Existing Building Energy Saving Ir Cary Chan Executive Director, - PowerPoint PPT Presentation

Existing Building Energy Saving Ir Cary Chan Executive Director, HK Green Building Council

Aviation industry 1981 1971 1969 1930s 1903 2

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A big gap to fill 7

Convincing responses to your boss ! Deliver !

Implementation of energy management E nergy Management Process POLICY ACT OBJECTIVE & TARGET AUDIT DATABASE PLAN Knowledge-based ANALYSIS ACTION PLAN IMPLEMENTATION DO DIAGNOSIS (Retro-Cx) MEASUREMENT & VERIFICATION CHE CK REVIEW MEETING & REPORT BENCHMARKING

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Design parameters Load calculation System design Equipment selection T esting and commissioning

Idea of ACT -Shop • Groups of representatives from buildings going through a retro-commissioning process • Buildings as living laboratories • HKGBC as facilitator Learning from peers • • Building up knowledge Together

In participating in the ACT -Shop programme : • Actively supporting HK gov’s energy saving plan • Building up the competence for the industry on retro- commissioning through • developing the data/knowledge base • developing a systematic approach for retro-commissioning • demonstrating the value of retro-commissioning • transferring the knowledge and skills to the industry • establishing a practical operation & management system • Promoting the adoption of best practices to the industry

Initial findings

Different types of building, system design , age.. Bldg A Bldg B Bldg C Bldg D Bldg E Office Composite (Podium+ Composite (Office Type Composite Hotel (Industrial Building T owers) +Education) Renovation) Age (Yrs) 25 41 24 20 20 IFA (sqm) ~20,000 ~36,000 ~150,000 ~4,500 ~45,000 7x1000TR ． 4x320TR 4x180TR Water-cooled 1x150TR Air-cooled Water-cooled 4x400TR Chiller Water-Cooled 4x190TR Air-cooled 1x150TR Air-cooled 2x400TR Air-cooled (new) (new) (new) Water-cooled(Night) Cooling 4 4 6+2 N/A N/A T ower Differential Differential Differential Differential Differential Pressure Control Pressure Bypass Pressure Bypass Pressure Bypass Pressure Bypass Bypass Water-cooled: 4 7+2 Pumps 4+1 2+1 4+1 Air-cooled: 4+1 4+2 (Office T ower) Variable Speed 140TR Heat Pump Heat Exchanger natural ventilation Fresh air treated by Features Chiller for hot water for high rise office tower allowed FCU

Availability of data and information varies !

Approach a and Met etho hod Has to consider : • Practicality • Minimum provision of instrument • Availability of data and information

“ACT -Shop” – Data Analysis Method 1. Re-tune (retro-Cx) 1.1 Valve authority 1.2 Set-point 1.3 Equipment operation Re-tune: Performance line evaluation 1.1 2. Valve Authority Discharge valve • Peak demand shedding Double regulating 3. • 4. Set-point reset valve, etc. 6 2 Control Set-point Cooling load Loading 1.2 Re-tune: 4. DP WS 1. DT CHWS Outdoor Ambient Temperature Outdoor Ambient Temperature 5. T APP 2. DT A ,C 3 6. T APP 3. DSP Peak Demand ,C T summer 1.3 100% %load winter 0:00 24:00 Cooling Load 19

““ACT -Shop” – Data Analysis Method (retro-Cx) Bldg A Bldg B Bldg C Bldg D Bldg E Low DTCHW summer 5.0 ° C 5.0 ° C 5.0 ° C 2.5 ° C 3.4 ° C DTCH 2.5 ° C 3.2 ° C 3.0 ° C 0.75 ° C 2.0 ° C DTCHW winter W TCHWS TCHWS summer 7.8 ° C 7 ° C 8 ° C 9.5 ° C 8.5 ° C reset at 10 ° C 11 ° C 9.5 ° C 14 ° C 10 ° C TCHWS winter winter COP,CH summer 6.3 3.3 5.3 3.2 1.6 Low COP,Ch winter 13 3.4 4.2 2.9 2.5 CO P 60 115 88 33 48.3 EUI(Chiller) kWh/m 2 /year kWh/m 2 /year kWh/m 2 /year kWh/m 2 /year kWh/m 2 /year 20

1. Re-tune – Chiller Operation Percentage of Full Load Ampere (%FLA) More 100% Full Load FLA 3 2 Chillers 1 Chiller Chillers Extra Zone Zone Zone chiller Less FLA Cooling Load/m 2 • Good operation • Poor operation (high % full load ampere due to deterioration of chiller capacity) 21

1. Re-tune – Chiller operation (cont’d) % Full Load Ampere issue Bldg C Bldg E 100% 100% Percentage of Full Load Amp Percentage of Full Load Amp 80% 80% 60% 60% Chiller Extra chiller operate at 40% 40% in operation high % FLA 20% 20% 0% 0% 0 20 40 60 80 100 120 0 20 40 60 80 100 120 Cooling Load Intensity Cooling Load Intensity 1 Chiller 2 Chiller 3 Chiller 4 Chiller 5 Chiller 1 Chiller 2 Chiller 3 Chiller 4 Chiller 22

