Passive Solar System Law and Legal Definition

According to 26 CFR 1.23-2 (Title 26, Internal Revenue; Chapter I, Internal Revenue Service, Department of the Treasury; Subchapter A, Income Tax; Part 1, Income Taxes; Normal Taxes and Surtaxes; Determination of Tax Liability; Changes in Rates During a Taxable Year), “a passive solar system is based on the use of conductive, convective, or radiant energy transfer. In order to qualify as a passive solar system, a solar system used for heating purposes must contain all of the following: a solar collection area, an absorber, a storage mass, a heat distribution method, and heat regulation devices. The term "solar collection area" means an expanse of transparent or translucent material, such as glass which is positioned in such a manner that the rays of the sun directly strike an absorber. The term "absorber" means a surface, such as a floor, that is exposed to the rays of the sun admitted through the solar collection area, which converts solar radiation into heat, and then transfers the heat to a storage mass. The term "storage mass" means material, such as masonry, that receives and holds heat from the absorber and later releases the heat to the interior of the dwelling. The storage mass must be of sufficient volume, depth, and thermal energy capacity to store and deliver adequate amounts of solar heat for the relative size of the dwelling. In addition, the storage mass must be located so that it is capable of distributing the stored heat directly to the habitable areas of the dwelling through a heat distribution method. The term "heat distribution method" means the release of radiant heating from the storage mass within the habitable areas of the dwelling, or convective heating from the storage mass through airflow paths provided by openings or by ducts in the storage mass, to habitable areas of the dwelling. The term "heat regulations devices" means shading or venting mechanisms (such as awnings or insulated drapes) to control the amount of solar heat admitted through the solar collection areas and nighttime insulation or its equivalent to control the amount of heat permitted to escape from the interior of the dwelling.”