Abstract:
A system and method for climate control of an enclosure that includes two climate control systems configured to operate in conjunction to cool the enclosure. One climate control system may be configured to control the operation of the other climate control system. The climate control systems operate depending on the temperature of certain areas.

Description:
CLAIM OF PRIORITY 
       [0001]    The present application claims priority to U.S. Provisional Patent Application Ser. No. 61/146,237, filed Jan. 21, 2009, entitled “An Improved Climate Control System For An Enclosure,” the entire disclosure of which is hereby incorporated by reference for all purposes as if set forth verbatim herein. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to a climate control system for an enclosure, such as an enclosure housing heat-sensitive equipment. 
       BACKGROUND OF THE INVENTION 
       [0003]    Electronic or other heat-sensitive equipment may be housed in various cabinets and other enclosures, such as cellular tower base cabinets, industrial power cabinets, and neighborhood wireline cabinets for telephone lines, cables transmitting television signals, or cables providing Internet access. The environment inside the enclosure surrounding the equipment typically must be maintained in a specific manner to prevent damage to the equipment. External factors, such as temperature, dust, salt, and humidity, can affect the equipment within the enclosure. 
         [0004]    A climate control unit (“CCU”) may be used to control the enclosure&#39;s internal environment and may be further designed to reduce or eliminate the entry of some or all of the external contaminants. The CCU also attempts to maintain the temperature of the enclosure&#39;s internal environment at a predefined temperature or temperature range. 
         [0005]    An above ambient CCU (“AACCU”), such as a heat exchanger, has been used to cool such electronic enclosures. An AACCU can lower the internal temperature of the enclosure but cannot reduce the temperature below ambient. In some instances, a below ambient CCU (“BACCU”), such as an air conditioner, replaces the AACCU as the CCU used to cool an enclosure. A BACCU can typically maintain an enclosure at a lower temperature than an AACCU because it is capable of cooling below the ambient temperature. However, the BACCU is usually accompanied by greater operational costs due to its higher energy consumption. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention recognizes and addresses the foregoing considerations, and others, of prior art construction and methods. 
         [0007]    In this regard, one aspect of the present invention provides a climate control system for an enclosure comprising a first climate control unit connected to the enclosure and including a first control circuit configured to operate the first climate control unit, and a second climate control unit connected to the enclosure and including a second control circuit configured to operate the second climate control unit and operatively connected to the first control circuit, where the first control circuit instructs the second control circuit to operate the second climate control unit to cool the enclosure. 
         [0008]    Another aspect of the present invention provides a method for cooling an enclosure comprising providing a first climate control unit connected to the enclosure, the first climate control unit comprising a first control circuit configured to operate the first climate control unit, and providing a second climate control unit connected to the enclosure, the second climate control unit comprising a second control circuit configured to operate the second climate control unit and operatively connected to the first control circuit, wherein the first control unit instructs the second control circuit to operate the second climate control unit to cool the enclosure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    A full and enabling disclosure of the present invention, including the best mode thereof directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended drawings, in which: 
           [0010]      FIG. 1  is a diagrammatic representation of a climate control system for an enclosure in accordance with an embodiment of the present invention; 
           [0011]      FIG. 2  is a perspective view, partially cut away, of a climate control unit that may be utilized in the climate control system of  FIG. 1 ; 
           [0012]      FIG. 3  is a perspective view, partially cut away, of another climate control unit that may be utilized in the climate control system of  FIG. 1 ; and 
           [0013]      FIG. 4  is a flowchart representing an exemplary process performed by the climate control system of  FIG. 1 . 
       
    
    
       [0014]    Repeat use of reference characters in the present specification and drawings is intended to represent same or analogous features or elements of the invention. 
       DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0015]    Reference will now be made in detail to presently preferred embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that modifications and variations can be made in the present invention without departing from the scope or spirit thereof. For instance, features illustrated or described as part of one embodiment may be used on another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents. 
         [0016]      FIG. 1  illustrates a climate control system  100  in accordance with an embodiment of the present invention. Climate control system  100  comprises a first climate control unit (“CCU”)  102  and a second CCU  104  connected to an enclosure  106 . Enclosure  106  will typically contain electrical or electronic equipment or various types of wiring. As one skilled in the art will appreciate, enclosure  106  protects its contents from external contaminants, such as dust, salt, and moisture. 
         [0017]    CCU  102  includes a control board  108  configured to control the operation of CCU  102 . Control board  108  comprises a processing device  110  operatively connected to readable medium  112 . It should be understood that processing device  110  may be a processor, microprocessor, controller, microcontroller, or other processing device, while readable medium  112  may be any type of media or memory readable or otherwise accessible by the processing device, including random access memory (“RAM”), flash memory, erasable programmable read-only-memory or an “EPROM,” cache, registers, etc. 
