Air conditioning unit and control method thereof

Abstract

The application discloses an air conditioning unit and a control method thereof. The air conditioning unit comprises a fresh air channel, two-stage surface coolers and a return air structure. The fresh air channel is provided with a supply fan. The two-stage surface coolers are a first-stage surface cooler and a second-stage surface cooler arranged in the fresh air channel in sequence along the supply air direction. The liquid inlet of the first-stage surface cooler and the liquid inlet of the second-stage surface cooler are connected to a liquid supply main pipe. The liquid outlet of the first-stage surface cooler is switchably connected to the liquid inlet of the second-stage surface cooler or a liquid return main pipe. The liquid outlet of the second-stage surface cooler is connected to the liquid return main pipe. The return air structure comprises a first-stage return air structure for introducing indoor return air to the air inlet side of the first-stage surface cooler. The application can change the operation state of the surface cooler and the return air state of the return air structure according to different use requirements of users, utilize the fresh air and the return air at the same time, accurately control the indoor humidity, prevent over-drying and significantly improve the indoor comfort.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of air conditioning units, and in particular to an air conditioning unit capable of preventing excessive dehumidification and a control method thereof. BACKGROUND

[0002] According to the data disclosed in the China Building Energy Consumption Report, the whole-process energy consumption of buildings in China accounted for 44.9% of the total energy consumption in 2020, of which the building operation energy consumption accounted for 21.2%. Among the building operation energy consumption, the energy consumption of air conditioning systems is particularly prominent, accounting for more than 60%, and this proportion is showing a continuous upward trend.

[0003] In the research and application of air conditioning system energy saving, the medium-temperature water energy saving system has attracted much attention because it can significantly improve the efficiency of the main unit. Specifically, by increasing the inlet water temperature of chilled water, such as from the commonly used 11℃ to a higher temperature (for example, increasing by 4℃), the outlet temperature of the main unit can be increased accordingly (for example, increasing by 3.5℃), thereby achieving an approximately 12% improvement in the energy efficiency of the main unit. However, this improvement measure also brings new problems: increasing the supply water temperature of chilled water will significantly reduce the dehumidification capacity of commercial terminal units, affecting the user's experience.

[0004] Traditional air conditioning units usually lack the function of independently controlling indoor humidity. When the user turns on the air conditioning dehumidification mode in the room, long-time operation will often cause excessive dehumidification due to the refrigeration process, making the user feel dry throat and uncomfortable. Compared with an indoor environment with higher humidity at the same temperature, the user will feel less comfortable after a period of time at the same temperature. In order to alleviate this discomfort, the user often needs to manually adjust the air conditioning temperature or turn off the air conditioning to warm up, especially at night when sleeping, after turning on the air conditioning in the morning, it is often found that the indoor dehumidification is excessive, which seriously affects the comfort of the human body. These problems are all caused by excessive dehumidification of the air conditioning system, which not only leads to changes in the body temperature, but also causes discomfort to the user. In order to deal with the situation of excessive dehumidification, the existing technology often needs to introduce an additional humidification system, which not only increases the complexity and cost of the unit, but also does not meet the energy saving requirements.

[0005] Therefore, how to design an air conditioning unit with simple structure and capable of flexibly matching different use requirements and a control method thereof is a technical problem to be solved in the industry. SUMMARY

[0006] In order to solve the defects of single function and easy over-drying of the existing air conditioning unit, the air conditioning unit and the control method thereof are provided, the air conditioning unit is designed with two-stage cooling coil and return air structure, the running state of the cooling coil and the return air state of the return air structure can be changed according to different use requirements of the user, the fresh air and the return air are used at the same time, the effect of accurately controlling the indoor humidity and preventing over-drying is realized, and the indoor comfort is significantly improved.

[0007] The technical scheme adopted by the air conditioning unit is as follows: the air conditioning unit comprises a fresh air channel, two-stage cooling coils and a return air structure, the fresh air channel is provided with a supply fan, the two-stage cooling coils are a first-stage cooling coil and a second-stage cooling coil which are sequentially arranged in the fresh air channel along the air supply direction, the liquid inlet of the first-stage cooling coil and the liquid inlet of the second-stage cooling coil are connected to a liquid supply main pipe, the liquid outlet of the first-stage cooling coil can be connected to the liquid inlet of the second-stage cooling coil or a liquid return main pipe in switching mode, the liquid outlet of the second-stage cooling coil is connected to the liquid return main pipe, and the return air structure comprises a first-stage return air structure for introducing indoor return air to the air inlet side of the first-stage cooling coil.

[0008] Further, the return air structure further comprises a second-stage return air structure for introducing indoor return air to the air inlet side of the second-stage cooling coil.

[0009] Further, the first-stage return air structure comprises a first-stage return air port and a first-stage return air fan, and the first-stage return air port is located at the air inlet side of the first-stage cooling coil; the second-stage return air structure comprises a second-stage return air port and a second-stage return air fan, and the second-stage return air port is located between the air outlet side of the first-stage cooling coil and the air inlet side of the second-stage cooling coil.

[0010] Further, the liquid inlet of the first-stage cooling coil and the liquid inlet of the second-stage cooling coil are connected to the liquid supply main pipe through control valves, and the control valves are used for adjusting the liquid supply amount of the first-stage cooling coil and the second-stage cooling coil.

