An air heat exchange device suitable for large temperature difference or large enthalpy difference scene

Abstract

The utility model discloses a kind of air heat exchange devices suitable for under the scene of big temperature difference or big enthalpy difference, it is related to fresh air handling system technical field;It is to realize high-efficiency energy recovery under the scene of big temperature difference or big enthalpy difference, and the following technical scheme is proposed: including heat exchanger shell and the double-layer central shaft pipeline of being arranged in heat exchanger shell center, double-layer central shaft pipeline includes concentric but mutually isolated inner layer pipeline and outer layer pipeline;Spiral total heat heat exchange plate and spiral sensible heat heat exchange plate are equipped in heat exchanger shell, and sensible heat heat exchange passage formed by sensible heat heat exchange plate and total heat heat exchange passage formed by total heat heat exchange plate are communicated, to form the first fluid channel and second fluid channel of each other counter-current in heat exchanger shell interior.The utility model achieves threefold target of improving heat recovery efficiency, improving equipment integration, improving equipment reliability synchronously, fills the blank of stable air heat recovery system under the scene of big temperature difference, big enthalpy difference application.

Description

Technical Field

[0001] This utility model relates to the technical field of fresh air treatment systems, specifically to an air heat exchange device suitable for scenarios with large temperature differences or large enthalpy differences. Background Technology

[0002] Modern high-performance cold storage facilities are designed with extremely high airtightness to maintain a low-temperature environment and reduce energy consumption. However, this design prevents natural air convection between the inside and outside of the storage facility, resulting in extremely poor indoor air quality.

[0003] In a confined environment, operators who remain there for extended periods consume oxygen and exhale carbon dioxide, potentially causing a continuous decrease in oxygen concentration within the cold storage. In severe cases, this poses a significant safety risk of operators suffocating due to oxygen deprivation. Therefore, from an occupational safety and health perspective, introducing fresh air into the cold storage work area is a necessary measure.

[0004] Currently, to address the aforementioned safety issues, the industry has experimented with different methods for introducing fresh air, but all of them have significant drawbacks: Directly introducing outdoor air into the cold storage facility solves the oxygen deficiency problem, but the untreated, hot, and humid outdoor air directly and violently disrupts the stable low-temperature environment inside, causing significant temperature fluctuations. More importantly, it introduces an additional moisture load, forcing the refrigeration system to defrost more frequently, leading to a sharp increase in system energy consumption and a decrease in operating efficiency.

[0005] Using a total heat exchanger allows for the simultaneous introduction of fresh air and exhaust of waste air from the cold storage facility, while also performing heat and moisture exchange. This method effectively reduces temperature and humidity loads and energy consumption. However, in the hot and humid summer, when outdoor fresh air meets low-temperature exhaust air inside the total heat exchanger, the surface temperature of the heat exchange core is easily lower than the dew point temperature of the fresh air, leading to severe condensation or even frost. Condensate can clog the flow channels, breed mold, and over time corrode and damage the expensive total heat exchange core, making it unreliable under extreme operating conditions such as cold storage.

[0006] Sensible heat exchangers only perform heat exchange and not moisture exchange, thus avoiding condensation problems. However, their disadvantages are also prominent: the heat exchange efficiency is usually lower than that of total heat exchangers, and they cannot recover the latent heat in the exhaust air, resulting in insufficient energy recovery, limited energy-saving effects, and failure to fundamentally solve the problem of excessive energy consumption.

[0007] In summary, there is an urgent need in this field for a fresh air exchange solution suitable for cold storage environments, which needs to simultaneously meet the following three conflicting requirements: 1. Ensure safe ventilation; 2. Prevent condensation damage to the total heat exchanger; 3. Maintain high energy recovery efficiency to control energy consumption. Existing single technological approaches cannot simultaneously solve these three problems, thus creating a technological bottleneck. Utility Model Content

[0008] This invention provides an air heat exchange device suitable for scenarios with large temperature differences or large enthalpy differences. The purpose is to enable the cold storage fresh air system to achieve safe ventilation and high-efficiency energy recovery while avoiding condensation on the heat exchanger.

