Abstract:
An integrated air handling system having a make-up air system that treats outside air and a recirculating system that mixes the treated outside air with building return air. The make-up air system may include a filter, a dehumidifier, a humidifier, a combination of a dehumidifier and a humidifier, and/or an exhaust fan. The mixed air is supplied to a structure.

Description:
[0001]    This nonprovisional application claims the benefit of U.S. Provisional Application No. 61/510,830, filed Jul. 22, 2011. 
     
    
     BACKGROUND 
       [0002]    This disclosure is directed to systems and methods to integrate a make-up air Dedicated Outdoor Air System with recirculation air handling systems, for example, to provide air to a data center, in an efficient and effective manner. 
         [0003]    Make-up air is generally required in commercial spaces to satisfy codes and provide positive pressurization so as to reduce unwanted infiltration of unconditioned outdoor air. Make-up air is generally introduced by a machine separate from a recirculation air handler. This make-up air may be introduced by a Dedicated Outdoor Air System (DOAS), which processes the outdoor air prior to its entering a building. The DOAS processing often includes humidifying, dehumidifying, cooling and heating. 
         [0004]    A typical make-up air system, with a Humidification or a Dehumidification/Humidification Unit, is known and disclosed in U.S. patent application Ser. No. 12/929,002. 
         [0005]    The typical approach of introducing make-up air at a separate location from the system carries inherent disadvantages with regards to efficiency and effectiveness. There is a need, especially in cases where buildings have large recirculating air handling systems, for example, in a data center, to integrate the make-up air system with a recirculating air handling system to improve efficiency and reduce costs. 
       SUMMARY 
       [0006]    Disclosed herein is a DOAS system that provides controlled ventilation introduction integrated into a recirculation air handling system. The system may include a make-up air module that has the ability to, for example, filter ventilation air, dehumidify and humidify, as needed to, for example, control building pressure and dew point. 
         [0007]    This integration allows for a complete and efficient method and apparatus for introducing and conditioning the required amount of make-up air. The effects of the integration may include optimal energy efficiency, improved ventilation effectiveness, ease of control, reduced installation costs, and smaller overall apparatus footprint. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  shows an embodiment of an integrated system that includes integrating a make-up air system with a recirculating air system. 
           [0009]      FIG. 2  shows an embodiment of an integrated system that additionally includes a dehumidification coil for humidity control within the make-up air system. 
           [0010]      FIG. 3  shows an embodiment of a portion of an integrated system that includes a humidification section within the recirculation air system. 
           [0011]      FIG. 4  shows an embodiment of an integrated system that includes both a recirculation air humidification section and a make-up air system with dehumidification coil. 
           [0012]      FIG. 5  shows an embodiment of an integrated system that includes a make-up air system with dehumidification coil and a recirculation air humidification section, that by implementation of isolation dampers further functions as an outdoor evaporatively cooled condenser for rejecting the heat of compression from the make-up air dehumidification process. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0013]    Referring to  FIG. 1 , which shows integrating make-up air into a recirculating air system, the outside air stream  140  enters the make-up air system. The outside air stream  140  may be processed through at least one make-up air filter  101  and through a make-up air supply fan  102 . The make-up air supply fan  102  regulates airflow through the make-up air system  100 . The make-up air supply fan  102  may be any type of fan, including plenum or scroll fans. 
         [0014]    The treated make-up air then may pass through an isolation damper (i.e., make-up air shutoff control)  103  and exits the make-up air system as treated make-up air (i.e., make-up system supply air)  141 . The isolation damper  103  may, for example, open when the ventilation function is operable and close as necessary to isolate the recirculating air system  120  from the ventilation air system for servicing or other reasons 
         [0015]    The treated make-up air  141  then mixes with the building recirculating air  150  upon entering the recirculating air system  120 . The combination of air has thus been adequately filtered to comply with relevant standards and the ventilation air delivered is intended to reduce unwanted infiltration into the building. 
         [0016]    The mixed air  151  is a combination of the treated make-up air  141  and the building recirculating air  150 . The make-up air volume is established by codes and as required to ensure proper indoor air quality and building pressurization. 
         [0017]    The mixed air  151  is then processed through the remainder of the recirculating air system  120  and enters the building as building supply air stream  152 . 
         [0018]    Referring to the embodiment shown in  FIG. 2 , where make-up air is integrated into a recirculation air system, the outside air stream  240  enters the make-up air system with dehumidification  200 . The outside air stream  240  may be processed through at least one make-up air filter  201 . 
         [0019]    Next, the outside air  240  may dehumidified by dehumidification device  202 . The dehumidification process may occur, for example, during humid ambient conditions as required to control the humidity of the building. The dehumidification process may occur when the dew point of the outdoor air is, for example, above 59° F. The dehumidification process may continue until the dew point of the outdoor air is, for example, less than the upper limit of ASHRAE recommended supply air dew point of 59° F. 
