Cooling system for variable frequency drives

Abstract

A cooling system for a variable frequency drive (VFD) and / or an oil cooling device is disclosed. The cooling system includes a heat exchanger operatively connected to a cooling source component and the VFD. The cooling system includes a first coolant circuit routed through the heat exchanger and the VFD, and a second coolant circuit routed through the heat exchanger and the cooling source component. The cooling system includes a dual shaft pump connected to the first coolant circuit and / or the second coolant circuit and configured to circulate a first coolant through the first coolant circuit and a second coolant through the second coolant circuit for cooling the VFD. The first coolant circuit and / or the second coolant circuit includes a three-way valve and / or a thermostatic valve defining a bypass for the first coolant exiting the heat exchanger on the first coolant circuit or for the second coolant exiting or entering the heat exchanger on the second coolant circuit.

Description

[0001] Cross-references to related applications This application claims the benefit of U.S. Provisional Patent Application No. 63 / 774,283, filed March 19, 2025, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This subject matter relates to the field of refrigeration machines, and more particularly to a cooling system for a variable frequency drive (VFD) for a refrigeration machine. Summary of the Invention

[0003] This document describes a cooling system for a variable frequency drive (VFD). The cooling system includes a heat exchanger, a first coolant circuit guiding the heat exchanger and the VFD, and a second coolant circuit guiding the heat exchanger and cooling source components. Furthermore, the cooling system includes a dual-shaft pump connected to the first and second coolant circuits and configured to circulate the first coolant through the first coolant circuit and the second coolant through the second coolant circuit for cooling the VFD.

[0004] In one or more embodiments, the VFD includes a radiator configured to dissipate heat from the VFD to a first coolant in a first coolant circuit.

[0005] In one or more embodiments, the cooling system includes a thermostatic valve and a three-way valve that define a bypass on a first coolant circuit.

[0006] In one or more embodiments, the thermostatic valve and / or three-way valve are configured to divide the first coolant leaving the VFD into a first volume and a second volume, and to guide the first volume to the VFD via a bypass and the second volume to the VFD via a heat exchanger.

[0007] In one or more embodiments, the first volume is mixed with the second volume flowing through the heat exchanger at a thermostatic valve or three-way valve located downstream of the heat exchanger in the first coolant circuit.

[0008] In one or more embodiments, the cooling system further includes a sensor placed upstream of the VFD and connected to the thermostatic valve via a capillary connector, wherein the sensor is configured to actuate the thermostatic valve based on the temperature of a first coolant entering the VFD.

[0009] In one or more embodiments, the cooling system further includes a thermostatic valve and a three-way valve that define a bypass on a second coolant circuit.

[0010] In one or more embodiments, the thermostatic valve is located downstream of the VFD, and the three-way valve is located downstream of the heat exchanger, or vice versa.

[0011] In one or more embodiments, the cooling system also includes a sensor located upstream of the VFD and connected to the thermostatic valve via a capillary connector.

[0012] In one or more embodiments, the sensor is configured to actuate the thermostatic valve based on the temperature of the first coolant entering the VFD.

[0013] In one or more embodiments, the cooling system further includes a thermostatic valve and a three-way valve that define a bypass on a second coolant circuit.

[0014] In one or more embodiments, the thermostatic valve and / or three-way valve is located downstream of the cooling source component, and the three-way valve is located downstream of the heat exchanger, or vice versa.

[0015] In one or more embodiments, the cooling system further includes a sensor configured to actuate a thermostatic valve based on the temperature of a second coolant entering the heat exchanger.

[0016] In one or more embodiments, the sensor is positioned upstream of the heat exchanger in the second coolant circuit.

[0017] In one or more embodiments, the sensor is disposed on the first coolant circuit.

[0018] In one or more embodiments, the sensor is connected to the thermostatic valve via a capillary connector.

[0019] In one or more embodiments, the cooling system includes a sensor configured to determine the temperature of at least one of a first coolant or a second coolant.

[0020] In one or more embodiments, the cooling system further includes a pair of three-way valves that define a bypass on a first coolant circuit and / or a second coolant circuit, wherein the pair of three-way valves are configured to periodically open and / or close the connection to the bypass.

[0021] In one or more embodiments, the three-way valve is controlled based on the temperature of the first or second coolant determined by sensors placed on the first or second coolant circuit, respectively.

[0022] In one or more embodiments, the cooling source component includes a condenser or an evaporator.

[0023] In one or more embodiments, the second coolant includes condenser water or evaporator water.

[0024] In one or more embodiments, the cooling system further includes an oil circuit associated with an oil cooling device. The oil circuit is directed through a heat exchanger and connected to a biaxial pump, wherein the biaxial pump is configured to circulate oil through the oil circuit.

[0025] This document describes a cooling system for an oil cooling device. The cooling system includes a heat exchanger, an oil circuit guiding the heat exchanger and the oil cooling device, and a coolant circuit guiding the heat exchanger and cooling source components. Furthermore, the cooling system includes a dual-shaft pump connected to both the oil circuit and the coolant circuit, configured to circulate oil through the oil circuit and coolant through the coolant circuit.

[0026] This document describes a method for operating a cooling system for a VFD, the cooling system including a heat exchanger, a first coolant circuit, a second coolant circuit, and a biaxial pump connected to the first and second coolant circuits, and at least one valve defining a bypass on at least one of the first or second coolant circuits. The method includes: circulating a first coolant through the first coolant circuit and a second coolant through the second coolant circuit via the biaxial pump; determining the temperature of at least one of the first or second coolant downstream of at least one of the cooling source components of the heat exchanger or the second coolant circuit; and actuating the at least one valve based on the determined temperature.

