A side-mounted segmented circulating air curtain device for cold storage

Abstract

The present application relates to a kind of side-mounted segmented circulating air curtain device for cold storage, including air outlet pipe section, air outlet, air return, air return pipe section and air return circulating pipe section, air outlet is the multiple air outlet of vertical installation in the one side of cold storage door frame, air return is set in the opposite side of cold storage door frame;Air flow that air outlet pipe section blows out through air outlet, after passing through cold storage door, is introduced into air return, is converged after air return pipe section, and is introduced back to air outlet pipe section by air return circulating pipe section, forms the air circulation in air curtain interior;Wherein, according to the thermal pressure distribution characteristics of cold storage door, the air outlet volume and air outlet angle of each air outlet section are set, and each air outlet section is independently controlled;Segmented air outlet satisfies: the width of each segmented air outlet remains unchanged, changes the air outlet speed of each segmented air outlet;Or the air outlet speed of each segmented air outlet remains unchanged, changes the width of each segmented air outlet.Compared with prior art, the present application can more efficiently block the heat transfer at the cold storage door, with the characteristics of energy saving and high efficiency.

Description

Technical Field

[0001] This invention relates to the field of air curtain devices, and in particular to a side-mounted segmented circulating air curtain device for cold storage. Background Technology

[0002] When cold storage doors are frequently or for extended periods, the thermal pressure caused by the temperature difference between indoors and outdoors allows hot, humid outdoor air to enter the cold storage room through the door. This significantly increases the infiltration load and affects the stability of the indoor environment. To reduce heat and mass exchange between the indoor and outdoor environments, cold storage door air curtains are a widely used and important energy-saving technology. They offer the advantages of not obstructing the view of personnel or interfering with the passage of people and vehicles during operation.

[0003] Existing air curtain devices are mostly vertically upward-flowing, installed in the upper space of cold storage doors. They primarily use a cross-flow fan (or centrifugal fan) within the casing to create a planar turbulent jet structure through strip-shaped air outlets, achieving gas dynamic sealing of the cold storage door. Based on the theory of natural ventilation under thermal pressure, the infiltration flow driven by the indoor-outdoor temperature difference exhibits a characteristic of being weak in the middle and strong at both ends along the height direction. However, the velocity decay during jet development is inconsistent with the thermal pressure gradient along the height direction.

[0004] Existing cold storage door air curtain designs do not consider the impact of vertical thermal pressure gradient changes. Vertically supplied air curtain jets often experience significant velocity reduction upon reaching the ground, failing to resist strong infiltration flow at the ground level and thus deteriorating the air curtain's barrier effect. Furthermore, given the limited installation space above the cold storage door, vertically supplied air curtains are no longer suitable, necessitating the installation of horizontally supplied air curtain devices on the side of the door frame. The jet trajectory of a side-mounted horizontally supplied air curtain does not need to traverse the entire cold storage door plane; it only needs to resist varying degrees of thermal pressure at different heights, offering a natural advantage in preventing heat exchange between the inside and outside of the cold storage door.

[0005] A search revealed that Chinese utility model patent CN217330169U discloses an air curtain structure. The air curtain is a side-mounted, horizontally supplied airflow type, with three horizontal baffles at the air outlet of the outer casing. Each baffle has a different angle, adjusting the initial angle between the air curtain jet and the horizontal direction. This utility model is suitable for applications with limited installation space at the top of cold storage doors. However, the patent's method of using horizontal baffles at the air outlet to create an initial vertical outflow angle for the air curtain is not suitable for the barrier requirements under conditions of large temperature differences between indoors and outdoors, such as in cold storage facilities.

[0006] Chinese invention patent application CN101915447A discloses a method for forming an air curtain. The air curtain is formed by simultaneously setting air outlets on both sides of the door frame for horizontal airflow, and setting the outlet angle and velocity on both sides respectively, so that the two planar jets together form a sealing structure against the door, effectively preventing the mixing of indoor and outdoor air. This method is suitable for situations where the installation space at the top of the cold storage door is limited. However, since the airflow parameters of the two outlets are consistent in the vertical direction, the different thermal pressures at different heights make it easy for the two opposing airflows to interfere with each other, making it difficult to form a complete and effective sealing structure.

[0007] Furthermore, existing side-mounted air curtain design methods typically only require a certain air outlet velocity range, such as no more than 8 m / s for exterior doors of production plants and no more than 25 m / s for tall exterior doors. The lack of accurate quantitative calculation expressions for airflow makes it difficult to accurately select the appropriate fan for the air curtain equipment.

[0008] Therefore, there is an urgent need to design a side-mounted circulating air curtain device for cold storage with better heat and mass transfer barrier effect at the cold storage door. Summary of the Invention

[0009] The purpose of this invention is to overcome the shortcomings of the prior art by providing a side-mounted segmented circulating air curtain device for cold storage. The outflow parameters of the air curtain are set according to the thermal pressure distribution characteristics at the cold storage door, which can more effectively block heat and mass transfer at the cold storage door and has the characteristics of energy saving and high efficiency.

