Fresh air single rotary dehumidification process

Abstract

The application relates to the technical field of dehumidification processes, and discloses a fresh air single-rotor dehumidification process, which is used for mixing fresh air and return air after the fresh air and the return air are introduced into respective channels to be cooled and then sent into a rotor, and comprises the following steps: S1, sequentially arranging a fresh air valve, a fresh air filter, a fresh air medium-temperature surface cooler and a fresh air low-temperature surface cooler along a fresh air direction to form a fresh air channel and introduce fresh air to carry out precooling and cooling dehumidification treatment. The fresh air single-rotor dehumidification process can avoid unnecessary deep cooling of dry return air and reduce the consumption of invalid sensible heat by introducing fresh air and return air into respective independent channels and arranging respective medium-temperature surface coolers and low-temperature surface coolers, so that the fresh air bears all deep dehumidification loads, and the return air only needs to be selectively cooled according to actual needs, and the heat exchange area of the surface cooler on the return air side is selected as 10% to 25% of that on the fresh air side.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of dehumidification process, in particular to a fresh air single-rotor dehumidification process. BACKGROUND

[0002] The existing fresh air single-rotor dehumidifier with return air function is an air treatment device capable of simultaneously processing outdoor fresh air and indoor return air. The core is to deeply adsorb and dehumidify the mixed fresh air and return air by a dehumidification rotor, and some models also support secondary return air design to further save energy. This device can effectively introduce fresh air, control indoor humidity, and also recycle return air energy, so it is suitable for clean laboratories, precision manufacturing, biomedicine and other places with strict humidity requirements.

[0003] However, in actual application, due to the design of the air flow channel that the fresh air and the return air are pre-mixed and then cooled by the surface cooler, a large amount of dry return air is unnecessarily deeply cooled, resulting in a significant increase in the annual refrigeration energy consumption of the water chiller. Moreover, when facing the sudden increase of fresh air humidity load in plum rain season or the temperature fluctuation of return air in autumn and winter, only the coil cooling capacity can be adjusted as a whole, and the dehumidification strength of the fresh air side cannot be independently enhanced. SUMMARY

[0004] (I) Technical problems solved: In view of the deficiencies of the prior art, the present application provides a fresh air single-rotor dehumidification process, which solves the problems of high energy consumption and inability to independently control the dehumidification strength of fresh air caused by pre-mixing and cooling of fresh air and return air in the prior art.

[0005] (II) Technical solutions: To achieve the above purpose, the present application is implemented by the following technical solutions: a fresh air single-rotor dehumidification process for introducing fresh air and return air into respective channels for cooling treatment and then mixing and sending into a rotor, comprising the following steps: S1, sequentially arranging a fresh air damper, a fresh air filter, a fresh air medium-temperature surface cooler and a fresh air low-temperature surface cooler in the fresh air direction to form a fresh air channel and introduce fresh air for pre-cooling and cooling dehumidification treatment; S2, sequentially arranging a return air damper, a return air filter, a return air medium-temperature surface cooler and a return air low-temperature surface cooler in the return air direction to form a return air channel and introduce return air for cooling treatment; S3, mixing the fresh air treated by S1 and the return air treated by S2 at the outlet ends of the fresh air channel and the return air channel to obtain mixed air; S4, sending the mixed air into the treatment area of the rotor for rotor dehumidification treatment to obtain dry air, and sending the dry air into the use area, and the water adsorbed by the rotor is desorbed by regeneration heating.

[0006] Preferably, the cooling and dehumidifying treatment of S1 comprises two-stage treatment of medium-temperature pre-cooling and dehumidification and low-temperature deep cooling and dehumidification.

[0007] Preferably, the heat exchange area of the fresh air medium-temperature surface cooler is greater than the heat exchange area of the return air medium-temperature surface cooler. The heat exchange area of the fresh air low-temperature surface cooler is greater than the heat exchange area of the return air low-temperature surface cooler.

