Building Energy Issues and the COVID-19 ResponseYong Siew Hwa, PE, CEM
9 November 2020 EBC Building Energy Codes Working Group Annual Symposium
Buildings in the Tropic rely on Air-Conditioning to provide thermally comfortable working environment for occupants
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temperature to set within 23°C – 25°C and relative
humidity <70%
as much as 50% of the building’s total energy
consumption.
Chiller plant equipment accounts for as much as
70% of the cooling system energy consumption.
Chart1
50%
Lift
12%
Lighting
13%
Equipment
5%
Others
20%
To resize chart data range, drag lower right corner of range.
Raise Energy Efficiency Standards for Central Chilled-Water Plant
Water cooled chilled water system
Green Mark Rating
Building Cooling Load (RT) <500 RT ≥500RT Minimum Efficiency (kW/RT)
Certified 0.85 0.75 Gold 0.8 0.75 0.70
GoldPLUS 0.75 0.7 0.68 Platinum 0.7 0.68 0.65
Air cooled chilled water system
Green Mark Rating
Certified 1.1 1.0 Gold 1.0
*N.AGoldPLUS 0.85 Platinum 0.78
a) BCA Green Mark
Performance Based Procurement for Maintenance
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Regular maintenance and optimisation of the cooling system is critical to ensure that it continues to operate efficiently
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Applies to (i) Buildings with planning submission date on or after
1 Dec 2010 and were approved under Building Control (Env Sus) Regulations 2008
(ii) Buildings that were approved for major energy use change under Building Control (Env Sus Measures for Existing Buildings) 2013
Exclude any industrial buildings; residential, railway premises, airport and port services, religious buildings, utilities and data centres
Mandatory Periodic Energy Audit of Central Chilled-Water Plant Efficiency
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START
Building Owner appoints a professional to carry out Audit
PE(Mech)/EA ensure M&V and Audit comply to Code and submit to BCA
Issues notice of Approval
Building Owner appoints a professional to carry out Audit
Issues notice of Approval
PE(Mech)/EA ensure M&V and Audit comply to Code and submit to BCA
YEAR 6
Building Owner appoints a professional to carry out Audit
Issues notice of Approval
PE(Mech)/EA ensure M&V and Audit comply to Code and submit to BCA
YEAR 9 …
Building Owner appoints a professional to carry out Audit
Issues notice of Approval
PE(Mech)/EA ensure M&V and Audit comply to Code and submit to BCA
RESTART
AVERAGE ANNUAL CHILLER PLANT EFFICIENCY IN KW/TON (C.O.P.) (Input energy includes chillers, condenser pumps, tower fans and chilled water pumping)
New Technology All-Variable Speed
Older Chiller Plants
Chiller Plants with Correctable Design or Operational Problems
Based on electrically driven centrifugal chiller plants in comfort conditioning applications with 42F (5.6C) nominal chilled water supply temperature and open cooling towers sized for 85F
(29.4C) maximum entering condenser water temperature and 20% excess capacity. Local Climate adjustment for North American climates is +/- 0.05 kW/ton
kW/ton C.O.P.
Compliance Standards (Minimum Operating System Efficiency (OSE))
Ext’g Building, baseline @ 0.80 kW/ton, building load > 500RT
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Imposing requirements for Permanent Accurate M&V instrumentation for determining Operating System Efficiency & Long –term Monitoring
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• Provision of permanent measuring instruments for monitoring water-cooled central chilled-water plant efficiency. The overall measurement system shall have the capability to calculate resultant plant efficiency (i.e. kW/RT) with the uncertainty within 5% for in-situ measurements.
• In addition, the following must be complied with:
• Location and installation of the measuring devices to meet the manufacturer’s recommendation; location of temperature sensors within reach to facilitate site verification.
• All data logging devices with capability to trend at 1 minute sampling time interval and recorded to the 3rd decimal digit
• Flow meters to be provided for chilled water and condenser water loop and shall be of full bore magnetic in-line flow meter. If installation of magnetic in-line meters is not possible, ultra flow meters may be used.
• Temperature sensors to be provided for chilled water and condenser water loop and the measurement system shall have an end-to-end uncertainty not exceeding ± 0.05 °C over the entire measurement or calibration range. Provisions shall be made for each temperature measurement location to have two spare thermo-wells located at both side of the temperature sensor for verification of measurement uncertainty.
• Dedicated digital power meters (of IEC Class 1 or better) and metering current transformers (of Class 1 or better), shall yield power based on root-mean-square (RMS) current, RMS voltage and power factor for each group of equipment i.e. chillers, chilled water pumps, condenser water pumps, cooling towers. VSDs should not be used as the losses are not accounted for.
• Computation and display of air-side efficiency, water-side efficiency and total system efficiency.
Standards for Permanent Instrumentation
Air distribution Efficiency
Baseline 0.28 kW/RT
Air Distribution SystemNew
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
0.18 0.19 0.22 0.23 0.24 0.24 0.26
0.28 0.29 0.30 0.32 0.33
0.35
BCA Smart Chiller Portal
New
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Buildings in the Tropic rely onAir-Conditioning to provide thermally comfortable working environment for occupants
Energy Consumption of Chiller Plants
Raise Energy Efficiency Standards for Central Chilled-Water Plant
Energy Efficient Design and Installation Practices
Performance Based Procurement for Maintenance
Mandatory Periodic Energy Audit of Central Chilled-Water Plant Efficiency
Statutory Requirements(Audit Cycle for New Buildings)
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Air Distribution System
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