[0010] The objective of this invention can be achieved through the following technical solutions:

[0011] This invention provides a side-mounted segmented circulating air curtain device for cold storage, used to block heat exchange between the cold storage and the external environment. The device includes an air outlet section, an air outlet, a return air outlet, a return air section, and a return air circulation section. The air outlet is a multi-segment air outlet installed vertically on one side of the cold storage door frame, and the return air outlet is located on the opposite side of the cold storage door frame.

[0012] The airflow blown out of the air outlet of the air outlet section passes through the cold storage door and enters the return air inlet. After converging through the return air section, it returns to the air outlet section through the return air circulation section, forming air circulation inside the air curtain. The airflow volume and airflow angle of each air outlet section are set independently according to the thermal pressure distribution characteristics at the cold storage door.

[0013] The segmented air outlets satisfy the following conditions: the width of each segmented air outlet remains constant, and the air outlet speed of each segmented air outlet is changed to control the air volume of each segmented air outlet; or the air outlet speed of each segmented air outlet remains constant, and the width of each segmented air outlet is changed to control the air volume of each segmented air outlet.

[0014] Preferably, the width of each segment air outlet remains constant, and the air outlet speed of each segment air outlet is changed to control the air volume of each segment air outlet;

[0015] The segmented air outlet is equipped with a variable frequency fan controller, a speed-regulating motor, and a variable frequency fan; the variable frequency fan controller is connected to the speed-regulating motor and is used to control the flow rate of the variable frequency fan, forming an independent air outlet segment fan control unit; the number of air outlet segment fan control units is the same as the number of air outlet segments and corresponds one-to-one, so as to independently control the air volume of each air outlet segment.

[0016] Preferably, the air velocity of each segment air outlet remains constant, while the width of each segment air outlet is changed to control the air volume of each segment air outlet.

[0017] Preferably, the air outlet is provided with a variable frequency fan controller, a speed regulating motor and a variable frequency fan, the variable frequency fan controller is connected to the speed regulating motor and is used to control the flow rate of the variable frequency fan; the air outlet is also provided with an air outlet rectification module to ensure that the speed of each segment of the air outlet is evenly distributed.

[0018] Preferably, the segmented air outlets are equipped with a temperature control module triggered by a temperature difference threshold, which is used to control the air outlet temperature of each segment of the air outlet to satisfy the following conditions: the air outlet temperature of each segment above the neutral plane is lower than the air outlet temperature of each segment below the neutral plane, and the air outlet temperature of each segment is not increased from the neutral plane towards the highest segment, and the air outlet temperature of each segment is not decreased from the neutral plane towards the lowest segment.

[0019] Preferably, each air outlet is equipped with an adjustable and fixed guide vane, and a guide vane controller corresponding to each air outlet guide vane. The air outlet angle of each air outlet is adjusted by the guide vane controller. The air outlet angle is the angle between the guide vane and the plane of the cold storage door.

[0020] Preferably, baffles are provided on both sides of the return air inlet along the height direction to prevent the air curtain jet from overflowing into the cold storage space after reaching the return air inlet without being collected.

[0021] Preferably, the return air inlet is a segmented return air inlet, corresponding one-to-one with the segmented air outlet; the guide baffle is an adjustable arc-shaped guide baffle, and the deflection direction of the arc-shaped guide baffle is consistent with the air outlet angle direction of the corresponding segment air outlet, that is, both deflected towards the inside of the cold storage or both deflected towards the outside of the cold storage.

[0022] Preferably, the air outlet is a segmented rectangular air outlet, the return air outlet is a rectangular return air outlet, and the width of the return air outlet is not less than the width of the air outlet.

[0023] Preferably, a return air filter is provided in the return air circulation pipe section.

[0024] Preferably, the process of setting the air volume and air outlet angle for each air outlet section includes:

[0025] 1) Obtain the height H and width W of the cold storage door, the width B of the air curtain outlet, and the temperature T inside the cold storage. c and the ambient temperature T w ;

[0026] 2) Based on the relationship between the thermal pressure on both sides of the cold storage door and the air curtain jet flow rate, the calculation expression for the total air curtain volume Q was derived through experimental simulation:

[0027]

[0028] In the formula, γ, ω, β, λ, and δ are the fitting parameters, respectively;

[0029] 3) Based on the thermal pressure that each air outlet needs to withstand and the center height of each air outlet, calculate the ratio of the thermal pressure that each air outlet needs to withstand to allocate the air volume of each air outlet. Then, based on the air volume of each air outlet, determine the air velocity of each air outlet or the width of each air outlet.

[0030] 4) Based on the magnitude and direction of the thermal pressure corresponding to each air outlet, determine the magnitude and direction of the air outlet angle for each air outlet. The air outlet angle direction satisfies the following: symmetrically opposite along the middle height of the cold storage door, with the air outlets above the neutral plane facing outwards from the cold storage, and the air outlets below the neutral plane facing inwards from the cold storage. The air outlet angle magnitude satisfies the following: symmetrically equal along the middle height of the cold storage door, with the middle section having the smallest air outlet angle and the highest and lowest sections having the largest air outlet angles. The air outlet angles for each air outlet are then allocated accordingly.