[0009] The technical solution of this utility model to solve the above-mentioned technical problems is as follows: An air heat exchange device suitable for scenarios with large temperature or enthalpy differences includes a heat exchanger shell and a double-layer central axial pipe disposed on the top of the heat exchanger shell. The double-layer central axial pipe includes an inner pipe and an outer pipe that are concentric but isolated from each other. The heat exchanger shell is provided with a spiral total heat exchange plate and a spiral sensible heat exchange plate. The sensible heat exchange channel formed by the sensible heat exchange plate is connected to the total heat exchange channel formed by the total heat exchange plate, thereby forming a first fluid channel and a second fluid channel that flow in opposite directions inside the heat exchanger shell. The inner pipe has an inlet at the top and an outlet on the side. The first fluid channel includes an outdoor fresh air inlet, the outdoor fresh air inlet outlet is connected to the inlet of the first total heat exchange channel, the outlet of the first sensible heat exchange channel is connected to the inlet of the first sensible heat exchange channel, the outlet of the first sensible heat exchange channel is connected to the outer pipe, and the outer pipe is connected to the outdoor fresh air outlet on the side of the double-layer central axis pipe. The second fluid channel includes an indoor exhaust inlet, an indoor exhaust inlet outlet connected to an inner layer pipe inlet, an inner layer pipe outlet connected to a second sensible heat exchange channel inlet, a second sensible heat exchange channel outlet connected to a second total heat exchange channel inlet, and a second total heat exchange channel outlet connected to an indoor exhaust outlet on the side of the heat exchanger shell.

[0010] Furthermore, the outer surfaces of the total heat exchange plate and the sensible heat exchange plate are provided with an insulation layer.

[0011] Furthermore, the total heat exchange plate is fitted over the sensible heat exchange plate.

[0012] Furthermore, condensate baffles are installed at the connection between the total heat exchange plate and the sensible heat exchange plate, as well as at the connection between the sensible heat exchange plate and the double-layer central axial pipe.

[0013] Furthermore, a condensate drain outlet is provided at the bottom of the heat exchanger shell near the double-layer central axis pipe in the fresh air sensible heat recovery channel, and the bottom of the heat exchanger shell is sloped towards the condensate drain outlet.

[0014] This utility model has the following beneficial effects: This invention fundamentally solves the core problem of balancing condensation at low temperatures and high efficiency in heat exchangers. Outdoor fresh air first flows through the outer total heat exchange plate, where it exchanges heat with the indoor low-temperature, low-humidity exhaust air, which has already been heated below the outdoor dew point by the sensible heat exchanger and is about to be discharged. This process achieves initial cooling and dehumidification. The pre-cooled and initially dehumidified fresh air then enters the inner sensible heat exchange plate, where it exchanges sensible heat with the indoor exhaust air and condenses, which is discharged from the heat exchanger through the condensate drain. By heating the indoor air to above the outdoor dew point through sensible heat exchange before entering the total heat exchange section, the problem of condensation in the total heat exchanger is effectively avoided.

[0015] Secondly, it maximizes energy recovery efficiency. Fresh air and exhaust air pass sequentially through the sensible heat and total heat exchange zones in a completely counter-current manner, forming two deep heat exchange processes. This not only fully recovers the sensible heat in the exhaust air but also dehumidifies and pre-cools the fresh air through the outer total heat exchange layer, resulting in a comprehensive heat exchange efficiency far exceeding that of a single sensible heat exchanger. The counter-current arrangement further enhances heat transfer performance, making energy recovery more thorough and significantly reducing the cooling load and defrosting frequency caused by the introduction of fresh air, resulting in outstanding energy-saving effects.