[0008] Preferably, the fresh air channel and the return air channel are respectively provided with independent shutoff air valves and independent cold water regulating circuits.

[0009] Preferably, the control system is further included, which automatically switches the operation mode according to outdoor climate conditions, and the operation mode comprises: summer high humidity mode; spring-autumn-winter dry mode; full fresh air emergency mode.

[0010] Preferably, the summer high humidity mode is to fully open the fresh air channel cold water branch, and simultaneously open the return air channel cold water branch. The spring-autumn-winter dry mode is to open the fresh air channel cold water branch, and shut off or reduce the return air channel cold water supply. The full fresh air emergency mode is to close the return air channel, and to send the processed air into the rotary wheel processing area after cooling treatment of the fresh air channel.

[0011] Preferably, in the summer high humidity mode: The fresh air is pre-cooled to 15℃ by the fresh air medium-temperature surface cooler, and then pre-cooled to 6℃ by the fresh air low-temperature surface cooler. The return air is cooled to 6℃ or 15℃ by the return air medium-temperature surface cooler and the return air low-temperature surface cooler.

[0012] Preferably, in the spring-autumn-winter dry mode, when the moisture content of the fresh air is lower than a set threshold, only the fresh air medium-temperature surface cooler is opened to cool the fresh air to 15℃, and the return air medium-temperature surface cooler and the return air low-temperature surface cooler of the return air channel remain closed.

[0013] (Three) beneficial effects: The fresh air single rotary dehumidification process provided by the application has the following beneficial effects: 1. The fresh air single rotary dehumidification process, by introducing the fresh air and the return air into independent channels respectively and setting the medium-temperature surface coolers and the low-temperature surface coolers respectively, makes the fresh air bear the entire deep dehumidification load, and the return air only needs to be selectively cooled according to actual needs, and the heat exchange area of the return air side surface cooler is selected as 10% to 25% of the fresh air side, thereby avoiding unnecessary deep cooling of the dry return air, and reducing the consumption of invalid sensible heat.

[0014] 2、The new air single-rotary dehumidification process, by setting independent shutoff valves and independent cold water regulating circuits in the new air channel and the return air channel respectively, and configuring a control system that can automatically switch between high humidity mode in summer, dry mode in spring and autumn, and full new air emergency mode according to outdoor climate conditions, thereby realizing independent and accurate regulation and control of the cooling depth of new air and return air, and when the new air humidity load increases sharply in the plum rain season, the new air dehumidification cooling capacity can be increased alone, and when the return air temperature fluctuates in autumn and winter, only the return air side cooling capacity can be adjusted without affecting the new air treatment, greatly improving the operation flexibility under all working conditions.

[0015] 3、The new air single-rotary dehumidification process, by first allowing new air and return air to complete cooling treatment in their respective channels, and then mixing and sending the mixed air into the rotary wheel at the outlet end, the mixed air has a lower humidity content than the traditional mixed air cooled first, thereby reducing the absolute humidity content of the air at the inlet of the rotary wheel, directly reducing the heat energy consumption required for rotary wheel regeneration, and reducing the overall operation cost of the dehumidification system. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 The figure is a process flow diagram of the present application. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present application will be described in detail below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0018] Embodiment one Reference Figure 1 A new air single-rotary dehumidification process according to a preferred embodiment of the present application will be described in detail as follows: A new air single-rotary dehumidification process for mixing and sending new air and return air into a rotary wheel after cooling treatment in their respective channels, comprising the following steps: S1, a new air valve, a new air filter, a new air medium temperature surface cooler and a new air low temperature surface cooler are arranged in sequence along the new air direction to form a new air channel and introduce new air for pre-cooling and cooling dehumidification treatment. Among them: The new air filter is used to intercept dust and particulate matter in outdoor air to prevent them from adhering to the surface of the surface cooler fins and affecting the heat exchange efficiency, and to prevent impurities from entering the rotary wheel treatment area and causing the rotary wheel microchannel to be blocked; The fresh air medium-temperature surface cooler undertakes about 60% to 70% of the sensible heat and part of the latent heat load in the fresh air total heat load, pre-cools the fresh air from 36℃ to about 15℃, and this temperature node corresponds to the rapid drop interval of the fresh air humidity content curve, in which the water vapor condensation rate is the highest, and the dehumidification burden of the downstream low-temperature surface cooler can be effectively reduced.

