Refrigeration and cold accumulation control method of refrigerant circulation system, refrigerant circulation system and air conditioning unit

Abstract

The invention discloses a control method for refrigeration and cold accumulation of a refrigerant circulation system and the refrigerant circulation system. The control method comprises the steps that a, the refrigeration target evaporation temperature T1 of an indoor unit and the target cold accumulation temperature T2 of a cold accumulation device are obtained; step b, enabling the evaporation temperature of the indoor unit to reach T1 and enabling the temperature of a cold storage medium of the cold storage device to reach T2: step b1, obtaining the current temperature T0 of the cold storage medium, and calculating a difference value t between T0 and T1; according to the t, the refrigeration calculation target evaporation temperature Ta of the indoor unit and the cold storage calculation target temperature Tb of the cold storage device are determined; the refrigeration capacity demand Q1 needed by the indoor unit is determined, and the refrigeration capacity demand Q2 of the cold storage device is determined; the sum Q total of the Q1 and the Q2 is calculated, and the working state of the compressor unit is adjusted according to the Q total; and b2, judging whether T0 reaches T2 or not, and if not, repeating the step b1. According to the control method and the energy-saving method, the applied refrigerant circulation system relates to an energy-saving heat exchange device, and the energy-saving effect is achieved.

Description

Technical Field

[0001] This invention relates to the field of air conditioning technology, and particularly to a control method for simultaneous cooling and cold storage in a refrigerant circulation system, a refrigerant circulation system, and an air conditioning unit. Background Technology

[0002] Currently, most regions in my country have adopted peak-valley electricity pricing policies, which implement differentiated electricity price standards based on different electricity consumption periods to encourage users to use electricity during off-peak hours and alleviate peak-hour pressure on the power grid.

[0003] However, conventional air conditioning systems do not have the function of transferring electricity generated during off-peak hours to peak hours. Therefore, energy storage devices are needed to achieve this transfer of electricity.

[0004] After adding energy storage equipment, when the energy storage equipment and the air conditioning terminal cooling demand are turned on at the same time, if the cooling effect of the energy storage equipment is to be ensured, the cooling of the indoor terminal needs to be stopped during the off-peak electricity consumption period, which will sacrifice the cooling effect on the environment; if the cooling effect on the environment is to be unaffected, it is difficult to guarantee the cooling effect of the energy storage equipment. Summary of the Invention

[0005] The purpose of this invention is to provide a control method for refrigeration and cold storage in a highly efficient refrigerant circulation system, and a refrigerant circulation system using this method.

[0006] The first aspect of this invention discloses a control method for simultaneous cooling and cold storage in a refrigerant circulation system. The refrigerant circulation system includes a condenser, a compressor unit, an indoor unit disposed between the condenser and the compressor unit, and a cold storage device. The cold storage device is used to absorb and store the cold energy of the refrigerant passing through it. The compressor unit includes a first compressor and a second compressor. The compressor unit's operating modes include a single-unit operating mode with one compressor and a multi-unit operating mode with multiple compressors. The control method for simultaneous cooling and cold storage includes: Step a: In response to the user's temperature setting, obtain the target evaporation temperature T1 of the indoor unit and the target cold storage temperature T2 of the cold storage device; Step b, adjusting the compressor unit to bring the evaporation temperature of the indoor unit to T1 and the temperature of the cold storage medium in the cold storage device to T2, includes: Step b1: Obtain the current temperature T0 of the cold storage medium and calculate the difference t between T0 and T1; determine the target evaporation temperature Ta of the indoor unit and the target cold storage temperature Tb of the cold storage device based on t; determine the required cooling capacity Q1 of the indoor unit based on Ta, and the required cooling capacity Q2 of the cold storage device based on T0 and Tb; calculate the sum Q1 and Q2 Qtotal, and adjust the operating state of the compressor unit based on whether Qtotal falls within the high energy efficiency range of the compressor unit's single-unit operating mode and whether it falls within the high energy efficiency range of the multi-unit operating mode; Step b2: Determine whether T0 has reached T2. If not, repeat step b1.

[0007] In some embodiments, step b1 includes: when t is greater than a first threshold t1, using the cooling target evaporation temperature T1 as the cooling calculation target evaporation temperature Ta of the indoor unit and the cold storage calculation target temperature Tb of the cold storage device.

[0008] In some embodiments, step b1 includes: when t is less than the first threshold t1 and T0 is greater than T2, the target cold storage temperature T2 is used as the cold storage calculation target temperature Tb of the cold storage device, and T3 is used as the cooling calculation target evaporation temperature Ta of the indoor unit. T3 is calculated by the following formula: T3=T1-k(T1-T2), where k is an adjustment coefficient, and k is greater than 0 and less than 1.

[0009] In some embodiments, step b1 further includes: when the current temperature T0 of the cold storage medium reaches T2, shutting off the connection between the cold storage device and the condenser and the compressor unit, and using the target evaporation temperature T1 as the target evaporation temperature Ta for the indoor unit's cooling calculation.

[0010] In some embodiments, step b1 includes: determining the cooling capacity requirement Q2 of the cold storage device based on T0 and Tb, combined with the specific heat capacity, mass, and preset change time of the cold storage medium.

