PASSIVE VENTILATION

PHILOGY LIBRARY, FREE UNIVERSITYFOSTER & PARTNERS

THE STRUCTURE CONSISTS OF A DOUBLE-SKIN FAÇADE THAT USES WIND AND SUN TO PROVIDE NATURAL VEN-TILATION FOR MOST OF THE YEAR. THIS BUILDING HAS AN OUTER LAYER OF WINDOWS AND ALUMINUM PANELS, AND AN INNER LAYER OF FIBERGLASS FABRIC. IN WINTER, WARM AIR BETWEEN THE LAYERS RISES TO THE TOP, THEN IS DRAWN DOWN THROUGH THE BUILDING TO PROVIDE HEAT. THE SPACE BETWEEN THE INNER AND OUTER SKIN SERVES AS AN AIR CHAMBER FOR NATURAL VENTILATION THE BUILDING.

VENTILATION DUCTS INTEGRATED INTO THE RAISED FLOOR OF THE BUILDING, A CONCRETE CORE WITH RADI-ANT HEATING AND COOLING SYSTEMS IMPROVE OCCUPANT COMFORT. THE BASEMENT IS DOUBLE-WALLED AND IS USED TO PREHEAT THE VENTILATION AIR PREREFRIGERAR THROUGH CONTACT WITH THE GROUND.

passive: operable fenestrationpromotes space ventillationallows for passive cooling strategies

•what is it?types:operable windowsoperable skylightslouversdoors

how they work:manual operation (differs based on style)some operate via weather sensors - either moisture or temperature controlled

what they do:improves indoor air qualityprovides simple, direct natural ventilation into a buildingprovides natural air circulationserves as a physical and/or visual connection to the outdoorsgives occupants the ability to control the amount of natural ventilation to the spacesecondary function - permits daylighting

•precedent: charles hostler student centerBeirut, Lebanon

Architect: VJAAwith the Lebanon based Samir Khairallah & PartnersTranssolar, environmental consultantsHargreaves, landscape designers

Project Completion Date: 2008

Client: American University of Beirut

the building program: sports facilities including an indoor swimming pool, a multi-use gymnasium, basketball courts, indoor football and handball courts, squash courts, a refurbished track, andagreenfield

accommodate a 280-seat auditorium, a 250-seat amphitheater, a cafe, student activity rooms, an internet room, and an underground parking area for around 200 cars

passive strategies: Oriented to direct sea breeze through the building creating temperate microclimates around the center

traditional shading technique of self-shading as buildings cast shadows on each other and on outdoor spaces

natural ventilation through large operable openings on the north and south facades

Operable skylights were also used over the pool and gymnasium to enhance ventilation through stack effect

additional ways of utilization: operable skylights/fenestration for passive cooling by promoting cross ventilation

Sunlight Black painted solar chimney

Passive System: Solar Chimney

Lycée Charles de GaulleLocation: Damascus, SyriaArchitect: Ateliers LionEnvironmental Engineer: TranssolarBuilt: 2008This French school in Damascus was designed with a missionto embody sustainability through the use of low technology,passive ventilation systems. They achieved this through acombination of solar chimenys, small, micro-climate courtyardsto draw cooler air from, and light, removable shading systems.

A solar chimney uses convection and solar radiation to increase the temperatureinside the chimney to utilize the stack effect to move air through a building. It is a passive system which changes the indoor-to-outdoor air density resulting from thedifference of temperature within the spaces.The chimney will generally have a heat absorbing material or color (typically black)in order to maximize the solar heat gain. Cold air is brought into the building byusing vents at lower levels, and this air is moved through the building and out thechimney.

Another way of bringing cold air into the building is throughthe use of a geothermal heat exchange system. Air ischanneled underground before it is allowed to enter thebuilding, effectively cooling the air before it is circulated.

Benefits of solar chimneys:-Improved ventilation on hot, still days.-Improved air flow control.-Reduced dependence on active ventilation systems.-Improved air quality.-Improved thermal comfort.-Reduced reliance on wind driven ventilation.

heat exchange Ventive passive design strategy united kingdom

what is it

passive heat exchange ventilation system

lowers heat requirements by preheating incoming air

how it works

Assembly

advantages -no maintenance-no horizontal surfaces to collect dust-no moving parts-easy installation-no visual impact-95% heat recovery

Passive SystemsBlue and Green Roof Shannon FergusonShannon Ferguson

Osborne Association Building by Hazen and Sawyer South Bronx NY

Green and Blue Roof Systems“A roof design that is explicitly intended to store water, typically rainfall.”