         [0020]    Any dehumidification device known in the art may be used as dehumidification device  202 , including, for example, a refrigeration or chilled water coil, or a desiccant wheel. 
         [0021]    Dehumidifying the outside air  240  may have the advantages of, for example, reducing the risk of mold and increasing comfort of those in the building, or reducing the risk of certain types of circuit board corrosion that might otherwise result from high humidity. 
         [0022]    Next, the dehumidified outside air  240  may be processed through make-up air supply fan  203 . The make-up air then passes through an isolation damper (i.e., make-up air shutoff control)  203  and exits the make-up air system as treated air (i.e., make-up system supply air)  241 . 
         [0023]    The treated make-up air then mixes with building recirculating air  250  upon entering the recirculating air system  220 . 
         [0024]    The mixed air  251  is a combination of the treated make-up air  241  and the building return air  250 . 
         [0025]    The mixed air  251 , which has been sufficiently dehumidified by virtue of the outside air  240  passing through the dehumidification device  203  of the make-up air system  200 , may then be processed through the remainder of the recirculating air system  210  and enters the building as building supply air stream  252 . 
         [0026]    Referring to the embodiment shown in  FIG. 3 , which includes a recirculation air side-stream humidification system  310 , which may be the humidification portion of a make-up air system, and the recirculating air system  320 , the side-stream air humidification system  310  may include a direct evaporative cooler (DEC)  312 , also known as an adiabatic type humidifier, and a humidification supply air fan  313 . 
         [0027]    The DEC  312  may be any type of direct evaporative cooler known in the art, for example, an evaporative media pad. 
         [0028]    Humidification may be accomplished by taking a separate side-stream of return air  350   a  from the building return air (recirculated air stream)  350  of a recirculating air system  320 . This side-stream of return air  350   a  may be passed through an isolation damper (i.e., humidification system intake shut-off control)  311  as humidification system intake air stream  351 , and then through DEC  312 , which cools and humidifies the humidification system intake air stream  351 . The humidification system intake air stream  351  may then be passed through a humidification system supply air fan  313  and then passed through an isolation damper (i.e., humidification system supply shut-off control)  314 . The resultant humidification system supply air stream  352  may then enter back into the recirculating air system  320 . The net result of the humidification process is humidification and cooling without need for pre-heat or steam. A further benefit of wet pad type humidification is that it does not require special water treatment such as Reverse Osmosis or DI as is often required for other forms of humidification. 
         [0029]    The side-stream air  350   a  may be warm, relatively dry air. An appropriate amount of moisture may be added to the recirculated air stream to satisfy, for example, the humidification requirements of the make-up air or building space or return air. 
         [0030]    The humidification system supply air stream  352  may then mix in an appropriate ratio with the building return air  350  upon entering the recirculating air system. The mixed air  351  is a combination of the humidification system supply air stream  352  and the building return air  350 . The ratio of humidification system air to make-up air volume may be any required ratio, for example, between 2:1 and 4:1. The mixed air  353  is then processed through the remainder of the recirculating air system and enters the building as building supply air  354 . 
         [0031]    Referring to the embodiment shown in  FIG. 4 , the make-up air system  400  with dehumidification and humidification system  410  are shown. The humidification system  410  may be considered part of, or in addition to, the make-up air system. 
         [0032]    In  FIG. 4 , outside air  440  enters the make-up air system  400  and building return air (recirculating air stream)  450  enters the recirculating air system  420 . The outside air  440  may be processed through at least one make-up air filter  401  and then through dehumidification device  402 , so as to be adequately dehumidified, if necessary. The outside air  440  may then be processed through a make-up air fan  403  before leaving the make-up air system through an isolation damper (make-up air shut-off)  404 . The dehumidification process may occur, for example, during humid ambient conditions as required to control the humidity of the building. The dehumidification process may occur when the dew point of the outdoor air is, for example, above 59° F. 
         [0033]    Any dehumidification device known in the art may be used as dehumidification device  404 , including, for example, a chilled water or refrigeration coil, or a desiccant wheel. 
         [0034]    The filtered air may exit the isolation damper  404  and continue as a make-up system supply air stream  441 . 
         [0035]    Additionally, in the side-stream humidification portion  410 , which may also be considered part of, or alternatively in addition to, the make-up air system, humidification may be accomplished by taking a separate side-stream of return air  450   a  from the building return air (recirculated air stream)  450  of a recirculating air system  420 . This side-stream of return air  450   a  may be passed through an isolation damper (i.e., humidification system intake shut-off control)  411  as humidification system intake air stream  451 , and then through DEC  412 , which cools and humidifies the humidification system intake air stream  451 . The humidification system intake air stream  451  may then be passed through a humidification system supply air fan  413  and then passed through an isolation damper (i.e., humidification system supply shut-off control)  414 . The resultant humidification system supply air stream  452  may then enter back into the recirculating air system  420 . The net result of the humidification process is humidification and cooling without need for pre-heat or steam. 