[0011] Further, the air conditioning unit can operate at least one of a rapid dehumidification state, a refrigeration and non-dehumidification state and a refrigeration and humidification state.

[0012] In the rapid dehumidification state, the supply fan is turned off, the air inlet side of the first-stage cooling coil introduces indoor return air, and the liquid outlet of the first-stage cooling coil is connected to the liquid return main pipe.

[0013] In the refrigeration and non-dehumidification state, the supply fan is turned on, the air inlet side of the first-stage cooling coil does not introduce indoor return air, and the liquid outlet of the first-stage cooling coil is connected to the liquid inlet of the second-stage cooling coil.

[0014] In the refrigeration and humidification state, the supply fan is turned on, the air inlet side of the first-stage cooling coil introduces indoor return air, and the liquid outlet of the first-stage cooling coil is connected to the liquid inlet of the second-stage cooling coil.

[0015] Further, the first surface cooler and the second surface cooler are supplied with the same amount of liquid in the fast dehumidifying state; the first surface cooler is supplied with a larger amount of liquid than the second surface cooler in the refrigerating and non-dehumidifying state and the refrigerating and humidifying state.

[0016] Further, the air inlet side of the second surface cooler introduces indoor return air in the fast dehumidifying state, the refrigerating and non-dehumidifying state, and the refrigerating and humidifying state.

[0017] The application further provides a control method of the air conditioning unit, which is applied to the air conditioning unit and comprises the following steps:

[0018] detecting an actual humidity of the indoor environment and analyzing the actual humidity and a humidity set by a user .

[0019] selecting an operation state of the air conditioning unit according to a size of the humidity deviation.

[0020] Further, the step of selecting the operation state of the air conditioning unit according to the analysis result comprises:

[0021] when , the air conditioning unit enters the fast dehumidifying state;

[0022] and / or when , the air conditioning unit enters the refrigerating and non-dehumidifying state;

[0023] and / or when , the air conditioning unit enters the refrigerating and humidifying state;

[0024] wherein, α1 and α2 are the humidity set value.

[0025] Further, the control method further comprises:

[0026] when the air conditioning unit enters the fast dehumidifying state, controlling the return air amount of the return air structure according to the humidity deviation ;

[0027] and / or when the air conditioning unit enters the refrigerating and non-dehumidifying state, detecting an actual temperature of the indoor environment and analyzing a temperature deviation ΔT between the actual temperature T1 and a user set temperature T2, and controlling the return air amount of the return air structure according to the size of the temperature deviation ΔT;

[0028] and / or when the air conditioning unit enters the refrigerating and humidifying state, controlling the return air structure to operate at a set medium return air amount.

[0029] Further, the step of controlling the return air amount of the return air structure according to the humidity deviation comprises:

[0030] when​ When the temperature deviation ΔT is greater than 0℃ and less than β1, the return air structure operates at a set low-return-air-amount;

[0031] When the temperature deviation ΔT is greater than β1 and less than β2, the return air structure operates at a set middle-return-air-amount;

[0032] When the temperature deviation ΔT is greater than β2, the return air structure operates at a set high-return-air-amount;

[0033] Wherein, α3 and α4 are set humidity values.

[0034] Further, the control of the return air amount of the return air structure according to the temperature deviation ΔT includes:

[0035] When 0℃ ≤ ΔT < β1, the return air structure operates at a set low-return-air-amount;

[0036] When β1 ≤ ΔT < β2, the return air structure operates at a set middle-return-air-amount;

[0037] When β2 ≤ ΔT, the return air structure operates at a set high-return-air-amount;

[0038] Wherein, ΔT = T1 - T2, β1 and β2 are set temperature values.

[0039] Further, the control of the return air amount of the return air structure according to the temperature deviation ΔT further includes: when ΔT < 0℃, the supply fan and the return air structure are closed.

[0040] Compared with the prior art, the present application has at least one of the following beneficial effects:

[0041] 1. The design of two-stage surface coolers and a primary return air structure can change the operation state of the surface coolers and the return state of the primary return air structure according to different use requirements of users, utilize fresh air and return air at the same time, accurately control indoor humidity, prevent over-drying, and significantly improve indoor comfort;

[0042] 2. The design of a secondary return air structure introduces indoor return air into the air inlet side of the secondary surface cooler, adjusts the temperature of the mixed gas through the secondary return air structure, avoids the temperature of the supply air after secondary cooling being too low, and utilizes indoor return air to supplement fresh air, without the need of additionally designing an exhaust air passage, thereby simplifying the air duct structure;

[0043] 3. The air conditioning unit can be switched to different operation states to perform indoor dehumidification, refrigeration without dehumidification, refrigeration and humidification, etc., especially the recovery of the return water of the primary surface cooler in combination with fresh air and return air for indoor humidification, without the need of additionally increasing a humidifier or the like, thereby realizing one machine with multiple functions;

[0044] ​​4. The air conditioning unit autonomously adjusts the operating state according to the indoor environment parameters, improves the indoor humidity and / or indoor temperature control accuracy, and maintains the indoor environment at a comfortable level, thereby optimizing the user experience. BRIEF DESCRIPTION OF DRAWINGS

[0045] The application will be described in further detail below with reference to the embodiments and drawings, in which:

[0046] Figure 1 is a schematic diagram of the fresh air channel of the preferred embodiment of the application;

