An indirect evaporative air conditioner and its control method

Abstract

Embodiments of the present application disclose an indirect evaporative air conditioner and its control method. The indirect evaporative air conditioner includes: a housing, on which an air inlet and an air outlet for outdoor air are provided; a heat exchange core body, disposed inside the housing and located between the air inlet and the air outlet, and the heat exchange core body is used for heat exchange treatment of indoor air and outdoor air flowing through the heat exchange core body; an indoor fan, used for guiding the indoor air; an outdoor fan, used for guiding the outdoor air, the outdoor fan is at least divided into two groups, and different groups of the outdoor fans operate simultaneously or alternately; an electronic control device, used for controlling the operation of the indoor fan and the outdoor fan. By grouping the outdoor fans in the embodiments of the present application, the outdoor fans in the indirect evaporative air conditioner can operate simultaneously or alternately, which can effectively prevent the use performance of the indirect evaporative air conditioner from being affected due to the abnormality of the heat exchange core body.

Description

Technical Field

[0001] This application relates to the technical field of air conditioners, and more particularly, to an indirect evaporative air conditioner and its control method. Background Art

[0002] The indirect evaporative air conditioning system for data centers mainly consists of a DX system, a heat exchange system, and a spray system, and its operating modes are divided into three types: dry mode, wet mode, and a hybrid mode of wet mode + mechanical refrigeration (or other supplementary cooling methods, such as using a chilled water coil for supplementary cooling). When the outdoor ambient temperature is low, the dry mode is operated; when the outdoor environment is mild, the wet mode is operated; and when the outdoor dry bulb temperature is high and the wet bulb temperature is also high, the hybrid mode is operated.

[0003] In the existing technical solutions, when the application environment temperature is low, although most areas of the heat exchange devices in the heat exchange system are above the dew point, the inner wall temperature of the heat exchange devices is lower than the dew point, which will generate condensate. The condensate accumulates at the bottom of the heat exchange core due to gravity, and the condensate at the bottom is prone to icing during the heat exchange process. Once the condensate freezes, it will cause the heat exchange core to crack. If not dealt with in time, it will affect the use of the heat exchange devices, thereby causing the indirect evaporator to malfunction. Summary of the Invention

[0004] To solve the above technical problems, embodiments of the present application provide an indirect evaporative air conditioner and its control method. By grouping the outdoor fans and adopting an alternating operation mode of different groups of outdoor fans, it can effectively prevent the use performance of the indirect evaporative air conditioner from being affected due to abnormal heat exchange cores.

[0005] Other features and advantages of the present application will become apparent through the following detailed description, or be partially learned through the practice of the present application.

[0006] According to one aspect of the embodiments of the present application, an indirect evaporative air conditioner is provided, including: a housing, on which an air inlet and an air outlet for outdoor air are provided; a heat exchange core, disposed within the housing and located between the air inlet and the air outlet, the heat exchange core being used for heat exchange processing of indoor air and outdoor air flowing through the heat exchange core; an indoor fan, used for guiding the indoor air; an outdoor fan, used for guiding the outdoor air, the outdoor fan being at least divided into two groups, and different groups of the outdoor fans operate simultaneously or alternately; and an electronic control device, used for controlling the operation of the indoor fan and the outdoor fan.

[0007] In some embodiments of the present application, based on the foregoing solution, the indirect evaporative air conditioner has a normal operation mode and an alternating operation mode; wherein, the normal operation mode is a mode in which the outdoor fans operate simultaneously, and the alternating operation mode is a mode in which the outdoor fans operate alternately in groups. If the inlet air temperature of the outdoor air is less than or equal to a preset temperature threshold, the indirect evaporative air conditioner is in the alternating operation mode; if the inlet air temperature of the outdoor air is greater than the preset temperature threshold, the indirect evaporative air conditioner is in the normal operation mode.

[0008] In some embodiments of the present application, based on the foregoing solution, the air inlet is located on one side of the bottom of the heat exchange core, and the outdoor air enters the heat exchange core through the air inlet.

[0009] In some embodiments of the present application, based on the foregoing solution, a flow guiding device is provided on one side of the housing close to the air outlet, and the flow guiding device is used to guide the outdoor air discharged from the air outlet back to the air inlet.

