Refrigerator operation system for energy storage system battery and operation method thereof

Abstract

The invention relates to a refrigerator operation system for an energy storage system battery and an operation method thereof. The refrigerator operation system comprises the energy storage system battery; a battery control unit for controlling charging and discharging of the energy storage system battery; the refrigerator unit is used for cooling the energy storage system battery according to a cooling control signal in the charging and discharging process of the energy storage system battery; and a cooling control unit that performs heat generation management by providing the cooling control signal during charging and discharging of the energy storage system battery by communicating with the battery control unit, wherein the cooling control signal is provided to the refrigerator unit when at least one of a cooling start signal of the battery control unit is input and a preset refrigerator temperature condition is satisfied; therefore, heating management can be actively executed according to the charging and discharging environment of the energy storage system battery, and the charging efficiency of the energy storage system battery is improved.

Description

Technical Field

[0001] This invention relates to a cooling system and its operating method for an energy storage system (ESS) battery that, through communication with a battery control unit, performs heat management by providing a cooling control signal from a cooling control unit during the charging and discharging process of the ESS battery. Furthermore, it relates to a system that, upon receiving a cooling start signal input from the battery control unit and meeting at least one of pre-set cooler temperature conditions, actively performs heat management based on the charging and discharging environment of the ESS battery by providing a cooling control signal to the cooler unit, thereby improving the charging efficiency of the ESS battery. Background Technology

[0002] As is well known, for energy storage system (ESS) batteries that can be charged and discharged in environmentally friendly vehicles, including electric vehicles and hybrid vehicles, a system is needed to manage the temperature of the energy storage system (ESS) batteries in order to maintain a target temperature (e.g., 20-30°C for lithium-ion batteries) independent of the surrounding environment and thereby maintain optimal performance and efficiency.

[0003] The system described above can delay the temperature rise of the energy storage system (ESS) battery when the battery modules, arranged in a cell manner, generate heat during the charging and discharging of the ESS battery, thereby enabling stable charging and discharging of the ESS battery.

[0004] However, existing systems for managing the temperature of energy storage system (ESS) batteries can only maintain the target temperature and cannot manage the heat generation of the ESS battery through active cooling control based on the charging and discharging environment of the ESS battery. Therefore, they suffer from insufficient heat management of the ESS battery and reduced charging efficiency.

[0005] Prior technology documents

[0006] Patent documents

[0007] (Patent Document 1) 1. Korean Patent Publication No. 10-2020-0009566 (Published on January 30, 2020) Summary of the Invention

[0008] The present invention aims to provide a cooling system and its operating method for an energy storage system (ESS) battery that, through communication with a battery control unit, performs heat management by providing a cooling control signal from a cooling control unit during the charging and discharging process of the ESS battery. This system allows for proactive heat management based on the charging and discharging environment of the ESS battery by providing a cooling control signal to the cooling unit, thereby improving the charging efficiency of the ESS battery.

[0009] The purpose of the embodiments of the present invention is not limited to the purposes mentioned above. Those skilled in the art to which this invention pertains will further understand other purposes not mentioned through the following description.

[0010] According to one aspect of the present invention, a cooler operating system for an energy storage system (ESS) battery can be provided, comprising: an energy storage system (ESS) battery; a battery control unit for controlling the charging and discharging of the energy storage system (ESS) battery; a cooler unit for cooling the energy storage system (ESS) battery according to a cooling control signal during the charging and discharging process of the energy storage system (ESS) battery; and a cooling control unit for performing heat management by providing the cooling control signal during the charging and discharging process of the energy storage system (ESS) battery through mutual communication with the battery control unit, wherein the cooling control signal is provided to the cooler unit when at least one of a cooling start signal input from the battery control unit and a preset cooler temperature condition is met.

[0011] Furthermore, according to one aspect of the present invention, a cooling system for an energy storage system (ESS) battery can be provided, wherein the cooling control unit sets the cooling temperature conditions using the temperature of the cooling inlet water flowing into the cooling unit and the temperature of the cooling outlet water flowing out of the cooling unit.

[0012] Furthermore, according to one aspect of the present invention, a cooler operating system for an energy storage system (ESS) battery can be provided, wherein the preset cooler temperature conditions include a first cooler temperature condition and a second cooler temperature condition that is relatively larger than the first cooler temperature condition.