[0027] The foregoing description of the invention is merely illustrative and is not intended to be limiting in any way. Other aspects, embodiments, features, and techniques disclosed herein will become more apparent from the following description taken in conjunction with the accompanying drawings, in addition to the illustrative aspects, embodiments, features, and techniques described above. Attached Figure Description

[0028] The accompanying drawings are included to provide a further understanding of the subject matter disclosure and are incorporated in and form a part of this specification. The drawings illustrate exemplary embodiments of the subject matter disclosure and, together with the description, serve to explain the principles of the subject matter disclosure.

[0029] In the accompanying drawings, similar parts and / or features may have the same reference numerals. Furthermore, various parts of the same type may be distinguished by adding a second reference numeral after the reference numeral to differentiate between similar parts. If only the first reference numeral is used in the description, the description applies to any of the similar parts having the same first reference numeral, regardless of the second reference numeral.

[0030] Figure 1A and Figure 1B An example block diagram of a refrigeration machine according to one or more embodiments disclosed in this subject matter is illustrated.

[0031] Figure 2A and Figure 2BThe diagrams illustrate circuit diagrams of cooling systems for variable frequency drives (VFDs) and oil cooling devices for refrigerators according to one or more embodiments disclosed in this subject matter.

[0032] Figure 3A and Figure 3B The illustration shows a circuit diagram of an exemplary cooling system having a bypass installed at a first coolant circuit, according to one or more embodiments disclosed in this subject matter.

[0033] Figure 4A and Figure 4B The illustration shows a circuit diagram of an example cooling system according to one or more embodiments disclosed in this subject matter, the cooling system having a bypass installed at a second coolant circuit, bypassing the cooling source component.

[0034] Figure 5A and Figure 5B The illustration shows a circuit diagram of an example cooling system according to one or more embodiments disclosed in this subject matter, the cooling system having a bypass installed at a second coolant circuit that bypasses the heat exchanger.

[0035] Figure 6 A flowchart illustrating a method of operating a cooling system according to one or more embodiments disclosed in this subject matter is shown. Detailed Implementation

[0036] The following is a detailed description of embodiments of the subject matter disclosed, as depicted in the accompanying drawings. The embodiments are so detailed that they clearly convey the subject matter disclosure. However, the amount of detail provided is not intended to limit contemplative variations of the embodiments; rather, it is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the subject matter disclosure as defined by the appended claims.

[0037] Various terms are used herein. Where a term used in the claims is not defined below, the broadest definition that has been given to the term by a person skilled in the art, as reflected in the printed publications and the published patent at the time of filing, shall be given.

[0038] In this specification, reference may be made to the spatial relationships between various components, as well as the spatial orientation of various aspects of the components of the device as depicted in the accompanying drawings. However, as those skilled in the art will recognize upon a full reading of this disclosure, the components described herein can be positioned in any desired orientation. Therefore, the use of terms such as “above,” “below,” “upper,” “lower,” “first,” “second,” or other similar terms to describe the spatial relationships between various components or the spatial orientation of aspects of such components should be understood as describing the relative relationships between components or the spatial orientation of aspects of such components, since the components described herein can be oriented in any desired direction.

[0039] Chillers employing variable frequency drives (VFDs) are critical components in systems and industries requiring precise and energy-efficient cooling. VFDs and other variable speed drive pumps are also desirable for customers to reduce energy consumption at the chiller level, for example, at the overall system level. These chillers are used in a wide range of applications, including but not limited to residential and commercial heating, ventilation, and air conditioning (HVAC) systems, data centers, refrigeration, and cooling systems.

[0040] In existing chillers, the VFD generates heat during operation. This generated heat is transferred from the VFD to the glycol loop / recycle, and from the glycol loop / recycle to the water loop / recycle via a heat exchanger. Additionally, water in the water loop / recycle then flows to the cooling source components to release heat from the glycol. Maintaining sufficient flow rates of both glycol and water in both the glycol and water loops is crucial for proper VFD cooling.

[0041] Insufficient condenser water flow prevents the heat exchanger from removing heat from the ethylene glycol, leading to overheating of the VFD. This limits the operating range and performance of the chiller, as its cooling efficiency is directly related to the customer's pump performance. Therefore, ineffective cooling results in VFD overheating, potentially causing failure or system shutdown. A solution is needed to address the challenges posed by existing cooling systems by providing a cooling system that prevents VFD overheating and effectively cools the VFD (or oil cooler) independently of other chiller operations, thereby improving the chiller's operating range and performance.

[0042] refer to Figure 1A and Figure 2A A refrigerator 10A with a variable frequency drive (VFD) 102 is disclosed. The refrigerator 10A may include a cooling system 100A for cooling the VFD 102 of the refrigerator 10A. The cooling system 100A may also include a cooling source component 106, which may be a condenser or an evaporator. The cooling source component 106 may be a source of "cold" fluid or water, i.e., configured to dissipate heat from a fluid (hereinafter referred to as a second coolant).

