Air purification method and device based on spontaneous jumping of condensation droplets on functional surfaces

Abstract

The application discloses an air purification method and device based on spontaneous jumping of condensed droplets on a functional surface. The method utilizes the enhanced super-hydrophobic properties of the functional surface to enable spontaneous jumping of the condensed droplets when the environmental water vapor condenses on the low-temperature functional surface of the heat exchanger, thereby continuously and efficiently ejecting the tiny droplets into the air. The method simulates the rainfall process to adsorb, agglomerate and remove aerosol particles in the indoor air. The condensed droplets can obtain high-density micro-energies such as surface energy, kinetic energy and electric energy during condensation and jumping, and through the synergistic effect of inertial collision, interception and thermophoresis capture mechanisms, high-efficiency capture of the suspended particles in the air is formed. The spontaneously generated hydrogen peroxide of the condensed droplets also has a purification function of disinfection and sterilization, which can reduce the risk of virus and bacteria transmission in the indoor environment. The method provides a new scheme of low cost, high efficiency, no filter components and additional energy consumption for the purification of indoor air and fresh air.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of air purification, and in particular to an air purification method and device based on spontaneous jumping of condensed droplets on a functional surface. BACKGROUND

[0002] PM2.5 particulate matters suspended in the air are very easy to adsorb toxic and harmful substances (such as heavy metals, microorganisms, aromatic compounds, etc.), and can enter the lungs by breathing, thereby affecting the respiratory and cardiovascular systems and causing great harm to human health. At present, the methods for reducing the concentration of indoor suspended particles mainly include two technologies: medium filtration and electrostatic filtration. However, in the long-term operation process, it is necessary to continuously invest energy, regularly clean and maintain, or replace the filter components, which is not conducive to the implementation of the national energy-saving and emission-reducing strategy.

[0003] Rainfall is the simplest and most direct way to purify air and remove suspended particles from the atmospheric ecological system. The wet dust removal technology that simulates the natural rainfall process has been widely used in the removal of ultra-fine particles in industrial waste gas. However, the commonly used water vapor condensation and water mist spraying methods consume a large amount of water resources, heat energy or electric energy, which limits the application of wet dust removal technology in the field of indoor air purification.

[0004] In recent years, people's demand for health and safety is increasing, and the country continues to emphasize the coordinated promotion of energy saving and consumption reduction and pollution prevention and control of the whole society. Therefore, there is an urgent need for a new type of indoor air purification technology that is low-cost, high-efficiency and energy-saving. SUMMARY

[0005] Therefore, the present application provides an air purification method and device based on spontaneous jumping of condensed droplets on a functional surface, which can provide a new solution for indoor air and fresh air purification that is low-cost, high-efficiency, does not require filter components and additional energy consumption.

[0006] In a first aspect, the present application provides an air purification method based on spontaneous jumping of condensed droplets on a functional surface. The functional surface is constructed outside the heat absorption component of a heat exchanger. The phenomenon of spontaneous jumping of condensed droplets on the functional surface with lower temperature simulates the rainfall process to adsorb, agglomerate and remove aerosol particles in the air, thereby achieving the purification of indoor air and fresh air.

[0007] Optionally, the functional surface is used to make the micro-condensed droplets jump spontaneously, including a binary surface with mixed wetting properties and a super-hydrophobic surface with nano-structure or micro-nano level structure.

[0008] In this way, the metastable liquid bridge formed when the condensed droplets merge hits the functional surface, causing the droplets to gain effective kinetic energy for upward movement, thereby promoting the spontaneous jumping of the droplets and improving the condensation heat transfer rate of the surface.

[0009] Optionally, the heat exchanger absorbs heat from the environment when in operation.

[0010] Optionally, the heat exchanger comprises an air conditioner, a dehumidifier or an air cooler.

[0011] In this way, a functional surface is constructed outside the heat-absorbing component of the heat exchanger, the first aspect utilizes the temperature difference between the environment and the low-temperature functional surface to realize the spontaneous jumping phenomenon of the condensed droplets, greatly reducing the consumption of high-grade energy and water resources; the second aspect, the functional surface can greatly reduce the barrier of water vapor condensation and nucleation on the surface, and can also regulate the condensation position of the droplets to reduce the interfacial adhesion, effectively improving the condensation rate and self-jumping ability of the droplets; the third aspect, in a low-humidity environment, micro-scale jumping condensed droplets can still be continuously and efficiently generated to simulate the rainfall process; the fourth aspect, the wettability and hierarchical structure affect the interfacial thermal resistance of the droplets and the surface, and the small droplets can be detached from the surface by jumping, which can play a role in preventing icing in a low-temperature environment without reducing the condensation heat exchange efficiency; the fifth aspect, without the need for a separate air purifier.

