9/6/14 Professor Chandra Sekhar, National University of Singapore 1 Chandra Sekhar Professor, PhD, Fellow ASHRAE, Fellow ISIAQ Department of Building, School of Design and Environment ASHRAE Distinguished Lecturer Talk ASHRAE India Chapter New Delhi 18 June 2014 1.Describe an integrated IAQ-Energy audit methodology 2.Interpret the IAQ and Energy audit data from case studies in a hot and humid climate 3.Describe the key features of Thermal Comfort and Ventilation Standards (a) ASHRAE Standards 55 & 62.1 and (b) Singapore Standards 4.Describe the Singapore Green Mark Scheme for rating buildings for environmental sustainability Learning Objectives
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ASHRAE Distinguished Lecturer Talk - ASHRAE India · Professor, PhD, Fellow ASHRAE, Fellow ISIAQ Department of Building, School of Design and Environment ASHRAE Distinguished Lecturer
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9/6/14
Professor Chandra Sekhar, National University of Singapore 1
Chandra Sekhar Professor, PhD, Fellow ASHRAE, Fellow ISIAQ
Department of Building, School of Design and Environment
ASHRAE Distinguished Lecturer Talk ASHRAE India Chapter
New Delhi 18 June 2014
1. Describe an integrated IAQ-Energy audit methodology
2. Interpret the IAQ and Energy audit data from case studies in a hot and humid climate
3. Describe the key features of Thermal Comfort and Ventilation Standards (a) ASHRAE Standards 55 & 62.1 and (b) Singapore Standards
4. Describe the Singapore Green Mark Scheme for rating buildings for environmental sustainability
Learning Objectives
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Professor Chandra Sekhar, National University of Singapore 2
Energy Efficient Healthy
Buildings
Thermal Comfort
Energy GHG Reduction
IAQ
IAQ Scenario
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Mendell, M.J., W.J. Fisk, K. Kreiss, H. Levin, D. Alexander, W.S. Cain, J.R. Girman, C.J. Hines, P.A. Jensen, D.K. Milton, L.P. Rexroat and K.M. Wallingford, 2002. Improving the health of workers in indoor environments: Priority research needs for a national occupational research agenda. American Journal of Public Health, Vol 92, No.9, 1430 -1440.
…… improving building environments may result in health benefits for more than 15 million of the 89 million US indoor workers, with estimated economic benefits of $5 to $75 billion annually.
Benefits and costs of improved IEQ in U.S. offices
Scenarios • Increasing vent rates when below 10 or 15 l/s per person • Adding O/A economisers and controls when absent • Eliminating winter indoor temps >23°C • Reducing dampness and mold problems
Estimated Benefits • Increased work performance • Reduced SBS symptoms • Reduced absenteeism • Improved thermal comfort for millions of office workers
Combined potential annual economic benefit of a set of nonoverlapping scenarios ≈$20 billion
Quantitative estimates have a high uncertainty – BUT opportunity for substantial benefits is clear
Fisk, W. J., Black, D. and Brunner, G. (2011), Benefits and costs of improved IEQ in U.S. offices. Indoor Air, 21, Issue 5 : 357–367
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Max Joseph von Pettenkofer (1818-1901), german chemist
“If there is a pile of manure in a space, do not try to remove the odor by venGlaGon. Remove the pile of manure.”
IAQ - Source Control
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IAQ
Aud
it
OBJECTIVES OF AUDIT
• Establish status of Indoor Air Quality (IAQ)
• Identify strategies for improving IAQ • Basis for developing an IAQ audit and
management program
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Professor Chandra Sekhar, National University of Singapore 6
Sekhar SC, KW Tham and KWD Cheong, Indoor Air Quality And Energy Performance of Air-conditioned Office Buildings In Singapore, Indoor Air – International Journal of Indoor Air Quality and Climate, 2003, Volume 13, Issue 4, pp. 315-331.