[0043] Furthermore, the cooling system 100A may include a first coolant circuit 108 guiding heat exchanger 104 and VFD 102, and a second coolant circuit 110 guiding heat exchanger 104 and cooling source component 106. The first coolant may circulate through the first coolant circuit 108, and the second coolant may circulate through the second coolant circuit 110. In one or more embodiments, the first coolant may be any fluid configured to absorb heat from VFD 102 and discharge heat to heat exchanger 104. Examples of the first coolant may include any one or combination of ethylene glycol, water, oil, etc., but are not limited thereto. Similarly, the second coolant may be any fluid configured to absorb heat from heat exchanger 104 and discharge heat to cooling source component 106. In one or more embodiments, the second coolant may include condenser water or evaporator water. The first coolant circuit 108 and the second coolant circuit 110 may be implemented as a set of pipes or channels forming corresponding closed loops for circulating the first and second coolants, respectively. The first coolant circuit 108 and the second coolant circuit 110 may include corresponding portions / locations through which heat can be absorbed or dissipated.

[0044] In one or more embodiments, VFD 102 may include or enclose a heat sink 101a (also referred to as VFD heat sink 101a). Heat sink 101a may include a brazed plate heat exchanger. In one or more embodiments, VFD 102 may be connected to heat sink 101a of cooling system 100A. In one or more embodiments, heat sink 101a may be configured to absorb heat within VFD 102 to prevent overheating of VFD 102. Heat sink 101a may also be configured to dissipate heat to another element, thereby allowing heat to escape from VFD 102. In one or more embodiments, a first coolant may enter VFD 102 and interact with heat sink 101a such that heat generated within VFD 102 may be absorbed by the first coolant via heat sink 101a. A first coolant circuit 108 (i.e., at some of its conduits) may be directed through heat sink 101a such that the first coolant flowing through the first coolant circuit 108 absorbs heat from heat sink 101a. The heat absorbed by the first coolant can then be discharged to the heat exchanger 104. In addition, the second coolant can absorb heat from the first coolant circuit 108 at the heat exchanger 104 and discharge the heat to the cooling source component 106.

[0045] Heat exchanger 104 may be configured to facilitate heat exchange between a first coolant and a second coolant. In one or more embodiments, the conduits of the first coolant circuit 108 and the second coolant circuit 110 may be placed adjacent to each other. The conduits may be thermally conductive to facilitate heat exchange between the coolants. In one or more embodiments, the conduits may be arranged such that the first coolant and the second coolant move relative to each other in opposite directions (i.e., in a counter-current arrangement). In other embodiments, the first coolant and the second coolant may move in the same direction. In one or more embodiments, the conduits of the second coolant circuit 110 may be arranged concentrically around the conduits of the first coolant circuit 108 to increase the surface area in heat exchanger 104 through which heat exchange may occur. In addition to providing cooling in cooling system 100A, the second coolant may also be used for other purposes, such as for direct refrigerant cooling of the housing.

[0046] Cooling system 100A may include a biaxial pump 112 connected to a first coolant circuit 108 and / or a second coolant circuit 110. The biaxial pump 112 may be configured to circulate a first coolant through the first coolant circuit 108 and a second coolant through the second coolant circuit 110 for cooling VFD 102. The biaxial pump 112 may include two shafts, which may be driven by a common drive mechanism (such as a motor). One shaft circulates the first coolant through the first coolant circuit 108, while the other shaft circulates the second coolant through the second coolant circuit 110, thereby allowing simultaneous operation / circulation through both the first coolant circuit 108 and the second coolant circuit 110. The biaxial pump 112 may operate simultaneously with the chiller 10A (or its pump). Furthermore, the use of the biaxial pump 112 allows for a reduction in the diameter of the pipes / channels forming the second coolant circuit 110. Reducing the diameter of the second coolant circuit 110 provides significant benefits, including cost savings, improved system efficiency, a compact design, and environmental advantages. These benefits make the cooling system 100A suitable for refrigeration units requiring optimal performance and reliability. It will be appreciated that the biaxial pump 112 described herein is merely exemplary, and any pump configuration allowing a single mechanical device to pump liquids in two or more separate loops is conceivable within the scope of this subject matter disclosure.

[0047] Both the first coolant circuit 108 and the second coolant circuit 110 can be directed through the heat exchanger 104. The first coolant can act as an intermediate cooling fluid in the first coolant circuit 108 and can flow through the VFD 102. The first coolant can absorb heat generated during the operation of the VFD 102. In one or more embodiments, the VFD 102 may include a VFD radiator 101a, which can be configured to facilitate the transfer of heat from the VFD 102 to the first coolant. The heated first coolant can be directed / flowed / pumped to the heat exchanger 104 by a biaxial pump 112, wherein the heated first coolant can release the absorbed heat to the second coolant in the second coolant circuit 110. Once the first coolant has been cooled in the heat exchanger 104, the cooled first coolant can be recirculated back to the VFD 102 by the biaxial pump 112 to continue absorbing heat from the VFD 102.

[0048] Furthermore, a second coolant (i.e., condenser water or evaporator water) can flow through heat exchanger 104 and biaxial pump 112 to absorb heat from the first coolant. After absorbing heat, the second coolant can be directed to cooling source component 106. At cooling source component 106, the heat gained by the second coolant can be dissipated into the cooling source component 106, and the cooled second coolant can return to heat exchanger 104 to repeat the process, thereby ensuring efficient cooling of VFD 102 by separating the internal heat transfer process (first coolant circuit) from the external heat dissipation process (second coolant circuit). This also prevents overheating of VFD 102 and maintains optimal operating conditions for VFD 102. Figures 2A to 5B In the diagram, dashed arrows indicate the flow of the first coolant, and solid lines indicate the flow of the second coolant.