[0031] Preferably, in step 3), based on the magnitude of the thermal pressure that each air outlet section needs to withstand and the center height of each air outlet section, the ratio of the thermal pressure that each air outlet section needs to withstand is calculated to allocate the airflow of each air outlet section. Then, based on the airflow of each air outlet section, the airflow velocity of each air outlet section or the width of each air outlet section is determined, specifically:

[0032] According to the thermal pressure ΔP1 corresponding to the center height h1 of the segmented air outlet, ΔP1 = (ρ w -ρ c )g(h1-H n The center height h of the segmented air outlet n Corresponding hot pressure: ΔP n =(ρ w -ρ c )g(h n -H nThe center height h1 of the segmented air outlet and the center height h of the segmented air outlet can be determined. n The corresponding hot-press ratio is Among them, H n ρ is the height of the neutral surface. w ρ c These represent the ambient air density and the air density inside the cold storage, respectively; g is the gravitational acceleration at the Earth's surface.

[0033] According to the ratio of thermal pressure, which is equal to the ratio of air curtain flow rate. Obtain the center height h1 of the segmented air outlet and the center height h of the segment. n The formula for calculating the relationship between flow rate and bandwidth: Among them, u1, u n These are the center heights of the segmented air outlets, h1 and h, respectively. n Corresponding air outlet speeds; B1, B n These are the segment center height h1 and segment center height h, respectively. n The corresponding air outlet width; Q1 represents the center height h1 and center height h of the segmented air outlets, respectively. n The corresponding air volume.

[0034] Compared with the prior art, the present invention has the following advantages:

[0035] 1) For applications such as cold storage where there is a large temperature difference between indoors and outdoors, this invention installs multiple air outlets vertically on one side of the door frame and independently adjusts the air curtain jet parameters (air volume and angle) at different heights. This better addresses the vertical distribution characteristics of heat pressure at the cold storage door. The jet trajectory of the side-mounted horizontal air supply air curtain does not need to cross the entire cold storage door plane, but only needs to resist different amounts of heat pressure at different heights. It has a natural advantage in blocking heat exchange between the inside and outside of the cold storage door.

[0036] 2) The width of each segment air outlet remains unchanged. The air outlet speed of each segment air outlet is changed to control the air volume of each segment air outlet. Each segment is controlled separately by an independent air outlet section fan control unit composed of a variable frequency fan controller, a speed regulating motor and a variable frequency fan mechanism. The independent controller setting ensures the control effect, and the segmented control setting further reduces the maintenance cost of the side-mounted segmented circulating air curtain device for cold storage in case of subsequent failure.

[0037] 3) The air velocity of each segment air outlet remains constant. Only the width of each segment air outlet needs to be set to control the air volume of each segment air outlet. There is no need to set the air velocity of each segment air outlet separately, which is more convenient.

[0038] 4) The air outlet of each section is controlled by the guide vanes to control the air outlet angle in segments, which ensures the control effect. The segmented control setting also further reduces the maintenance cost of the side-mounted segmented circulating air curtain device for cold storage in case of subsequent failure.

[0039] 5) Setting up return air vents and return air ducts enables air circulation inside the air curtain, which can recover the cold energy carried by the air curtain jet and further reduce the energy consumption of the cold storage.

[0040] 6) A temperature control module based on temperature difference threshold is installed in the segmented air outlets to control the air outlet temperature of each segment. The air outlet temperature of each segment above the neutral plane is lower than that of each segment below the neutral plane. Furthermore, the air outlet temperature of each segment is not increased from the neutral plane towards the highest segment, and is not decreased from the neutral plane towards the lowest segment. This effectively addresses the infiltration winds encountered when warm air above the neutral plane flows from the outside into the cold storage room and cold air below the neutral plane flows from the cold storage room to the outside, further reducing the energy consumption of the cold storage.

[0041] 7) Install a baffle along the height of the side of the return air vent to prevent the air curtain jet from overflowing after reaching the return air vent and directly entering the cold storage space, thereby reducing energy consumption.

[0042] 8) The return air inlet is a segmented return air inlet, which corresponds one-to-one with the segmented air outlet. The guide baffle is an adjustable arc-shaped guide baffle. The direction of the arc-shaped guide baffle is consistent with the direction of the air outlet angle of the corresponding segment, that is, it is simultaneously biased towards the inside of the cold storage or simultaneously biased towards the outside of the cold storage, which can achieve a better air curtain jet collection effect and reduce energy consumption.

[0043] 9) A return air filter is installed in the return air circulation pipe section, which further improves the clean, safe and stable operation of the circulating air curtain device.

[0044] 10) Based on computer simulation and other results, this invention has conducted a detailed study on the parameters of the side-mounted segmented circulating air curtain, and based on a more accurate calculation expression for the air curtain air volume, it provides guidance for the accurate selection of the fan for the air curtain equipment.