[0047] Figure 2 is a schematic diagram of the pipe connection of the two-stage surface cooler of the application;

[0048] Figure 3 is a schematic diagram of the liquid flow when the two-stage surface cooler of the application works independently;

[0049] Figure 4 is a schematic diagram of the liquid flow when the two-stage surface cooler of the application works in communication;

[0050] Figure 5 is a schematic diagram of the air flow in the fresh air channel of the application in the fast dehumidification state;

[0051] Figure 6 is a schematic diagram of the air flow in the fresh air channel of the application in the refrigeration and dehumidification state;

[0052] Figure 7 is a schematic diagram of the air flow in the fresh air channel of the application in the refrigeration and humidification state;

[0053] Figure 8 is a schematic diagram of the control method of the application;

[0054] BRIEF DESCRIPTION OF DRAWINGS: 1, fresh air channel; 11, air inlet; 12, air outlet; 13, primary return air inlet; 14, secondary return air inlet; 2, primary surface cooler; 3, secondary surface cooler; 4, primary return air fan; 5, secondary return air fan; 6, liquid supply main pipe; 7, liquid return main pipe; 8, control valve; 9, on-off valve. DETAILED DESCRIPTION

[0055] In order to make the technical problems, technical solutions and beneficial effects of the application more clear and explicit, the application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the application and do not limit the application.

[0056] As Figure 1As shown, the air conditioning unit provided by the present application comprises: a fresh air channel 1, a first-stage surface cooler 2, a second-stage surface cooler 3, and a return air structure. The air inlet 11 of the fresh air channel 1 is connected to the outside, and the air outlet 12 is connected to the inside. The fresh air channel 1 is provided with a supply fan. When the supply fan is turned on, it drives the outdoor fresh air to flow from the air inlet 11 to the air outlet 12 of the fresh air channel 1. The first-stage surface cooler 2 and the second-stage surface cooler 3 are sequentially arranged in the fresh air channel 1 along the air supply direction. After the outdoor fresh air enters the fresh air channel 1, it first passes through the first-stage surface cooler 2, and then passes through the second-stage surface cooler 3, and then flows to the air outlet 12 of the fresh air channel 1.

[0057] The return air structure is used to introduce indoor return air into the fresh air channel 1. Specifically, the return air structure comprises a first-stage return air structure. The first-stage return air structure can introduce indoor return air into the air inlet side of the first-stage surface cooler 2. Since the first-stage surface cooler 2 is located upstream of the air supply of the second-stage surface cooler 3, the indoor return air supplied to the air inlet side of the first-stage surface cooler 2 will continue to flow to the second-stage surface cooler 3 after passing through the first-stage surface cooler 2.

[0058] As shown in Figures 2 to 4 The liquid inlet of the first-stage surface cooler 2 and the liquid inlet of the second-stage surface cooler 3 are connected to the liquid supply main pipe 6. The liquid outlet of the first-stage surface cooler 2 and the liquid outlet of the second-stage surface cooler 3 are connected to the liquid return main pipe 7. However, the liquid outlet of the first-stage surface cooler 2 can be switched to be connected to the liquid inlet of the second-stage surface cooler 3. That is, the return water of the first-stage surface cooler 2 mixes with the water supplied by the liquid supply main pipe 6 and flows into the second-stage surface cooler 3.

[0059] By designing two-stage surface coolers and a first-stage return air structure, the present application can change the operating state of the surface coolers and the return air state of the first-stage return air structure according to different use requirements of users. The return water of the first-stage surface cooler 2, fresh air, and indoor return air are simultaneously utilized. By increasing the water inlet temperature of the second-stage surface cooler 3 and increasing the gas temperature on the air inlet side of the first-stage surface cooler 2, the temperature and humidity of the airflow after being processed by the two-stage surface coolers are adjusted. The indoor humidity is accurately controlled, and the effect of preventing excessive dehumidification is achieved. The indoor comfort is significantly improved.

[0060] As shown in Figure 1 In the preferred embodiment of the present application, the return air structure further comprises a second-stage return air structure. The second-stage return air structure can introduce indoor return air into the air inlet side of the second-stage surface cooler 3. The indoor return air supplied to the air inlet side of the second-stage surface cooler 3 will not pass through the first-stage surface cooler 2. After passing through the second-stage surface cooler 3, the indoor return air will flow to the air outlet 12 of the fresh air channel 1.

[0061] In more detail, based on the first-stage return air structure and the second-stage return air structure, the working state of the return air structure is divided into three cases:

[0062] The first, the first return air structure is opened, the second return air structure is closed, the indoor return air is introduced into the air inlet side of the first surface cooler 2, and is sequentially sent to the indoor through the first surface cooler 2 and the second surface cooler 3.

[0063] The second, the first return air structure is closed, the second return air structure is opened, the indoor return air is introduced into the air inlet side of the second surface cooler 3, and the indoor return air is sent to the indoor through the second surface cooler 3.

[0064] The third, the first return air structure and the second return air structure are opened, the indoor return air is introduced into the air inlet side of the first surface cooler 2 and the air inlet side of the second surface cooler 3, the return air introduced into the air inlet side of the first surface cooler 2 is sequentially sent to the indoor through the first surface cooler 2 and the second surface cooler 3, and the return air introduced into the air inlet side of the second surface cooler 3 is sent to the indoor through the second surface cooler 3.

