CN211953818U - High-energy-efficiency-ratio environmental-grade heat exchanger for closed space - Google Patents

Abstract

The utility model provides an environmental-grade heat exchanger with high energy efficiency ratio in a closed space, which comprises an evaporator, a steam pipeline, a condenser, a liquid pipeline, a liquid storage device, a heat transfer working medium and a fan assembly; the evaporator is fixedly arranged in the cabinet to be radiated, and the condenser is arranged outside the space of the cabinet; the device overall forms a two-phase fluid loop, and the heat transfer working medium is arranged in the two-phase fluid loop; the condenser also comprises an upper top frame, a lower bottom frame and a plurality of fin plates which are vertically arranged in an array; the fin plate is provided with a plurality of micro-channels which are vertically arranged in an array; and fan assemblies are arranged on the rear sides of the evaporator and the condenser. The utility model discloses an airtight space high energy efficiency ratio environmental level heat exchanger, its effective heat transfer area is big, bottom heat transfer technique heat transfer capacity is strong, therefore the heat exchanger heat transfer capacity is strong, has high energy efficiency ratio.

Description

High-energy-efficiency-ratio environmental-grade heat exchanger for closed space

Technical Field

The utility model belongs to the technical field of heat abstractor, concretely relates to high energy efficiency ratio environmental level heat exchanger in airtight space.

Background

The communication base station, the energy storage power station, the electric power cabinet, the control cabinet and other electric equipment need to be installed in a heat-insulating closed space due to the requirements of safety, dust prevention, moisture prevention, temperature control and the like, and the closed space is isolated from the outside heat, so that effective heat control measures need to be adopted to ensure the safe and reliable operation of internal equipment. Usually, the heat generated inside is offset by air-conditioning refrigeration to maintain a proper internal environment temperature level, but the heat control cost of using the air conditioner is high, the power consumption of the air conditioner accounts for about 50% of the total power consumption, and in order to reduce the heat control cost, an environmental natural cold source needs to be efficiently introduced for heat control of a closed space.

At present, the natural cold source introduced by the thermal control of the closed space mainly has several modes. (1) The building envelope is improved: the requirement of thermal control in a closed environment is not met; (2) the frequency conversion technology and the like are adopted to improve the efficiency of the air conditioner in the machine room: COP improvement space is limited; (3) refrigeration/heat pipe double-cycle air conditioner: the heat exchanger is not well matched, and the comprehensive energy efficiency of the system is not high; (4) fresh air system: the environment cold energy is introduced, and meanwhile, moisture and dust are introduced, so that the requirements on cleanliness and humidity of a closed space are not met; (5) an environment-grade heat exchanger: the method does not introduce moisture and dust, only introduces environment cold, has large cold introduction amount, and is a natural cold source introduction mode with optimal heat control of the closed space.

The heat exchange capacity of the environmental-grade heat exchanger is characterized by an energy efficiency ratio COP (coefficient of performance) Q/W (coefficient of performance), which is defined as the ratio of the heat exchange quantity to the operating power and mainly depends on the heat transfer capacity and the effective heat exchange area of the bottom layer heat transfer technology.

The traditional environment-level heat exchanger is a dividing wall type heat exchanger, a secondary refrigerant heat exchanger or a heat pipe type heat exchanger. The dividing wall type heat exchanger is used for forced convection heat exchange of air, the heat exchange coefficient is small, and the heat exchange area is small; the heat exchange area of the secondary refrigerant heat exchanger is large, but the heat transfer capacity of the pump driving fluid loop is limited, and extra pump power is needed; the heat pipe type heat exchanger has a large heat exchange area, but the gravity heat pipe has small heat transfer capacity. Therefore, the traditional environment-level heat exchanger has limited heat exchange capacity and low energy efficiency ratio. The utility model provides an airtight space high energy efficiency ratio environmental level heat exchanger to improve the problem that traditional environmental level heat exchanger energy efficiency ratio is low.

For the purposes of understanding the principles of operation of the present application, a highly efficient passive heat transfer technique based on a temperature difference driven self-circulating two-phase fluid loop is described in detail herein. The high-efficiency passive heat transfer technology refers to a heat transfer technology having a high heat transfer capability, requiring no external power (i.e., having high reliability).

