Abstract:
A self-regulating cooling/heating system employs a variable flow manifold that allows the automatic re-direction of cooling/heating fluid (air, water, phase transition medium) to the areas of the cabinet or enclosure that requires the most cooling/heating. This enables a more efficient use of cooling/heating capability, sending the cooled/heated fluid to areas of greatest temperature differential, which will result in a greater amount of thermal energy being transferred to the cooling/heating medium. This technique yields more efficient electronics and systems.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     This invention relates generally to cooling and heating systems, and more particularly to a passively or actively temperature controlled, self-regulating method and system for cooling a liquid, gas, or phase transition medium to implement selective cooling of an operationally hot system or device, or heating of an operationally cold system or device in the same manner, to increase the system or device operating efficiency.  
         [0003]     2. Description of the Prior Art  
         [0004]     The cooling of fluids is desirable in many applications. Internal combustion engines, for example, run more efficiently if relatively high temperature fuel is cooled before being introduced into the combustion chamber.  
         [0005]     Hydraulic systems function better with cooler hydraulic fluid. Oil lubrication systems are more effective when the oil is cooled. This is true in transmissions and other parts of a power train as well as for the internal lubrication of an engine.  
         [0006]     More recently, advances in technology related to modern electronic systems and devices such as radar displays, for example, demand strategic cooling techniques having greater efficiencies and lower costs. Known cooling techniques can provide the desired efficiencies, but at cost parameters that are simply non-competitive in the modern marketplace. These modern electronic systems and devices run at faster operating speeds when properly cooled; and the expected system or device life is increased when operating temperatures are properly managed.  
         [0007]     Certain radar displays, for example, are very large, and for strategic reasons that may be related to the operational environment and the like, require passive cooling techniques. Since these arrays are so very large, only certain portions of such displays are used at any given moment in time. It is therefore not efficient to cool the whole radar array associated with the radar display unit, when instead, it is only necessary to cool that portion of the array that is being utilized, and thus is operating at an elevated temperature.  
         [0008]     In view of the foregoing background, it would be extremely beneficial and advantageous to provide a cooling system and method for cooling only that portion of an operationally hot device that is necessary to achieve a desired level of device operating efficiency, rather than using a known cooling and/or heat transfer technique that is limited to cooling the whole device. It would be further advantageous if the system and method for cooling were passively controlled and not dependent upon any type of active controller or control device, but could instead continue to fully function, even in the absence or failure, for example, of a system or device computerized controller.  
         [0009]     Consider now an array  10  having four sections such as shown in  FIGS. 1A, 1B  and  1 C. In  FIG. 1A , array  10  can be seen to exhibit section temperatures of 50° F. and 200° F. in the upper two sections from left to right respectively; while the lower two sections exhibit section temperatures of 60° F. and 50° F. from left to right respectively. Consider now also a convective cooling system; If a conventional uniform cooling approach is utilized to cool the array  10 , only 25% of the coolant may come into contact with the hot 200° F. area, quickly reaching the maximum heat flux of the cooling system. Thus, as seen in  FIG. 1B , the hot 200° F. area may cool down to only 150° F. Although better, the efficiency of uniform cooling falls short of the desired results. Consider now instead, a cooling system that directs 75% of the coolant fluid through the hot 200° F. zone, with the remaining 25% used for the other zones. Such a cooling system can be expected to extract heat more effectively. Smart cooling therefore, results in a more efficient transfer of thermal energy to yield the array temperatures depicted in  FIG. 1C .  
       SUMMARY OF THE INVENTION  
       [0010]     The present invention is directed to a passive or active, self-regulating cooling and/or heating system and method for providing a desired level of operating efficiency at a minimized cost level when compared with known cooling/heating systems and methods. The self-regulating cooling/heating system and method can direct a cooling/heating medium, e.g. liquid, gas, medium that changes state or undergoes a phase transition, through only those portions of a system or device that are operationally hot or cold, while substantially ignoring those portions of the system or device that are not operationally hot or cold or are otherwise operationally cool or hot.  