1. Re-tune – Chiller Operation (cont’d) Delta T of Chilled Water issue Large Delta T of Chilled Water Design Value Delta -T Delta T of Chilled Water 3 2 Chillers Chillers Zone 1 Chiller Zone Zone Small Delta-T Cooling Load/m 2 • Good operation • Poor operation (narrow delta T due to excessive flow through chillers or bypass pipe) 23

1. Re-tune – Chiller Operation (cont’d) Delta T of Chilled Water issue Bldg C Bldg B 6.0 6.0 Delta T of Chilled Water (°C) Delta T of Chilled Water (°C) 5.0 5.0 4.0 4.0 One chiller capacity 3.0 3.0 but two pumps Extra flow through 2.0 2.0 bypass pipe 1.0 1.0 0.0 0.0 0 20 40 60 80 100 0 20 40 60 80 100 120 Cooling Load Intensity Cooling Load Intensity 1 Chiller 2 Chiller 3 Chiller 4 Chiller 5 Chiller 1 WCC 0.5ACC + 0.5WCC Bldg E 6.0 Delta T of Chilled Water (°C) 5.0 4.0 3.0 Extra flow through chiller 2.0 1.0 0.0 0 20 40 60 80 100 120 Cooling Load Intensity 1 Chiller 2 Chiller 3 Chiller 4 Chiller 24

1. Re-tune – Chiller Operation (cont’d) %Bypass Flow issue 25

1. Re-tune – Chiller Operation (cont’d) %Bypass Flow issue Bldg C 250% Percentage of Bypass Flow Rate 200% 150% Extra flow through bypass pipe 100% 50% 0% 0 20 40 60 80 100 120 Cooling Load Intensity 1 Chiller 2 Chiller 3 Chiller 4 Chiller 5 Chiller 26

2. Performance line evaluation Using thermal & electricity performance line COP keeps constant Consumption/Load COP increases at part load Consumption/Load Intensity Intensity Outdoor T emperature Outdoor T emperature COP decreases at part load Consumption/Load Intensity Outdoor T emperature 27

2. Performance line evaluation (cont’d) Using Coefficient of Performance line Coefficient of Performance (COP) COP = constant Cooling Load Intensity 28

2. Performance line evaluation (cont’d) Bldg D Bldg A 14 15 9 COP 10 VSD Air-cooled COP 4 VSD Water-cooled 5 CSD Air-cooled -1 0 20 40 60 80 100 120 0 Cooling Load Intensity 0 20 40 60 80 100 120 Cooling Load Intensity new chiller Old Chiller Bldg C Bldg E 14 14 12 10 9 COP 8 COP 6 4 4 CSD Air-cooled 2 CSD Water-cooled 0 -1 0 20 40 60 80 100 120 0 20 40 60 80 100 120 Cooling Load Intensity Cooling Load Intensity Note: Not sufficient data for Building B (No COP data),

1. Summary of Common Problems on Chiller Plant Systems Common Problems on Chiller Plant Systems Bld A Bld B Bld C Bld D Bld E Chillers Improper chiller sequencing  *    Serious chiller deterioration   Pumps (chilled water flow) Low/improper bypass valve setting      Deviation on chilled water flow rates across each  chiller Primary variable flow design but not fully in  N/A N/A N/A  operation Cooling towers High approach temp  N/A N/A *One chiller is sufficient to provide cooling over a year 30

1. Summary of Re-tuning Work Suggested Re-tuning Work Bld A Bld B Bld C Bld D Bld E Chillers Reduce chiller operation (N-1) to achieve higher *1 *2    overall COP *2 Increase Tcws    Max. demand shedding      Pumps (chilled water flow) Re-tune bypass valve setting    Install differential pressure sensors at the critical   path *2 Install VSD on the existing chilled water pumps N/A   N/A Cooling towers Reactive cooling tower (CT) optimisation N/A N/A  N/A  *1 One chiller is sufficient to provide cooling over a year *2 Serious chiller deterioration  limited improvement 31

1. Saving Summary of Re-tuning Work Suggested Re-tuning Work Bld A Bld B Bld C Bld D Bld E Chillers Reduce chiller operation (N-1) to achieve higher 5-6% 3-5% 3-5% *1 *2 (Actual) (Potential) (Potential) overall COP 1-3% 1-3% 1-3% *2 Increase Tcws (Potential) (Potential) (Potential) 0-1% 1-3% 0-1% 1-2% 0-1% Max. demand shedding (Potential) (Potential) (Potential) (Potential) (Potential) Pumps (chilled water flow) 1-3% 1-3% 1-3% Re-tune bypass valve setting (Potential) (Potential) (Potential) Install differential pressure sensors at the critical 1-3% 1-3% path (Potential) (Potential) 3-5% 3-5% *2 Install VSD on the existing chilled water pumps N/A N/A (Potential) (Potential) Cooling towers 1-3% 1-3% Reactive cooling tower (CT) optimisation N/A N/A N/A (Potential) (Potential) *1 One chiller is sufficient to provide cooling over a year *2 Serious chiller deterioration  limited improvement 32