The heat exchange carried out by the phase change latent heat is several orders of magnitude larger than the heat transferred by a single relative flow system in a sensible heat mode, and meanwhile, the efficient passive heat transfer technology is usually constructed on the basis of the phase change heat exchange without external power.

The high-efficiency passive heat transfer technology has wide engineering application scenes.

In a heat utilization scene, the method relates to the field of efficient utilization of cold quantity, such as cold conduction of a semiconductor refrigerator, cold conduction of a Stirling refrigerator, LNG (liquefied natural gas) cold quantity transmission, a thawing plate and the like; and the fields of high-efficiency utilization of heat, such as high-efficiency utilization of solar energy, utilization of low-grade heat energy of ground source/water source/air source, utilization of industrial waste heat, thermoelectric generation, IH-like electric cooker inner containers and the like.

In a thermal control scene, the heat dissipation field of electronic devices is related, such as 5G equipment, LEDs, lasers, phased array radar T/R components, CPUs (home computers/servers/mobile phones), IGBTs (frequency converters/photovoltaic inverters/extra-high voltage direct current transmission), semiconductor refrigerators, power batteries, proton exchange membrane fuel cells and the like; and the field of heat exchange of closed spaces, such as base stations, data centers, power cabinets, naval vessel engine cabins and the like.

1. Principle of system

The fundamental idea of strengthening the phase change heat exchange is to increase the phase change heat exchange quantity in unit time, namely, to increase the product of the phase change rate and the phase change latent heat.

On one hand, the whole phase change period covers the whole process of bubble nucleation, bubble growth, bubble detachment and bubble polymerization rise; on the other hand, the phase transition rate and the phase transition latent heat are closely related parameters on the physical aspect, so the improvement of the product of the two parameters needs to be based on the comprehensive analysis of the bubble nucleation and the kinetic characteristics of the phase transition complete cycle.

2. Intensification of the phase transition Rate

2.1 bubble nucleation theory

The vapor bubbles in the boiling process all develop from the core of vaporization (i.e., the tiny vapor bubbles).

The vaporization core of the volume boiling is generated spontaneously, and is caused by fluctuation of the density of each part of the liquid around the average value due to the energy distribution nonuniformity of liquid molecules (according to the molecular motion theory, the energy of each molecule in the liquid is unequal and is distributed according to a certain rule, the nonuniformity of the molecular energy distribution enables the density of each part of the liquid to fluctuate around the average value, temporary local tiny low-density areas are formed due to the random aggregation of activated molecules with larger energy, and the small low-density areas are considered to be tiny vapor bubbles with certain radius and molecular number, which is the formation process of tiny vapor saturated cores in the liquid phase), and the degree of superheat of hundreds is needed.

The vaporization cores of the boiling in the pool are provided outside and are pits, slits and cracks on the heating wall surface (firstly, the liquid in the slits on the heating surface is influenced by much more heating than the same amount of liquid on the plane, and is easy to vaporize to generate steam, and secondly, the gas in the slits is easy to remain, and the gas naturally becomes the vaporization cores for generating bubbles), and the superheat degree is smaller.

As shown in FIG. 1, a container is provided, the bottom surface of which is heated and the upper surface of which is provided with a pressure p_sCorresponds to t_sE.g. with a bubble in the middle, with internal pressure p_vTemperature t_vAmbient fluid corresponds to p_l、t_l。

The conditions under which the bubbles are stable are thermal equilibrium and force equilibrium:

(1) heat balance: t is t_l＝t_v

If t_l＜t_vThen the bubbles transfer heat to the fluid, the steam in the bubbles condenses, and the bubbles collapse;

if t_l＞t_vThen the fluid transfers heat to the vapor bubble, the vapor in the vapor bubble expands, and the vapor bubble grows up.

(2) Force balance: p is a radical of_v-p_l＝2γ/R

If p is_v-p_lIf the pressure difference between two sides of the steam bubble is less than 2 gamma/R, the pressure difference between two sides of the steam bubble is not enough to resist surface tension, steam in the steam bubble is condensed, and the steam bubble is collapsed;

if p is_v-p_lIf the pressure difference is more than 2 gamma/R, the pressure difference of two sides of the steam bubble is more than the surface tension, the steam in the steam bubble expands, and the steam bubble grows up.