[0065] The advantage of this design is that the indoor return air is introduced into the air inlet side of the second surface cooler 3 through the second return air structure, the gas temperature of the air inlet side of the second surface cooler 3 is adjusted by using the indoor return air, the temperature of the secondary cooling air supply is avoided to be too low, and the air volume of the fresh air is supplemented by using the indoor return air, so that the exhaust air channel is not needed to be additionally designed, and the air duct structure is simplified.

[0066] As shown in FIG. 1, Figure 1 In some feasible embodiments of the present application, the first return air structure and the second return air structure are similar in structure, and each return air structure is designed with a corresponding return air port. The return air port of the first return air structure is a first return air port 13, and the return air port of the second return air structure is a second return air port 14.

[0067] Specifically, the first return air port 13 and the second return air port 14 are arranged on the fresh air channel 1, and the second return air port 14 is located between the air outlet side of the first surface cooler 2 and the air inlet side of the second surface cooler 3. The indoor return air enters the fresh air channel 1 through the return air port. In actual application, a baffle can be designed at the return air port, and the baffle is controlled to move to close or open the return air port, which is equivalent to an air valve. By designing the return air port at different positions of the fresh air channel 1, the indoor return air can be accurately and reliably sent to the air inlet side of the corresponding surface cooler. The switching of the opening and closing states of the return air port can flexibly adjust the mixing ratio of the return air and the fresh air, so as to ensure that the air supply temperature and humidity meet the user's use demand, and improve the overall efficiency of the unit.

[0068] Each return air inlet is provided with a return air fan with adjustable air speed, the first return air fan 4 is arranged at the first return air inlet 13, and the first return air fan 4 drives indoor return air to flow into the first return air inlet 13 when working, the second return air fan 5 is arranged at the second return air inlet 14, and the second return air fan 5 drives indoor return air to flow into the second return air inlet 14 when working. The advantage of this design is that the air speed of the return air can be flexibly adjusted according to actual needs to change the amount of return air introduced into the first return air inlet 13 and the second return air inlet 14, so as to maintain the stability of the supply air temperature and humidity, and better adapt to different indoor environments and load changes.

[0069] As shown in Figures 2 to 4 In some feasible embodiments of the present application, the liquid inlet of the first surface cooler 2 and the liquid inlet of the second surface cooler 3 are connected to the liquid supply main pipe 6 through the control valve 8, and the control valve 8 is used to adjust the liquid supply amount of the first surface cooler 2 and the second surface cooler 3.

[0070] Specifically, in order to simplify the connection structure, the control valve 8 can adopt a three-way valve, the first end of the three-way valve is connected to the liquid supply main pipe 6, the second end is connected to the liquid inlet of the first surface cooler 2, and the third end is connected to the liquid inlet of the second surface cooler 3, and when in use, the liquid supply amount of the first surface cooler 2 and the second surface cooler 3 is adjusted by controlling the opening degree of the second end and the third end of the three-way valve.

[0071] In addition, the liquid outlet of the first surface cooler 2 is connected to the liquid inlet of the second surface cooler 3 and the liquid return main pipe 7 through the on-off valve 9, and the on-off valve 9 is used to switch the connection state of the liquid outlet of the first surface cooler 2, when the on-off valve 9 is in the first state, the liquid outlet of the first surface cooler 2 is connected to the liquid return main pipe 7, the two surface coolers are connected in parallel between the liquid supply main pipe 6 and the liquid return main pipe 7, and each works independently; when the on-off valve 9 is in the second state, the liquid outlet of the first surface cooler 2 is connected to the liquid inlet of the second surface cooler 3, and the liquid outlet of the first surface cooler 2 is blocked from the liquid return main pipe 7, the return water of the first surface cooler 2 is mixed with the water supplied by the liquid supply main pipe 6 and flows into the second surface cooler 3, and the water temperature of the second surface cooler 3 is improved.

[0072] This design can ensure that each surface cooler only receives appropriate cooling medium (usually water) when needed to complete different functions and prevent excessive dehumidification.

[0073] Based on the pipeline connection structure of the two-stage surface cooler and the first return air structure, the air conditioning unit can operate at least one of the rapid dehumidification state, the refrigeration and non-dehumidification state, and the refrigeration and humidification state, which will be described in detail below.

[0074] In the fast dehumidification state, the air supply fan is closed, the air inlet side of the primary surface cooler 2 is introduced into the indoor return air (the primary return air structure is opened), and the liquid outlet of the primary surface cooler 2 is connected to the return liquid main 7. The two-stage surface coolers independently carry out refrigeration and dehumidification, and the indoor return air is sent back to the indoor environment after being dehumidified by the primary surface cooler 2 and the secondary surface cooler 3, so that the actual humidity of the indoor environment is rapidly reduced, thereby achieving the effect of fast dehumidification.

[0075] In the refrigeration and non-dehumidification state, the air supply fan is opened, the air inlet side of the primary surface cooler 2 is not introduced into the indoor return air (the primary return air structure is closed), and the liquid outlet of the primary surface cooler 2 is connected to the liquid inlet of the secondary surface cooler 3. The outdoor fresh air with high temperature and high humidity is dehumidified into low-temperature and low-humidity gas by the primary surface cooler 2, and the return water of the primary surface cooler 2 is mixed with the water supply of the water supply main 6 and flows into the secondary surface cooler 3, thereby improving the water inlet temperature of the secondary surface cooler 3, which is higher than the dew point temperature of the mixed gas on the air inlet side of the secondary surface cooler 3. Therefore, the mixed gas only carries out refrigeration but not dehumidification when passing through the secondary surface cooler 3.

