Hygrothermal alternating test chamber and control method thereof

Abstract

The present application belongs to the technical field of damp heat alternating test box, especially relates to a damp heat alternating test box and a control method thereof, which comprises a hollow box body, a humidifying assembly and a temperature control assembly, the inner cavity of the box body is provided with a test cavity and a circulating air duct in communication, the temperature control assembly comprises a heater arranged in the circulating air duct and used for increasing the air temperature, a refrigeration evaporator used for reducing the air temperature, and a circulating fan used for driving the air flow to circulate between the test cavity and the circulating air duct, the output end of the humidifying assembly is connected with the inner cavity of the circulating air duct and used for providing damp heat steam, and the damp heat alternating test box further comprises a dehumidifying assembly, the dehumidifying assembly comprises a temperature and humidity controller, a temperature and humidity sensor, a dehumidifying evaporator and a dry air device.

Description

Technical Field

[0001] This invention belongs to the technical field of damp heat alternating test chambers, and particularly relates to a damp heat alternating test chamber and its control method. Background Technology

[0002] In the field of reliability testing, high and low temperature alternating damp heat testing is a core method for evaluating the environmental adaptability of electronic products, automotive parts, and new energy components (such as batteries and PCBs). International advanced standards (such as IEC 60068-2-38 and GB / T2423.4) and stringent corporate specifications (such as Volkswagen PV 1200, BMW AIEF, and Apple AC 69) all require rapid and smooth switching between low and high humidity conditions based on simulated natural temperature and humidity cycles. In existing technologies, temperature control in damp heat alternating test chambers includes: using a heater to increase air temperature and using an evaporator to decrease air temperature. Humidity control in damp heat alternating test chambers includes: using an electric steam boiler to generate high-temperature steam, injecting it into the chamber to increase humidity, and using the surface of an evaporator to cool the air, causing water vapor in the air to condense into dew and be discharged, thus reducing absolute humidity. The evaporator serves as both a cooling and dehumidifying component. This structure has the following shortcomings: (1) There is a vacuum zone when switching between high and low humidity. When the evaporator is used for cooling, it cannot respond quickly and be used for dehumidification. In addition, due to the thermal and humid inertia of the test chamber wall, the inner wall of the circulating air duct and the test sample itself, the water film attached to the surface is difficult to remove instantly, resulting in the actual humidity being much higher than the target value within the set time. (2) The control capability of low humidity conditions is poor. For example, the test standards of car companies such as BMW require that the dew point temperature must follow the humidity change curve quickly and linearly while the temperature is cycling. In order to ensure low humidity conditions, the evaporator needs to continue to work at the same or higher power. At this time, in order to meet the temperature cycle change curve, the heater needs to To offset the excess cooling capacity, and the amount of change offset must remain constant, that is, under low humidity conditions, the operating power of the heater needs to change with the operating power of the evaporator, resulting in excessive energy coupling, which can easily lead to test failure; (3) When faced with drastic changes in alternating damp heat curves, existing control methods often experience overshoot and oscillation due to the lack of prediction of system inertia. When the relative humidity setpoint changes abruptly, the sensor (usually wet bulb or capacitive) senses the change and feeds it back to the actuator (humidification / cooling) with a long lag time, which means that the equipment can only find the deviation in the data after the test is completed, and cannot make effective corrections during operation. Summary of the Invention

[0003] The first objective of this invention is to provide a damp heat alternating test chamber, which aims to solve the technical problems of vacuum zone during high and low humidity switching and poor control capability of low humidity conditions in the prior art.

[0004] To achieve the above objectives, this invention provides a humidity and heat alternating test chamber, comprising a hollow chamber body, a humidification component, and a temperature control component. The inner cavity of the chamber body is provided with a test chamber and a circulating air duct. The temperature control component includes a heater for increasing air temperature, a refrigeration evaporator for decreasing air temperature, and a circulating fan for driving airflow between the test chamber and the circulating air duct, all located within the circulating air duct. The output end of the humidification component is connected to the inner cavity of the circulating air duct to provide humid heat steam. The chamber also includes a dehumidification component, comprising a temperature and humidity controller, a temperature and humidity sensor, a dehumidifying evaporator, and a dry air device. The dehumidifying evaporator is located within the circulating air duct, acts on the water vapor within the circulating air duct, and is electrically connected to the temperature and humidity controller. The output end of the dry air device is connected to the inner cavity of the circulating air duct to provide dry air and is electrically connected to the temperature and humidity controller. The temperature and humidity sensor is located within the test chamber and is electrically connected to the temperature and humidity controller.

