Existing Building Energy Saving
Ir Cary Chan Executive Director, HK Green Building Council
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Aviation industry
1903
1930s
1969
1981
1971
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4
5
6
7
A big gap to fill
Convincing responses to your boss !
Deliver !
Energy Management Process
Implementation of energy management
DATABASE
POLICY
OBJECTIVE & TARGET
ACTION PLAN
AUDIT
MEASUREMENT & VERIFICATION
REVIEW MEETING & REPORT
ANALYSIS
ACT
PLAN
IMPLEMENTATION DO
CHECK
Knowledge-based
DIAGNOSIS (Retro-Cx)
BENCHMARKING
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Design parameters
Load calculation
System design
Equipment selection
Testing 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
Type Composite Hotel Composite (Podium+
Towers) Composite (Office
+Education)
Office (Industrial Building
Renovation)
Age (Yrs) 25 41 24 20 20
IFA (sqm) ~20,000 ~36,000 ~150,000 ~4,500 ~45,000
Chiller 4x320TR
Water-Cooled (new)
4x180TR Water-cooled 4x190TR Air-cooled
(new)
7x1000TR Water-cooled
2x400TR Water-cooled(Night)
1x150TR Air-cooled 1x150TR Air-cooled
(new)
4x400TR Air-cooled
Cooling Tower 4 4 6+2 N/A N/A
Control Differential Pressure Bypass
Differential Pressure Bypass
Differential Pressure Bypass
Differential Pressure Bypass
Differential Pressure Bypass
Pumps 4+1 Water-cooled: 4 Air-cooled: 4+1
7+2 4+2 (Office Tower) 2+1 4+1
Features Variable Speed Chiller
140TR Heat Pump for hot water
Heat Exchanger for high rise office tower
natural ventilation allowed
Fresh air treated by FCU
.
Availability of data and information varies !
Approach and Method
Has to consider : • Practicality • Minimum provision of instrument • Availability of data and information
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“ACT-Shop” – Data Analysis Method (retro-Cx)
2. Performance line evaluation 3. Peak demand shedding
Outdoor Ambient Temperature
Load
ing
Valv
e A
utho
rity
24:00
Peak
Dem
and
0:00
summer
winter
Con
trol
Set
-poi
nt
Re-tune: • Discharge valve • Double regulating
valve, etc.
Cooling Load
%lo
ad
100%
Re-tune: 1. DTCHWS 2. DTA 3. DSP
2
3
1.1
1.2
1.3
6
Outdoor Ambient Temperature
Cooling load
4. Set-point reset
1. Re-tune 1.1 Valve authority 1.2 Set-point 1.3 Equipment operation
4. DPWS 5. TAPP,C 6. TAPP,C
T
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““ACT-Shop” – Data Analysis Method (retro-Cx)
Bldg A Bldg B Bldg C Bldg D Bldg E DTCHWsummer DTCHWwinter
5.0°C 2.5°C
5.0°C 3.2°C
5.0°C 3.0°C
2.5°C 0.75°C
3.4°C 2.0°C
TCHWSsummer TCHWSwinter
7.8°C 10°C
7°C 11°C
8°C 9.5°C
9.5°C 14°C
8.5°C 10°C
COP,CHsummer COP,Chwinter
6.3 13
3.3 3.4
5.3 4.2
3.2 2.9
1.6 2.5
EUI(Chiller)
60 kWh/m2/year
115 kWh/m2/year
88 kWh/m2/year
33 kWh/m2/year
48.3 kWh/m2/year
Low COP
Low DTCHW
TCHWS reset at winter
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1. Re-tune – Chiller Operation
Cooling Load/m2
Perc
enta
ge o
f Ful
l Loa
d A
mpe
re (%
FLA
)
3 Chillers Zone
2 Chillers Zone
1 Chiller Zone
100% Full Load
• Good operation • Poor operation (high % full load ampere due to deterioration of chiller
capacity)
More FLA
Less FLA
Extra chiller
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1. Re-tune – Chiller operation (cont’d) % Full Load Ampere issue
0%
20%
40%
60%
80%
100%
0 20 40 60 80 100 120Perc
enta
ge o
f Ful
l Loa
d A
mp
Cooling Load Intensity
Bldg C
1 Chiller 2 Chiller 3 Chiller 4 Chiller 5 Chiller
0%
20%
40%
60%
80%
100%
0 20 40 60 80 100 120
Perc
enta
ge o
f Ful
l Loa
d A
mp
Cooling Load Intensity
Bldg E
1 Chiller 2 Chiller 3 Chiller 4 Chiller
Extra chiller in operation
Chiller operate at high % FLA
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1. Re-tune – Chiller Operation (cont’d) Delta T of Chilled Water issue