         [0018]    Similarly, CCU  104  comprises a control board  114  configured to operate CCU  104  and having a processing device  116  operatively connected to readable medium  118 . In another embodiment, control boards  108  and  114  comprise a number of relays configured to control operation of respective CCUs  102  and  104  and to accomplish a climate control method such as that described in detail below with respect to  FIG. 4 . 
         [0019]    A data path  120  operatively connects control boards  108  and  114 , allowing the control boards to communicate or otherwise transmit data or instructions. In one embodiment, data path  120  is a wired serial communication channel, such as an RS-485 serial cable. Alternatively, data path  120  may be wired, wireless, or any other means suitable to allow control boards  108  and  114  to communicate. It should be understood that wireless encompasses wireless protocols and technologies suitable to facilitate communication between two devices, including Bluetooth, wireless fidelity (“Wi-Fi”) ad hoc network connections, and cellular signals. 
         [0020]    In operation, CCUs  102  and  104  draw in air external to the CCUs (“ambient air”) near the base of the CCUs as indicated by arrows  122 . Air from enclosure  106  (“internal air”) enters CCUs  102  and  104  near the top surface of the respective CCU indicated by arrows  124 . Through a heat energy exchange process described in more detail below, heat energy is transferred from the internal air to the ambient air, thereby cooling the air returning to enclosure  106 , as indicated by arrows  126 , and heating the air returning to the area outside of the enclosure, as indicated by arrows  128 . 
         [0021]    Sensors adapted to measure the temperature of air are located in the path of flow of the air entering CCU  102  from enclosure  106  (“internal air temperature”) and air entering CCU  102  from the ambient (“ambient air temperature”). In the present embodiment, the temperature sensors are cable sensors adapted to measure the temperature of air passing the sensors, although it should be understood that any suitable sensors configured to measure the temperature of air may be used. As described below, control board  108  activates and deactivates CCU  102  based on an analysis of the temperatures measured by the sensors. The sensors may continue to measure the temperatures of the internal and ambient air even when CCU  102  is deactivated in order to perform methodology in accordance with the present invention. Likewise, control board  108  instructs control board  114  to activate and deactivate CCU  104  based on analysis of the temperatures. 
         [0022]    It should be understood that CCU  102 , CCU  104 , and enclosure  106  are preferably constructed to preserve the internal air within the enclosure and within internal compartments of the CCUs. That is, the configuration of CCUs  102  and  104  in combination with enclosure  106  allows the exchange of heat energy between the ambient and internal air without mixing the two in order to prevent contamination of the internal air or the introduction of dust, sand, or other contaminants to the enclosure. 
         [0023]      FIG. 2  illustrates CCU  102  connected to enclosure  106  in accordance with an embodiment of the present invention. In this embodiment, CCU  102  is a heat exchanger comprising an internal fan  202 , an ambient fan  204 , a heat exchange element  206 , and external vents  208  and  210 . Internal ports or other vents are also provided for ingress and egress of air internal to enclosure  106 . Control board  108  is operatively connected to, and controls the operation of, fans  202  and  204 . For example, fans  202  and  204  may be variable speed fans that operate at different speeds as commanded by control board  108 . Control board  108  is also operatively connected to the sensors measuring the internal and ambient air temperatures. As noted above, data path  120  operatively connects control board  108  to control board  114  ( FIG. 1 ). 
         [0024]    In operation, internal fan  202  draws the internal air into CCU  102  indicated by arrow  212  via an internal port. The internal air then passes through heat exchange element  206  and back into enclosure  106  indicated by arrow  214  through another internal port defined between the enclosure and the CCU. Ambient air is drawn into CCU  102  through vent  208  by ambient fan  204  as indicated by arrow  216 . The ambient air then passes over heat exchange element  206  and is returned to the exterior through vent  210  as indicated by arrow  218 . Heat exchange element  206  facilitates the transfer of heat energy from the internal air passing through the element to the ambient air passing over the element. 
         [0025]    Control board  108  preferably controls the activation and speed of fans  202  and  204  (and thus the operation of CCU  102 ) based on the difference between the internal air temperature and a predefined maximum desired temperature of the internal air (hereinafter “VALUE 1 ” for purposes of explanation). For example, the greater the internal air temperature is in comparison to VALUE 1 , control board  108  increases the speed of fans  202  and  204 . In contrast, if the temperature sensors indicate the ambient air is sufficiently greater than the internal air temperature, control board  108  deactivates fan  204  to prevent relatively warmer ambient air from being drawn into CCU  102 . This prevents an exchange of heat from the ambient air to the internal air, opposite to the desired direction of heat exchange. 