[0011] In some embodiments, the high-efficiency range of the first compressor is (Qx1, Qx2), and the high-efficiency range of the second compressor is (Qy1, Qy2). The single-compressor working mode includes the first-compressor working mode and the second-compressor working mode, and the multi-compressor working mode includes the co-working mode of the first compressor and the second compressor. In the co-working mode of the first compressor and the second compressor, the inlets of the first compressor and the second compressor are connected. The refrigerant output by the indoor unit and the refrigerant output after heat exchange with the cold storage device are combined and then sent to the inlets of the first compressor and the second compressor. Step b1 includes: when Qx1 < Qtotal < Qx2, adjusting the working mode of the compressor unit to the first-compressor working mode; when Qy1 < Qtotal < Qy2, adjusting the working mode of the compressor unit to the second-compressor working mode; when (Qx1 + Qy1) < Qtotal < (Qx2 + Qy2), adjusting the working mode of the compressor unit to the co-working mode of the first compressor and the second compressor.

[0012] In some embodiments, the multi-compressor working mode further includes the independent working mode of the first compressor and the second compressor. In the independent working mode of the first compressor and the second compressor, the inlets of the first compressor and the second compressor are not connected. The refrigerant output by the indoor unit and the refrigerant output after heat exchange with the cold storage device are not combined and are separately sent to the inlets of the first compressor and the second compressor. Step b1 includes: when none of the three inequalities Qx1 < Qtotal < Qx2, Qy1 < Qtotal < Qy2, and (Qx1 + Qy1) < Qtotal < (Qx2 + Qy2) holds, adjusting the working mode of the compressor unit to the independent working mode of the first compressor and the second compressor.

[0013] The second aspect of the present invention discloses a refrigerant circulation system that applies any of the above-mentioned control methods for simultaneous refrigeration and cold storage, including: a condenser, a compressor unit, an indoor unit and a cold storage device provided between the condenser and the compressor unit. The cold storage device is used to absorb and store the cold of the refrigerant passing through it; the compressor unit includes a first compressor and a second compressor, and the working mode of the compressor unit includes a single-compressor working mode with one compressor working and a multi-compressor working mode with multiple compressors working.

[0014] In some embodiments, the multi-compressor working mode includes the co-working mode of the first compressor and the second compressor. In the co-working mode of the first compressor and the second compressor, the inlets of the first compressor and the second compressor are connected. The refrigerant output by the indoor unit and the refrigerant output after heat exchange with the cold storage device are combined and then sent to the inlets of the first compressor and the second compressor.

[0015] In some embodiments, the multi-unit operating mode includes an independent operating mode for the first compressor and the second compressor. In the independent operating mode of the first compressor and the second compressor, the inlets of the first compressor and the second compressor are not connected, and the refrigerant output by the indoor unit and the refrigerant output after heat exchange with the cold storage device do not merge, but are independently sent to the inlet of the first compressor and the inlet of the second compressor, respectively.

[0016] A third aspect of the present invention discloses an air conditioning unit, including the above-described refrigerant circulation system.

[0017] The control method for simultaneous cooling and cold storage in a refrigerant circulation system provided by this invention, by setting the compressor unit to have single-unit and multi-unit operating modes, and by determining the target evaporation temperature Ta of the indoor unit and the target cold storage temperature Tb of the cold storage device, and based on these, determining the sum Qtotal of the required cooling capacity Q1 for the indoor unit and the required cooling capacity Q2 for the cold storage device, and by determining whether Qtotal falls within the high-efficiency range of the compressor unit in single-unit and multi-unit operating modes, the operating state of the compressor unit is adjusted. This enables the refrigerant circulation system to simultaneously perform cooling and cold storage, ensuring both cooling and cold storage effects are reliably achieved, and maintaining a high-efficiency operating state of the compressor unit during the process, thus improving the energy-saving effect of the refrigerant circulation system. The energy-saving control method of this invention involves an energy-saving heat exchange device in the refrigerant circulation system, achieving energy-saving performance.

[0018] Other features and advantages of the invention will become clear from the following detailed description of exemplary embodiments of the invention with reference to the accompanying drawings. Attached Figure Description

[0019] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the refrigerant circulation system according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the refrigerant circulation system in the independent operating mode of the first compressor and the second compressor according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the refrigerant circulation system in the first compressor operating mode according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the refrigerant circulation system in the second compressor operating mode according to an embodiment of the present invention; Figure 5This is a schematic diagram of the refrigerant circulation system in the working mode of the first compressor and the second compressor in an embodiment of the present invention. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. 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 figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0022] In the description of this invention, 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 invention.

