Refrigeration appliance and method of controlling a refrigeration appliance

Abstract

The application provides a refrigeration device and a control method of the refrigeration device. The refrigeration device comprises a refrigerant circulation system and a carrier refrigerant circulation system. The refrigerant circulation system comprises a heat exchanger for heat exchange between refrigerant and carrier refrigerant. The carrier refrigerant circulation system comprises a pump, a carrier refrigerant pipeline sequentially connected with an outlet of the pump, a refrigeration device, the heat exchanger and an inlet of the pump to form a carrier refrigerant loop, and an electric heating device configured to heat carrier refrigerant in the carrier refrigerant pipeline between the heat exchanger and the inlet of the pump. The electric heating device comprises two or more electric heating units independently started and stopped from each other.

Description

Technical Field

[0001] This application relates to the field of refrigeration technology, and in particular to a refrigeration device and a control method for the refrigeration device. Background Technology

[0002] Specialized refrigeration equipment operates in harsh environments, with some requiring operation at -40°C or lower. This is especially true for equipment using ethylene glycol solution as a refrigerant. In low-temperature environments, ethylene glycol refrigerant has extremely high viscosity and very poor fluidity. Starting the pump under these conditions results in a large starting torque, which can easily damage the motor or cause bearing breakage.

[0003] In related technologies, the refrigerant circulation system relies on the self-heating of the refrigerant when the pump starts, allowing the refrigerant to flow slowly, which places high demands on the reliability of the pump.

[0004] The above statements are for the purpose of providing background information in relation to this application only, and do not necessarily constitute prior art. Summary of the Invention

[0005] The purpose of this application is to provide a refrigeration device and a control method for the refrigeration device, which aims to solve the problem of high reliability requirements for the pump when the refrigerant circulation system relies on the self-heating of the refrigerant when the pump starts.

[0006] A first aspect of this application provides a refrigeration device, including a refrigerant circulation system and a secondary refrigerant circulation system. The refrigerant circulation system includes a heat exchanger for heat exchange between the refrigerant and the secondary refrigerant. The secondary refrigerant circulation system includes:

[0007] Pump;

[0008] A refrigerant pipeline is sequentially connected to the pump outlet, the refrigerated equipment, the heat exchanger, and the pump inlet to form a refrigerant circuit; and

[0009] An electric heating device configured to heat the refrigerant in the refrigerant line between the heat exchanger and the pump inlet, the electric heating device comprising two or more electric heating units that can be started and stopped independently of each other.

[0010] In some embodiments of the refrigeration equipment, the electric heating device includes four of the electric heating units.

[0011] In some embodiments of the refrigeration equipment, the distance between the electric heating device and the inlet of the pump is less than or equal to 0.5 meters.

[0012] In some embodiments of the refrigeration equipment,

[0013] The pump is a variable frequency pump; and / or

[0014] The refrigerant includes ethylene glycol.

[0015] In some embodiments of the refrigeration apparatus, the refrigeration apparatus includes:

[0016] A temperature detection device is configured to acquire temperature information characterizing the temperature of the refrigerant at at least one location in the refrigerant circuit and / or the ambient temperature of the refrigerant circuit; and

[0017] A control device, signal-connected to the temperature detection device and the electric heating device, is configured to control the start and stop of the two or more electric heating units based on the temperature information detected by the temperature detection device.

[0018] In some embodiments of the refrigeration equipment, the temperature detection device includes:

[0019] A first temperature detection unit is configured to detect a first refrigerant temperature T1 in the refrigerant pipeline between the heat exchanger and the electric heating device, the temperature information including the first refrigerant temperature T1; and / or

[0020] A second temperature detection unit is configured to detect a second refrigerant temperature T2 at the pump inlet, the temperature information including the second refrigerant temperature T2; and / or

[0021] A third temperature detection unit is configured to detect the third refrigerant temperature T3 at the outlet of the pump, the temperature information including the third refrigerant temperature T3; and / or

[0022] The fourth temperature detection unit is configured to detect the ambient temperature T0 of the environment in which the refrigerant circuit is located, and the temperature information includes the ambient temperature T0.

[0023] A second aspect of this application provides a control method for a refrigeration device according to the first aspect of this application, comprising:

[0024] The number of electric heating units to be activated is determined based on temperature information characterizing the temperature of the refrigerant at at least one location in the refrigerant circuit and / or the ambient temperature of the refrigerant circuit; and

[0025] Turn on the required number of the electric heating units.

[0026] In some embodiments of the control method, the temperature information includes:

[0027] The first refrigerant temperature T1 in the refrigerant pipeline between the heat exchanger and the electric heating device; and / or

[0028] The second refrigerant temperature T2 at the pump inlet; and / or

[0029] The third refrigerant temperature T3 at the pump outlet; and / or

[0030] The ambient temperature T0 is the temperature of the environment in which the refrigerant circuit is located.

[0031] In some embodiments of the control method, activating the required number of the electric heating units includes:

[0032] Prioritize activating the required number of electric heating units closer to the pump inlet; or

[0033] Prioritize activating the required number of electric heating units with shorter usage times.

[0034] In some embodiments of the control method, the control method includes:

[0035] Before the pump is turned on, determine the number of electric heating units that need to be turned on; and

[0036] The pump is turned on after a predetermined time period following the activation of the required number of the electric heating units.

