Air handler with return air bypass for improved dehumidification
AssigneeAmerican Standard International Inc.
InventorsRadhakrishna Ganesh, Jeffrey A. Moore, Brian J. Fiegen
Life of this patent
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Abstract
A VAV air handler includes a cooling coil with a return air bypass damper for improved dehumidification. The bypass interjects into the supply air a portion of relatively warm, dry return air downstream of the cooling coil. This allows the cooling coil to absorb more latent heat from the incoming outside air and the remaining portion of the return air over a broad range of operating conditions, but especially at low load conditions.
Claims14
An air handling system selectively operable in a full load condition and a low load condition to meet a cooling demand of a comfort zone by providing supply air to the comfort zone, comprising:
- a housing defining a return air inlet, a outside air inlet, a supply air outlet, a return air chamber, a precoil mixing area, and a postcoil mixing area, wherein the outside air inlet leads into the precoil mixing area;
- a cooling coil disposed downstream of the precoil mixing area and upstream of the postcoil mixing area and being adapted to cool air moving from the precoil mixing area to the postcoil mixing area;
- a damper system disposed downstream of the return air chamber and being adapted to receive air from the return air chamber and apportion the air to the precoil mixing area and the postcoil mixing area, wherein the temperature of supply air in the postcoil mixing area is higher in the low load condition than in the full load condition;
- and
- a blower coupled to the housing and being adapted to move supply air from the postcoil mixing area to the comfort zone, wherein the blower moves the supply air at a higher flow rate in the full load condition than at the low load condition.
A method of handling supply air, return air, and outside air to meet a varying cooling demand of a comfort zone within a building, wherein the supply air enters the comfort zone, the return air exits the comfort zone, and the outside air comes from outside the building, comprising:
- separating the return air into a first portion of return air and a second portion of return air;
- creating a first mixture of the first portion of return air and the outside air;
- cooling the first mixture;
- mixing the second portion of return air and the first mixture to create the supply air;
- conveying the supply air to the comfort zone;
- and
- upon the cooling demand having decreased, reducing an airflow rate of the supply air and increasing a ratio of the second portion of return air to the first portion of return air.
Dependencies are inferred from the claim text.