Design Strategies
This strategy admits solar radiation into living space.
What is a direct gain system?
This instrument reveals the hours of the year during which a position is shaded by trees, buildings, and other nearby objects.
What is a solar pathfinder?
This is the direction from which most solar energy emanates under overcast skies.
What is the top of the sky dome?
These are the I-P units that correspond to a lighting power density given in W/sf.
What is Btu/h-sf?
These three components are the primary contributors to internal heat gains in buildings.
What are people, lights, and equipment?
This strategy collects solar radiation in an enclosed room that is thermally separate from living space.
What is an isolated gain system, or alternatively, a sunspace?
The lowest possible U-value in a window assembly is not always the best choice for this particular reason.
The SHGC may be too low for desired solar gain.
This is the outdoor air temperature at which a building's internal and solar heat gains equal its losses through the solid envelope and infiltration.
What is the balance-point temperature?
This is the unit of power that corresponds to energy transfer at the rate of one Joule per second.
What is a Watt?
This quantity combines conductive, convective, and radiative heat transfer coefficients into one material property.
What is the U-value?
This strategy should be considered when a solar heat-collecting room with outdoor character is desired, but the equator-facing facade is not available for solar collection.
What is an atrium?
This is the position of solar-collecting glazing that receives the greatest possible incident solar radiation during the heating season.
What is the optimal passive heating tilt? (or even better, optimal orientation and tilt!)
This angular measurement is significantly smaller on the winter solstice than on an equinox.
What is the solar altitude?
This quantity describes the energy that is transferred through a unit area in a unit of time.
What is heat flux?
At this particular outdoor air temperature, a building needs neither heating nor cooling.
What is the balance-point temperature?
This solar collection strategy depends on sunny winters because its collection surface is vertical.
What is a Trombe wall?
The impacts of these site shading elements are best measured in the winter, when their effects on winter solar collection are most apparent.
What are deciduous trees?
The existence of this quantity requires a pathfinder in Eugene, Oregon to be oriented such that the compass needle points 15 degrees west of north.
What is the magnetic declination?
This is the unit that expresses the energy transferred at a rate of one thousand Joules per second for a duration of one hour.
What is one kiloWatt-hour (kWh)?
This is the property of air that gives insulation made of foam or fluffy fibers its effectiveness in reducing the transfer of thermal energy across a wall or roof.
What is low thermal conductivity?
This strategy uses a shallow roof plenum and a fan to collect warm air and deliver it to living space.
What is a flat collector?
The position of solar-collecting glazing that receives the greatest possible incident solar radiation over a full year.
What is the optimal tilt for a PV array?
On this day, the azimuth of the sunrise is closer to south than it is on any other day of the year, in the Northern hemisphere.
What is the winter solstice?
This quantity is equal in magnitude to 1.8 degrees Fahrenheit.
What is one degree Celsius?
Tight edge sealing around movable insulation on a window is essential to reduce this process.
What is convection? or, What is the flow of air behind movable insulation?