1. A heat exchange core is characterized by comprising a base material and a functional material, wherein the functional material contains a phase-change heat storage material.

2. The heat exchange core according to claim 1, wherein the phase change heat storage material contains a compound capable of forming a hydrated salt with a phase change temperature of 5-50 ℃.

3. The heat exchange core according to claim 2, wherein the compound capable of forming a hydrated salt with a phase transition temperature of 5 to 50 ℃ is selected from the group consisting of LiCl, CaCl₂、LiBr、CaBr₂、FeBr₃、LiNO₃、Mg(NO₃)₂、Ca(NO₃)₂、Zn(NO₃)₂、CH₃COONa、CaCl₂、Na₂CO₃、Na₂SO₄、MgSO₄、K₂HPO₄And hydrates thereof.

4. The heat exchange core according to any one of claims 1 to 3, wherein the functional material is attached as a layer of functional material to a surface of the substrate.

5. The heat exchange core according to any one of claims 1 to 3, wherein the functional material is distributed in the substrate.

6. The heat exchange core according to any one of claims 1 to 3, wherein the base material comprises 40 to 99.5 wt% of the total weight of the heat exchange core, and the functional material comprises 0.5 to 60 wt% of the total weight of the heat exchange core.

7. The heat exchange core according to any one of claims 1 to 3, wherein the heat exchange core is composed of a plurality of porous heat exchange units arranged along the airflow direction, and a preset gap is formed between adjacent porous heat exchange units.

8. The heat exchange core according to claim 7, wherein the predetermined gap has a thickness of 0.1cm to 5 cm.

9. The heat exchange core according to claim 7, wherein the thickness of the porous heat exchange unit is 0.2 cm-10 cm per plate, the porosity is 0.3-0.85, and the pore diameter of the porous heat exchange unit is 0.1 cm-2 cm.

10. A heat recovery fresh air device, characterized in that it comprises a heat exchange core according to any one of claims 1 to 9.

Background

According to the ASHVE (american society of heating and ventilation engineers) report, the temperature at which a human body feels comfortable is about 27.7% in summer, 22% in winter, and the relative humidity value at which a human body feels comfortable is 35% to 65%. Humans maintain the temperature and humidity of indoor air within a comfortable range by consuming energy. According to statistics, the building operation energy consumption accounts for 30% of the global total energy consumption, and even reaches 40% in developed countries. About 50% of the energy consumption for building operation is consumed by HVAC (heating, ventilation and air conditioning) systems. Therefore, reducing the energy consumption of buildings in HVAC is an important direction for humans to reduce carbon dioxide emissions and ultimately achieve carbon neutralization.

As is known, the ventilation is carried out indoors, so that harmful gas in the room can be effectively exhausted, and outdoor fresh air is introduced into the room, thereby being beneficial to the health of human bodies. The process of natural ventilation of the building through windowing can bring great energy loss, and further can increase the energy consumption of heating/refrigerating equipment of the building. Especially, under the condition of large temperature/humidity difference between the indoor and the outdoor, the energy consumption of building operation can be greatly increased by windowing and ventilating the building indoor.

Therefore, the method has important significance for adopting heat recovery measures during building ventilation and reducing the building operation energy consumption. In order to recover heat in air, most of heat exchange equipment adopted by existing fresh air systems in the current market is based on a bidirectional flow technology, and a heat exchange core body is arranged in the heat exchange equipment, so that cold air and hot air are converged in the heat exchange equipment to exchange heat. However, the bidirectional flow heat exchange type fresh air system collects dirty air and distributes fresh air, and a large number of pipelines are needed besides the heat exchanger, so that the whole fresh air system has the defects of complex structure, high cost, difficult installation, uncleanability of pipelines and the like, and is easy to propagate pollution. For example, most central fresh air systems are not used during new crown epidemic situations.

In addition, in the existing reciprocating ventilation technology, airflow periodically flows through the ventilation system, the aim of indoor ventilation of the building is fulfilled, and the heat core is replaced in the ventilation system to recover energy. By adopting the ventilation technology, the heat exchange core is required to have good heat storage and release performance, air permeability and other performances.

The heat exchange core in the reciprocating heat recovery fresh air system is a core component of the system, and the performance of the heat exchange core is directly related to the heat recovery performance effect. When the latent heat of the airflow is recycled, the evaporation and condensation of water vapor in the air are respectively heat absorption and heat release processes. This requires both the heat exchange core to have moisture absorption/release functions and the heat exchange core to have a high specific heat capacity.