For the force balance condition, without considering the static pressure,

p_l＝p_s

then there is a change in the number of,

is the rate of change of pressure on a vapor-liquid two-phase saturation line with temperature, and is constant for a certain pressure. According to the relation between the pressure variation along with the temperature on the saturation line and each parameter of the saturation state, the Clausius-Clabailong provides the following calculation formula:

wherein r is the latent heat of vaporization at the saturation temperature,ρ_vand rho_lRespectively the density of the vapor and liquid within the bubble. When boiling away from the critical point, ρ_v＜＜ρ_lThen, the above formula is simplified as follows:

the substitution above can result in:

in the case of boiling, the liquid has a maximum superheat at the wall, Δ t ═ t_v-t_s＝t_w-t_sTherefore, the bubble generation condition is satisfied at the wall surface first, and the minimum radius of the wall surface when the bubble nucleus is generated is as follows:

the above formula shows that under certain conditions of p and delta t, the primary bubble nucleus can grow continuously only when the radius of the primary bubble nucleus is larger than the value, and the above formula is the minimum radius of the primary bubble nucleus for standing the foot.

If the vaporized core in the pit can not grow any more, the pit is an inactive pit, i.e., an inactive nucleation site. The vaporization core in the pit grows until the vaporization core grows to expose the opening of the pit, and the radius of a small vapor bubble exposing the opening (which can be approximately regarded as the radius of the opening of the pit) is larger than or equal to the critical radius of the vapor bubble corresponding to the superheat degree of a given liquid, so that the vaporization core can continue to grow, and the pit is called an activation pit, namely an activation nucleation point.

Critical activation nucleation point radius r_mCritical core of vaporization R_min＝2γT_s/rρ_vΔ T, where γ is the surface tension coefficient of the working fluid, T_sIs the saturation temperature at local pressure, r is the latent heat of vaporization at saturation temperature, ρ_vIs the saturated steam density, Δ t ═ t_w-t_sThe superheat degree of the liquid working medium on the wall surface. The boiling heat exchange intensity (or phase change rate) on the wall surface depends on the total number of activated nucleation points on the heating wall surface, and the size distribution density of pits on the heating wall surface is approximate to a normal distribution function N with the origin as the starting point_rThus total number of activated nucleation sites

I.e. the radius r of the heating wall surface is larger than the critical activation nucleation point_mThe pits of (a) are all activation nucleation sites. Thus, the ways to increase the total number of activated nucleation sites N fall into two categories: firstly, a layer of porous structure is formed on the heating wall surface, and the normal distribution function N is increased_rThe expectation and standard deviation of the activation nucleation sites N can be multiplied by the method; secondly, the phase change working medium is modified at a certain saturation temperature T_sAnd the critical activation nucleation point radius r is reduced under the condition of the wall surface superheat degree delta t_mThis method can increase the total number of activated nucleation sites N by several orders of magnitude.

2.2 gas dynamic theory

The dynamics of the vapor bubble mainly researches the growth and movement rule of the vapor bubble in the liquid.

(1) The bubble grows, the vaporization core formed on the activation nucleation point can grow continuously under various forces. The early stage is a dynamic control stage, the growth of the bubbles is mainly governed by internal thermal inertia force and external surface tension, and the growth rate of the bubbles is very high; the latter is a heat transfer control stage, which is extended for a longer time, with the bubble growth rate being dominated by the heat transfer capacity from the heated liquid to the vapor bubble, the bubble growth rate being slower when the liquid is saturated liquid and faster when the liquid is superheated liquid (discussed at point (2.3)).

(2) Bubble detachment phase, bubble detachment diameter D from heated wall_dThe smaller the detachment frequency f, the higher the phase transition rate. Wherein the bubble detachment diameter D_dThe influencing factors comprise the decreasing with the increasing of the system pressure, the proportional relation with the-1/3 th power of the gravity acceleration, the influence of the inertia force in the case of negative pressure (the pressure is lower than the atmospheric pressure), and the like(ii) a The bubble disengagement frequency f has a relationship

For the kinetic control phase, the index n is 2, and for the heat transfer control phase, the index n is 1/2. Therefore, the bubble separation diameter D can be reduced by modifying the working medium_dMeanwhile, the bubble separation frequency f is increased, and the phase change rate is further enhanced.