Del
ta T
of C
hille
d W
ater
3 Chillers Zone
2 Chillers Zone
1 Chiller Zone
Delta T of Chilled Water Design Value
Cooling Load/m2
• Good operation • Poor operation (narrow delta T due to excessive flow
through chillers or bypass pipe)
Large Delta -T
Small Delta-T
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1. Re-tune – Chiller Operation (cont’d) Delta T of Chilled Water issue
0.0
1.0
2.0
3.0
4.0
5.0
6.0
0 20 40 60 80 100
Del
ta T
of C
hille
d W
ater
(°C
)
Cooling Load Intensity
Bldg B
1 WCC 0.5ACC + 0.5WCC
One chiller capacity but two pumps
0.01.02.03.04.05.06.0
0 20 40 60 80 100 120
Del
ta T
of C
hille
d W
ater
(°C
)
Cooling Load Intensity
Bldg E
1 Chiller 2 Chiller 3 Chiller 4 Chiller
Extra flow through chiller
0.0
1.0
2.0
3.0
4.0
5.0
6.0
0 20 40 60 80 100 120
Del
ta T
of C
hille
d W
ater
(°C
)
Cooling Load Intensity
Bldg C
1 Chiller 2 Chiller 3 Chiller 4 Chiller 5 Chiller
Extra flow through bypass pipe
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1. Re-tune – Chiller Operation (cont’d) %Bypass Flow issue
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1. Re-tune – Chiller Operation (cont’d) %Bypass Flow issue
0%
50%
100%
150%
200%
250%
0 20 40 60 80 100 120
Perc
enta
ge o
f Byp
ass F
low
Rat
e
Cooling Load Intensity
Bldg C
1 Chiller 2 Chiller 3 Chiller 4 Chiller 5 Chiller
Extra flow through bypass pipe
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2. Performance line evaluation Using thermal & electricity performance line
Con
sum
ptio
n/Lo
ad
Inte
nsity
Outdoor Temperature
COP keeps constant
Con
sum
ptio
n/Lo
ad
Inte
nsity
Outdoor Temperature
COP increases at part load
Con
sum
ptio
n/Lo
ad
Inte
nsity
Outdoor Temperature
COP decreases at part load
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2. Performance line evaluation (cont’d) Using Coefficient of Performance line
Cooling Load Intensity
Coe
ffici
ent
of P
erfo
rman
ce (C
OP)
COP = constant
2. Performance line evaluation (cont’d)
VSD Water-cooled
0
5
10
15
0 20 40 60 80 100 120
CO
P
Cooling Load Intensity
Bldg A
CSD Water-cooled
-1
4
9
14
0 20 40 60 80 100 120
CO
P
Cooling Load Intensity
Bldg C
CSD Air-cooled
02468
101214
0 20 40 60 80 100 120
CO
P
Cooling Load Intensity
Bldg E
Note: Not sufficient data for Building B (No COP data),
CSD Air-cooled -1
4
9
14
0 20 40 60 80 100 120
CO
P
Cooling Load Intensity
Bldg D
new chiller Old Chiller
VSD Air-cooled
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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 operation
N/A N/A N/A
Cooling towers
High approach temp N/A N/A *One chiller is sufficient to provide cooling over a year
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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 overall COP
*1 *2
Increase Tcws *2
Max. demand shedding
Pumps (chilled water flow)
Re-tune bypass valve setting
Install differential pressure sensors at the critical path
Install VSD on the existing chilled water pumps N/A *2 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
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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 overall COP
5-6% (Actual)
*1 3-5% (Potential)
*2 3-5% (Potential)
Increase Tcws 1-3% (Potential)
1-3% (Potential)
*2 1-3% (Potential)
Max. demand shedding 0-1% (Potential)
1-3% (Potential)
0-1% (Potential)
1-2% (Potential)
0-1% (Potential)
Pumps (chilled water flow)
Re-tune bypass valve setting 1-3% (Potential)
1-3% (Potential)
1-3% (Potential)
Install differential pressure sensors at the critical path
1-3% (Potential)
1-3% (Potential)
Install VSD on the existing chilled water pumps N/A 3-5% (Potential)
3-5% (Potential)
*2 N/A
Cooling towers
Reactive cooling tower (CT) optimisation N/A N/A 1-3% (Potential) N/A 1-3%