[0013] Furthermore, according to one aspect of the present invention, a cooling system for an energy storage system (ESS) battery can be provided, wherein the cooling control unit provides the cooling control signal to the cooling unit when both the first cooling temperature condition and the second cooling temperature condition are simultaneously met.

[0014] Furthermore, according to another aspect of the present invention, a method for operating a cooler operating system for an energy storage system (ESS) battery can be provided, comprising: performing a charging and discharging step of the energy storage system (ESS) battery under the control of a battery control unit; checking whether a cooling start signal input is received by a cooling control unit through mutual communication with the battery control unit; providing a cooling control signal from the cooling control unit to a cooler unit when the cooling start signal input is received; checking whether a preset cooler temperature condition is met by the cooling control unit when the cooling start signal input is not received; providing the cooling control signal from the cooling control unit to the cooler unit when the preset cooler temperature condition is met; and performing heat management of the energy storage system (ESS) battery by the cooler unit according to the cooling control signal.

[0015] Furthermore, according to another aspect of the present invention, an operating method for a cooler operating system for an energy storage system (ESS) battery can be provided, which, before the step of checking whether a preset cooler temperature condition is met, further includes a step of setting the cooler temperature condition using the cooler inlet water temperature flowing into the cooler unit and the cooler outlet water temperature flowing out of the cooler unit.

[0016] Furthermore, according to another aspect of the present invention, an operating method for a cooler operating system for an energy storage system (ESS) battery can be provided, wherein the step of setting the cooler temperature conditions includes a first cooler temperature condition and a second cooler temperature condition that is relatively larger than the first cooler temperature condition.

[0017] Furthermore, according to another aspect of the present invention, an operating method for a cooler operating system for an energy storage system (ESS) battery can be provided, wherein in the step of checking whether a preset cooler temperature condition is met, it is checked whether both the first cooler temperature condition and the second cooler temperature condition are met simultaneously.

[0018] This invention can communicate with the battery control unit to provide a cooling control signal from the cooling control unit during the charging and discharging process of the energy storage system (ESS) battery and thereby perform heat management. In the event that at least one of the cooling start signal input of the battery control unit and the satisfaction of a preset cooler temperature condition is met, heat management can be actively performed according to the charging and discharging environment of the energy storage system (ESS) battery by providing a cooling control signal to the cooler unit, thereby improving the charging efficiency of the energy storage system (ESS) battery. Attached Figure Description

[0019] Figure 1 This is a block diagram of the operating system of a battery cooler for an energy storage system (ESS) according to one embodiment of the present invention.

[0020] Figure 2 This is a flowchart illustrating the operation of a battery cooler in an energy storage system (ESS) according to another embodiment of the present invention.

[0021] Figure 3 This is a flowchart illustrating the process of operating according to a first cooler temperature condition and a second cooler temperature condition according to another embodiment of the present invention.

[0022] Figure 4 This is a schematic diagram illustrating the operation of a battery cooler for an energy storage system (ESS) according to another embodiment of the present invention.

[0023] [Symbol Explanation]

[0024] 110: Energy Storage System (ESS) Battery

[0025] 120: Battery Control Unit

[0026] 130: Cooling control unit

[0027] 140: Refrigeration Unit Detailed Implementation

[0028] The advantages and features of the embodiments of the present invention, and the methods for achieving them, will become even clearer through the following detailed description of the embodiments with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in many different forms. These embodiments are merely for the purpose of more fully disclosing the present invention and more completely introducing the scope of the invention to those skilled in the art. The present invention should only be defined within the scope of the claims. Throughout this specification, the same reference numerals denote the same constituent elements.

[0029] In describing embodiments of the present invention, detailed descriptions of well-known functions or configurations will be omitted if it is determined that such specific descriptions may obscure the essence of the invention. Furthermore, the terminology used thereafter is defined in consideration of its functionality in the embodiments of the present invention and may change according to the intentions or conventions of users and users. Therefore, it should be defined based on the overall content of the present invention.

[0030] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0031] Figure 1 This is a block diagram of the operating system of a battery cooler for an energy storage system (ESS) according to one embodiment of the present invention.

[0032] See Figure 1 According to one embodiment of the present invention, the energy storage system (ESS) battery cooler operating system may include an energy storage system (ESS) battery 110, a battery control unit 120, a cooling control unit 130, and a cooler unit 140, etc.