[0005] Optionally, the temperature and humidity controller has an input module for inputting the target temperature and humidity.

[0006] Optionally, it also includes a pressure relief valve, which is located on the chamber body and connected to the temperature and humidity control electrical signal. The pressure relief valve can connect or disconnect the test chamber from the outside world.

[0007] Optionally, the circulating fan, the heater, and the refrigeration evaporator are arranged sequentially from top to bottom in the circulating air duct in the vertical direction.

[0008] Optionally, the dehumidifying evaporator is internally connected to the circulating air duct and is located vertically between the heater and the refrigerating evaporator.

[0009] Optionally, it also includes an air supply pipe, the outer end of which is connected to the output end of the dry air device, the inner end of which penetrates the box body and its end is located in the circulating air duct.

[0010] Optionally, the dry air device includes a single unit, a pre-filter, an adsorption dryer, a post-filter, and a solenoid valve arranged sequentially along the gas delivery direction. The solenoid valve is electrically connected to the temperature and humidity controller, and its output end is connected to the outer end of the air supply pipe. The input end of the single unit is connected to an external air source.

[0011] Optionally, it also includes a refrigeration and dehumidification circuit, which includes a compressor, a condenser, and a throttling device. The return port of the dehumidifying evaporator is connected to the input port of the compressor, and the liquid inlet of the dehumidifying evaporator is connected to the output port of the compressor through the throttling device and the condenser.

[0012] The second objective of this invention is to provide a control method that addresses the technical problem in the prior art where a long feedback lag time leads to deviations in the data after the experiment.

[0013] To achieve the above objectives, an embodiment of the present invention provides a control method for a damp heat alternating test chamber, comprising the following steps:

[0014] (S1) Temperature and humidity parameter comparison: The temperature and humidity parameters in the test chamber are collected by the temperature and humidity sensor and compared with the test curve of the preset target temperature and humidity.

[0015] (S2) Select the dehumidification mode. The temperature and humidity controller starts or stops the working element corresponding to the dehumidification mode according to the comparison result. When the humidity of the test chamber is in the high humidity range and the test curve does not require rapid dehumidification, proceed to step (S2-1); when the humidity of the test chamber is in the high humidity range and the test curve requires rapid dehumidification, proceed to step (S2-2); when the humidity of the test chamber is in the high humidity range and needs to be stable in the low humidity range, proceed to step (S2-3).

[0016] (S2-1) High humidity dehumidification mode: The temperature and humidity controller transmits a stop working command to the dry air device and a start working command to the dehumidifying evaporator. Low temperature refrigerant is introduced into the dehumidifying evaporator. The hot and humid steam in the test chamber flows through the surface of the dehumidifying evaporator. The hot and humid steam condenses into liquid water and is discharged from the chamber body.

[0017] (S2-2) Rapid dehumidification mode: The temperature and humidity controller sends a start-up command to the dry air device and to the dehumidifying evaporator. Low-temperature refrigerant is introduced into the dehumidifying evaporator. The hot and humid vapor in the test chamber flows over the surface of the dehumidifying evaporator. The hot and humid vapor condenses into liquid water and is discharged from the chamber body. The dry air device controls the amount of dry air introduced by pulse width modulation or continuous operation until the humidity drops to within the target allowable deviation range.

[0018] (S2-3) Maintain the low humidity dehumidification mode and perform the above steps (S2-1) or (S2-2) until the humidity in the test chamber reaches the low humidity range. The dry air device maintains a slight positive pressure by intermittently introducing dry air.

[0019] Optionally, the high humidity range in step (S2) is 65%RH~98%RH and the low humidity range is 5%RH~20%RH; the dew point of the dry air in step (S2-2) is ≤-40℃.