[0076] In the refrigeration and non-dehumidification state, the air supply fan is opened, the air inlet side of the primary surface cooler 2 is not introduced into the indoor return air (the primary return air structure is closed), and the liquid outlet of the primary surface cooler 2 is connected to the liquid inlet of the secondary surface cooler 3. The outdoor fresh air with high temperature and high humidity is dehumidified into low-temperature and low-humidity gas by the primary surface cooler 2, and the return water of the primary surface cooler 2 is mixed with the water supply of the water supply main 6 and flows into the secondary surface cooler 3, thereby improving the water inlet temperature of the secondary surface cooler 3, which is higher than the dew point temperature of the mixed gas on the air inlet side of the secondary surface cooler 3. Therefore, the mixed gas only carries out refrigeration but not dehumidification when passing through the secondary surface cooler 3.

[0077] In order to improve the operation effect of the air conditioning unit in different states, in the fast dehumidification state, the liquid supply of the primary surface cooler 2 and the secondary surface cooler 3 is the same, so that both the surface coolers have good dehumidification effect; in the refrigeration and non-dehumidification state and the refrigeration and humidification state, the liquid supply of the primary surface cooler 2 is greater than that of the secondary surface cooler 3, at this time, the cooling medium distributed to the secondary surface cooler 3 is less, and the return water of the primary surface cooler 2 can effectively improve the liquid inlet temperature of the secondary surface cooler 3, thereby weakening the dehumidification capacity of the secondary surface cooler 3.

[0078] As Figure 1As shown, in a preferred embodiment, a two-stage return air structure is designed between the primary surface cooler 2 and the secondary surface cooler 3. This two-stage return air structure introduces indoor return air in the rapid dehumidification state, the cooling without dehumidification state, and the cooling with humidification state. That is, it adds the corresponding working state of the two-stage return air structure in each of the states described above.

[0079] like Figure 5 As shown, in rapid dehumidification mode, the air supply fan is turned off, and indoor return air is introduced into the air inlet side of both the primary surface cooler 2 and the secondary surface cooler 3 (both the primary and secondary return air structures are open). The liquid outlet of the primary surface cooler 2 is connected to the return liquid main pipe 7. The two surface coolers independently perform cooling and dehumidification. The indoor return air is sent back to the room after being dehumidified by the primary surface cooler 2 and the secondary surface cooler 3. The return air volume is larger and the dehumidification effect is faster.

[0080] like Figure 6 As shown, in the cooling but not dehumidifying state, the blower is turned on, the air inlet side of the first-stage surface cooler 2 does not introduce indoor return air, and the air inlet side of the second-stage surface cooler 3 introduces indoor return air (the first-stage return air structure is closed and the second-stage return air structure is open), and the liquid outlet of the first-stage surface cooler 2 is connected to the liquid inlet of the second-stage surface cooler 3. The high-temperature and high-humidity outdoor fresh air is transformed into low-temperature and low-humidity gas through the first-stage surface cooler 2, and then mixed with the indoor return air introduced from the air inlet side of the second-stage surface cooler 3. The indoor return air can flow back into the room through the two-stage return air structure, replenishing the fresh air volume without the need for additional exhaust duct design. The return water from the first-stage surface cooler 2 mixes with the supply water from the liquid supply main pipe 6 and flows into the second-stage surface cooler 3, raising the inlet water temperature of the second-stage surface cooler 3 to exceed the dew point temperature of the mixed gas on the air inlet side of the second-stage surface cooler 3 (although the indoor return air will cause a slight increase in the dry bulb temperature of the mixed gas on the air inlet side of the second-stage surface cooler 3, the increased dry bulb temperature will still be at a low level, and the corresponding dew point temperature will also be low, so the inlet water temperature of the second-stage surface cooler 3 will still be higher than this dew point temperature). Therefore, the mixed gas only cools and does not dehumidify when passing through the second-stage surface cooler 3.

[0081] like Figure 7As shown, in the refrigeration and humidification state, the air supply fan is turned on, the indoor return air is introduced into the air inlet side of the first and second surface coolers 2 and 3 (the first and second return air structures are opened), and the liquid outlet of the first surface cooler 2 is connected to the liquid inlet of the second surface cooler 3. The outdoor air with high temperature and high humidity is first mixed with the indoor return air introduced into the air inlet side of the first surface cooler 2 to reduce the dry-bulb temperature of the outdoor air and the dew point temperature of the mixed gas in this section, thereby greatly reducing the dehumidification effect of the first surface cooler 2, so that the mixed gas flowing through the first surface cooler 2 maintains humidity, the low-temperature and high-humidity gas supplied by the first surface cooler 2 is mixed with the indoor return air introduced into the air inlet side of the second surface cooler 3, and the air supply is supplemented by the indoor return air. The return water of the first surface cooler 2 is mixed with the water supplied by the water supply main pipe 6 and flows into the second surface cooler 3, thereby increasing the water inlet temperature of the second surface cooler 3, which is higher than the dew point temperature of the mixed gas at the air inlet side of the second surface cooler 3 (although the indoor return air will cause the dry-bulb temperature of the mixed gas at the air inlet side of the second surface cooler to rise slightly, the dry-bulb temperature after the rise is still at a low level, and the corresponding dew point temperature is also low, so the water inlet temperature of the second surface cooler 3 is still higher than the dew point temperature). Therefore, the mixed gas only performs refrigeration and not dehumidification after passing through the second surface cooler 3, and the refrigeration and humidification effect is achieved under the joint action of the first and second surface coolers 2 and 3.