How to improve the heat exchange core in the reciprocating heat recovery fresh air system to improve the heat recovery efficiency and reduce the energy consumption is an urgent technical problem to be solved in the field.

Disclosure of Invention

In view of the above technical problems in the prior art, the inventors of the present invention have conducted extensive studies and found that by adding a phase change heat storage material to a material serving as a heat exchange core in a reciprocating heat recovery fresh air system, the heat capacity of the heat exchange core can be greatly improved by utilizing the characteristic of large latent heat of the phase change heat storage material, thereby improving the heat recovery efficiency of the heat exchange core during operation and reducing the energy consumption of building operation.

In order to solve the technical problems, the invention adopts the following technical scheme.

In one aspect, the invention provides a heat exchange core, which comprises a base material and a functional material, wherein the functional material comprises a phase-change heat storage material.

In the heat exchange core of the present invention, preferably, the phase change heat storage material contains a compound capable of forming a hydrated salt, the phase change temperature of which is 5 to 50 ℃.

Preferably, the compound capable of forming a hydrated salt and having a phase transition temperature of 5-50 ℃ is selected from LiCl and CaCl₂、LiBr、CaBr₂、FeBr₃、LiNO₃、Mg(NO₃)₂、Ca(NO₃)₂、Zn(NO₃)₂、CH₃COONa、CaCl₂、Na₂CO₃、Na₂SO₄、MgSO₄、K₂HPO₄At least one of (1).

Preferably, the aforementioned functional material is attached to the surface of the substrate as a functional material layer.

Preferably, the aforementioned functional material is distributed in the substrate.

Preferably, the base material accounts for 40-99.5% of the total weight of the heat exchange core, and the functional material accounts for 0.5-60% of the total weight of the heat exchange core.

Preferably, the heat exchange core is composed of a plurality of porous heat exchange units arranged along the airflow direction, and a preset gap is formed between every two adjacent porous heat exchange units.

Preferably, the thickness of the preset gap is 0.1 cm-5 cm.

Preferably, the thickness of each porous heat exchange unit is 0.2 cm-10 cm, the porosity is 0.3-0.85, and the pore diameter of the porous heat exchange unit is 0.1 cm-2 cm.

On the other hand, the invention also relates to a heat recovery fresh air device which comprises the heat exchange core.

In the heat recovery fresh air device, a reciprocating heat recovery fresh air device is preferred, and the heat recovery fresh air device also comprises at least one fan unit and at least one ventilation pipeline.

The heat exchange core disclosed by the invention contains the phase-change heat storage material, and the heat capacity of the heat exchange core can be greatly improved by utilizing the large latent heat of the phase-change heat storage material, so that the heat recovery efficiency of the heat exchange core during working is improved, and the energy consumption of building operation is reduced.

Drawings

In the drawings, which are not necessarily drawn to scale, like reference numerals may describe similar components in different views. Like reference numerals having letter suffixes or different letter suffixes may represent different instances of similar components. The drawings illustrate various embodiments, by way of example and not by way of limitation, and together with the description and claims, serve to explain the inventive embodiments. The same reference numbers will be used throughout the drawings to refer to the same or like parts, where appropriate. Such embodiments are illustrative, and are not intended to be exhaustive or exclusive embodiments of the present apparatus or method.

Fig. 1 is a graph showing the temperature distribution along the airflow direction of a heat exchange core in summer (obtained by processing pictures taken by an infrared camera) according to an embodiment of the present invention.

Fig. 2 is a perspective assembled view of a heat exchange core according to an embodiment of the present invention.

Fig. 3 is an exploded perspective view of a heat exchange core according to an embodiment of the present invention.

Fig. 4 is a schematic view of a heat recovery fresh air device according to an embodiment of the present invention.

Fig. 5 is a schematic view of a heat recovery fresh air device according to another embodiment of the present invention.

Reference numerals:

1-a fan; 2, a wall body; 3-a heat exchange core; 31-a porous heat exchange unit; 32-shell.

Detailed Description

Detailed descriptions of known functions and known components are omitted. Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs. In order to make the following description of the present invention easier to understand, some terms are described as follows:

"Heat exchange core" refers to the components of a heat recovery ventilation system that provide for the exchange of sensible and latent heat with a circulating air stream. In operation of the heat recovery ventilation system, the air flow is typically periodically reciprocated, and the core is periodically subjected to a heat accumulation/release process, thereby blocking energy loss from the air flow inside and outside the chamber.