         [0011]     More specifically, one embodiment of the system or device is cooled in sections or portions that are independent from one another such that it is possible to selectively cool any one or more sections or portions, such as described herein before with reference to  FIGS. 1A-1C . In one embodiment, the coolant or cooling medium is exhausted from each section of the system or device into a manifold having a plurality of input ports. Each input port receives the coolant or cooling medium solely from a predetermined single section. The manifold has a single output port that transfers the cooling medium into a heat exchanger wherein the cooling medium is cooled. Such heat exchangers are well known in the art, and so will not be discussed in further detail herein to preserve brevity and enhance clarity. The cooled medium is then pumped back into the system or device. Each manifold input can contain a distinct passive or active temperature controlled flow control device that reacts only to the temperature of the cooling medium passing through the passive or active flow control device. Each flow control device could just as easily be positioned at each input port or output port associated with the system or device to be cooled. In this manner, each section or portion of the device or system to be cooled will receive only that amount of cooling medium or coolant necessary to efficiently cool the respective section or portion that needs to be cooled. This process then can be seen to be self-regulating since each passive or active flow control device reacts to pass or restrict the amount of coolant passing through its respective section or portion of the system or device. The operating efficiency is thus improved since the maximum quantity of return coolant need not necessarily pass through each portion of the device or system to be cooled. Only those sections or portions requiring enhanced cooling will see enhanced coolant flow there through.  
         [0012]     In one aspect of the invention, a self-regulating cooling system includes a first heat transfer device such as a manifold, having at least one fluidic input port and at least one fluidic output port; a second heat transfer device such as a heat exchanger, having at least one fluidic input port and at least one fluidic output port, wherein a fluidic medium is allowed to flow freely between the first and second heat transfer devices, such that thermal energy is transferred from the first heat transfer device to the second heat transfer device; and a self-regulating element operational to control the amount of thermal transfer from selected sections or portions of the first heat transfer device to the second heat transfer device. Fluidic flow is most preferably implemented via a suitable pump or other like device to maintain the thermal cycle.  
         [0013]     The self-regulating element is most preferably a passively controlled device, but could just as easily be an actively controlled device, that operates most preferably in response to temperature changes associated with the fluidic medium to regulate the amount of fluidic medium flowing through the selected portions or sections of the first heat transfer device. A suitable self-regulating element may comprise a variable orifice valve, for example, in which the size of the orifice is controlled via a thermal element such as a thermally responsive spring.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]     Other aspects, features and advantages of the present invention will be readily appreciated as the invention becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawing figures wherein:  
         [0015]      FIG. 1A  depicts a system or device array having four distinct heat/cool zones;  
         [0016]      FIG. 1B  shows the temperature effects of uniform cooling applied to the distinct heat/cool zones depicted in  FIG. 1A ;  
         [0017]      FIG. 1C  shows the temperature effects of smart cooling applied to the distinct heat/cool zones depicted in  FIG. 1A ;  
         [0018]      FIG. 2A  is a simplified system diagram illustrating a self-regulating cooling system according to one embodiment of the present invention;  
         [0019]      FIG. 2B  is an exploded view showing more details of the return manifold depicted in  FIG. 2A ;  
         [0020]      FIG. 3A  is a simplified system diagram illustrating a self-regulating cooling system according to another embodiment of the present invention;  
         [0021]      FIG. 3B  is an exploded view showing more details of the return manifold depicted in  FIG. 3A ;  
         [0022]      FIG. 4  is a simplified system diagram illustrating a self-regulating cooling system according to yet another embodiment of the present invention;  
         [0023]      FIG. 5  is a flow diagram illustrating a method of cooling a system or device according to one embodiment of the present invention;  
         [0024]      FIG. 6  is a diagram illustrating still another application of a self-regulating element in a cooling/heating system according to one embodiment of the present invention; and  
         [0025]      FIG. 7  illustrates a self-regulating element in a cooling/heating system with an active control unit according to one embodiment of the present invention. 
     
    
       [0026]     While the above-identified drawing figures set forth particular embodiments, other embodiments of the present invention are also contemplated, as noted in the discussion. In all cases, this disclosure presents illustrated embodiments of the present invention by way of representation and not limitation. Numerous other modifications and embodiments can be devised by those skilled in the art which fall within the scope and spirit of the principles of this invention.  
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0027]     The embodiments described in detail herein below are directed to a self-regulating cooling (or heating) system and method for passively or actively providing a desired level of operating efficiency at a minimized cost level when compared with known cooling and heating systems and methods that employ active control techniques. The self-regulating cooling/heating system and method, as stated herein before, can direct a cooling or heating (fluidic) medium, e.g. liquid, gas, medium that changes state or undergoes a phase transition, through only those portions of a system or device that are operationally hot or cold, while substantially ignoring those portions of the system or device that are not operationally hot or cold or are otherwise operationally cool or hot.  