[0020] The above-mentioned technical solutions in the damp heat alternating test chamber provided in the embodiments of the present invention have at least one of the following technical effects:

[0021] (1) The temperature inside the chamber is controlled by a refrigeration evaporator, and the humidity inside the chamber is controlled by a dehumidifying evaporator. The two independent evaporators work independently, which solves the technical defect of traditional single evaporators that cannot achieve both dehumidification depth and response speed. Dry air is introduced into the chamber through a dry air device. When conducting low humidity tests or rapidly switching from high humidity to low humidity, the low moisture content of the dry air is used to forcibly replace the humid air inside the chamber, which significantly shortens the humidity drop time and avoids the humidity tailing phenomenon. On the other hand, the introduction of dry air not only directly reduces the relative humidity, but also, because its temperature is usually room temperature or slightly lower, assists in breaking the humidity. This invention disrupts the water film balance on the inner wall of the housing and the surface of the air duct, avoiding the trailing phenomenon in traditional solutions where the evaporator continuously frosts but the humidity cannot be reduced. At the same time, the intervention of the dry air device can appropriately reduce the excessively low dew point requirement of the evaporator, thereby reducing the load on the refrigeration system and achieving overall energy efficiency optimization. Through the synergistic effect of the forced replacement effect of dry air and the continuous condensation and dehumidification of the evaporator, this invention achieves rapid switching from high humidity (e.g., 98%RH) to low humidity (e.g., 5%RH), shortening the switching time by more than 50% compared to traditional solutions. Moreover, there is no humidity overshoot or obvious trailing phenomenon during the switching process, ensuring the smooth reproduction of the alternating curve.

[0022] (2) The present invention provides a dehumidifying evaporator specifically for dehumidification. The dehumidifying evaporator is moderately decoupled from the temperature regulation function of refrigeration evaporation, avoiding the energy interference caused by the strong coupling of dehumidification and cooling in the traditional scheme. This ensures that the dehumidification process no longer sacrifices the accuracy of temperature control, while improving the dehumidification depth and system stability.

[0023] (3) Based on the current humidity and the rate of change of humidity, the present invention determines that the system is in three different test stages: high humidity constant humidity, high humidity to low humidity switching, and low humidity constant humidity. Based on this, the invention decides when to activate the three dehumidification modes, thus realizing the composite control of feedforward prediction and feedback correction. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the structure of the damp heat alternating test chamber provided in an embodiment of the present invention.

[0026] Figure 2This is a schematic diagram of the dry air device provided in an embodiment of the present invention.

[0027] The following are the labeling elements in the figure:

[0028] 1—Box body; 11—Test chamber; 12—Circulating air duct

[0029] 2—Temperature control component; 21—Heater; 22—Refrigeration evaporator

[0030] 23—Circulating fan; 3—Dehumidification assembly; 31—Dehumidification evaporator

[0031] 32—Dry air device; 321—Air supply pipe; 322—Single unit

[0032] 323—Pre-filter; 324—Adsorption dryer; 325—Post-filter

[0033] 326—Solenoid valve. Detailed Implementation

[0034] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain embodiments of the present invention, and should not be construed as limiting the present invention.

[0035] In the description of the embodiments of the present invention, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0036] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of the present invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0037] In the embodiments of the present invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention according to the specific circumstances.