[0045] 11) Based on the thermal pressure distribution characteristics at the cold storage door, this invention independently controls the air volume and air angle of each air outlet section, clarifies the optimization direction of the air curtain outflow parameters under different thermal pressure conditions, realizes the optimal air outlet parameter design, and can achieve the best heat and mass transfer barrier effect at the cold storage door. Attached Figure Description

[0046] Figure 1 The diagram shows the infiltration air passing through the cold storage door under thermal pressure; (a) is a schematic diagram of the thermal pressure distribution, and (b) is a vector diagram of the infiltration air velocity.

[0047] Figure 2 This is a schematic diagram of the side-mounted segmented circulating air curtain device for cold storage according to the present invention;

[0048] Figure 3 This is a schematic diagram of the air outlet in Example 1;

[0049] Figure 4 This is a schematic diagram of the return air vent in Example 1;

[0050] Figure 5 A detailed schematic diagram of the wind turbine control unit;

[0051] Figure 6 The velocity contour maps of the air curtain outflow at different heights are shown; among them, (a) to (c) are the velocity contour maps of the air curtain outflow at heights of 0.5 m, 1.5 m, and 2.5 m, respectively.

[0052] Attached reference numerals: 1-Outlet duct section, 2-Return duct section, 3-Return circulation duct section, 4-Return air filter device, 5-Outlet, 6-Guide vane, 7-Return air outlet, 8-Outlet section fan control unit. Detailed Implementation

[0053] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0054] Example 1

[0055] The characteristic of cold storage is the significant temperature difference between the indoor and outdoor areas, creating substantial thermal pressure at the cold storage door, which drives the formation of infiltration air through the door. Based on the theory of natural ventilation under thermal pressure, the expression for the thermal pressure difference between the inside and outside of the cold storage is:

[0056] ΔP=P c -P w =(P n -ρ c g(hh n ))-(P n -ρ w g(hh n ))=(ρ w -ρ c )g(hh n )

[0057] In the formula, ΔP represents the thermal pressure difference between the inside and outside of the cold storage at a height of h meters, in Pa; P c P wThese represent the indoor and outdoor pressures at a height of h meters, in Pa; h n The height of the neutral plane, i.e., the position where indoor and outdoor pressures are equal, is indicated in meters (m); P n The pressure (Pa) represents the indoor and outdoor pressures at the height of the neutralization surface. This is because the density of warm outdoor air is less than the density (ρ) of the cold air inside the cold storage. w <ρ c When h = h n At this point, ΔP = 0, meaning that there is usually a neutralization surface at the middle height of the building entrance where the indoor and outdoor pressures are equal, and the infiltration velocity near the neutralization surface is close to zero; above the neutralization surface, h > h. n ΔP < 0, therefore warm air flows from outside into the cold storage room; below the neutral plane height h < h n Since ΔP > 0, cold air flows from inside the cold storage room to the outside. For example... Figure 1 As shown, the thermal pressure intensity and infiltration air volume exhibit a clear gradient characteristic along the height direction: the farther away from the neutral surface, the greater the thermal pressure intensity and the greater the infiltration air volume.

[0058] To address the aforementioned issues, this embodiment provides a side-mounted segmented circulating air curtain device for cold storage. The outflow parameters of the air curtain are set according to the thermal pressure distribution characteristics at the cold storage door, and a return air inlet and return air duct are provided to achieve air circulation inside the air curtain, thereby blocking heat exchange between the cold storage and the external environment.

[0059] Next, the apparatus of the embodiment will be described in detail.

[0060] like Figure 2 As shown, the side-mounted segmented circulating air curtain device for cold storage in this embodiment includes an air outlet section 1, an air outlet 5, a return air inlet 7, a return air section 2, and a return air circulation section 3. The air outlet 5 is a multi-segment air outlet installed vertically on one side of the cold storage door frame, and the return air inlet 7 is located on the opposite side of the cold storage door frame. The airflow blown out of the air outlet section 1 through the air outlet 3 passes through the cold storage door and enters the return air inlet 7. After converging through the return air section 2, it returns to the air outlet section 1 through the return air circulation section 3, forming air circulation inside the air curtain. The airflow volume and airflow angle of each air outlet section are independently controlled according to the thermal pressure distribution characteristics at the cold storage door.

[0061] In this embodiment, the segmented air outlets satisfy the following conditions: the width of each segmented air outlet remains unchanged, and the air outlet speed of each segmented air outlet is changed to control the air volume of each segmented air outlet.

[0062] A variable frequency fan controller, a speed-regulating motor, and a variable frequency fan are installed in the segmented air outlet 5; the variable frequency fan controller is connected to the speed-regulating motor to control the flow rate of the variable frequency fan, forming an independent air outlet section fan control unit 8, such as... Figure 5As shown, the number of fan control units in the air outlet section is the same as the number of the 5 air outlet sections and corresponds one-to-one, so as to independently control the air volume of each air outlet section.

[0063] like Figure 3 As shown, air outlet 5 can be a slotted air outlet, divided into n segments (n≥2) in the height direction. The air volume and outlet angle of each segment can be controlled independently. The width of the return air outlet is greater than or equal to the width of the air outlet.