[0016] Furthermore, the structure is ingeniously designed and compactly integrated. The spiral double-layer flow channel structure ensures sufficient heat exchange area and counter-current fluid flow while reducing the equipment size. The double-layer central axis pipe enables efficient fluid guidance and separation. The insulation layer reduces cold loss and isolates the two heat exchange processes (sensible heat and latent heat), while the baffle plate and drain outlet constitute a complete condensate protection and drainage mechanism, enhancing the adaptability and functional integrity of the device. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the air heat exchange device of this utility model applicable to scenarios with large temperature difference or large enthalpy difference; Figure 2 This is a side sectional view of the air heat exchange device of this utility model applicable to scenarios with large temperature difference or large enthalpy difference; Figure 3 This is a bottom cross-sectional view of the air heat exchange device of this utility model applicable to scenarios with large temperature difference or large enthalpy difference; Figure 4 This is a schematic diagram of a double-layered central axial pipe structure.

[0018] Figures 1 to 4The reference numerals in the attached drawings represent: 1-heat exchanger shell, 2-double-layer central axial pipe, 21-inner pipe, 211-inner pipe inlet, 212-inner pipe outlet, 22-outer pipe, 3-condensate drain, 4-condensate baffle, 5-insulation layer, 6-outdoor fresh air inlet, 7-outdoor fresh air outlet, 8-indoor exhaust air inlet, 9-indoor exhaust air outlet, 11-sensible heat exchange plate, 111-sensible heat exchange channel, 1111-first sensible heat exchange channel, 1112-second sensible heat exchange channel, 12-total heat exchange plate, 121-total heat exchange channel, 1211-first total heat exchange channel, 1212-second total heat exchange channel. Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments: Please refer to Figure 1-4 This embodiment describes in detail an air heat exchange device suitable for scenarios with large temperature differences or large enthalpy differences, including a heat exchanger shell 1 and a double-layer central axis pipe 2 disposed on the top of the heat exchanger shell 1. The double-layer central axis pipe 2 includes an inner pipe 21 and an outer pipe 22 that are concentric but isolated from each other. The heat exchanger shell 1 is provided with a spiral sensible heat exchange plate 11 and a spiral total heat exchange plate 12. The total heat exchange channel 121 formed by the total heat exchange plate 12 is connected to the sensible heat exchange channel 111 formed by the sensible heat exchange plate 11, thereby forming a first fluid channel and a second fluid channel that flow in opposite directions inside the heat exchanger shell 1. The inner pipe 21 is provided with an inner pipe inlet 211 at the top and an inner pipe outlet 212 on the side of the inner pipe 21. The first fluid channel includes an outdoor fresh air inlet 6, the outlet end of which is connected to the inlet end of the first total heat exchange channel 1211, the outlet end of the first total heat exchange channel 1211 is connected to the inlet end of the first sensible heat exchange channel 1111, the outlet end of the first sensible heat exchange channel 1111 is connected to the outer pipe 22, and the outer pipe 22 is connected to the outdoor fresh air outlet 7 on the side of the double-layer central axis pipe 2. The second fluid channel includes an indoor exhaust inlet 8, the outlet of which is connected to an inner layer pipe inlet 211. The inner layer pipe inlet 211 is connected to an inner layer pipe outlet 212 via an inner layer pipe 21. The inner layer pipe outlet 212 is connected to the inlet of the second sensible heat exchange channel 1112. The outlet of the second sensible heat exchange channel 1112 is connected to the inlet of the second total heat exchange channel 1212. The outlet of the second total heat exchange channel 1212 is connected to the indoor exhaust outlet 9 on the side of the heat exchanger shell 1.

[0020] The heat exchanger shell 1 is cylindrical, but can also be designed as a square or other polygonal shape depending on the actual installation requirements. The primary function of the heat exchanger shell 1 is to provide a sealed and structurally stable cavity for all internal heat exchange components, ensuring orderly heat and mass exchange between the two airflow channels within this cavity and preventing interference from the external environment. A double-layer central axial duct 2 is fixedly installed at the top center of the heat exchanger shell 1. This double-layer central axial duct 2 is a key structure for achieving counter-current flow and centralized delivery of the two airflows. It consists of a concentric but isolated inner duct 21 and an outer duct 22. The double-layer central axial duct 2 penetrates the top plate of the heat exchanger shell 1. The inner duct 21 provides a central channel for indoor exhaust air to enter the device, while the outer duct 22 provides an annular channel for treated outdoor fresh air to exit the device, making it the core of achieving a counter-current, compact layout.