[0049] In one or more embodiments, as an alternative or supplement to the first coolant circuit 108, other fluid circuits, such as... Figure 1B and Figure 2B As shown in the image.

[0050] refer to Figure 1B and Figure 2BThe diagram illustrates another refrigerator 10B with a separate cooling system 100B, which includes an oil cooling unit 103. While the refrigerator 10B may be substantially similar to the refrigerator 10A, the cooling system 100B of the refrigerator 10B may include an oil circuit 109 directed through the heat exchanger 104 and the oil cooling unit 103, instead of a first coolant circuit 108 directed through the VFD 102. Furthermore, a dual-shaft pump 112 of the refrigerator 10B may be connected to the oil circuit 109 to circulate oil through the oil circuit 109 and to circulate a second coolant through a second coolant circuit 110 for cooling the oil cooling unit 103. Additionally, in one or more embodiments, the oil cooling unit 103 may be integrated with a corresponding radiator (also referred to as an oil cooling unit radiator 101b). The oil cooling unit radiator 101b may be placed inside the oil cooling unit 103. The oil cooling unit may be configured to absorb heat generated within the oil cooling unit 103. Furthermore, the oil cooling device radiator 101b can transfer the absorbed heat to the oil circulating through the oil circuit 109, and the oil can then dissipate the heat to the heat exchanger 104. In the following text, the term "radiator 101" may be used together or separately to refer to radiators 101a and 101b.

[0051] In some cases, the temperature of the first coolant may approach or fall below the dew point, which can lead to condensation at VFD 102 and / or oil cooling unit 103. Condensation can be undesirable as it can be destructive and cause electrical problems. To prevent condensation, bypass lines may be provided in the first coolant circuit 108 / oil circuit 109 and / or the second coolant circuit 110, as per reference. Figures 3A to 5B As stated above.

[0052] refer to Figure 3A Cooling systems 100A and 100B (collectively referred to as cooling system 100) may include at least one three-way valve 114a and / or at least one thermostatic valve / three-way temperature-actuated regulating valve 114b in a first coolant circuit 108 / oil circuit 109. In one or more embodiments, the three-way valve 114a may be located downstream of heat exchanger 104, and the thermostatic valve 114b may be located upstream of heat exchanger 104. In one or more embodiments, the thermostatic valve 114b may be located downstream of VFD 102, and the three-way valve 114a may be located downstream of heat exchanger 104, or vice versa. The thermostatic valve 114b may be configured to open and / or close (and thereby allow or prevent the first coolant from circulating through it, respectively) at least one of valves 114a and 114b.

[0053] Three-way valve 114a and thermostatic valve 114b may define a bypass line / bypass 116a between them in the first coolant circuit 108, which allows at least a portion of the first coolant to flow / be directed (i.e., not flow through heat exchanger 104) around heat exchanger 104. In some embodiments, bypass 116a may be formed by a fluid connection (such as through a pipe or channel) between three-way valve 114a and thermostatic valve 114b. By integrating bypass 116a and valves 114a, 114b, cooling system 100 can improve flexibility, reliability, and efficiency in managing the temperature of the first coolant in the first coolant circuit 108.

[0054] Thermostatic valve 114b may be operably configured to divide the first coolant into one or more portions or volumes. In one or more embodiments, thermostatic valve 114b may be configured to divide the first coolant into a first volume to be directed from VFD 102 through bypass 116a and / or a second volume to be directed through heat exchanger 104, which is cooled by heat exchanger 104. A conventional three-way valve 114a may allow the first volume passing through and exiting bypass 116a and the second volume passing through and exiting heat exchanger 104 (or, in the case of refrigerator 10B, the first and second volumes of oil from oil cooling unit 103) to be mixed in or near three-way valve 114a in the first coolant circuit 108.

[0055] For example, a combined volume of the first coolant heated by radiators 101a or 101b (collectively referred to as radiator 101) can flow through the first coolant circuit 108. At the thermostatic valve 114b, the first coolant can be separated into a first volume (which can be directed / guided through bypass 116a) and a second volume (which can be directed / guided through heat exchanger 104). The first and second volumes can then be mixed at another valve 114a (or any other mixing point / joint where bypass 116a is reconnected to the first coolant circuit 108). Mixing can average the temperature of the first volume (which retains the heat absorbed from radiator 101) and the second volume (which may have dissipated heat through heat exchanger 104), so that the first coolant has a temperature above the dew point, thereby preventing condensation at VFD 102. It will be appreciated that the oil circuit 109 of the cooling system 100B can be suitably adapted to mix different volumes of oil to control its temperature and prevent condensation at the oil cooling device 103.

[0056] In one or more embodiments, the (temperature) sensor 118 may be placed on the first coolant circuit 108. In one or more embodiments, the sensor 118 may be placed downstream of the thermostatic valve / three-way temperature actuation valve 114b, or upstream of the radiator 101 / VFD 102, such as... Figure 3AAs illustrated in the figure. In one or more embodiments, sensor 118 may be a thermistor configured to determine the temperature of the mixed volume of the first coolant and transmit the determined temperature as an electrical signal via capillary connector 117, which may actuate a thermostatic valve / three-way temperature actuation valve 114b based on the temperature of the (mixed) first coolant upstream of radiator 101 / VFD 102. In one or more embodiments, thermostatic valve 114b may close when the temperature of the mixed first coolant exceeds a temperature threshold and may open when the temperature of the mixed first coolant is below another temperature threshold.