[0037] In some embodiments of the control method, the pump is a variable frequency pump, and the control method includes:

[0038] If T2 < high-frequency start preset temperature, the variable frequency pump starts at a high-frequency start frequency higher than the normal start frequency.

[0039] If T2 ≥ high frequency start preset temperature, the variable frequency pump starts at normal start frequency, where T2 is the second refrigerant temperature at the pump inlet.

[0040] Where T2 is the second refrigerant temperature at the pump inlet.

[0041] In some embodiments of the control method, -45℃≤high-frequency start preset temperature≤-10℃.

[0042] In some embodiments of the control method, the temperature information includes the first refrigerant temperature T1, and the lower the first refrigerant temperature T1, the more electric heating units need to be turned on.

[0043] In some embodiments of the control method, the electric heating device includes four electric heating units, and the control method includes:

[0044] When T1 ≤ the first preset heating temperature, the four electric heating units are turned on. After the four electric heating units are turned on for a first preset time period, the pump is started. T1 is the first refrigerant temperature in the refrigerant pipeline between the heat exchanger and the electric heating device.

[0045] When the first preset heating temperature < T1 ≤ the second preset heating temperature, the three electric heating units are turned on. After the three electric heating units have been turned on for a second preset time period, the pump is started.

[0046] When the second preset heating temperature < T1 ≤ the third preset heating temperature, the two electric heating units are turned on. After the two electric heating units have been turned on for a third preset time period, the pump is started.

[0047] When the third preset heating temperature < T1 ≤ the fourth preset heating temperature, two of the electric heating units are turned on. After the two electric heating units have been turned on for a fourth preset time period, the pump is started. Alternatively, one electric heating unit is turned on. After the one electric heating unit has been turned on for a fifth preset time period, the pump is started. The fifth preset time period is longer than the fourth preset time period.

[0048] In some embodiments of the control method, when the fourth preset heating temperature is <T1, if T3 is <T4, at least one of the electric heating units is turned on, and if T3 is ≥T4, the electric heating device is in a closed state, where T3 is the third refrigerant temperature at the outlet of the pump, and T4 is the refrigerant required temperature of the cooling equipment.

[0049] In some embodiments of the control method,

[0050] -45℃≤First preset heating temperature≤-40℃; and / or

[0051] 15s ≤ first preset time period ≤ 30s; and / or

[0052] -40℃ < second preset heating temperature ≤ -30℃; and / or

[0053] 15s ≤ second preset time period ≤ 30s; and / or

[0054] -30℃ < third preset heating temperature ≤ -20℃; and / or

[0055] 15s ≤ third preset time period ≤ 30s;

[0056] -20℃ < fourth preset heating temperature ≤ -10℃; and / or

[0057] 5s ≤ second preset time period ≤ 15s; and / or

[0058] 15s ≤ Fifth preset time period ≤ 30s;

[0059] Among the first preset heating temperature, the second preset heating temperature, the third preset heating temperature and the fourth preset heating temperature, the difference between any two adjacent preset heating temperatures is within the range of 5℃ to 15℃.

[0060] In some embodiments of the control method, the pump is a variable frequency pump, and the control method includes:

[0061] If T1 ≤ the fourth preset heating temperature, the pump, including the variable frequency pump, is started at a high frequency higher than the normal start frequency. After the variable frequency pump is started, it runs at the high frequency or at a frequency lower than the high frequency.

[0062] In some embodiments of the control method, during the operation of the refrigeration equipment, if the load of the refrigeration equipment drops to a minimum and T1 < T4, at least one of the electric heating units is turned on until T3 ≥ T4, where T3 is the third refrigerant temperature at the outlet of the pump, and T4 is the refrigerant temperature required by the refrigeration equipment.

[0063] Based on the refrigeration equipment and control method provided in this application, the refrigerant, such as an ethylene glycol solution, flowing towards the pump inlet can be heated by an electric heating device. This improves the temperature and flowability of the refrigerant at the pump inlet, facilitating the pump's downstream delivery of the refrigerant and reducing the reliability requirements of the pump. However, if the electric heating device is a high-power unit, the rapid heating after activation may cause extremely rapid temperature increases in some areas of the refrigerant. Because the heat transfer rate of refrigerants like ethylene glycol solutions is slow, the refrigerant temperature at the electric heating unit may be high, potentially reaching near boiling point, while the refrigerant temperature at the pump inlet remains low. As the refrigerant flows, the pump experiences rapid temperature changes in the refrigerant during delivery, which can easily lead to bearing seizure and stalling. Compared to a technical solution where the electric heating device consists of a single, high-power electric heating unit, the refrigeration equipment in this embodiment of the application has two or more electric heating units that start and stop independently. This allows for the selection of appropriate heating power to ensure that the refrigerant flowing to the pump inlet has a suitable temperature. Furthermore, when a larger heating power is required, the refrigerant can be gradually heated over a longer refrigerant circuit, allowing it to gradually heat up during flow. This ensures that the refrigerant flowing to the pump inlet remains within a suitable temperature range, facilitating temperature stability during pumping. This reduces or prevents bearing seizure or stalling caused by rapid temperature changes in the pumped refrigerant, and also lowers the reliability requirements for the pump.

