Patent Publication Number: US-2012036874-A1

Title: Active cooling of a compressor in an appliance

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application relates to U.S. patent application Ser. No. ______, filed on ______, entitled “EVAPORATIVE COOLING CONDENSER FOR HOUSEHOLD APPLIANCE”, GE Docket No. 242918. 
    
    
     BACKGROUND 
     The present disclosure generally relates to appliances, and more particularly to active cooling of a compressor in a refrigeration appliance. 
     Government regulations and consumer demand strongly encourage the development of low energy use appliances. Cooling and air-conditioning systems for appliances such as refrigerators consume a great deal of energy. Efforts to produce highly efficient appliances can be costly. For example, various approaches to energy-saving appliances have been developed that include the use of vacuum panels to decrease the amount of heat entering the refrigerator from the external environment. However, the use of vacuum panels requires the addition of expensive parts and increases the total cost of the appliance for the consumer. 
     The compressor in an appliance such as a refrigerator typically generates a significant amount of heat during operation. Generally, attempts to cool the compressor utilize air. Typically, fans are used to move air through the condenser then also to the compressor. Thus, the air reaches the compressor it is already warmed or at a temperature above the ambient temperature, and the cooling capacity is limited. It is estimated that with proper cooling, the energy efficiency rating (“EER”) of a compressor might be improved by approximately 3.5%. 
     Accordingly, it would be desirable to provide a system that addresses at least some of the problems identified. 
     BRIEF DESCRIPTION OF THE EMBODIMENTS 
     As described herein, the exemplary embodiments overcome one or more of the above or other disadvantages known in the art. 
     One aspect of the exemplary embodiments relates to a system for cooling a compressor for a household appliance. In one embodiment, the system includes a water source, a compressor having an outer shell, where the compressor is configured to compress a refrigerant during a cooling cycle of the appliance, and a fluid heat transfer device, the fluid heat transfer device being configured to receive water from the water source and apply the water to the outer shell for rejecting heat from the compressor. 
     In another aspect, the disclosed embodiments are directed to a method. In one embodiment, the method includes detecting an operation of a compressor in a refrigerant-based cooling appliance, and applying water to an external surface of the compressor at a rate configured to enhance an evaporation of the water and enable the compressor to reject heat. 
     In a further aspect, the disclosed embodiments are directed to a cooling system for a household appliance. In one embodiment, the cooling system comprises an evaporator, a compressor coupled to the evaporator stage, a condenser, the condenser being located after the compressor stage and before the evaporator stage, and a fluid heat transfer device configured to apply water to an external surface of the compressor to cause the compressor to reject heat when the compressor is operating. 
     These and other aspects and advantages of the exemplary embodiments will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. Moreover, the drawings are not necessarily drawn to scale and that, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein. In addition, any suitable size, shape or type of elements or materials could be used. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an exemplary appliance incorporating aspects of the disclosed embodiments. 
         FIG. 2  is a schematic block diagram of one embodiment of a compressor cooling system incorporating aspects of the present disclosure. 
         FIG. 3  is a schematic block diagram of an exemplary compressor cooling system incorporating aspects of the disclosed embodiments. 
         FIG. 4  illustrates an exemplary pattern for an outer casing of a compressor incorporating aspects of the disclosed embodiments. 
         FIG. 5  illustrates a schematic block diagram of compressor cooling system incorporating aspects of the disclosed embodiments. 
     
    
    
     DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS 
     Referring to  FIG. 1 , an exemplary household appliance, such as a refrigerator, incorporating aspects of the disclosed embodiments, is generally designated by reference numeral  100 . The aspects of the disclosed embodiments are generally directed to a compressor cooling system for a refrigeration appliance such as a refrigerator. Lowering the temperature of the compressor in a refrigerator can lead to improved performance and efficiency of a compressor in a refrigerant based cooling system. By improving the efficiency, certain benefits and advantages can be realized, such as energy and cost savings. Although the aspects of the disclosed embodiments will generally be described with a respect to a household appliance such as a refrigerator, in alternate embodiments the aspects of the present disclosure can be generally applied to any appliance that includes a refrigerant based cooling system, such as for example, a freezer or air conditioning unit. 
