Transcript How Green is My Building? Resource systems in buildings

How Green is My Building?
Resource systems in buildings
Resources & people move into buildings,
“do things” in there, and leave buildings
People & animals
Energy & light
People & animals
Food & water
Waste heat
Furniture & stuff
Garbage & sewage
Clothing & fabrics
Discarded stuff
Air & moisture
Emissions
Pollutants
Toxic wastes
Chemicals &
materials
Cooking, eating, drinking,
sleeping, washing, watching,
reading, talking, creating,
destroying, playing, singing
In conducting a “green audit” of a building, the
following need to be considered
• Resources & materials in the building
structure and moving through the building
• Lifecycle costs of those materials (e.g., new,
recycled, energy inputs) & activities?
• Broader ecological impacts of acquiring those
materials (e.g., types of wood, stone)?
• Broader ecological impacts of processing,
using, disposing of materials (e.g., energ,
emissions, wastes, etc.)
And we need to pay attention to the “wild
card” in all of this:
How people behave in and interact with buildings
In next week’s “lab,” you will be asked to conduct a resource audit
of one of the PICA buildings—a relatively simple case
A building can be understood as organized
around an “ecological system”
To determine its “greeness,” we need to disaggregate its sub-systems &
measure flows into and out of the building
We also need to study how external inputs impinge on
its structure, its interior and its occupants
For example, does afternoon
sunlight come through the
windows unobstructed,
thereby making rooms too
warm for comfort?
What do the occupants do in
response? Draw shades or
blinds? Open windows? Turn
up the air conditioning?
We start with the “building
envelope”
• Of what is it made? Wood? Stucco?
Siding?
• What is the area of its external
components? Roof? Windows? Doors?
Walls?
•What kinds of “driving potentials”
impact on the envelope? Sunlight?
Wind? Shading? Toxins?
• Is there insulation in the walls and
attic? What kind? How old?
We need to measure or estimate resource flows
through the envelope
The first thing to do is to locate the three meters-electricity, gas, water—and to measure usage over time.
You may want to turn things on and off. It is also useful to
have a bucket and watch to measure water flows from
spigots and faucets.
Next, you need to estimate heat flows through
the building envelope
A common way to assess conduction, in particular, is to calculate
the “R-value” of the building’s envelope. R-value is a measure of
“resistivity.
R = inside-outside temp diff. x area x time
heat loss
Wood: 1” has R-value of 1.56; Stucco: 0.20/inch; Brick: 0.20/in.
(Wood studs can act as conduits for heat transfer; metal is worse)
It is also important to try to measure solar gain
and air flows through the envelope
We are in Zone 5, which is fairly
temperate; recommended Rvalues are relatively low.
We can calculate the annual
heating “need” using the concept
of “degree days.” This is 65ºF
minus the outside temperature
for “heating degree days” of
the outside temperature minus
65ºF for “cooling degree days”
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The next step is to measure energy use and
heat gains from various internal components
Users & sources need to be identified and
usage estimated or calculated—this includes
appliances and secondary components
Lighting can also be a major energy user:
there are specific design lighting
standards for different spaces
Count the lightbulbs,
determine their
wattage, estimate
their daily usage
For energy use, all of these inputs need to be calculated and aggregated.
Next, we turn to water inputs and sewage outputs—these are roughly equal.
•Try to measure water use over a typical daytime hour, using the meter
•Measure water flows from spigots & faucets, using a bucket and watch
•Observe occupant usage during a typical daytime hour
Another important consideration is
moisture in the building, which can
result in unwanted condensation, mold
and mildew. Other pollutants include
radon, chemicals, outgassing from
plastics and carpets, etc.
Other inflows and outflows include:
• Movement of foods and liquids into the building and
garbage and wastes out of the building
• Office and other paper supplies
• Furniture and office equipment
• Clothing, fabrics, wall coverings, blinds
• Ideally, we would estimate their resource impacts and
try to calculate life-cycle costs for the building, its
components, and the various flows through the
building
LEED: Leadership in Energy &
Environmental Design
• Green Building Rating System developed by the U.S. Green
Building Council
• Allocates points for building design features (NOT operation
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Sustainable sites (14 points)
Water efficiency (5 points)
Energy & atmosphere (17 points)
Indoor environmental quality (15 points)
Innovation and design process (5 points)
• Buildings are then certified according to total number of points
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Certified - 26-32 points
Silver - 33-38 points
Gold - 39-51 points
Platinum - 52-69 points
Improvements can be made to existing
buildings
• Replace existing heating and cooling systems with
more efficient units
• Replace appliances with lower-energy models
• Install flow restrictors on faucets & spigots; install a
graywater system for outside watering
• Install insulation in attic (first) and walls (second),
and new windows and frames (as appropriate)
• Install solar water heating or on-demand heater, as
well as solar PVs to supply some level of electricity
• Add Trombe walls, clerestories and light pipes
• The question of cost and benefit remains, and the
declining cost of oil raises major economic questions