| 摘要 |
<p>A retractable vent system includes extendable portions that can be extended or retraced to position an inlet or outlet end of the vent at different locations. The extendable portion may be manually movable or power operated. The inventors have discovered that a room can be heated and cooled more efficiently if the location of the vents supplying air into the room and the location at which air is withdrawn from the room is varied, depending on whether heated or cooled air is being delivered into the room. Based on testing, the inventors have determined that when a heating operation is being conducted, the highest efficiencies are obtained if heated air is delivered into the upper portion of the room.</p> |