(3) In the bubble polymerization rising period, the heat exchange between the bubbles and the liquid in the rising process can reach very high strength (discussed at (2.3)), so that the effective discharge of the bubbles can improve the critical heat flow density under the working condition of high heat flow density, the polymerization and rising movement of the bubbles are very complex, and the bubbles are related to complex gas-liquid two-phase turbulence, and the current research is in the initial stage. But a reasonable bubble discharge structure can be designed to effectively discharge bubbles, thereby strengthening the phase change rate.

The method integrates (1) and (2) nub analysis, modifies the phase change working medium based on the phase change characteristic of the phase change full cycle, and reduces the radius r of the critical activation nucleation point from the physical property level_mTo increase the total number of activated nucleation sites N; reducing the bubble separation diameter D from the physical layer_dIncreasing the bubble separation frequency f to further enhance the phase change rate.

2.3 theory of superheated boiling

In the boiling process, in the heat transfer control stage at the later stage of bubble growth, the bubble growth rate is mainly governed by the heat transfer capacity from liquid to vapor bubble, and the superheat degree of the liquid determines the growth rate of the bubbles; in the rising stage of bubble polymerization, the superheat degree of the liquid determines the heat exchange strength between the vapor bubble and the liquid in the rising process. The bubble growth rate can be enhanced by designing the liquid working medium as superheated liquid.

The boiling state when the temperature of the liquid main body reaches the saturation temperature is saturated boiling, and bubbles can grow slowly in the liquid after being separated from the wall surface; the boiling state that the main body temperature of the liquid is lower than the saturation temperature is supercooling boiling, and the bubbles can disappear in the liquid after separating from the wall surface; the boiling state in which the bulk temperature of the liquid exceeds the saturation temperature is superheated boiling, and bubbles grow rapidly in the liquid after leaving the wall surface. Therefore, the liquid working medium is designed to be an overheat liquid, namely, an overheat boiling state is established.

For heterogeneous boiling on the overheating wall surface, the temperature of the liquid working medium is from the heating of the overheating wall surface, the liquid body is difficult to obtain larger superheat degree in a wall surface heating mode, therefore, the boiling point of the working medium is required to be reduced in a mode of reducing boiling interface pressure, and the overheating boiling is realized under the condition that the liquid working medium obtains heat only through the wall surface heating.

In order to reduce the boiling interface pressure, a phase change cycle must be constructed. The complete two-phase fluid loop comprises an evaporator, a steam pipeline, a condenser, a liquid pipeline and a liquid storage device, the two-phase fluid loop is driven by temperature difference to carry out self circulation, and the circulating power can be gravity or capillary force.

(1) The pressure-temperature diagram of a two-phase fluid loop thermodynamic cycle when the cycle power is gravity is shown in figure 2.

Wherein the content of the first and second substances,

1: an evaporation interface within the evaporator;

1 → 2: the steam is continuously heated in the evaporator to form superheated steam-delta P_eva；

2 → 3: steam flows in the steam line-delta P_vap；

3 → 4: cooling steam in the condenser;

4 → 5: condensing steam in the condenser;

5 → 6: supercooling of liquid in condenser-total of the three items Δ P_con；

6 → 8: liquid flowing in the liquid pipe-delta P_liq；

7: a reservoir;

gravity pressure difference delta P as circulating power_gTotal flow pressure loss Δ P_total＝ΔP_eva+ΔP_vap+ΔP_con+ΔP_liq。

(2) When the circulation power is capillary force, the pressure-temperature diagram of the thermodynamic circulation of the two-phase fluid loop is similar to the upper diagram, and the flow pressure difference delta P in the capillary core is increased in the circulation_wic。

Corresponding to capillary pressure difference DeltaP as circulation power_cTotal flow pressure loss Δ P_total＝ΔP_eva+ΔP_vap+ΔP_con+ΔP_liq+ΔP_wicIf the evaporator is in the antigravity working condition, the capillary wick correspondingly provides the total flow resistance delta P_totalAnd gravity head Δ P_gThe circulating power of (2). During thermal equilibrium of the system, the radius of the meniscus in the evaporator is automatically adjusted to match the flow resistance of the fluid circuit, which is the heat transfer capacity limit of the system when the radius of the meniscus is equal to the capillary aperture.

Under any circulating power condition, the boiling interface temperature of the two-phase fluid loop is T₁Pressure of P₈The boiling environment at this time is lower than the saturation pressure + the saturation temperature, that is, the superheated boiling state.