     The exemplary refrigerator  100  shown in  FIG. 1  is a multi-compartment refrigerator that includes at least two compartments  104 ,  106  within a cabinet structure  102 . In the embodiment shown in  FIG. 1 , the compartment  104  comprises a fresh food compartment, while the compartment  106  comprises a freezer compartment. In alternate embodiments, the refrigerator  100  of the present disclosure can include any suitable number of compartments configured in any suitable manner. The refrigerator  100  includes French style doors  108  and  110  for the fresh food compartment  104 , and door or drawer  112  for the freezer compartment  106 . A divider or mullion  114  separates the fresh food compartment  104  from the freezer compartment  106 . In alternate embodiments, the refrigerator  100  can include any suitably styled doors for the refrigerator compartments  104 ,  106 . 
       FIG. 2  illustrates one embodiment of a cooling system  200  for the refrigerator  100  incorporating aspects of the disclosed embodiments. In one embodiment, the cooling system  200  includes a compressor  202 , a condenser  204 , an evaporator  206  and a fluid heat transfer device  210 . 
     The compressor  202  is generally configured to compress a low or ambient temperature and low-pressure refrigerant received from the evaporator  206  into a high-temperature and high-pressure gaseous refrigerant. In the example shown in  FIG. 2 , the condenser  204  is connected to the compressor  202  and is configured to condense the compressed gaseous refrigerant into a liquid refrigerant. The evaporator  206  is connected between the condenser  204  and the compressor  202  and, is generally configured to evaporate the expanded refrigerant, absorb heat and generate cool air. Each of the compressor  202 , the condenser  204  and evaporator  206  can be configured in any suitable manner and include other components and connections for providing the general functionalities associated with a refrigerant based cooling system. 
     The aspects of the disclosed embodiments are generally directed to compressor cooling system that is configured to lower the temperature of the compressor  202  in the refrigerant based cooling system  200 . When the compressor  202  is running, the compressor  202  generates heat. It is desirable to reduce the operational temperature of the compressor  202  and improve, among other things, the energy efficiency of the compressor  202 . In the embodiment shown in  FIG. 2 , the fluid heat transfer device  210  is generally configured to lower the temperature of the compressor  202  by wetting the compressor  202  with a fluid such as water or water vapor, generally referred to herein as “water.” A heat convection process causes the compressor  202  to reject heat to the water, thus lowering the temperature of the compressor  202 . 
     As is shown for example in  FIG. 3 , the compressor  202  includes an outer casing, outer shell or shear  302 . The outer casing  302  generally surrounds the working components of the compressor  202 . In one embodiment, the outer casing  302  of the compressor  202  is formed or made from a material that is thermally conductive, such as metal or steel, for example. When the compressor  202  is running, the heat that is generated from the working components inside the compressor  202 , as well as the heat from the refrigerant operated on within the compressor  202 , is generally transferred to the outer casing  302 . The heat can then be rejected to the ambient air outside the outer casing  302 . However, the amount of heat that can typically be rejected to the ambient air by this process is limited. 
     In one embodiment, referring to  FIG. 3 , the fluid heat transfer device  210  is configured to wet the outer casing  302  of the compressor  202  with water by applying water to the outer casing  302  in the form of water drops or a spray. As is shown in  FIG. 3 , in one embodiment, to apply the water in the form of water drops, water drop applicator  304  can be used. To apply the water in the form of a spray or mist, water spray applicator  306  is used. In alternate embodiments, any suitable applicator can be used to apply the water to the outer casing  302  of the compressor  202  in the desired form. 
     Referring to  FIG. 3 , the water used for application to the outer case  302  of the compressor  202  can be delivered or supplied from one or both of a primary water source  316  as well as a secondary water source  318 . In one embodiment, the primary water source  316  generally comprises a main water supply, such as that used to supply the water dispensing device  310  or ice maker  308  of the refrigerator  100 . The secondary water source  318  generally comprises recycled water that is formed as a byproduct of the operation of the refrigerator  100 . For example, defrost drain water that is generated as a result of a defrosting cycle or process in the cooling system  200  can be collected to make up the secondary water source  318 . Alternatively, or in addition to, other water or condensation that may form on the interior or exterior surfaces of the cabinet structure  102  can be collected and used to form the secondary water source  318 . The use of the secondary water  318  can allow water to be supplied for cooling the compressor  202  in a practical and energy efficient manner. 