[0010] In some embodiments of the present application, based on the foregoing solution, the flow guiding device includes a cover body covering above the air outlet and flow guiding louvers provided on the cover body. Among them, the flow guiding louvers are located on the side of the cover body close to the air inlet, and the angle of the flow guiding louvers is adjustable.

[0011] In some embodiments of the present application, based on the foregoing solution, the flow guiding device includes a connecting pipe covering above the air outlet, and a full-area flow guiding air duct is connected to the top of the connecting pipe. The full-area flow guiding air duct includes two fan-shaped side plates, and a first connecting plate and a second connecting plate connected to the two fan-shaped side plates. The opening of the full-area flow guiding air duct faces the air inlet, and the full-area flow guiding air duct is used to discharge the outdoor air to the air inlet via the connecting pipe.

[0012] In some embodiments of the present application, based on the foregoing solution, the flow guiding device includes a connecting pipe covering above the air outlet, and a partial-area flow guiding air duct is connected to the top of the connecting pipe. The partial-area flow guiding air duct includes two fan-shaped side plates, and a third connecting plate and a fourth connecting plate connected to the two fan-shaped side plates. Among them, the two fan-shaped side plates divide the top of the connecting plate into at least two regions. The opening of the partial-area flow guiding air duct faces the air inlet, and the partial-area flow guiding air duct is used to partially discharge the outdoor air to the air inlet via the connecting pipe.

[0013] In some embodiments of the present application, based on the foregoing solution, the indirect evaporative air conditioner further includes a spraying system, and the spraying system is located above the heat exchange core. The spraying system is used to cool down the return air temperature of the indoor air.

[0014] According to one aspect of the embodiments of the present application, there is also provided a control method for an indirect evaporative air conditioner, which is used to control the indirect evaporative air conditioner. The control method includes: if the inlet air temperature of the outdoor air is lower than a preset temperature threshold, switching the operating mode to an alternating operating mode; if the inlet air temperature of the outdoor air is higher than or equal to the preset temperature threshold, switching the operating mode to a normal operating mode; wherein, the alternating operating mode is a mode in which the outdoor fans operate alternately in groups, and the normal operating mode is a mode in which the outdoor fans operate simultaneously.

[0015] In some embodiments of the present application, based on the foregoing solution, if the inlet air temperature of the outdoor air is lower than the preset temperature threshold and the operating mode is switched to the alternating operating mode, it includes: obtaining a preset time threshold; operating one or more groups of outdoor fans among multiple groups of outdoor fans, and monitoring whether the operating time of the outdoor fans reaches the time threshold; when the operating time reaches the time threshold, turning off the currently operating outdoor fans and starting another one or more groups of outdoor fans among the multiple groups of outdoor fans.

[0016] In the above technical solution, by setting the outdoor fans in multiple groups and having different groups of outdoor fans operate alternately, it is avoided that under the condition of extremely cold outdoor temperature in winter, condensed water is generated on the inner surface of the heat exchange core during the heat exchange process between the outdoor cold air and the indoor heat return air, thereby improving the stability of the heat exchange core in the indirect evaporative air conditioner to a certain extent.

[0017] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings herein are incorporated into the specification and constitute a part of the specification, showing embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts. In the drawings:

[0019] Figure 1 is a schematic structural diagram of an indirect evaporative air conditioner in the prior art;

[0020] Figure 2 is a schematic diagram of heat exchange at the heat exchange core of an indirect evaporative air conditioner in the prior art;

[0021] Figure 3 is a schematic structural diagram of the indirect evaporative air conditioner prepared by the present application;

[0022] Figure 4 Schematic diagram of heat exchange between outdoor air and indoor air in the indirect evaporation air conditioner prepared for this application;

[0023] Figure 5 Schematic diagram of the structure of the flow guiding device above the air outlet in this application;

[0024] Figure 6 Another schematic diagram of the structure of the flow guiding device above the air outlet in this application;

[0025] Figure 7 Another schematic diagram of the structure of the flow guiding device above the air outlet in this application;

[0026] Figure 8 Another schematic diagram of the structure of the flow guiding device above the air outlet in this application

[0027] Figure 9 Another schematic diagram of the structure of the flow guiding device above the air outlet in this application;

[0028] Figure 10 Schematic diagram of the flow of the control method of the indirect evaporation air conditioner in this application;

[0029] Figure 11 Schematic diagram of the flow of the unit control operation logic in this application. Detailed implementation mode

[0030] Next, the technical solutions in the embodiments of this application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of this application.

