ASHRAE Distinguished Lecturer Talk - ASHRAE India · Professor, PhD, Fellow ASHRAE, Fellow ISIAQ Department of Building, School of Design and Environment ASHRAE Distinguished Lecturer

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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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

7

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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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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 (%)

0

5

10

15

20

25

30

35

40

45

Building Related Symptoms

Per

cent

age

of o

ccup

ants

ex

peri

enci

ng s

ympt

oms

Total Female Male

Total 30 26 29 30 17 27 7 13 10 15 10 3

Female 40 32 35 42 21 33 7 16 12 19 13 5

Male 14 19 14 10 10 18 6 11 8 8 4 0

Dryeye Blocknose Drythroat Dryskin Headache Lethargy Wateryeye Runnose Chesttight Flusymp Rash Other

Que

stio

nnai

re S

tudy

Acceptability of Indoor Air Quality (% Dissatisfied) - A Comparison of Singapore and EU studies

0.0%

5.0%

10.0%

15.0%

20.0%

25.0%

30.0%

35.0%

40.0%

45.0%

German

y

Singap

ore

Switzerl

and

Finlan

d

France

United

King

dom

The N

etherl

ands

Greece

Denmark

Norway

Countries

% D

issa

tisfie

s

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Figure7 : Indoor air acceptability versus thermal comfort

y = 2.877x - 0.7754R2 = 0.8529

y = 3.6399x - 2.0058R2 = 0.8499

1

2

3

4

5

6

7

8

9

10

1 2 3 4

Thermal Comfort (1-4)

IAQacc

Clearly Acceptable

Clearly not acceptable

ComfortableVeryUncomfortable

Just notacceptable

Just acceptable

"Now"

"Past month"

Figure 11 : A comparison of MALE and FEMALE Building Related Symptoms (Mean of all five buildings) - Here and Now (%)

0

5

10

15

20

25

30

35

40

45

Building Related Symptoms

Per

cent

age

of o

ccup

ants

ex

peri

enci

ng s

ympt

oms

Total Female Male

Total 30 26 29 30 17 27 7 13 10 15 10 3

Female 40 32 35 42 21 33 7 16 12 19 13 5

Male 14 19 14 10 10 18 6 11 8 8 4 0

Dryeye Blocknose Drythroat Dryskin Headache Lethargy Wateryeye Runnose Chesttight Flusymp Rash Other

Figure 9 : Indoor air acceptability versus stuffiness

y = 1.3945x - 1.5936R2 = 0.9385

y = 1.1797x - 0.4819R2 = 0.8136

12

345

678

910

1 2 3 4 5 6 7

Stuffiness (1-7)

IAQacc

Clearly Acceptable

Clearly not acceptable

Fresh Stuffy

Just notacceptable

Just acceptable "Now"

"Past Month"

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DIMENSIONS OF INDOOR AIR QUALITY

•  Chemical •  Biological •  Physical

Obj

ectiv

e M

easu

rem

ents

–

IAQ

par

amet

ers

CHEMICAL •  Sources

–  Interior furnishings –  Equipment –  Stationery –  Outside sources

•  Particular chemicals –  TVOCs –  Formaldehyde –  Carbon Monoxide –  Carbon Dioxide

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BIOLOGICAL

•  Sources –  Occupants –  Visitors –  Food –  Outside sources

•  Particular contaminants –  Total Bacteria –  Yeasts & Molds

0 200 400 600 800 1000 1200 1400 1600 Total Bacteria (CFU/m3)

A A

B B

C C

D D

E E

Gui

delin

e va

lue

= 50

0 C

FU/m

3 Occupant level

Air supply level

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

18

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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

20

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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

22

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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

24

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Perfectly mixed air - datum for all three AEE parameters AEE = 1

AEEG = 2.0 "perfect" displacement flow

AEEG < 1.0 shortcircuiting AEEG > 1.0 displacement flow

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

28

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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

34

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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

38

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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

40

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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

42

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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

44

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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

45

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

46

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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

48

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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

15 January 2013

http://www.bca.gov.sg/GreenMark/green_mark_criteria.html

55

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

58

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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

60

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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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Documents

ASHRAE Distinguished Lecturer Talk - ASHRAE India · Professor, PhD, Fellow ASHRAE, Fellow ISIAQ Department of Building, School of Design and Environment ASHRAE Distinguished Lecturer