Building Energy Saving through Life-Cycle Optimization, Commissioning and Diagnosis Experiences in International Commerce Center (ICC) of Hong Kong

Transcription

1 SinBerBEST Annual Meeting, 09-10, Jan, 2013, Singapore Building Energy Saving through Life-Cycle Optimization, Commissioning and Diagnosis Experiences in International Commerce Center (ICC) of Hong Kong Shengwei Wang Chair Professor of Building Services Engineering Building Energy and Automation Research Laboratory, Institute of Sustainable Urban Development/Department of Building Services Engineering The Hong Kong Polytechnic University 1

2 Outline of Presentation Basic approaches for building energy saving Life-cycle diagnosis/commissioning and optimization Technologies and deliverables Research areas and expertise Application Case 1 ICC Application Case 2 A Hotel Building Recent existing Building Energy Projects 2

3 Basic Approaches for Energy Efficient Buildings Reduced heating/cooling loads Building envelope design, passive design, etc. Use of energy efficient building systems and technologies Optimization of system and technology integration, operation and control Life-cycle commissioning, design optimization, control optimization, etc. 3

4 Team s Research Objectives and Applicable Deliverables Life-cycle Diagnosis/Commissioning and Optimization 4

5 Objectives of Diagnosis/Commissioning and Optimization Objective of Diagnosis/Commissioning To ensure the operation performance of the systems delivered meet the design intent. Objective of optimization To push the operation performance of the systems delivered to approach the best, often exceed the design intent. 5

6 Steps towards Energy Efficient Buildings Operation Stage and T&C Stage Push systems approach the best Ensure systems operate as good as intent Construction Stage Construct/install systems correctly Design Stage Optimize designs and selections Make designs proper and correct 6

7 Contents of Diagnosis/Commissioning and Optimization 7

8 Content of Diagnosis/commissioning Deviations of performances of a deliverable from its design intent come from different sources at different stages, diagnosis and commissioning should cover different stages: Design configuration; Component selection and sizing; Installation; (Monitoring and control) instrumentation; Test and commissioning; Operation and control; Maintenance, etc. Design Intent vs Deliverable 8

9 Content of Optimization Optimization of HVAC&R systems Optimization could be performed at different stages allowing the systems to provide expected quality of services (comfort and health environment) with reduced (minimum) energy consumption by means of: Optimizing design configuration; Optimizing selection and sizing; Optimizing (monitoring/control) instrumentation; Optimal operation and control, etc. 9

10 Technologies and Deliverables 10

11 Examples of Technologies Building Performance Quick Evaluation and Diagnostic Tool Detailed Evaluation and Diagnostic Tool for A/C and BA systems Building System Online Performance Simulation Test Platform Existing Building Commissioning and Upgrading Assessment Tool BA Control and Diagnosis Strategy Online Test Platform Package of Online Optimal and Energy Efficient Control and Fault Diagnosis Strategies Intelligent Building Integration and management Platform-IBmanager Both new building development and Existing Building Energy Saving are the targets. 11

12 Building Life-cycle Diagnosis, Commissioning and Optimization - International Commerce Centre (ICC) 12

13 Our Roles in ICC Project Independent Energy Consultant (Independent Commissioning Agent) 490 m 118 F To Develop the HVAC Energy Optimal Control System 13