[0023] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0024] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0025] like Figures 1 to 5 As shown, the refrigerant circulation system of this embodiment includes a condenser 108, a compressor unit, an indoor unit 2 disposed between the condenser 108 and the compressor unit, and a cold storage device 310. In the embodiment shown, the cold storage device 310 is disposed in the cold storage device 3. The indoor unit 2 includes multiple indoor heat exchangers 204 and corresponding indoor unit control valves 203 disposed before each indoor heat exchanger 204. The inlet of the indoor unit 2 is connected to the cold storage device 3 through the indoor unit liquid pipe main 201 and the second liquid pipe 303. The cold storage device 3 is connected to the condenser through the first liquid pipe 301, the outdoor unit liquid pipe 101, and the outdoor control valve 109. The outlet of the indoor unit 2 is connected to the cold storage device 3 through the indoor unit gas pipe main 202 and the second gas pipe 304. The cold storage device 3 is connected to the compressor unit through the first gas pipe 302, the outdoor unit gas pipe 102, and the four-way valve 107.

[0026] The cold storage device 310 is used to absorb and store the cold energy of the refrigerant passing through it. During cold storage operation, the compressor unit of the refrigerant circulation system compresses the refrigerant and sends it to the condenser 108 for condensation. After being condensed in the condenser 108, the refrigerant passes through the expansion valve and becomes a low-temperature, low-pressure refrigerant. The low-temperature, low-pressure refrigerant flows into the heat exchange pipe of the cold storage device 310 to exchange heat with the cold storage medium in the cold storage device 310. The cold storage medium absorbs and stores the cold energy of the refrigerant.

[0027] The compressor unit includes a first compressor 105 and a second compressor 106. The compressor unit can operate in two modes: a single-unit mode where one compressor operates and a multi-unit mode where multiple compressors operate. In single-unit mode, only one compressor compresses the refrigerant, for example, either the first compressor 105 or the second compressor 106. In multi-unit mode, multiple compressors operate simultaneously to compress the refrigerant.

[0028] The control method for simultaneous refrigeration and cold storage in a refrigerant circulation system includes steps a and b.

[0029] Step a, in response to the user's temperature setting, obtain the target evaporation temperature T1 of the indoor unit 2 and the target cold storage temperature T2 of the cold storage device 310.

[0030] The target cold storage temperature T2 of the cold storage device 310 is the desired temperature of the cold storage medium in the cold storage state. That is, it is the temperature of the cold storage medium when the cold storage device 310 has absorbed all the cold energy from the refrigerant and no longer absorbs any more, maintaining the cold storage state. It reflects the amount of cold energy stored by the cold storage device; the lower the temperature, the more cold energy is stored. The user's temperature setting includes setting the cooling temperature, such as setting the indoor ambient temperature. In some refrigerant circulation systems that allow users to set the temperature of the cold storage medium, the user's temperature setting may also include setting the temperature of the cold storage medium in the cold storage state, i.e., setting the target cold storage temperature T2. In some embodiments, the refrigerant circulation system does not allow users to set the temperature of the cold storage medium. In this case, when cold storage is started, the target cold storage temperature of the cold storage device 310 is preset in the refrigerant circulation system, or calculated by the refrigerant circulation system based on the current indoor and / or outdoor ambient temperatures. The target evaporation temperature T1 of indoor unit 2 is the evaporation temperature of the refrigerant in the indoor unit calculated by the refrigerant circulation system to maintain the indoor environment stably at the indoor ambient temperature set by the user.

[0031] For example, if the indoor unit is located in an indoor environment with a temperature of 25 degrees Celsius, and the user sets the indoor environment temperature to 20 degrees Celsius, the refrigerant circulation system has a range of applicable indoor environments. After the user sets the indoor environment temperature to 20 degrees Celsius, the refrigerant circulation system calculates, based on the approximate size of the indoor environment and the outdoor temperature, that the refrigerant evaporation temperature of the indoor unit needs to be 10 degrees Celsius to maintain the indoor environment temperature at 20 degrees Celsius. Therefore, the target evaporation temperature T1 of the indoor unit 2 is 10 degrees Celsius. The target cold storage temperature T2 of the cold storage device 310 is usually lower, such as 1 degree Celsius, -2 degrees Celsius, or -5 degrees Celsius.

[0032] Step b, adjusting the compressor unit to make the evaporation temperature of the refrigerant in the indoor unit 2 reach T1 and the temperature of the cold storage medium in the cold storage device 310 reach T2, specifically includes steps b1 and b2.

[0033] Adjusting the compressor unit includes changing its power and operating mode, ultimately achieving a cold storage medium temperature of T2, completing the cold storage equipment's cold storage, and ensuring the refrigerant evaporation temperature of indoor unit 2 reaches T1, thus maintaining the indoor environment at the user's set temperature.

[0034] Step b1: Obtain the current temperature T0 of the cold storage medium. In the embodiment shown in the figure, a cold storage medium temperature sensor 3105 is used to detect the temperature of the cold storage medium, and then the difference t between T0 and T1 is calculated. Based on t, the target evaporation temperature Ta for cooling calculation of indoor unit 2 and the target cold storage temperature Tb for cold storage device 310 are determined. The target evaporation temperature Ta for cooling calculation of indoor unit 2 and the target cold storage temperature Tb for cold storage device 310 refer to the target evaporation temperature during the setting process of the refrigerant of indoor unit 2 and the target temperature during the setting process of the cold storage medium of cold storage device 310, respectively, before the final goal of achieving the target evaporation temperature T1 of the refrigerant in indoor unit 2 and the target temperature T2 of the cold storage medium in cold storage device 310 are achieved. After obtaining the current temperature T0 of the cold storage medium, the difference t between T0 and T1 is calculated. t reflects the current temperature of the cold storage medium and the magnitude of the target evaporation temperature of cooling of indoor unit 2, thereby allowing the setting of appropriate target evaporation temperature Ta and target cold storage temperature Tb for cooling calculation of cold storage device 310.