[0021] Inside the heat exchanger shell 1, the core heat exchange elements are a spiral sensible heat exchange plate 11 and a spiral total heat exchange plate 12. The total heat exchange plate 12 is a component capable of simultaneously conducting heat (sensible heat) and allowing water vapor to pass through (latent heat), made of a material with sufficient strength, moisture permeability, and corrosion resistance. These materials have numerous micropores on their surface, allowing water vapor molecules to diffuse due to the vapor partial pressure difference on both sides, thus achieving latent heat exchange. The sensible heat exchange plate 11, on the other hand, is a component that can only conduct heat and cannot allow water vapor to pass through. Its surface is smooth and non-porous, possessing good thermal conductivity and moisture resistance. Both are rolled or processed into a spiral structure with hollow channels. This spiral structure can provide a large heat exchange area within a limited space, and the flow channel design guides the airflow to flow smoothly in opposite directions. The total heat exchange plate 12 and the sensible heat exchange plate 11 are connected in series. Specifically, the sensible heat exchange plate 11 is located inside, and the total heat exchange plate 12 is fitted onto the outside, with both arranged coaxially. The outlet end of the sensible heat exchange plate 11 is directly connected to and sealed to the inlet end of the total heat exchange plate 12. Outdoor fresh air first enters the outer total heat exchange plate 12. In summer, the hot and humid fresh air is initially cooled and dehumidified by the exhaust air, which has been heated to above the outdoor dew point temperature, after passing through the total heat exchanger. When the fresh air subsequently enters the inner sensible heat exchange plate 11, it exchanges heat with the low-temperature indoor exhaust air and condenses. The indoor exhaust air is first heated to below the outdoor air dew point by the inner sensible heat exchange plate 11 before entering the outer total heat exchange plate 12, completing the cascade recovery of energy and achieving "dry and wet separation".

[0022] Through the combination of the above components, a first fluid channel and a second fluid channel that flow in opposite directions are formed inside the heat exchanger shell 1. The first fluid channel is the outdoor fresh air passage: outdoor fresh air enters from the outdoor fresh air inlet 6 located at the lower part of the side wall of the heat exchanger shell 1. The outdoor fresh air inlet 6 is an interface connected to an external fresh air duct. Driven by a fan (not shown in the figure), the outdoor fresh air first enters the first total heat exchange channel 1211, flows through the first sensible heat exchange channel 1111 to the outer duct 22, and spirals from the outside to the inside. During this process, the low-temperature dry indoor exhaust air is flowing in the opposite direction on the other side of the total heat exchange plate 12. The outdoor fresh air exchanges total heat with the exhaust air through the wall of the total heat exchange plate 12. At this time, the fresh air transfers a small portion of sensible heat and most of the latent heat (water vapor) to the exhaust air in the 1212 flow channel through the total heat exchange plate. Subsequently, the pre-treated outdoor fresh air flows out from the outlet of the total heat exchange plate 12 and enters the flow channel of the inner spiral sensible heat exchange plate 11 through the connection between the total heat exchange plate 12 and the sensible heat exchange plate 11, spiraling from the outside to the center. At this time, the relatively low temperature and low humidity indoor exhaust air flows in the opposite direction to the outdoor fresh air on the other side of the sensible heat exchange plate 11. Due to the material characteristics of the sensible heat exchange plate 11, only sensible heat exchange occurs between the fresh air and the exhaust air. At this time, the fresh air transfers a large amount of its sensible heat to the exhaust air in the 1112 flow channel while condensing water due to the significant drop in its own temperature. Finally, the treated outdoor fresh air flows out from the outlet of the sensible heat exchange plate 11, enters the outer duct 22 of the double-layer central axis duct 2, and flows out from the outdoor fresh air outlet 7 set on the side wall of the double-layer central axis duct 2, and is sent indoors.