[0064] Other features and advantages of this application will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0065] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0066] Figure 1 This is a schematic diagram of the refrigerant circulation system of the refrigeration equipment according to an embodiment of this application.

[0067] Figure 2 This is a schematic diagram illustrating the control principle of the temperature detection device, control device, and electric heating device in the refrigeration cycle system of the refrigeration equipment according to an embodiment of this application.

[0068] Figure 3 This is a flowchart illustrating the control method of a refrigeration device according to an embodiment of this application. Detailed Implementation

[0069] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0070] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0071] In the description of this application, it should be understood that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application.

[0072] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0073] like Figure 1 As shown, a first aspect of this application provides a refrigeration device, including a refrigerant circulation system and a secondary refrigerant circulation system. The refrigerant circulation system includes a heat exchanger 3 for heat exchange between the refrigerant and the secondary refrigerant. The secondary refrigerant circulation system includes a pump 1, a secondary refrigerant pipeline 5, and an electric heating device 4. The secondary refrigerant pipeline 5 is sequentially connected to the outlet of the pump 1, the refrigerated equipment 2, the heat exchanger 3, and the inlet of the pump 1 to form a secondary refrigerant circuit. The electric heating device 4 is configured to heat the secondary refrigerant within the secondary refrigerant pipeline 5 between the heat exchanger 3 and the inlet of the pump 1. The electric heating device 4 includes two or more electric heating units that can be started and stopped independently of each other.

[0074] The refrigeration equipment in this embodiment can heat the refrigerant, such as an ethylene glycol solution, flowing towards the pump inlet using an electric heating device. This improves the temperature and flowability of the refrigerant at the pump inlet, facilitating downstream pumping and reducing the reliability requirements of the pump. However, if the electric heating device is a high-power unit, the rapid heating after activation may cause extremely fast local refrigerant temperature rise. Because refrigerants like ethylene glycol solutions have slow heat transfer rates, the refrigerant temperature at the heating unit may be high, potentially reaching near boiling point, while the temperature at the pump inlet remains low. As the refrigerant flows, the pump experiences rapid temperature changes during pumping, which can easily lead to bearing seizure and stalling. Compared to a technical solution where the electric heating device consists of a single, high-power electric heating unit, the refrigeration equipment in this embodiment of the application has two or more electric heating units that start and stop independently. This allows for the selection of appropriate heating power to ensure that the refrigerant flowing to the pump inlet has a suitable temperature. Furthermore, when a larger heating power is required, the refrigerant can be gradually heated over a longer refrigerant circuit, allowing it to gradually heat up during flow. This ensures that the refrigerant flowing to the pump inlet remains within a suitable temperature range, facilitating temperature stability during pumping. This reduces or prevents bearing seizure or stalling caused by rapid temperature changes in the pumped refrigerant, and also lowers the reliability requirements for the pump.

[0075] like Figure 1 and Figure 2 As shown, in some embodiments of the refrigeration equipment, the electric heating device 4 includes four electric heating units. For example... Figure 2As shown, the four electric heating units are the first electric heating unit 41, the second electric heating unit 42, the third electric heating unit 43, and the fourth electric heating unit 44. The heating power of each electric heating unit can be the same or different, and the length of the heating section of each electric heating unit along the refrigerant pipeline 5 can be the same or different.

[0076] Setting the number of electric heating units appropriately allows for the provision of the appropriate number of units to be turned on according to the heating power requirements. This not only helps the refrigerant flowing to the pump inlet reach the appropriate temperature but also saves energy.

[0077] In some embodiments of the refrigeration equipment, the distance between the electric heating device and the inlet of pump 1 is less than or equal to 0.5 meters.

[0078] Setting the distance between the electric heating device and the pump inlet to an appropriate position facilitates the timely entry of the heated refrigerant into the pump, reduces heat loss due to the low-temperature environment, and thus helps save energy.

[0079] In some embodiments of the refrigeration equipment, pump 1 is a variable frequency pump. Setting pump 1 as a variable frequency pump allows for selection of the start-up frequency or operating frequency based on the performance of the refrigerant at the pump inlet, thereby facilitating the smooth downstream delivery of the refrigerant.

[0080] In some embodiments of the refrigeration equipment, the refrigerant includes ethylene glycol. Refrigerants including ethylene glycol have a low freezing point, which is beneficial for the refrigeration equipment to operate normally in low-temperature environments.

[0081] like Figure 2 As shown, in some embodiments of the refrigeration equipment, the refrigeration equipment includes a temperature detection device 6 and a control device 7. The temperature detection device 6 is configured to acquire temperature information characterizing the temperature of the refrigerant at at least one location in the refrigerant circuit and / or the ambient temperature of the refrigerant circuit. The control device 7 is signal-connected to the temperature detection device 6 and the electric heating device 4, and is configured to control the start and stop of two or more electric heating units based on the temperature information detected by the temperature detection device 6.

[0082] The installation of temperature detection device 6 and control device 7 facilitates the automatic control of electric heating device 4 and enables more accurate temperature control of the refrigerant at the pump inlet, thereby allowing the refrigeration equipment to smoothly perform its refrigeration function.

[0083] The temperature detection device 6 may include, for example, one or more temperature sensors.

[0084] The control device 7 may be implemented, for example, as a general-purpose processor, a programmable logic controller (PLC), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or any suitable combination thereof for performing the functions described in this disclosure.