[0019] S2, a return air valve, a return air filter, a return air medium-temperature surface cooler and a return air low-temperature surface cooler are sequentially arranged in the return air direction to form a return air passage and introduce return air, and the return air is cooled and treated. Among them: The return air filter is used to purify the fiber dust and process waste gas particles carried in the indoor return air, so as to prevent the dust accumulation in the return air side surface cooler coil from causing the wind resistance to rise; The total heat exchange area of the return air medium-temperature surface cooler and the return air low-temperature surface cooler is selected according to 10% to 25% of the rated load of the fresh air side, because the return air humidity content is usually 5.0 to 5.5 g / kg, which is much lower than the humidity content of the fresh air, and almost no condensed water is generated during operation, only a small amount of sensible heat needs to be removed, and considering the cost, the return air medium-temperature surface cooler and the return air low-temperature surface cooler do not need to be configured according to full load amplification.

[0020] S3, the fresh air treated by S1 and the return air treated by S2 are mixed at the air outlet ends of the fresh air passage and the return air passage to obtain mixed air. The specific mixing method is: The air ducts at the outlets of the fresh air medium-temperature surface cooler and the fresh air low-temperature surface cooler and the air ducts at the outlets of the return air medium-temperature surface cooler and the return air low-temperature surface cooler physically converge in the same mixed static pressure box, and the two air flows complete the uniform mixing of the temperature field and the humidity field in the static pressure box. The inside of the static pressure box is provided with a flow guide plate to eliminate the vortex area.

[0021] S4, the mixed air is sent into the treatment area of the wheel for rotary dehumidification treatment to obtain dry air, and the dry air is sent into the use area, and the water adsorbed by the wheel is desorbed by regeneration heating and discharged. Among them: The treatment area of the wheel adopts a honeycomb-shaped moisture absorption medium, and when the mixed air passes through the honeycomb microchannels, the residual water molecules in the air are captured by the adsorbent, and the humidity content of the outlet air can be reduced to below 2.0 g / kg; After the adsorption saturation, the wheel rotates to the regeneration area, and is desorbed by reverse blowing of 70℃ to 85℃ regeneration hot air, and the high-humidity gas desorbed is forcedly discharged to the outside by an exhaust fan.

[0022] The cooling and dehumidification treatment of S1 includes two-stage treatment of medium-temperature pre-cooling and latent moisture and low-temperature deep cooling. Among them: The medium-temperature pre-cooling and latent moisture adopts 10℃ to 13℃ medium-temperature chilled water as the refrigerant to cool the fresh air from 36℃ to 15℃, and in this temperature interval, most of the water vapor (about 60% to 80%) in the fresh air has been condensed and removed as liquid water, and is discharged through the water pan at the bottom of the coil; Low-temperature deep cooling and dehumidification uses 3-5℃ low-temperature chilled water as refrigerant to further cool the fresh air from 15℃ to 6℃, and the remaining residual water vapor is continuously condensed and precipitated, so that the outlet humidity of the fresh air is reduced from about 10.5g / kg to 5.5g / kg. The two-stage temperature difference gradient is designed to avoid the problems of coil surface frosting and heat exchange attenuation when the single surface cooler has a large temperature drop of 30℃.

[0023] The heat exchange area of the fresh air medium-temperature surface cooler is larger than that of the return air medium-temperature surface cooler, and the heat exchange area of the fresh air medium-temperature surface cooler is designed according to the full load condition of processing 36℃, 65%RH fresh air to 15℃, and the coil row number is 6-8 rows, while the return air side medium-temperature surface cooler only needs to process 25℃, 5.2g / kg dry return air to a similar temperature, and the coil row number is 2-3 rows to meet the requirements.