[0082] For ease of understanding, the following is a table showing the relationship between indoor relative humidity and dry-bulb and dew point temperatures, which provides three numerical examples for illustration:

[0083] Dry-bulb temperature (°C) Wet-bulb temperature (°C) Dew-point temperature (°C) Relative humidity 30 24 21.703 61.08％ 27 18 12.82 41.37％ 24 14 5.09 31.64％

[0084] When the air conditioning unit is running, the dry-bulb and dew point temperatures will decrease under the action of the air conditioner, and the relative humidity of the gas will be smaller. For example, in a common application scenario, the supply and return water temperature of the air conditioning unit in the refrigeration mode is set to 6 / 11°C, the water supply temperature of the first surface cooler is lower than the dew point temperature of the outdoor air with high temperature and high humidity, the low-temperature air flowing out of the first surface cooler is mixed with the indoor return air, and the temperature of the gas is still at a low level, and the corresponding dew point temperature is also low. The water supply of the first surface cooler is greater than that of the second surface cooler, and the return water of the first surface cooler flowing into the second surface cooler will increase the water inlet temperature of the second surface cooler, so that the temperature of the second surface cooler is higher than the dew point temperature of the mixed gas, thereby ensuring that the mixed gas only performs refrigeration and not dehumidification after passing through the second surface cooler.

[0085] As shown in Figure 8 , the present application also provides a control method of the air conditioning unit, which is applied to the air conditioning unit described above, and includes the following steps:

[0086] detecting the actual humidity of the indoor environment and analyzing the actual humidity and the humidity deviation of the humidity set by the user ​

[0087] According to the size of the humidity deviation , the operating state of the air conditioning unit is selected.

[0088] The advantage of this design is that by monitoring the humidity of the indoor environment, a more reasonable operating state of the air conditioning unit can be selected to ensure that the indoor humidity remains within the user's set range, avoiding discomfort caused by excessive humidity or low humidity.

[0089] Specifically, selecting the operating state of the air conditioning unit according to the analysis result includes:

[0090] When , it means that the indoor humidity is too high, at this time the air conditioning unit enters the rapid dehumidification state, effectively reducing the indoor humidity, avoiding the discomfort caused by excessive humidity;

[0091] When , it means that the indoor humidity is within an acceptable range, at this time the air conditioning unit enters the refrigeration and dehumidification state, maintaining the suitability of indoor temperature and humidity;

[0092] When , it means that the indoor humidity is too low, the air conditioning unit enters the refrigeration and humidification state, increasing humidity while cooling to ensure that the indoor environment is cool and not too dry, improving indoor comfort;

[0093] Wherein, α1 and α2 are set humidity values.

[0094] The advantage of this design is that it can accurately control the operating state of the air conditioning unit under different humidity conditions, avoiding unnecessary dehumidification or humidification operation, improving the energy efficiency of the air conditioning system, and maintaining the stability of the indoor humidity.

[0095] In the preferred embodiment of the present application, the control method further comprises:

[0096] When the air conditioning unit enters the rapid dehumidification state, the return air volume of the return air structure is controlled according to the humidity deviation , the return air volume is more accurately adjusted by the humidity deviation , by increasing the return air volume, the circulation of indoor humid air can be accelerated, the dehumidification efficiency can be improved, and by reducing the return air volume, the load of the air conditioning unit can be reduced, thereby reducing energy consumption.

[0097] And / or when the air conditioning unit enters the refrigeration and dehumidification state, the first return air structure is closed, the second return air structure is opened, the actual temperature of the indoor environment is detected, and the temperature deviation ΔT of the actual temperature T1 and the user set temperature T2 is analyzed, the return air amount of the return air structure is controlled according to the size of the temperature deviation ΔT, and accurate control of the return air amount helps to realize rapid adjustment and stable control of the temperature, and can also avoid energy waste caused by excessive refrigeration or insufficient refrigeration.

[0098] And / or when the air conditioning unit enters the refrigeration and humidification state, the return air structure is controlled to run at the set medium return air amount, and the medium return air amount helps to balance the change of indoor humidity, which can meet the refrigeration demand and maintain the suitability of indoor humidity.

[0099] This design realizes intelligent control of the air conditioning unit, can dynamically adjust the return air amount according to different operating states and indoor environmental parameters, and helps to improve the operating efficiency of the air conditioning system and user experience.

[0100] Specifically, according to the humidity deviation The return air amount of the return air structure includes:

[0101] When the humidity deviation is small, the return air structure runs at the set low return air amount to avoid excessive dehumidification. When the humidity deviation is moderate, the return air structure runs at the set medium return air amount to avoid large fluctuations in indoor humidity.

[0102] When the humidity deviation is large, the return air structure runs at the set high return air amount to rapidly reduce indoor humidity.