[0035] Based on Ta, determine the required cooling capacity Q1 for indoor unit 2, and based on T0 and Tb, determine the required cooling capacity Q2 for cold storage device 310; calculate the sum of Q1 and Q2, Q_total, and adjust the operating state of the compressor unit based on whether Q_total falls within the high energy efficiency range of the compressor unit's single-unit operating mode and whether it falls within the high energy efficiency range of the multi-unit operating mode.

[0036] Adjusting the compressor unit's operating status includes adjusting its operating mode and its compression power. After obtaining the target evaporation temperature Ta for refrigeration calculation, the refrigeration capacity requirement Q1 can be calculated. This is the required refrigerant compression capacity of the compressor unit for the indoor unit when maintaining the refrigerant evaporation temperature Ta (i.e., the power used by the compressor unit to maintain the refrigerant evaporation temperature of the indoor unit, without considering the refrigeration capacity requirements of other devices such as cold storage devices). After obtaining Tb, the cooling capacity requirement Q2 of the cold storage device 310 can be calculated. The cooling capacity requirement Q2 of the cold storage device 310 can be calculated by the following method: subtract the cold storage target temperature Tb from the current temperature T0 of the cold storage medium, then multiply by the specific heat capacity and mass of the cold storage medium, then divide by the preset change time, and then multiply by an adjustment coefficient. The result is the cooling capacity requirement Q2 of the cold storage device 310. The value of the adjustment coefficient is related to the value of the cold storage target temperature Tb. The smaller the value of the cold storage target temperature Tb, the larger the value of the adjustment coefficient (that is, the time for the cold storage medium to change from the current temperature T0 to Tb. This change time is calculated by the refrigerant circulation system. For example, it can be calculated based on the temperature difference between the current temperature T0 and the cold storage target temperature Tb. For example, the length of the change time is proportional to the temperature difference). After obtaining Q1 and Q2, calculate the sum of Q1 and Q2, Q_total, and determine whether Q_total falls within the high energy efficiency range of the compressor unit's single-unit operating mode or the high energy efficiency range of the multi-unit operating mode. If it falls within the high energy efficiency range of the compressor unit's single-unit operating mode, adjust the compressor unit's operating mode to single-unit operating mode. If it falls within the high energy efficiency range of the multi-unit operating mode, adjust the compressor unit's operating mode to multi-unit operating mode, and correspondingly adjust the compressor unit to a compression power that matches Q_total.

[0037] Step b2: Determine if T0 has reached T2. If not, repeat step b1. Step b2 follows step b1. After calculating and adjusting the compressor unit's operating mode, the compressor unit starts working, causing the evaporation temperature of indoor unit 2 to decrease. The temperature of the cold storage medium in the cold storage device also decreases. Typically, the target cold storage temperature T2 of the cold storage device 310 is lower than the target evaporation temperature T1 of indoor unit 2. If the temperature T0 of the cold storage medium has not reached T2, step b1 needs to be repeated to continue lowering the temperature of the cold storage medium. Once the temperature T0 of the cold storage medium reaches T2, the connection between the cold storage device and the compressor unit and condenser is usually closed, and then the evaporation temperature of the indoor unit is independently adjusted to reach the target evaporation temperature T1.

[0038] The control method for simultaneous cooling and cold storage in the refrigerant circulation system of this embodiment, by setting the compressor unit to have single-unit and multi-unit operating modes, determines the target evaporation temperature Ta of the indoor unit 2 and the target cold storage temperature Tb of the cold storage device 310, and determines the sum Qtotal of the required cooling capacity Q1 of the indoor unit 2 and the required cooling capacity Q2 of the cold storage device 310, and adjusts the operating state of the compressor unit by judging whether Qtotal falls within the high energy efficiency range of the single-unit operating mode and the high energy efficiency range of the multi-unit operating mode. This enables the refrigerant circulation system to perform cooling and cold storage simultaneously, ensuring the reliable realization of both cooling and cold storage effects, and maintaining a high energy efficiency operating state of the compressor unit during the process, thereby improving the energy-saving effect of the refrigerant circulation system.

[0039] In some embodiments, step b1 includes: when t is greater than a first threshold t1, using the cooling target evaporation temperature T1 as the cooling calculation target evaporation temperature Ta of the indoor unit 2 and the cold storage calculation target temperature Tb of the cold storage device 310. In order to achieve efficient cooling of the cold storage medium of the cold storage device, a minimum temperature difference is set between the refrigerant passing through the cold storage medium and the cold storage medium, that is, the first threshold t1, for example, the first threshold t1 is 1 degree Celsius.