Figure 11 : A comparison of MALE and FEMALE Building Related Symptoms (Mean of all five buildings) - Here and Now (%)
VENTILATION STUDIES IN NINE AIR-CONDITIONED OFFICE BUILDINGS IN
SINGAPORE
Period of Study : 1993 - 1997
Obj
ectiv
e M
easu
rem
ents
–
Vent
ilatio
n pa
ram
eter
s
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Factors affecting ventilation performance Ø space layout Ø fresh air quantity Ø supply diffusers and return grilles
Indoor air flow pattern Ø Short circuiting Ø Piston flow Ø Perfect mixing
Flow pattern affects • Indoor Air Quality (IAQ) • Building energy consumption
19
THE VENTILATION MODEL
Age-of-air L average amount of time elapsed since molecules in a sample entered the building • measured by tracer gas techniques "youngest" air found where the outdoor
air comes into the room –
"oldest" air found at any other point in the room
VENTILATION CHARACTERISTICS
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Professor Chandra Sekhar, National University of Singapore 11
l TRACER GAS MEASUREMENTS
l AGE OF AIR VALUES l LOCAL MEAN AGE OF AIR l ROOM AVERAGE AGE OF AIR
l AIR CHANGE RATE
l Air Exchange Effectiveness (also known as Ventilation Effectiveness)
type of tracers used usually colourless, odourless, inert gases (e.g. SF6)
Important aspect of TG measurements can be made in occupied buildings
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23
slope of the tracer gas concentration decay curve
Air Change per Hour (ACH)
Time
Trac
er G
as (p
pm)
Linear Plot
ACH = ln(C0 – ln(C1) Δt
Time
Trac
er G
as (p
pm)
Semi Log Plot C0, t0)
C1, t1)
Concentration-decay method
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Perfectly mixed air - datum for all three AEE parameters AEE = 1
the greater the deviations from unity, more pronounced are the two flow patterns
Air Exchange Effectiveness
25
Key building characteristics
Floor by Floor AHUs CAV system
A, C
Floor by Floor AHUs VAV system
B, D, E, BB, DD, EE
3 CentralAHUs VAV system
CC
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0 1 2 3 4
A
D
CC
ACH
Bui
ldin
g
Figure 1 : Summary of Air Change per Hour (ACH) values
0 5 10 15 20 25Fresh air provision (lps/person)
A
C
E
C C
E E
Bu
ild
ing
Figure 2 : Comparison of fresh air provision based on design occupancy
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Figure 5 : Comparison of Localised Air Exchange Effectiveness (AEEL) Values
0 0 . 5 1 1 . 5 2
A
C
E
C C
E E
Bu
ildin
g
AEEL
29
Conclusions – 9 Buildings Study
l Tracer gas analysis : In-situ ventilation measurements
l Significant variations in ACH values l Minor short-circuiting profiles in some
zones l AEE values generally indicative of well-
mixed flow patterns
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Particulate Better filtration
Replace carpets
Renovation - Close library Purging
Filtration (F/A Intake; AHU)
Equipment (Photocopiers;
Computer Clusters)
Carpets
Downwash zone + Door mats at entrance
Demand Control Ventilation
Causes Pollutants Recommendations
Occupant Density
Demand Control Ventilation
Replace carpets TVOCs/ Formaldehyde
Photocopiers (separate exhaust) Computer clusters
Equipment (Photocopiers;
Computer Clusters)
Carpets
Fresh Air Provision
Renovation Purging
Filtration (F/A Intake; AHU)
Total Bacteria Total Y&M
Occupant Density
Fresh Air Provision
AHU-installed Bacteria Killers
Fresh air filter into AHU
Carbon Dioxide
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SPORE
GREECE
UK
SWISS
GERMAN
FRANCE
FINLAND
NORW
AY
DENM
ARK
8
6
4
2
0
Nordic Climate
Continental Europe
Trop
ical
C
limat
e
Oce
anic
Eu
rope
Mediterranean Europe
Air
chan
ge ra
tes
(h-1
)
Air change rates (ACH) measured in the European and Singapore buildings studied
Zuraimi MS, Roulet C-A, Tham KW, Sekhar SC, David Cheong KW, Wong NH & Lee HK, 2004. “A comparative study of VOCs in Singapore and European Office Buildings”, Building and Environment, Volume 41, Issue 3, March 2006, Pages 316-329
VENTILATION & IAQ ISSUES IN SPLIT SYSTEM
AIR-CONDITIONING UNIT IN A RESIDENTIAL BUIDLING
IN SINGAPORE
Year of study : 2002/2003
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“B”
“C”
P1
Exha
ust
Fan
Window
Multi-Split system Fan Coil Unit
6.36 m
2.90 m
1.73
m
3.15
m
“A” “B”
“C”
Bed-Head Built-in wardrobe
Built-in W
ard-robe (floor-to-ceiling)
1.08
m
Master Bed-room in a condominium apartment (8th Storey) 35
18:00 06:0000:00
500
1000
1500
2000
2500
3000
3500
4 Adults (Experiment Phase)
Exhaust fan switched on
CO
2C
once
ntra
tion
Leve
l (pp
m)
Time
2 Adults, 1 Child – SleepingPeriod during night
CO2 concentration during measurement and night-time sleeping periods 36
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Thermal Comfort VenGlaGon and
IAQ
Standards 37
SSPC 55 to maintain and revise Standard 55. Standard on continuous maintenance. Standard 55 placed on continuous maintenance January 24, 2004 (Anaheim). SSPC 55 authorized 1/26/1994.
