Split-air flow cooling and dehumidification system

Abstract

A split-air arrangement for cooling and dehumidifying air in an indoor conditioned space includes separate first and second courses created from an entering air stream. The first course passes through a desiccant device to remove humidity from the air, the air leaving the desiccant device passing through a first cooling coil to cool the air and the air leaving the first cooling coil entering a supply air plenum. The second course is directed through a first side of a heat exchanger, the air leaving the heat exchanger being heated by a heater element prior to picking up moisture from the desiccant device. Air leaving the desiccant device passes through a second side of the heat exchanger, and subsequently passes through a second cooling coil to cool and dehumidify the air in the second course. Exiting air is mixed with the first course air and returned to the conditioned space in which the process air flow is maximized relative to the regenerative air flow while still permitting effective latent cooling.

1 . A cooling arrangement for cooling and dehumidifying air in an indoor conditioned space, said cooling arrangement comprising first and second air streams created from an entering air stream from a conditioned space, in which said first course is directed through a desiccant device to remove humidity from the air, the air leaving the desiccant device passing through a first cooling coil to cool the air and the air leaving the first cooling coil entering a supply air plenum;
 said second course being directed through a first side of a heat exchanger, the air leaving the heat exchanger being heated by a heater element and passing through said desiccant device, the air leaving the desiccant device passing through a second side of said heat exchanger, and the air leaving a second pathway of said heat exchanger passing through a second cooling coil to cool and dehumidify the air in the second course, and the air exiting the second course passing to the supply air plenum, where it mixes with air of the first course, and then returns to the conditioned space,   said arrangement further comprising means for adjusting the ratio of process air flow relative to the regenerative air flow of the first and second air streams so as to produce greater efficiency.   
     
     
         2 . A cooling arrangement as recited according to  claim 1 , wherein the ratio of process air flow to regenerative air flow in said system is at least 75 to 25. 
     
     
         3 . A cooling arrangement as recited according to  claim 2 , wherein the ratio of process air flow to regenerative air flow in said system is at least 84 to 16. 
     
     
         4 . A cooling arrangement as recited according to  claim 1 , wherein said desiccant device is a rotating desiccant wheel, said wheel being defined by a physically split design. 
     
     
         5 . A cooling arrangement as recited according to  claim 4 , wherein the physical split in said desiccant wheel is such that about 80 percent of the desiccant wheel is accessed by the first air stream and about 20 percent of the rotating desiccant wheel is accessed by the second air stream. 
     
     
         6 . A cooling arrangement as recited according to  claim 4 , wherein the physical split in said desiccant wheel is at least 90/10. 
     
     
         7 . A cooling arrangement as recited according to  claim 1 , wherein said desiccant device comprises a rotating desiccant wheel, and in which said system includes means for selectively adjusting the speed of rotation of said wheel. 
     
     
         8 . A cooling arrangement as recited according to  claim 1 , further comprising means for selectively adjusting the rate of water from said source of cooling to each of said first and second cooling coils. 
     
     
         9 . A cooling arrangement as recited according to  claim 1 , further including means for adjusting the temperature of air over said second course prior to picking up moisture from said desiccant device. 
     
     
         10 . A method for sensibly cooling and dehumidifying a conditioned space using a geothermal cooling source, said method including the steps of:
 ducting air from the conditioned space and separating said air into respective first and second air streams;   moving the first air stream through one side of a desiccant wheel to remove moisture from said air stream;   moving the first air stream through a first cooling coil;   moving said second air stream through one side of a regenerative heat exchanger and sequentially through a heat source and the second side of the desiccant wheel, said second air stream picking up moisture removed from the first air stream;   moving said second air stream through the second side of the regenerative heat exchanger, and subsequently to said second cooling coil, each of said first and second cooling coils being connected to a relatively warm source of water; and   mixing the second air stream and the first air stream and moving the mixed air to the conditioned space, said method including the additional step of   adjusting the ratio of process air flow relative to regenerative air flow of the first and second air streams in order to optimize system efficiency.   
     
     
         11 . A method for improving efficiency according to  claim 10 , including the step of configuring process air flow to regenerative air flow such that the ratio of process air flow to regenerative air flow is at least 80/20. 
     
     
         12 . A method for improving system efficiency according to  claim 10 , including the step of providing a desiccant wheel having a physically split design. 
     
     
         13 . A method as recited according to  claim 12 , wherein the physical split in said permits at least 80/20 in which only 20 percent of the area of said wheel is accessible to said second air stream. 
     
     
         14 . A method as recited according to  claim 13 , wherein the physical split in said desiccant wheel is at least 90/10. 
     
     
         15 . A method as recited according to  claim 12 , wherein said desiccant device comprises a desiccant wheel, said method including the additional step of selectively adjusting the speed of rotation of said desiccant wheel. 
     
     
         16 . A method as recited according to  claim 15 , including the step of slowing the speed of rotation of said desiccant wheel from a first speed of rotation to a second speed of rotation sufficient to maintain a sensible heat ratio of no more than 75 percent. 
     
     
         17 . A method as recited according to  claim 16 , wherein said second speed of rotation is about 6 revolutions per hour. 
     
     
         18 . A method as recited according to  claim 10 , including the additional step of selectively adjusting the rate of water from said source of cooling to each of said first and second cooling coils. 
     
     
         19 . A method as recited according to  claim 10 , including the additional step of adjusting the temperature of air over said second course prior to picking up moisture from said desiccant device. 
     
     
         20 . A method as recited according to  claim 19 , wherein said temperature adjusting step includes the step of minimizing the temperature of air in said second course to a value that still permits moisture to be picked up from the desiccant device. 
     
     
         21 . A method as recited according to  claim 10 , including the additional step of inserting at least one balancing damper in the second air stream to permit reduction of said flow. 
     
     
         22 . A control system for a split-air cooling arrangement, including first and air course from an indoor conditioned space, in which said first course passes through a desiccant device to remove humidity from the air, the air leaving the desiccant device passing through a first cooling coil to cool the air and the air leaving the first cooling coil entering a supply air plenum;
 said second course being directed through a first side of a heat exchanger, the air leaving the heat exchanger being heated by a heater element and passing through said desiccant device, the air leaving the desiccant device passing through a second side of said heat exchanger, and the air leaving the second pathway of said heat exchanger passing through a second cooling coil to cool and dehumidify the air in the second course, and the air exiting the second course passing to the supply air plenum, where it mixes with air of the first course and then returns to the conditioned space, said control system enabling said system to operate in various modes.   
     
     
         23 . A control system as recited in  claim 22 , including a microprocessor connected to each of the components of said arrangement, said microprocessor being programmed to enable each of said modes. 
     
     
         24 . A control system as recited in  claim 22 , wherein said various modes includes a mode in which only sensible cooling is performed. 
     
     
         25 . A control system as recited in  claim 22 , wherein said various modes includes a mode in which only latent cooling is performed.