FEATURES

NY’s blue roof pilot project created to evaluate the potential of roof systems for mitigating sewer overfl ow, in-turn utilization of blue and green roofs could save NYC $2.4 billion over 20 years

created a state-of-the-art system that uses plants and water retention trays to reduce stormwater overfl ow, “blue” portions of the rooftop utilize trays and small rock beds to hold rainwater and slow entry of water into the sewer system while reducing erosion potential

easing pressure on NY’s sewer system saves billions of dollars that would otherwise be spent on detention systems

plants and soil make up the remainder of the “green” system which absorbs and repurposes additional water

system promotes a 32% decrease in stormwater runoff and manages over 100,000 gallons of stormwater a year

greenery on the roof reduces heating and cooling costs

“green” roof portion improves air quality provides a thriving habitat for the association’s urban beekeeping business

a combination blue and green roof was less expensive to install than a green roof alone and provides a lighter, more cost-effective alternative for NY’s older buildings that otherwise might not be able to withstand the weight of a traditional green roof

the use of a tray system distributes the additional roof loading in the locations that have the greatest load-bearing capacity, trays can be moved to accommodate repairs to the roof and individual trays can be replaced without replacing of the overall system

blue roofs generally require less maintenance making the total system less maintenance intensive

the life of the rooftop system is expected to outlast the life of the roof membrane, in excess of 30 years

monitoring equipment on the roof measures the difference between the precipitation rate and the rate of runoff entering the sewer system, the data of which will inform the design of future rooftop stormwater management projects in the city

BENEFITS

a blue roof is a non-vegetated system that detains stormwater, slowing or storing storm-water runoff by using various fl ow controls regulating, blocking, or storing water, which is temporarily stored or harvested for non-potable uses on-site or discharged directly into sewer systems at a reduced fl ow rate

blue roofs help to attain city’s Low Impact Development stormwater standards where the detained water can be used for irrigation, cleaning sidewalks or reducing potable water use by fi lling or toilets

blue roofs can be used to integrate rooftop recreational activities, used to irrigate a green roof, cool the roof of a building on hot days reducing the HVAC load placed on mechanical cooling equipment

blue roofs are less costly than green roofs so when systems are combined it reduces the costs of installation and maintenance

blue roofs provide an option when a roof cannot handle the additional weight of a green roof, providing equivalent stormwater detention in comparison to a green roof at a fraction of the cost

green roofs provide the benefi ts improving air quality (by absorbing carbon dioxide and airborne pollutants), rooftop cooling (lowering a facility’s operating costs), creating natural habitats, and increasing quality-of-life for residents and offer an opportunity for biodiversity and food production

cities often provide a “Green Roof Tax Abatement” from property taxes promoting the use of green and blue roofi ng systems, and enhance property value

green and blue roofs offer an insulating layer on top of a roof that trap energy in the winter and refl ect sunlight in the summer

green and blue roofs reduce water overfl ow by 40% promoting and revitalizing the health of surrounding waterways

membranes for blue and green roofs are meant to hold water for a prolonged period of time (24-48 hours), (rendering the use of traditional roof membranes unsuitable), requiring an expensive roofi ng system designed to hold water for extended periods of time (costs range from $1-4/s.f. for a blue roof and $18-25/s.f. for a green roof)

LIMITATIONS

blue roofs work best on long and fl at roofi ng styles with wide gutters and watertight liners therefore only working on a limited number of roofi ng designs

retrofi tting existing roofs to meet the requirements for green and blue roofs is diffi cult and expensive, and voids any pre-existing roof warranties

these systems are most effective in highly urbanized areas where less space is available for on-site stormwater detention

passive material performance: living walls

- help to reduce local wind speeds- help to reduce tra�c noise- help to reduce localized temperature extremes (urban heat island) by shading and converting liquid water to water vapor (evapotranspiration) which cools the air.- help to improve air quality by reducing dust and particulates- help to reduce the amount of heat lost from a home.- help increase in biodiversity, along with aid for food and shelter for wildlife- signi�cantly increase in�ltration and storage of rainwater in their root systems- have a positive impact on both physical and mental health and wellbeing.- have seasonal variations in color, growth, �owers, and perfume which provide year round interest.- can provide local fruit and vegetation for the community.- have the potential to increase residential and commercial property values by between 7% and 15%- provide screening and /or barriers where fencing regulations may limit alternatives

Condensation Collection

Ancient Practices Historical Small-Scale Dew Ponds Air Wells

Small-scale drinking pools were created by natural or assisted condensation on plant stems.