Current version –
ASHRAE Standard
55-2013
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Thermal Comfort
Operative temperature
Humidity - No lower limit - 0.012 kg/kg upper limit
Elevated Air Speed
Local thermal discomfort
Radiant temperature discomfort
Draft
Vertical Air Temperature Difference
Floor surface temperature
Temperature variations with time
Cyclic variations (15 minutes
interval)
Drifts or Ramps (non-cyclic
changes - > 15 mins)
ASHRAE Standard 55-2010 39
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41
Occupant controlled NV
spaces
Operable windows – open to outdoors
No mechanical
cooling system
Mech Vent with unconditioned air
possible
Allows for local
thermal discomfort in typical buildings
Accounts for people’s clothing adaptation in NV
spaces
No humidity or air speed
limits required
Adaptive model – global database of 21,000 meas – primarily in office buildings
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43
VRP • Prescribes rates &
procedures based on typical space contaminant sources & source strengths
IAQP • Requires calculation of
rates based on analysis of contaminant sources, concentration targets and perceived air quality targets.
ASHRAE Standard 62.1
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62.1-2013 Purpose
Specify minimum ventilation rates &
other measures – to provide IAQ
acceptable to occupants &
minimise adverse health effects
Regulatory applications to new
buildings and additions
Guidance for IAQ improvement in
existing buildings
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Acceptable Indoor Air
Quality
air in which there are no known contaminants at harmful
concentrations as determined by cognizant authorities and with which a substantial majority (80% or more)
of the people exposed do not express dissatisfaction
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Green Building Standard
l Published in January 2010
l Serves as benchmark for sustainable green buildings – does not apply to all buildings
l Addresses energy, impact on the atmosphere, sustainable sites, water use, materials and resources and IEQ
l Jurisdictional compliance option for International Green Construction Code
www.ashrae.org/greenstandard 47
Standard 189.1
l Standard for Design of High-Performance Green Buildings
l An ANSI standard developed in model code language
l Provides minimum requirements for high-performance, green building
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Standard 189.1 Topic Areas
SS
WE
EE
IEQ
MR
CO
Sustainable Sites Water Use Efficiency Energy Efficiency Indoor Environmental Quality Building’s Impact on the Atmosphere, Materials & Resources Construction and Operations Plans
49
SS 553 : 2009 Code of Practice for Air-conditioning and Mechanical Ventilation in Buildings (formerly CP 13)
SS 554 : 2009 Code of Practice for Indoor Air Quality for Air-Conditioned Buildings
Published November 2009 50
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Table 1 – Outdoor air supply requirement for comfort air-conditioning
ASHRAE Std 62.1-2010 (l/s/person)
5.1 10.3 8.5
7.8/7.6/7.8
2.7
2.7
3.5
5.5
4 – 7.4
8.6
SS 553 : 2009
51
Energy Scenario
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0.0
200.0
400.0
600.0
800.0
1,000.0
1,200.0
1,400.0
1,600.0
2004 2010 2015 2020 2025 2030
239.8 254.4 265.2 275.1 285.9 298.0
206.9 256.7 294.2 331.9 367.7 403.5
446.7 511.1
559.4 607.0
653.6 701.6
Qua
drill
ion
Btu
Total Non-OECD OECD
57%
95% 24%
World Marketed Energy Consumption by Region, 2004-2030
Sources : 2004 – EIA, International Energy Annual 2004 (May-July 2006), Projections – EIA, System for the Analysis of Global Energy Markets (2007)
0.0
5.0
10.0
15.0
20.0
25.0
2004 2010 2015 2020 2025 2030
18.3 19.7
21.0 22.1 23.3 24.6
6.2 8.7
10.8 12.5
14.3 16.1
Qua
drill
ion
Btu
OECD Non-OECD
Commercial and Services sectors – includes different building types • Office buildings, schools, stores, correctional institutions, restaurants, hotels, hospitals, museums, banks, stadium
OECD and Non-OECD Commercial Sector Delivered Energy Consumption, 2004-2030
Green Mark Assessment Criteria
New Buildings -‐ New Dev -‐ Redevelopment -‐ A&A to exisGng buildings -‐ Major retrofiWng
ExisGng Buildings -‐ Under operaGon with no significant retrofiWng works
BCA – Building and ConstrucGon Authority, Singapore 54
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Points for Green Mark Criteria
BCA Green Mark for Non-Residential Building Version 4.1
BCA Green Mark Schemes DescripGon EffecGve Date Non-‐Residen-al New Buildings (Version 4.1)
Applicable for new buildings such as offices, commercial, industrial and ins-tu-onal buildings with or without air-‐condi-oning systems.