         [0026]    The operation and construction of heat exchanger  102  should be understood to those of ordinary skill in the relevant art and is, therefore, not described in more detail. It should be understood that CCU  102  may be any other CCU known to those in the art, including either an AACCU, such as a direct air cooling unit, one or more heat pipes, or a plurality of fins, or a BACCU, such as an air conditioning unit, a thermoelectric cooling unit, or a ground source cooling unit. Control board  108  instructs control board  114  ( FIG. 1 ) to activate and deactivate CCU  104  ( FIG. 1 ) via a process such as is described in detail below. 
         [0027]      FIG. 3  illustrates CCU  104  connected to enclosure  106  in accordance with an embodiment of the present invention. In this embodiment, CCU  104  is an air-conditioning unit comprising components that perform a refrigeration cycle including an evaporator  302 , a compressor  304 , and a condenser  306 . These refrigeration cycle components are interconnected by a set of pipes, through which a refrigerant flows. CCU  104  also comprises vents  308  and  310 , as well as a fan  312 . Each major component of the refrigeration cycle is operatively connected to control board  114  to allow the board to control the operation of the refrigeration cycle. 
         [0028]    In operation, CCU  104  functions to cool the refrigerant within the pipes. An internal fan draws the internal air into CCU  104  via a port defined between the CCU and enclosure  106  as indicated by arrow  312 . The internal air passes a temperature sensor and is directed over the pipes containing the cooled refrigerant. Heat energy is transferred from the internal air to the refrigerant, thereby cooling the internal air and heating the refrigerant. The cooled internal air is then returned to enclosure  106  as indicated by arrow  314  via another port defined between the enclosure and CCU  104 . 
         [0029]    Ambient air is drawn into CCU  104  by fan  312  through vent  308  as indicated by arrow  316 . The heat dissipated from the refrigerant as it is cooled as a result of the refrigeration cycle is transferred to the ambient air, which then returns to the exterior of CCU  104  as indicated by arrow  318 . Control board  114  activates and deactivates the refrigeration cycle components based on a comparison of the internal air temperature and VALUE 1  when operating in an independent mode. That is, when the internal air temperature is greater than VALUE 1 , control board  114  activates CCU  104 . As explained in more detail below, control board  114  activates the components based on instructions from control board  108  ( FIG. 2 ) when operating in a dependent mode. 
         [0030]    In one embodiment, compressor  304  is a variable speed compressor, the speed of which is managed by control board  114  based on either the temperature comparison (in an independent mode) or instructions received from control board  108  ( FIG. 2 , in a dependent mode). CCU  104  otherwise operates and is constructed in a manner understood by those of ordinary skill in the relevant art. It should be understood that CCU  104  may be any CCU understood by those of ordinary skill in the art, including both AACCUs and BACCUs. 
         [0031]    As described above with respect to  FIGS. 1 ,  2 , and  3 , control board  108  controls the operation of CCU  102 , while control board  114  controls the operation of CCU  104 . Control board  108  activates and deactivates CCU  102  in accordance with instructions stored on medium  112  and instructs control board  114  via data path  120  to activate and deactivate CCU  104  in accordance with instructions stored on medium  112  when operating in a dependent mode, as described below. It should be understood that the reverse may also be true—control board  114  activates and deactivates CCU  104  and instructs control board  108  via data path  120  to activate and deactivate CCU  102  when operating in a dependent mode—without departing from the scope of the present invention. That is, either control board may act as the primary control board. As noted above, control boards  108  and  114  may alternatively be comprised of relays that control the operation of the respective CCU. 
         [0032]      FIG. 4  illustrates a method performed by control boards  108  and  114  in accordance with an exemplary embodiment of the present invention. Thus, referring to  FIG. 4  with occasional reference to components shown in  FIG. 1 , the process begins at step  400 , where power is supplied to CCUs  102  and  104 . Additionally, processor  110  initializes VALUE 1  to the maximum desired temperature of enclosure  106 , which, in one exemplary embodiment, is 30° C. At step  402 , control board  108  attempts to communicate with control board  114 , which may be accomplished by any suitable method known to those of ordinary skill in the art such as a ping query. In the presently-described embodiment, both control boards repeatedly send outgoing signals and listen for incoming signals, which allow the boards to synchronize communications. If control board  108  is unable to establish a connection with control board  114 , CCUs  102  and  104  are set to operate independently, at step  404 . Process flow loops back to step  402  and the process then repeats. 
         [0033]    In an independent mode, processor  110  of control board  108  activates and deactivates CCU  102  in accordance with the instructions stored on medium  112 . This includes activating and controlling the speed of fans  202  and  204  ( FIG. 2 ) based on the internal and ambient air temperatures. Likewise, processor  116  of control board  114  activates and deactivates CCU  104  in accordance with the instructions stored on medium  118 , which may include controlling the speed of compressor  304  ( FIG. 3 ). CCUs  102  and  104  operate independently until the control boards have established the communication link. 