[0103] When the humidity deviation is large, the return air structure runs at the set high return air amount to rapidly reduce indoor humidity. Wherein, α3 and α4 are set humidity values.

[0104] This design improves the accuracy of humidity control by dynamically adjusting the return air amount, provides a more comfortable indoor environment for users, and at the same time can reduce unnecessary energy consumption and improve the operating energy efficiency of the air conditioning unit.

[0105] Specifically, according to the size of the temperature deviation ΔT, the return air amount of the return air structure includes:

[0106] When 0℃≤ΔT<β1, the temperature deviation is small, the return air structure runs at the set low return air amount, and the return air structure runs at the set low return air amount to avoid excessive refrigeration.

[0107] When β1≤ΔT<β2, the temperature deviation is moderate, the return air structure runs at the set medium return air amount, and the return air structure runs at the set medium return air amount to avoid large fluctuations in indoor temperature.

[0108] When β1≤ΔT<β2, the temperature deviation is moderate, the return air structure runs at the set medium return air amount, and the return air structure runs at the set medium return air amount to avoid large fluctuations in indoor temperature.

[0109] ​When β2≤ΔT, it indicates that the temperature deviation is large, the return air structure operates at the set high return air volume, and the indoor temperature can be rapidly reduced;

[0110] Wherein, ΔT=T1-T2, β1 and β2 are set temperature values.

[0111] This design improves the accuracy of temperature control by dynamically adjusting the return air volume, provides a more comfortable indoor environment for users, and reduces unnecessary energy consumption and improves the operating energy efficiency of the air conditioning unit.

[0112] In addition, as an optimization, when ΔT<0℃, it indicates that the indoor temperature is lower than the user set temperature, the supply air fan and the return air structure are turned off, and the two-stage cooling coil stops water supply. This design can avoid the indoor temperature being too low due to excessive refrigeration, and can reduce the energy consumption of the air conditioning unit and improve the user experience.

[0113] It should be noted that the α1, α2, α3 and α4 are relative humidity, T1, T2, β1 and β2 are dry-bulb temperature, and the indoor temperature and humidity can be detected every certain period of time (e.g., 20 minutes), i.e., after the air conditioning unit enters the current operating state and operates for a period of time, the indoor temperature and humidity are detected again. In actual application, the detection interval time and the temperature and humidity set values can be set according to personal preferences or use requirements, and the indoor temperature and humidity environment can be more flexibly customized.

[0114] For ease of understanding, an application example of the present application is used for illustration,

[0115] After the air conditioning unit enters the refrigeration mode, the supply and return water temperature of the air conditioning unit is set to 6 / 11℃, the supply air fan operates at the set high air volume, α1 is -3%, α2 is 3%, α3 is 10%, α4 is 20%, β1 is 3℃, β2 is 7℃, the primary return air fan and the secondary return air fan are each provided with three air volumes, i.e., high air volume, medium air volume and low air volume.

[0116] If the air conditioning unit enters the rapid dehumidification state, the two-stage cooling coil supplies water at a ratio of 1:1, when the primary return air fan and the secondary return air fan are both opened at the high air volume, when the primary return air fan and the secondary return air fan are both opened at the medium air volume, and when the primary return air fan and the secondary return air fan are both opened at the low air volume.

[0117] If When ΔT > 7℃, the secondary return air fan is started at high air speed; when 7℃ > ΔT > 3℃, the secondary return air fan is started at medium air speed; when 0℃ ≤ ΔT < 3℃, the secondary return air fan is started at low air speed; and when ΔT < 0℃, the supply air fan and the return air structure are turned off, and the two-stage cooling coil stops supplying water.

[0118] If When ΔT > 7℃, the secondary return air fan is started at high air speed; when 7℃ > ΔT > 3℃, the secondary return air fan is started at medium air speed; when 0℃ ≤ ΔT < 3℃, the secondary return air fan is started at low air speed; and when ΔT < 0℃, the supply air fan and the return air structure are turned off, and the two-stage cooling coil stops supplying water.

[0119] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. The order of execution or completion of the operations of the devices and methods shown and described herein need not be limited to the order presented in this specification unless a particular order is clearly indicated. Additionally, the terms "exemplary" and "example" are used herein to mean "serving as an example, instance, or illustration," and should not necessarily be construed as preferred or advantageous over other examples.

[0120] Techniques, methods, and apparatus known to those of ordinary skill in the relevant art can not be discussed in detail herein. However, the techniques, methods, and apparatus should be considered part of the described technology unless specifically stated otherwise. In all examples shown and discussed herein, any specific values should be interpreted as merely illustrative and not limiting. Thus, other examples of the exemplary embodiments can have different values. It should be noted that like reference numerals and letters refer to like items in the following drawings, and thus, once an item is defined in one drawing, it need not be discussed further in subsequent drawings.

[0121] The specific embodiments described herein have been shown by way of example in the accompanying drawings and detailed description. It should be understood by those skilled in the art that various alternate and / or equivalent implementations can be substituted for those specifically shown and described without departing from the scope of the present disclosure. This disclosure is intended to cover any and all alternatives, modifications, equivalents, and / or improvements to the specific embodiments described.