[0064] Furthermore, each segmented air outlet can be equipped with a temperature control module triggered by a temperature difference threshold to control the outlet temperature of each segment, satisfying the following conditions: the outlet temperature of each segment above the neutralization surface is lower than the outlet temperature of each segment below the neutralization surface; and the outlet temperature of each segment does not increase from the neutralization surface towards the highest segment, nor decrease from the neutralization surface towards the lowest segment. Here, the temperature difference is the difference between the temperature inside the cold storage and the ambient temperature outside the cold storage. In this embodiment, each segmented air outlet is independently equipped with a temperature control module. The temperature control module can be a semiconductor refrigeration chip or any other existing gas refrigeration device, which will not be elaborated here. The number of temperature control modules in this embodiment can be freely set according to actual conditions. For example, each segmented air outlet may be independently equipped with a temperature control module, one temperature control module may be installed above and below the neutralization surface, or only one temperature control module may be installed above the neutralization surface, etc.

[0065] In this embodiment, each air outlet 5 is provided with a guide vane 6, the angle of which is adjustable and fixed; the guide vane controller is the same as and corresponds one-to-one with the guide vane 6 of the air outlet 5; the angle between the guide vane 6 and the plane where the cold storage door is located is defined as the air outlet angle, and the air outlet angle of each air outlet is adjusted by the guide vane controller.

[0066] Furthermore, baffles are installed on both sides of the return air vent 6 along the height direction to prevent the air curtain jet from overflowing into the cold storage space after reaching the return air vent without being collected.

[0067] Furthermore, in this embodiment, the return air vent can be a segmented return air vent, such as... Figure 4 As shown, each section corresponds to a segmented air outlet. The baffle is an adjustable arc-shaped baffle, and the direction of the arc-shaped baffle is consistent with the air outlet angle of the corresponding segment, that is, it is simultaneously biased towards the inside of the cold storage or simultaneously biased towards the outside of the cold storage.

[0068] Furthermore, the return air inlet 7 is connected to the outlet air section 1 through the return air circulation pipe section 3, and a return air filter device 4 is installed on the return air circulation pipe section 3, which further improves the safe and stable operation of the circulating air curtain device.

[0069] In this embodiment, the air outlet is a segmented rectangular air outlet, and the return air outlet is a rectangular return air outlet. The width of the return air outlet is not less than the width of the air outlet.

[0070] The methods for determining the air volume and angle of each air outlet section include:

[0071] 1) Obtain the height H and width W of the cold storage door, the width B of the air curtain outlet, and the temperature T inside the cold storage. c and the ambient temperature T w ;

[0072] 2) Based on the relationship between the thermal pressure on both sides of the cold storage door and the air curtain jet flow rate, the calculation expression for the total air curtain volume Q was derived through experimental simulation:

[0073]

[0074] In the formula, γ, ω, β, λ, and δ are the fitting parameters, respectively;

[0075] In this embodiment, considering that the thermal pressure on both sides of the cold storage door is determined by the cold storage temperature, the ambient temperature and the size of the cold storage door (including height and width), and that the air volume required for the jet is affected by the width of the air curtain outlet, in order to ensure that the jet flow rate is sufficient to resist the influence of the thermal pressure on both sides of the cold storage door, the total air volume of the air curtain is determined by the above five parameters.

[0076] Based on the above experimental simulation fitting formula, for different cold storage temperatures, ambient temperatures, cold storage door dimensions (including height and width), and for a given air curtain outlet width, the total air volume of the air curtain can be calculated, thereby guiding the selection of air curtain fan equipment.

[0077] Instead of directly using the temperature difference, the ratio of the temperature difference between the inside and outside of the cold storage is used as the exponential base of the temperature term in the fitting expression, which further improves the accuracy of the total air volume fitting prediction of the air curtain.

[0078] 3) Based on the thermal pressure that each air outlet section needs to withstand and the center height of each air outlet section, calculate the ratio of the thermal pressure that each air outlet section needs to withstand to allocate the air volume of each air outlet section. Then, based on the air volume of each air outlet section, determine the air velocity of each air outlet section, specifically:

[0079] According to the thermal pressure ΔP1 corresponding to the center height h1 of the segmented air outlet, ΔP1 = (ρ w -ρ c )g(h1-H n The center height h of the segmented air outlet n Corresponding hot pressure: ΔP n =(ρ w -ρ c )g(h n -H nThe center height h1 of the segmented air outlet and the center height h of the segmented air outlet can be determined. n The corresponding hot-press ratio is Among them, H n ρ is the height of the neutral surface. w ρ c These represent the ambient air density and the air density inside the cold storage, respectively; g is the gravitational acceleration at the Earth's surface.