[0023] The second fluid channel is the indoor exhaust air passage: indoor exhaust air enters from the indoor exhaust air inlet 8 located at the top of the double-layer central axis duct 2. The indoor exhaust air inlet 8 is connected to the indoor exhaust duct. Driven by a fan (not shown in the figure), the exhaust air first enters the inner duct inlet 211 of the double-layer central axis duct 2, flows downward and enters the second sensible heat exchange channel 1112 of the spiral total heat exchange plate 12 located inside, and spirals outward from the center through the second total heat exchange channel 1212. Here, it exchanges sensible heat with the fresh air flowing through the sensible heat exchange plate 11 in the first fluid channel, transferring its own cooling capacity to the fresh air and heating itself to above the outdoor air dew point temperature (achieved by adjusting the total heat and sensible heat exchange area according to the indoor and outdoor temperatures set for the applicable location). Subsequently, the exhaust air, with some energy recovered, flows out from the outlet of the sensible heat exchange plate 11 and enters the flow channel of the spiral total heat exchange plate 12, which is fitted externally, through the connection between the total heat exchange plate 12 and the sensible heat exchange plate 11, spiraling outward. The exhaust air undergoes a final total heat exchange with the fresh air flowing through the sensible heat exchange plate 11, further absorbing the heat of the fresh air to increase its own temperature, while simultaneously absorbing a large amount of water vapor from the fresh air through the total heat exchange material. Finally, the low-temperature dry exhaust air, with fully recovered energy, flows out from the outlet of the total heat exchange plate 12 and is discharged to the outside through the indoor exhaust outlet 9 located on the upper side wall of the heat exchanger shell 1. The design of these two fluid channels achieves true counter-current heat exchange, maximizing the heat and mass exchange throughout the entire heat exchange process, thereby achieving extremely high heat exchange efficiency.

[0024] Furthermore, an insulation layer 5 is provided on the outer surface of the sensible heat exchange plate 11 and the total heat exchange plate 12. To further improve the performance of the device in low-temperature environments, prevent condensation, and fully isolate the total heat and sensible heat exchange processes, an insulation layer 5 is provided on the outer surface of the total heat exchange plate 12 and the sensible heat exchange plate 11. This insulation layer 5 is typically made of a material with low thermal conductivity, and its thickness can be selected between 10mm and 50mm depending on the application scenario. The insulation layer 5 can be tightly attached to the outer surface of the heat exchange plate by pasting, wrapping, or on-site foaming. Its main functions are twofold: first, to prevent the heat exchange process from being affected by the outdoor environment; and second, to isolate the total heat exchange process from the sensible heat exchange process. Without the insulation layer, the heat exchange effect cannot be maximized, and condensation may occur during the total heat exchange stage, damaging the heat exchange material.

[0025] Furthermore, condensate baffles 4 are installed at the connection points between the sensible heat exchange plate 11 and the total heat exchange plate 12, as well as at the connection points between the sensible heat exchange plate 11 and the double-layer central axial pipe 2. Condensate baffles 4 are installed at critical connection points. Specifically, there are two locations where they must be installed: the first location is at the connection point between the sensible heat exchange plate 11 and the total heat exchange plate 12. Since this is the junction of two heat exchange plates of different materials and functions, there may be slight gaps or structural abrupt changes, making it a location where condensate can easily accumulate and cause bypass leaks. The condensate baffle 4 installed here is typically an annular component with an upward-curved edge. It effectively collects condensate that may drip from the upper sensible heat exchange plate 11 and guides it to the bottom of the shell, while preventing water from flowing into areas it should not contact or directly into the flow channels of the total heat exchange plate 12. The second location is at the connection point between the sensible heat exchange plate 11 and the double-layer central axial pipe 2. The fresh air reaches its lowest temperature after passing through the sensible heat exchanger 11, making this connection point a high-risk area for condensation. The condensate baffle 4 installed here is also a ring-shaped structure. It ensures that the condensate formed here is effectively trapped and guided to the side wall or bottom of the casing, preventing condensate from being carried by the airflow into the relatively dry fresh air duct leading to the room, causing secondary pollution and duct corrosion. The condensate baffle 4 is fixed by snap-fitting, adhesive bonding, or mechanical clamping.