[0085] In some embodiments of the refrigeration equipment, the temperature detection device 6 includes:

[0086] The first temperature detection unit 61 is configured to detect the first refrigerant temperature T1 in the refrigerant pipeline 5 between the heat exchanger 3 and the electric heating device 4, and the temperature information includes the first refrigerant temperature T1; and / or

[0087] The second temperature detection unit 62 is configured to detect the second refrigerant temperature T2 at the inlet of pump 1, and the temperature information includes the second refrigerant temperature T2; and / or

[0088] The third temperature detection unit 63 is configured to detect the third refrigerant temperature T3 at the outlet of pump 1, and the temperature information includes the third refrigerant temperature T3; and / or

[0089] The fourth temperature detection unit 64 is configured to detect the ambient temperature T0 of the environment in which the refrigerant circuit is located, and the temperature information includes the ambient temperature T0.

[0090] The first temperature T1 of the refrigerant in the refrigerant pipeline 5 between the heat exchanger 3 and the electric heating device 4 is detected by the first temperature detection unit 61. The heating power required to heat the refrigerant to a suitable temperature can be determined based on T1, which is helpful for selecting the appropriate number of electric heating units.

[0091] The second temperature detection unit 62 detects the second refrigerant temperature T2 at the inlet of pump 1. Based on the second refrigerant temperature T2, it can be determined whether the refrigerant temperature at the pump inlet is appropriate. The pump's operating frequency can also be determined based on the second refrigerant temperature T2, so that the pump can provide the appropriate torque required to pump the refrigerant at different refrigerant temperatures at the inlet, allowing the refrigerant to flow smoothly in the refrigerant circuit, which is beneficial for the refrigeration equipment to achieve its refrigeration function smoothly.

[0092] The third temperature detection unit 63 detects the third refrigerant temperature T3 at the outlet of pump 1. Based on the third refrigerant temperature T3, it can be determined whether the refrigerant temperature at the pump outlet meets the refrigerant requirement temperature T4 required by the cooling equipment 2. Based on the difference between the two, the third refrigerant temperature T3 is adjusted to meet the required refrigerant requirement temperature T4.

[0093] The ambient temperature T0 of the environment in which the refrigerant circuit is located is detected by the fourth temperature detection unit 64. When the refrigeration equipment is stopped and restarted, the temperature of the refrigerant at each position in the refrigerant circuit can be known based on the ambient temperature T0. Thus, the appropriate heating power of the electric heating device 4 can be selected based on the ambient temperature T0, thereby determining the required number of electric heating units.

[0094] like Figure 3 As shown, a second aspect of this application provides a control method for a refrigeration device according to a first aspect of this application, comprising: determining the number of electric heating units to be turned on based on temperature information characterizing the temperature of the refrigerant at at least one location in the refrigerant circuit and / or the ambient temperature of the refrigerant circuit; and turning on the required number of electric heating units.

[0095] The control method of the refrigeration equipment in this application embodiment has the same advantages as the refrigeration equipment in this application embodiment.

[0096] In some embodiments of the control method, the temperature information includes: a first refrigerant temperature T1 in the refrigerant pipeline 5 between the heat exchanger 3 and the electric heating device 4; and / or a second refrigerant temperature T2 at the inlet of the pump 1; and / or a third refrigerant temperature T3 at the outlet of the pump 1; and / or the ambient temperature T0 of the environment in which the refrigerant circuit is located.

[0097] The advantages of the temperature information, including the first refrigerant temperature T1, the second refrigerant temperature T2, the third refrigerant temperature T3, and the ambient temperature T0, can be found in the relevant descriptions of each temperature detection unit in the temperature detection device 6.

[0098] In some embodiments of the control method, activating the required number of electric heating units includes: preferentially activating the required number of electric heating units closer to the inlet of pump 1; or preferentially activating the required number of electric heating units with shorter usage time.

[0099] Prioritize activating the required number of electric heating units closer to the inlet of pump 1. This allows the heated refrigerant to enter the pump promptly, preventing heat loss during its flow to the pump and ensuring the refrigerant passes through the pump at a suitable temperature.

[0100] Prioritizing the activation of the required number of electric heating units with shorter usage times helps to make the usage time of each electric heating unit as close as possible, thereby maximizing the lifespan of each electric heating unit and maintaining a high level of reliability for the electric heating device.

[0101] Of course, in order to achieve a suitable temperature for the refrigerant at the pump inlet, in embodiments not shown, a number of electric heating units may be randomly activated as needed.

[0102] In some embodiments of the control method, the control method includes: determining the number of electric heating units to be turned on before the pump 1 is turned on; and turning on the pump 1 after a predetermined time period of turning on the required number of electric heating units.

[0103] The above settings ensure that the refrigerant pumped when the pump is turned on has been heated to a certain extent, which facilitates the smooth pumping of the refrigerant by pump 1 and enables the refrigeration equipment to start its refrigeration function smoothly.

[0104] In some embodiments of the control method, pump 1 is a variable frequency pump, and the control method includes: if T2 < high frequency start preset temperature, the variable frequency pump starts at a high frequency higher than the normal start frequency; if T2 ≥ high frequency start preset temperature, the variable frequency pump starts at the normal start frequency, wherein T2 is the second refrigerant temperature of the refrigerant at the inlet of pump 1; wherein T2 is the second refrigerant temperature of the refrigerant at the inlet of pump 1.