[0012] Optionally, the size of the condensed droplets spontaneously jumping on the functional surface is only 10-100 μm, with a high density of surface energy.

[0013] Optionally, the condensed droplets spontaneously jumping on the functional surface obtain a high density of electric energy during the process of water vapor condensation and jumping, with a charge-to-mass ratio exceeding 100 C / kg.

[0014] Optionally, the condensed droplets on the functional surface spontaneously generate hydrogen peroxide during the process of water vapor condensation and jumping.

[0015] In this way, the jumping condensed droplets greatly improve the capture efficiency of aerosol particles in the air through the coupling of strong electrostatic adsorption with thermophoresis and diffusion phoresis capture mechanisms, as well as the interaction between multiple droplets. The hydrogen peroxide spontaneously generated by the condensed droplets can also disinfect and sterilize indoor air such as hospital rooms and operating rooms, reducing the risk of virus and bacteria transmission indoors.

[0016] The second aspect of the present application provides an air purification device based on the spontaneous jumping of condensed droplets on a functional surface, which is provided with a functional surface outside the heat-absorbing component of the heat exchanger that can make the condensed droplets spontaneously jump. The temperature of the functional surface is lower than the surrounding environment, so as to simulate the rainfall process to absorb, agglomerate and remove aerosol particles in the air.

[0017] In a third aspect, the present application provides an air conditioning system, comprising an indoor unit evaporator, and a functional surface outside the indoor unit evaporator, which can make condensate droplets spontaneously bounce, and the temperature of the functional surface is lower than the surrounding environment, so that the phenomenon of making condensate droplets spontaneously bounce simulates the process of rainfall to adsorb, agglomerate and remove aerosol particles in the air.

[0018] In a fourth aspect, the present application provides an air conditioning system, comprising an outdoor unit condenser, and a functional surface outside the outdoor unit condenser, which can make condensate droplets spontaneously bounce, and the temperature of the functional surface is lower than the surrounding environment, so that the phenomenon of making condensate droplets spontaneously bounce simulates the process of rainfall to adsorb, agglomerate and remove aerosol particles in the air.

[0019] In a fifth aspect, the present application provides a dehumidifier, comprising a dehumidifier evaporator, and a functional surface outside the dehumidifier evaporator, which can make condensate droplets spontaneously bounce, and the temperature of the functional surface is lower than the surrounding environment, so that the phenomenon of making condensate droplets spontaneously bounce simulates the process of rainfall to adsorb, agglomerate and remove aerosol particles in the air.

[0020] The present application has the following beneficial effects:

[0021] 1. Using the temperature difference of the heat absorption part of the environmental and indoor heat exchanger (such as air conditioner, dehumidification equipment, etc.), condensation bounce droplets can be continuously and efficiently generated on the low-temperature functional surface in a low-humidity environment, realizing simulated rainfall dust removal, without the need for additional air purifiers, filtering components and artificial maintenance, greatly reducing the consumption of high-grade energy and water resources.

[0022] 2. The condensate droplets obtain high-density surface energy, kinetic energy, electrical energy and chemical energy and other micro-energies in the process of water vapor condensation and spontaneous bouncing, and through the coupling of strong electrostatic adsorption, thermophoresis force and diffusion thermophoresis force and other trapping mechanisms, as well as the interaction between multiple droplets, the particle trapping efficiency can be greatly improved, realizing efficient air purification.

[0023] 3. The condensate droplets spontaneously generate hydrogen peroxide, which can disinfect and sterilize indoor air such as sickrooms and operating rooms, reducing the risk of virus and bacteria transmission indoors, and is a non-odor, zero-cost and highly universal air disinfection and sterilization method.

[0024] 4. The functional surface is constructed outside the heat absorption part of the heat exchanger, which mixes the wettability and hierarchical structure to affect the interfacial thermal resistance of the droplets and the surface, and the small droplets can bounce off the surface, which can prevent icing in a low-temperature environment without reducing the condensation heat transfer efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0025] The technical solutions and other beneficial effects of the present application will become apparent from the following detailed description of specific embodiments of the present application, combined with the accompanying drawings.

[0026] Figure 1 Scanning electron microscope image of the functional surface of the present application.