[0031] The flowcharts shown in the accompanying drawings are only illustrative, and do not necessarily include all the contents and operations / steps, nor do they necessarily need to be executed in the described order. For example, some operations / steps can be decomposed, while some operations / steps can be combined or partially combined. Therefore, the actual execution order may change according to the actual situation. In addition, it should be noted that: "a plurality of" mentioned in this application means two or more.

[0032] It should be noted in advance that the indirect evaporative air conditioner is an air conditioning unit used to provide air circulation, air filtration, cooling, supplementary mechanical refrigeration, and humidity control for the computer room. Among them, the outdoor air for the outer circulation is in direct contact with water, and the dry-bulb temperature of the outdoor air in the outer circulation is reduced through heat and moisture exchange. The indoor air for the inner circulation exchanges heat with the outdoor air in the outer circulation at the heat exchange device, so that the indoor air in the inner circulation is cooled by the outdoor air in the outer circulation. The outdoor air in the outer circulation undergoes isenthalpic cooling, and the indoor air in the inner circulation undergoes isohumid cooling.

[0033] The indirect evaporative air conditioner mainly consists of a DX system (Direct Expansion system, direct expansion system), a heat exchange system, and a spray system. Among them, the DX system is a cold air system in which the indoor refrigeration finned tube cooler of the indirect evaporative air conditioner directly exchanges heat between air and a freon evaporator; the core device of the heat exchange system is the heat exchange device, and generally, a heat exchange chip can be used as the heat exchange device to achieve heat exchange. The indoor air in the inner circulation and the outdoor air in the outer circulation can exchange temperatures through the heat exchange device. During winter operation, since the inlet air temperature of the outdoor air in the outer circulation is lower than the return air temperature of the indoor air in the inner circulation, the return air of the indoor air in the inner circulation obtains cold energy from the outdoor air in the outer circulation through the heat exchange device, so that the return air temperature of the indoor air in the inner circulation is reduced, and the effect of natural cooling is obtained.

[0034] Furthermore, please refer to Figure 1 , Figure 1 which is a schematic structural diagram of an indirect evaporative air conditioner in the prior art. As shown in the figure, the indirect evaporative air conditioner includes a housing, an indoor fan, a compressor, a heat exchange chip located inside the housing, and an outdoor fan located outside the housing. The housing is provided with an air inlet and an air outlet for outdoor air. The heat exchange chip is arranged between the air inlet and the air outlet for outdoor air. The indoor fan is used to guide the indoor air, and the outdoor fan is used to guide the outdoor air, so that the outdoor air can exchange heat through the heat exchange chip. Furthermore, a spray system is also arranged between the heat exchange chip and the outdoor fan. The spray system includes a condensation device, a recovery device, and a spray device.

[0035] Regarding the structure of the existing indirect evaporative air conditioner, combined with Figure 2 the schematic diagram of heat exchange at the heat exchange core of the indirect evaporative air conditioner in the prior art shown, the three working modes of the indirect evaporative air conditioner can be understood as follows:

[0036] Dry mode: When the dry-bulb temperature of the outdoor air in winter is low enough, both the indoor fan and the outdoor fan are turned on, and the airflows of the indoor air and the outdoor air can exchange heat through the heat exchange core, so as to reduce the high return air temperature of the indoor air in the inner circulation to the required computer room supply air temperature range;

[0037] Wet mode: When the dry-bulb temperature of the outdoor air in the transition season is not low enough, the spray system is turned on, and the wet-bulb temperature of the outdoor air is used to reduce the high return-air temperature of the indoor air undergoing internal circulation to within the required computer room supply-air temperature range.

[0038] Wet mode + DX mode: When the outdoor ambient temperature in summer is too high, the high return-air temperature of the indoor air undergoing internal circulation is reduced to within the required computer room supply-air temperature range through the spray system and the supplementary cooling of the compressor.

