document Changes  Keep Commissioning Continuous

22 22 1. Stand-alone Process - older buildings 2.“New” buildings 3.After Retrofits 4.Separate Measure in Retrofit Program Applications of Retro-Cx

23 23 Stand-alone Process Kleberg Building

24 24 Kleberg: Major R-Cx Measures Implemented 1. Applied preheat & cold deck reset schedules 2. Utilized economizer cycle 3. Optimized CHW pump control 4. Performed lab air balance âReduced building pressure from.05 inWG to.03 inWG âReduced fume hood exhaust pressure from 3 inWG to 0.75 inWG

25 25 Kleberg Building  Cooling Savings 64%  Heating Savings 84%  Comfort  Temp control ++  Humidity reduced

26 26 Retro-Cx at A&M  Started in 1996  Cumulative Savings: $50 million plus  Cumulative Cost: $7 million

27 27 Retro-Cx Application: “New” Buildings Matheson Courthouse – Salt Lake City

28 28 Key Facts  Conditioned Area: 370,000 ft 2  37 courtrooms, offices, holding cells, 3 level underground  Built 1997  2001: $1.08/ft 2 energy cost  Significant comfort problems

29 29 Key Retro-Cx Measures Implemented  Sensor calibration  Optimize boiler & chiller sequencing  Optimize start/stop  Correct damper and valve problems  Optimize cold-deck reset, duct static reset, HW supply temp, terminal box minimum flow

30 30 Matheson Courthouse Results 1.Energy Cost reduced to $0.77/ft 2 /yr from $1.08/ft 2 /yr for 1.2 yr payback 2.Facility manager complimented by occupants on T/RH improvements 3.Morning warm-up/cool-down works properly 4.Improved building pressurization and eliminated exhaust odor from underground parking

31 31 Matheson Courthouse

32 32 Retro-Cx Application after Retrofits LoanSTAR Projects $0 $500,000 $1,000,000 $1,500,000 $2,000,000 $2,500,000 $3,000,000 $3,500,000 $4,000,000 $4,500,000 $5,000,000 TSHUTMBUTHSC Before RetrofitAfter RetrofitAfter CC

33 33 Retro-Cx as ECM in a Retrofit Project  Alamo Community College District (San Antonio)  5 campuses  69 buildings  2.35 million ft 2

34 34 Project Summary  District wide retrofits - Lighting & motion sensors - HVAC replacements units - Central plant improvements - Energy management controls upgrades - New cooling tower [SPC]  Retro-Cx $3.5 M Project 6.7 yr simple payback

35 35 41-month Savings = $1,307,400 Retro-Cx ~2/3 of savings

36 36 Walter Reed Army Institute of Research (WRAIR)

37 37 Retro-Cx Measures at WRAIR  Optimize operation of  Air to air heat exchangers  AHUs  Terminal boxes  Chilled water system  Heating water system

38 38 Cumulative Energy Savings  Electricity savings 13.6% $552,000/yr  Gas savings 27.5% $246,000/yr  Payback < 1 yr

39 39 Comfort/Operational Improvements  Commanding General thanked facility staff for obvious improvements  Temperature and RH improvements in numerous offices  High pitched noise eliminated

40 40 ENERGY TRACKING ESSENTIAL Kleberg Heating/Cooling Savings Energy Type Pre-Cx Baseline (MMBtu/y) Post-Cx Savings (%) Year 2000 Savings (%) Chilled Water 72, %37.7% Heating Water 43, %62.2%

41 41 Kleberg CHW before/after follow-up

42 42 Retro-Cx Is a Triple Play!  Energy Savings Pay the Bill (0-3 yrs)  Improves Comfort!  Improves Operability!


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