"Heat" in heat exchange, heat exchange core, and the like, refers to the generic term sensible and latent, as used herein, in the context of the present invention, as equivalent to enthalpy.

The heat exchange core provided by the invention is provided with a base material and a functional material, wherein the functional material contains a phase-change heat storage material.

The base material may be any of commonly used ceramics, diatomaceous earth, metals, alloys, plastics, and the like, and is not particularly limited, and preferably is at least one selected from the group consisting of oxides, carbides, nitrides, and alloys. Examples of the oxide material include alumina, magnesia, silica, iron oxide, and the like; examples of the carbide material include titanium carbide, silicon carbide, and the like; examples of the nitride material include silicon nitride, titanium nitride, and the like; examples of the alloy include stainless steel, copper alloy, and aluminum alloy; as the plastic material, for example, PP plastic, PE plastic, PC plastic, and the like can be cited.

The phase-change heat storage material has the property of changing the state of a substance and providing latent heat under the condition of constant temperature, the process of changing the state of the substance is called a phase-change heat storage process, and a large amount of latent heat is absorbed or released in the phase-change heat storage process. Examples of the phase change heat storage material that can be used in the heat exchange core include an organic phase change heat storage material and an inorganic phase change heat storage material. Examples of the organic phase change heat storage material include paraffin, stearyl alcohol, stearic acid, formic acid, acetic acid, and lauric acid. Examples of the inorganic phase change heat storage material include the above-mentioned hydrated salts. It is preferable to use an inorganic phase change heat storage material.

The latent heat of the phase-change heat storage material can greatly improve the heat capacity of the heat exchange core. For example, LiClO₄·3H₂The latent heat of O phase change is 253kJ/kg, KF.4H₂The latent heat of O phase change is 330kJ/kg, CaCl₂·6H₂The latent heat of O phase transition was 180 kJ/kg. The effect of the phase change material is on the one hand to increase the thermal inertia of the heat exchanger core. The heat inertia of the heat exchange core is large, and the thickness of the heat exchange core can be reduced, so that the resistance of airflow flowing through the heat exchange core can be reduced, the power consumption of unit ventilation volume is reduced, and the efficiency of the fresh air device is improved. On the other hand, the phase-change material absorbs and releases heat during the phase change process, but the temperature is not changed, which is beneficial to improving the humidity regulating function of the heat exchange core when the heat exchange core plays the humidity regulating function. For example, when the heat exchange core absorbs moisture, the water vapor carried by the air flow is absorbed by the heat exchange core and releases heat. At this time, the heat capacity of the heat exchange core is large, so the temperature rise change is small, if the heat exchange core is just at the phase change temperature of the contained phase change material, the temperature of the heat exchange core is kept unchanged, and the heat exchange core is favorable for further absorbing water vapor. On the contrary, if the heat capacity of the heat exchange core is small, the temperature of the heat exchange core can be raised by latent heat released when the water vapor is absorbed by the heat exchange core, so that the relative humidity of air flow is reduced, the humidity regulation is not facilitated, and the sensible heat recovery is also not facilitated.

In the heat exchange core of the invention, preferably, the phase-change heat storage material is a compound capable of forming a hydrated salt, and the phase-change temperature of the compound is 5-50 ℃.

The inventor finds that in the phase-change heat storage material, the compound which has the phase-change temperature of 5-50 ℃ and can form hydrated salt is particularly suitable for the heat exchange core material of a fresh air system because the phase-change heat storage temperature is between the normal atmospheric temperature and the indoor temperature of a building. For the compound which has the phase transition temperature of 5-50 ℃ and can form hydrated salt, the phase transition temperature is 5-50 ℃, is in the atmospheric temperature range and is close to the indoor temperature of a building, so the phase transition process can happen in the ventilation process of the ventilation device, which is beneficial to improving the heat recovery efficiency of the heat exchange core, or the geometric dimension of the heat exchange core can be smaller under the condition of the same heat recovery efficiency, thereby increasing the ventilation volume of the ventilation device.

Preferably, the compound capable of forming a hydrated salt with a phase transition temperature of 5-50 ℃ is selected from LiCl and CaCl₂、LiBr、CaBr₂、FeBr₃、LiNO₃、Mg(NO₃)₂、Ca(NO₃)₂、Zn(NO₃)₂、CH₃COONa、CaCl₂、Na₂CO₃、Na₂SO₄、MgSO₄、K₂HPO₄And hydrates thereof.