[0040] In this embodiment, the temperature difference between the current temperature T0 of the cold storage medium and the target evaporation temperature T1 of the indoor unit 2 is greater than the first threshold t1. This reflects that the refrigerant, which adjusts the evaporation temperature of the indoor unit with the target evaporation temperature T1 as the target, can effectively ensure the initial cooling of the cold storage medium. At this time, using the target evaporation temperature T1 as the calculated target evaporation temperature Ta of the indoor unit 2 and the calculated target temperature Tb of the cold storage device 310 can effectively adjust the temperature of the cold storage medium while adjusting the evaporation temperature of the indoor unit. This also helps to avoid excessive power increase of the compressor unit, resulting in waste, and the refrigerant circulation system is more energy-efficient and effective.

[0041] In some embodiments, step b1 includes: when t is less than the first threshold t1 and T0 is greater than T2, the target cold storage temperature T2 is used as the cold storage calculation target temperature Tb of the cold storage device 310, and T3 is used as the cooling calculation target evaporation temperature Ta of the indoor unit 2. T3 is calculated by the following formula: T3=T1-k(T1-T2), where k is an adjustment coefficient, which is greater than 0 and less than 1, for example, it can be taken as 0.2~0.5.

[0042] In this embodiment, the temperature difference between the current temperature T0 of the cold storage medium and the target evaporation temperature T1 of the indoor unit 2 is less than the first threshold t1. This indicates that the refrigerant used to adjust the evaporation temperature of the indoor unit with the target evaporation temperature T1 as the target temperature can no longer guarantee the cooling of the cold storage medium. At this time, it is necessary to use the target cold storage temperature T2 as the cold storage calculation target temperature Tb of the cold storage device 310. Correspondingly, the calculated cooling capacity requirement Q2 of the cold storage device will also increase. At the same time, since priority is given to ensuring that the lower cold storage calculation target temperature Tb of the cold storage device 310 is reached, the evaporation temperature of the refrigerant entering the indoor unit will also be lower than the target evaporation temperature T1. Using T3 as the target evaporation temperature Ta of the indoor unit 2 also helps to ensure that the compression power of the compressor unit can effectively guarantee that the cold storage device reaches the cold storage calculation target temperature Tb, so that the cold storage target of the cold storage device is reliably achieved.

[0043] In some embodiments, step b1 further includes: when the current temperature T0 of the cold storage medium reaches T2, shutting off the connection between the cold storage device 310 and the condenser 108 and the compressor unit, and using the cooling target evaporation temperature T1 as the cooling calculation target evaporation temperature Ta of the indoor unit 2.

[0044] In this embodiment, after the cold storage device reaches the target cold storage temperature T2, its connection with other parts of the refrigerant circulation system is closed, so that the refrigerant no longer flows through the cold storage device. At this time, all the refrigerant compressed and driven by the compressor unit is used for the cooling of the indoor unit, which is highly efficient and energy-saving. At this time, the target evaporation temperature T1 is used as the target evaporation temperature Ta for the cooling calculation of the indoor unit 2. The compressor unit can better match the target evaporation temperature T1, so that the indoor unit can reach the target evaporation temperature T1 faster and more efficiently.

[0045] In some embodiments, step b1 includes: determining the cooling capacity requirement Q2 of the cold storage device 310 based on T0 and Tb, combined with the specific heat capacity, mass and preset change time of the cold storage medium of the cold storage device 310.

[0046] In this embodiment, the current temperature T0 of the cold storage medium is subtracted from the cold storage calculation target temperature Tb, then multiplied by the specific heat capacity and mass of the cold storage medium, then divided by the preset change time, and then multiplied by an adjustment coefficient. The result is the cooling capacity requirement Q2 of the cold storage device 310. The value of the adjustment coefficient is related to the value of the cold storage calculation target temperature Tb. Since the smaller Tb is, the relatively more difficult the cold storage process of the cold storage device is, and the smaller the value of the cold storage calculation target temperature Tb is, the larger the value of the adjustment coefficient is. For example, when the value of Tb is T1, the value of the adjustment coefficient can be 1.1; when the value of Tb is T2 which is smaller than T1, the value of the adjustment coefficient can be 1.3. The preset change time is also the time for the cold storage medium to change from the current temperature T0 to Tb, and this change time is calculated by the refrigerant circulation system. For example, it can be calculated according to the temperature difference between the current temperature T0 of the cold storage medium and the cold storage calculation target temperature Tb, etc. For example, the length of the change time is proportional to the temperature difference.

[0047] In some embodiments, the high-efficiency energy range of the first compressor 105 is (Qx1, Qx2), and the high-efficiency energy range of the second compressor 106 is (Qy1, Qy2). The single-compressor working mode includes the first compressor working mode and the second compressor working mode. The multi-compressor working mode includes the mode where the first compressor and the second compressor work together. In the mode where the first compressor and the second compressor work together, the inlets of the first compressor 105 and the second compressor 106 are connected, and the refrigerant output by the indoor unit 2 and the refrigerant output after heat exchange with the cold storage device 310 are combined and then sent to the inlets of the first compressor 105 and the second compressor 106.