In an overheat boiling state, the liquid working medium is overheat liquid, and in a heat transfer control stage at the later stage of bubble growth, the overheat liquid transfers heat to the vapor bubble in a large amount, and the growth rate of the bubble is high; in the bubble polymerization rising stage, the superheated liquid also transfers a large amount of heat to the bubbles, and the heat exchange strength between the bubbles and the liquid is higher, so that the phase change rate is enhanced.

By integrating the summary analysis of (2.1) - (2.3), the critical activation nucleation point radius r can be reduced from the physical property level by modifying the phase change working medium_mTo increase the total number N of activation nucleation points and to decrease the bubble separation diameter D from the physical aspect_dIncreasing the bubble separation frequency f to ensure that the heat transfer working medium has higher phase change rate in the bubble nucleation and bubble separation process of the phase change full period, thereby strengthening the phase change rate; the vapor-liquid separation is realized by designing a two-phase fluid loop and by a capillary structure, a liquid pool structure and a height difference structure, so that the phase change interface pressure of the heat transfer working medium in the evaporator is reduced, a hot boiling state is further established, the heat exchange strength of the vapor heat transfer working medium and the liquid heat transfer working medium is increased in the process of bubble growth and bubble polymerization in the phase change full period, and the phase change rate is further enhanced.

3. Intensification of latent heat of phase change

Latent heat of phase change means working medium of unit mass when temperature is not changedHeat absorbed or released during the phase change. The latent heat of phase change comprises an internal work part for overcoming the interaction potential energy between molecules to do work and an external work part for overcoming the atmospheric pressure to do work. The internal work is a main component, and the potential energy of intermolecular interaction includes intermolecular forces such as van der waals force and hydrogen bond. Van der waals' force is a weakly basic electrical attraction, also called intermolecular force, that exists between neutral molecules or between inert gas atoms; hydrogen bonds exist between nonmetal atoms with large electronegativity and small atomic radius such as F, O and N and hydrogen, and molecules with hydrogen bonds include HF and H₂O and NH₃And the like.

The intermolecular forces of working media with similar physical shapes in the same temperature zone are not different greatly, for example, water, ethanol and acetone are all liquid at normal temperature and normal pressure, and the intermolecular forces are different by only a few times. That is, the latent heat of phase change between different working mediums in a certain temperature area is usually only several times different.

Therefore, when the product of the phase change rate and the phase change latent heat is comprehensively considered in the enhanced phase change heat exchange, the phase change rate enhanced by several orders of magnitude can be realized, and the phase change latent heat with the difference of several times in the same temperature region is considered.

4. System components

The high-efficiency passive heat transfer technology based on the temperature difference driven self-circulation two-phase fluid loop is designed by combining the analysis of the enhanced phase change rate and the enhanced phase change latent heat, mainly comprises an evaporator, a steam pipeline, a condenser, a liquid pipeline, a liquid storage device and a modified heat transfer working medium, the system is a closed loop, the product of the phase change rate and the phase change latent heat of the system is large, the phase change heat exchange capacity is strong, and the high-efficiency passive heat transfer technology is ideal.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing an airtight space high energy efficiency ratio environmental level heat exchanger to improve the problem that traditional environmental level heat exchanger energy efficiency ratio is low. The key points are to improve the effective heat exchange area and increase the heat transfer capability of the bottom layer heat transfer technology.

In order to solve the technical problem, the utility model discloses a technical scheme is:

an environmental-grade heat exchanger with a closed space and a high energy efficiency ratio comprises an evaporator, a steam pipeline, a condenser, a liquid pipeline, a liquid storage device and a heat transfer working medium;

wherein the evaporator is fixedly arranged in the closed space (generally a cabinet to be radiated), and the condenser is arranged outside the closed space; preferably, the condenser is located higher than the evaporator.

