passive solar, passive cooling and daylighting

Passive Solar, Passive Cooling and Daylighting

OBJECTIVES Learn about :

The history of Passive SolarEnergy efficient designEnergy end usesPassive Heating and Passive CoolingDaylightingRenewables

The History of Passive Solar

5th Century BC Greece

Community Planning employed passive solar design.

Diminished fuel sources brought design changes.

Passive Solar in Ancient Greece Aristotle noted, builders made sure to

shelter the north side of the house to keep out the cold winter winds.

And Socrates, who lived in a solar-heated house, observed, "In houses that look toward the south, the sun penetrates the portico in winter" which keeps the house heated in winter.

Cross section of a Roman heliocaminus. The term means "sun furnace."

Roman heliocaminus The Romans used the term to describe

their south-facing rooms. They became much hotter in winter than similarly oriented Greek homes because the Romans covered their window spaces with mica or glass while the Greeks did not.

Solar Greenhouses from Ancient Rome to 18th Century

Europe

Canvas covered the glass in the evenings to hold in heat.

With the fall of the Roman Empire, so too came the collapse of glass for centuries in either buildings or greenhouses.

19th Century Solar Remodel with attached greenhouse

American Solar Heritage:

Anastasi Indians

Pueblo Indians’ Sky CityContinuously inhabited since the 12th century

Southwest AdobeOrientation, control & thermal mass

Adobe = Thermal Mass

The colonial "salt box" house, typical of New England architecture of the 18th century.

Maximizes Southern Exposure

The solar-heated Rose Elementary School in Tucson Arizona. It obtained over 80% of its heat from solar energy for an entire decade, beginning in 1948.

Village Homes subdivision built in the late 1970s in Davis, California. The layout of the subdivision allowed every house to face the winter sun.

Today

Generation and use of energy (electric, gas, oil, coal) are major contributors to air pollution and

global climate change.

And pollution of our rivers…….

MOUNTAIN TOP REMOVAL

Improving energy efficiency and using renewable energy sources are effective ways to improve air quality and reduce the impacts of global warming

Energy efficiency is a cornerstone of any green building project.

Passive Solar

Passive solar buildings aim to maintain interior Thermal comfort.

Passive solar building design is one part of green building design, and does not include active systems such as Mechanical ventilation or Photovoltaics

.

Passive Solar Design

The 47-degree difference in the altitude of the sun at solar noon between winter and summer forms the basis of passive solar design.

Passive solar building design revolves around 5 main aspects;

Aperature: The set of windows and overhangs that determine how much sun enters the building.

Absorber: The material that the sun’s ray come into contact with.

Thermal Mass: The material that stores the sun’s thermal energy for re-release after sundown.

Distribution: The means by which the thermal energy is released to the living/working spaces.

Control: The techniques used to control the collection and distribution of the sun's thermal energy.

Design Aspects:

Passive Solar Design Themes: Direct Gain: Sunlight shines into and

warms the living space. Indirect Gain: Sunlight warms thermal

storage, which then warms the living space.

Isolated Gain: Sunlight warms another room (sunroom) and convection brings the warmed air into the living space.

Passive Solar Heat Passive solar design can reduce heating

temperatures by 30-50% Windows need to be incorporated within

30 degrees of due south

indirect gain systems   In the indirect gain, a storage mass

collects and stores heat directly from the sun and then transfers heat to the interior space. There are several indirect gain passive solar systems :

Indirect Gain Water Wall

Trombe Wall

Isolated Gain Space:

Sunroom

Passive Solar Design Aspects

PASSIVE COOLINGPlant deciduous trees for shade

Natural ventilation is a key cooling strategy

Install window overhangs and awnings

Deciduous Shade Trees Primarily shade windows and paved areas Keep trees an appropriate distance from the

house and utility lines

Deciduous shade trees offer the best solution for keeping out low-angle sunlight from west and south windows in summer.

Shade trees can reduce summer air-conditioning costs by 25 – 40%.

Trees can create a microclimate that is up to 15 degrees cooler

than the surrounding area.

Trees also clean the air, create habitat and play areas for children as well as add aesthetic beauty to the neighborhood.

Overhang and Awnings

Overhangs are important parts of passive solar heating and natural

cooling.

Awnings and Overhangs

Help keep the heat of the sun out during the summer.

Wood trellises

Arbors

Adjustable or demountable awnings made of fabric or metal

Allow heat to enter during the winter.

DAYLIGHTING

• What is Daylighting?• Energy Savings• Productivity, Health and Well Being

This?

Or This?

Clerestory Windows

Modeling with the Heliodon

Heliodon at PG&E Energy Center

Daylight modeling with Heliodon

Daylight after construction

Daylighting Saves Energy and Improves Productivity

Deck Mounted Skylight

Sun tracking systems

Skylights

Solar Tubes:Inexpensive, Easy to install …

And very effective

Daylighting on a large scale

REVIEW OBJECTIVES Learn about :

The history of Passive SolarEnergy efficient designPassive Heating Passive CoolingDaylighting

WE DID NOT INHERIT THE EARTH FROM OUR PARENTS. WE ARE BORROWING IT FROM OUR CHILDREN.

CHIEF SEATTLE