What is
Sustainable
Design?
Part Two:
Climate Related Issues
IslandWood, Seattle, Washington
Presentation Summary
In this presentation, we will discuss:
• Climate issues
• The Importance of the geographic region
• Climate Zones of North America
• Climate Zones of Canada
• The 4 primary bioclimatic building types
• Comfort Zone
• Microclimate
Presentation Credits
• This presentation was prepared by Terri Meyer
Boake, BES, BArch, MArch, LEED AP
• Associate Director School of Architecture
University of Waterloo
• Past President of the Society of Building
Science Educators
Buildings and Climate
• Climate varies around the globe and indigenous architecture used to
respond to climate
• 20th century buildings became exclusively dependent on mechanical
systems to heat and cool buildings
• International Style Architecture, characterized by sealed buildings, tried to
create an architectural style that ignored climate
• This has resulted in a proliferation of architecture that does not properly
respond to its climate
• Such buildings now account for between 40% and 70% of energy use in
North America – and this cannot be sustained given Climate Change (GHG)
and fossil fuel shortages
• This lesson will examine how to reconnect issues of local climate and
building design
Weather and Climate:
The weather of the world
varies by location as relates
to the distance from the
equator and as influenced
by aspects of geography
such as the trade winds,
adjacency to bodies of
water, elevation, etc.
The earth’s atmosphere
helps to moderate the
climate to prevent radical
shifts in temperature from
season to season and day
to night.
The Sun
The impact of the sun on
our buildings is a direct
result of our distance
from the equator.
This affects amounts of
solar radiation as well as
solar geometry.
Environmental Moderator:
A building’s primary function is to
provide shelter from the
elements, as a function of
CLIMATE.
To function as a moderator of the
environment and to satisfy all
other requirements, a building
envelope must provide control of:
1. heat flow
2. air flow
3. movement of water as vapour
and as liquid
4. solar and other radiation
Urban Ecology Centre, Milwaukee
Building envelopes are like
balloons…
Rose Planetarium, NYC
Modern building envelopes are like balloons… very thin but their
performance is therefore even more critical!
Technique vs. Technology
Old stone
buildings relied
on their
massive nature
to withstand
the weather.
New buildings
are comprised
of thinner
layers, that are
individually less
able to
withstand the
elements.
TRADITIONAL METHODS
BUILDING SCIENCE
These buildings also have “thin skins”. But
nowadays, people expect an awful lot MORE
PERFORMANCE from their buildings – as
technological symbols and cultural icons.
Shelter is just not enough.
Channel 4 News, London, Richard Rogers
Greater London Authority, Norman Foster
High Performance Buildings
Bio-climatic Design:
Design must first acknowledge regional, local and microclimate
impacts on the building and site.
COLD
TEMPERATE
HOT-ARID
HOT-HUMID
Image: 1963 “Design With Climate”, Victor Olgyay.
Different climates around the world
Image source: Design with Climate. Victor Olgyay, 1963.
The climate regions of Canada
Even within Canada,
there exist variations
in climate, enough to
require very different
envelope design
practices and
regulations. This
mostly concerns
insulation and water
penetration, as well
as humidity concerns.
Heating and Cooling Degree Days
This map shows the annual sum of heating degree days (an indicator of building
heating needs). Data for period 1941 to 1970. Determine if the climate is heating or
cooling dominated …this will set out your primary strategy.
Cold Climate
Cathedrals
Buttressing systems in stone allowed
for the enlargement of glazing
systems that were once hindered by
the limitations of the wall – giving
more light and heat to the interior of
cold, draughty cathedrals.
Notre Dame Cathedral, Paris
Hot Climate
Cathedrals:
Gothic cathedrals in hot climates did
not use buttress systems to increase
their window areas as they did not
want more windows to allow heat
into the buildings.
Santa Maria del Fiore, Florence
Traditional hot climate design:
In hot dry (arid)
climates
windows are kept
to a minimum to
prevent the sun
from entering
the building.
Bright stucco
finishes are used
to reflect light
and keep the
environment
bright.
Courtyard buildings:
Courtyards are used in hot arid climates and
work well because sun can warm these spaces
in cooler months. Courtyards do NOT work well
in cold climates because of low winter sun
angles.
…designing for
a cold climate…
Designing for a cold climate
requires a completely
different approach to design
and respect for the weather.
Buildings must be designed
with an environmental
barrier.
Buildings must be more
concerned with their
“heating season” than their
“cooling season”
Traditional cold climate design:
At this time heating costs were low,
nobody was concerned about CO2
emissions and global warming, so
fossil fuels were burned.
Traditional cold climate design in
Canada took to task the shedding of
snow from roofs and used minimal
windows in the walls to try to keep
heat inside the building.
The Comfort Zone
The Comfort Zone refers to the range of temperature conditions of air movement,
humidity and exposure to direct sunlight, under which a moderately clothed human
feels “comfortable”.
This will be different for Indoor versus Outdoor conditions.
These will be different for different CLIMATE types.
This will be different for different cultures combined with climate conditions - what are
people used to??
As Architects we use our buildings
to not only create comfortable
indoor environments, but also
pleasing and useful spaces outside
of our buildings.
There exists a RANGE of comfort
that we need to design within.
REDUCING OPERATING ENERGY
Designing to the Comfort Zone vs. Comfort Point:
This famous
illustration is
taken from
“Design with
Climate”, by Victor
Olgyay, published
in 1963.