[0027] Figure 2 Schematic diagram of the present application for capturing suspended micro-particles by bouncing condensate droplets with multi-energy characteristics.

[0028] Figure 3 Schematic diagram of the present application for various particle capture mechanisms of the bouncing condensate droplet phase transition interface.

[0029] Figure 4 Schematic diagram of the present application for the process of bouncing condensate droplets capturing gas suspended micro-particles.

[0030] Figure 5 Principle diagram of the present application for enhanced condensation and anti-icing of the functional surface.

[0031] Figure 6 Structural schematic diagram of the present application for air purification using an air conditioner.

[0032] Figure 7 Structural schematic diagram of the present application for air purification using a dehumidifier.

[0033] In the drawings, the elements in the figures are identified as follows:

[0034] 1 - functional surface; 11 - binary surface; 12 - nanosheet superhydrophobic surface; 13 - nanorod superhydrophobic surface; 14 - superhydrophobic nanowire; 15 - hydrophilic micropillar array; 2 - condensate droplet; 21 - positive charge; 22 - hydrogen peroxide; 23 - kinetic energy; 24 - surface energy; 3 - suspended particulate matter; 4 - air conditioner; 41 - indoor unit evaporator; 42 - outdoor unit condenser; 5 - dehumidifier; 51 - dehumidifier evaporator. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0036] In the description of the application, it is necessary to understand that the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can be explicitly or implicitly included one or more of the features. In the description of the application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0037] In the description of the application, it should be noted that unless otherwise expressly specified and limited, the terms "mounting", "connecting", "connecting" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection or can communicate with each other; it can be directly connected, or indirectly connected through intermediate medium, it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0038] The following disclosure provides many different embodiments or examples for implementing different structures of the application. In order to simplify the disclosure of the application, the components and arrangements of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the application. In addition, the application can repeatedly refer to numbers and / or letters in different examples. Such repetition is for the purpose of simplification and clarity, and in itself does not indicate the relationship between the various embodiments and / or arrangements discussed. In addition, the application provides various specific examples of processes and materials, but those skilled in the art can realize the application of other processes and / or the use of other materials.

[0039] Figure 1 Various functional surfaces 1 are given, including binary surfaces 11 with mixed wetting properties, nanosheet superhydrophobic surfaces 12, and nanorod superhydrophobic surfaces 13. Take the binary surface 11 as an example, the functional surface 1 with mixed wetting properties is composed of superhydrophobic nanowires 14 and hydrophilic micropillar arrays 15. The condensation droplets 2 are first condensed on the hydrophilic micropillar array 15 and form a liquid film, which gradually changes into a bead-shaped condensation when growing under the restriction of the superhydrophobic nanowires 14. Finally, the metastable liquid bridge formed by the coalescence of the condensation droplets 2 hits the surface, resulting in the condensation droplets 2 gaining kinetic energy 23 upward, and then realizing the spontaneous bouncing of the condensation droplets 2. The binary surface 11 not only reduces the barrier of water vapor condensation nucleation on the surface, but also regulates the condensation position of the condensation droplets 2 to reduce the interfacial adhesion, effectively improving the condensation rate and self-bouncing ability of the condensation droplets 2. Therefore, using the functional surface 1 can continuously and efficiently generate microscale bouncing condensation droplets 2 to simulate the rainfall process.

[0040] Figure 2 A schematic diagram illustrating the various micro-energies possessed by the bouncing condensate droplets 2 and the process of capturing suspended microparticles 3 is presented. The process of water vapor condensation on the functional surface 1 gives the condensate droplets 2 surface energy 24 and bouncing kinetic energy 23, and since the size of the condensate droplets 2 is only 10~100 μm, it has a higher surface energy 24. Due to the presence of an electric double layer at the solid-liquid interface between the condensate droplets 2 and the functional surface 1, the bouncing process of the condensate droplets 2 detaching from the surface causes charge separation, resulting in the bouncing condensate droplets 2 carrying a positive charge 21. By continuously bouncing a considerable number of charged condensate droplets 2 with small radius, high speed, and high charge-to-mass ratio into the air using the functional surface 1, a rainfall process is simulated to adsorb, aggregate, and remove suspended particulate matter 3 from the air.

[0041] Furthermore, the strong electric field generated by the double layer at the solid-liquid interface causes hydrogen peroxide 22 to form within the condensate droplet 2, which can disinfect and sterilize the air in indoor spaces such as wards and operating rooms, reducing the risk of virus and bacteria transmission indoors. The disinfection and sterilization function of the bouncing condensate droplet 2 has the advantages of being odorless, cost-free, and highly versatile.