         [0036]    The humidification system supply air stream  452  may then mix in an appropriate ratio with the building return air  450  upon entering the recirculating air system. The mixed air  453  is a combination of the humidification system supply air stream  452  and the building return air  450 . The mixed air  453  is then processed through the remainder of the recirculating air system. 
         [0037]    Treated make-up air (from the make-up system supply air stream)  441  may then be mixed in an appropriate amount with the mixed air  453  or otherwise with recirculating air stream  450  upon entering the recirculating air system  420 . The combination of air has thus been adequately treated to comply with building codes, control building humidity, and to provide the necessary ventilation for proper indoor air quality and to reduce unwanted infiltration into the building. 
         [0038]    The resultant make-up mixed air  454  is at least a combination of the treated make-up air and the building return air. 
         [0039]    The make-up mixed air  454  may then be processed through the remainder of the recirculating air system  420  and enter the building as building supply air  455 . 
         [0040]    Referring to the embodiment shown in  FIG. 5 , the make-up air system  500  with dehumidification and humidification system  510  are shown. The humidification system  510  may be considered part of, or in addition to, the make-up air system. 
         [0041]    When both a humidification system  510  and a dehumidification make-up air system  500  are included, it may be advantageous to integrate within the humidification system an evaporatively-cooled condensing section for use with refrigeration-based dehumidification systems. During times when dehumidification is required, for example, when the dew point of the outside air (the make-up system intake)  540  is greater than 59° F. This may be accomplished by isolating the humidification loop from the recirculating system  510  entirely, and instead allowing ambient air to be drawn through, using DEC  513  to create the evaporative cooling effect, and then exhausting cooled ambient air through a condenser coil  516 , where the heat of compression from the dehumidification system is rejected. 
         [0042]    Thus, in  FIG. 5 , outside air  540  may be processed through make-up air filters  501 . Next, the outside air  540  may be processed through dehumidification system  502 , so as to be adequately dehumidified. The outside air  540  may then be processed through make-up air supply fan  503  and passed through isolation damper (i.e., make-up air shutoff control)  504 . The make-up air then leaves the make-up air system as make-up system supply air stream  541 . 
         [0043]    Make-up system supply air  541  may then be mixed with building return air  550  to form mixed air  554 . 
         [0044]    The mixed air  554  may then be processed through the remainder of the recirculating air system  520  and enter the building as building supply air stream  555 . 
         [0045]    During make-up air dehumidification, outside air  560  may also enter the humidification system  510  through isolation damper (condenser system outside air shut-off)  512 . Outside air  560  may then pass through DEC  513  and may be evaporatively cooled. Outside air  560  may then pass through at least one humidification system supply air fan  514 . The air may then be exhausted through a condenser coil  516 . Exhausted air  561  then may exit the system through isolation damper (condenser system exhaust shut-off)  517  without entering the recirculating system. 
         [0046]    Additionally, in the side-stream humidification portion  510 , which may also be considered part of, or alternatively in addition to, the make-up air system, humidification may be accomplished by taking a separate side-stream of return air  550   a  from the building return air (recirculated air stream)  550  of a recirculating air system  520 . This side-stream of return air  550   a  may be passed through an isolation damper (i.e., humidification system intake shut-off control)  511  as humidification system intake air stream  551 , and then through DEC  513 , which cools and humidifies the humidification system intake air stream  551 . The humidification system intake air stream  551  may then be passed through a humidification system supply air fan  514  and then passed through an isolation damper (i.e., humidification system supply shut-off control)  515 . The resultant humidification system supply airstream  552  may then enter back into the recirculating air system  520 . The net result of the humidification process is humidification and cooling without need for pre-heat or steam. 
         [0047]    The humidification system supply air stream  552  may then mix with the building return air  550  upon entering the recirculating air system. The mixed air  553  is a combination of the humidification system supply air stream  552  and the building return air  550 . The mixed air  553  is then processed through the remainder of the recirculating air system. Note that humidification and dehumidification are independent processes that never occur at the same time. 
         [0048]    The make-up air system  500  may be controlled by a larger air-handling unit control system, or by a separate controller. The make-up air system  500  may receive power from the main air handling unit control feed, a dedicated power feed, or another power feed. 
         [0049]    The make-up air system filters  501  may optionally include, for example, a pre-filter and a final filter. The pre-filter may, for example, be about 2 inches deep and have a minimum efficiency reporting value (MERV) of 8. 
         [0050]    The final filter may be, for example, about 4 inches deep. The final filter may have, for example, a MERV rating of 11, 13 or higher. 
         [0051]    Finally, it should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be capable of designing many alternative embodiments without departing from the scope of the invention as defined by the appended claims. In the claims, any reference signs placed in parentheses shall not be construed as limiting the claims. The word “comprising” and “comprises,” and the like, does not exclude the presence of elements or steps other than those listed in any claim or the specification as a whole. The singular reference of an element does not exclude the plural reference of such elements and vice-versa. In a device claim enumerating several means, several of these means may be embodied by one and the same item of software or hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.