130605 levitt thermal autonomy.ppt

Brendon LevittLoisos + Ubbelohde, Alameda, CaliforniaUniversity of California, BerkeleyCalifornia College of the Arts, San Francisco

M. Susan UbbelohdeLoisos + Ubbelohde, Alameda, CaliforniaUniversity of California, Berkeley

George LoisosLoisos + Ubbelohde, Alameda, California

Nathan BrownLoisos + Ubbelohde, Alameda, CaliforniaCalifornia College of the Arts, San Francisco

Thermal Autonomy as Metric and Design Process

AUTONOMOUS BUILDING

Boards, .............................. $8.03½ mostly shanty boards.Refuse shingles for roof and sides, ... 4.00Laths, ................................ 1.25Two second-hand windows with glass, ... 2.43One thousand old brick, ............... 4.00Two casks of lime, .................... 2.40 That was high.Hair, ................................. 0.31 More than I needed.Mantle-tree iron, ..................... 0.15Nails, ................................ 3.90Hinges and screws, .................... 0.14Latch, ................................ 0.10Chalk, ................................ 0.01Transportation, ....................... 1.40 I carried a good part

on my back.In all, ............................. $28.12½

I got out several cords of stumps in

plowing, which supplied me with fuel

for a long time... The dead and for the

most part unmerchantable wood behind my

house, and the driftwood from the pond,

have supplied the remainder of my

fuel."

FIRST YEAR’S HEATING BUDGET:

50% OF CONSTRUCTION COST

AUTONOMOUS BUILDING

“The next winter I used a small

cooking-stove for economy, since I

did not own the forest.”

THE MODERN BUILDING

Sketch by LeCorbusier, 1930

ENERGY USE AS METRIC

BASELINE OPTION 1+7.15%

OPTION 2-0.16%

OPTION 3-7.42%

Sketch by LeCorbusier, 1930

kWh/

m2

ENERGY USE AS METRIC

BASELINE OPTION 1+7.15%

OPTION 2-0.16%

OPTION 3-7.42%

Sketch by LeCorbusier, 1930

• does not show occupant comfort

• does not show daily patterns

• does not show seasonal patterns

• does not show when or if systems can be turned off

• does not consider free-running or mixed mode operation

• does not question comfort assumptions

• does not question scheduling assumptions

• does not question mechanical systems assumptions

• undervalues how the building envelope filters the environment

kWh/

m2

SHACK IN THE WOODS

Envelope Performance LOW

Energy Use NONE

Occupant Comfort LOW

BUSINESS AS USUAL

Envelope Performance LOW

Energy Use HIGH

Occupant Comfort MEDIUM

THERMALLY AUTONOMOUS BUILDING

Envelope Performance HIGH

Energy Use NONE

Occupant Comfort HIGH

HIGH PERFORMANCE BUILDING

Envelope Performance HIGH

Energy Use LOW

Occupant Comfort HIGH

Credit: Eric Kilby

THERMAL AUTONOMY AS METRIC

percent of a year that occupants feel thermally comfortable through passive means only

THERMAL AUTONOMY :: THE DASHBOARD

percent of a year that occupants feel thermally comfortable through passive means only

TA = 86%

THERMAL AUTONOMY :: THE DASHBOARD

• weighted degree hours

• number of occupied hours

• percent of occupied hours

• histogram of annual distributions

• diurnal / seasonal patterns

TA = 86%

THERMAL AUTONOMY :: THE DASHBOARD

• weighted degree hours

• number of occupied hours

• percent of occupied hours

• histogram of annual distributions

• diurnal / seasonal patterns

TA = 86%

THERMAL AUTONOMY :: THE DASHBOARD

• weighted degree hours

• number of occupied hours

• percent of occupied hours

• histogram of annual distributions

• diurnal / seasonal patterns

TA = 86%

THERMAL AUTONOMY AS METRIC

lends itself to understanding:• envelope as environmental filter• Influence of internal loads• an intuitive focus on occupant comfort• assumptions of comfort, schedule, and systems selection• gentle failure• reduction of active systems• extended free-running periods

TA = 86%

... AS DECISION-MAKING TOOL

... AS DIAGNOSTIC TOOL

... AS DESIGN TOOL

FREMONT HIGH SCHOOL OAKLAND, CA

Credit: CAW Architects

... AS DECISION-MAKING TOOL:

“Do we need air conditioning?”

TA = 10%

NATURAL VENTILATION

TA = 81%

NATURAL VENTILATION

+ NIGHT FLUSH

TA = 65%

NATURAL VENTILATION

+ NIGHT FLUSH

+ OPERATING HOURS ONLY

12

3

6

9

12

457

8

1011

TA = 86%

TA = 86%

BASE SCHEME

OPTIMIZED SCHEMETA = 86%

TA = 10%

“Do we need air conditioning?”

BASE SCHEME

OPTIMIZED SCHEMETA = 86%

TA = 10%

YES!!!!

“Do we need air conditioning?”

maybe not

PIER 27 FERRY TERMINALSan Francisco, CA

Credit: America's Cup Event Authority

... AS DESIGN TOOL

“What is the role of shade?”

THERMAL AUTONOMY:

3%

THERMAL AUTONOMY:

13%

THERMAL AUTONOMY:

3%

THERMAL AUTONOMY:

96%

THERMAL AUTONOMY:

3%

THERMAL AUTONOMY:

97%

THERMAL AUTONOMY:

3%

THERMAL AUTONOMY:

3%

PRIVATE RESIDENCESonoma, CA

Credit: Turnbull Griffin Haesloop

... AS PATTERN-RECOGNITION TOOL

“When is it too hot?”

INITIAL DESIGNTA = 57%

BETTER GLASSTA = 59%

UNINSULATED SLABTA = 56%

AIR MOVEMENTTA = 68%

VERY HOT

VERY COLD

Thermal Autonomy: 12%SHACK IN THE WOODS

Thermal Energy Use: 315 kWh/m2BUSINESS AS USUAL

Thermal Autonomy: 12%THERMALLY AUTONOMOUS BUILDING

Thermal Energy Use: 82 kWh/m2HIGH-PERFORMANCE BUILDING

FUTURE RESEARCH

• Area- vs. occupancy-weighting in multi-zone buildilngs

• Benchmarking for different climates, building types, thermal comfort standards

• Benchmarking relative to Energy Use Intensity

• Tool for Mixed Mode operation scheduling

BRENDON LEVITT[brendon@coolshadow.com]

Loisos + Ubbelohde, Alameda, California

University of California, Berkeley

California College of the Arts, San Francisco