14 Twb&Tdb Mw,tot & Trtn Tsup Npu Tw,rtn & Mw Mw Tw,out Tw,sup Mw Mw & Tw,in Nhx Mw Load Mw,&w,in Tw,rtn & Mw Nhx Mw & PDmeas Mw & PDmeas Mw & PDmeas Ma,i&Ta,in On/Off of AHUs Tw,sup On/Off of AHUs On/Off of AHUs Tw,sup Tw,sup Tw,sup Virtual Building System Dynamic simulation platform of the complex HVACR system Mw,i Pump & network TYPE 13 Freq PID control TYPE 43 Data Reader TYPE 9 On/Off of AHUs Pump sequence TYPE 39 HX sequence TYPE 39 Nhx Npu Nhx AHUs TYPE 21 Tao,i PID control TYPE 20 VPi PD optimizer TYPE 7 PDset Mixing TYPE 60 Tw,in &Mw HX modeling &mixing TYPE 41 Pump & network TYPE 14 Freq Mw,meas Tw,out PID control Mw,set PID control TYPE 43 TYPE 43 1 Zone 1 Return pipe TYPE 31 Chiller sequence controller TYPE 50 Cooling tower controller TYPE 3&54&55 Tw,out,i On/Off,i&Freq,i Load & status of AHUs TYPE 49 Zone 2 Mw & Tw,rtn Mw,tot & Tw,rtn Chiller One TYPE 23 On/Off of AHUs Ma,i&Ta,in Pump & network Mw,i TYPE 12 Freq PID control TYPE 43 Pump sequence TYPE 39 Chiller Two TYPE 23 Chiller Three TYPE 23 Chiller Four TYPE 23 Mixing after chiller condensers TYPE 4 Chiller Five TYPE 23 Chiller Six TYPE 23 CTA One TYPE 1 CTA Two TYPE 1 CTA Three TYPE 1 CTA Four TYPE 1 CTA Five TYPE 1 CTA Six TYPE 1 CTB One TYPE 2 CTB Two TYPE 2 CTB Three TYPE 2 CTB Four TYPE 2 CTB Five TYPE 2 Tw,out & Mw Tw,out & Mw Tw,out & Mw Tw,out & Mw Tw,out & Mw Tw,out & Mw Tw,out & Mw Tw,out & Mw Tw,out & Mw Tw,out & Mw Npu Mw & Tw,rtn Mixing after cooling towers TYPE 5 AHUs TYPE 63 Tao,i PID control TYPE 42 VPi PD optimizer TYPE 6 PDset Mixing TYPE 48 Mw & Tw,rtn Mixing & Bypass TYPE 67 On/Off Load & status of AHUs of AHUs Virtual Building On/Off of AHUs Ma,i&Ta,in TYPE 35 Pump & network Mw,i AHUs On/Off of AHUs Ma,i&Ta,in TYPE 17 TYPE 63 Mw,i Pump & network AHUs Freq Tao,i TYPE 18 TYPE 63 PID control PID control Freq Tao,i TYPE 43 TYPE 42 System PID control PID control Simulated VPi TYPE 43 TYPE 42 Pump sequence Npu PD VPi optimizer TYPE 39 TYPE 62 Pump sequence Npu PD PDset optimizer TYPE 39 TYPE 8 HX sequence Mixing Load PDset TYPE 39 TYPE 47 BA & Nhx Pump & network HX modeling HX sequence Mixing Mw &mixing TYPE 39 Nhx TYPE Zones Strategies 47 3&4 TYPE 15 TYPE 36 Freq Mw,meas Tw,in Pump sequence HX modeling &mixing TYPE 39 PID control TYPE 37 TYPE 43 Mw Npu Tw,sup Mw,set &Mw Pump & network PID control Mixing & TYPE 16 TYPE 43 bypass Freq Mw,meas Tw,out TYPE 19 (updated PID control Mw,set throughout PID control Pump the sequenceentire TYPE 43 TYPE 43 TYPE 39 Tw,rtn & Mw Mixing & bypass Tw,sup & Mw TYPE 45 Zone 3&4 Supply pipe TYPE 31 Tw,ch,out Tw,ch,out Tw,ch,out Tw,ch,out Tw,ch,out Tw,ch,out Nch On/Off On/Off On/Off On/Off On/Off On/Off Nch Tw,cd,out Tw,cd,out Tw,cd,out Tw,cd,out Tw,cd,out Tw,cd,out Mw,tot&Tw,ct,in Zone airflow rates Zone 2 Mixing TYPE 61 Tw,rtn & Mw,tot Mw,tot&Tw,ct,out Tw,cd,out Tsup process) Tw,cd,in TYPE XX: T: M: Load: Freq: N: VP: PD: Subscript w: meas: ao: in: rtn: cd: ct: hx: wb: Water Air outlet Inlet Return Component type number Temperature Water or air flow rate Cooling load Frequency Number Condenser Valve position Pressure differential Measurement Cooling tower Heat exchanger Wet-bulb a: i: tot: pu: set: ch: Set-point Chiller out: Outlet sup: Supply db: Air Individual Total Pump Dry-bulb

15 Commissioning at Design Stage Design commissioning mainly concerns the future operation and control performance of HVAC systems, including: Verifying/improving the system configuration and component selection including the chiller system, water system (primary/secondary system), heat rejection system (cooling towers), fresh air system etc. Verifying and improving the metering system for proper local control, and the original proposed control logics at the design stage. Proposal of additional metering system for implementing supervisory control and diagnosis strategies and related facilities for implementing these strategies