     The flow of water from the primary and secondary sources  316 ,  318  to each of the applicators  304 ,  306  can generally be controlled by the use of one or more valves, such as valves  321 - 325  shown in  FIG. 3 . Each of the primary and secondary source  316 ,  318  can be suitably coupled to the fluid heat transfer device  210  by tubing  320  and the valves  321 - 325 , where each source  316 ,  318  can be individually controlled to provide an appropriate supply of water to the fluid heat transfer device  210 . In one embodiment, referring to  FIG. 2 , the controller  216  can determine and control the opening and closing of each water valve  321 - 325  for supplying water to the fluid heat transfer device  210 . For example, where only water from the primary water source  316  is being utilized, valves  322  and  323  are open, while valve  321  is closed. When the secondary water source  318  is the only utilized fluid source, valve  322  remains closed, while valves  321  and  323  are opened. The aspects of the disclosed embodiments can also utilize a mix of the primary and secondary water sources  316 ,  318 . In this embodiment, one or more of the valves  321 - 323  can be partially opened or closed to regulate the flow of water from each of the sources  316 ,  318 , as desired. In one embodiment, one of the water valves, such as water valve  323 , can also include a pump, or other such water regulator, that is configured to adjust the fluid application rate as is otherwise described herein. 
     In one embodiment, the control of the water valves  321 - 323  for feeding the fluid heat transfer device  210  can also be correlated to the operational cycles of the compressor  202 . In one embodiment, when the compressor  202  is ON, the water valves  321 - 323  will be enabled to be opened or open. When the compressor  202  is OFF, the water valves  321 - 323  can be disabled, or kept closed. 
     Generally, the amount of water that is used to wet the outer casing  302  will be controlled so that there is a minimal amount of accumulation of excess water in or around the area beneath the compressor  202 . In one embodiment, the rate of application of the water or water vapor to the outer casing  302  will generally be a function of the evaporation rate of the water. An approximate temperature of the external surfaces of the outer casing  302  when the compressor is running will be known or can be determined. Based on this temperature, an evaporation rate of the water can be calculated. Generally, the water application rate is equal to or less than the evaporation rate of the water. In one embodiment, the ambient temperature and/or the relative humidity level can also be determined and factored into the calculation of the water evaporation rate. 
     As is shown in  FIG. 2 , in one embodiment, the cooling system  200  can also include a temperature sensor  214 . The temperature sensor  214  can be configured to monitor one or more of the ambient temperature, or the temperature of the system components such as the compressor  202  or the condenser  204 . The temperature sensor  214  can be any suitable temperature sensing device, such as a thermocouple, for example, and can comprise a stand-alone device or be integrated as part of the controller  216 , for example. In one embodiment, the temperature sensor  214  can provide temperature indications to the controller  216 , where the controller  216  can interpret the data for the purpose of determining whether or not to activate the fluid heat transfer device  210  or to adjust the fluid application rate. For example, if the ambient temperature or the temperature of the outer casing  302  of the compressor  202  is not high enough to provide adequate evaporation of the water, the controller  216  can interrupt, adjust or disable the operation of the fluid heat transfer device  210 . As the ambient temperature, or the temperature of the outer casing  302  increases, the fluid application rate can be correspondingly increased. 
     As is also shown in  FIG. 2 , in one embodiment, the system  200  includes a humidity sensor  212 . The humidity sensor  212  can be integrated into the system  200  or a stand-alone device. The humidity sensor  212  is generally configured to detect a humidity level in and around the appliance  100 , and in particular in the area of the compressor  202 . The determined humidity level can then be used by the controller  216  to control the water application rate so that most, if not all of the water applied to the outer casing  302  will evaporate. For example, in periods of high humidity, the water application rate can be set to a rate that is lower than the water application rate that is used in drier periods. In one embodiment, the determined humidity level can also be used to control the activation of the fluid heat transfer device  210 . If the humidity level is too high, it may not be desirable to introduce or apply any water to the compressor  202 . In one embodiment, a signal corresponding to the detected humidity level is sent to the controller  216 , where the controller  216  is configured to enable or disable the fluid heat transfer device  210 . The aspects of the disclosed embodiments are generally applicable in environments where the relative humidity levels are below pre-determined values, such as for example, approximately 40-50% relative humidity, and are less effective at humidity levels that are higher than approximately 70%. The ranges disclosed herein are merely exemplary and any suitable relative humidity level can be used. 
