Incorporating Occupant Behaviour Into New Building Design · 2014. 7. 28. · Occupant behaviour is...
Transcript of Incorporating Occupant Behaviour Into New Building Design · 2014. 7. 28. · Occupant behaviour is...
Incorporating Occupant
Behaviour Into New
Building Design
Liam O’Brien, PhD Assistant Professor, Civil & Environmental Engineering
PI, Human Building Interaction Laboratory
Carleton University
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12 Ottawa House Load Comparison
Non-HVAC: Appliances, lighting, hot water
(Saldanha, Beausoleil-Morrison, 2012)
Factor
of 4
# of occupants is a
reasonable good
predictor; but hard to
predict during design
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Background
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5 identical Danish houses; Source: Gram-Hanssen (2010)
• Family #3 thought they were
very energy-conscious
4 Assumed occupant behaviour affects design
5 Occupant Behaviour and Passive Buildings
Occupant behaviour is even more significant
in passive buildings
Occupant Uncertainty and NZEB Design
Energy Use
Pro
bab
ility Renewable energy generation
capacity for 50% chance of achieving net-zero energy
90% chance of achieving net-zero energy
Uncertainty from occupant behaviour
Occupant effects: 10 to 1000%
7 Manual Shade Control
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Uncertainty about blinds control
(Christoph Reinhart, 2004)
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9 Understanding Occupant Shade Control
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8 9 10 11 12 13 14 15 16
Me
an S
had
e P
osi
tio
n (F
ract
ion
C
lose
d)
Time of Day
South East
South West
North East
North West
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10 Understanding Occupant Shade Control
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“Seduced by the View”
(Urban Green Council, USGBC, 2013)
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What’s been said of occupants:
are illogical
act in response to random, external events
take decisions to use switches or controls only after an event has
prompted them to do so (rather than in advance of it)
often wait for some time until taking action and typically when they
reach a ‘crisis of discomfort’
over-compensate in their reactions for relatively minor annoyances
take the easiest and quickest option rather than the best, for their
immediate benefit
consciously or otherwise, leave systems in their switched state,
rather than altering them back again later, at least until another crisis
of discomfort is reached.
Leaman (1999)
Path of Least Resistance: “Desire Path”
Occupants will take the path of least
resistance, so we might as well consider
this from the beginning of design.
Results from a survey on residential
blind use
(Veitch, Mancini, Galasiu, Laouadi, 2013)
IAQ
Thermal
Comfort
Acoustic
Comfort
Visual
Comfort Privacy
Quality
of View Activity
Type Social
Constraints
Past
Experiences
Anticipated
Conditions
Occupancy
Type
Clothing
Level
Light-
switching
Fan use Operable
windows MacGyvered
solutions
Reposition
& Rotate Change
Activity Level Eat/drink
Thermostat
Adjustment
Cost
Implications
Environmental
Conscience
Energy
Literacy
Ease of
Adaptation Systems’
Simplicity
Black
Box
Culture
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Agenda
1. Background theory
2. Case studies that exemplify occupant
behaviour
3. Three-tiered approach
1. Design with passive features
2. Implement smart controls
3. Directly influence occupant behaviour
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Comfort is key: thermal, visual, acoustic
Thermal
Comfort
Acoustic
Comfort
Indoor Air
Quality
Visual
Comfort
Energy
Fixe
d a
nd
mo
vab
le
sola
r sh
adin
g
Heating/cooling
Heating/cooling
Daylightin
g
design
Openness for daylight penetration
Ventilatio
n and
outdoor a
ir
require
ments
Surf
ace
fin
ish
es: d
ust
co
llect
ing
vs. s
ou
nd
ab
sorb
ing
Natural ventilation
and outdoor noise
Acoustics is repeatedly ranked low for green buildings
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Occupants are Creative
If discomfort occurs, occupants will adapt
themselves or the building
The Human Energy Balance
2/1/2014 20
ASHRAE Comfort Chart
2/1/2014 21
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Adaptive Comfort
(only applies to buildings with natural/hybrid ventilation)
23 EcoTerra EQuilibrium House, Eastman, QC
2.84 kW (peak)
Building-
integrated
photovoltaic-
thermal system
Passive solar
design:
Optimized
triple glazed
windows and
mass
Ground-
source heat
pump
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Don’t ignore localized comfort
Comfort is more than air temperature.
ASHRAE recommends concrete/tile floors to be maintained at 26-29°C if
they are likely to be stood on with bare feet.