[0039] According to the requirements of the existing GB50174-2017 Data Center Design Specification, the supply-air temperature of the indoor air undergoing internal circulation in the data center computer room needs to be controlled within 18 - 26 °C, and the dew-point temperature needs to be controlled within 5.5 - 15 °C. In winter in the northern region, it is extremely cold, and the outdoor temperature is often below 0 °C, and in some areas, the outdoor temperature can even reach below -25 °C. In winter, the indirect evaporative air conditioner can solve the technical problem of computer room heat dissipation by operating in the dry mode and using heat exchange devices. When the temperature of the outdoor air undergoing external circulation is low in winter, the outdoor fan operates at the lowest safe frequency, and most of the area of the heat exchange core is above the dew point, but the temperature of the inner surface wall of the heat exchange core is lower than the dew point, which will cause the generation of condensate. The generated condensate accumulates at the bottom of the heat exchange core under the influence of gravity. If the condensate at the bottom of the heat exchange core continues to be cooled by the outdoor air, icing will occur, and the icing will cause the heat exchange core to crack. In the case of untimely treatment, the circulation channel of the heat exchange chip will be blocked, ultimately affecting the use of the indirect evaporative air conditioner.

[0040] From the above analysis, it can be seen that the indirect evaporative air conditioner can make full use of the outdoor air to cool the return-air temperature of the indoor air undergoing internal circulation when the outdoor temperature is low. However, when the outdoor air is extremely low, the significant defect brought by the icing risk must be considered. Therefore, it is necessary to solve the potential threat of condensate icing to the use of the indirect evaporative air conditioner.

[0041] This application provides an indirect evaporative air conditioner, as Figure 3As shown, the indirect evaporative air conditioner includes a housing 10, a heat exchange core 20, an indoor fan 30, an outdoor fan 40, and an electric control device 50. Among them, an air inlet 110 and an air outlet 120 for outdoor air are provided on the housing 10. The heat exchange core 20 is disposed inside the housing 10 and is located between the air inlet 110 and the air outlet 120. The heat exchange core 20 is used to exchange heat between the indoor air and the outdoor air flowing through the heat exchange core 20. The indoor fan 30 is used to guide the indoor air, and the outdoor fan 40 is used to guide the outdoor air. The outdoor fan 40 is at least divided into two groups, and different groups of outdoor fans operate simultaneously or alternately. The electric control device 50 is used to control the operation of the indoor fan 30 and the outdoor fan 40.

[0042] It should be noted that in this application, the positions of the heat exchange core 20, the indoor fan 30, the outdoor fan 40, and the electric control device 50 are not limited. Figure 3 Only one installation method on the housing is shown, which does not mean that the heat exchange core 20, the indoor fan 30, the outdoor fan 40, and the electric control device 50 in this application can only be installed in the manner as Figure 3 shown.

[0043] In this embodiment, by dividing the outdoor fan 40 into multiple groups, for example, Figure 3 as shown, the outdoor fan 40 is divided into a first outdoor fan group 410 and a second outdoor fan group 420. It should be noted that the number of outdoor fans in each group is not limited. Each outdoor fan group can include one outdoor fan or multiple outdoor fans. Under the control of the electric control device 50, the outdoor fan 40 can operate simultaneously or alternately. In this embodiment, when the outdoor temperature is extremely low, by dividing the outdoor fan 40 into two groups, when the first outdoor fan group 410 is operating, the electric control device 50 can keep the second outdoor fan group 420 in a closed state. After the first outdoor fan group 410 has operated for a period of time, the electric control device 50 can switch the first outdoor fan group 410 from the on state to the off state and switch the second outdoor fan group 420 from the off state to the on state, and use the second outdoor fan group 420 to replace the first outdoor fan group 410 to guide the outdoor air. Since the outdoor fan group guiding the outdoor air is different, and different outdoor fan groups are arranged at the air outlet 120 position, therefore, heat exchange between the outdoor air and the indoor air is realized in different regions of the heat exchange core 20 at different time periods, avoiding the generation of condensate on the inner surface of the heat exchange core 20 under the continuous influence of the extremely cold outdoor air and the accumulation of ice at the bottom, which affects the use of the heat exchange core and further affects the use of the indirect evaporative air conditioner.