(Potential)
*1 One chiller is sufficient to provide cooling over a year *2 Serious chiller deterioration limited improvement
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1. Payback 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 overall COP
<1 year *1 3-5 year *2 <1 year
Increase Tcws <1 year <1 year *2 <1 year
Max. demand shedding <1 year <1 year <1 year <1 year <1 year
Pumps (chilled water flow)
Re-tune bypass valve setting <1 year <1 year <1 year
Install differential pressure sensors at the critical path
<1 year <1 year
Install VSD on the existing chilled water pumps N/A 3-5 year 3-5 year *2 N/A
Cooling towers
Reactive cooling tower (CT) optimisation N/A N/A <1 year N/A <1 year
*1 One chiller is sufficient to provide cooling over a year *2 Serious chiller deterioration limited improvement
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make the most out of the next Energy Audit
Review and identify improvements needed from last audit : Quality of measurement , methodology , robustness of data , value of data, readiness of building operators and REA..etc Learn where to focus
Setting a foundation for the future : New requirements for data and information for future management, tracking and analysis ( for buildings, industry and government) Useful O&M manual Benchmarking Building capacity ( building provisions, knowledge , specially trained REA.. ) Central data center Setting up energy management systems
Performance Assessment Development of KPI (Air conditioning)
Performance Assessment - KPI benchmarking
Performance Assessment -KPI benchmarking
Performance Assessment - KPI benchmarking
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Case Study: Problem in Air Handling Unit
Always open
Always close
Diagnosis
Are our systems working?
Hotels New Development Commercial Bldgs
Existing Bldg A 145
136 (50th%)
2011
2016
How do we compare with others? Opportunities
Benchmarking
Long Term Planning
Can we have a 10-year plan?
Saving = 9,858kWh/year
Saving Estimation
ANALYSIS How much can you save?
Knowledge-Based Energy Management
Sensors
Analysis Useful Information
Utilise Information
•Facilitate Research •Implement Initiatives
Data
Tr
ansm
issi
on
Data Bank
BMS Always close
Saving Estimation M&V Method
Fault Diagnosis Long Term Planning
Opportunities
Characteristic
Sources: Swire Properties Ltd
Action Research
Difficulties
Lack of market drives • Not aware benefit
of using data
Software not user friendly • Proprietary product
High investment • Cost not directly
justified • Product upgrade • Staff training
Data missing • Massive data
transmission and storage problem
Inaccurate data • Sensor
malfunction/ improper location & error
Inconsistent data format • Bldg. Mgt. Systems
& power metering systems not interoperable
Lack of support • Not much demand
Inadequate hardware • Power meter / Flow
meter / DP sensors on equipment/ system base
DATA
FACILITIES
BUSINESS
Lack of Specification • There is no any
requirement and standards for reference
ACT-shop
Knowledge - Why Operating Data Not Commonly Used?
Barriers
Collaboration issues within the Industry
Owner Designer
Operator Contractor
•Inadequate drives for knowledge based management •Focus on project cost only
•Lacks BMS/PMS/DMS expertise •Lacks O&M experiences
•Shortage of construction time •Inadequate T&C and re-commissioning concept
•Focus on services reliability for tenants •Lack of interest and capabilities in performance analysis
Manufacturer
•Focus on functional operation needs only •Value of information management not emphasis •Lacks of interest in O&M market •Emphasis on cost competitiveness
ACT-shop
Output Input Efficiency =
Key Performance Indicators DATA INFORMATION
How Efficient is Our Plant?