[0048] Step b1 includes: when Qx1 < Qtotal < Qx2, adjusting the working mode of the compressor unit to the first compressor working mode. Figure 3 Schematically shows the refrigerant circulation system in the first compressor working mode, and the arrows on the pipelines therein schematically show the refrigerant flow direction of the refrigerant circulation system in the first compressor working mode. When Qy1 < Qtotal < Qy2, adjusting the working mode of the compressor unit to the second compressor working mode. Figure 4 Schematically shows the refrigerant circulation system in the second compressor working mode, and the arrows on the pipelines therein schematically show the refrigerant flow direction of the refrigerant circulation system in the second compressor working mode. When (Qx1 + Qy1) < Qtotal < (Qx2 + Qy2), adjusting the working mode of the compressor unit to the mode where the first compressor and the second compressor work together. Figure 5 Schematically shows the refrigerant circulation system in the mode where the first compressor and the second compressor work together, and the arrows on the pipelines therein schematically show the refrigerant flow direction of the refrigerant circulation system in the mode where the first compressor and the second compressor work together.

[0049] In this embodiment, by setting the working modes of the first compressor, the second compressor, and the combined working mode of the first and second compressors, and selecting the appropriate working mode when the total heat load Q_total is in different high-efficiency intervals, the compressor unit can operate as efficiently as possible, and the refrigerant circulation system can operate in an energy-saving state.

[0050] In some embodiments, the multi-compressor working mode further includes an independent working mode of the first compressor and the second compressor. In the independent working mode of the first compressor and the second compressor, the inlets of the first compressor 105 and the second compressor 106 are not connected. The refrigerant output by the indoor unit 2 and the refrigerant output after heat exchange with the cold storage device 310 do not converge, and are separately and independently fed into the inlets of the first compressor 105 and the second compressor 106. Step b1 includes: when none of the three inequalities Qx1 < Q_total < Qx2, Qy1 < Q_total < Qy2, and (Qx1 + Qy1) < Q_total < (Qx2 + Qy2) hold, the working mode of the compressor unit is adjusted to the independent working mode of the first compressor and the second compressor. Figure 2 Schematically shows the refrigerant circulation system in the independent working mode of the first compressor and the second compressor, where the arrows on the pipeline indicate the refrigerant flow direction in the independent working mode of the first compressor and the second compressor.

[0051] In this embodiment, when Q_total is not within the high-efficiency intervals of the first compressor and the second compressor 106, and is also not within the high-efficiency interval of the combined operation of the first and second compressors, the independent working mode of the first compressor and the second compressor can be adopted. At this time, the inlets of the first compressor 105 and the second compressor 106 are separately and independently connected to the indoor unit and the cold storage device. Therefore, the refrigerant flowing out of the indoor unit and the cold storage device flows back to different compressors, so that the evaporation temperature of the refrigerant in the indoor unit and the evaporation temperature of the refrigerant in the cold storage device can be different, and the refrigeration effect of the indoor unit on the indoor environment and the cold storage effect of the cold storage device will not affect and restrict each other, enabling the refrigerant circulation system to take into account both the refrigeration effect and the cold storage effect. During the low electricity consumption period, the cold storage device can be used for cold storage while cooling, and the stored cold energy is released during the high electricity consumption period, achieving the purpose of transferring the electricity consumption during the low electricity consumption period to the high electricity consumption period, thus effectively saving the electricity cost and also helping to relieve the electricity consumption pressure during the peak period.

[0052] In some embodiments, a refrigerant circulation system is also disclosed. The refrigerant circulation system applies any of the control methods for refrigeration and cold storage at the same time, such as Figures 1 to 5As shown, the refrigerant circulation system includes: a condenser 108, a compressor unit, an indoor unit 2 located between the condenser 108 and the compressor unit, and a cold storage device 310. The cold storage device 310 is used to absorb and store the cold energy of the refrigerant passing through it. The compressor unit includes a first compressor 105 and a second compressor 106. The compressor unit has two operating modes: a single-unit operating mode with one compressor and a multi-unit operating mode with multiple compressors.

[0053] In some embodiments, the multi-unit operating mode includes a first compressor and a second compressor operating mode. In the first compressor and the second compressor operating mode, the inlets of the first compressor 105 and the second compressor 106 are connected. The refrigerant output from the indoor unit 2 and the refrigerant output after heat exchange with the cold storage device 310 are combined and then sent to the inlets of the first compressor 105 and the second compressor 106.

[0054] This embodiment sets up a working mode where the first compressor and the second compressor work together. When Q is in different high-efficiency ranges, the appropriate working mode is selected, which can make the compressor unit work in a high-efficiency state as much as possible, and the refrigerant circulation system is in a high-efficiency and energy-saving working state.

[0055] In some embodiments, the multi-unit operating mode includes an independent operating mode for the first compressor and the second compressor. In the independent operating mode of the first compressor and the second compressor, the inlets of the first compressor 105 and the second compressor 106 are not connected, and the refrigerant output by the indoor unit 2 and the refrigerant output after heat exchange with the cold storage device 310 do not merge, but are independently fed into the inlet of the first compressor 105 and the inlet of the second compressor 106 respectively.