LiCl、CaCl₂、LiBr、CaBr₂、FeBr₃、LiNO₃、Mg(NO₃)₂、Ca(NO₃)₂、Zn(NO₃)₂、CH₃COONa、CaCl₂、Na₂CO₃、Na₂SO₄、MgSO₄、K₂HPO₄Are all salts capable of forming hydrates. When these salts exist in a state of containing no water, they can absorb water and have a moisture absorbing function, and when a relatively dry air flow is passed through the hydrated salts after they are formed into a hydrated salt form, the hydrated salts can lose their hydrated water and have a moisture releasing function. Thus, the salts and their hydrated salts can function as a phase change material for storing heat and can regulate the humidity of the air flow. For the heat recovery process involved in building ventilation, the process of conditioning moisture is equivalent to latent heat energy recovery.

The aforementioned hydrated salts also include partially hydrated salts. For example, as MgSO₄Of (2) hydrated salt of (2) MgSO 2₄·1H₂O、MgSO₄·2H₂O、MgSO₄·3H₂O、MgSO₄·4H₂O、MgSO₄·5H₂O、MgSO₄·6H₂O、MgSO₄·7H₂O, etc. contain hydrated salts of varying water content.

The range of humidity for human comfort is 30-60% relative humidity, while the relative humidity outside the building is often significantly different from the range of humidity for human comfort. For example, in the summer of south China, there is often sauna weather with high humidity, and in the winter of north China, there is also often dry weather with low relative humidity. In this case, ventilation of the building requires the humidity of the air to be adjusted.

By using the aforementioned LiCl, CaCl₂、LiBr、CaBr₂、FeBr₃、LiNO₃、Mg(NO₃)₂、Ca(NO₃)₂、Zn(NO₃)₂、CH₃COONa、CaCl₂、Na₂CO₃、Na₂SO₄、MgSO₄、K₂HPO₄And at least one of their hydrates as phase change heat storage materials, which allow the humidity of the air flow to be adjusted while heat is recovered by these materials. It is thus preferable from this point of view to have both heat recovery and humidity conditioning functions for the heat exchanger core of the present invention.

In some embodiments of the present invention, in the heat exchange core of the present invention, the phase-change heat storage material may optionally further contain at least one selected from alkanes and fatty acids. Examples of such phase change heat storage materials include heptadecane, octadecane, eicosane, paraffin, octadecanol, stearic acid, formic acid, acetic acid, and lauric acid.

Further, in order to adjust the humidity of the air flow passing through the heat exchange core, the functional material may further contain other materials having a humidity adjustment function in addition to the salt capable of forming a hydrate. Examples of such humidity control materials include natural clay and natural vermiculite. By containing these humidity control materials, the humidity of the air flow passing through the heat exchange core can be further adjusted.

Hereinafter, the temperature and humidity control method in the case where the heat exchange core of the present invention is used in a heat recovery fresh air device will be described.

When the outdoor temperature is high and the humidity is high, the temperature and the humidity need to be reduced indoors to meet the comfortable temperature and humidity environment of a human body. When the heat exchange core is used in equipment for building ventilation, in the process that air sent into a room by a fan flows through the heat exchange core, the functional materials in the heat exchange core absorb heat and water vapor carried by the air flow, so that the temperature and the humidity of the air flow are reduced, and the temperature and the relative humidity of the air flow flowing into the room are closer to the temperature and the humidity meeting the requirement of human comfort. On the contrary, when the air is exhausted to the outdoor, the heat and the vapor absorbed by the heat exchange core are taken away by the air flow flowing out from the indoor in the process that the turbid air flows through the heat exchange core. By alternately and periodically carrying out the air supply and exhaust processes, turbid air is discharged out of the room, fresh air enters the room, and meanwhile, the temperature and the humidity of the indoor air can be adjusted by utilizing the heat exchange core.

On the other hand, when the outdoor temperature is low and the humidity is low, the indoor of the building needs to be heated and humidified to meet the comfortable temperature and humidity environment of the human body. In such a case, when air is supplied to the room, the air flow absorbs heat and water vapor from the heat exchange core while passing through the heat exchange core of the present invention, and the temperature and relative humidity of the air flow when passing through the room are closer to those meeting the requirement of comfort for human body. On the contrary, when the air is exhausted outdoors, in the process that turbid air flows through the heat exchange core, heat and vapor carried by the air flow are transferred to the heat exchange core. The air supply and the air exhaust are carried out alternately and periodically, so that turbid air is exhausted out of the room, fresh air enters the room, and the temperature and the humidity of the indoor air can be adjusted by utilizing the heat exchange core.