[0033] The energy storage system (ESS) battery 110 includes a battery module composed of battery cells, such as a lithium-ion battery, which can be charged or discharged under the control of the battery control unit 120.

[0034] The battery control unit 120 includes a battery control unit (BCU) that controls the entire energy storage system (ESS) battery 110, and a battery control panel (BCP) that controls the internal components of the energy storage system (ESS) battery 110. It is a unit that controls the charging and discharging of the energy storage system (ESS) battery 110. It can communicate with the cooling control unit 130 and control the charging and discharging of the energy storage system (ESS) battery 110.

[0035] As described above, the battery control unit 120 can provide a cooling start signal to the cooling control unit 130 in order to cool the energy storage system (ESS) battery 110 through the cooler unit 140 during the charging and discharging process of the energy storage system (ESS) battery 110.

[0036] The cooling control unit 130 can communicate with the battery control unit 120 to provide cooling control signals during the charging and discharging of the energy storage system (ESS) battery and thereby perform heat management. It can provide cooling control signals to the cooler unit 140 when the cooling start signal input of the battery control unit 120 is received and at least one of the preset cooler temperature conditions is met.

[0037] The cooling control unit 130 described above can set the cooler temperature conditions using the cooler inlet water temperature flowing into the cooler unit 140 and the cooler outlet water temperature flowing out of the cooler unit 140. The preset cooler temperature conditions described above may include a first cooler temperature condition and a second cooler temperature condition that is relatively larger than the first cooler temperature condition.

[0038] For example, during the charging and discharging of the energy storage system (ESS) battery 110 via the battery control unit 120, the cooling control unit 130 can check for a cooling start signal input by communicating with the battery control unit 120, and provide a cooling control signal to the cooler unit 140 if a cooling start signal input is received.

[0039] In addition, the cooling control unit 130 can check whether the preset cooler temperature conditions are met when there is no cooling start signal input from the battery control unit 120, and provide a cooling control signal to the cooler unit 140 when the preset cooler temperature conditions are met.

[0040] The cooling control unit 130 can provide a cooling control signal to the cooling unit 140 when both the first and second cooling temperature conditions are met during the process of checking whether the preset cooling temperature conditions are met.

[0041] For example, the cooling control unit 130 can set the cooling mode elapsed time (N) to an initial value (0), and receive the cooler outlet water temperature (T1) and cooler inlet water temperature (T2) obtained by the temperature sensor unit 144 equipped in the cooler unit 140 from the cooler unit 140, thereby checking whether the difference between the cooler inlet water temperature (T2) and the cooler outlet water temperature (T1) (T2-T1) exceeds the preset first cooler temperature value (SV.temp#1, for example 1) (T2-T1>SV.temp#1).

[0042] Furthermore, if the difference between the inlet water temperature (T2) and the outlet water temperature (T1) of the cooler (T2-T1) is less than or equal to the preset first cooler temperature value (SV.temp#1), the cooling control unit 130 may return to the step of setting the cooling mode elapsed time (N) to the initial value (0). However, if the difference between the inlet water temperature (T2) and the outlet water temperature (T1) of the cooler (T2-T1) exceeds the preset first cooler temperature value (SV.temp#1), the cooling mode elapsed time (N) may be cumulatively set by adding a preset additional value (1) (N = N + 1).

[0043] In addition, the cooling control unit 130 can check whether the difference between the cooler inlet water temperature (T2) and the cooler outlet water temperature (T1) (T2-T1) reaches a preset second cooler temperature value (SV.t emp#2, for example 2), and if the difference between the cooler inlet water temperature (T2) and the cooler outlet water temperature (T1) (T2-T1) reaches or exceeds the preset second cooler temperature value (SV.t emp#2), it provides a cooling control signal for starting the cooler unit 140.

[0044] Furthermore, if the difference between the cooler inlet water temperature (T2) and the cooler outlet water temperature (T1) (T2-T1) is less than the preset second cooler temperature value (SV.time#2), the cooling control unit 130 may check whether the accumulated cooling mode elapsed time (N) is less than or equal to the preset start-up observation time (SV.Time#1). If the accumulated cooling mode elapsed time (N) is less than or equal to the preset start-up observation time (SV.Time#1), the control unit 130 may return to the step of receiving the cooler outlet water temperature (T1) and the cooler inlet water temperature (T2) from the cooler unit 140. If the accumulated cooling mode elapsed time (N) exceeds the preset start-up observation time (SV.Time#1), the control unit 130 may provide a cooling control signal for starting the cooler unit 140.