[0056] Generally, in a cold storage device, the evaporation temperature of the refrigerant needs to be lower than the temperature of the cold storage medium inside the device to store the cold energy. Taking water as the cold storage medium as an example, as the amount of cold energy stored increases, the temperature of the water drops below 0°C, at which point the liquid water transforms into ice. To store more cold energy, the evaporation temperature of the refrigerant entering the cold storage device needs to be below 0°C. However, for the terminal cooling of the indoor unit, the required evaporation temperature is typically around 10°C, meaning the required evaporation temperature of the refrigerant for the indoor unit is higher than that required by the cold storage device.

[0057] This embodiment allows the refrigerant flowing from the cold storage device and the refrigerant flowing from the indoor unit to enter different compressors, ensuring that the cold storage device and the indoor unit have independent evaporation temperatures. This allows the cooling temperature and the cold storage temperature to be adjusted independently, and the cold storage temperature is not limited by the cooling temperature. Therefore, the cold storage temperature can be lower, and the cold storage device can store more cold energy.

[0058] In some embodiments, the air conditioning unit includes the refrigerant circulation system described above.

[0059] like Figures 1 to 5 In the illustrated embodiment, the compressor unit includes a first compressor 105 and a second compressor 106. The outlets of the first compressor 105 and the second compressor 106 are interconnected. The inlet of the second compressor 106 is connected to the inlet of the first compressor 105 via a suction control valve 110. The first compressor 105 and the second compressor 106 are connected in parallel between a gas-liquid separator 104 and a four-way valve 107. The outlets of the first compressor 105 and the second compressor 106 are connected to the first port 107a of the four-way valve. The inlet of the condenser 108 is connected to the second port 107b of the four-way valve. The third port 107c of the four-way valve is connected to the inlet of the gas-liquid separator 104. The outlet of the gas-liquid separator is simultaneously connected to the inlet of the first compressor and the suction control valve 110. The fourth port 107d of the four-way valve is connected to the first gas pipe 302 via an outdoor unit gas pipe 102. The inlet of the second compressor is also connected to the third gas pipe 312 via a second compressor suction pipe 103. The outlet of the condenser 108 is connected to the first liquid pipe 301 via an outdoor control valve 109. The first liquid pipe 301 is connected to the inlet of the indoor unit and the inlet of the cold storage device. A first control valve 305 is installed on the pipe between the first liquid pipe 301 and the inlet of the indoor unit. A sixth control valve 311 is installed on the pipe between the first liquid pipe 301 and the inlet of the cold storage device. A heat storage exchanger control valve 306 is installed on the pipe between the sixth control valve 311 and the inlet 3102 of the cold storage device. The pipes between the first control valve 305 and the inlet of the indoor unit and between the sixth control valve 311 and the heat storage exchanger control valve 306 are connected via a fourth control valve 308. The outlet 3101 of the cold storage device is connected to the fourth port 107d of a four-way valve via a fifth control valve 309. The outlet 3101 of the cold storage device is also connected to the third gas pipe 312 via a seventh control valve 313, and the outlet 3101 of the cold storage device is also connected to the first liquid pipe 301 via a third control valve 307. The inlet of indoor unit 2 is connected to the first control valve 305 via the indoor unit liquid pipe main 201 and the second liquid pipe 303. The outlet of indoor unit 2 is connected to the fifth control valve 309 and the fourth port 107d of the four-way valve via the second gas pipe 304. The refrigerant circulation system is also equipped with a second compressor evaporator temperature sensor 112 to detect the refrigerant temperature at the inlet of the second compressor.

[0060] The actions of valves in different flow paths during simultaneous refrigeration and cold storage are shown in the table below:

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention 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 the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A control method for simultaneous refrigeration and cold storage in a refrigerant circulation system, characterized in that, The refrigerant circulation system includes a condenser (108), a compressor unit, an indoor unit (2) located between the condenser (108) and the compressor unit, and a cold storage device (310). The cold storage device (310) is used to absorb and store the cold energy of the refrigerant passing through it. The compressor unit includes a first compressor (105) and a second compressor (106). The operating modes of the compressor unit include a single-unit operating mode with one compressor and a multi-unit operating mode with multiple compressors. The control method for simultaneous refrigeration and cold storage includes: Step a, in response to the user's temperature setting, obtain the target evaporation temperature T1 of the indoor unit (2) and the target cold storage temperature T2 of the cold storage device (310); Step b, adjusting the compressor unit to bring the evaporation temperature of the indoor unit (2) to T1 and the temperature of the cold storage medium in the cold storage device (310) to T2, includes: Step b1: Obtain the current temperature T0 of the cold storage medium and calculate the difference t between T0 and T1; determine the target evaporation temperature Ta of the indoor unit (2) and the target cold storage temperature Tb of the cold storage device (310) based on t; determine the cooling capacity requirement Q1 of the indoor unit (2) based on Ta, and determine the cooling capacity requirement Q2 of the cold storage device (310) based on T0 and Tb; calculate the sum Q1 and Q2 Qtotal, and adjust the working state of the compressor unit based on whether Qtotal falls within the high energy efficiency range of the single-unit working mode of the compressor unit and whether it falls within the high energy efficiency range of the multi-unit working mode; Step b2: Determine whether T0 has reached T2. If not, repeat step b1.

