Retro-commissioning and on-going commissioning 23 November 2016

Transcription

1 Retro-commissioning and on-going commissioning 23 November

2 CONTENTS 1. Needs for Retro-Commissioning (RCx) 2. Retro-Commissioning (RCx) Definition and Scope 3. Briefing of RCx Process 4. Alternative Approach Energy Modeling 5. Sharing on Building Optimization Approaches 6. Key Factors for Successful Implementation of RCx in HK 7. Upcoming Trend for Retro-Commissioning 8. Conclusion 2

3 3 Section 1 Needs for Retro- Commissioning (RCx)

4 EXISTING BUILDING STOCK Buildings constructed before 1989 (>25 years old) Private office ~4.4 million m² or ~40% of total Commercial buildings ~7.1 million m² or ~65% of total Stock Distribution of Private Offices (11,060,700 m 2 at end 2014) Stock Distribution of Commercial Buildings (10,917,200 m 2 at end 2014) 4 Source: Hong Kong Property Review 2015, Rating and Valuation Department

5 EXISTING BUILDING STOCK (CONT D) 5 Source: Hong Kong Property Review 2015, Rating and Valuation Department

6 6 EXISTING BUILDING STOCK (CONT D)

7 RCx INITIATIVE UNDER ENERGY SAVING PLAN RCx is one of the key initiatives to promote energy saving for existing buildings as stated in the energy saving plan 7

8 8 Section 2 Retro- Commissioning (RCx) Definition and Scope

9 RETRO-COMMISSIONING (RCx) DEFINITION With reference to US Department of Energy, Retro-Commissioning for existing building, is a systematic investigation process for improving and optimizing the Operation & Maintenance of building equipment and systems for saving the overall energy consumption and lower energy bills. Existing Buildings cover those which were built for years or have undergone renovation. 9

10 RETRO-COMMISSIONING (RCx) DEFINITION Optimizing the system and operation efficiency by: a. Acquisition and analysis of the operational data, such as outdoor / indoor conditions, on-off schedule, sequences of operation, trend log, energy consumption record / data, etc. b. Tuning system / control induced by renovation works and/or changes in loading profiles over time, drift in control set points; c. Improving the accuracy / sensitivity of sensors or controllers; d. Optimal maintenance strategy e. Fully utilization of the design provisions (e.g. building management system, free cooling etc.) 10

11 11 Section 3 Briefing of RCx Process

12 BRIEFING OF (RCx) PROCESS Stage 1 Stage 2 Stage 3 Stage 4 Planning Investigation Implementation and Handover Post Handover 12

13 BRIEFING OF RCx PROCESS STAGE 1 Collect Building Design Information User Requirement Form Building Documentation Building Operation Values: e.g. 1) Indoor Air Temperature 2) Humidity 3) Ventilation rate 4) Building operating schedules Electricity Bills & Metering Data Carry out Initial Building Walk-through and interview with O&M staff Conduct Initial Analysis based on Existing Data (BMS/Log Sheet) Consider Performing Energy Modeling (Optional) Form Provides Building Design Information Checklist Develop a RCx Plan Form Provides User Requirement Form 13

14 BRIEFING OF RCx PROCESS STAGE 1 Coordinate and have meetings with Collect Building Design Information User Requirement Form Carry out Initial Building Walk-through and interview with O&M staff Conduct Initial Analysis based on Existing Data (BMS/Log Sheet) stakeholders Recognize on-site equipment and system condition Familiarize the plant information from O&M staff Record Visual Inspected Defects Consider Performing Energy Modeling (Optional) Develop a RCx Plan Form Provides Building Walk-Through Checklist Form Provides Photo Record for Building Walk-Through 14

15 BRIEFING OF RCx PROCESS STAGE 1 Chiller COP Performance Collect Building Design Information User Requirement Form Carry out Initial Building Walk-through and interview with O&M staff Chiller Cooling Load Profile Chiller Load Factor Chiller COP Value under Part Load Plant COP Performance Building Load over a year Conduct Initial Analysis based on Existing Data (BMS/Log Sheet) Consider Performing Energy Modeling (Optional) Develop a RCx Plan 15