The evaporator comprises a steam outlet and a liquid inlet, and the condenser comprises a steam inlet and a liquid outlet;

the steam outlet of the evaporator is connected with the steam inlet of the condenser through a steam pipeline; the liquid inlet hole of the evaporator is connected with the liquid outlet hole of the condenser through a liquid pipeline; the device as a whole forms a two-phase fluid loop;

the evaporator and the condenser are both provided with a plurality of micro-channels, the micro-channels are arranged in a vertical array (the expansion joint finned tubes of the tube-fin heat exchanger are arranged in a vertical array), and the arrangement height of the condenser is higher than that of the evaporator; the liquid storage device is connected on the liquid pipeline in parallel, when the working temperature rises, the volume of the liquid working medium is increased, and redundant liquid working medium overflows into the liquid storage device through the connecting pipe. The evaporator and the condenser adopt a micro-channel brazing process or a drawing and expanding process, and the integral forming adopts a brazing process.

The rear sides of the evaporator and the condenser are respectively provided with a fan assembly, the fan assemblies guide airflow to fully contact the evaporator, so that the evaporator can more efficiently absorb heat in a closed cabinet body (in a cabinet), and compared with the condenser, the fan assemblies help the condenser to dissipate heat.

The working principle is as follows:

the utility model discloses bottom heat transfer technique reaches high-efficient heat transfer effect through reinforceing phase transition heat transfer for the high-efficient passive heat transfer technique based on difference in temperature drive self-loopa two-phase fluid return circuit.

The fundamental idea of strengthening the phase change heat exchange is to increase the phase change heat exchange quantity in unit time, namely, to increase the product of the phase change rate and the phase change latent heat. On one hand, the whole phase change period covers the whole process of bubble nucleation, bubble growth, bubble detachment and bubble polymerization rise; on the other hand, the phase transition rate and the phase transition latent heat are closely related parameters on the physical aspect, so the improvement of the product of the two parameters needs to be based on the comprehensive analysis of the bubble nucleation and the kinetic characteristics of the phase transition complete cycle.

By modifying the phase change working medium, the critical activation nucleation point radius r is reduced from the physical property level_mTo increase the total number N of activation nucleation points and to decrease the bubble separation diameter D from the physical aspect_dIncreasing the bubble separation frequency f to ensure that the heat transfer working medium has higher phase change rate in the bubble nucleation and bubble separation process of the phase change full period, thereby strengthening the phase change rate; by designing a two-phase fluid loop and realizing vapor-liquid separation through a height difference structure, the phase change interface pressure of the heat transfer working medium in the evaporator is reduced, and further a hot boiling state is established, so that the heat exchange strength of the vapor heat transfer working medium and the liquid heat transfer working medium is increased in the processes of bubble growth and bubble polymerization in the phase change full period, and the phase change rate is further enhanced.

The utility model has the advantages that:

on the one hand, the utility model discloses an evaporimeter and condenser adopt microchannel technology or auxetic technology, and microchannel or inside pipeline internal flow channel are covered with heat transfer working medium, and all fins all play the heat transfer effect, and heat transfer area is big.

On the other hand, the utility model discloses bottom heat transfer technique is based on the high-efficient passive heat transfer technique of difference in temperature drive self-loopa two-phase fluid return circuit, and the product of phase transition rate and phase transition latent heat is synthesized with dynamic characteristic to the bubble nucleation based on the phase transition full cycle. The technology has the characteristics of large heat/high heat flow density heat transfer capacity, high heat transfer speed, long heat transfer distance, small system thermal resistance and high reliability. The heat transfer capacity is greatly improved compared with the air forced convection heat exchange of a dividing wall type heat exchanger, and the gravity heat pipe of a pump driving fluid loop or a heat pipe type heat exchanger of a secondary refrigerant heat exchanger.

To sum up, the utility model relates to an airtight space high energy efficiency ratio environmental level heat exchanger, its effective heat transfer area is big, bottom heat transfer technique heat transfer capacity is strong, therefore heat exchanger heat transfer capacity is strong, has high energy efficiency ratio.

Drawings

FIG. 1 is a background art illustration;

FIG. 2 is a background art illustration;

fig. 3 is a schematic structural diagram of the closed space high energy efficiency ratio environmental grade heat exchanger of the present invention;

FIG. 4 is a schematic view of the evaporator, the housing, and the fan assembly of the present invention;

FIG. 5 is a schematic cross-sectional view of the microchannel of the closed space high energy efficiency ratio environmental grade heat exchanger of the present invention;

fig. 6 is an alternative to the evaporator of the present invention.

