PASSIVE VENTILATION THE STRUCTURE CONSISTS OF A DOUBLE-SKIN FAÇADE THAT USES WIND AND SUN TO PROVIDE NATURAL VENTILATION 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 RADIANT 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.
PHILOGY LIBRARY, FREE UNIVERSITY FOSTER & PARTNERS
passive: operable fenestration promotes space ventillation allows for passive cooling strategies
• what is it? types: operable windows operable skylights louvers doors
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 quality provides simple, direct natural ventilation into a building provides natural air circulation serves as a physical and/or visual connection to the outdoors gives occupants the ability to control the amount of natural ventilation to the space secondary function - permits daylighting
• precedent: charles hostler student center Beirut, Lebanon
Architect: VJAA with the Lebanon based Samir Khairallah & Partners Transsolar, environmental consultants Hargreaves, 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, and a green field 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
Passive System: Solar Chimney
A solar chimney uses convection and solar radiation to increase the temperature inside 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 the difference 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 by using vents at lower levels, and this air is moved through the building and out the chimney. Su n ligh
t
Black painted solar chimney
Another way of bringing cold air into the building is through the use of a geothermal heat exchange system. Air is channeled underground before it is allowed to enter the building, 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.
LycĂŠe Charles de Gaulle Location: Damascus, Syria Architect: Ateliers Lion Environmental Engineer: Transsolar Built: 2008 This French school in Damascus was designed with a mission to embody sustainability through the use of low technology, passive ventilation systems. They achieved this through a combination of solar chimenys, small, micro-climate courtyards to draw cooler air from, and light, removable shading systems.
heat exchange Ventive passive design strategy
united kingdom passive heat exchange ventilation system
what is it
lowers heat requirements by preheating incoming air
Assembly
advantages
how it works
-no maintenance -no horizontal surfaces to collect dust -no moving parts -easy installation -no visual impact -95% heat recovery
Green and Blue Roof Systems “A roof design that is explicitly intended to store water, typically rainfall.” BENEFITS a blue roof is a non-vegetated system that detains stormwater, slowing or storing storm-water runoff by using various flow controls regulating, blocking, or storing water, which is temporarily stored or harvested for nonpotable uses on-site or discharged directly into sewer systems at a reduced flow 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 filling 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 benefits 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 roofing 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 reflect sunlight in the summer green and blue roofs reduce water overflow 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 roofing 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 flat roofing styles with wide gutters and watertight liners therefore only working on a limited number of roofing designs retrofitting existing roofs to meet the requirements for green and blue roofs is difficult and expensive, and voids any pre-existing roof warranties
Osborne Association Building by Hazen and Sawyer South Bronx NY FEATURES NY’s blue roof pilot project created to evaluate the potential of roof systems for mitigating sewer overflow, 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 overflow, “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
these systems are most effective in highly urbanized areas where less space is available for on-site stormwater detention
Passive Systems
Blue and Green Roof
Shannon Ferguson
passive material performance: living walls -
-
help to reduce local wind speeds help to reduce traffic 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 significantly increase infiltration 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, flowers, 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, saucershaped 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 Fernรกndez, 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
DEFINITIONS 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
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.
STRATEGY+EQUIPMENT 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.
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.
ADVANTAGES 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
DISADVANTAGES 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
Most helpful site: http://www.epa.gov/watersense/outdoor/rainwater_reuse.html
passive
+
active
strategy
Wa 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.
Passive Design Integrated Daylighting: A system that collects/ reflects sunlight though static, non-moving, and non tracking systems. Examples are windows, sliding glass doors, skylights, light tubes, and reflecting daylighting deeper into a space through the use of elements such as a light shelf
-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 ‘baffles’ are fitted underneath every monitor. This allows diffused natural light to be filtered into each space. -Interior courtyards use the same system to provide this natural diffused light into the administrative areas. -Each room is equipped with a daylight and occupancy censor to control the use of fluorescent light allowing them to turn on all to none of the fluorescent lamps in the room.
Durant Road School, Wake County, North Carolina, USA Architect: Innovative Design, Raleigh, North Carolina
-The orientation of the classroom corridors along the east-west maximizes potential passive solar gain in the winter. http://www.iisbe.org/system/files/Task23_CS_examples.pdf
PASSIVE: DAYLIGHTING STRATEGIES
Skylights_Difficult to control heat gain and glare, and can cause roof leaking if it is not sealed properly. Raise and curved or raised and pyramidal shaped skylights are most effective in capturing sunlight throughout the day.
Clerestories_Very effective when used on N & S sides, positioned as close to ceiling height as possible. N clerestory should be transparent and S should be translucent for most even daylight without glare.
Monitors_ Most effective if these face north and south with a sloped ceiling as shown to allow sunlight 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.
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.
Window with shading_Vertical blades in a horizontal overhang are most effective. Angled blades require less material in shade. Most effective when the shades extend past the extents of the window frame.
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: Subterranean Strengths: Takes advantage of temperature stability of soil,
Surface finish only needed on exposed faces
Weaknesses: Drainage, Seeping moisture, Daylighting
Earth House
http://www.dezeen.com/2010/06/10/earth-house-by-bcho-architects/
Great Glass House
http://www.fosterandpartners.com/projects/great-glass-house/
Underground House
http://www.2030architects.co.uk/#!Residential/c20x9
Passive: Thermal Mass for Radiation Description:
Material Property Needs:
Process:
The use of a large mass, such as concrete, brick, tile or rammed earth, to absorb and release energy throughout the day.
- High heat capacity - Moderate conductance - Moderate density - High emissivity - Ideally serves a secondary function - ei, structure - Mass must have direct exposure to the source of radiation
-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
Advantages: - Can be used to help maintain a comfortable temperature 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 properly - May cause opposite of the intended effect - Less effective in environments with moderate diurnal temperature differences - Doesn’t all the mass to help the space “coast” through the day
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 thermal mass can help prevent radiant and conductive losses to the exterior. (Might not want to use in a cooling climate)
Placing other materials on thermal mass prevents direct line of sight and, therefore, prevents radiant energy gain.
Passive System: Building Orientation Buildings 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.
South-facing rooms The 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 rooms East 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
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.
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.
West-facing rooms As 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 rooms North-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 areas In general, outdoor living areas should be south-facing so they receive the sun when they are in use. As discussed in location, orientation and layout, if the building is located towards the north of the site, this will provide a south-facing outdoor area.
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.
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.
Facts
Supplies 5% of power to California 13,000 turbines in the state Enough turbines to supply power to the entire city of San Fransisco 3.5 cents per kilowatt/hour to produce Wind Energy Two types of systems: Utility Scale or On-Site Production
Passive System
Wind Technology
Levels
Small <50 kW Mid 50 to 500 kW Large >50 kW
Outcome
Small 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.
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 3
Electricity from the turbine powers the home!
Example 4KW System â&#x20AC;&#x201C; Residential Installation Cost Average Electric Bill: $250/mo Projected Annual Bill Escalation: 5% Cost Per Watt: $6.50
Step 2
Electricity is then connected either directly to the building or to the utility grid.
Off Shore Potential
California coast classified as 6 and 7. Good wind resource areas exist near shore, but a narrow continental shelf results in minimal shallow-water opportunities Result Off Shore potential is not possible
- 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