16 BRIEFING OF RCx PROCESS STAGE 1 Collect Building Design Information Breakdown energy use of building accurately User Requirement Form Evaluate the amount of energy cost saving Carry out Initial Building Walk-through and interview with O&M staff Help select identified opportunities Conduct Initial Analysis based on Existing Data (BMS/Log Sheet) Consider Performing Energy Modeling (Optional) Develop a RCx Plan Form 1.5 Provides Parameter Checklist for Energy Modeling 16

17 BRIEFING OF RCx PROCESS STAGE 1 Collect Building Design Information User Requirement Form Carry out Initial Building Walk-through and interview with O&M staff Conduct Initial Analysis based on Existing Data (BMS/Log Sheet) Consider Performing Energy Modeling (Optional) Develop a RCx Plan 17

18 BRIEFING OF RCx PROCESS STAGE 2 Based on Site Measurement Plan Conduct Diagnostic Monitoring Analyze Trend Logged Data and Develop a List of Energy Gap Equipment and System Investigation Tests Use Portable data loggers Interval can be every minutes to hourly (depends on equipment) Duration of data collection: instantaneous / a week BMS Data Identify Potential Optimization Opportunities Shortlist Recommended Optimization Opportunities 18

19 BRIEFING OF RCx PROCESS STAGE 2 Plot the logged data Conduct Diagnostic Monitoring Find out the operational problems Identify possible Energy Optimization Analyze Trend Logged Data and Develop a List of Energy Gap Equipment and System Investigation Tests Opportunities (EOO) Implementation of EOO should be agreed with building owner Identify Potential Optimization Opportunities Shortlist Recommended Optimization Opportunities 19

20 BRIEFING OF RCx PROCESS STAGE 3 AND 4 Stage 3 Implementation and Handover Implement Selected Opportunities Stage 4 Post-Handover Implement Ongoing Commissioning Plan Performing Verification Ongoing Commissioning Develop RCx Final Report Develop Ongoing Commissioning Plan Conduct Training for O&M Staff 20

21 21 Section 4 Alternative Approach Energy Modeling

22 RETRO-COMMISSIONING (RCx) DEFINITION Alternative Approach Energy Modeling Objectives To generate a base model for energy utilization prediction in different condition/scenario Pre-estimate the energy saving of different Energy Optimization Opportunities (EOO) 22

23 METHODOLOGY & STANDARDS Energy Modelling Simulation Plan Information Collection On-site measurement Simulation modelling Samples of Simulated Electricity Consumption Calibration with Utility Bill 23 Predict EMO energy saving Samples of Building Information

24 METHODOLOGY & STANDARDS Energy Modelling Information Required Weather Data Building information, e.g. floor area, shape orientation Envelope configuration and construction. e.g. fenestration properties, area, type Occupancy schedule Equipment operation schedule HVAC configuration and operation Lighting, plug and miscellaneous electrical power density System setting, i.e. temperature Set Point 24 Samples of Input Parameters

25 METHODOLOGY & STANDARDS Energy Modelling Establishment of Design Model Lighting, plug and miscellaneous electrical power density Envelope Configuration and Construction 25

26 METHODOLOGY & STANDARDS Energy Modelling Establishment of Design Model 26 Occupancy schedule and Equipment schedule HVAC configuration and operation

27 METHODOLOGY & STANDARDS Energy Modelling Calibration on Design Model to Suit for Real Case Envelope configuration and construction. e.g. fenestration properties, area, type Occupancy schedule Equipment operation schedule HVAC configuration and operation Lighting, plug and miscellaneous electrical power density Electricity consumption (KWh) 600, , , , , ,000 Electricity Consumption (Calibrated Model) 0 Sample of Simulated Electricity Consumption (Calibrated) Heat Rejection Pumps & Aux Area Lighting Misc Equipment Ventilation Fans Space Cooling System setting, i.e. temperature Set Point 27 Samples of Input Parameters for Calibration

28 EXAMPLE OF SIMULATION RESULT Breakdown of Total Energy Consumption for the building Cooling tower Chiller Chiller 28

29 METHODOLOGY & STANDARDS Energy Modelling Review on the Energy Distribution on Individual BS Systems Envelope configuration and construction. HVAC Systems Occupancy schedule Electrical Systems Equipment operation schedule HVAC configuration and operation Lighting, plug and miscellaneous electrical power density Energy Modelling Lighting Systems Plumbing Systems System setting, i.e. temperature Set Point Miscellaneous Systems Calibrated Parameters Energy Distribution 29