Detailed Description

The following describes the present invention with reference to the accompanying drawings. It should be noted that the description of the embodiments is provided to help understanding of the present invention, but the present invention is not limited thereto. In addition, the technical features related to the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

As shown in fig. 3-5, the enclosed space environment-level heat exchanger with high energy efficiency ratio comprises an evaporator 1, a steam pipeline 2, a condenser 3, a liquid pipeline 4, a liquid reservoir 5, a heat transfer working medium 6 and a fan assembly 7;

wherein the evaporator 1 is fixedly arranged in the closed space (generally a cabinet 9 to be radiated), and the condenser 3 is arranged outside the closed space; preferably, the condenser 3 is disposed at a position higher than the evaporator 1.

The evaporator 1 comprises a steam outlet and a liquid inlet, and the condenser 3 comprises a steam inlet and a liquid outlet;

the steam outlet of the evaporator 1 is connected with the steam inlet of the condenser 3 through a steam pipeline 2; the liquid inlet hole of the evaporator 1 is connected with the liquid outlet hole of the condenser 3 through a liquid pipeline 4; the device overall forms a two-phase fluid loop, and the heat transfer working medium 6 is arranged in the two-phase fluid loop (namely in the evaporator 1, the steam pipeline 2, the condenser 3, the liquid pipeline 4 and the liquid storage device 5);

the condenser 3 further comprises an upper top frame 31, a lower bottom frame 32 and a plurality of fin plates 33 which are vertically arranged in an array; the fin plate 33 is provided with a plurality of micro-channels 331 which are vertically arranged in an array;

the upper top frame 31 and the lower bottom frame 32 are hollow tubes with a cavity in the middle, and two ends of each tube are sealed; the outer wall of the lower bottom surface of the upper top frame 31 is provided with a plurality of strip-shaped jacks, and the outer wall of the upper surface of the lower bottom frame 32 is provided with a plurality of strip-shaped jacks;

the upper and lower ends of the fin plate 33 are respectively inserted into the strip-shaped insertion holes of the upper top frame 31 and the lower bottom frame 32.

The fin plate 33 is provided with a plurality of vertical array arrangement micro-channels 331, and the upper end and the lower end of each micro-channel 331 are respectively communicated with the cavities of the upper top frame 31 and the lower bottom frame 32.

The heat transfer working medium 6 is prepared by 40-60% of propine, 20-30% of DME (dimethyl ether), 10-15% of methyl chloride and 5-10% of nano titanium powder;

or the heat transfer working medium 6 is prepared from 40 to 60 parts of propine, 20 to 30 parts of DME, 10 to 15 parts of methyl chloride and 5 to 10 parts of nano titanium powder.

The rear sides of the evaporator 1 and the condenser 3 are both provided with fan assemblies 7, the fan assemblies 7 guide airflow to fully contact the evaporator 1, so that the evaporator 1 can more efficiently absorb heat in a closed cabinet body (in the cabinet), and the heat dissipation of the condenser 3 is facilitated compared with the heat dissipation of the condenser 3.

Preferably, the evaporator further comprises two shells 8, and the evaporator 1 and the fan assembly 7 are arranged in the inner cavity of the shells; the condenser 3 is arranged in the inner cavity of the shell cover 8.

This application increases effective heat transfer area through adopting microchannel 331 or auxetic mode:

the micro-channel 331 section specification can select 60mm 2mm (width x thickness), 32mm 2mm, 25.4mm 2mm, etc.;

as shown in fig. 6, the evaporator 1 may be of a tube fin type (fins not shown); the expansion tubes can be copper tubes or aluminum tubes, the fins can be copper fins or aluminum fins, and the number of rows of the copper tubes can be single or multiple;

the heat exchange mode between the evaporator 1 and the condenser 3 and the air is forced convection;

the sizes and the volumes of all functional parts of the evaporator 1, the steam pipeline 2, the condenser 3, the liquid pipeline 4 and the liquid storage device 5 need to be matched and designed based on the technical requirements of working medium physical properties and heat transfer capacity of a working temperature zone.

The heat transfer capacity is improved by adopting a high-efficiency passive heat transfer technology based on a temperature difference driving self-circulation two-phase fluid loop:

the system working medium is in a vapor-liquid two-phase state in a working temperature region and has a critical activation nucleation point radius r_mSmall, bubble-free diameter D_dSmall, high bubble separation frequency f, and high phase change rate;

the filling amount of the system working medium needs to consider the sizes and the volumes of functional parts of the evaporator 1, the steam pipeline 2, the condenser 3, the liquid pipeline 4 and the liquid storage device 5, the physical properties of the working medium in a working temperature region and the technical requirements on heat transfer capacity;

the system working medium filling needs to adopt special high-precision filling and seal welding complete equipment, and the error between the actually obtained filling quantity requirement and the design value is not more than 1%.