Claims

1. A control method of an air conditioning unit, the air conditioning unit comprising: a fresh air channel, wherein a fresh air fan is installed; two-stage surface coolers, wherein a first-stage surface cooler and a second-stage surface cooler are sequentially arranged in the fresh air channel along a fresh air direction, a liquid inlet of the first-stage surface cooler and a liquid inlet of the second-stage surface cooler are connected to a liquid supply main, a liquid outlet of the first-stage surface cooler is switchably connected to the liquid inlet of the second-stage surface cooler or a liquid return main, and a liquid outlet of the second-stage surface cooler is connected to the liquid return main; and a return air structure, wherein a first-stage return air structure is configured to introduce indoor return air to an air inlet side of the first-stage surface cooler; the control method is characterized in that: the air conditioning unit is capable of operating in at least one of a rapid dehumidification state, a refrigeration and non-dehumidification state, and a refrigeration and humidification state; in the rapid dehumidification state, the fresh air fan is turned off, the air inlet side of the first-stage surface cooler is introduced with indoor return air, and the liquid outlet of the first-stage surface cooler is connected to the liquid return main; in the refrigeration and non-dehumidification state, the fresh air fan is turned on, the air inlet side of the first-stage surface cooler is not introduced with indoor return air, and the liquid outlet of the first-stage surface cooler is connected to the liquid inlet of the second-stage surface cooler; and in the refrigeration and humidification state, the fresh air fan is turned on, the air inlet side of the first-stage surface cooler is introduced with indoor return air, and the liquid outlet of the first-stage surface cooler is connected to the liquid inlet of the second-stage surface cooler. The return air structure further comprises a second-stage return air structure configured to introduce indoor return air to an air inlet side of the second-stage surface cooler. The first-stage return air structure comprises a first-stage return air port and a first-stage return air fan, and the first-stage return air port is located on the air inlet side of the first-stage surface cooler. The second-stage return air structure comprises a second-stage return air port and a second-stage return air fan, and the second-stage return air port is located between the air outlet side of the first-stage surface cooler and the air inlet side of the second-stage surface cooler. The liquid inlet of the first-stage surface cooler and the liquid inlet of the second-stage surface cooler are connected to the liquid supply main through a control valve, and the control valve is configured to adjust the liquid supply amount of the first-stage surface cooler and the second-stage surface cooler. In the rapid dehumidification state, the liquid supply amount of the first-stage surface cooler and the second-stage surface cooler is the same; in the refrigeration and non-dehumidification state and the refrigeration and humidification state, the liquid supply amount of the first-stage surface cooler is greater than that of the second-stage surface cooler. The air inlet side of the second-stage surface cooler is introduced with indoor return air in the rapid dehumidification state, the refrigeration and non-dehumidification state, and the refrigeration and humidification state. The control method further comprises: detecting an actual humidity of an indoor environment and analyzing a humidity deviation Δφ of the actual humidity φ1 and a user-set humidity φ2; and selecting an operating state of the air conditioning unit according to the size of the humidity deviation Δφ. The selection of the operating state of the air conditioning unit according to the analysis result comprises: when Δφ ≥ α2, the air conditioning unit enters the rapid dehumidification state; and / or when α2 > Δφ ≥ α1, the air conditioning unit enters the refrigeration and non-dehumidification state; and / or when Δφ < α1, the air conditioning unit enters the refrigeration and humidification state; wherein Δφ = φ1 - φ2, and α1 and α2 are set humidity values.

2. The control method according to claim 1, characterized by, The control method further comprises:

3. The control method according to claim 2, characterized by, ​ ​ 4. The control method according to claim 1, characterized by, ​ 5. The control method according to claim 1, characterized by, ​ 6. The control method according to claim 1, characterized by ​ 7. The control method according to any one of claims 1 to 6, characterized by, ​ ​ ​ 8. The control method according to claim 7, characterized by ​ ​ ​ ​ ​ 9. The control method according to claim 8, characterized by, ​ When the air conditioning unit enters the rapid dehumidification state, the return air volume of the return air structure is controlled according to the humidity deviation Δφ; When the air conditioning unit enters the refrigeration and dehumidification state, the actual temperature of the indoor environment is detected, the temperature deviation ΔT between the actual temperature T1 and the user set temperature T2 is analyzed, and the return air volume of the return air structure is controlled according to the size of the temperature deviation ΔT; When the air conditioning unit enters the refrigeration and humidification state, the return air structure is controlled to run at a set medium return air volume.

10. The control method according to claim 9, characterized by, The control of the return air volume of the return air structure according to the humidity deviation Δφ comprises: When α3> Δφ ≥ α2, the return air structure runs at a set low return air volume; When α4> Δφ ≥ α3, the return air structure runs at a set medium return air volume; When Δφ ≥ α4, the return air structure runs at a set high return air volume; Wherein, α3 and α4 are set humidity values.

11. The control method according to claim 9, characterized by, The control of the return air volume of the return air structure according to the size of the temperature deviation ΔT comprises: When 0℃ ≤ ΔT < β1, the return air structure runs at a set low return air volume; When β1 ≤ ΔT < β2, the return air structure runs at a set medium return air volume; When β2 ≤ ΔT, the return air structure runs at a set high return air volume; Wherein, ΔT = T1-T2, β1 and β2 are set temperature values.

12. The control method according to claim 11, characterized by, The control of the return air volume of the return air structure according to the size of the temperature deviation ΔT further comprises: when ΔT < 0℃, the supply fan and the return air structure are turned off.

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