[0044] In this application, the indirect evaporative air conditioner has a normal operation mode and an alternating operation mode; among them, the normal operation mode is the mode in which the outdoor fans operate simultaneously, and the alternating operation mode is the mode in which the outdoor fans operate alternately in groups; if the inlet temperature of the outdoor air is less than or equal to the preset temperature threshold, the indirect evaporative air conditioner is in the alternating operation mode, and if the inlet temperature of the outdoor air is greater than the preset temperature threshold, the indirect evaporative air conditioner is in the normal operation mode.

[0045] In this embodiment, according to the control of the outdoor fans by the electronic control device, the indirect evaporative air conditioner can be divided into a normal operation mode and an alternating operation mode. Among them, the normal operation mode is the mode in which the outdoor fans operate simultaneously. When the outdoor air exchanges heat with the indoor air, it will not cause the formation of ice-cold condensate at the bottom of the heat exchange core 20, that is, when the dry bulb temperature of the outdoor air is higher than the critical value at which the condensate freezes, the normal operation mode is adopted and all the outdoor fans are turned on; and when the outdoor temperature in winter is extremely low and the inlet temperature of the outdoor air is less than or equal to the preset temperature threshold, the temperature threshold can be regarded as the critical value at which the condensate freezes, then the alternating operation mode needs to be adopted. For a period of time, only some of the outdoor fans are allowed to be turned on to divert the extremely cold outdoor air to the heat exchange core, so that the extremely cold outdoor air exchanges heat with the relatively warm indoor air. There are still some areas of the heat exchange core that are not passed by the extremely cold outdoor air, and only the relatively warm indoor air passes through the areas where the extremely cold outdoor air does not pass. And in the next period of time, only one or several of the remaining unturned-on outdoor fans are allowed to be turned on to divert the extremely cold outdoor air to the heat exchange core for heat exchange, as Figure 4 shown, Figure 4 is a schematic diagram of the heat exchange between the outdoor air and the indoor air in the indirect evaporative air conditioner prepared in this application. It can be clearly seen from Figure 4 that when the alternating operation mode is adopted, the indoor air and the outdoor air exchange heat at different parts of the heat exchange core 20. By performing heat exchange treatment in different areas of the heat exchange core at different time periods, the freezing of the condensate water at the bottom of the heat exchange core can be avoided, and the performance of the heat exchange core can be adversely affected.

[0046] Furthermore, as Figure 3 shown, the air inlet 110 is located on the side of the bottom of the heat exchange core 20, and the outdoor air enters the heat exchange core 20 through the air inlet 110.

[0047] In this embodiment, the outdoor air enters the heat exchange core 20 through the air inlet 110 and exchanges heat with the indoor air at the heat exchange core 20. The low-temperature outdoor air reduces the return air temperature of the indoor air, thereby dissipating heat from the computer room.

[0048] Even further, as Figure 5As shown, a flow guiding device 130 is provided on one side of the outer shell 10 near the air outlet 120. The flow guiding device 130 is used to guide the outdoor air discharged from the air outlet 120 back to the air inlet 110.

[0049] In this embodiment, considering that in winter, due to the low temperature of the outdoor air, during the heat exchange process between the outdoor air and the indoor air, condensed water is likely to be generated on the inner surface of the heat exchange core 20, and the condensed water is prone to freeze during the further heat exchange process with the outdoor air. In this embodiment, the relatively high-temperature outdoor air discharged from one side of the air outlet 120 after heat exchange is mixed with the relatively low-temperature outdoor air near the air inlet 110 to be introduced into the heat exchange core 20, so as to increase the temperature of the outdoor air introduced into the heat exchange core 20, thereby avoiding the generation of ice blocks at the bottom of the heat exchange core 20 during the heat exchange process between the outdoor air and the indoor air.

[0050] Specifically, in an exemplary embodiment, as Figure 6 shown, the flow guiding device 130 includes a cover body 1301 covering above the air outlet 120 and flow guiding louvers 1302 provided on the cover body 1301. Among them, the flow guiding louvers 1302 are located on the side of the cover body 1301 close to the air inlet 110, and the angle of the flow guiding louvers 1302 is adjustable.

