The Need For Systems Integration with Passive Strategies John Nelson, Architectural Energy Corporation David Banks, Cermak Peterka Petersen Rob Slowinski,

The Need For Systems Integration with Passive Strategies

John Nelson, Architectural Energy CorporationDavid Banks, Cermak Peterka Petersen

Rob Slowinski , Architectural Energy Corporation

Learning Objectives

• Review the drivers for passive architectural strategies, and the status of the industry in regards to adoption of their principles.

• Review the principles of natural ventilation and passive conditioning.

• Present examples of how projects overcame barriers through integration.

Images by Transsolar

State of the Industry & Planet: Trends

Muir Glacier, Alaska 1941 Photo by W.O. Field Muir Glacier, Alaska 2004 Photo by B.F. Molina

Graph by Rocky Mountain Institute

Graph by American Center for Progress

Graph by 2030 ChallengeData: Energy Information Administration

State of the Industry & Planet: Trends

Paradigms• Overlook architecture’s

affect on energy use• Monolithic Temperatures• Trade offs between peak

and efficient normal operation

Photos by: James Balog

Turning Momentum

• Proof of concept• Loads of research available• 2030 Challenge

commitments• Restlessness in

professionals

Photo courtesy of NREL’s Photo Exchange

Passive Strategies: Potential & Adoption

Total US Office Building Energy Use

Source: Energy Information Administration

• Daylight• Natural Ventilation• Passive Conditioning

Heating 25%

Cooling 9%

Lighting 29%

Equipment 26%

Ventilation 5%

Other 16%

Graph courtesy of Wikipedia

Thermal Inertia

• ‘during spring and autumn, lightweight buildings may require both heating and cooling over the diurnal cycle, whereas the thermally heavy buildings can maintain comfortable internal conditions without either supplementary heating or cooling.’

– BRE Digest 454• ‘Most modern buildings are structurally heavy but thermally light.

Widespread use of carpets, floor voids, false ceilings and plasterboard wall liners, all of which effectively insulate the structure from the environment’

– BRE Digest 454• ‘Thermal storage techniques absorb heat during peak periods of

excess gain and store it until it can be discharged later.’ – CIBSE Mixed Mode Ventilation AM:13

Photo By Tom Arban

Approach of Thermal Balance

Images courtesy of Terrapin Bright Green & Rocky Mountain Magazine

Quality

Photo courtesy of World Architecture Festival

Chart by Rocky Mountain Institute

Integrated Design“Integrated design is both a process and a result”

-Michael Holtz, FAIA

Chart by Rocky Mountain Institute

Climate & Location Analysis

Image courtesy of World Architecture Festival

Testing Concepts: Modeling

• Test our strategies• Become informed to

enhance / optimize design

• Optimize glazing amount = upfront and operational savings

Push boundaries on paper first:“Only a fool views success as never having been wrong”

-Jason McLennan (Living Building Challenge creator)

Modeling by Zack Rogers

Eras & Intentions

Manitoba Hydro Headquarters, Photo by Eduard Hueber

NATURAL VENTILATION & ADAPTIVE COMFORT

Air flow from:• stack effect• winds

Related issues:• thermal mass• heat loads• expectations

How to Ventilate Naturally

Stack EffectDriven by • temperature difference• Height of column of air• gravity

WindDriven by • Wind speed• Pressure

fluctuations due to building shape and surroundings

Wind speed will overwhelm stack effect at 3-10 mph. This is most of the time.

Seasonal and diurnal wind directions

Time of day

Win

d d

ire

cti

on

Air Flow Simulations

• Nodal model/ Building Energy Sim• For the whole building• “Coupled” important if stack effect is a big part

• Computational Fluid Dynamics (CFD)• For details of a single room or building segment• Simulates a specific situation

• Boundary Layer Wind Tunnel• For outside the building• Does not predict indoor flows

Boundary-Layer Wind Tunnels

A boundary layer wind tunnel recreates the turbulent winds of the lower atmosphere in a controlled environment.

ASHRAE adaptive comfort model

Air Movement

Personal ControlOur primary objective in this project was to examine the differences between individuals with relatively high and low degrees of control in the same naturally-ventilated building… While these two groups were experiencing similar physical conditions that influenced their heat balance, we found significant differences in their subjective response … While behavioral mechanisms are certainlysignificant in allowing people to adjust their personal comfort, psychological dimensions are also relevant to the degree of thermal comfort experienced.

This emphasizes the importance of not just designing a building with a high degree of adaptive opportunity, but ensuring that all occupants have direct and easy access to those various means to control their own environment.

Operable windows were, by far, the most used control. Blinds were used about half as often as windows, and ceiling fans or desk fans were used even less.

Gail Brager, ASHRAE Transactions

Survey findings: green vs. conventional

LEED/green (n=20); rest of database (n =161)

Air quality satisfaction, by building type

INTEGRATED RESULTS: LEADING THE WAY

Integrated Results:Stanford’s Y2E2, CA

• Stack effect:4 central atria

• BAS and occupant-controlled natural ventilation

• Exposed slabs integrate with architecture

• Chilled beams well-suited for natural ventilation when systems are active

Photo by: John Nelson

Image courtesy news.stanford.edu

Integrated Results:Stanford’s Y2E2, CA

Photos by: John Nelson

Integrated Results:NREL RSF, CO

• Massing for daylight = massing for natural ventilation

• Exposed mass for passive integrated with radiant

• Radiant can use low grade heating & cooling (eg: solar thermal)

Photos courtesy of NREL’s photo exchange

Integrated Results:NREL RSF, CO

• UFAD: Office flexibility, efficient ventilation, and exposed ceilings all with one strategy

• Indirect/direct couples well with ‘open’ buildings

• Transpired solar collectors

Upper photo: John Nelson / Lower photo courtesy of NREL’s photo exchange

Integrated Results:Tulane University, New Orleans, LA• New Orleans historic

architecture with layers of shading

• Thermal zoning: designed for ‘open operation’ fall and spring

• Daylight with good shading = low solar heat gain & low internal loads

Photo courtesy of Archilovers.com

Integrated Results:Muechener Tor, Munich Germany

• 2 central stacks, 20 stories high

• No mechanical ventilation• Supply air conditioned

with geothermal ‘air to earth’ register

• Free cooling of exposed slabs and night flush is supplemented with radiant cooling from ground water

Photo courtesy of Wikipedia

Integrated Results:Unilever Headquarters, Hamburg, Germany

• Area of high winds -> double façade/hybrid ventilation

• Concerns about exhaust from harbor

• Exposed mass/radiant heating

• Large atria is ‘building’s lungs’

Photo courtesy of World Architecture Festival

Questions?

John Nelson, Architectural Energy CorporationDavid Banks, Cermak Peterka Petersen

Rob Slowinski , Architectural Energy Corporation