This is the finite
point of expected
comfort for 100%
mechanical heating
and cooling.
To achieve CN, we
must work within the
broader area AND
DECREASE the
“line” to 18C – point
of calculation of
heating degree days.
Passive Bio-climatic Design:
Reassessing the Comfort Zone
Comfort expectations may have
to be reassessed to allow for the
wider “zone” that is characteristic
of buildings that are not
exclusively controlled via
mechanical systems.
Creation of new “buffer spaces”
to make a hierarchy of comfort
levels within buildings.
Require higher occupant
involvement to adjust the
building to modify the
temperature and air flow.
Computer Science Building, York University, Toronto
Microclimate
When we design WITH the specific
local environmental characteristics
in mind, we start to manipulate the
relationship between the climate,
the site and the building to create a
local environment or
MICROCLIMATE around the
building.
This “mini climate” that is created
around the building can decrease
the apparent severity of the climate
(and hence the work the building
must do to make for a comfortable
interior AND exterior environment
around the building) OR, if badly
handled, can increase the severity
of the local climate.
St. Thomas University, Houston
…this does not belong here…
Basic understanding of the 4 climate design zones tells us that certain building types
obviously do not belong in certain places...
…but there are more aspects to consider...
Source: Leonard Bachman, University of Houston
The Multivariate Condition
Site Bio-Configuration
Whatever the FOUND condition of
the site upon which we are to
consider building has a climate
that is not only dependent upon
the general climate of the
REGION, but also, the specific
climate of the site as affected by:
•the surface or surfaces that cover
the ground
•available tree cover, size, height,
biodiversity, species, etc.
•nearness to water
•amount of paving adjacent
•height of adjacent buildings
Institute of Contemporary Art, Boston
Original condition
Hot Arid Site
Hot Humid Site
The building might be the same but the site/climate/microclimate conditions will
drastically impact the success of the comfort experienced by the occupants.
Temperate Site
Cold Site
Urban Heat Island Effect
Downtown Houston
Whether you are sited in a city or suburban space makes a difference. Access
to green space can keep the building cool. The “urban heat island effect” is
caused by too much building, hot roofs, pavement, (aka thermal mass) and
not enough greenery in cities. Tree cover is also important to keep the sun
off of paved areas. The microclimate in urban centres can be very different
from more natural sites.
Buildings and Climate
HOT-HUMID
HOT-ARID
TEMPERATE
COLD
Buildings MUST be designed to fit in with their CLIMATE. Different climate zones
demand different architectural responses in order to function properly and be
energy and environmentally efficient.
Bio-climatic Design: COLD
Where winter is the dominant season and concerns for
conserving heat predominate all other concerns.
Heating degree days greatly exceed cooling degree
days.
RULES:
- First INSULATE
- exceed CODE requirements (DOUBLE??)
- minimize infiltration (build tight to reduce air changes)
- Then INSOLATE and fenestrate for DIRECT GAIN
- ORIENT AND SITE THE BUILDING PROPERLY FOR THE
SUN
- maximize south facing windows for easier control
- apply THERMAL MASS inside the building envelope to
store the FREE SOLAR HEAT
- create a sheltered MICROCLIMATE to make it LESS cold
YMCA Environmental Learning Centre,
Paradise Lake, Ontario
Bio-climatic Design: HOT-ARID
Where very high summer temperatures with great
fluctuation predominate with dry conditions
throughout the year. Cooling degrees days greatly
exceed heating degree days.
RULES:
- Solar avoidance : keep DIRECT SOLAR GAIN out of
the building
- avoid daytime ventilation
- promote nighttime flushing with cool evening air
- achieve daylighting by reflectance and use of LIGHT
Traditional House in Egypt
non-heat absorbing colours
- create a cooler MICROCLIMATE by using light /
lightweight materials
- respect the DIURNAL CYCLE
- use heavy mass for walls and DO NOT INSULATE
Bio-climatic Design: HOT-HUMID
Where warm to hot stable conditions predominate
with high humidity throughout the year. Cooling
degrees days greatly exceed heating degree days.
RULES:
- SOLAR AVOIDANCE : large roofs with overhangs that
shade walls and to allow windows open at all times
- PROMOTE VENTILATION
- USE LIGHTWEIGHT MATERIALS that do not hold heat
and that will not promote condensation and
dampness (mold/mildew)
- eliminate basements and concrete
- use STACK EFFECT to ventilate through high spaces
- use of COURTYARDS and semi-enclosed outside
spaces
- use WATER FEATURES for cooling
House in Seaside, Florida
Bio-climatic Design: TEMPERATE
The summers are hot and humid, and the winters
are cold. In much of the region the topography is
generally flat, allowing cold winter winds to come
in form the northwest and cool summer breezes
to flow in from the southwest. The four seasons
are almost equally long.
RULES:
- BALANCE strategies between COLD and HOTHUMID
- maximize flexibility in order to be able to modify
the envelope for varying climatic conditions
- understand the natural benefits of SOLAR
ANGLES that shade during the warm months and
allow for heating during the cool months
IslandWood Residence, Seattle, WA
Presentation Summary
In this presentation, we discussed:
• Climate issues
• The Importance of the geographic region
• Climate Zones of North America
• Climate Zones of Canada
• The 4 primary bioclimatic building types
• Microclimate
• Comfort Zone