         [0028]     Before moving to the Figures, it is important to note that the system or device to be cooled or heated is cooled or heated in sections or portions that are independent from one another such that it is possible to selectively cool or heat any one or more sections or portions. One embodiment, as stated herein before, exhausts the coolant or cooling medium from each section of the system or device into a first heat transfer device such as a manifold having a plurality of input ports. Each input port receives the coolant or cooling medium solely from a predetermined single section. The manifold may have one or more output ports that transfer the cooling medium into a second heat transfer device such as a heat exchanger where the cooling medium is cooled. Such heat exchangers, as stated herein before, are well known in the art, and so will not be discussed in further herein to preserve brevity and enhance clarity in describing the embodiments exemplified herein. In systems and/or devices that may run too cold, the process can be easily modified such that the liquid, gas, or phase transition medium is heated rather than cooled. Subsequent to cooling/heating, the cooled/heated fluidic medium is then pumped back into the system or device. Each manifold input can contain a distinct passive or active flow control device that reacts only to the temperature of the cooling/heating fluidic medium passing through the distinct flow control device. Each passive/active flow control device could just as easily be positioned at each input port or output port associated with the system or device to be cooled to selectively re-direct or restrict the coolant or heating medium flow through the individual sections of the device or system to be cooled or heated. In this manner, each section or portion of the device or system to be cooled or heated will receive only that amount of cooling/heating fluidic medium necessary to efficiently cool or heat the respective section or portion that needs to be cooled or heated. This process then can be seen to be self-regulating since each passive or active, self-regulating flow control device reacts to pass or restrict the amount of coolant or heating medium passing through its respective section or portion of the system or device, focusing on maximum efficiency i.e. maximum output for a given minimum input. The operating efficiency is thus improved since the maximum quantity of return coolant or heating medium need not necessarily pass through all portions of the device or system to be cooled or heated. Only those sections or portions requiring enhanced cooling will see enhanced coolant while those section or portions requiring enhanced heating will see less coolant flow there through respectively.  
         [0029]     Looking now at  FIG. 2A , a simplified block diagram illustrates a self-regulating cooling/heating system  100  according to one embodiment of the present invention. Self-regulating cooling/heating system  100  operates to cool or heat selected portions  112 ,  114 ,  116 ,  118 ,  120  of a radar array  110 . Each portion  112 - 120  of the radar array  110  is cooled or heated independently of any other portion as described below. Self-regulating cooling/heating system  100  can be seen to include a first heat transfer device  130  such as a manifold, having a plurality of input ports  132 ,  134 ,  136 ,  138 ,  140 . Each input port  132 - 140  is connected to a single unique portion or section  112 - 120  of the radar array  110 . Manifold  130  can be seen to also have a single output port  122 . Cooling/heating system  100  has a second heat transfer device  142 , such as a heat exchanger, that operates to cool or heat the coolant or heating medium that is employed to cool or heat the sections of the radar array  110 . Any suitable coolant or heating medium such as a liquid medium, gaseous medium, or coolant/heating medium, such as, but not limited to Freon, that changes state in response to temperature changes, can be employed, so long as the desired heat transfer characteristics are achieved. Heat exchanger  140  has a single input port  144  that receives coolant/heating medium from the single output port  122  of the manifold  130 . Subsequent to cooling or heating, the coolant or heating medium is exhausted via a single heat exchanger output port  146 , wherein the coolant or heating medium is redirected back to a coolant/heating medium input port associated with the radar array  110 .  
         [0030]     Looking now at  FIG. 2B , each of the output manifold input ports  132 ,  134 ,  136 ,  138 ,  140  can be seen to most preferably employ a passive self-regulating element  133 ,  135 ,  137 ,  139 ,  141 . Each passive self-regulating element  133 - 141  may, for example, comprise a variable orifice valve in which the orifice increasingly opens or closes in response to changes in the fluidic temperature. In this manner, each valve will continue to successfully operate, even in the absence of any type of active control, such as that which may be provided via a computerized control unit or system. The present invention is not so limited however, and it shall be understood that an actively controlled self-regulating element can also be employed to implement the smart cooling/heating described herein and thus provide the desired system or device operating efficiencies.  