[0057] In other embodiments, sensor 118 (and / or a controller implementing thermostatic valve 114b actuated by sensor 118) may be configured to determine the temperature of the "mixed" first and second volumes and adjust the mixing of the first and second volumes to maintain a preset / desired temperature range. In one or more embodiments, three-way valve 114a and / or thermostatic valve 114b may include two input ports and one output port, or one input port and two output ports. The input and output ports may be opened or closed to allow the first coolant circuit to control the flow of the first coolant through it. For example, if sensor 118 / controller detects that the temperature of the first coolant is approaching the dew point, a signal from sensor 118 may cause thermostatic valve 114b to open bypass 116a, thereby allowing the first coolant to be divided into a first volume and a second volume and mixed to average (or increase) the temperature. In one or more embodiments, although the first and second volumes are mixed, the thermostatic valve 114b can close the connection toward the heat exchanger 104 as the temperature of the first coolant / oil continues to approach the dew point, thereby allowing the first coolant / oil to circulate in a closed loop through the radiator 101 and bypass 116a. In such an embodiment, the first coolant can continuously absorb heat from the radiator 101 until the temperature increases to a value within a desired temperature range to avoid condensation.

[0058] In one or more embodiments, if the temperature determined by sensor 118 exceeds a maximum or minimum limit or range for the second coolant entering heat exchanger 104 (at which point VFD 102 or oil cooling device 103 may become prone to overheating), sensor 118 may be configured to open or control (increase) the flow rate of the second volume toward heat exchanger 104. In some embodiments, sensor 118 may also send a control signal to close or control / limit the flow of the first volume through bypass 116a. The first coolant heated by radiator 101 may continue to circulate through heat exchanger 104 until the temperature of the first coolant drops to a value within a temperature range (i.e., below the maximum temperature limit).

[0059] In one or more embodiments, the three-way valve 114a and the thermostatic valve 114b (or a pair of three-way valves) may periodically open and / or close the connection to the bypass 116a and / or the heat exchanger 104 to control the mixing ratio of the first volume and the second volume to adjust the temperature of the first coolant / oil flowing through the radiator 101 corresponding to the VFD 102 / oil cooling device 103. In other embodiments, the thermostatic valve / three-way temperature-actuated regulating valve 114b may allow control of the flow rate of the first volume and / or the second volume.

[0060] Figure 3B This indicates an alternative cooling configuration in which the positions of the thermostatic valve / three-way temperature regulating valve 114b and the conventional three-way valve 114a can be switched, and the sensor 118 can be located near or embedded within the thermostatic valve / three-way temperature regulating valve 114b. In embodiments where the sensor 118 is integrated within the three-way temperature regulating valve 114b, the capillary connection 117 may not be required. Adjustment of the cooling path allows the cooling system 100 to respond efficiently to varying heat loads.

[0061] refer to Figure 4A and Figure 4B In one or more embodiments, with Figure 3A and Figure 3B In contrast to the embodiment shown, a three-way valve 114a and a thermostatic valve 114b may be disposed in the second coolant circuit 110. As shown, the cooling system 100 may include a radiator 101 (associated with a VFD 102 or an oil cooling device 103) configured to absorb heat from the VFD 102 or the oil cooling device 103 and discharge the heat to a first coolant circulating through the first coolant circuit 108. After absorbing heat from the radiator 101, the first coolant may circulate through a heat exchanger 104, where the absorbed heat may be discharged to a second coolant. The second coolant may absorb heat from the heat exchanger 104 and discharge the heat to a cooling source component 106. A biaxial pump 112 may be configured to circulate both the first coolant through the first coolant circuit 108 and the second coolant through the second coolant circuit 110.

[0062] As shown, a three-way valve 114a and a thermostatic valve 114b may define a bypass 116b in the second coolant circuit 110. In one or more embodiments, the thermostatic valve 114b and / or the three-way valve 114a may be located downstream of the cooling source component 106, and the three-way valve 114a may be located downstream of the heat exchanger 104, or vice versa. The bypass 116b may be configured to allow a first volume of the second coolant exiting the heat exchanger 104 (or heated by the heat exchanger 104) and a second volume of the second coolant cooled by the cooling source component 106 to be mixed in the thermostatic valve 114b. The thermostatic valve / three-way temperature-actuated regulating valve 114b in the second coolant circuit 110 may be configured to operatively open and / or close based on a determined temperature of the second coolant at the three-way valve (where the first and second volumes of the second coolant are mixed), as determined by the sensor 118 / controller (i.e., upstream of the heat exchanger 104 in the second coolant circuit 110), thereby regulating the rate of heat transfer between the first and second coolants in the heat exchanger 104. In one or more embodiments, the sensor 118 may be located upstream of the heat exchanger 104 in the second coolant circuit 110. The sensor 118 / controller may be configured to open or close the three-way temperature-actuated valve 114b using a capillary connection 117 between the sensor 118 / controller and the three-way temperature-actuated valve 114b. In embodiments where the sensor 118 / controller is embedded within the thermostatic valve / three-way temperature-actuated valve 114b, the capillary connection 117 may not be required. An embodiment where the three-way temperature regulating valve / thermostatic valve 114b is placed downstream of the cooling source component 106 (e.g.) Figure 4A The embodiment shown is a preferred embodiment.