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Other occupant adaptations
Dark shades
significantly
reduce heat-
rejection
capability
Can be
thermally
worse than no
shades at all
26 Know your occupants: anticipate diversity
Design for flexibility. Example: EcoTerra
Garage was turned into a workshop
Basement was converted to bedroom
Occupants are retired (not middle-aged with two
kids)
5 kW electric heater
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Education of occupants was critical
EcoTerra garage
heater
EcoTerra setpoints
NREL RSF
cleaning schedule
But we must rely
less on researcher
intervention!
Plug loads add up
Heat Pump21.3%
DHW11.7%
HRV/Air Cleaner
7.2%
BIPV/T Fan & Pump1.4%
Aux Garage Heater7.3%
Controls2.2%
Aux HP Heater1.0%
Lighting, Appliances, Plug Load
34.5%
Fan, Misc Equip13.2%
EcoTerra house Average existing
Canadian house
Second fridge and freezer in
EcoTerra basement
EnerPos, Reunion Island, France
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Seek efficient means
to deliver comfort
(Garde and Lenoir)
No significant air-conditioning required
Comfort can be maintained through natural ventilation and fan use alone
(Garde and Lenoir)
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Comfort is key: thermal, visual, acoustic
EnerPos clothing level
ASHRAE recommends 0.5 clo in summer; 0.34
clo was measured in EnerPos
Open
windows
allow both air
and sound
through
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Load monitoring in EnerPos
Equipment cost about 3% of
the total building costs
After 6 months of operation, it
was discovered that 13% of
EnerPos’ energy use was for
the elevator!
Why? The lighting.
ASHRAE Comfort Tool
NREL RSF, Golden, Colorado
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RSF Interior Design
Photography or Photorealistic
Renderings for Visual Comfort Analysis
So
urc
e: B
ren
t H
uch
uk
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Comfort and energy are tightly linked
Thermal
Comfort
Acoustic
Comfort
Indoor Air
Quality
Visual
Comfort
Energy
Fixe
d a
nd
mo
vab
le
sola
r sh
adin
g
Heating/cooling
Heating/cooling
Daylightin
g
design
Openness for daylight penetration
Ventilatio
n and
outdoor a
ir
require
ments
Surf
ace
fin
ish
es: d
ust
co
llect
ing
vs. s
ou
nd
ab
sorb
ing
Natural ventilation
and outdoor noise
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Acoustic Comfort
Acoustic comfort
is routinely
ranked low in
green buildings.
Hard surfaces
Open concept
Low ventilation
rates
Natural ventilation
Acoustic Comfort
Newsham, Birt, Arsenault, Thompson, Veitch, Mancini, Galasiu, Gover, Macdonald, Burns (2012)
Design for comfort and occupant
behaviour
But no future opportunities for adjustment; so get it right!
Occupant
Behaviour
Smart Controls
Fixed/Passive Design
Design for comfort and occupant
behaviour
But extreme care must be taken to not irritate occupants
Design for comfort and occupant
behaviour
But disaggregate as much as possible
Occupant
Behaviour
Smart Controls
Fixed/Passive Design
Robust Design
System (building) Deviation
from target
Signal
Noise (e.g., occupant
behaviour)
Design parameters
Definition: An engineered system that is
designed to have greater tolerance for a wide
range of conditions while still performing as
desired.
Fixed/Passive Design
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Bi-directional robust design
BuildingOperating conditions
Occupant(s)
Performance
Comfort conditions
Adaptive actions
PO(x)
x
PB(x)
x
PP(x)
x
POC(x)
x
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Robust Design Example
Variation on Lightswitch-2002 algorithm to reflect observed inactivity of occupants
Shades closed if Isolar,workplane > 50 W/m2 and solar penetration depth > 1.0 m
Reopen after X days, where X is a normal distribution (μ = 3 days; σ = 3 days) if occupant is present
Lights are controlled to achieve 500 lux or greater on workplane
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0.8 m
Glare-free zone 3.0 m
3.0 m
Ωmin for no glare
Solar noon,
June 21Ωmax
= 70° Fixed shading device
1.0 m
Robust Design
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Robust Design
50
10 %
Robust Design
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Robust Design
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0.8 m
Glare-free zone 3.0 m
3.0 m
Ωmin for no glare
Solar noon,
June 21Ωmax
= 70° Fixed shading device
1.0 m
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Interior Design: Chair
An upholstered chair can add about 0.2 clo
(equivalent level to thin pants)
This shifts the comfort temperature by about
1.1°C
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Interior Design: Desk A computer monitor that is perpendicular to a
window is theoretically optimal for daylight
glare prevention.
(Osterhaus, 2005)
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Interior Design: Desk One study found that giving occupants full
range of rotation eliminated daylight glare for
97% of occupied time.