30 EXAMPLE OF SIMULATION RESULT Result Generate From Model Electricity Consumption of different HVAC System Sample diagram of the energy consumption for chiller Sample diagram of the energy consumption for Ventilation fans Sample diagram of the energy consumption for Cooling Tower equipment Sample diagram of the energy consumption for AC pumps 30

31 EXAMPLE OF SIMULATION RESULT Result Generate From Model Sample diagram of Monthly Peak Cooling Load Sample diagram of Yearly Percentage of Occurrence Time Energy Saving with different EMOs Sample diagram of energy cost saving estimation (kwh) Baseline EOO 1 EOO 2 EOO 3 Total Baseline energy consumption Increase heat exchanger Increase set point temp. Improve chiller operation Total Energy Saving by approach temp. from 22.5deg.C to sequencing incorporating all EMOs 24deg.C Sample diagram of energy saving comparison between EMOs 31

32 32 Section 5 Sharing on Building Optimization Approaches

33 33 Section 5a Site Measurement Methodology

34 SITE MEASUREMENT METHODOLOGY Chilled / Condenser Water Temperature Sensor Verification Method 1 Method 2 Measuring through binder style test point Method 3 Measuring through thermowell Measuring through pipe well or pipework drain point 34

35 SITE MEASUREMENT METHODOLOGY Chilled / Condenser Water Flow Rate Verification Method 1 Method 2 Measuring flow rate through double regulating valve Method 3 Measuring differential pressure to estimate Water flow rate Measuring flow rate with ultrasonic flow meter 35

36 36 Section 5b Some Hints On Optimization Approaches

37 SOME HINTS ON OPTIMIZATION APPROACHES Hints Optimization Approaches 1 Inaccuracy of sensor Verification of the actual chiller plant performance for further investigation 2 Improper distribution of chiller load factor 3 Low Chilled Water Supply Temperature (CHWST) 4 High approach temperature in heat exchanger Optimize chiller COP by chiller sequencing Increase the chiller efficiency by increasing the CHWST Minimize the approach temp difference at the heat exchanger for better chiller COP 5 Low indoor air temperature in some local area Optimize room temperature settings to minimize cooling load energy consumption 6 High lux level in some local area Optimize lighting level to minimize the light energy consumption 37

38 SOME HINTS ON OPTIMIZATION APPROACHES (1) Hints Inaccuracy of Sensors Inaccuracy of CHWS and CHWR Sensor Result in inaccurate value on COP based on data log sheet Annual Plant COP: 3.9 (Based on Log Sheet) Annual Plant COP: 3.7 (Based on Measured Result) 38

39 SOME HINTS ON OPTIMIZATION APPROACHES (1) Analysis Verification of Chiller Plant COP Even Worse COP: 3.9 (Log Sheet) COP: 3.7 (Measured Result) 39

40 SOME HINTS ON OPTIMIZATION APPROACHES (1) Analysis Verification of Cooling Load Profile Installed Capacity : kw (3000RT) Peak Loading : 8113 kw (~2300RT) 40

41 SOME HINTS ON OPTIMIZATION APPROACHES (2) Hints Load Factor (Chilled Water Circuit) - High Load Factor for VSD Chiller - Low Load Factor for CSD Chiller 41 41

42 SOME HINTS ON OPTIMIZATION APPROACHES (2) Hints Load Factor (Chilled Water Circuit) CSD Chiller 1: 55 65% CSD Chiller 3: 55 65% VSD Chiller 2: 85 95% CSD Chiller 4: 55 65% 42

43 SOME HINTS ON OPTIMIZATION APPROACHES (2) Optimization Approaches Chiller Sequencing Lower Load Factor (50-70%) for VSD Chiller for better Chiller COP Increase Load Factor (80-90%) for CSD Chiller 43

44 SOME HINTS ON OPTIMIZATION APPROACHES (2) Optimization Approaches Chiller Sequencing Higher COP Proposed Condition Existing Condition