         [0034]    If communication between the boards is established at step  402 , process flow continues to step  406 , where control board  108  determines whether the internal air temperature is greater than VALUE 1 . If so, process flow proceeds to step  408 , where control board  108  instructs control board  114  to activate CCU  104 . Process flow then proceeds to step  410 , where control board  108  determines whether the ambient air temperature is greater than a second predefined value (hereinafter “VALUE 2 ,” for purposes of explanation). In an exemplary embodiment, VALUE 2  is the result of an efficiency offset subtracted from VALUE 1 . The goal of the efficiency offset is to compensate for any discrepancies in the measurement of the temperature of the ambient air drawn into CCU  102  and the actual temperature of the ambient air. In the current embodiment, the offset is 5° C. 
         [0035]    If the ambient air temperature is not greater than VALUE 2 , process flow proceeds to step  412 , where control board  108  activates CCU  102 . If the ambient air temperature is greater than VALUE 2 , this indicates that use of CCU  102  would be inefficient in the current scenario. Accordingly, process flow proceeds to step  414 , where control board  108  deactivates CCU  102 . 
         [0036]    If the internal air temperature is not greater than VALUE 1  as determined at step  406 , then process flow proceeds to step  416 , where control board  108  instructs control board  114  to deactivate CCU  104 . At step  418 , the internal air temperature is compared to a third predefined value (hereinafter “VALUE 3 ,” for purposes of explanation) to determine if the internal air temperature is sufficiently low that CCU  102  may be deactivated. If the internal air temperature is not greater than VALUE 3 , control board  108  deactivates CCU  102  at step  414 . If the internal air temperature is greater than VALUE 3 , process flow proceeds to step  410  and continues in the manner described above. VALUE 3  is defined by the user of climate control system  100  and may depend on the enclosure&#39;s contents and the external environment of system  100 . For example, the user may desire CCU  102  to operate even in relative low temperatures and may thus set VALUE 3  to be equal to a very low temperature. 
         [0037]    It should also be understood that climate control system  100  may be configured so that CCU  102  is activated if the internal air temperature is not greater than VALUE 1  regardless of the specific internal air temperature. That is, the internal air temperature is not compared to VALUE 3  at step  418  in order to determine whether CCU  102  may be deactivated. In this embodiment, step  418  is omitted so that process flow proceeds from step  416  directly to step  410  to determine if use of CCU  102  in that scenario is efficient. 
         [0038]    The process described above is repeated as illustrated in  FIG. 4  by the process proceeding from steps  404 ,  412 , or  414  to step  402 . In another embodiment, once communication between control boards  108  and  114  has been established, the process flow does not return to step  402 , but proceeds from steps  412  and  414  to step  406 . The temperature sensors continuously measure the internal and ambient air temperatures, and the above process is continuously repeated. It should be understood, however, that climate control system  100  may be configured to perform the process of  FIG. 4  and to remeasure the temperatures following predefined intervals of time. 
         [0039]    The terms “activate” and “deactivate” as used above should be understood to indicate that the respective CCU operates in the manner described above with respect to  FIGS. 1 ,  2 , and  3 . In addition, if the process set forth in  FIG. 4  proceeds to a step requiring activation of a CCU, such as steps  408  and  412 , while the CCU is already operating, the CCU continues to operate. Similarly, if the process proceeds to a step requiring deactivation of a CCU, such as steps  414  and  416 , while the CCU is already deactivated or otherwise not operating, the CCU continues to remain deactivated. 
         [0040]    In another embodiment, and with reference to  FIG. 1 , one or more additional CCUs are attached to enclosure  106 . Each of the one or more additional CCUs may be either an AACCU or a BACCU and comprises a control board or relays configured to control the operation of the additional CCU. The control board of the additional CCU is operatively connected to control board  108  so that control board  108  instructs it to activate and deactivate the additional CCU based on an analysis of the internal and ambient air temperatures in a manner similar to that described above with respect to  FIG. 4 . 
         [0041]    While one or more preferred embodiments of the invention have been described above, it should be understood that any and all equivalent realizations of the present invention are included within the scope and spirit thereof. The embodiments depicted are presented by way of example only and are not intended as limitations upon the present invention. Thus, it should be understood by those of ordinary skill in this art that the present invention is not limited to these embodiments since modifications can be made. For example, aspects of one embodiment may be combined with aspects of other embodiments to yield still further embodiments. Therefore, it is contemplated that any and all such embodiments are included in the present invention as may fall within the scope and spirit thereof.