         [0031]     In summary explanation, and with continued reference now to  FIG. 2B , a self-regulating cooling/heating system  100  can be seen to comprise a first heat transfer device (e.g. manifold)  130 , a second heat transfer device (e.g. heat exchanger)  142 , and at least one self-regulating element  133 ,  135 ,  137 ,  139 ,  141 , to cool or heat selected portions of a device or system (e.g. radar array)  110 . A suitable coolant or heating medium which may be in the form of a gas, liquid, or medium that undergoes a phase transition during the heat transfer process, passes through each section of the device or system (e.g. radar array)  110 . Only certain portions or sections  112 ,  114 ,  116 ,  118 ,  120 , of the array  110  may be operational at any given time; thus only those sections that are operational may have a need to be cooled or heated. Further, some sections of the array  110  may operate hotter or cooler than other sections of the array  110 , thus demanding more or less coolant or heating medium flow to achieve a desired cooling or heating effect. Coolant or heating medium is exhausted from each section of the radar array  100  into a unique input port of the manifold  130 , wherein a self-regulating element  133 ,  135 ,  137 ,  139 ,  141 , monitors the temperature of the exhausted coolant or heating medium. If the fluidic temperature is too high, the respective self-regulating element will operate in a non-restrictive mode to increase the size of an orifice that allows more of the coolant to pass through its associated section of the array  110  and quickly return that respective array section to a suitable operating temperature. If the fluidic temperature is not too high, the respective self-regulating element will operate in its restrictive mode to decrease the size of an orifice to decrease the amount of coolant passing through its associated section of the array  110 . The self-regulating elements  133 ,  135 ,  137 ,  139 ,  141  will operate continuously to variably increase and decrease the respective orifice openings in response to individual array section coolant temperatures to maintain a desired and substantially constant range or operational array temperatures. Alternatively, if the fluidic temperature is too low, the respective self-regulating element will operate in a restrictive mode to decrease the size of an orifice to allow less coolant to pass through its associated section of the array  110 , quickly returning that respective array section to a more suitable operating temperature.  
         [0032]     Those skilled in the cooling and heating arts will readily appreciate that the cooling principles described herein can just as easily be inversely applied to provide desired heating effects. Thus, a particular section of a system or device that may be operating too cool, may be more efficiently heated to a more suitable operating temperature by directing a larger percentage of a heating medium through that section, or alternatively, as described herein before, by directing a smaller percentage of a cooling medium through that section. In this manner, the overall system or device operating efficiency can thus be optimized by using a smart heating system rather than a more conventional uniform heating system that is familiar to those skilled in the heating art.  
         [0033]      FIG. 3A  is a simplified cooling system diagram illustrating a self-regulating cooling system  200  according to another embodiment of the present invention. Self-regulating cooling system  200  is similar to the cooling system  100  described herein before with reference to  FIGS. 2A and 2B ; except the self-regulating elements  133 ,  135 ,  137 ,  139 ,  141  can now be seen with reference to  FIG. 3B , to be positioned at the output ports of the input manifold  202  such that each self-regulating element  133 - 141  is positioned directly in line with an input port associated with any one of the array sections  112 ,  114 ,  116 ,  118 ,  120 . Each element  133 ,  135 ,  137 ,  139 ,  141  is thus in direct contact with the coolant flowing through an associated section of the radar array  110 , and therefore passively or actively “re-directs” and controls the rate at which coolant flows through its associated array section  112 - 120 .  
         [0034]     Moving now to  FIG. 4 , a simplified system diagram illustrates a self-regulating cooling system  300  according to yet another embodiment of the present invention. Self-regulating cooling system  300  can be seen to also include a first heat transfer device (e.g. manifold)  330 , a second heat transfer device (e.g. heat exchanger)  142 , and at least one self-regulating element  133 ,  135 ,  137 ,  139 ,  141 , to cool selected portions of a device or system (e.g. radar array)  110 . Unlike manifold  130  discussed herein before however, the manifold  330  in cooling system  300  can be seen to have only a single input port  332 . The entire coolant medium flowing through array  110  is therefore exhausted into the manifold  330  via the manifold single input port  332 . The array coolant medium is transmitted to the heat exchanger  142  where the medium is re-cooled. The re-cooled medium is pumped back to the array  110  via a suitable pump  310 , where at least one self-regulating element  133 ,  135 ,  137 ,  139 ,  141  operates as described herein before to variably and passively control the amount of coolant flowing through its associated section of the array  110 . Cooling system  300  thus operates to continuously cool the entire volume of coolant medium, while simultaneously, continuously and variably restricting the flow rate of re-cooled medium passing through each section of the array  110 .  