[0038] In one embodiment of the present invention, such as Figures 1-2As shown, a damp heat alternating test chamber is provided, including a hollow chamber body 1, a humidification component, and a temperature control component 2. The inner cavity of the chamber body 1 is provided with a test chamber 11 and a circulating air duct 12. The temperature control component 2 includes a heater 21 for increasing air temperature, a refrigeration evaporator 22 for decreasing air temperature, and a circulating fan 23 for driving airflow to circulate between the test chamber 11 and the circulating air duct 12, all located within the circulating air duct 12. The output end of the humidification component is connected to the inner cavity of the circulating air duct 12 to provide damp heat steam. The system includes a dehumidification component 3, which comprises a temperature and humidity controller, a temperature and humidity sensor, a dehumidifying evaporator 31, and a dry air device 32. The dehumidifying evaporator 31 is located within the circulating air duct 12, acts on the water vapor within the circulating air duct 12, and is electrically connected to the temperature and humidity controller. The output end of the dry air device 32 is connected to the inner cavity of the circulating air duct 12 to provide dry air and is electrically connected to the temperature and humidity controller. The temperature and humidity sensor is located within the test chamber 11 and is electrically connected to the temperature and humidity controller. Temperature circulation control within the chamber is achieved using a refrigeration evaporator 22, and humidity circulation control is achieved using a dehumidifying evaporator 31. The two independent evaporators operate independently, overcoming the technical limitation of traditional single evaporators where dehumidification depth and response speed cannot be simultaneously achieved. Dry air is introduced into the chamber body 1 via a dry air device 32. During low-humidity tests or rapid transitions from high to low humidity, the low moisture content of the dry air forces the replacement of the humid air within the chamber, significantly shortening the humidity reduction time and avoiding humidity trailing. Furthermore, the introduction of dry air not only directly reduces relative humidity but also, because its temperature is typically room temperature or slightly lower, assists in breaking down humidity. The invention disrupts the water film balance on the inner wall and duct surface of the main body 1, avoiding the trailing phenomenon in traditional solutions where the evaporator continuously frosts but the humidity fails to decrease. Simultaneously, the intervention of the dry air device 32 appropriately reduces the excessively low dew point requirement of the evaporator, thereby reducing the load on the refrigeration system and optimizing overall energy efficiency. Through the synergistic effect of forced displacement of dry air and continuous condensation and dehumidification by the evaporator, this invention achieves rapid switching from high humidity (e.g., 98% RH) to low humidity (e.g., 5% RH), shortening the switching time by more than 50% compared to traditional solutions. Furthermore, there is no humidity overshoot or significant trailing phenomenon during the switching process, ensuring smooth reproduction of the alternating curve. This invention incorporates a dedicated dehumidifying evaporator 31, which is appropriately decoupled from the temperature regulation function of the refrigeration evaporator. This avoids energy interference caused by the strong coupling of dehumidification and cooling in traditional solutions, ensuring that the dehumidification process does not sacrifice temperature control accuracy, while simultaneously improving dehumidification depth and system stability.In this embodiment, the humidification component is an electric boiler device. The water in the boiler is heated by an electric heating tube to boil, thereby generating hot and humid steam that is introduced into the chamber body 1. The hot and humid steam is introduced into the chamber body 1 through a gas pipe. This device is a standard component of the damp heat alternating test chamber, so its structure will not be described in detail in this embodiment.

[0039] In one embodiment of the present invention, such as Figures 1-2 As shown, the temperature and humidity controller has an input module for inputting the target temperature and humidity. Specifically, the input module is a touch screen display on the temperature and humidity controller, through which the user can input the test curve of the target temperature and humidity.

[0040] In one embodiment of the present invention, such as Figures 1-2 As shown, it also includes a pressure relief valve, which is located on the chamber body 1 and connected to the temperature and humidity control electrical signal. The pressure relief valve can connect or isolate the test chamber 11 from the outside world. Specifically, by using the pressure relief valve port in conjunction with the intermittent introduction of dry air device 32, the air pressure inside the chamber body 1 is maintained at a slightly positive pressure state slightly higher than the ambient atmospheric pressure during the low humidity holding stage. During the low humidity holding stage, solenoid valve 326 introduces dry air in an intermittent pulse manner, maintaining a slightly positive pressure state (slightly higher than the ambient atmospheric pressure) inside the test chamber. This effectively inhibits the reverse seepage of external humid air through gaps such as door seals, cable holes, and observation windows, solving the industry problem of unstable control and easy humidity rebound in conventional equipment in the low humidity range.

[0041] In one embodiment of the present invention, such as Figures 1-2 As shown, the circulating fan 23, the heater 21, and the evaporator 22 are arranged in the circulating air duct 12 in a vertical direction from top to bottom.

[0042] In one embodiment of the present invention, such as Figures 1-2 As shown, the dehumidifying evaporator 31 is internally connected to the circulating air duct 12 and is located vertically between the heater 21 and the refrigeration evaporator 22.

[0043] In one embodiment of the present invention, such as Figures 1-2 As shown, it also includes an air supply pipe 321, the outer end of which is connected to the output end of the dry air device 32, the inner end of which penetrates the box body 1 and its end is located in the circulating air duct 12.

[0044] In one embodiment of the present invention, such as Figures 1-2As shown, the dry air device 32 includes a single-unit assembly 322, a pre-filter 323, an adsorption dryer 324, a post-filter 325, and a solenoid valve 326 arranged sequentially along the gas delivery direction. The solenoid valve 326 is electrically connected to the temperature and humidity controller, and its output terminal is connected to the outer end of the air supply pipe 321. The input terminal of the single-unit assembly 322 is connected to an external air source. Specifically, when the humidity inside the chamber enters the target low humidity range, the solenoid valve 326 is switched to an intermittent on / off mode to maintain a slight positive pressure inside the chamber and compensate for the humidity rise caused by door seal leakage, while preventing excessive introduction of dry air that could cause the humidity to fall below the set lower limit.

