Existing Building Energy Saving

Ir Cary Chan Executive Director, HK Green Building Council

2

Aviation industry

1903

1930s

1969

1981

1971

3

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

10

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

19

“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

20

““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

21

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

22

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

23

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

24

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

25

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

26

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

28

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

30

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

32

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

33

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

34

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

40

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?