[0080] According to the ratio of thermal pressure, which is equal to the ratio of air curtain flow rate. Obtain the center height h1 of the segmented air outlet and the center height h of the segment. n The formula for calculating the relationship between flow rate and bandwidth: Among them, u1, u n These are the center heights of the segmented air outlets, h1 and h, respectively. n Corresponding air outlet speeds; B1, B n These are the segment center height h1 and segment center height h, respectively. n The corresponding air outlet width; Q1 represents the center height h1 and center height h of the segmented air outlets, respectively. n Corresponding air volume;

[0081] 4) Based on the magnitude and direction of the thermal pressure corresponding to each air outlet, determine the magnitude and direction of the air outlet angle for each air outlet. The air outlet angle direction satisfies the following: symmetrically opposite along the middle height of the cold storage door, with the air outlets above the neutral plane facing outwards from the cold storage, and the air outlets below the neutral plane facing inwards from the cold storage. The air outlet angle magnitude satisfies the following: symmetrically equal along the middle height of the cold storage door, with the middle section having the smallest air outlet angle and the highest and lowest sections having the largest air outlet angles. The air outlet angles for each air outlet are then allocated accordingly.

[0082] If the number of segments n is odd The segmented air curtain is set to 0°, meaning the airflow is directed directly towards the return air vent. Based on the center height of each segment's air outlet, the outlet angles for the highest and lowest segments are set to +α1 and -α, respectively. n (Define that the air curtain outlet facing outwards from the cold storage is positive, and facing inwards from the cold storage is negative), and then allocate the outlet angles of each section of the air curtain (α1, α2, ..., α...). n ).

[0083] Furthermore, the air outlet angle distribution from the middle section to the highest section or from the middle section to the lowest section can be arithmetically distributed, or the speed increase can be set from high to low.

[0084] Next, this embodiment uses computer simulation (CFD) to illustrate the blocking effect of the side-mounted segmented circulating air curtain on the cold storage permeation load.

[0085] Parameter settings: Cold storage temperature is -18℃, ambient temperature is 24℃. Cold storage dimensions are 10m × 10m × 4m (length × width × height), and the cold storage door dimensions are 2.4m × 3.0m (width × height). The width of the air curtain device's outlet and return air inlet is set to 0.05m, and its height is the same as the cold storage door.

[0086] Based on the calculation formula proposed in this invention, the optimal total airflow for the air curtain is determined to be 2.4 m³. 3 / s. During calculation, the airflow volume of each outlet section is first set to be equal and the outlet angle to be 0°. At this point, the heat barrier efficiency of the air curtain device is 75.9%. Taking a three-section air curtain as an example, setting the outlet airflow volume and outlet angle segmented along the height can improve the heat barrier efficiency by approximately 11.4%. The highest efficiencies achieved by two-section, three-section, and five-section outlet air curtains are 83.6%, 87.3%, and 90.3%, respectively. The barrier efficiency achievable by the air curtain remains stable despite changes in temperature difference between the two sides. Figure 6 The velocity contour maps of the air curtain outflow at different heights are shown, where (a) to (c) are velocity contour maps of the air curtain outflow at heights of 0.5 m, 1.5 m, and 2.5 m, respectively.

[0087] In this embodiment, when the number of air curtain segments n approaches infinity, the air outlet velocity of each segment changes continuously along the height direction, which can be approximately written as... A and C are constant terms. The air outlet is equipped with a progressive and uniform speed adjustment device, and the air outlet speed is gradually set from top to bottom along the height direction.

[0088] Furthermore, in this embodiment, the composition of the gas blown out from the air outlet can be adjusted in stages within the air outlet duct section. Depending on the actual needs of the cold storage, some special inert safety gases can be used, and a portion of the inert safety gas can be introduced in stages. Specifically, for controlled atmosphere storage of fruits, the air curtain can use air outlets with a set content of gases such as carbon dioxide for isolation and preservation.

[0089] Example 2

[0090] In this embodiment, the air velocity of each segmented air outlet 5 remains constant, and the width of each segmented air outlet 5 is changed to control the air volume of each segmented air outlet 5.

[0091] The air outlet 5 is equipped with a variable frequency fan controller, a speed regulating motor and a variable frequency fan. The variable frequency fan controller is connected to the speed regulating motor and is used to control the flow rate of the variable frequency fan. The air outlet is also equipped with an air rectification module to ensure that the speed of each segment of the air outlet is evenly distributed.

[0092] In this embodiment, the number of air outlet fan control units does not need to correspond to the number of air outlet segments.

[0093] The process of setting the air volume and air outlet angle for each section of the air outlet includes:

[0094] 1) Obtain the height H and width W of the cold storage door, the width B of the air curtain outlet, and the temperature T inside the cold storage. c and the ambient temperature T w ;

[0095] 2) Based on the relationship between the thermal pressure on both sides of the cold storage door and the air curtain jet flow rate, the calculation expression for the total air curtain volume Q was derived through experimental simulation:

[0096]

[0097] In the formula, γ, ω, β, λ, and δ are the fitting parameters, respectively;

[0098] 3) Based on the thermal pressure that each air outlet section needs to withstand and the center height of each air outlet section, calculate the ratio of the thermal pressure that each air outlet section needs to withstand to allocate the air volume of each air outlet section. Then, based on the air volume of each air outlet section, determine the width of each air outlet section, specifically:

[0099] According to the thermal pressure ΔP1 corresponding to the center height h1 of the segmented air outlet, ΔP1 = (ρ w -ρ c )g(h1-H n The center height h of the segmented air outlet n Corresponding hot pressure: ΔP n =(ρ w -ρ c )g(h n -H n The center height h1 of the segmented air outlet and the center height h of the segmented air outlet can be determined. n The corresponding hot-press ratio is Among them, H n ρ is the height of the neutral surface. w ρ c These represent the air density inside the cold storage and the air density in the external environment, respectively; g is the gravitational acceleration at the Earth's surface.