Dew ponds are shallow, saucer-shaped pits constructed in southern England. They are often built in a hollow on the top of a hill. Lined with clay and straw, the ponds are believed to collect cooler air which allows water to condense.

Air wells can utilize three methods to promote condensation: high mass, radiative energy, or active technologies.

Modern Implementation Fog harvesting has been successfully implemented in coastal areas of Chile, Ecuador, Mexico, and Peru. Experimental projects have shown that it is possible to capture between 5.3 and 13.4 liters per square meter per day. Variables for successful implementation include frequency and density of fog, location, season, and type of collection system.

Nets stand perpendicular to the prevailing wind. After passing through the course woven mesh, drops of fog-water fall into collection troughs that carry the water to collection tanks.

An alternative version of the vertical nets are conical forms that funnel the fog into a constricted space. When compressed, water droplets collect and fall into a collection tank.

Precedent

Proposal: Coastal Fog Skyscraper Architects: Alberto Fernández, Susana Ortega Location: Huasco City, Chile

With 10,000 square meters of vertical surface, the tower would produce a minimum of 20,000 and a maximum of 100,000 liters per day. In this particular design, water would be routed to agricultural land that is suffering from severe drought.

Michael Reilly 10/14/2013

p a s s i v e + a c t i v e s t r a t e g y

W a t e r C o l l e c t i o n G r e y w a t e r R e u s e

W A L L A W O M B A G U E S T H O U S E Bruny Island, Tasmania, Australia | 1+2 Architecture | 2150 sq ft Waste from the house is managed through a black-water collection point and gray-water reclamation system. This system allows the release of gray water into trenches after passing through a series of treatment steps. The release of gray water can be used to encourage plant growth in the vicinity of the release area and is completely benign to the environment.

Two 2,600 gallon underground tanks store rainwater collected from corrugated and perforated roofs. Water is then pumped up into the house for various domestic uses, including the toilets and tub.

D E F I N I T I O N S Rainwater | water fallen as rain with little dissolved mineral matter Greywater | used water from sinks and showers, and not toilets Rainwater Collection | rainwater and condensation is collected from a roof and stored in a variety of ways or redirected using gravity or pumps to be reused Greywater Reuse | reuse of household water for on-site and non-drinking water uses, reducing amount of potable water used

S T R A T E G Y + E Q U I P M E N T The roof acts as a 1catchment surface for rain and condensation and drains water to gutter 2(initial conveyance). The gutter delivers the water through gravity to a 3downspout filter and then to a 4collection tank. The water is then pumped to water uses or to overflow and drain area. In a climate that rains seasonally or intermittently, you would only collect and store a small amount to be dispersed throughout the year in a large cistern, likely underground or in a crawl space with a pump and simple filtration system to keep the water free of debris and insects. This water can be used for irrigation and toilets.

A D V A N T A G E S Rainwater collection is simple, low-tech, and low-cost The end use is close to the source eliminating more costly distribution system Superior quality irrigation water The zero hardness of rainwater helps prevent scale on appliances and eliminates water softening process

D I S A D V A N T A G E S The potential for pollution and undesirable health effects if the greywater is not reused correctly Initial cost of a greywater system and plumbing requirements and ongoing maintenance

Roof surface is built from a low-profile corrugated metal, which is perforated at its edge to allow water to pass into the gutter below while minimizing the debris that collects in the gutter.

Most helpful site: http://www.epa.gov/watersense/outdoor/rainwater_reuse.html

Passive Design

Durant Road School, Wake County,North Carolina, USAArchitect: Innovative Design, Raleigh, North Carolina

-Roofs were used to day light the rooms using tilted north and south facing roof monitors. This allows for all spaces to have natural light.