[0045] In one embodiment of the present invention, such as Figures 1-2 As shown, it also includes a refrigeration and dehumidification circuit, which includes a compressor, a condenser, and a throttling device. The return port of the dehumidifying evaporator 31 is connected to the input port of the compressor, and the liquid inlet of the dehumidifying evaporator 31 is connected to the output port of the compressor through the throttling device and the condenser. Specifically, in this embodiment, the refrigeration evaporator 22 is independently configured with a refrigeration and cooling circuit with the same function. The two sets of refrigeration circuits in this embodiment are conventional technologies in the art, so they will not be described in detail in this embodiment.

[0046] In one embodiment of the present invention, a control method for a damp heat alternating test chamber is also provided, comprising the following steps:

[0047] (S1) Temperature and humidity parameter comparison: The temperature and humidity parameters in the test chamber 11 are collected by the temperature and humidity sensor and compared with the test curve of the preset target temperature and humidity.

[0048] (S2) Select the dehumidification mode. The temperature and humidity controller starts or stops the working element corresponding to the dehumidification mode according to the comparison result. When the humidity of the test chamber 11 is in the high humidity range and the test curve does not require rapid dehumidification, proceed to step (S2-1). When the humidity of the test chamber 11 is in the high humidity range and the test curve requires rapid dehumidification, proceed to step (S2-2). When the humidity of the test chamber 11 is in the high humidity range and needs to be stable in the low humidity range, proceed to step (S2-3).

[0049] (S2-1) High humidity dehumidification mode: The temperature and humidity controller transmits a stop working command to the dry air device 32 and a start working command to the dehumidifying evaporator 31. Low temperature refrigerant is introduced into the dehumidifying evaporator 31. The hot and humid steam in the test chamber 11 flows through the surface of the dehumidifying evaporator 31. The hot and humid steam condenses into liquid water and is discharged outside the chamber body 1.

[0050] (S2-2) Rapid dehumidification mode: The temperature and humidity controller sends a start-up command to the dry air device 32 and to the dehumidifying evaporator 31. Low-temperature refrigerant is introduced into the dehumidifying evaporator 31. The hot and humid steam in the test chamber 11 flows over the surface of the dehumidifying evaporator 31. The hot and humid steam condenses into liquid water and is discharged outside the chamber body 1. The dry air device 32 controls the amount of dry air introduced by pulse width modulation or continuous operation until the humidity drops to within the target allowable deviation range.

[0051] (S2-3) Maintain the low humidity dehumidification mode and perform the above steps (S2-1) or (S2-2) until the humidity in the test chamber 11 reaches the low humidity range. The dry air device 32 maintains a slight positive pressure by intermittently introducing dry air. This invention determines the system's operating stage based on the current humidity and humidity change rate: high humidity constant humidity, high humidity to low humidity switching, and low humidity constant humidity. Based on this, it decides when to activate the three dehumidification modes, achieving a composite control of feedforward prediction and feedback correction. It can stably execute alternating humidity and heat curves involving switching between 98%RH high humidity and below 5%RH low humidity, with the humidity deviation at the switching point controlled within ±3%RH, meeting the temperature and humidity testing requirements of products from companies such as Volkswagen, BMW, and Apple.

[0052] In one embodiment of the present invention, such as Figures 1-2 As shown, the high humidity range in step (S2) is 65%RH~98%RH, and the low humidity range is 5%RH~20%RH; the dew point of the dry air in step (S2-2) is ≤-40℃.