[0105] The starting frequency of the variable frequency pump is determined by comparing T2 with the preset high-frequency start-up temperature. This allows for the appropriate setting of the starting torque of pump 1 based on the performance of the refrigerant at the corresponding temperature, such as viscosity, thereby facilitating the smooth pumping of the refrigerant.

[0106] In some implementations of the control method, -45℃ ≤ high-frequency start-up preset temperature ≤ -10℃. For example, the high-frequency start-up preset temperature can be -10℃, -15℃, -25℃, -30℃, -40℃, etc. It is not recommended to power on the system when the temperature is below -45℃.

[0107] The above range of preset high-frequency start-up temperatures is illustrative. The preset high-frequency start-up temperature can be determined based on the pump characteristics selected for different product models.

[0108] In some embodiments of the control method, the temperature information includes a first refrigerant temperature T1. The lower the first refrigerant temperature T1, the more electric heating units need to be turned on.

[0109] The number of electric heating units to be turned on is determined based on the first refrigerant temperature T1, which ensures that the heated refrigerant is in a suitable temperature range when it reaches the pump inlet, thus facilitating smooth pumping of the refrigerant.

[0110] In some embodiments of the control method, the electric heating device 4 includes four electric heating units, and the control method includes:

[0111] When T1 ≤ the first preset heating temperature, four electric heating units are turned on. After the four electric heating units are turned on for a first preset time period, pump 1 is started. T1 is the first refrigerant temperature in the refrigerant pipeline 5 between heat exchanger 3 and electric heating device 4.

[0112] When the first preset heating temperature < T1 ≤ the second preset heating temperature, the three electric heating units are turned on. After the three electric heating units have been turned on for the second preset time period, pump 1 is started.

[0113] When the second preset heating temperature < T1 ≤ the third preset heating temperature, the two electric heating units are turned on. After the two electric heating units have been turned on for the third preset time period, pump 1 is started.

[0114] When the third preset heating temperature < T1 ≤ the fourth preset heating temperature, two electric heating units are turned on. After the two electric heating units have been turned on for the fourth preset time period, pump 1 is started. Alternatively, one electric heating unit is turned on. After the one electric heating unit has been turned on for the fifth preset time period, pump 1 is started. The fifth preset time period is longer than the fourth preset time period.

[0115] The number of activated electric heating units in the electric heating device 4 is matched with the temperature range of the first refrigerant temperature T1. This allows the refrigeration equipment to be adapted to various low-temperature environments, improving its environmental adaptability and reliability. It also simplifies the control process.

[0116] In some embodiments of the control method, when the fourth preset heating temperature is less than T1, if T3 is less than T4, at least one electric heating unit is turned on; if T3 is greater than or equal to T4, the electric heating device 4 is turned off. Here, T3 is the third refrigerant temperature at the outlet of pump 1, and T4 is the required refrigerant temperature for the cooling equipment 2. When T3 is less than T4, for example, one or two electric heating units can be turned on.

[0117] Based on the comparison between the third refrigerant temperature T3 and the refrigerant demand temperature T4, it is determined that the electric heating unit is turned on, which facilitates the use of the electric heating device 4 to ensure that the third refrigerant temperature T3 at the pump outlet meets the refrigerant demand temperature T4.

[0118] In some embodiments of the control method, -45℃ ≤ first preset heating temperature ≤ -40℃; and / or 15s ≤ first preset time period ≤ 30s; and / or -40℃ < second preset heating temperature ≤ -30℃; and / or 15s ≤ second preset time period ≤ 30s; and / or -30℃ < third preset heating temperature ≤ -20℃; and / or 15s ≤ third preset time period ≤ 30s; -20℃ < fourth preset heating temperature ≤ -10℃; and / or 5s ≤ second preset time period ≤ 15s; and / or 15s ≤ fifth preset time period ≤ 30s. The difference between any two adjacent preset heating temperatures (first, second, third, and fourth) is within the range of 5℃ to 15℃.

[0119] By reasonably setting the first to fourth preset heating temperatures and the first to fifth preset heating time periods, the refrigerants at different temperatures can reach the pump's temperature requirements after being heated by the electric heating device 4, thus facilitating the smooth pumping of the refrigerant.

[0120] The first to fourth preset heating temperatures and the first to fifth preset heating time periods mentioned above are exemplary. The first to fourth preset heating temperatures and the first to fifth preset heating time periods can be determined, for example, based on the physical properties of the refrigerant.

[0121] In some embodiments of the control method, pump 1 is a variable frequency pump, and the control method includes: if T1 ≤ fourth preset heating temperature, starting pump 1 includes starting the variable frequency pump at a high frequency higher than the normal starting frequency, and after the variable frequency pump is started, it runs at a high frequency or at a frequency lower than the high frequency.

[0122] When the initial refrigerant temperature T1 is low, the pump is started at a higher frequency to give it a higher starting torque, so that the refrigerant can be pumped smoothly even if the refrigerant heating is not ideal.