[0051] In this embodiment, as Figure 6 shown, the flow guiding device 130 includes a cover body 1301 and flow guiding louvers 1302 provided on the cover body 1301. The shape of the cover body 1301 can be a cube, a cylinder, a sphere, or other shapes. The specific shape of the cover body 1301 is not limited here. Among them, the flow guiding louvers 1302 and the air inlet 110 are on the same side. By adjusting the angle of the flow guiding louvers 1302, the relatively high-temperature outdoor air discharged from the air outlet 120 can be guided to the vicinity of the air inlet 110 through the flow guiding louvers and mixed with the relatively low-temperature outdoor air, so as to increase the temperature of the outdoor air for heat exchange with the indoor air, thereby reducing the amount of condensed water generated on the inner surface of the heat exchange core 20 to a certain extent and protecting the heat exchange core 20.

[0052] Furthermore, in an exemplary embodiment, as Figure 7 and Figure 8 shown, the flow guiding device 130 includes a connecting pipe 1303 covering above the air outlet 120. The top of the connecting pipe 1303 is connected with a full-area flow guiding air duct 1304. The full-area flow guiding air duct 1304 includes two fan-shaped side plates, and a first connecting plate and a second connecting plate connected to the two fan-shaped side plates. The opening of the full-area flow guiding air duct 1304 faces the air inlet, and the full-area flow guiding air duct 1304 is used to discharge the outdoor air to the air inlet 110 via the connecting pipe 1303.

[0053] In this embodiment, as Figure 7 shown, the flow guiding device 130 is composed of a connecting pipe 1303 and a full-area flow guiding air duct 1304 arranged at the pipe orifice of the connecting pipe 1303. The full-area flow guiding air duct 1304 includes two fan-shaped side plates, and a first connecting plate and a second connecting plate connected to the two fan-shaped side plates. Among them, the first connecting plate is arc-shaped and is connected to the arc edges of the two fan-shaped side plates. The second connecting plate is respectively connected to the first connecting plate and the two fan-shaped side plates, and forms an opening facing the air inlet 110. The relatively high-temperature outdoor air after heat exchange discharged from the air outlet 120 is led out along the connecting plate to the vicinity of the air inlet 110, and is mixed with the relatively low-temperature outdoor air that has not yet undergone heat exchange. Through the co-mixing, the temperature of the outdoor air entering the heat exchange core 20 can be increased, thereby reducing the amount of condensed water generated on the inner surface of the heat exchange core 20 to a certain extent, and protecting the heat exchange core 20. It should be noted that, in this embodiment, as Figure 8 shown, the fan-shaped side plates in the full-area flow guiding air duct 1304 can be replaced with other shapes, and this application is not limited to the method shown in Figure 7 or Figure 8 shown.

[0054] Furthermore, in another exemplary embodiment, as Figure 9 shown, the flow guiding device 130 includes a connecting pipe 1305 covering the upper part of the air outlet 120. The top of the connecting pipe 1305 is connected with a partial-area flow guiding air duct 1306. The partial-area flow guiding air duct 1306 includes two fan-shaped side plates, and a third connecting plate and a fourth connecting plate connected to the two fan-shaped side plates. Among them, the two fan-shaped side plates divide the top of the connecting pipe 1305 into at least two regions. The opening of the partial-area flow guiding air duct 1306 faces the air inlet 110, and the partial-area flow guiding air duct 1306 is used to partially discharge the outdoor air to the air inlet 110 through the connecting pipe 1305.

[0055] Specifically, in this embodiment, the flow guiding device 130 is composed of a connecting pipe 1305 and a partial-area flow guiding air duct 1306 arranged at the pipe orifice of the connecting pipe 1305. The partial-area flow guiding air duct 1306 includes two fan-shaped side plates, and a third connecting plate and a fourth connecting plate connected to the two fan-shaped side plates. Among them, the two fan-shaped side plates can be located at any position of the pipe orifice of the connecting pipe 1305, as Figure 9As shown in the figure, a sector side plate is located at the edge of the connecting pipe 1305, and another sector side plate is located at the middle position of the connecting pipe 1305, thus dividing the pipe orifice area of the connecting pipe 1305 into two parts. Part of the relatively warm outdoor air after heat exchange discharged from the air outlet 120 can be led out along the third connecting plate and the fourth connecting plate to the vicinity of the air inlet 110, and mixed with the relatively cold outdoor air that has not undergone heat exchange. Another part of the relatively warm outdoor air after heat exchange discharged from the air outlet 120 can be directly discharged to the outside along the connecting pipe 1305. Through the mixing, the temperature of the outdoor air entering the heat exchange core 20 can be increased, and to a certain extent, the amount of condensed water generated on the inner surface of the heat exchange core 20 can be reduced, thereby protecting the heat exchange core 20.