[0026] Furthermore, a condensate drain outlet 3 is provided at the bottom of the heat exchanger shell 1. To effectively and promptly drain the condensate generated during the entire heat recovery process due to low-temperature surface condensation at the bottom of the heat exchanger shell 1, a condensate drain outlet 3 is specifically designed. The condensate drain outlet 3 is typically a pipe fitting with internal threads or a quick-connect interface, welded or sealed and tightened at the lowest point of the shell bottom. Without this structure or if its location is improper, condensate will accumulate at the bottom of the shell, potentially freezing and expanding, damaging the equipment, or breeding bacteria, affecting air quality, and even being drawn back into the heat exchange core due to excessive water level, severely impacting equipment performance and lifespan. In practical applications, a drain pipe is connected to the condensate drain outlet 3 to guide the condensate to a suitable drainage system. All collected condensate eventually converges at the bottom of the heat exchanger shell 1 and is smoothly discharged from the system through the aforementioned condensate drain outlet 3. The diameter of the condensate drain outlet 3 is calculated based on the processing air volume and air conditions to ensure smooth drainage even at maximum condensate volume; typically, the inner diameter is not less than 10 mm. To ensure smooth drainage while preventing air leakage, the condensate drain outlet 3 is usually connected to a small water tank with a liquid level control function. When the liquid level is higher than the set value, the water valve is opened to drain the condensate. When the liquid level is lower than the set value, the water valve is closed to prevent fresh air from leaking out of the condensate drain outlet 3 after the water is drained.

[0027] Although embodiments of the present 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 present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An air heat exchange device suitable for scenarios with large temperature differences or large enthalpy differences, characterized in that, The device includes a heat exchanger shell (1) and a double-layer central axial pipe (2) disposed at the center of the heat exchanger shell (1). The double-layer central axial pipe (2) includes an inner pipe (21) and an outer pipe (22) that are concentric but isolated from each other. The heat exchanger shell (1) is provided with a spiral sensible heat exchange plate (11) and a spiral total heat exchange plate (12). The total heat exchange channel (121) formed by the total heat exchange plate (12) is connected to the sensible heat exchange channel (111) formed by the sensible heat exchange plate (11), thereby forming a first fluid channel and a second fluid channel that flow in opposite directions inside the heat exchanger shell (1). The inner pipe (21) is provided with an inner pipe inlet (211) at the top and an inner pipe outlet (212) on the side. The first fluid channel includes an outdoor fresh air inlet (6), the outlet end of which is connected to the inlet end of the first total heat exchange channel (1211), the outlet end of the first total heat exchange channel (1211) is connected to the inlet end of the first sensible heat exchange channel (1111), the outlet end of the first sensible heat exchange channel (1111) is connected to the inlet end of the outer pipe (22), and the outlet end of the outer pipe (22) is connected to the outdoor fresh air outlet (7) on the side of the double-layer central axis pipe (2). The second fluid channel includes an indoor exhaust inlet (8), the outlet end of which is connected to the inner layer pipe inlet (211), the inner layer pipe inlet (211) is connected to the inner layer pipe outlet (212) through the inner layer pipe (21), the inner layer pipe outlet (212) is connected to the inlet end of the second sensible heat exchange channel (1112), the outlet end of the second sensible heat exchange channel (1112) is connected to the inlet end of the second total heat exchange channel (1212), and the outlet end of the second total heat exchange channel (1212) is connected to the indoor exhaust outlet (9) on the side of the heat exchanger shell (1).

2. The air heat exchange device suitable for scenarios with large temperature differences or large enthalpy differences according to claim 1, characterized in that, The outer surfaces of the sensible heat exchange plate (11) and the total heat exchange plate (12) are provided with a heat insulation layer (5).

3. The air heat exchange device suitable for scenarios with large temperature differences or large enthalpy differences according to claim 1, characterized in that, Condensate baffles (4) are provided at the connection between the total heat exchange plate (12) and the sensible heat exchange plate (11), and at the connection between the total heat exchange plate (12) and the double-layer central axial pipe (2).

4. The air heat exchange device suitable for scenarios with large temperature differences or large enthalpy differences according to any one of claims 1 to 3, characterized in that, The heat exchanger shell (1) is provided with a condensate drain outlet (3) at the bottom.

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