[0024] The heat exchange area of the fresh air low-temperature surface cooler is larger than that of the return air low-temperature surface cooler, and the fresh air low-temperature surface cooler undertakes the dehumidification load from 15℃ deep cooling to 6℃, and the condensate water quantity per unit time is much larger than that of the return air side, so the heat exchange area needs to match the latent heat peak value under the full air quantity of the fresh air, and usually 40%-50% of the area of the fresh air side medium-temperature surface cooler is configured; the return air side low-temperature surface cooler does not need to operate under most conditions, so its heat exchange area can be reduced to 20%-30% of that of the fresh air side low-temperature surface cooler.

[0025] The fresh air channel and the return air channel are respectively provided with independent shutoff air valves and independent cold water regulating circuits, and the air valve leakage rate needs to be controlled within 1% to ensure that there is no air leakage when the fault branch is shut off. The independent cold water regulating circuit specifically refers to that electric regulating valves and flow meters are respectively arranged on the water supply pipelines of the fresh air side surface cooler and the return air side surface cooler, two water supply paths come from different water distributors of the same cold water unit, each path is provided with a hand-operated maintenance gate valve / butterfly valve and a Y-type filter, and when the surface cooling coil is blocked or the valve fails, it can be individually isolated and maintained without affecting the cold water circulation of the other path.

[0026] The control system also includes a PLC controller, an array of temperature and humidity sensors, and an electric actuator. The temperature and humidity sensors are arranged at the inlet of the fresh air and the inlet of the return air to collect air state parameters in real time, and the sampling frequency of the temperature and humidity sensors is not less than 1Hz. The PLC controller needs to have three kinds of PID regulating parameter groups built-in to meet the response speed and overshoot requirements under different conditions. The control system automatically switches the operating mode according to the outdoor climate conditions, and the operating modes include: Summer high humidity mode; Spring and autumn dry mode; Full fresh air emergency mode.

[0027] In the high-humidity summer mode, the chilled water branch of the fresh air duct is fully open, and the chilled water branch of the return air duct is also open. Since the moisture content of the return air is generally below 5.5 g / kg (5.2 g / kg), the corresponding dew point temperature is approximately 5°C. This application cools the return air to 6°C or 15°C, which is above 5°C. Therefore, the return air will not reach its dew point during the cooling process, and no condensate will form. Thus, the chilled water regulating valve in the fresh air duct is fully open, supplying chilled water at the designed peak value. Simultaneously, the chilled water regulating valve in the return air duct is opened to 30%–50% of its opening, providing only a small amount of sensible heat to cool the return air to the set temperature.

[0028] In the spring, autumn, and winter dry mode (where the outdoor fresh air moisture content is generally 8.0–11.0 g / kg), the chilled water branch of the fresh air duct is opened, while the chilled water supply to the return air duct is cut off or reduced. Specifically, the opening of the chilled water regulating valve in the fresh air duct is adjusted to 40%–70%, and the chilled water volume is adjusted in a closed loop based on the real-time detected moisture content at the fresh air outlet; the chilled water regulating valve in the return air duct is completely closed, and the return air is directly bypassed to the mixing section in its original state. Only when the workshop return air temperature is higher than 28℃ is the return air surface cooler slightly opened for temperature compensation to maintain the mixed air temperature within the design range.

[0029] The 100% fresh air emergency mode involves closing the return air duct (a blind flange or airtight valve can be installed at the inlet to ensure a tight seal after closure), cooling the fresh air duct, and then delivering it to the rotary processing area. Specifically, the fresh air duct operates at its maximum designed airflow, with the chilled water valves of both the medium-temperature and low-temperature fresh air surface coolers fully open. The fresh air is then directly delivered to the rotary processing area after two stages of cooling. The 100% fresh air emergency mode is typically used in situations requiring forced ventilation due to a sudden leak of hazardous gases in the workshop, or to maintain the minimum positive pressure requirement in the workshop when the return air fan fails.

