1. technology and computing
2. data centers

SS 591 : 2013
Long Term Measurement of Central
Chilled Water System Energy Efficiency
Adapted for SEI/PSS
30March2015
Lee Eng Lock
Co-convenor of SS 591 : 2013 Working Group
Overview of SS 591 : 2013
Purpose
Enable an organization to design and implement a measurement and
verification (M&V) system for the long term, continuous and accurate
tracking of the energy efficiency of central chilled water systems;
The objectives of long term, continuous and accurate tracking of energy
efficiency, important process parameters and relevant performance data
of central chilled water systems are to:
•
Ensure correct sizing of plant components;
•
Facilitate proper operation, maintenance, sizing, and control of the system to improve
energy efficiency, and to reduce greenhouse gas emissions and water consumption;
•
Allow buyers to specify energy efficiency requirements that must be met and
guaranteed by suppliers, Energy Services Companies (ESCOs), contractors, and
designers of equipment and systems; and
•
Facilitate the reporting of the performance of the chilled water system to relevant
authorities.
Information on this slide is confidential and strictly for use by SPRING Singapore officers only. It should not be used or referred to by third parties without prior written consent from SPRING Singapore.
2
Overview of SS 591 : 2013
Main clauses
Section
Content
1.
General
•
•
•
Scope
Normative references
Definitions
2.
Description of measurement and
verification system
•
•
•
General (Annex A)
Data points
Performance metrics (Annex B)
3.
Measurement and instrumentation
requirements
•
•
•
Uncertainty and calibration
Installation (Annex C)
Instrument documents (Annex D)
4.
Data handling and presentation
•
•
•
Data point naming (Annex E)
Trending & storage
Graphics display
5.
Testing and commissioning
•
•
•
•
Checks on installation
Demo/ witness test
Verification
Training & submittals (Annex F)
6.
Long term and continuous monitoring
•
•
•
Monitoring procedures
Instrument service life
Maintenance checklist
3
Overview of SS 591 : 2013
References

ASHRAE Guideline
14:2002
Measurement of energy and demand savings

IEEE 519:1992
IEEE Recommended practices and requirements for harmonic control in
electrical power systems

IEC 61869-2:2012
Instrument transformers - Part 2: Additional requirements for current
transformers

IEC 61869-3:2011
Instrument transformers - Part 3: Additional requirements for inductive
voltage transformers

IEC 61869-5:2011
Instrument transformers - Part 5: Additional requirements for capacitor
voltage transformers

IEC 62053-22:2003
Electricity metering equipment (a.c.) - Particular Requirements - Part 22:
Static meters for active energy (classes 0,2 S and 0,5 S)

ISO 4185:1980/Cor
1:1993
Measurement of liquid flow in closed conduits-weighing method

ISO 8316:1987
Measurement of liquid flow in closed conduits- method by collection of the
liquid in a volumetric tank

ISO/IEC 17025:2005
General requirement for the competence of testing and calibration
laboratories

SS ISO 50001 : 2011
Energy management systems- Requirements with guidance for use
Information on this slide is confidential and strictly for use by SPRING Singapore officers only. It should not be used or referred to by third parties without prior written consent from SPRING Singapore.
4
Overview of SS 591 : 2013
Section Two – clause 2.2 Data points
• Lists the data points where measuring instruments shall be supplied and installed to monitor at 1 minute
interval and trended over the entire life-cycle of the chilled water system.
Minimum Requirements
Temperature
CHW & CDW Header
return/supply temperature
Flow
CHW & CDW Header flow
Power
Group of equipment (chillers,
CHW & CDW pumps and cooling
towers)
Weather
Station
Dry-bulb air temp and RH
Minimally 1 set along the cooling
towers
Recommended Requirements
Temperature
CHW & CDW return/supply
temperature at individual chillers
Flow
CHW & CDW flow at individual
chillers
Power
Power at individual equipment
Minimum requirement
5
Overview of SS 591 : 2013
Section Three – clause 3.1.2 Uncertainty under laboratory conditions
• Provides the uncertainty of each measurement system as well as the overall uncertainty under
laboratory conditions
Measurement System
(includes sensor and
data acquisition system)
Maximum allowable uncertainty (%)
(calibration under laboratory condition)
Each temperature measurement system: ±0.05⁰C.
Between the supply and return of the chilled or condenser water:
Temperature
(0.05 C)2  (0.05 C)2

