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

Food & water

Furniture & stuff

Clothing & fabrics

Air & moisture

Pollutants

Chemicals & materials

People & animals

Waste heat

Garbage & sewage

Discarded stuff

Emissions

Toxic wastes

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 R-values 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”

J F M A M J J A S O N D T

52

42

81

181

291

506

516

403

351

284

219

129

3056

0 0 0 0 7 13

34

24

25

10

0 0 113

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– 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– 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