-The classroom corridors are located along the east-west axis which allows for the maximum amount of daylight to enter through the roof monitors above each classroom.

-To prevent direct sunlight into the spaces, translucent cloth vertical ‘ba�es’ are �tted underneath every monitor. This allows di�used natural light to be �ltered into each space.

-Interior courtyards use the same system to provide this natural di�used light into the administrative areas.

-Each room is equipped with a daylight and occupancy censor to control the use of �uorescent light allowing them to turn on all to none of the �uorescent lamps in the room.

-The orientation of the classroom corridors along the east-west maximizes potential passive solar gain in the winter.

http://www.iisbe.org/system/�les/Task23_CS_exam-ples.pdf

Integrated Daylighting:

A system that collects/ re�ects sunlight though static, non-moving, and non tracking systems. Examples are windows, sliding glass doors, skylights, light tubes, and re�ecting daylighting deeper into a space through the use of elements such as a light shelf

PASSIVE: DAYLIGHTING STRATEGIES

Skylights_Difficult to control heat gain and glare, and can cause roof leaking if it is not sealed prop-erly. Raise and curved or raised and pyramidal shaped skylights are most effective in capturing sunlight throughout the day.

Sidelighting: View glass with overhang_Overhangs are not needed on N side, are effective on S side, and would need to be excessively deep in order to be effective on the E & W side to control glare.

Clerestories_Very effective when used on N & S sides, positioned as close to ceiling height as pos-sible. N clerestory should be transparent and S should be translucent for most even daylight with-out glare.

Window with shading_Vertical blades in a horizon-tal overhang are most effective. Angled blades require less material in shade. Most effective when the shades extend past the extents of the window frame.

Monitors_ Most effective if these face north and south with a sloped ceiling as shown to allow sun-light to be reflected into the space. N monitors do not require sun shading, S facing will require an overhang, ceiling louvers or translucent finish on the glazing.

Window w/ light shelf_Light shelf acts as a shade for view glass below and also bounces light off the shade to the ceiling and into the space. Interior light shelf can be more effective than an exterior shelf.

Thermal Mass:SubterraneanStrengths: Takes advantage of temperature stability of soil, Surface finish only needed on exposed faces

Weaknesses: Drainage, Seeping moisture, Daylighting

Earth Househttp://www.dezeen.com/2010/06/10/earth-house-by-bcho-architects/

Underground Househttp://www.2030architects.co.uk/#!Residential/c20x9

Great Glass Househttp://www.fosterandpartners.com/projects/great-glass-house/

Passive: Thermal Mass for Radiation

Description:The use of a large mass, such as concrete, brick, tile or rammed earth, to absorb and release energy through-out the day.

Advantages:- Can be used to help maintain a comfortable tem-perature in either a heating or a cooling climate - Southern exposure in heating, Northern exposure in cooling- Can absorb radiant energy from any source that emits heat - Sun, people, lights, mechanical equipment- Generally works in conjunction with conduction and convection heat transfer- Allows air temperature to be lower for comfort -Effect of Mean Radiant Temperature

Disadvantages:- Can have negative effect if not implemented proper-ly - May cause opposite of the intended effect- Less effective in environments with moderate diur-nal temperature differences - Doesn’t all the mass to help the space “coast” through the day

Material Property Needs:- High heat capacity- Moderate conductance- Moderate density- High emissivity- Ideally serves a secondary function - ei, structure- Mass must have direct exposure tothe source of radiation

Process:-Temperature of “objects” > Temperature of Mass - Radiant energy is transfered to the Mass - Energy is transfered to the center of mass through conduction-Temperature of “objects” <Temperature of Mass - Radiant energy is transfered to the “Objects” - Energy is transfered to the center of mass through conduction

Diagramming:Radiant energy is absorbed by thermal mass through direct line of site.

Radiant energy is emitted from thermal mass when Tobject < Tthermalmass for objects in direct line of site

Adding insulation under the ther-mal mass can help prevent radiant and conductive losses to the exterior. (Might not want to use in a cool-ing climate)

Placing other materials on thermal mass prevents direct line of sight and, therefore, prevents radiant energy gain.

Generally, orienting the building so that its shorter

axis aligns with prevailing winds will provide the most

wind ventilation, while orienting it perpendicular to

prevailing winds will provide the least passive ventilation.