5.5 C
Flow
Power
 100%  ± 1.3
±1
±2
Overall maximum allowable uncertainty of the M&V system :
Overall
1.32  12  22 
± 2.6
*Recommends that the calibration facilities meet the requirements of ISO/IEC 17025: 2005
6
Overview of SS 591 : 2013
Section Three – clauses 3.1.4 to 3.1.6 Requirements for each measurement system
• Provides the uncertainty requirements and testing standards for each measurement system –
temperature, power and flow
Measurement System
Important clauses
Temperature
Each temperature sensors shall be individually calibrated against a
measurement standard with a maximum uncertainty rating of ±0.01⁰C.
Flow
All tests conducted to measure the uncertainty of the flow measurement
system shall be in accordance with ISO 4185:1980/Cor 1:1993, ISO
8316:1987 or equivalent test standards.
Type-test reports can be accepted as long as they demonstrate that the
requirements in 3.1.5.3 (above) have been met.
Power
All tests conducted to measure the uncertainty of power meters and their
associated current and voltage transformers used in the power measurement
system shall be in accordance with applicable test standards, i.e. IEC 6205322:2003 for power meters, IEC 61869-2:2012 for current transformers and
IEC 61869-3:2011/IEC 61869-5:2011 for voltage transformers. Equivalent
test standards can also be adopted.
Type-test reports can be accepted as long as they demonstrate that the
requirements in 3.1.6.3 (above) have been met.
7
Overview of SS 591 : 2013
Section Three – clause 3.1.7 Data acquisition system
• Provides the requirements of the data acquisition system
Measurement System
Important clauses
The data acquisition system shall be able to record and store values up to
at least 3 decimal places.
Data acquisition system
The memory space of the data acquisition system shall be sized for at
least 36 months of storage capacity.
8
Overview of SS 591 : 2013
Section Three – Clause 3.2 Installation & set-up
• Provides the minimum installation and set-up requirements for each measurement system
Flow meter
Temp sensors
Power meters
• Installed at the incoming side
of the VSD
Wiring
• All measuring and control
cables to have common
screen
For magnetic flow meters
• Insertion types
• Installed in thermowells
• Test plugs before and after
each temp sensor
• Screens of control cables
shall be connected to
earthing points and from
there, to the indoor earthing
rings
9
Overview of SS 591 : 2013
Section Four – clause 4.2 Data point naming convention
• Provides the name architecture and naming rules for the data points monitored by the
BMS/EMS
Description
Chilled water flow rate
Chilled water system
Chilled water pump
Chilled water return temperature
Chilled water supply temperature
Chiller
Common header
Condenser pump
Condenser water flow rate
Condenser water return temperature
Abbreviation
CHWF
CHWSYS
CHWP
CHWRT
CHWST
CH
HDR
CDWP
CDWF
CDWRT
Condenser water supply temperature
CDWST
Cooling tower
CT
Heat Exchanger
HX
Power
KW
Primary chilled water pump
PCHWP
Secondary chilled water pump
SCHWP
10
Overview of SS 591 : 2013
Section Four – clause 4.3 Trending
• Provides the list of data points to be trended in the BMS/EMS
Minimum Requirements
Clause 2.2: Data points
Clause 2.3: Performance metrics
CHW and CW header return/supply
temperature
System cooling load
CHW and CW header flow
Power input to groups of equipment (chillers,
CHW & CDW pumps, cooling towers)
Dry-bulb air temp and RH
Minimally 1 set along the cooling towers
Supply chilled water temp
Temperature difference between chilled
water supply and return
Heat rejected
Heat balance substantiating test
COP of chilled water system
Chilled water system energy efficiency
Equipment energy efficiency
11
Overview of SS 591 : 2013
Section Four – clause 4.5 Graphics Display
• Provides the requirements of the graphics display of the BMS/EMS
Minimum Requirements
• Sensor’s location and their dynamic values at 2 d.p.
• Operating status of key equipment
• Summary of set points
• Instantaneous values of:
• Total cooling load and total condenser water tonnage
• Total power consumed by each group of equipment (chillers, CHW &CDW
pumps and cooling towers)
• System energy efficiency and COP
• Equipment energy efficiency
• Instantaneous and cumulative values of total electrical energy consumed by the
system
• System heat balance
Recommended Requirements
• Individual chiller energy efficiency
• Consistency checks (if instrumentation are installed at individual equipment level)
12
Overview of SS 591 : 2013
Section Six – clause 6.1 Monitoring Procedures
• Recommends the procedure that the owner can adopt in monitoring the performance and
accuracy of the M&V system
Post-installation monitoring
conducted through
BMS/EMS
Heat balance substantiating
test
Multipoint consistency
check
Use highly accurate
portable instruments
In the event that any of the instruments does not tally with the
verification instrument, it is recommended to replace or
recalibrate the instrument.
13