[0045] The cooler unit 140 is a unit that cools the energy storage system (ESS) battery 110 according to the cooling control signal provided by the cooling control unit 130 during the charging and discharging process. It may include a refrigerant circulation unit 141, a cooler 142, a cooling water circulation unit 143, and a temperature sensor unit 144.

[0046] The refrigerant circulation section 141 includes components such as a compressor, condenser, expander, and evaporator, and the refrigerant can circulate through the interior of the refrigerator 142.

[0047] In addition, the cooler 142 can control the heat exchange between the refrigerant circulating in the refrigerant circulation section 141 and the cooling water circulating in the cooling water circulation section 143, thereby allowing the cooling water at a preset temperature to circulate to the energy storage system (ESS) battery 110.

[0048] Furthermore, the cooling water circulation section 143 allows the cooling water circulating inside the refrigerator 142 to exchange heat with the refrigerant circulating through the refrigerant circulation section 141, and allows the cooling water to circulate inside the metal plate at the bottom of each battery module in the energy storage system (ESS) battery 110 and inside the refrigerator 142.

[0049] By means of cooling water circulating through the internal flow path of the metal plate as described above, the temperature of each battery module equipped in the energy storage system (ESS) battery 110 can be maintained at the target temperature.

[0050] In addition, the temperature sensor unit 144 can be equipped on the cooling water circulation line inside the refrigerator 142, and can measure and provide the cooling control unit 130 the cooling water outlet temperature (T1) that flows out of the refrigerator 142 through the cooling water circulation unit 143 to the metal plate and the refrigerator inlet temperature (T2) that circulates in the metal plate and flows into the refrigerator 142 through the cooling water circulation unit 143.

[0051] Therefore, according to one embodiment of the present invention, a cooling control signal can be provided from the cooling control unit during the charging and discharging process of the energy storage system (ESS) battery by communicating with the battery control unit, thereby performing heat management. In the case of a cooling start signal input from the battery control unit and at least one of a preset cooler temperature condition being met, heat management can be actively performed according to the charging and discharging environment of the energy storage system (ESS) battery by providing a cooling control signal to the cooler unit, thereby improving the charging efficiency of the energy storage system (ESS) battery.

[0052] Figure 2 This is a flowchart illustrating the operation of a battery cooler in an energy storage system (ESS) according to another embodiment of the present invention. Figure 3 This is a flowchart illustrating the process of operating according to a first cooler temperature condition and a second cooler temperature condition according to another embodiment of the present invention. Figure 4 This is a schematic diagram illustrating the operation of a battery cooler for an energy storage system (ESS) according to another embodiment of the present invention.

[0053] See Figures 2 to 4In step 210, the charging and discharging of the energy storage system (ESS) battery 110 can be performed under the control of the battery control unit 120.

[0054] In addition, in step 220, the cooling control unit 130 can check whether there is a cooling start signal input by communicating with the battery control unit 120.

[0055] Based on the inspection results of step 220, in the presence of a cooling start signal input, in step 250, a cooling control signal can be provided from the cooling control unit 130 to the refrigeration unit 140.

[0056] Furthermore, in step 230, the cooler temperature conditions can be set using the cooler inlet water temperature (T2) flowing from the cooling control unit 130 into the cooler unit 140 and the cooler outlet water temperature T1 flowing out of the cooler unit 140.

[0057] In step 230 of setting the refrigerator temperature conditions as described above, the conditions can be set to include a first refrigerator temperature condition and a second refrigerator temperature condition that is relatively larger than the first refrigerator temperature condition.

[0058] The step 230 of setting the cooler temperature conditions as described above is illustrated and explained as an example of the case where it is executed after step 220 of checking whether there is a cooling start signal input. However, this is only for the convenience of explanation and can be executed at any step before step 240 of checking whether the preset cooler temperature conditions are met, which will be explained later.