16 An Example of Diagnosis and Optimization at Design Stage

17 From Zone 3&4 To Zone 3&4 (S-B) (S-B) (S-B) (S-B) (S-B) (S-B) (S-B) System Design Verification and Optimization Secondary water loop systems of 3 rd /4 th zones A HX-06 FROM PODIUM & BASEMENT TO PODIUM & BASEMENT SCHWP to 12 HX-06 (S-B) (S-B) SCHWP to 02 A B C D E F B Secondary water circuit for Zone 1 Secondary water circuit for Zone 2 Secondary water circuit for Zone 3 and Zone 4 Primary water circuit Chiller circuit Cooling water circuit FROM OFFICCE FLOORS(7-41) TO OFFICE FLOORS(7-41) SCHWP to 05 C FROM OFFICE FLOORS (79-98) TO OFFICE FLOORSS (79-98) SCHWP to 03 PCHWP PCHWP PCHWP HX-78 HX-78 HX-78 SCHWP to 06 FROM OFFICE FLOORS (43-77) TO OFFICE FLOORS (43-77) SCHWP to 03 PCHWP PCHWP PCHWP PCHWP PCHWP PCHWP PCHWP HX-42 HX-42 HX-42 HX-42 HX-42 HX-42 HX-42 SCHWP to 09 SCHWP to 03 HX-78 HX-78 SCHWP to 06 HX-78 (S-B) (S-B) FROM OFFICE FLOORS (79-98) TO OFFICE FLOORSS (79-98) Flow meter Bypass valve FROM OFFICE FLOORS (43-77) TO OFFICE FLOORS (43-77) SCHWP to 03 D PCHWP PCHWP PCHWP PCHWP PCHWP PCHWP HX-42 HX-42 HX-42 HX-42 HX-42 HX-42 HX-42 E EVAPORAROR EVAPORATOR EVAPORATOR EVAPORATOR EVAPORATOR EVAPORATOR WCC-06a-01 (2040 Ton) WCC-06a-02 (2040 Ton) WCC-06a-03 (2040 Ton) WCC-06a-04 (2040 Ton) WCC-06a-05 (2040 Ton) WCC-06a-06 (2040 Ton) F CONDENSER CONDENSER CONDENSER CONDENSER CONDENSER CONDENSER CDWP CDWP CDWP CDWP CDWP CDWP SCHWP to 09 From cooling towers To cooling towers Primary pumps are omitted Original System Revised System

18 Pump power (kw ) Comparison between Two systems Original design Alternative design Typical sunny-summer day Time (h ) Annual Pump Energy Saving is 1M kwh/ 水泵年节能量为 1 百万 kwh

19 Optimal control strategies for central air-conditioning systems Chiller sequence, optimal start Optimal chiller sequence - based on a more accurate cooling load prediction using data fusion method, and considering demand limiting Adaptive online strategy for optimal start - based on simplified subsystem dynamic models Ventilation strategy for multi-zone air-conditioning system Optimal ventilation control strategy - based on ventilation needs of individual zones and the energy benefits of fresh air intake Peak demand limiting and overall electricity cost management 19

20 Optimal control strategies for central air-conditioning systems Chilled water system optimization Optimal pressure differential set point reset strategy Optimal pump sequence logic Optimal heat exchanger sequence logic Optimal control strategy for pumps in the cold water side of heat exchangers Optimal chilled water supply temperature set-point reset strategy Cooling water system optimization Optimal condenser inlet water temperature set point reset strategy Optimal cooling tower sequence 20

21 Optimal Control of Variable Speed Pumps Speed control of pumps distributing water to heat exchangers Secondary side of HX From terminal units To terminal units Temperature set-point Temperature controller T T HX HX M M Modulating valves Primary side of HX ΔP From cooling source To cooling source Original implemented strategy differential pressure control and by resorting to the modulating valve Temperature set-point Temperature controller Pressure differential set-point Differential pressure controller To terminal units Secondary side of HX From terminal units TM T HX HX Primary side of HX TM From cooling source To cooling source Revised strategy cascade controller without using any modulating valve Temperature set-point Temperature controller Water flow set-point Water flow controller 21