[0030] Summer high humidity mode: Since most of the water vapor in the air will be precipitated when the temperature drops from 36°C or above to 15°C, the fresh air is pre-cooled to 15°C by a fresh air medium-temperature surface cooler. The amount of water precipitated when the air continues to cool down from 15°C is significantly less than the amount precipitated when cooling down from 36°C or above. However, since the moisture content at the outlet of the fresh air duct needs to be reduced from about 10.5g / kg to 5.5g / kg before it can be mixed with the return air to meet the requirements of the rotor inlet, it needs to be further pre-cooled to 6°C by a fresh air low-temperature surface cooler. The return air is cooled to 6°C or 15°C via a medium-temperature return air cooler and a low-temperature return air cooler. Since the return air itself has a moisture content of only 5.2 g / kg, far lower than that of the fresh air, it will never reach its dew point during the cooling process, thus preventing condensation. Therefore, cooling the return air to 6°C or 15°C does not affect the moisture content in the mixed air, only its temperature. Therefore, when the workshop has strict requirements for the supply air temperature, cooling the return air to 6°C helps to lower the mixed air temperature. When the workshop has more lenient temperature requirements, cooling the return air to 15°C is sufficient to reduce cooling energy consumption on the return air side. The choice between cooling to 6°C or 15°C depends on the availability of cooling resources that day.

[0031] Since moisture content directly determines whether low-temperature deep dehumidification is needed at the impeller inlet, and although outdoor temperatures are not high in spring, autumn, and winter, humidity can sometimes be high, relying solely on temperature can lead to misjudgments. Therefore, the moisture content of the fresh air is used as the basis for judgment. In the dry mode of spring, autumn, and winter, when the moisture content of the fresh air is lower than the set threshold, it indicates that the fresh air carries little moisture. Simply turning on the medium-temperature surface cooler of the fresh air to cool the fresh air to 15°C is sufficient to reduce the moisture content below the target value. However, turning on the low-temperature surface cooler of the fresh air cannot significantly reduce the moisture content and will instead consume additional low-temperature chilled water. Similarly, since the moisture content of the return air is low, only 5.2 g / kg, the moisture content after mixing with the treated fresh air is still sufficient to meet the impeller inlet requirements. Therefore, the medium-temperature surface cooler and the low-temperature surface cooler of the return air duct are kept closed.

[0032] Example 2 The process is essentially the same as in Example 1, with the only difference being the use of a summer high-humidity mode. The fresh air parameters are 36°C, 65% RH, and a moisture content of approximately 24.7 g / kg, while the return air parameters are 25°C and a moisture content of 5.2 g / kg. In this mode, both the medium-temperature and low-temperature surface coolers for the fresh air are fully operational, and the PLC controller sets the target outlet temperature of the fresh air duct to 6°C. Similarly, both the medium-temperature and low-temperature surface coolers for the return air are also fully operational, with the PLC controller setting the target outlet temperature of the return air duct to 6°C as well. During operation, the fresh air is first pre-cooled to 15°C by the medium-temperature surface cooler, during which a large amount of water vapor condenses and precipitates. It is then further cooled to 6°C by the low-temperature surface cooler, reducing the moisture content at the fresh air outlet to 5.5 g / kg. Since the return air itself has a moisture content of only 5.2 g / kg, almost no condensate is produced during operation. Only the sensible heat load is removed, and the moisture content of the return air remains essentially unchanged after being cooled to 6°C by both the medium-temperature and low-temperature surface coolers. The cooled air from the two streams is mixed at the air outlet to obtain a mixed air with a temperature of 6°C and a moisture content of 5.37 g / kg, which is then sent into the rotary processing area.