45 SOME HINTS ON OPTIMIZATION APPROACHES (3) Hints Low Chilled Water Supply Temperature (Chilled Water Circuit) Low load condition occurs in Jan Mar Cooling load is only 50% of the full capacity Chilled Water Supply Temperature is in 6.5 deg C (Chiller 1) / 7.5 deg C (Chiller 2) 45

46 SOME HINTS ON OPTIMIZATION APPROACHES (3) Optimization Approaches Chilled Water Supply Temperature Reset (Chilled Water Circuit) With reference to US Department of Energy, System efficiency increases by 3% - 5% when supply temperature is raised by 1 deg C 46

47 SOME HINTS ON OPTIMIZATION APPROACHES (4) Hints - Heat Exchanger (Heat Rejection System) Check Approach temperature at HX IN OUT Approach Temperature reached to 5-6 deg C It lasts for May September 47

48 SOME HINTS ON OPTIMIZATION APPROACHES (4) Optimization Approaches Heat Exchanger (Heat Rejection System) - Perform Overhaul Maintenance Work Existing Condition : Once a year, March Proposed Condition : Every 3 months - Perform Backwash Maintenance Work Existing Condition : 6 times a year Proposed Condition : 12 times a year - Add more plate if efficiency drops Objective: Minimize the Approach Temperature at HX 48

49 SOME HINTS ON OPTIMIZATION APPROACHES (4) Energy Savings Reducing the Approach Temperature and lower the Entering Condenser Water Temperature (Heat Rejection System) With reference to US Department of Energy and O&M Best Practices (Sullivan et al. 2004), System efficiency can be increased by 2% - 3% if condenser water temperature is lowered by 2 deg C 49

50 SOME HINTS ON OPTIMIZATION APPROACHES (5) Hints - Thermal Analysis (Air Side System) - Data loggers are placed to 9 points (wall side, center of the office) - Wall side temperature reaches 22.5 deg C 24 deg C - Average Temperature: 23 deg C Avg. Temp: 23 deg C 50

51 SOME HINTS ON OPTIMIZATION APPROACHES (5) Hints - Thermal Analysis (Air Side System) Findings: Relatively Low Thermostat Setting: 15 deg C 51

52 SOME HINTS ON OPTIMIZATION APPROACHES (5) Optimization Approaches Indoor Temperature Reset (Air Side System) Proposed Avg. Temp: 25deg C 52

53 SOME HINTS ON OPTIMIZATION APPROACHES (6) Hints - Lux Level Analysis (Lighting System) - 29 points are tested for the lux level - Covers conference room, library, office and corridors Optimization Approaches Lux Level Analysis(Lighting System) Lux Level: High Side in Corridor Optimization Approach : reduce luminaries number 53

54 54 Section 6 Key Factors for Successful Implementation of RCx in HK

55 KEY FACTORS FOR SUCCESSFUL IMPLEMENTATION OF RCx IN HK: 1. Recognition by Building owners, Facility Management Staff, etc. on RCx s value 2. Technical guidance e.g. models and tools and proforma specification 3. Service providers and experienced practitioners for RCx implementation 4. Training for RCx 55

56 56 Section 7 Upcoming Trend for Retro-Commissioning

57 UPCOMING TREND FOR RETRO-COMMISSIONING Before Connected Time and Cost are High TIME TO RESOLUTION: hours COST: $$$$$ DISRUPTION TO FACILITY: High 58

58 60 UPCOMING TREND FOR RETRO-COMMISSIONING

59 UPCOMING TREND FOR RETRO-COMMISSIONING Big Data relates to data creation, storage, retrieval and analysis that is remarkable in terms of volume, velocity, and variety. Integration Cloud Computing Building Services Systems 61

60 UPCOMING TREND FOR RETRO-COMMISSIONING Smart Centre Area Zone 1 Area Zone 2 Area Zone 3 Area Zone 4 Area Zone 5 Area Zone 6 Smart Centre 1 Smart Centre 2 Smart Centre centralized energy management through real-time monitoring 64

61 70 Section 8 Conclusion

62 CONCLUSION Past Over 90% buildings age more than 10 years Most of buildings lost 30% efficiency in the first few years Present RCx systematic process to periodically check building performance Energy Saving Scheme Future Smart Centre for central monitoring Automatic System Health Checking Easy access Various report types are provided System self adjustment and optimization 71

63 72