[0063] In one or more embodiments, the three-way temperature regulating valve / thermostatic valve 114b may be placed upstream of the cooling source component 106, and the three-way valve 114a may be placed downstream of the cooling source component 106, such as... Figure 4B As shown in the diagram. In such an embodiment, the sensor 118 / controller may be placed downstream of the cooling source component 106 and may be connected to the thermostatic valve 114b via the capillary connector 117.

[0064] refer to Figure 5A In one or more embodiments, a three-way valve 114a and a thermostatic valve 114b may be provided in the second coolant circuit 110 to define a bypass 116c that bypasses the heat exchanger 104. The bypass 116c may allow heated second coolant leaving the heat exchanger 104 to mix with cooled second coolant from the cooling source component 106.

[0065] The second coolant can be cooled at the cooling source component 106 and circulates through the second coolant circuit 110. The second coolant circuit 110 is directed through the heat exchanger 104 to allow the "cooled" second coolant to absorb heat from the first coolant. The second coolant, now "heated," can then exit the heat exchanger 104.

[0066] Thermostatic valve 114b (e.g.) Figure 5A (As shown) can be configured to divide the heated second coolant leaving the heat exchanger 104 into a first volume and a second volume of heated second coolant. The first volume can be directly circulated / directed to the cooling source component 106, where heat from the first volume can be dissipated. The first volume can then be circulated / directed from the cooling source component 106 toward the heat exchanger 104. The second volume can be circulated / directed back upstream of the heat exchanger 104, thereby allowing the second volume of heated second coolant to mix with the cooled second coolant circulating from the cooling source component 106 to the heat exchanger 104. The mixing of the second volume and the cooled second coolant can average (or increase) the temperature of the second coolant entering the heat exchanger 104, thereby preventing condensation and / or scaling at the heat exchanger 104 and the radiator 101 (or its associated VFD 102 / oil cooling unit 103). Bypass 116c can be opened or closed based on the temperature sensed by sensor 118 at thermostatic valve 114b located downstream of heat exchanger 104 on second coolant circuit 110.

[0067] Sensor 118 / controller may be placed downstream of radiator 101 on the first coolant circuit 108 to determine the temperature of the first coolant leaving radiator 101. Based on the determined temperature, sensor 118 / controller may dynamically control the mixing of the first and second volumes to maintain a preset temperature by opening or closing thermostatic valve / three-way temperature regulating valve 114b, thereby ensuring that the mixed coolant entering heat exchanger 104 is within a desired temperature range. Sensor 118 / controller may be configured to control (i.e., open or close) thermostatic valve / three-way temperature regulating valve 114b using capillary connector 117 extending between sensor 118 / controller and thermostatic valve / three-way temperature regulating valve 114b.

[0068] Figure 5B This indicates the alternative configuration, where sensor 118 / controller, bypass 116c, and coolant flow direction are aligned with... Figure 5A Compared to different arrangements. In Figure 5BIn this embodiment, sensor 118 / controller can be repositioned to determine the temperature of the first coolant. In one or more embodiments, sensor 118 may be located on the first coolant circuit 108. Furthermore, thermostatic valve 114b may be located upstream of heat exchanger 104 on the second coolant circuit 110, and conventional three-way valve 114a may be located downstream of heat exchanger 104. Additionally, sensor 118 / controller may be located upstream of radiator 101 or downstream of heat exchanger 104 on the first coolant circuit 108. Thermostatic valve 114b may respond to sensor 118 / controller via capillary connector 117. If the temperature of the first coolant entering radiator 101 is below a threshold temperature, sensor 118 / controller may transmit a signal through capillary connector 117 to actuate thermostatic valve 114b, diverting the second coolant entering thermostatic valve 114b to bypass 116c and heat exchanger 104. The second coolant can be divided into a first volume and a second volume, with the first volume directed to the cooling source component 106 via bypass 116c and the second volume directed to the heat exchanger 104. Similarly, if the temperature of the first coolant entering the radiator 101 is greater than another threshold temperature, the sensor 118 / controller 300 can transmit a signal via capillary connector 117 to the thermostatic valve 114b to shut off the second coolant entering the bypass 116c, thereby causing all the second coolant leaving the thermostatic valve 114b to be diverted to the heat exchanger 104.

[0069] To further improve the efficiency of the cooling system 100 and prevent operational problems caused by condensation, a three-way valve 114a and a thermostatic valve 114b may be integrated into the first coolant circuit 108 and / or the second coolant circuit 110. As an alternative or supplement to the valves located in the first coolant circuit 108, the three-way valve 114a and the thermostatic valve 114b may, for example, ensure that the temperature of the first coolant is maintained above the dew point by mixing a first volume of the first coolant heated by the radiator 101 and a second volume cooled by the heat exchanger 104. Maintaining the temperature of the first and / or second coolant prevents condensation on the VFD 102 / oil cooling unit 103, thereby ensuring consistent performance and reducing the maintenance requirements of the refrigeration units 10A / 10B.

[0070] While some embodiments have been shown with different locations / arrangements for the sensor 118 / controller, three-way valve 114a and thermostatic valve 114b, bypass (116a, 116b, 116c) and capillary connection 117, it will be appreciated that the cooling system 100 may be suitably adapted to any other arrangement having the foregoing components without departing from the scope of this subject matter disclosure.