[0042] like Figure 3 and Figure 4 As shown, bouncing condensate droplets 2 come into contact with the airflow and adsorb and capture suspended particulate matter 3 in the airflow through mechanisms such as Brownian diffusion, inertial collision, and interception. Suspended particulate matter 3 undergoes random Brownian motion in the airflow, colliding with condensate droplets 2 during this process; this capture method is Brownian diffusion. When suspended particulate matter 3 flows around condensate droplets 2, it passes through streamlines due to its own inertia and impacts the surface of condensate droplets 2; this is inertial collision. Suspended particulate matter 3 collides with the surface of condensate droplets 2 as it moves towards them with the gas; this is interception. The charge-to-mass ratio of bouncing condensate droplets 2 can exceed 100 C / kg, exhibiting strong electrostatic adsorption of suspended particulate matter 3. A temperature difference exists between the airflow and condensate droplets 2, causing suspended particulate matter 3 to migrate towards condensate droplets 2 under the influence of thermophoretic and diffusive forces. Through the synergistic effect of strong electrostatic adsorption, thermophoretic and diffusive forces, and the interaction between multiple condensate droplets 2, the capture efficiency of suspended particulate matter 3 (such as atmospheric aerosols) can be significantly improved.

[0043] Figure 5The principle of the functional surface 1 for strengthening condensation and preventing icing is illustrated by taking the binary surface 11 as an example. The mixed wettability and the micro-nano hierarchical structure simultaneously enhance the condensation heat transfer and the anti-icing ability of the binary surface 11, which is affected by the changing interfacial thermal resistance during the growth of the condensation droplets 2. The water vapor in the air condenses rapidly at the top of the hydrophilic micropillar array 15 and releases phase change heat, effectively strengthening the condensation heat transfer. For the superhydrophobic nanowire 14 region, the condensation droplets 2 first nucleate in the interstitial gap, form a partial Wenzel state by locally wetting the nanocavity, and reduce the thermal resistance below the small condensation droplets 2 to enhance the overall heat transfer. As the condensation droplets 2 grow and coalesce, the binary surface 11 exhibits superhydrophobic non-wettability, reducing the heat transfer rate between the condensation droplets 2 and the surface, and preventing the condensation droplets 2 from further cooling and icing. In addition, the spontaneous jumping phenomenon of the condensation droplets 2 on the binary surface 11 further enhances the anti-icing ability. Embodiment One

[0045] The liquid refrigerant enters the indoor unit evaporator 41 of the air conditioner 4, and the increase in space and decrease in pressure cause the refrigerant to vaporize and absorb heat, realizing the refrigeration function of the air conditioner. As shown in Figure 6 , the indoor air flows through the indoor unit evaporator 41, and the functional surface 1 constructed by the indoor unit evaporator 41 and its fins can promote the efficiency of condensing water vapor, simulate the rainfall process using the spontaneous jumping phenomenon of the condensation droplets 2, and purify the fresh air of the air conditioner 4 based on the wet dust removal principle. At the same time, using the spontaneously generated hydrogen peroxide 22 of the condensation droplets 2, the indoor fresh air is disinfected and sterilized, effectively reducing the infection risk of indoor environments such as hospital rooms.

[0046] The heating process of the air conditioner 4 is opposite to the refrigeration process, and the surface of the outdoor unit condenser 42 is prone to icing in low temperature environments, limiting the heating effect of the air conditioner 4. The functional surface 1 is constructed outside the outdoor unit condenser 42 Figure 6 , the interfacial thermal resistance between the condensation droplets 2 and the surface is affected by the change in wettability; at the same time, small-scale condensation droplets 2 can jump off the surface, cooperatively improving the condensation heat transfer efficiency and anti-icing ability of the outdoor unit condenser 42. The air conditioner 4 with the outdoor unit condenser 42 having the functional surface 1 can heat instantly without defrosting in low temperature environments, while effectively ensuring the heating effect. Embodiment Two

[0048] The working principle of the dehumidifier 5 for reducing indoor humidity is similar to that of the air conditioner 4 for refrigeration. The water vapor in the air condenses into liquid water when it encounters the low-temperature dehumidifier evaporator 51, and the dry air after drying by the dehumidifier condenser is discharged from the air outlet. As shown in Figure 7, In the dehumidifier evaporator 51 and its fin construction function surface 1, on the one hand, the function surface 1 with high condensation heat transfer efficiency helps to improve the water vapor condensation efficiency and improve the dehumidification effect of the dehumidifier 5; on the other hand, the function surface 1 simulates the rainfall process to capture the suspended particulate matter 3 in the air, and synchronously realizes the functions of air purification and disinfection and sterilization.