The functional material may contain other components in addition to the phase change heat storage material and the humidity control material, without affecting the heat recovery and humidity control functions of the phase change heat storage material and the humidity control material.

Examples of such a component include a binder for coating on a substrate. Examples of the binder include water glass, bentonite, and silica sol.

In the heat exchange core, as for the mixture ratio of the base material and the functional material, the base material accounts for 40-99.5% of the total weight of the heat exchange core, and the functional material accounts for 0.5-60% of the total weight of the heat exchange core.

The aforementioned functional material may be attached to the surface of the substrate, for example, as a functional material layer. As the functional material layer, the functional material may be formed on the base material by, for example, spraying, dipping, or deposition.

In addition, the functional material may be mixed with the base material in the form of powder or the like and molded into the shape of the heat exchange core. In this case, the aforementioned functional material is distributed in the aforementioned base material. The molding method is not particularly limited.

The heat exchange core of the present invention has a porous structure, and the aforementioned porosity may be, for example, a honeycomb shape, a foam shape, or the like, and is not particularly limited. The porosity of the porous material may be, for example, 0.3 to 0.85, preferably 0.6 to 0.7.

Preferably, the heat exchange core of the present invention is composed of a plurality of porous heat exchange units arranged along the airflow direction, and a preset gap is provided between adjacent porous heat exchange units.

The plurality of sheets refers to two or more sheets. The number of sheets of the porous heat exchange unit constituting the heat exchange core is not particularly limited. For example, 2 to 20 sheets, preferably 2 to 10 sheets, are used from the viewpoint of obtaining more excellent heat recovery efficiency.

When the air current flows through porous heat transfer unit, because of having between the adjacent porous heat transfer unit and predetermine the clearance, should predetermine the clearance and be the air intermediate layer, through having this air intermediate layer, can slow down the speed that the air current passes through the heat transfer core on the one hand, and then can hinder the heat-conduction of heat transfer core in the air current flow direction for the air current through the heat transfer core can carry out abundant heat exchange with the heat transfer core, reduces the calorific loss that the ventilation process led to the fact for indoor to a great extent.

The shape of the pores in the porous heat exchange unit is not particularly limited, and may be a honeycomb shape, a foam shape, or the like, like the pores in the heat exchange core. In view of processing cost, a honeycomb shape is preferable. The cross-section of the micro-channels is not particularly limited, and may be, for example, triangular, quadrangular, hexagonal, polygonal, circular, or elliptical. Considering both the flow resistance and the heat exchange, a regular hexagon is preferable. These porous shapes may be due to the pores of the substrate itself forming the porous heat exchange units. These porous shapes may be formed in the process of molding after the base material and the functional material are uniformly mixed.

The porous heat exchange unit can be formed by cutting a whole heat exchange core body or can be manufactured separately. The thickness of the porous heat exchange unit is not particularly limited, and may be appropriately set according to the heat exchange efficiency, and is preferably, for example, 1cm to 5 cm.

The thickness of the predetermined gap between the adjacent porous heat exchange units is not particularly limited. The thickness of the predetermined gap may be set to match the thickness of the porous heat exchange unit, and may be, for example, 0.1cm to 5cm, and is preferably, for example, 0.1cm to 0.5cm from the viewpoint of obtaining an improved heat exchange effect.

In some embodiments, the heat exchange core further comprises a shell. As shown in fig. 2 and 3, a housing 32 is provided outside the plurality of porous heat exchange units 31, and a predetermined gap is maintained between the porous heat exchange units 31 by passing an air flow through the housing 32 in a space covered by the housing 32, and by providing partitions or positioning grooves (not shown) in the housing 32. The porous heat exchange unit 31 is wrapped and fixed by the shell 32 to form the whole heat exchange core. The thickness, porosity, pore diameter, constituent materials and the like of each porous heat exchange unit can be the same or different. The thickness, porosity, pore diameter, constituent materials and the like of each porous heat exchange unit and the overall thickness of the heat exchange core can be determined appropriately according to the climate environment of the geographical position of the building used by the fresh air system. The shape of the cross section of the heat exchange core is not particularly limited, and the heat exchange core can be circular, quadrangular, polygonal, oval and the like according to the shape of the ventilation pipe or the structure of the fresh air system.