         [0035]     The present invention is not so limited however, and it shall be understood that each self-regulating element may be passively controlled or controlled via an active controller of some type. Passive control is most preferred, since the passive, self-regulating element will continue to function in its normal temperature sensing mode to control the variable orifice valve regardless of whether the control system or device remains operational. Further, as stated herein before, the inverse principles easily apply to implement a self-regulating heating system in contradistinction to the self-regulating cooling system described in detail herein before.  
         [0036]      FIG. 5  is a flow diagram illustrating a method  400  of cooling or heating sections or portions of a system or device according to one embodiment of the present invention. Method  400  is implemented by first providing a self-regulating cooling/heating system, as shown in block  402 ; and also providing as shown in block  404 , a system or device such as a radar display having sections or portions to be cooled or heated, and that is configured such that a coolant or heating medium can pass independently and freely through selected sections or portions of the system or device to be cooled or heated. The self-regulating cooling/heating system is then interfaced to the system or device sections or portions to be cooled/heated such that the flow rate of coolant or heating medium passing through each section is most preferably passively controlled in response to the temperature of the coolant or heating medium (fluidic medium) passing through the selected sections or portions of the self-regulating cooling/heating system and/or selected sections and/or portions of the system or device to be cooled/heated, as shown in block  406 .  
         [0037]     The self-regulating element, as stated herein before, may be implemented, for example by, but not limited to, a passively controlled variable orifice valve. The valve may include a thermal spring element immersed in the coolant or heating medium (fluidic medium) such that the thermal spring operates in response to a temperature differential to variably open and close the valve orifice to control the rate of coolant or heating medium passing through the valve. The self-regulating element can be placed within predetermined portions of the cooling/heating system itself, or alternatively, within predetermined portions of the system or device to be cooled/heated, such as discussed in detail herein before. As also stated herein before, the self-regulating element may optionally be an actively controlled element.  
         [0038]     Looking at  FIG. 6 , there is illustrated another application of a self-regulating element in a cooling/heating system according to one embodiment of the present invention. A manifold section  500  can be seen to employ a self-regulating element  502  having a thermal sensing spring  503  in one section of the manifold  500 ; while the plunger portion  504  of the self-regulating element  502  is positioned within a different section of the manifold  500 . Such a configuration is useful to control system or device temperatures in adjacent sections or portions of a system or device in certain applications that may require more stable overall environmental conditions to enhance operational stability.  
         [0039]      FIG. 7  illustrates a manifold portion  702  of a cooling/heating system  700  with an actively controlled self-regulating temperature sensing element  710  according to one embodiment of the present invention. The actively controlled self-regulating temperature sensing element  710  can be seen to have its thermal sensing wire  712  strategically positioned within a first manifold through port, while its associated plunger unit  714  is strategically positioned within a second manifold through port. It shall be understood that such active sensing element control can be applied to any embodiment described herein before in which only passive control principles were discussed. A computerized control unit  720  having requisite algorithmic software monitors a change in resistance of the thermal sensing wire  712  as fluidic medium passes over the thermal sensing wire  712 . A control signal from the computerized control unit  700  that is responsive to this change in resistance is sent to the plunger unit  714  to vary the movement of the plunger unit  714 . Movement of the plunger unit  714  then operates in response to this control signal to vary the amount of coolant or heating medium passing through the second manifold through port. This invention is not so limited however, and it shall be understood that the thermal sensing wire  712  and the plunger unit  714  can just as easily be positioned together within a single manifold through port, such as discussed herein before with reference to other particular embodiments of the present invention.  
         [0040]     In view of the above, it can be seen the present invention presents a significant advancement in the art of cooling and heating system techniques. Further, this invention has been described in considerable detail in order to provide those skilled in the heat transfer arts with the information needed to apply the novel principles and to construct and use such specialized components as are required. In view of the foregoing descriptions, it should be apparent that the present invention represents a significant departure from the prior art in construction and operation. However, while particular embodiments of the present invention have been described herein in detail, it is to be understood that various alterations, modifications and substitutions can be made therein without departing in any way from the spirit and scope of the present invention, as defined in the claims which follow. The cooling/heating system, for example, may employ any number of different manifold configurations, so long as cooling or heating for the system or device to be cooled or heated is self-regulating and passively or actively controlled in accordance with the principles described herein before. Further, the requisite self-regulating element(s) employed may be placed in any variety of appropriate locations to implement individual section cooling and/or heating to passively or actively achieve the desired self-regulating sectional cooling and/or heating in response to particular system or device cooling or heating medium temperature(s).