Patent ID: 8365542
Filing Date: 2013-02-05
Classification: F24F,F25B

Abstract:
1. An energy efficient frost free sub zero air conditioner comprising: a plurality of precooling coils for receiving the air to be conditioned; at least one pair of cooling systems for receiving said air to be conditioned from said precooling coils, and providing a continuous supply of conditioned air at a dew point that is several degrees Celsius below zero, each of said pair of cooling systems comprising: at least one electric fan for delivering said conditioned air from said second cooling system into an area to be conditioned; at least one refrigeration circuit comprising at least one compressor, a condenser coil, and a second electric fan for cooling said condenser coil; a plurality of heat recovery coils to recover heat from said precooling coils; a plurality of reheating coils for providing reheating of said conditioned air after it leaves said electric fan, to prevent initiation of a defrost cycle of the air conditioner; a plurality of pipes for connecting said cooling coils of said first and second cooling systems, said condenser coils, said heat recovery coils, and said reheating coils; a control circuit for controlling a flow of said refrigerant through said cooling coils of said second cooling system to prevent ice formation in said cooling coils of said second cooling system; wherein said air at said first temperature exiting said first cooling system is provided in a proportion to each of said cooling coils of the second cooling system, and wherein said control circuit keeps a portion of the cooling coils of the second cooling in an active mode by allowing said flow of said refrigerant through said portion of said cooling coils of the second cooling system, while keeping a remainder of said cooling coils of the second cooling in an inactive mode by disallowing said flow of said refrigerant through said remainder of said cooling coils, so that the total air flow from the second cooling system is an approximately 50% mixture of air at said first temperature and air at said second temperature.