The aforementioned manner of arranging the casing and arranging the partition or the positioning groove on the casing is not particularly limited to the manner of arranging the preset gap, as long as the gap can be formed between the aforementioned porous heat exchange units.

[ Heat recovery fresh air device ]

The invention also discloses a heat recovery fresh air device which comprises the heat exchange core.

In the heat recovery fresh air device, the heat exchange core is contained, and the heat storage performance of the phase change heat storage material contained in the heat exchange core is utilized, so that better heat exchange efficiency can be obtained, and the heat loss caused to the indoor space in the ventilation process can be reduced.

The heat recovery fresh air device of the present invention includes other necessary components, such as a fan, a ventilation duct, and the like, in addition to the heat exchange core, and these components are not particularly limited. Those skilled in the art can appropriately set the setting as needed.

Preferably, the heat recovery fresh air device of the present invention is a reciprocating heat recovery fresh air device, which further comprises at least one fan unit and at least one ventilation duct.

The reciprocating hot fresh air device comprises a positive and negative rotation fan, and the positive and negative rotation fan periodically rotates. When the indoor air is exhausted to the outdoor, the indoor air is exhausted to the outdoor after passing through the heat exchange core and the ventilation pipe in sequence, and at the moment, the heat exchange core stores heat. On the contrary, under the condition that outdoor air is led into the room through the ventilation pipe and the heat exchange core in sequence, the air is heated by utilizing the heat stored in the heat exchange core. The circulation is repeated in a periodic way, so that when air enters the room, the consumption of indoor heat caused by ventilation can be reduced.

Fig. 4 and 5 respectively show schematic diagrams of the heat recovery fresh air device of the invention. Fig. 4 shows an embodiment in which the heat exchange core is placed in a ventilation pipe together with a fan, and the ventilation pipe is embedded in a wall body. FIG. 5 shows an embodiment in which the fan is placed inside the ventilation tube, the ventilation tube is embedded in the wall, and the heat exchange core is placed inside the room and clings to the wall. Conventional components in the field such as an air filtering system, an outdoor rainproof air port of a ventilation pipe, an indoor air guide port and the like can be appropriately arranged as required by a person skilled in the art, and are not described in detail herein.

Further, the heat exchange core under different conditions is subjected to simulation analysis by adopting a numerical simulation method. The simulated working condition environment is the condition of reciprocating ventilation at the indoor temperature of 20 ℃ and the outdoor temperature of-20 ℃. The ventilation speed is 0.5 m/s, and the commutation period is 60 s. The heat exchange core was integrated, the heat exchange core consisted of 4 layers, and the heat capacity of the heat exchange core was increased by 20% respectively. Fig. 1 shows the distribution of the air flow temperature along the thickness direction of the heat exchange core at the end of air intake and air exhaust in the case of 3 heat exchange cores. The standard for judging the quality of the heat exchange core is as follows: when exhausting air, the lower the temperature of the gas exhausted to the outside is, the better; and when the air is supplied, the higher the temperature of the air entering the room, the better. As can be seen from the figure, the performance of the three heat exchange cores is ordered as follows:

the heat capacity of the heat exchange core is enlarged by 20% >4 layers of heat exchange cores > whole heat exchange core.

According to a calculation formula of the heat recovery efficiency, the heat recovery efficiency of the heat exchange core is increased by twenty percent by 3 types of heat exchange core heat capacities, namely 89.31%, 88.99% and 88.50% of the heat recovery efficiency of the heat exchange core with the 4-layer structure under the conditions through analyzing the result of numerical simulation. Particularly, in terms of ventilation effect, the average temperature of inlet air of the three heat exchange cores within 60 seconds is respectively 15.58 ℃, 15.45 ℃ and 15.25 ℃. It can be seen that the heat recovery efficiency is improved by 0.3-0.5%, while the average inlet air temperature is about 0.4 ℃. It is clear that the heat recovery efficiency can be further improved by further increasing the number of layers of the heat exchange core and/or taking into account the latent heat of phase change.

The above embodiments are only exemplary embodiments of the present invention, and are not intended to limit the present invention, and the scope of the present invention is defined by the claims. Various modifications and equivalents may be made by those skilled in the art within the spirit and scope of the present invention, and such modifications and equivalents should also be considered as falling within the scope of the present invention.