[0056] In an exemplary embodiment, as Figure 3 shown, the indirect evaporation air conditioner further includes a spraying system 60. The spraying system 60 is located above the heat exchange core 20, and the spraying system 20 is used to cool down the return air temperature of the indoor air.

[0057] In this embodiment, considering that in summer when the outdoor temperature is relatively high, it is necessary to cool down the temperature of the outdoor air. The spraying system 60 can cool down the relatively high outdoor air, so as to meet the requirement of heat exchange between the indoor air and the outdoor air.

[0058] Furthermore, in the present application, a control method for an indirect evaporation air conditioner is also proposed. The control method includes:

[0059] If the incoming air temperature of the outdoor air is lower than a preset temperature threshold, switch the operation mode to the alternating operation mode;

[0060] If the incoming air temperature of the outdoor air is higher than or equal to the preset temperature threshold, switch the operation mode to the normal operation mode;

[0061] Among them, the alternating operation mode is a mode in which the outdoor fans operate alternately in groups, and the normal operation mode is a mode in which the outdoor fans operate simultaneously.

[0062] In this embodiment, the operation mode of the indirect evaporation air conditioner is adjusted according to the high or low incoming air temperature of the outdoor air. When the incoming air temperature of the outdoor air is relatively low in winter, the indirect evaporation air conditioner adopts the alternating operation mode, and the outdoor fans operate alternately in groups. When the incoming air temperature of the outdoor air is relatively high in other seasons, the normal operation mode is adopted, and all the outdoor fans are started. It should be noted that the temperature threshold here is the incoming air temperature of the outdoor air when all the outdoor fans are started, which can cause condensed water to be generated on the inner surface of the heat exchange core and the condensed water is likely to freeze at the bottom of the heat exchange core.

[0063] Based on the foregoing solution, asFigure 10 As shown, if the inlet air temperature of outdoor air is lower than a preset temperature threshold, the operation mode is switched to an alternating operation mode, including:

[0064] S10. Obtain a preset time threshold;

[0065] S20. Operate one or more of a plurality of outdoor fans and monitor whether the operation time of the outdoor fans reaches the time threshold;

[0066] S30. When the operation time reaches the time threshold, turn off the currently operating outdoor fans and start another one or more of the plurality of outdoor fans.

[0067] In this embodiment, as Figure 11 shown, it is assumed that when the inlet air temperature of outdoor air is -5°C, outdoor air is likely to form condensate on the inner surface of the heat exchange core during the heat exchange process with indoor air, and the formed condensate flows to the bottom of the heat exchange core under the action of gravity and is prone to freezing and expansion, which affects the performance of the heat exchange core. Therefore, when the inlet air temperature of outdoor air is lower than -5°C, the indirect evaporative air conditioner adopts an alternating operation mode, and the first outdoor fan group and the second outdoor fan group operate alternately. When the first outdoor fan group is in the on state, monitor the operation time of the first outdoor fan group. When the operation time of the first outdoor fan group reaches the preset 30 minutes, switch the state of the first outdoor fan group from on to off, and turn on the second outdoor fan group to replace the first outdoor fan group to work. After the operation time of the second outdoor fan group reaches 30 minutes, switch the state of the second outdoor fan group from on to off, so that only part of the outdoor fans are in the on state during the same period. Among them, the time threshold can be regarded as the critical time when condensate appears on the inner surface of the heat exchange core and the condensate is prone to freezing at the bottom of the heat exchange core.

[0068] The above content is only a preferred exemplary embodiment of the present application and is not used to limit the implementation of the present application. Those of ordinary skill in the art can easily make corresponding changes or modifications according to the main concept and spirit of the present application. Therefore, the protection scope of the present application should be subject to the protection scope required by the claims.