[0123] In some embodiments of the control method, during the operation of the refrigeration equipment, if the load of the refrigeration equipment drops to a minimum and T1 < T4, at least one electric heating unit is activated until T3 ≥ T4, where T3 is the third refrigerant temperature at the outlet of pump 1, and T4 is the refrigerant temperature required by the refrigeration equipment 2. When T3 < T4, for example, one or two electric heating units may be activated.

[0124] During the operation of the refrigeration equipment, the electric heating device 4 participates in the temperature regulation of the third refrigerant, which helps to broaden the operating range of the refrigeration equipment and improve the user experience.

[0125] The following provides a detailed description of the refrigeration equipment and its control method according to embodiments of this application.

[0126] like Figure 1 As shown, the refrigeration equipment includes a refrigerant circulation system, a secondary refrigerant circulation system, a temperature detection device 6, and a control device 7.

[0127] The refrigerant cycle system includes a heat exchanger 3, which is used for heat exchange between the refrigerant and the secondary refrigerant. The refrigeration cycle system may include a compressor, a condenser, a throttling device, and an evaporator connected sequentially through refrigerant piping. The heat exchanger 3 is the evaporator of the refrigeration cycle system.

[0128] like Figure 1 As shown, the refrigerant circulation system includes a pump 1, a refrigerant pipeline 5, and an electric heating device 4. The pump 1 is a variable frequency pump. The refrigerant pipeline 5 sequentially connects the outlet of pump 1, the refrigerated equipment 2, the heat exchanger 3, and the inlet of pump 1 to form a refrigerant loop. The electric heating device 4 is configured to heat the refrigerant within the refrigerant pipeline 5 between the heat exchanger 3 and the inlet of pump 1. The electric heating device 4 includes two or more electric heating units that can be started and stopped independently of each other.

[0129] The refrigeration equipment is a water chiller unit, and the user load is the cooling equipment 2. The refrigerant that exchanges heat with the evaporator of the refrigeration equipment is supplied to the user load via pump 1 to meet its cooling needs. The required temperature of the refrigerant for the user load 2 is, for example, between 7℃ and 28℃, but the required temperature varies depending on the specific user load 2. The refrigerant is an ethylene glycol solution. The refrigeration equipment can generally operate at a minimum temperature of -40℃.

[0130] The viscosity of the refrigerant ethylene glycol gradually increases as the ambient temperature decreases, resulting in poorer fluidity. This increases the load required to pump the refrigerant and reduces reliability. During normal operation of the refrigeration equipment 2, the refrigerant ethylene glycol maintains a high temperature and good fluidity, eliminating any potential operational risks to the pump. The refrigeration equipment and its control method in this application primarily address the refrigerant temperature control during startup in ultra-low temperature environments.

[0131] The electric heating device 4 in this embodiment has four electric heating units, namely the first to the fourth electric heating units 41 to 44. In embodiments not shown, the electric heating device 4 may include more or fewer electric heating units. In this embodiment, the electric heating device 4 is arranged near the pump inlet, within 0.5 meters of the pump inlet, that is, the distance between the end of the electric heating device 4 closest to the pump inlet and the pump inlet is within 0.5 meters, for example, 0.4 meters.

[0132] The temperature detection device 6 includes a first temperature detection unit 61, a second temperature detection unit 62, a third temperature detection unit 63, and a fourth temperature detection unit 64. The four temperature detection units respectively detect the first refrigerant temperature T1 in the refrigerant pipeline 5 between the heat exchanger 3 and the electric heating device 4, the second refrigerant temperature T2 at the inlet of the pump 1, the third refrigerant temperature T3 at the outlet of the pump 1, and the ambient temperature T0 of the environment in which the refrigerant circuit is located.

[0133] When the refrigeration equipment is started, the refrigerant temperature at all points in the refrigerant circuit is the same as the ambient temperature. At this time, T1 = T2 = T3 = ambient temperature T0. After the control device 7 issues the start-up command, it operates through the following control method:

[0134] When T1 ≤ -40℃, all four electric heating units are fully operational. After 15–30 seconds of operation, the variable frequency pump is started. At this time, the pump starts at a higher frequency than usual to overcome the resistance of the low-temperature refrigerant between the fourth electric heating unit 44 and the pump's internal cavity through a larger starting torque. The refrigerant is heated step-by-step through the first to fourth electric heating units 41–44, and by the time it enters the variable frequency pump, the second refrigerant temperature T2 has risen to approximately -10℃, significantly reducing the refrigerant's flow resistance. After the variable frequency pump starts, the frequency can be appropriately reduced or maintained at a high operating frequency.

[0135] When -40℃ < T1 ≤ -30℃, turn on the second electric heating unit 42 to the fourth electric heating unit 44. After 15-30 seconds of operation, start the variable frequency pump. At this time, the variable frequency pump starts at a higher frequency than the normal starting frequency to overcome the low-temperature refrigerant resistance between the fourth electric heating unit 44 and the pump's internal cavity through a larger starting torque. The refrigerant is heated step by step through the second to fourth electric heating units 42-44, and when it enters the variable frequency pump, the temperature of the second refrigerant T2 rises to about -10℃, which can significantly reduce the flow resistance of the refrigerant. After the variable frequency pump is turned on, the frequency can be appropriately reduced or maintained at the high-frequency starting frequency.