[0059] Furthermore, based on the inspection results of step 220, in the absence of a cooling start signal input, in step 240, the cooling control unit 130 can check whether the preset cooler temperature conditions are met.

[0060] In step 240, which checks whether the preset refrigerator temperature conditions are met as described above, it can be checked whether both the first refrigerator temperature condition and the second refrigerator temperature condition are met simultaneously.

[0061] Based on the inspection results of step 240, if the preset refrigerator temperature conditions are met, in step 250, a cooling control signal can be provided from the cooling control unit 130 to the refrigerator unit 140.

[0062] Next, in step 260, the cooler unit 140 can perform heat management (i.e., cooling water circulation, etc.) of the energy storage system (ESS) battery according to the cooling control signal from the cooling control unit 130.

[0063] Next, please refer to Figure 3The steps 240 and 250, as described above, for checking whether the preset cooler temperature conditions are met, will be explained in detail. In step 310, the cooling control unit 130 can set the cooling mode elapsed time (N) to an initial value (0).

[0064] Furthermore, in step 320, the cooling control unit 130 can receive the cooler outlet water temperature (T1) and cooler inlet water temperature (T2) obtained from the cooler unit 140 through the temperature sensor unit 144 provided in the cooler unit 140.

[0065] Next, in step 330, the cooling control unit 130 can check whether the difference between the cooler inlet water temperature (T2) and the cooler outlet water temperature (T1) (T2-T1) exceeds the preset first cooler temperature value (SV.temp#1, for example 1).

[0066] Based on the inspection results of step 330, if the difference between the inlet water temperature (T2) and the outlet water temperature (T1) of the cooler (T2-T1) is below the preset first cooler temperature value (SV.t emp#1), the process can return to step 310 where the cooling control unit 130 sets the cooling mode elapsed time (N) to the initial value (0).

[0067] Furthermore, based on the inspection results of step 330, if the difference between the inlet water temperature (T2) and the outlet water temperature (T1) of the cooler (T2-T1) exceeds the preset first cooler temperature value (SV.t emp#1), in step 340, the cooling control unit 130 can accumulate and set the cooling mode elapsed time (N) by adding a preset additional value (1) (N=N+1).

[0068] Next, in step 350, the cooling control unit 130 can check whether the difference between the cooler inlet water temperature (T2) and the cooler outlet water temperature (T1) (T2-T1≥SV.t emp#2) is greater than or equal to the preset first cooler temperature value (SV.t emp#2, for example 2).

[0069] Based on the inspection results of step 350, if the difference between the inlet water temperature (T2) and the outlet water temperature (T1) of the cooler (T2-T1) reaches or exceeds the preset second cooler temperature value (SV.t emp#1), a cooling control signal for starting the cooler unit 140 can be provided in step 370.

[0070] Furthermore, based on the inspection results of step 350, if the difference between the inlet water temperature (T2) and the outlet water temperature (T1) of the cooler (T2-T1) is less than the preset first cooler temperature value (SV.time#1), in step 360, the cooling control unit 130 may check whether the accumulated cooling mode elapsed time (N) is less than the preset start-up observation time (SV.Time#1).

[0071] Based on the inspection results of step 360, if the accumulated cooling mode elapsed time (N) is less than the preset startup observation time (SV.Time#1), the process can return to step 320, where the cooling control unit 130 receives the cooler outlet water temperature (T1) and cooler inlet water temperature (T2) from the cooler unit 140.

[0072] Furthermore, based on the inspection results of step 360, if the accumulated cooling mode elapsed time (N) exceeds the preset startup observation time (SV.Time#1), in step 370, the cooling control unit 130 may provide a cooling control signal for starting the cooler unit 140.

[0073] As described above, in another embodiment of the present invention, such as Figure 4 As shown, in the mode where the cooling control unit 130 starts the cooler unit 140, four situations may occur. Among them, state A refers to the situation where the battery control unit 120 provides a cooling start signal (i.e., an external trigger) to the cooling control unit 130, while state B refers to the situation where the preset cooler temperature condition is met in the cooling control unit 130.

[0074] In this context, No. 1 refers to a situation where state A is stopped (Fals e) and state B is changing (True). Under these conditions, the cooling control unit 130 can determine it as running (True) and provide a cooling control signal to start the refrigeration unit 140. Conversely, if state A is stopped (Fals e) and state B is changing (True), it can also be determined as stopped (Fals e) and the refrigeration unit 140 will be stopped (not started).