[0100] According to the ratio of thermal pressure, which is equal to the ratio of air curtain flow rate. Obtain the center height h1 of the segmented air outlet and the center height h of the segment. n The formula for calculating the relationship between flow rate and bandwidth: Among them, u1, u n These are the center heights of the segmented air outlets, h1 and h, respectively. n Corresponding air outlet speeds; B1, B n These are the segment center height h1 and segment center height h, respectively. nThe corresponding air outlet width; Q1 represents the center height h1 and center height h of the segmented air outlets, respectively. n Corresponding air volume;

[0101] 4) Based on the magnitude and direction of the thermal pressure corresponding to each air outlet, determine the magnitude and direction of the air outlet angle for each air outlet. The air outlet angle direction satisfies the following: symmetrically opposite along the middle height of the cold storage door, with the air outlets above the neutral plane facing outwards from the cold storage, and the air outlets below the neutral plane facing inwards from the cold storage. The air outlet angle magnitude satisfies the following: symmetrically equal along the middle height of the cold storage door, with the middle section having the smallest air outlet angle and the highest and lowest sections having the largest air outlet angles. The air outlet angles for each air outlet are then allocated accordingly.

[0102] If the number of segments n is odd The segmented air curtain is set to 0°, meaning the airflow is directed directly towards the return air vent. Based on the center height of each segment's air outlet, the outlet angles for the highest and lowest segments are set to +α1 and -α, respectively. n (Define that the air curtain outlet facing outwards from the cold storage is positive, and facing inwards from the cold storage is negative), and then allocate the outlet angles of each section (α1, α2, ..., α...). n ).

[0103] Furthermore, the segmented air outlets can be equipped with temperature control modules triggered by temperature difference thresholds to control the outlet temperature of each segment, satisfying the following conditions: the outlet temperature of each segment above the neutralization surface is lower than the outlet temperature of each segment below the neutralization surface; and the outlet temperature of each segment does not increase from the neutralization surface towards the highest segment, nor decrease from the neutralization surface towards the lowest segment. Here, the temperature difference is the difference between the temperature inside the cold storage and the ambient temperature outside the cold storage. In this embodiment, the number of temperature control modules can be freely set according to actual conditions. For example, each segmented air outlet can have an independent temperature control module, one module can be installed above and below the neutralization surface, or only one temperature control device can be installed above the neutralization surface, etc.

[0104] In this embodiment, the segmented air outlet is a segmented rectangular air outlet, with each segmented rectangular air outlet having the same height but different widths.

[0105] As the number of air curtain segments n approaches infinity, the width of the air outlet of each segment changes continuously along the height direction, which can be approximately written as b = f(hH). n )=B(hH n )+C, where B and C are constant terms. In this case, the air outlet can be set up as an integrated air outlet, which is shaped like an hourglass.

[0106] The other settings in this embodiment are the same as in Embodiment 1.

[0107] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A side-mounted segmented circulating air curtain device for cold storage, used to block heat exchange between the cold storage and the external environment, the device comprising an air outlet section, an air outlet, a return air outlet, a return air section, and a return air circulation section, characterized in that, The air outlet is a segmented air outlet installed vertically on one side of the cold storage door frame, and the return air outlet is located on the opposite side of the cold storage door frame; The airflow blown out of the air outlet of the air outlet section passes through the cold storage door and enters the return air inlet. After converging through the return air section, it returns to the air outlet section through the return air circulation section, forming air circulation inside the air curtain. The air volume and air angle of the segmented air outlets are set according to the thermal pressure distribution characteristics at the cold storage door, and the air outlets of each segment are independently controlled. The segmented air outlets meet the following requirements: the width of each segmented air outlet remains constant, and the air velocity of each segmented air outlet is changed to control the air volume of the segmented air outlet; or the air velocity of each segmented air outlet remains constant, and the width of each segmented air outlet is changed to control the air volume of the segmented air outlet. The process of setting the air volume and air outlet angle of segmented air outlets includes: 1) Obtain the height of the cold storage door With width Width of the air curtain outlet Temperature inside the cold storage and the ambient temperature ; 2) Based on the relationship between the thermal pressure on both sides of the cold storage door and the air curtain jet flow rate, the total air volume of the air curtain was calculated through experimental simulation. The calculation expression: In the formula, These are the fitting parameters; 3) Based on the thermal pressure that the segmented air outlets need to withstand and the center height of the segmented air outlets, calculate the ratio of the thermal pressure that each segmented air outlet needs to withstand in order to allocate the air volume of each segmented air outlet. Then, based on the air volume of each segmented air outlet, determine the air velocity of each segmented air outlet or the width of each segmented air outlet. 4) Based on the magnitude and direction of the thermal pressure corresponding to the segmented air outlets, determine the magnitude and direction of the air outlet angle for each segment. The air outlet angle direction satisfies the following: symmetrically opposite along the middle height of the cold storage door, with the air outlets above the neutral plane facing outwards from the cold storage, and the air outlets below the neutral plane facing inwards from the cold storage. The air outlet angle magnitude satisfies the following: symmetrically equal along the middle height of the cold storage door, with the middle segment having the smallest air outlet angle and the highest and lowest segments having the largest air outlet angles. The air outlet angles for each segment are then allocated accordingly.