[0071] Therefore, by implementing different cooling configurations, the cooling system 100 can provide flexibility in thermal management strategies, improve heat dissipation efficiency, thereby preventing overheating and ensuring stable operation of the VFD 102 (or other oil cooling device 103), and optimize the interaction between the first coolant and the second coolant, thereby ensuring effective heat removal and temperature regulation.

[0072] Therefore, this subject matter disclosure (i.e., cooling system 100) overcomes the disadvantages, limitations, and deficiencies associated with existing cooling systems by providing an improved and efficient solution that reduces reliance on external pumps, and prevents problems such as scaling and condensation in heat exchanger 104 or any associated components, resulting in improved performance and lower maintenance costs. The tandem pump 112 employed in the second coolant circuit 110 of cooling system 100 ensures consistent second coolant flow. The tandem pump 112 can be dynamically adjusted to overcome pressure drops in the second coolant circuit 110, thereby ensuring stable flow through it. The tandem pump 112 allows cooling system 100 to operate independently, ensuring uninterrupted cooling of VFD 102, thereby extending the operating range of chillers 10A / 10B. The tandem pump 112 optimizes the flow rate and pressure of the first and second coolants through their respective circuits or bypasses, thereby reducing energy consumption during low-load conditions. Furthermore, using a dual-shaft pump 112 in the cooling system 100 reduces labor (i.e., for installation and maintenance) and component costs because both shafts of the dual-shaft pump 112 can be driven by the same motor (or drive mechanism). Using a single drive mechanism for both shafts means that the dual-shaft pump 112 may require less installation space compared to two separate pumps, making it ideal for compact refrigeration unit designs where space is limited. Additionally, a single dual-shaft pump 112 handling both the first coolant circuit 108 and the second coolant circuit 110 simplifies the construction of the cooling system 100, thereby reducing the potential downtime and maintenance complexity associated with managing multiple pumps.

[0073] While various embodiments of the subject matter disclosed herein have been described for the purposes of simplification and better explanation, for cooling systems including a first coolant circuit and a second coolant circuit for cooling a VFD, the teachings of the subject matter disclosure are equally applicable to other cooling systems having an oil circuit and a second coolant circuit, or a first coolant circuit, an oil circuit and a second coolant circuit for cooling an oil cooling device, and all such embodiments are within the scope of the subject matter disclosure.

[0074] Figure 6A flowchart illustrating a method 600 for operating a cooling system for a variable frequency drive (VFD) according to one or more embodiments disclosed in this subject matter is shown. Although method 600 is described in the context of VFD 102, it will be appreciated that method 600 can be suitably adapted for use with oil cooling device 103 and oil circuit 109 (e.g., Figure 2B (as shown in the image).

[0075] At step 602, method 600 may include circulating a first coolant through a first coolant circuit 108 and a second coolant through a second coolant circuit 110 via a dual-shaft pump 112. In one or more embodiments, step 602 may include simultaneously driving the first and second shafts of the dual-shaft pump 112 via a common motor or drive mechanism. By circulating both coolants simultaneously, cooling system 100 ensures that heat absorbed by the first coolant at VFD 102 is continuously transferred to the second coolant at heat exchanger 104. In embodiments utilizing oil cooling device 103, step 602 may include circulating oil through oil circuit 109 via the first shaft while simultaneously circulating condenser / evaporator water through the second coolant circuit 110 via the second shaft. Simultaneous circulation reduces the need for multiple pumps and simplifies the control logic required to start cooling.

[0076] At step 604, method 600 may include determining the temperature of at least one of a first or second coolant downstream of at least one of the heat exchanger 104 or cooling source component 106 in the second coolant circuit 110. In one or more embodiments, the temperature may be determined by a sensor 118 (e.g., a thermistor or temperature probe). In one or more embodiments, the temperature may be determined downstream of at least one of the heat exchanger 104 or cooling source component 106 in the second coolant circuit 110 because they correspond to mixing points where the treated volume of the coolant (e.g., the volume cooled by the heat exchanger 104 or cooling source component 106) and the bypass volume of the coolant (e.g., the volume directed through bypasses 116a, 116b, or 116c without heat treatment) may be combined. Measuring the temperature at such mixing points allows the sensor 118 to determine the resulting temperature of the mixed coolant, thereby ensuring that the first / second coolant delivered to VFD 102 or heat exchanger 104 is above the corresponding dew point to prevent condensation. For example, when using bypass 116a (as in... Figure 3A In the embodiment of the bypass connection, the temperature can be determined downstream to assess whether the mixture of hot first coolant (from VFD 102) and cold first coolant (from heat exchanger 104) is warm enough to avoid condensation on VFD 102. Similarly, in embodiments utilizing bypass 116c (as in... Figure 5A(In the middle), the temperature can be determined downstream of the heat exchanger 104 to regulate the mixture of heated and cooled second coolant.

[0077] At step 606, method 600 may include actuating at least one valve based on a determined temperature. In such embodiments, method 600 may include a controller or capillary connection 117 physically actuating at least one valve (such as either a thermostatic valve 114b or a three-way valve 114a defining a bypass) to regulate the bypass flow. In one or more embodiments, actuating the valve may result in splitting the flow of the first / second coolant into a first volume directed through the bypass (e.g., 116a, 116b, or 116c) and a second volume directed through the heat exchanger 104 (or cooling source component 106). For example, if the temperature determined at step 604 indicates that the first coolant is approaching its dew point, the valve may be actuated to increase the flow through the first volume of bypass 116a, thereby recirculating heat from VFD 102 to raise the loop temperature. Conversely, if the temperature indicates overheating / fouling, the valve may be actuated to close the bypass and direct maximum flow through the heat exchanger 104. Regarding the second coolant loop 110 (e.g., Figure 5A In one embodiment, the actuation valve can direct a second coolant around the heat exchanger 104 to prevent overcooling or scaling.