[0075] Furthermore, No.2 refers to the situation where state A is activated (True) and state B is in flux (True). In the case described above, the cooling control unit 130 can determine that it is running (True) and provide a cooling control signal to activate the refrigeration unit 140.

[0076] Furthermore, No.3 refers to the situation where state A is stopped (Fals e) and state B is maintained (Fals e). In the case described above, the cooling control unit 130 can determine that it is stopped (Fals e) and stop (do not start) the refrigeration unit 140.

[0077] Furthermore, No.4 refers to the situation where state A is activated (True) and state B is maintained (False). In the case described above, the cooling control unit 130 can determine that it is running (True) and provide a cooling control signal to activate the refrigeration unit 140.

[0078] That is, the cooler unit 140 can be started when only one of states A and B is true.

[0079] Therefore, according to another embodiment of the present invention, a cooling control signal can be provided from the cooling control unit during the charging and discharging process of the energy storage system (ESS) battery by communicating with the battery control unit, thereby performing heat management. In the case of a cooling start signal input from the battery control unit and at least one of a preset cooler temperature condition being met, heat management can be actively performed according to the charging and discharging environment of the energy storage system (ESS) battery by providing a cooling control signal to the cooler unit, thereby improving the charging efficiency of the energy storage system (ESS) battery.

[0080] Several embodiments of the present invention have been described in the foregoing description, but the present invention is not limited thereto. Those skilled in the art to which the present invention pertains should understand that the present invention can be subject to various substitutions, modifications and alterations without departing from the present technical concept.

Claims

1. A cooling system for an energy storage system battery, comprising: Energy storage system battery; The battery control unit controls the charging and discharging of the battery in the energy storage system. The cooling unit cools the energy storage system battery according to a cooling control signal during the charging and discharging process of the energy storage system battery. as well as, The cooling control unit, through mutual communication with the battery control unit, performs heat management by providing the cooling control signal during the charging and discharging process of the energy storage system battery. The cooling control signal is provided to the cooler unit when at least one of the cooling start signal input of the battery control unit and the pre-set cooler temperature condition is met.

2. The battery cooler operating system of the energy storage system according to claim 1, The cooling control unit sets the cooler temperature conditions using the cooler inlet water temperature flowing into the cooler unit and the cooler outlet water temperature flowing out of the cooler unit.

3. The battery cooler operating system for the energy storage system according to claim 2, The preset refrigerator temperature conditions include a first refrigerator temperature condition and a second refrigerator temperature condition that is relatively larger than the first refrigerator temperature condition.

4. The battery cooler operating system for the energy storage system according to claim 3, The cooling control unit provides the cooling control signal to the cooling unit when both the first and second cooler temperature conditions are met.

5. A method for operating a battery cooler operating system for an energy storage system, comprising: The charging and discharging steps of the energy storage system battery are executed under the control of the battery control unit; The step of checking for a cooling start signal input by the cooling control unit through mutual communication with the battery control unit; The step of providing a cooling control signal from the cooling control unit to the refrigeration unit when the cooling start signal is input; In the absence of the cooling start signal input, the cooling control unit checks whether the preset cooler temperature conditions are met. The step of providing the cooling control signal from the cooling control unit to the cooling unit when the preset cooling temperature conditions are met; as well as, According to the cooling control signal, the cooler unit performs the steps of heat management for the energy storage system battery.

6. The operating method of the battery cooler operating system for the energy storage system according to claim 5, Before the step of checking whether the preset refrigerator temperature condition is met, the following is also included: The step of setting the temperature conditions of the refrigerator using the temperature of the refrigerator inlet water flowing into the refrigerator unit and the temperature of the refrigerator outlet water flowing out of the refrigerator unit.

7. The operating method of the battery cooler operating system of the energy storage system according to claim 6, In the step of setting the temperature conditions of the cooler, The temperature is set to include a first refrigerator temperature condition and a second refrigerator temperature condition that is relatively larger than the first refrigerator temperature condition.

8. The operating method of the battery cooler operating system of the energy storage system according to claim 7, In the step of checking whether the preset refrigerator temperature conditions are met, Check whether the first refrigerator temperature condition and the second refrigerator temperature condition are met simultaneously.

Images