2. The side-mounted segmented circulating air curtain device for cold storage according to claim 1, characterized in that, The width of each segment air outlet remains constant, while the air outlet speed of each segment air outlet is changed to control the air volume of the segment air outlet. The segmented air outlet is equipped with a variable frequency fan controller, a speed-regulating motor, and a variable frequency fan; the variable frequency fan controller is connected to the speed-regulating motor and is used to control the flow rate of the variable frequency fan, forming an independent air outlet segment fan control unit; the number of air outlet segment fan control units is the same as the number of air outlet segments and corresponds one-to-one, so as to independently control the air volume of the segmented air outlet.

3. A side-mounted segmented circulating air curtain device for cold storage according to claim 1, characterized in that, The air velocity of each segment air outlet remains constant, while the width of each segment air outlet is changed to control the air volume of the segment air outlet. The air outlet is equipped with a variable frequency fan controller, a speed-regulating motor, and a variable frequency fan. The variable frequency fan controller is connected to the speed-regulating motor and is used to control the flow rate of the variable frequency fan. The air outlet is also equipped with an air rectification module to ensure that the speed of each segment of the air outlet is evenly distributed.

4. A side-mounted segmented circulating air curtain device for cold storage according to claim 1, characterized in that, The segmented air outlets are equipped with a temperature control module triggered by a temperature difference threshold, which is used to control the air outlet temperature of each segment to meet the following conditions: the air outlet temperature of each segment above the neutral plane is lower than the air outlet temperature of each segment below the neutral plane, and the air outlet temperature of each segment is not increased from the neutral plane towards the highest segment, and the air outlet temperature of each segment is not decreased from the neutral plane towards the lowest segment.

5. A side-mounted segmented circulating air curtain device for cold storage according to claim 1, characterized in that, Each segmented air outlet is equipped with an adjustable and fixed guide vane, and a guide vane controller that corresponds to each segmented air outlet guide vane. The air outlet angle of the segmented air outlet is adjusted by the guide vane controller. The air outlet angle is the angle between the guide vane and the plane where the cold storage door is located.

6. A side-mounted segmented circulating air curtain device for cold storage according to claim 1, characterized in that, The return air inlet is equipped with baffles along the height direction on both sides to prevent the air curtain jet from overflowing into the cold storage space after reaching the return air inlet without being collected.

7. A side-mounted segmented circulating air curtain device for cold storage according to claim 6, characterized in that, The return air inlet is a segmented return air inlet, corresponding one-to-one with the segmented air outlet; the guide baffle is an adjustable arc-shaped guide baffle, and the deflection direction of the arc-shaped guide baffle is consistent with the air outlet angle direction of the corresponding segment, that is, both deflected towards the inside of the cold storage or both deflected towards the outside of the cold storage.

8. A side-mounted segmented circulating air curtain device for cold storage according to claim 1, characterized in that, A return air filter is installed in the return air circulation pipe section.

9. A side-mounted segmented circulating air curtain device for cold storage according to claim 1, characterized in that, In step 3), based on the magnitude of the thermal pressure that the segmented air outlets need to withstand and the center height of the segmented air outlets, the ratio of the thermal pressure that each segment of the air outlet needs to withstand is calculated to allocate the airflow of each segment of the air outlet. Then, based on the airflow of each segment of the air outlet, the airflow velocity of each segment of the air outlet or the width of each segment of the air outlet is determined, specifically: Based on the center height of the segmented air outlets Corresponding hot pressing Center height of segmented air outlets Corresponding hot pressing: The center height of the segmented air outlets can be determined. Height of the segmented air outlet center The corresponding hot-press ratio is ;in, The height of the neutral surface. These are the ambient air density and the air density inside the cold storage, respectively. This is the gravitational acceleration at the Earth's surface; According to the ratio of thermal pressure, which is equal to the ratio of air curtain flow rate. The center height of the segmented air outlets is obtained. and segment center height The formula for calculating the relationship between flow rate and bandwidth: ;in, The center height of the segmented air outlets are respectively Center height of segmented air outlets Corresponding air outlet speed; These are the segment center heights. Segment center height Corresponding air outlet width; The center height of the segmented air outlets are respectively Height of the segmented air outlet center The corresponding air volume.

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