Claims

1. An indirect evaporative air conditioner, characterized in that, Comprising: A housing, on which an air inlet for outdoor air and an air outlet are provided; A heat exchange core, arranged inside the housing and located between the air inlet and the air outlet, and the heat exchange core is used for heat exchange treatment of indoor air and outdoor air flowing through the heat exchange core; An indoor fan, used for guiding the indoor air; An outdoor fan, used for guiding the outdoor air, the outdoor fan is at least divided into two groups, and different groups of the outdoor fans operate simultaneously or alternately; when the outdoor fans operate alternately, the indoor air and the outdoor air exchange heat at different parts of the heat exchange core; An electric control device, used for controlling the operation of the indoor fan and the outdoor fan.

2. The indirect evaporative air conditioner according to claim 1, wherein The indirect evaporation air conditioner has a conventional operation mode and an alternate operation mode; wherein, the conventional operation mode is the mode in which the outdoor fans operate simultaneously, and the alternate operation mode is the mode in which the outdoor fans operate alternately according to groups; if the inlet air temperature of the outdoor air is less than or equal to a preset temperature threshold, the indirect evaporation air conditioner is in the alternate operation mode, and if the inlet air temperature of the outdoor air is greater than the preset temperature threshold, the indirect evaporation air conditioner is in the conventional operation mode.

3. The indirect evaporative air conditioner according to claim 1, wherein The air inlet is located on the side of the bottom of the heat exchange core, and the outdoor air enters the heat exchange core through the air inlet.

4. The indirect evaporative air conditioner according to claim 1, wherein A flow guiding device is arranged on one side of the housing close to the air outlet, and the flow guiding device is used for guiding the outdoor air discharged from the air outlet back to the air inlet.

5. The indirect evaporative air conditioner according to claim 4, characterized in that, The flow guiding device includes a cover body covering above the air outlet and flow guiding louvers arranged on the cover body, wherein the flow guiding louvers are located on the side of the cover body close to the air inlet, and the angle of the flow guiding louvers is adjustable.

6. The indirect evaporative air conditioner according to claim 4, characterized in that, The flow guiding device includes a connecting pipe covering above the air outlet, the top of the connecting pipe is connected with a full-area flow guiding air duct, the full-area flow guiding air duct includes two fan-shaped side plates, and a first connecting plate and a second connecting plate connected to the two fan-shaped side plates. The opening of the full-area flow guiding air duct faces the air inlet, and the full-area flow guiding air duct is used for discharging the outdoor air to the air inlet through the connecting pipe.

7. The indirect evaporative air conditioner according to claim 4, characterized in that, The flow guiding device includes a connecting pipe covering above the air outlet, the top of the connecting pipe is connected with a partial-area flow guiding air duct, the partial-area flow guiding air duct includes two fan-shaped side plates, and a third connecting plate and a fourth connecting plate connected to the two fan-shaped side plates. Wherein, the two fan-shaped side plates divide the top of the connecting pipe into at least two areas, the opening of the partial-area flow guiding air duct faces the air inlet, and the partial-area flow guiding air duct is used for discharging part of the outdoor air to the air inlet through the connecting pipe.

8. The indirect evaporative air conditioner according to claim 1, characterized in that, The indirect evaporation air conditioner further includes a spraying system, the spraying system is located above the heat exchange core, and the spraying system is used for cooling the return air temperature of the indoor air.

9. A control method for an indirect evaporation air conditioner, characterized in that, For controlling the indirect evaporation air conditioner according to any one of claims 1-8, the control method includes: If the incoming air temperature of the outdoor air is lower than the preset temperature threshold, switch the operation mode to the alternating operation mode; If the incoming air temperature of the outdoor air is higher than or equal to the preset temperature threshold, switch the operation mode to the normal operation mode; Among them, the alternating operation mode is the mode in which the outdoor fans operate alternately in groups, and the normal operation mode is the mode in which the outdoor fans operate simultaneously.

10. The control method according to claim 9, characterized in that, If the incoming air temperature of the outdoor air is lower than the preset temperature threshold, switching the operation mode to the alternating operation mode includes: Obtain the preset time threshold; Operate one or more groups of outdoor fans among multiple groups of outdoor fans, and monitor whether the operation time of the outdoor fans reaches the time threshold; When the operation time reaches the time threshold, turn off the currently operating outdoor fans, and start another one or more groups of outdoor fans among the multiple groups of outdoor fans.

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