Sample Robust Design Solutions
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Occupants have diverse
preferences
Traditional controls neglect
these and assume “one-size-
fits-all”
They are also conservative to
prevent complaints
Controls can be designed to
learn from occupant
override/habits
Reinhart and Voss (2003)
Design
guidelines
Desig
n g
uid
elin
es
Haldi and Robinson (2010)
Occupant
Behaviour
Smart Controls
Fixed/Passive Design
Smart Controls
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Example of learning controls: Nest
The Nest thermostat
Learns your schedule
Learns your preferred
temperature
Attempts to make slight
energy-saving shifts unless
override occurs
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Smart Controls does not necessarily
mean complex
Occupancy sensors for
perimeter offices often
increase energy use over
manual switch. Why? If conditions are sufficiently daylit,
people may not turn their lights on. This
more than compensates for those who
forget to turn them off at end of day.
A simple switch can reduce lighting
energy by 60% relative to occupancy
sensors
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Perceived control and social dynamics
Cohen et. al (1998):
manual controls
(windows, blinds,
lights) in open-plan
offices tend to “lapse
into default states that
minimize conflict and
inconvenience but are
not optimal, e.g. ‘blinds
down, lights on.’”
Social dynamics play an important role
in comfort and behaviour
Clothing level
Lights
Shades/blinds
Fans
Thermostats
Noise/speech
Private office Open-plan office
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Perceived Control vs. Actual Control
Studies have shown that people are much more comfortable if they sense they are control, even if they are, in fact, not.
Ideally, people should have the power to easily control their comfort.
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http://redchalksketch.wordpress.com/category/facade/facade-
consultant/emmer-pfenninger-partner-ag/
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Perceived control and social dynamics
Bordass, Bromley, Leaman (1993). User and occupant controls in office buildings
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Approaches to individualized comfort
CBE, UC Berkeley
Personal fan at head level
Hands heater above keyboard
Foot heater Task lighting
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Building energy
billing systems are
like going grocery
shopping without
being able to see
the prices till after
check-out. –
Source unknown
Occupant
Behaviour
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Occupant Feedback
Thermostat misconceptions
(Urban, 2013)
Thermostat is an on/off
switch
Thermostat is a dimmer
switch
Thermostat is an accelerator
Turning down the thermostat
has little or no effect on
energy consumption
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Influence of sub-metering on indoor
temperature selection
Upgrading homes to
submetering reduces
energy use by ~30%
Submetering added
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Influence of sub-metering on indoor
temperature selection
Submetered
occupants were less
willing to take further
adaptive measures:
they were at their
comfort limit
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Building Dashboard Guidelines
Provide context (historical and/or
understandable metrics)
Sub-meter as much as possible –
individuals must see their personal
impact
Real-time or frequent updates
Interactive
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Validation for Adaptive Actions
Window opening signals can
“…validate and leverage the
behavior of those who
naturally like to have their
windows open.” - Ackerly and Brager, 2011
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Energy Savings and Clothing Level
If occupants have
minimal constraints on
clothing level, heating
and cooling energy can
be reduced by as much
as 40%! (Newsham,
1997)
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Clothing Level and Social Constraints Shopping Mall:
Offices:
Morgan and de Dear (2003)
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Clothing Level and Social Constraints
Casual Friday in the office:
Morgan and de Dear (2003)
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Japanese Cool Biz initiative
Initiative to increase A/C setpoint to 28°C
Allow staff to wear less formal clothes
Use of desk fans
Flextime to avoid afternoon heat
Move desks away from windows (solar exposure)
Breaks and cold drinks Resulted in 1.14 million ton
CO2 emission reduction
2/1/2014 74
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In Summary…
Occupant behaviour has a profound influence
on building performance
Occupants are not the excuse but the
solution to high-performance buildings
Comfort cannot be expressed with a single
metric – it is complex
Case studies and software tools are
invaluable for influencing design
Occupant behaviour should be considered
up-front in design.
Acknowledgements
Burak Gunay
PhD Candidate
Brent Huchuk
MASc Candidate
Austin Selvig
MASc Candidate Ryan Kuhne
MASc Candidate
Aly Abdelalim
PhD Candidate Sara Gilani
PhD Candidate
Laura Scrimgeour
Research Assistant
Isis Bennet
Research Assistant
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Two-day conference – 70 technical
presentations on wide variety of
building performance topics @ St.
Brigid’s Centre
Industry-conference reception @
Bridgehead Roastery
8 workshops @ Carleton
We are looking for a few more
partners
THANK YOU – QUESTIONS? Liam O’Brien – [email protected]