Slicing Energy Use with Sharp Calculation Tools
A version of this article appears in the September/October 2003 issue of Home Energy Magazine.
September 01, 2003
How can a calculator save energy? The right kind of calculator can provide a rational basis for deciding which conservation measures are good investments for a particular building. Builders and consumers alike need a credible source of unbiased, reliable information, so Oak Ridge National Laboratory (ORNL) has developed a collection of Web-based energyefficiency calculators for buildings (www.ornl.gov/roofs+walls). Roof Radiation Control Calculator The Roof Radiation Control Calculator estimates the annual cost savings from installing radiation control on a low-slope roof.The calculator uses several variables. Solar reflectance determines how much solar energy the roof will reflect, and infrared emittance determines how much thermal energy is radiated away from a building. Infrared emittance is also important at night, because a roof with a greater infrared emittance will release more heat to the cold night sky, which is desirable in the summer but not in the winter. Another key factor in estimating radiation control is the amount of insulation beneath the roof surface.The more insulation there is, the hotter the roof surface will be during the day, which in turn ...
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