[0078] While this subject matter disclosure has been described with reference to exemplary embodiments, those skilled in the art will understand that various changes may be made and equivalents may be substituted for elements therein without departing from the scope of the subject matter disclosure as defined by the appended claims. Modifications may be made to adapt particular situations or materials to the teachings of this subject matter disclosure without departing from the scope of the subject matter disclosure. Therefore, it is intended that this subject matter disclosure is not limited to the specific embodiments disclosed, but rather that it includes all embodiments falling within the scope of the subject matter disclosure as defined by the appended claims.

[0079] In interpreting the specification, all terms should be interpreted as broadly as possible, consistent with the context. In particular, the terms "comprising" and "including" should be interpreted as referring to an element, component, or step in a non-exclusive manner, indicating that the referenced element, component, or step may be present, utilized, or combined with other elements, components, or steps not explicitly referenced. Where the claims in the specification relate to at least one element selected from the group consisting of A, B, C, ..., and N, the text should be interpreted as requiring only one element from that group, rather than A plus N or B plus N, etc.

Claims

1. A cooling system for a variable frequency drive (VFD), the cooling system comprising: Heat exchanger; A first coolant circuit is guided through the heat exchanger and the VFD; A second coolant circuit is guided through the heat exchanger and cooling source components; as well as A dual-shaft pump is connected to the first coolant circuit and the second coolant circuit, and is configured to circulate a first coolant through the first coolant circuit and a second coolant through the second coolant circuit for cooling the VFD.

2. The cooling system according to claim 1, wherein, The VFD includes a radiator configured to dissipate heat from the VFD to the first coolant in the first coolant circuit.

3. The cooling system according to claim 1 further includes a thermostatic valve and a three-way valve that define a bypass on the first coolant circuit.

4. The cooling system according to claim 3, wherein, The thermostatic valve is located downstream of the VFD, and the three-way valve is located downstream of the heat exchanger, or vice versa.

5. The cooling system of claim 3 further includes a sensor positioned upstream of the VFD and connected to the thermostatic valve via a capillary connector.

6. The cooling system according to claim 5, wherein, The sensor is configured to actuate the thermostatic valve based on the temperature of the first coolant entering the VFD.

7. The cooling system of claim 1 further includes a thermostatic valve and a three-way valve that define a bypass on the second coolant circuit.

8. The cooling system according to claim 7, wherein, The thermostatic valve and / or the three-way valve are located downstream of the cooling source component, and the three-way valve is located downstream of the heat exchanger, or vice versa.

9. The cooling system of claim 7 further includes a sensor configured to actuate the thermostatic valve based on the temperature of the second coolant entering the heat exchanger.

10. The cooling system according to claim 9, wherein, The sensor is located upstream of the heat exchanger in the second coolant circuit.

11. The cooling system according to claim 9, wherein, The sensor is installed on the first coolant circuit.

12. The cooling system according to claim 9, wherein, The sensor is connected to the thermostatic valve via a capillary connector.

13. The cooling system according to claim 9, wherein, The sensor is configured to determine the temperature of at least one of the first coolant or the second coolant.

14. The cooling system of claim 1, further comprising a pair of three-way valves defining a bypass on the first coolant circuit and / or the second coolant circuit, wherein, The pair of three-way valves are configured to periodically open and / or close the connection to the bypass.

15. The cooling system according to claim 14, wherein, The pair of three-way valves are controlled based on the temperature of the first coolant or the second coolant, determined by sensors placed on the first coolant circuit or the second coolant circuit, respectively.

16. The cooling system according to claim 1, wherein, The cooling source components include a condenser or an evaporator.

17. The cooling system according to claim 1, wherein, The second coolant includes condenser water or evaporator water.

18. The cooling system of claim 1, further comprising an oil circuit associated with the oil cooling device, wherein, The oil circuit is directed through the heat exchanger and connected to the biaxial pump, wherein the biaxial pump is configured to circulate oil through the oil circuit.

19. A cooling system for an oil cooling device, comprising: Heat exchanger; An oil circuit, which is guided through the heat exchanger and the oil cooling device; A coolant circuit, which is guided through the heat exchanger and cooling source components; as well as A twin-shaft pump connected to at least one of the oil circuit and the coolant circuit, and configured to circulate oil through the oil circuit and coolant through the coolant circuit.

20. A method of operating a cooling system for a variable frequency drive (VFD), the cooling system comprising a heat exchanger, a first coolant circuit, a second coolant circuit, and a biaxial pump connected to the first coolant circuit and the second coolant circuit, and at least one valve defining a bypass on at least one of the first coolant circuit or the second coolant circuit, wherein, The method includes: The biaxial pump circulates a first coolant through the first coolant circuit and a second coolant through the second coolant circuit. Determine the temperature of at least one of the first or second coolants downstream of at least one of the cooling source components in the heat exchanger or the second coolant circuit; and The at least one valve is actuated based on the determined temperature.

Images