BMS BMS BMS BMS
BMS BMS BMS BMS
BMS BMS BMS BMS
BMS BMS BMS BMS
BMS BMS BMS BMS
BMS BMS BMS BMS
BMS BMS BMS BMS
BMS BMS BMS BMS
BMS BMS BMS BMS
BMS BMS BMS BMS
BMS
BMS
BMS
BMS
BMS
Quality of Data •Accuracy •Right Form •Accessibility
Problems: •Missing data •Incorrect form of data •Huge data volume and scale •Incompetence in analysis
Technical Challenges
.
.
.
Run to Life Retrofit Knowledge transfer
Early Replacement
House keeping
General Practices & Regulatory Compliance
Optimization
Continuous Improvement
Chiller
Lighting
Advanced Control
Air-cool Water-cool
Lift Modernization
Retro-Cx
Metering
Work with stakeholders
Routine Inspection
Knowledge-Based Practice Adopt Best Practice Maintenance Requirement
Routine Maintenance
Mandatory Audit
O&M Manual
Basic Need
Saving ~17% Saving >24%
Transformation of the Current Industry
Building Operator • Government • Private Sector
Services Provider
In-house Competence
e-O&M Manual
Develop & drive the products / services markets
Saving
Business
knowledge
Beyond Standard
• Detailed databank • Develop competence within the
industry • Standardise energy analysing
method / format • Raise next energy audit standard • Robust benchmarking system
Industry HKIE BSOMES ASHRAE RICS…
Education VTC/IVE Universities
ACT
SHO
P
Establish Knowledge Sharing Platform
Analysis & Benchmarking (Opportunities?)
• Fault detection How Data Helps
• Time series analysis • Expert rules
Tool
Diagnosis (Any fault?)
• Fault detection How Data Helps
• Time series analysis • Expert rules
Tool
Case Study: Problem in Air Handling Unit
Case Study: Problem in Air Handling Unit Problem Verification
Case Study: Problem in Air Handling Unit
After problem solving
Re-tune (Implementation)
• Optimise operation How Data Helps
• Engineering Approach Tool
ΔT
ΔT , design = 5°C
Data of ΔT
high condensing differential temperature
Design
Real Operation
Underflow
7°C
Any Deviation?
Ente
ring Cooling
TowerCoolingTower
To BMS
P
PFlowcon
collectorcollector
1m
Leav
ing
Ente
ring Cooling
TowerCoolingTower
To BMS
P
PFlowcon
collectorcollector
1m
Leav
ing
Leav
ing
T
T
to remove the flow-con: • higher water flow rate • lower condensation temperature • higher chiller efficiency
Underflow
Increase pressure
Reduce resistance
More consumption
lower
7°C
4.5°C
Problem Identification & Rectification
kPa Riser A B C D E F
Critical AHU 33.5 35.2 37.4 37.8 35.5 35.8 Target 54 56 57 58 56 56
ΔP ΔP ΔP ΔP ΔP ΔP
Return
Supply
Riser A Riser B Riser C Riser D Riser E Riser F
Design
Real Operation
Vs.
Any Deviation?
Restricted by under-sized AUHs
Renovation of under-sized AUHs
A B C D E F Original 85 110 95 95 100 100
Step 1 85 110 90 90 100 100
Step 2 75 110 80 80 80 80
Step 3 70 80 70 70 70 70
Summer time exercise
Winter time ??
∆P reset Over pressurized
Problem Identification & verification
• Saving Estimation How Data Helps
• Regression model + BIN Method Tool
Saving Estimation, Measurement & Verification “Conversion from IGV to VSD control”
Retrofit – Saving Estimation
Retrofit – Measurement & Verification
Manufacturer claimed saving cannot be identified
Performance indicator to be verified against % loading at particular range of impact factor(s)
Energy Management – Long term Plan (Are we achieving our target?)
• Energy management reporting
How Data Helps
• Cumulative frequency plot Tool
Buildings in HK account for:
90% Total Electricity Consumption
60% Greenhouse Gas Emission
Existing Buildings account for
90% of HK Building Stock
Achievement and Target
Cost and Benefit
Database
Measurement and Verification
Condition 1
Condition 2
Condition 3
Did it work?