HVAC desiccant wheel system and method

A refrigerant system for conditioning air for a comfort zone, the refrigerant system comprising:

• an enclosure defining an upstream air passageway, a downstream air passageway, and an intermediate air passageway therebetween, wherein the air passes sequentially through the upstream air passageway, the intermediate air passageway, and the downstream air passageway;
• a cooling coil disposed in the enclosure;
• a source associated with the cooling coil and providing a chilled fluid thereto;
• a blower in a position to force the air from the downstream air passageway into the comfort zone;
• a desiccant wheel able to absorb moisture from the air passing from the intermediate air passageway to the supply air passageway and simultaneously release moisture to the air passing from the upstream air passageway to the intermediate air passageway;
• and
• a controller connected to selectively start and stop the source and selectively energize and de-energize the desiccant wheel for rotation, wherein the controller upon stopping the source energizes the desiccant wheel for a predetermined limited period, whereby the desiccant wheel during the predetermined limited period continues to provide cooling and/or dehumidification after the source stops.

A method of conditioning air for a comfort zone, the method comprising:

• defining an upstream air passageway, a downstream air passageway, and an intermediate air passageway therebetween, passing air sequentially through the upstream air passageway, the intermediate air passageway, and the downstream air passageway;
• disposing a cooling coil in the enclosure;
• associating a source with the cooling coil and providing a chilled fluid thereto;
• positioning a blower to force the air from the downstream air passageway into the comfort zone;
• absorbing moisture from the air passing from the intermediate air passageway to the supply air passageway and simultaneously releasing moisture to the air passing from the upstream air passageway to the intermediate air passageway;
• selectively starting and stopping the source;
• selectively energizing and de-energizing the desiccant wheel for rotation;
• and
• energizing the desiccant wheel for a predetermined limited period upon stopping the source whereby the desiccant wheel during the predetermined limited period continues to provide cooling and/or dehumidification after the source stops.

A system for conditioning air for a comfort zone comprising:

• an upstream air passageway, a downstream air passageway, and an intermediate air passageway therebetween,
• means for passing air sequentially through the upstream air passageway, the intermediate air passageway, and the downstream air passageway;
• a cooling coil in the enclosure;
• a source associated with the cooling coil and providing a chilled fluid thereto;
• a blower positioned to force the air from the downstream air passageway into the comfort zone;
• a desiccant wheel absorbing moisture from the air passing from the intermediate air passageway to the supply air passageway and simultaneously releasing moisture to the air passing from the upstream air passageway to the intermediate air passageway;
• means for selectively starting and stopping the source;
• means for selectively energizing and de-energizing the desiccant wheel for rotation;
• and
• means for energizing the desiccant wheel for a predetermined limited period upon stopping the source whereby the desiccant wheel during the predetermined limited period continues to provide cooling and/or dehumidification after the source stops.