22 Performance test and evaluation Site practically tests show that the proposed strategy can provide stable and reliable control. Compared to original implemented strategy, about 22.0% savings for pumps before heat exchangers in Zone 1 was achieved. Due to the low load of Zone 1 in ICC at current stage, a simulation test of annual energy savings by using PolyU strategy is performed Energy consumption (kwh) Pumps Number Original Alternative Saving (standby) strategy Strategy (kwh) (kwh) (kwh) heat Primary exchanges pumps in Zone 1 due to the 1(1) use of 528, ,132 71,876 Primary pumps for Zones 3&4 3(1) 921, , ,405 Primary pumps in Zone 4 2(1) 401, ,420 54,588 Total saving of the primary pumps 251,869 Energy saving of primary pumps before PolyU strategy is about 250,000 kwh. 22

23 Visible Plume Abatement 23

24 Visible Plume 24

25 Visible Plume Abatement Normal operation when there is no predicted plume occurs Decision maker Platform for predicting plume occurring possibility Operation modes Cooling Water Temp Setpoint Operating Condition Cooling Tower Number Cooling Tower Freq At first-level warning, increase airflow rate by 20% when plume potential is marginal At second-level warning, increase airflow by 40% when plume potential is high Start heating using heat pumps when visual plume is observed Chiller Power Power Consumption Cooling Tower Power Total Power Additional energy consumption for plume control could Difference C - Hz kw kw kw kw % Reference be reduced from % 3 to 5.5% or % at 59.1 low Load First-level warning Second-level warming Using heat pumps CT+1HP

26 Chiller Plant Sequencing Control of Enhanced Robustness using Data Fusion Technique 26

27 Cooling Load Measurement based on Data-Fusion Cooling load measurement Direct measurement of building cooling load Q dm = c pw ρ w M w (T w,rtn -T w,sup ) c pw is the water specific thermal capacity; ρ w is the water density; M w is water flow rate; T w,rtn,t w,sup are chilled water return/supply temp. Indirect measurement of building cooling load Q im = f(p com,t cd,t ev ) P com is chiller power consumption; T cd,t ev are chiller condensing/evaporating temperatures 27

28 Robust building cooling load measurement technique Based on Data Fusion Data fusion to merge Direct measurement and Indirect measurement improving the accuracy and reliability of building cooling load measurement Data Fusion Engine Q load (Fused cooling load) r load (Degree of confidence) Q dm Direct Load measurement Q in,1 Chiller Model 1 + Q in,n Chiller Model n Advanced soft measurement system T sup M w W ch,1,t ev,1,t cd,1 W ch,n,t ev,n,t cd,n T rtn Chiller 1 Chiller n Central Chilling Plant 28

29 Robust Chiller Sequencing Control Based on Enhanced Cooling Load Measurement Technique High degree of confidence => Accurate and relatively aggressive control Medium degree of confidence => Less aggressive and safer control Low degree of confidence => Safe control and warning for maintenance check 29

30 Summary of Energy Benefits 1,000,000 kwh energy consumption is saved due to the modification Saving on the by secondary Commissioning water loops of (Improving Zone 3 & 4 the system configuration and selection) compared with the 2,360,000 kwh, (about 5.1% of annual energy consumption of original chillers design. and cooling towers) About of the cooling 3.5 M system per year The annual total energy can be saving due to the change from single speed to variable speed using VFD saving is about 7.0M kwh! 607,000 kwh, (about 2.8% of annual energy consumption of chillers and cooling towers) of the cooling system will be wasted when the lowest frequency is limited at 37 Hz Saving by Control Optimization compared with the case when the HVAC system operates correctly as the 3, 500,000 kwh (about 7%) of the total energy consumption of original HVAC system) design can intent. be saved using PolyU 3.5M control per strategies year based on the original design 30

31 Contributions in supporting ICC building in getting HK-BEAM Platinum Certificate The overall assessment grade is based on the percentage of applicable credits (about 145) gained in 5 categories: site aspects, material aspects, energy use,water use, and IAQ (vision 4/04 ). Grade Overall Performance Platinum 75% Excellent Gold 65% Very Good Silver 55% Good Bronze 40% Above average H V A C Annual Energy Use Reduction By 14.6% to get extra 2 credits Peak Demand Reduction By 26.9% to get extra 2 credits Optimal Control Strategies Innovation for extra 1 credits Platinum 76.2%) 5 credits (3.5%) Gold 72.7%)

32 A New Hotel Development in Sheung Wan (Holiday Inn Express) Independent Energy Consultant (Independent Commissioning Agent) To Develop the HVAC Energy Optimal Control System

33 Summary of Energy Benefits Saving by Commissioning (Improving the system configuration and selection) and Control Optimization compared with the case when the HVAC system operates correctly as the original design intent. 20% saved annually 33

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