[0049] In addition, in a low temperature environment, the dehumidifier fails due to the frost formation on the surface of the dehumidifier evaporator 51. The function surface 1 outside the dehumidifier evaporator 51 improves the anti-icing ability by affecting the interfacial thermal resistance between the condensate droplets 2 and the surface, without reducing the condensation heat transfer efficiency. Therefore, the dehumidifier 5 with the function surface 1 can still work normally in a low temperature environment.

[0050] The above is only the preferred specific embodiment of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed in the present application, which should be covered within the protection scope of the present application.

Claims

1. An air purification method based on the spontaneous jumping of condensed droplets on a functional surface, characterized in that, The functional surface is constructed outside the heat absorption component of the heat exchanger, and the condensate droplets spontaneously jump on the functional surface with lower temperature to simulate the rainfall process to adsorb, agglomerate and remove the aerosol particles in the air, thereby purifying the indoor air and fresh air. The functional surface is a binary surface with mixed wetting characteristics, which is composed of super-hydrophobic nanowires and hydrophilic micropillar arrays; the condensate droplets are first condensed on the hydrophilic micropillar arrays to form liquid films, and the liquid films gradually change into bead-shaped condensation when growing and are limited by the super-hydrophobic nanowires; finally, the metastable liquid bridges formed by the combined condensate droplets impact the surface, so that the droplets obtain kinetic energy for upward movement to realize spontaneous jumping. The condensate droplets and the functional surface have a double electric layer at the solid-liquid interface, and the process of the condensate droplets jumping off the surface causes charge separation, so that the jumping condensate droplets have positive charges. The condensate droplets obtain high-density surface energy, kinetic energy, electric energy and chemical energy in the process of water vapor condensation and spontaneous jumping, and capture the aerosol particles through the coupling of strong electrostatic adsorption, thermophoretic force and diffusiophoretic force capture mechanisms, and simultaneously generate hydrogen peroxide spontaneously in the above process to disinfect and sterilize the air.

2. The method of claim 1, wherein, The temperature of the heat absorption component of the heat exchanger is lower than the environment when working.

3. The method of claim 1, wherein the air purification method is characterized by, The heat exchanger includes an air conditioner, a dehumidifier or a cold air machine.

4. The method of claim 1, wherein the air purification method is characterized by, The size of the condensate droplets spontaneously jumping on the functional surface is 10-100 μm, and the condensate droplets have high-density surface energy.

5. The method of claim 1, wherein the air purification method is characterized by, The condensate droplets spontaneously jumping on the functional surface obtain high-density electric energy in the process of water vapor condensation and jumping, and the charge-to-mass ratio exceeds 100 C / kg. The condensate droplets on the functional surface spontaneously generate hydrogen peroxide in the process of water vapor condensation and jumping.

6. An air purification device based on the spontaneous jumping of condensed droplets on a functional surface, characterized in that, A functional surface that can make condensate droplets spontaneously jump is constructed outside the heat absorption component of the heat exchanger, the temperature of the functional surface is lower than the surrounding environment, and the phenomenon of condensate droplets spontaneously jumping simulates the rainfall process to adsorb, agglomerate and remove the aerosol particles in the air.

7. An air conditioning system characterized by, An indoor unit evaporator is provided with a functional surface that can make condensate droplets spontaneously jump outside the indoor unit evaporator, the temperature of the functional surface is lower than the surrounding environment, and the phenomenon of condensate droplets spontaneously jumping simulates the rainfall process to adsorb, agglomerate and remove the aerosol particles in the air.

8. An air conditioning system characterized by, An outdoor unit condenser is provided with a functional surface that can make condensate droplets spontaneously jump outside the outdoor unit condenser, the temperature of the functional surface is lower than the surrounding environment, and the phenomenon of condensate droplets spontaneously jumping simulates the rainfall process to adsorb, agglomerate and remove the aerosol particles in the air.

9. A dehumidifier, characterized by A dehumidifier evaporator is provided with a functional surface that can make condensate droplets spontaneously jump outside the dehumidifier evaporator, the temperature of the functional surface is lower than the surrounding environment, and the phenomenon of condensate droplets spontaneously jumping simulates the rainfall process to adsorb, agglomerate and remove the aerosol particles in the air.

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