15 Jan 2013 onwards
Residen-al New buildings (Version 4.1)
For new private and public residen-al developments. 15 Jan 2013 onwards
Exis-ng Buildings (Version 3)
Applicable to exis-ng commercial, industrial and ins-tu-onal buildings under opera-on.
26 Jul 2012 onwards
Exis-ng Buildings (Version 2.1)
Applicable to exis-ng commercial, industrial and ins-tu-onal buildings under opera-on. Assessment by this criteria is necessary for applica-on of GMIS (Exis-ng Building).
1 Dec 2009 onwards
Exis-ng Residen-al Buildings (Version 1)
For exis-ng private and public residen-al developments. 19 May 2011 onwards
Exis-ng Schools (Version 1)
Applicable to MOE main stream schools (excluding Interna-onal schools, Universi-es and Ins-tute of Higher Learning: Polytechnics and ITE).
4 Aug 2011 onwards
Office Interior (Version 1.1) Applicable for tenant renova-on and maintenance prac-ces. 01 Nov 2012 onwards
Landed Houses (Version 1) For landed housing projects. 27 May 2009 onwards
Infrastructure (Version 1) For infrastructure projects e.g. as barrages, roads, bridges. 27 May 2009 onwards
District (Version 2) For district projects. 01 Jan 2013 onwards
Restaurants (Version 1) For Restaurants. 12 Sep 2011 onwards
Supermarket (Version 1) For Supermarket. 11 Oct 2012 onwards
Exis-ng Data Cetres (Version 1
For Exis-ng Data Cetres. 11 Oct 2012 onwards
Retail (Version 1 For Retail Tenants. 11 Oct 2012 onwards
New Parks (Version 1) For New Parks 26 May 2010 onwards
Exis-ng Parks (Version 1) For Exis-ng Parks 22 may 2008 onwards 56
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Green Mark Points Green Mark RaGng
90 and above Green Mark PlaGnum GMIS Req → Energy Modeling →
At least 30% Energy Savings
85 to < 90 Green Mark GoldPLUS GMIS Req → Energy Modeling →
At least 25% Energy Savings
75 to < 85 Green Mark Gold
50 to < 75 Green Mark CerGfied
Green Mark Award Rating Version NRB 4.1, 15 Jan 2013
57
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21% 0% 80%
2004 Sept 2013 2030
PERCENTAGE OF GREEN BUILDINGS IN SINGAPORE
59
NATIONAL LIBRARY BUILDING
KEY GREEN FEATURES • Building orientated away from the E-W sun - sun shading features west face of building • Energy efficient features - daylight sensors with automatic blinds at the building facades,
motion sensors & energy efficient lightings • An open plaza area between the two blocks - allows natural ventilation and daylighting • Extensive landscaping, sky terraces and roof gardens - to lower local ambient temp • Rain sensor - part of the automatic irrigation system for rooftop gardens. Water efficient
taps & cisterns used to conserve water
• 16-storey state-of-the-art library with a 3-level basement
• two blocks - library collections - space for other public activities
• a 618-seat theatre • owner’s commitment at
conceptualisation stage - design considerations : impact on environment, energy and water efficiency.
• Computer simulation & modeling - to find the best bldg orientation & confign - buffer from direct solar heat & optimising natural vent & daylighting.
• passive design solutions with env-friendly technologies
2005 Green Mark PlaGnum
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Key Features: • Sunshading devices and efficient glazing. • ACMV System (high performance chillers, displacement ventilation, personalised
ventilation, under-floor air distribution system). • Photovoltaic Technology of 190kWp capacity. • Solar assisted stack ventilation. • Mirror ducts, light pipes and light shelves. • Sensors and monitoring system for all rooms.
Key Features: • Estimated energy
savings: 388,720 kWh/yr
• Estimated water savings: 3,620 m3/yr
• ETTV: 43.79 W/m2
2010 Green Mark Platinum
(Non-Residential New Buildings)
Zero Energy Building @ BCA Academy (Special Buildings)
2012 Green Mark Platinum
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2013
63
2013
64
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2013
65
2013
66
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2013
67
IAQ & Energy Issues
Impact of ventilation and IAQ on
occupant productivity and health
IAQ Audit – IAQ parameters, Ventilation
parameters, Human Response
Final Words
Energy Scenario
Relevant Standards
Integrated IAQ Energy Assessment
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