High-efficiency air handler

Abstract

A high-efficiency air handler that is suitable for moving large volumes of air. The air handler comprises a coil and a fan. The total air volume moving through the unit is preferably over about 2000 CFM, with a total fan static pressure rise of less than about 0.5 inches and preferably less than 0.2 inches of water. The fan is preferably a modified ceiling fan with a rotational speed of less than about 450 rpm. The air handler is preferably part of a system where dehumidification and sensible cooling functions are separate. The separate dehumidification allows for much higher supply air temperatures, preferably within about 10° F. of the space temperature. Low-velocity air distribution through a ceiling plenum or a vent into the space allows for very low fan static pressures, which greatly reduces fan energy use compared to conventional ducted systems. The low static pressures and high supply-air temperatures allow the use of existing drop ceiling construction with little modification. The system can also include low-cost thermal storage. Latent thermal storage is in the form of a concentrated liquid desiccant solution. Chilled water storage is another option. The result is a major improvement in energy efficiency and comfort while reducing installed cost and peak electrical demand of the system.

1 ) An air handler for air conditioning buildings comprising: 
 a) A cooling coil that transfers thermal energy from air to a second fluid and    b) A fan with a total design airflow greater than about 2000 CFM and a design static pressure less than about 0.5 inches of water.    c) A flow path between said fan and said cooling coil so that said fan moves air over said cooling coil, which cools the air and thereby produces a cooled air stream.    
     
     
         2 ) The air handler of  claim 1  wherein said fan has a design static pressure rise of less than about 0.2 inches of water.  
     
     
         3 ) The air handler of  claim 2  wherein said fan has a design pressure rise of less than 0.05 inches of water.  
     
     
         4 ) The air handler of  claim 2  wherein the temperature of said cooled air stream is above the dewpoint temperature of air entering the air handler.  
     
     
         5 ) The air handler of  claim 2  wherein said fan is an axial-flow fan.  
     
     
         6 ) The air handler of  claim 2  wherein said fan is a radial flow fan.  
     
     
         7 ) The air handler of  claim 6  wherein said radial fan is a plenum fan with backwardly curved blades.  
     
     
         8 ) The air handler of  claim 2  wherein said fan has blade with an airfoil cross-section.  
     
     
         9 ) The air handler of  claim 2  wherein air leaving said air handler is discharged into a ceiling plenum.  
     
     
         10 ) The air handler of  claim 2  wherein said flow channel comprises a ceiling plenum.  
     
     
         11 ) A heat-exchange device comprising: 
 a) A heat exchanger for transferring heat between air and a second fluid,    b) An electric motor with a design rotational speed of less than about 500 rpm, and    c) An impeller that is directly driven by said motor that moves air across said heat exchanger.    
     
     
         12 ) The air handler of  claim 11  wherein said electric motor comprises an induction motor.  
     
     
         13 ) The air handler of  claim 12  wherein said electric motor has a synchronous speed of less than about 600 rpm.  
     
     
         14 ) The air handler of  claim 12  wherein said induction motor is a single-phase motor.  
     
     
         15 ) The air handler of  claim 12  wherein said induction motor is supplied with two-phase power.  
     
     
         16 ) The air handler of  claim 12  wherein the rotational speed of said induction motor is greater than about 70% of the synchronous speed.  
     
     
         17 ) An air handler comprising: 
 a) A fan,    b) A cooling coil with a design face velocity of less than 300 feet per minute, and    c) A flow path between said cooling coil and said fan so that said fan mover air through said cooling coil.    
     
     
         18 ) The air handler of  claim 17  wherein said cooling coil is less than 3 rows deep.  
     
     
         19 ) The air handler of  claim 18  wherein said cooling coil has a supply air temperature of above the dewpoint temperature of air entering said air handler.  
     
     
         20 ) The air handler of  claim 19  wherein said supply air temperature is above about 62 F.