Passive System: Building OrientationBuildings should usually be oriented east-west

rather than north-south. This orientation lets you

consistently harness daylight and control glare

along the long faces of the building. It also lets

you minimize glare from the rising or setting sun.

Orientation #1 is worst for daylighting, #3 is

good, and #2 is best.

To even out temperature swings at sunrise and sunset,

east sides may benefit from more window area for

direct solar heat gain, while west sides may benefit

from smaller window areas and high thermal mass

to absorb the heat and release it through the night.

Buildings do not have to face directly into the wind to

achieve good cross-ventilation. Internal spaces and

structural elements can be designed to channel air

through the building in different directions. In addition,

the prevailing wind directions listed by weather data may

not be the actual prevailing wind directions, depending on

local site obstructions, such as trees or other buildings.

Shade from trees and landforms can be avoided

by building higher on a site or by using skylights

or clerestory windows. Taller buildings will

increase the amount of shaded area on a site.

South-facing roomsThe main living spaces such as living, family and dining rooms should be north facing where possible.

• Good daylight most of the day

• Solar gain for most of the day throughout the year

• May require horizontal shading to prevent overheating in summer

• Good passive solar gain in winter

East-facing roomsEast facing rooms are most suited as kitchen and breakfast areas as they can benefit from early morning solar gain throughout the

year and will be cooler in the late afternoon when evening meal preparation takes place

• Good morning light

• Solar gain in the morning throughout the year to provide initial warming

• Will be cooler in the late afternoon.

• Bedrooms that face east will be cooler in the late afternoon and evening, making them more comfortable for summer sleeping.

• Early risers generally appreciate east sun in spaces they will use first thing in the morning such as breakfast bars

West-facing roomsAs west-facing rooms get low-angle, late afternoon sun, they usually require some shading to prevent overheating and excessive

glare, particularly during the summer.

• Good afternoon daylight

• Can overheat in the late afternoon for much of the year

• May require vertical shading to prevent excessive overheating and glare in the afternoon

• Provide good direct solar gain for thermal mass heating of living spaces in the evening

• Suitable as a living area in households where occupants are away from home during the day-time but at home in the evenings

• Not generally suitable as a kitchen as the heat from dinner preparation coincides with low-angled afternoon and evening sun,

potentially causing glare and overheating

North-facing roomsNorth-facing rooms are not suitable for habitable spaces.

• Lower levels of daylight during parts of the year

• Little or no heat gain

• Most suited for the location of the garage, laundry, bathroom, toilet, workroom and stairs, where people spend little time and/or

use infrequently

Outdoor living areasIn general, outdoor living areas should be south-facing so they receive the sun when they are in use. As discussed in location, orienta-

tion and layout, if the building is located towards the north of the site, this will provide a south-facing outdoor area.

Passive System Wind Technology

LevelsSmall

<50 kWMid

50 to 500 kWLarge

>50 kW

FactsSupplies 5% of power to California

13,000 turbines in the stateEnough turbines to supply power to the entire city of San Fransisco

3.5 cents per kilowatt/hour to produce Wind EnergyTwo types of systems: Utility Scale or On-Site Production

Step 1 Wind spins the blades. A shaft running through a transmission box increasing the speed. The shaft turns a generator to make electricity.

Step 2 Electricity is then connected either directly to the building or to the utility grid.

Step 3 Electricity from the turbine powers the home!

OutcomeSmall scale wind energy is a great option for homes,

small businesses, and farms in windy locations, such as along the coast. Wind energy can also be used when

it is not feasible to run power lines.

Off Shore PotentialCalifornia coast classified as 6 and 7.

Good wind resource areas exist near shore, but a narrow continental shelf results in minimal shallow-water opportunities

ResultOff Shore potential is not possible

Example

4KW System – Residential Installation Cost

Average Electric Bill: $250/moProjected Annual Bill Escalation: 5%

Cost Per Watt: $6.50

- Estimated System Cost: $26,000- Federal/State Tax Credit: $6,072

- State/Utility Rebate: $5,760- Net Cost: $14,168

- Cumulative Lifetime Savings (25 Years): $46,987- Investment Return: 13.3%

Savings of 46% on the total cost of your solar system through incentives

Source: NREL, CA Energy Commission