[0136] When -30℃ < T1 ≤ -20℃, turn on the third and fourth electric heating units 43 and 44. After 15–30 seconds of operation, start the variable frequency pump. At this time, the variable frequency pump starts at a higher frequency than the normal starting frequency to overcome the low-temperature refrigerant resistance between the fourth electric heating unit 44 and the pump's internal cavity through a larger starting torque. The refrigerant is heated step-by-step through the third and fourth electric heating units 43 and 44, and when it enters the variable frequency pump, the second refrigerant temperature T2 rises to approximately -10℃, significantly reducing the refrigerant's flow resistance. After the variable frequency pump starts, the frequency can be appropriately reduced or maintained at a high starting frequency.

[0137] When -20℃ < T1 ≤ -10℃, turn on the third and fourth electric heating units 43 and 44 for 0–15 seconds, then start the variable frequency pump; alternatively, only the fourth electric heating unit 44 can be turned on for 15–30 seconds before starting the variable frequency pump. When starting the variable frequency pump, a higher starting frequency than the conventional starting frequency is used to overcome the low-temperature refrigerant resistance between the fourth electric heating unit 44 and the pump's internal cavity with a larger starting torque. After the refrigerant is heated stepwise by the third and fourth electric heating units 43 and 44, or heated by the fourth electric heating unit 44, the second refrigerant temperature T2 rises to approximately -10℃ when entering the variable frequency pump, significantly reducing the refrigerant's flow resistance. After the variable frequency pump is started, the frequency can be appropriately reduced or maintained at a high starting frequency.

[0138] When -10℃ < T1, the electric heating device can be controlled by the temperature of the third refrigerant. When T3 < the required refrigerant temperature T4, one or two electric heating units can be turned on, with priority given to the unit with the shorter operating time. When T3 ≥ the required refrigerant temperature T4, all electric heating units will not be turned on.

[0139] In this embodiment, when T2 < -10℃, the variable frequency pump is started at a higher frequency than the normal start-up frequency. When T2 ≥ -10℃, the variable frequency pump is started at the normal start-up frequency. For example, the required start-up frequency for the variable frequency pump during normal startup is 30Hz, which is the normal start-up frequency. However, when T2 < -10℃, the variable frequency pump can be started at a higher frequency, such as 50Hz, 65Hz, or 80Hz, which is greater than 30Hz.

[0140] After the refrigeration equipment is operating normally, the first refrigerant temperature T1 is the refrigerant output temperature of the refrigeration equipment. When the load of the refrigeration equipment is reduced to the point where it cannot be reduced further, if the first refrigerant temperature T1 is still lower than the refrigerant demand temperature T4 required by the refrigeration equipment 2, at least some of the electric heating units of the electric heating device 4 can be turned on. For example, one or two electric heating units can be turned on, or the corresponding electric heating units of the electric heating device 4 can be turned on in segments according to the first refrigerant temperature T1, as mentioned above, until T3 ≥ T4, so that the third refrigerant temperature T3 at the pump outlet meets the refrigerant demand temperature T4. Using the electric heating device 4 to assist in adjusting the third refrigerant temperature T3 during normal operation of the refrigeration equipment helps to broaden the operating range of the refrigeration equipment and improve the user experience.

[0141] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and not to limit them; although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of this application or equivalent substitutions can be made to some technical features, all of which should be covered within the scope of the technical solutions claimed in this application.

Claims

1. A refrigeration device, characterized in that, The system includes a refrigerant circulation system and a secondary refrigerant circulation system. The refrigerant circulation system includes a heat exchanger (3) for exchanging heat between the refrigerant and the secondary refrigerant. The secondary refrigerant circulation system includes: Pump (1); A refrigerant pipeline (5) is sequentially connected to the outlet of the pump (1), the refrigeration equipment (2), the heat exchanger (3), and the inlet of the pump (1) to form a refrigerant circuit; and An electric heating device (4) is configured to heat the refrigerant in the refrigerant pipeline (5) between the heat exchanger (3) and the inlet of the pump (1). The electric heating device (4) includes two or more electric heating units that are independently started and stopped and arranged sequentially along the refrigerant pipeline (5).

2. The refrigeration equipment according to claim 1, characterized in that, The electric heating device (4) includes four electric heating units.

3. The refrigeration equipment according to claim 1, characterized in that, The distance between the electric heating device and the inlet of the pump (1) is less than or equal to 0.5 meters.

4. The refrigeration equipment according to claim 1, characterized in that, The pump (1) is a variable frequency pump; and / or The refrigerant includes ethylene glycol.

5. The refrigeration equipment according to any one of claims 1 to 4, characterized in that, include: Temperature detection device (6) is configured to acquire temperature information characterizing the temperature of the refrigerant at at least one location in the refrigerant circuit and / or the ambient temperature of the refrigerant circuit. and The control device (7) is signal-connected to the temperature detection device (6) and the electric heating device (4) and is configured to control the start and stop of the two or more electric heating units according to the temperature information detected by the temperature detection device (6).

