Abstract: Variable airflow energy efficient HVAC systems can be used to provide for a three duct air supply, a multi-zone air supply, and a two duct air supply. The systems include an air handling unit that defines a cooling circuit portion and an independent heating/bypass circuit portion. The two circuit portions may each have variable air dampers for admitting variable amounts of ambient and return air, and/or the cooling circuit portion and the heating/bypass circuit portion may each have an active cooling element. Corresponding methods are also disclosed.

Abstract: Variable airflow energy efficient HVAC systems can be used to provide for a three duct air supply, a multi-zone air supply, and a two duct air supply. The systems include an air handling unit that defines a cooling circuit portion and an independent heating/bypass circuit portion. The two circuit portions may each have variable air dampers for admitting variable amounts of ambient and return air, and/or the cooling circuit portion and the heating/bypass circuit portion may each have an active cooling element. Corresponding methods are also disclosed.

Abstract: An energy efficient HVAC system. The system provides a bypass air supply duct, an air handler having a bypass air supply circuit, and an air supply unit that utilize return air as a source of heat that would otherwise need to be provided by a heating coil if the air, cooled sufficiently to service interior zones of a building, is too cold for servicing perimeter zones of the building, as is typically the case when the outside air temperature is low.

Abstract: An energy efficient HVAC system. The system provides a bypass air supply duct, an air handler having a bypass air supply circuit, and an air supply unit that utilize return air as a source of heat that would otherwise need to be provided by a heating coil if the air, cooled sufficiently to service interior zones of a building, is too cold for servicing perimeter zones of the building, as is typically the case when the outside air temperature is low.

Abstract: An energy efficient HVAC system. The system provides a bypass air supply duct, an air handler having a bypass air supply circuit, and an air supply unit that utilize return air as a source of heat that would otherwise need to be provided by a heating coil if the air, cooled sufficiently to service interior zones of a building, is too cold for servicing perimeter zones of the building, as is typically the case when the outside air temperature is low.

Abstract: An energy efficient HVAC system. The system provides a bypass air supply duct, an air handler having a bypass air supply circuit, and an air supply unit that utilize return air as a source of heat that would otherwise need to be provided by a heating coil if the air, cooled sufficiently to service interior zones of a building, is too cold for servicing perimeter zones of the building, as is typically the case when the outside air temperature is low.