The working process is as follows:

the evaporator 1 in the two-phase fluid loop absorbs the heat of air inside the closed environment, the liquid working medium 6 inside the closed environment evaporates at a phase change interface, the vapor working medium is transmitted to the condenser 3 through the vapor pipeline 2, the vapor working medium in the condenser 3 is firstly cooled, then condensed and finally supercooled, the liquid working medium is transmitted to the liquid storage device 5 through the liquid pipeline 4, and the liquid working medium in the liquid storage device 5 is supplemented to the evaporator 1 for continuous evaporation. The circulating power of the fluid loop is gravity, and the working medium 6 in the two-phase fluid loop is driven by temperature difference to perform self-circulation flow along the path of the evaporator 1 → the condenser 3.

The embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. It will be apparent to those skilled in the art that various changes, modifications, substitutions and alterations can be made in the embodiments without departing from the principles and spirit of the invention, and the scope of the invention is to be accorded the full scope of the claims.

Claims (8)

1. The utility model provides an environmental level heat exchanger of high energy efficiency ratio in airtight space which characterized in that: the system comprises an evaporator, a steam pipeline, a condenser, a liquid pipeline, a liquid storage device, a heat transfer working medium and a fan assembly;

the evaporator is fixedly arranged in the cabinet to be radiated, and the condenser is arranged outside the space of the cabinet;

the evaporator comprises a steam outlet and a liquid inlet, and the condenser comprises a steam inlet and a liquid outlet;

the steam outlet of the evaporator is connected with the steam inlet of the condenser through a steam pipeline; the liquid inlet hole of the evaporator is connected with the liquid outlet hole of the condenser through a liquid pipeline;

the device overall forms a two-phase fluid loop, and the heat transfer working medium is arranged in the two-phase fluid loop;

the condenser also comprises an upper top frame, a lower bottom frame and a plurality of fin plates which are vertically arranged in an array; the fin plate is provided with a plurality of micro-channels which are vertically arranged in an array;

and fan assemblies are arranged on the rear sides of the evaporator and the condenser.

2. The enclosed space energy efficiency ratio environmental grade heat exchanger according to claim 1, characterized in that: the upper top frame and the lower bottom frame are hollow tube bodies with cavities in the middle parts, and two ends of the tube bodies are sealed; the outer wall of the lower bottom surface of the upper top frame is provided with a plurality of strip-shaped jacks, and the outer wall of the upper surface of the lower bottom frame is provided with a plurality of strip-shaped jacks;

the upper end and the lower end of the fin plate are respectively arranged in the strip-shaped jacks of the upper top frame and the lower bottom frame in a penetrating manner;

the fin plate is provided with a plurality of vertical array arrangement micro-channels, and the upper end and the lower end of each micro-channel are respectively communicated with the cavities of the upper top frame and the lower bottom frame.

3. The enclosed space high energy efficiency ratio environmental grade heat exchanger according to claim 2, characterized in that: it also comprises two shells; the evaporator and the fan assembly are arranged in the inner cavity of the shell; the condenser is arranged in the inner cavity of the shell cover.

4. The enclosed space energy efficiency ratio environmental grade heat exchanger according to claim 3, characterized in that: the condenser is arranged at a position higher than the evaporator.

5. The enclosed space energy efficiency ratio environmental grade heat exchanger according to claim 1, characterized in that: the fin plate is a copper fin or an aluminum fin.

6. The enclosed space energy efficiency ratio environmental grade heat exchanger according to claim 1, characterized in that: the section caliber of the micro-channel is rectangular.

7. The enclosed space energy efficiency ratio environmental grade heat exchanger according to claim 1, characterized in that: the cross-sectional shape of the microchannel is oval or circular.

8. The enclosed space energy efficient ratio environmental grade heat exchanger according to claim 6, wherein: the micro-channel has a dimension specification of 60mm × 2mm or 32mm × 2mm or 25.4mm × 2 mm.

Images