     Generally, the external surface  330  of the outer casing  302  of the compressor  202  is relatively smooth, and any water that is applied to the external surface  330  will have a tendency to run over and off of the external surface  330  in an arbitrary manner. In one embodiment, referring to  FIG. 4 , the external surface or surfaces  330  can be configured to include a pattern  402 . The pattern  402  is generally configured to enhance heat exchange and water evaporation.  FIG. 4  illustrates an exemplary pattern  402  that can be used in conjunction with the aspects of the disclosed embodiments. The pattern  402  can be patterned or molded with one or more grooves  404 . The pattern  402  or grooves  404  are generally configured to more evenly spread and distribute the water, such as water drop  406 , over the external surfaces  330  to enhance the heat exchange and evaporate. As is shown in  FIG. 4 , pattern  402  will cause the water drop  406  to separate into one or more parts and travel in the direction A, as indicated by the arrows. In one embodiment, the pattern  402  is in the form of grooves that can be stamped or molded into the external surfaces  330 . In alternate embodiments, the pattern  402  can include any suitable pattern, including for example, a double spiral or quad-spiral pattern. 
     As noted above, in one embodiment, a pan or container  314  can be used to collect water than runs off of the external surface  330  of the compressor  202 . In one embodiment, the pan  314  can include or be coupled to a water level sensor  326 . The water level sensor  326  can monitor a water level in the pan  314 . If the water level gets to high, the fluid heat transfer device  210  can be disabled, or the flow of water to the fluid heat transfer device  210  can be stopped. In one embodiment, the water level sensor  326  can comprise a float mechanism. In alternate embodiments, the water level sensor  326  can comprise any suitable water level sensor, other than including a float. In one embodiment, any water collected in the pan  314  can be fed back to the fluid heat transfer device  210  through the secondary water source  318 . In this manner, any runoff water is recycled. 
     In one embodiment, referring to  FIG. 5 , the evaporation rate of the water and cooling effect on the compressor  202  can be enhanced by the use of a fan  502  to move air over and around the compressor  220 , when the outer surface  302  are in the wetted state. When the outer casing  302  of the compressor  202  is wetted by the fluid heat transfer device  210 , the evaporation removes heat from the outer casing  302  of the compressor  202 . The temperature of the outer casing  302 , and thus the temperature of the compressor  202 , will be lowered by rejecting heat to this water. In the embodiment shown in  FIG. 5 , the fan  502  is positioned to pull air in the direction F 1  over and around the compressor  202 . In an alternate embodiment, the fan  502  can be position so as to push a flow of air around and over the outer casing  302 . For example, in one embodiment, the fan  502  comprises the fan used to move air through the condenser  204  in a manner generally understood. One example of such a fan configuration is described in U.S. patent application Ser. No. ______ (GE Docket No. 242918), the disclosure of which is incorporated herein by reference in its entirety. In this embodiment, the airflow path F 1  generally comprises the airflow path created by the condenser fan. In alternate embodiments, the airflow path can be any suitable airflow that will enhance the evaporation of the water applied to the outer casing  302  of the compressor  220 . 
     The aspects of the disclosed embodiments may also include software and computer programs incorporating the process steps and instructions described above that are executed in one or more computers. In one embodiment, one or more computing devices, such as a computer or controller  216  of  FIG. 2 , are generally adapted to utilize program storage devices embodying machine-readable program source code, which is adapted to cause the computing devices to perform the method steps of the present disclosure. The program storage devices incorporating features of the present disclosure may be devised, made and used as a component of a machine utilizing optics, magnetic properties and/or electronics to perform the procedures and methods of the present disclosure. In alternate embodiments, the program storage devices may include magnetic media such as a diskette or computer hard drive, which is readable and executable by a computer. In other alternate embodiments, the program storage devices could include optical disks, read-only-memory (“ROM”) floppy disks and semiconductor materials and chips. 
     The computing devices may also include one or more processors or microprocessors for executing stored programs. The computing device may include a data storage device for the storage of information and data. The computer program or software incorporating the processes and method steps incorporating features of the present disclosure may be stored in one or more computers on an otherwise conventional program storage device. 
     The aspects of the disclosed embodiments are generally directed to cooling a compressor of a refrigerant based cooling system in a household appliance. A fluid in the form of water or water vapor is applied to the external surfaces or outer casing of the compressor to enhance a heat exchange between the compressor and the ambient air. The fluid is applied in the form of droplets or a spray, and is typically applied at a rate that is equal to or slightly below the evaporation rate of the water. The source of the water that is applied to the compressor can come one or both of a main water supply or a recycled water supply, where the recycled water supply is formed as a byproduct of the operation of the refrigerator as well as any runoff from the application of the water to the compressor. Decreasing the temperature of the compressor in a refrigerator can generally improve the compressor efficiency and lead to certain benefits and advantages, such as energy and cost savings. 
     Thus, while there have been shown and described and pointed out fundamental novel features of the invention as applied to the exemplary embodiments thereof, it will be understood that various omissions and substitutions and changes in the form and details of devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.