[0053] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A damp heat alternating test chamber, comprising a hollow chamber body, a humidification component, and a temperature control component, wherein the inner cavity of the chamber body is provided with a communicating test chamber and a circulating air duct, the temperature control component includes a heater for increasing air temperature, a refrigeration evaporator for decreasing air temperature, and a circulating fan for driving airflow to circulate between the test chamber and the circulating air duct, the output end of the humidification component is connected to the inner cavity of the circulating air duct for providing damp heat steam, characterized in that, It also includes a dehumidification component, which includes a temperature and humidity controller, a temperature and humidity sensor, a dehumidifying evaporator, and a dry air device. The dehumidifying evaporator is located in the circulating air duct, acts on the water vapor in the circulating air duct, and is electrically connected to the temperature and humidity controller. The output end of the dry air device is connected to the inner cavity of the circulating air duct to provide dry air and is electrically connected to the temperature and humidity controller. The temperature and humidity sensor is located in the test chamber and is electrically connected to the temperature and humidity controller.

2. The damp heat alternating test chamber according to claim 1, characterized in that, The temperature and humidity controller has an input module for inputting the target temperature and humidity.

3. The damp heat alternating test chamber according to claim 1, characterized in that, It also includes a pressure relief valve, which is located on the chamber body and connected to the temperature and humidity control electrical signal. The pressure relief valve can connect or disconnect the test chamber from the outside world.

4. The damp heat alternating test chamber according to claim 1, characterized in that, The circulating fan, the heater, and the refrigeration evaporator are arranged vertically from top to bottom within the circulating air duct.

5. The damp heat alternating test chamber according to claim 4, characterized in that, The dehumidifying evaporator is internally connected to the circulating air duct and is located vertically between the heater and the refrigerating evaporator.

6. The damp heat alternating test chamber according to claim 1, characterized in that, It also includes an air supply pipe, the outer end of which is connected to the output end of the dry air device, the inner end of which penetrates the box body and its end is located in the circulating air duct.

7. The damp heat alternating test chamber according to claim 6, characterized in that, The dry air device includes a single unit, a pre-filter, an adsorption dryer, a post-filter, and a solenoid valve arranged sequentially along the gas delivery direction. The solenoid valve is electrically connected to the temperature and humidity controller, and its output end is connected to the outer end of the air supply pipe. The input end of the single unit is connected to an external air source.

8. The damp heat alternating test chamber according to claim 1, characterized in that, It also includes a refrigeration and dehumidification circuit, which includes a compressor, a condenser and a throttling device. The return port of the dehumidifying evaporator is connected to the input port of the compressor, and the liquid inlet of the dehumidifying evaporator is connected to the output port of the compressor through the throttling device and the condenser.

9. A control method for a damp heat alternating test chamber according to any one of claims 1 to 8, comprising the following steps: (S1) Temperature and humidity parameter comparison: The temperature and humidity parameters in the test chamber are collected by the temperature and humidity sensor and compared with the test curve of the preset target temperature and humidity. (S2) Select the dehumidification mode. The temperature and humidity controller starts or stops the working element corresponding to the dehumidification mode according to the comparison result. When the humidity of the test chamber is in the high humidity range and the test curve does not require rapid dehumidification, proceed to step (S2-1); when the humidity of the test chamber is in the high humidity range and the test curve requires rapid dehumidification, proceed to step (S2-2); when the humidity of the test chamber is in the high humidity range and needs to be stable in the low humidity range, proceed to step (S2-3). (S2-1) High humidity dehumidification mode: The temperature and humidity controller transmits a stop working command to the dry air device and a start working command to the dehumidifying evaporator. Low temperature refrigerant is introduced into the dehumidifying evaporator. The hot and humid steam in the test chamber flows through the surface of the dehumidifying evaporator. The hot and humid steam condenses into liquid water and is discharged from the chamber body. (S2-2) Rapid dehumidification mode: The temperature and humidity controller sends a start-up command to the dry air device and to the dehumidifying evaporator. Low-temperature refrigerant is introduced into the dehumidifying evaporator. The hot and humid vapor in the test chamber flows over the surface of the dehumidifying evaporator. The hot and humid vapor condenses into liquid water and is discharged from the chamber body. The dry air device controls the amount of dry air introduced by pulse width modulation or continuous operation until the humidity drops to within the target allowable deviation range. (S2-3) Maintain the low humidity dehumidification mode and perform the above steps (S2-1) or (S2-2) until the humidity in the test chamber reaches the low humidity range. The dry air device maintains a slight positive pressure by intermittently introducing dry air.

10. The control method according to claim 9, characterized in that, The high humidity range in step (S2) is 65%RH~98%RH, and the low humidity range is 5%RH~20%RH; the dew point of the dry air in step (S2-2) is ≤-40℃.

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