Passive solar design refers to the
conceptualisation and drawing of a building that takes advantage of
the sun's energy to heat and light a house or building.
In passive solar building design,
windows, walls and floors are made to collect, store, and
distribute solar energy in the form of heat in the winter and
reject solar heat in the summer. This is called passive solar
design or climatic design because it doesn't involve the use of
mechanical and electrical devices.
The key to designing a passive solar
building is to take advantage of the local climate.
Elements to be considered include
window placement and glazing type, thermal insulation, thermal mass
and shading.
Specific attention is directed to the
site and location of the dwelling, the prevailing climate, design
and construction, solar orientation, placement of
glazing-and-shading elements, and incorporation of thermal mass.
While these considerations may be directed to any building,
achieving an ideal solution requires careful integration of these
principles.
The ability to achieve these goals simultaneously is
fundamentally dependent on the seasonal variations in the sun's
path throughout the day.
Passively designed homes can look like
any other home, but efficiently regulate natural energy flows to
regulate the homes internal environment, creating a more
comfortable home that is less expensive to run.
The areas of glass, walls and roof are
also important. The insulation rating of roof and walls as well as
how the shade is used in summer, all play a part in the success of
a passive solar home. Science allows us to calculate the effect so
that decisions can be based on reality, rather than
speculation.
Effective passive solar design
incorporates the clever utilisation and integration of the
following design principles: orientation, ventilation, insulation,
thermal mass, lighting and vegetation.
The exterior environment, such as trees, shrubs and ponds can
cool, shade and protect a building. The use of trees, hedges
and tecto pergolas and other pergolas with vines can create summer
shading. For winter solar gain it is desirable to use
deciduous plants that drop their leaves in the autumn providing
year round passive solar benefits. Non-deciduous evergreen shrubs
and trees can be windbreaks at variable heights and distances to
create protection and shelter from winter wind chills. With mature
size appropriate native species and drought tolerant plants, drip
irrigation, mulching, and organic gardening practices reduce or
eliminate the need for energy-and-water-intensive irrigation, gas
powered garden equipment, and reduces the landfill waste footprint.
Solar powered landscape lighting and fountain pumps and covered
swimming pools and plunge pools with solar water heaters can reduce
the impact of such amenities.
Within a home or building control mechanisms (such as
manual-or-motorised interior insulated drapes, shutters, exterior
roll-down shade screens, or retractable awnings) can compensate for
differences caused by thermal lag or cloud cover, and help control
daily / hourly solar gain requirement variations.
Good use of lighting and reflection is also important. For
example, roofs should be light in colour. Inside the orientation
and placement of window sections, including skylights and
solartubes, to collect light are also paramount. Other creative
solutions involve the use of reflecting surfaces to admit daylight
into the interior of a building and painting walls in lighter
colours.
Passive solar design techniques can be
applied most easily to new buildings, but existing buildings can be
adapted or retrofitted.
Author: James Shaw