6. The refrigeration equipment according to claim 5, characterized in that, The temperature detection device (6) includes: A first temperature detection unit (61) is configured to detect a first refrigerant temperature T1 in the refrigerant pipeline (5) between the heat exchanger (3) and the electric heating device (4), the temperature information including the first refrigerant temperature T1; and / or The second temperature detection unit (62) is configured to detect the second refrigerant temperature T2 at the inlet of the pump (1), the temperature information including the second refrigerant temperature T2; and / or The third temperature detection unit (63) is configured to detect the third refrigerant temperature T3 at the outlet of the pump (1), the temperature information including the third refrigerant temperature T3; and / or The fourth temperature detection unit (64) is configured to detect the ambient temperature T0 of the environment in which the refrigerant circuit is located, and the temperature information includes the ambient temperature T0.

7. A control method for a refrigeration device according to any one of claims 1 to 6, characterized in that, include: The number of electric heating units to be turned on is determined based on temperature information characterizing the temperature of the refrigerant at at least one location in the refrigerant circuit and / or the ambient temperature of the refrigerant circuit. and Turn on the required number of the electric heating units.

8. The control method according to claim 7, characterized in that, The temperature information includes: The first refrigerant temperature T1 of the refrigerant in the refrigerant pipeline (5) between the heat exchanger (3) and the electric heating device (4); and / or The second refrigerant temperature T2 at the inlet of the pump (1); and / or The third refrigerant temperature T3 at the outlet of the pump (1); and / or The ambient temperature T0 is the environment in which the refrigerant circuit is located.

9. The control method according to claim 7, characterized in that, Turning on the required number of the electric heating units includes: Prioritize activating the required number of the electric heating units closer to the inlet of the pump (1); or Prioritize activating the required number of electric heating units with shorter usage times.

10. The control method according to claim 7, characterized in that, include Before the pump (1) is turned on, determine the number of electric heating units that need to be turned on; and The pump (1) is turned on after a predetermined time period following the activation of the required number of the electric heating units.

11. The control method according to claim 10, characterized in that, The pump (1) is a variable frequency pump, and the control method includes: If T2 < high-frequency start preset temperature, the variable frequency pump starts at a high-frequency start frequency higher than the normal start frequency. If T2 ≥ high frequency start preset temperature, the variable frequency pump starts at normal start frequency, where T2 is the second refrigerant temperature of the refrigerant at the inlet of the pump (1); Where T2 is the second refrigerant temperature at the inlet of the pump (1).

12. The control method according to claim 11, characterized in that, -45℃≤High-frequency start preset temperature≤-10℃.

13. The control method according to claim 8, characterized in that, The temperature information includes the first refrigerant temperature T1. The lower the first refrigerant temperature T1, the more electric heating units need to be turned on.

14. The control method according to claim 13, characterized in that, The electric heating device (4) includes four electric heating units, and the control method includes: When T1 ≤ the first preset heating temperature, the four electric heating units are turned on. After the four electric heating units are turned on for a first preset time period, the pump (1) is started. T1 is the first refrigerant temperature in the refrigerant pipeline (5) between the heat exchanger (3) and the electric heating device (4). When the first preset heating temperature < T1 ≤ the second preset heating temperature, the three electric heating units are turned on. After the three electric heating units are turned on for a second preset time period, the pump (1) is started. When the second preset heating temperature < T1 ≤ the third preset heating temperature, the two electric heating units are turned on. After the two electric heating units are turned on for a third preset time period, the pump (1) is started. When the third preset heating temperature < T1 ≤ the fourth preset heating temperature, two of the electric heating units are turned on. After the two electric heating units are turned on for the fourth preset time period, the pump (1) is started. Alternatively, one electric heating unit is turned on. After the one electric heating unit is turned on for the fifth preset time period, the pump (1) is started. The fifth preset time period is longer than the fourth preset time period.

15. The control method according to claim 14, characterized in that, When the fourth preset heating temperature is <T1, if T3 < T4, at least one of the electric heating units is turned on, and if T3 ≥ T4, the electric heating device (4) is in the off state, where T3 is the third refrigerant temperature at the outlet of the pump (1), and T4 is the refrigerant required temperature of the cooling equipment (2).

16. The control method according to claim 14, characterized in that, -45℃≤First preset heating temperature≤-40℃; and / or 15s ≤ first preset time period ≤ 30s; and / or -40℃ < second preset heating temperature ≤ -30℃; and / or 15s ≤ second preset time period ≤ 30s; and / or -30℃ < third preset heating temperature ≤ -20℃; and / or 15s ≤ third preset time period ≤ 30s; -20℃ < fourth preset heating temperature ≤ -10℃; and / or 5s ≤ second preset time period ≤ 15s; and / or 15s ≤ Fifth preset time period ≤ 30s; The difference between any two adjacent preset heating temperatures (the first, second, third, and fourth preset heating temperatures) is within the range of 5°C to 15°C.

17. The control method according to claim 14, characterized in that, The pump (1) is a variable frequency pump, and the control method includes: If T1 ≤ the fourth preset heating temperature, the pump (1) is started, including the variable frequency pump, which is started at a high frequency higher than the normal start frequency. After the variable frequency pump is started, it runs at the high frequency or at a frequency lower than the high frequency.

18. The control method according to any one of claims 8 to 17, characterized in that, During the operation of the refrigeration equipment, if the load of the refrigeration equipment drops to the minimum and T1 < T4, at least one of the electric heating units is turned on until T3 ≥ T4, where T3 is the third refrigerant temperature at the outlet of the pump (1) and T4 is the refrigerant required temperature of the cooling equipment (2).

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