2. The control method for simultaneous refrigeration and cold storage in a refrigerant circulation system as described in claim 1, characterized in that, Step b1 includes: when t is greater than the first threshold t1, the cooling target evaporation temperature T1 is used as the cooling calculation target evaporation temperature Ta of the indoor unit (2) and the cold storage calculation target temperature Tb of the cold storage device (310).

3. The control method for simultaneous refrigeration and cold storage in a refrigerant circulation system as described in claim 1, characterized in that, Step b1 includes: when t is less than the first threshold t1 and T0 is greater than T2, the target cold storage temperature T2 is used as the cold storage calculation target temperature Tb of the cold storage device (310), and T3 is used as the cooling calculation target evaporation temperature Ta of the indoor unit (2). T3 is calculated by the following formula: T3=T1-k(T1-T2), where k is the adjustment coefficient, and k is greater than 0 and less than 1.

4. The control method for simultaneous refrigeration and cold storage in a refrigerant circulation system as described in claim 3, characterized in that, Step b1 further includes: when the current temperature T0 of the cold storage medium reaches T2, the connection between the cold storage device (310) and the condenser (108) and the compressor unit is closed, and the target evaporation temperature T1 is used as the target evaporation temperature Ta for the indoor unit (2).

5. The control method for simultaneous refrigeration and cold storage in a refrigerant circulation system as described in claim 1, characterized in that, Step b1 includes: determining the cooling capacity requirement Q2 of the cold storage device (310) based on T0 and Tb, combined with the specific heat capacity, mass and preset change time of the cold storage medium of the cold storage device (310).

6. The control method for simultaneous refrigeration and cold storage in a refrigerant circulation system as described in claim 1, characterized in that, The high-efficiency range of the first compressor (105) is (Qx1, Qx2), and the high-efficiency range of the second compressor (106) is (Qy1, Qy2). The single-compressor working mode includes the first-compressor working mode and the second-compressor working mode, and the multi-compressor working mode includes the co-working mode of the first compressor and the second compressor. In the co-working mode of the first compressor and the second compressor, the inlets of the first compressor (105) and the second compressor (106) are connected. The refrigerant output by the indoor unit (2) and the refrigerant output after heat exchange with the cold storage device (310) are combined and then fed into the inlets of the first compressor (105) and the second compressor (106). Step b1 includes: when Qx1 < Qtotal < Qx2, adjusting the working mode of the compressor unit to the first-compressor working mode; when Qy1 < Qtotal < Qy2, adjusting the working mode of the compressor unit to the second-compressor working mode; when (Qx1 + Qy1) < Qtotal < (Qx2 + Qy2), adjusting the working mode of the compressor unit to the co-working mode of the first compressor and the second compressor.

7. The control method for simultaneous refrigeration and cold storage in a refrigerant circulation system as described in claim 6, characterized in that, The multi-compressor working mode further includes the independent working mode of the first compressor and the second compressor. In the independent working mode of the first compressor and the second compressor, the inlets of the first compressor (105) and the second compressor (106) are not connected. The refrigerant output by the indoor unit (2) and the refrigerant output after heat exchange with the cold storage device (310) are not combined and are independently fed into the inlet of the first compressor (105) and the inlet of the second compressor (106) respectively. Step b1 includes: when none of the three inequalities Qx1 < Qtotal < Qx2, Qy1 < Qtotal < Qy2, and (Qx1 + Qy1) < Qtotal < (Qx2 + Qy2) holds, adjusting the working mode of the compressor unit to the independent working mode of the first compressor and the second compressor.

8. A refrigerant circulation system, characterized in that, Applying the control method for simultaneous refrigeration and cold storage as described in any one of claims 1-7, including: a condenser (108), a compressor unit, an indoor unit (2) and a cold storage device (310) provided between the condenser (108) and the compressor unit. The cold storage device (310) is used to absorb and store the cold quantity of the refrigerant passing through it; the compressor unit includes a first compressor (105) and a second compressor (106), and the working mode of the compressor unit includes a single-compressor working mode with one compressor working and a multi-compressor working mode with multiple compressors working.

9. The refrigerant circulation system as described in claim 8, characterized in that, The multi-compressor working mode includes the co-working mode of the first compressor and the second compressor. In the co-working mode of the first compressor and the second compressor, the inlets of the first compressor (105) and the second compressor (106) are connected. The refrigerant output by the indoor unit (2) and the refrigerant output after heat exchange with the cold storage device (310) are combined and then fed into the inlets of the first compressor (105) and the second compressor (106).

10. The refrigerant circulation system as described in claim 8, characterized in that, The multi-unit operating mode includes an independent operating mode for the first compressor and the second compressor. In the independent operating mode of the first compressor and the second compressor, the inlets of the first compressor (105) and the second compressor (106) are not connected. The refrigerant output by the indoor unit (2) and the refrigerant output after heat exchange with the cold storage device (310) do not merge. They are separately sent to the inlet of the first compressor (105) and the inlet of the second compressor (106).

11. An air conditioning unit, characterized in that, Includes the refrigerant circulation system according to any one of claims 8-10.

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