[0033] Example 3 The process is essentially the same as in Example 1, with the only difference being: a spring, autumn, and winter drying mode is used, with fresh air parameters of 15°C, 50% RH, and a moisture content of approximately 5.4 g / kg, and return air parameters of 25°C and a moisture content of 5.2 g / kg. In this mode, when the control system detects that the fresh air moisture content is low (below the set threshold), only the fresh air medium-temperature surface cooler in the fresh air duct is activated to cool the fresh air to 15°C, while the fresh air low-temperature surface cooler remains closed; both the return air medium-temperature surface cooler and the return air low-temperature surface cooler in the return air duct remain closed, and the return air participates in the mixing directly at a normal temperature of 25°C. After the fresh air is cooled to 15°C by the fresh air medium-temperature surface cooler, it mixes with the uncooled return air, resulting in a moisture content of approximately 5.3 g / kg, before being sent to the rotary processing area.

[0034] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A fresh air single-rotor dehumidification process, used to introduce fresh air and return air into their respective channels for cooling treatment before mixing and sending them into the rotor, characterized in that, Includes the following steps: S1. A fresh air valve, a fresh air filter, a fresh air medium-temperature surface cooler, and a fresh air low-temperature surface cooler are sequentially installed along the fresh air direction to form a fresh air channel and introduce fresh air for pre-cooling and dehumidification treatment. S2. A return air valve, a return air filter, a return air medium-temperature surface cooler and a return air low-temperature surface cooler are sequentially installed along the return air direction to form a return air channel and introduce return air for cooling treatment. S3. The fresh air treated by S1 and the return air treated by S2 are mixed at the air outlets of the fresh air duct and the return air duct to obtain mixed air. S4. The mixed air is sent into the processing area of ​​the rotor for rotor dehumidification to obtain dry air. The dry air is then sent into the use area, and the moisture adsorbed by the rotor is desorbed and discharged through regeneration heating.

2. The fresh air single-rotor dehumidification process according to claim 1, characterized in that: The cooling and dehumidification process of S1 includes two stages: medium-temperature pre-cooling and dehumidification, and low-temperature deep cooling and dehumidification.

3. The fresh air single-rotor dehumidification process according to claim 1, characterized in that: The heat exchange area of ​​the fresh air medium-temperature surface cooler is larger than that of the return air medium-temperature surface cooler. The heat exchange area of ​​the fresh air low-temperature surface cooler is larger than that of the return air low-temperature surface cooler.

4. The fresh air single-rotor dehumidification process according to claim 1, characterized in that: The fresh air duct and the return air duct are each equipped with an independent shut-off air valve and an independent cold water regulating circuit.

5. The fresh air single-rotor dehumidification process according to claim 1, characterized in that, It also includes a control system that automatically switches operating modes based on outdoor weather conditions, the operating modes including: Summer high humidity mode; Drying mode in spring, autumn and winter; Fresh air emergency mode.

6. The fresh air single-rotor dehumidification process according to claim 5, characterized in that: The summer high humidity mode involves fully opening the cold water branch of the fresh air duct and simultaneously opening the cold water branch of the return air duct. The spring, autumn and winter drying mode involves opening the cold water branch of the fresh air duct and cutting off or reducing the cold water supply to the return air duct. The new fresh air emergency mode involves closing the return air duct and cooling the fresh air duct before sending it into the rotary processing area.

7. The fresh air single-rotor dehumidification process according to claim 5, characterized in that, Under the high humidity mode in summer: The fresh air is pre-cooled to 15°C by the fresh air medium temperature surface cooler, and then further pre-cooled to 6°C by the fresh air low temperature surface cooler; The return air is cooled to 6°C or 15°C by the return air medium-temperature surface cooler and the return air low-temperature surface cooler.

8. The fresh air single-rotor dehumidification process according to claim 5, characterized in that, When the moisture content of the fresh air is lower than the set threshold in the spring, autumn and winter dry mode, only the fresh air medium temperature surface cooler is turned on to cool the fresh air to 15°C, while the return air medium temperature surface cooler and the return air low temperature surface cooler in the return air duct remain closed.

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