Cross countercurrent flow heat exchange device suitable for heat pump unit

Abstract

The utility model discloses a cross countercurrent heat exchange device suitable for a heat pump unit, and relates to the technical field of enhanced heat transfer. The heat exchange device comprises a flow divider, a flow collector, a heat exchange part, a fan and a shell. The heat exchange part comprises a heat exchange coil and fins; one end of the heat exchange coil pipe is communicated with the flow divider, and the other end of the heat exchange coil pipe is connected with the flow collector; the fins are arranged on the heat exchange coil pipe in a sleeving mode in the direction perpendicular to the heat exchange coil pipe. The shell covers the outer side of the flow divider, the outer side of the flow collector, the outer side of the heat exchange coil pipe, the outer side of the fin and the outer side of the draught fan, ventilation holes are further formed in the shell, and the ventilation holes and the draught fan are oppositely arranged. According to the utility model, the logarithmic average temperature difference between air and a refrigerant can be increased, so that the heat exchange efficiency of a unit is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of enhanced heat transfer, in particular to a cross-countercurrent heat exchange device suitable for a heat pump unit. Background Art

[0002] At present, it is urgent to gradually replace fossil energy with renewable energy in the field of heating / cooling. Air energy is inexhaustible and can be combined with heat pump technology as a cold / heat source for the unit, which is one of the best ways to achieve zero-carbon heating / cooling in the future. Although air source heat pump units have broad application prospects, due to the small air convection heat transfer coefficient, compared with water source, soil source, etc., air source heat pump units have low energy efficiency. It is urgent to further improve the heat exchange efficiency of the unit, reduce the energy consumption of the unit, and thus obtain a higher performance coefficient (COP).

[0003] The outdoor heat exchanger used in traditional air source heat pump units mostly adopts the form of vertical coil + fin. The purpose of vertical arrangement is to ensure that the refrigerant at the outlet is all liquid when the outdoor heat exchanger is used as a condenser, so that it can pass through the expansion valve smoothly. But in fact, because the inertia of liquid is greater than that of gas, even if the refrigerant before the expansion valve is in a gas-liquid two-phase state, only liquid refrigerant can flow through.

[0004] At the same time, the vertical arrangement of multiple heat exchange coils will lead to a poor overall heat exchange effect of the outdoor heat exchanger. During the heat exchange process, the outdoor air that vertically passes over the surface of the ribbed coil first contacts the front row heat exchange coil, and then exchanges heat with the rear row heat exchange coil in sequence. As the temperature of the air gradually rises after absorbing heat, the heat exchange temperature difference between the rear row heat exchange coil and the air decreases, and the heat exchange effect deteriorates. Utility Model Content

[0005] The utility model aims to provide a cross-countercurrent heat exchange device suitable for a heat pump unit, which can increase the logarithmic mean temperature difference between air and refrigerant, thereby improving the heat exchange efficiency of the unit.

[0006] To achieve the above purpose, the utility model provides the following solutions:

[0007] A cross-countercurrent heat exchange device suitable for a heat pump unit comprises: a diverter, a collector, a heat exchange part, a fan and a shell; the heat exchange part comprises a heat exchange coil and fins; one end of the heat exchange coil is connected to the diverter, and the other end of the heat exchange coil is connected to the collector; the fins are sleeved on the heat exchange coil in a direction perpendicular to the heat exchange coil; the shell is covered on the outside of the diverter, the collector, the heat exchange coil, the fins and the fan, and the shell is also provided with ventilation holes, which are arranged opposite to the fan.

[0008] Optionally, the heat exchange coil is in the form of a horizontally arranged serpentine coil, including at least 4 heat exchange processes.

[0009] Optionally, every two adjacent heat exchange processes are connected by a U-shaped bend, and the U-shaped bend forms an angle with a horizontal plane.

[0010] Optionally, the heat exchange coil is provided with a plurality of fins, and each of the fins is integrally sleeved on the heat exchange coil in a series.

[0011] Optionally, the diverter uses a large diameter heat exchange tube.

[0012] Optionally, the current collector is in the form of a liquid separation head.

[0013] Optionally, the heat exchange parts are arranged as one group or two groups; when the heat exchange parts are arranged as one group, the heat exchange parts are arranged in parallel with the fans; when the heat exchange parts are arranged as two groups, the heat exchange parts are arranged in a V shape, and the fans are arranged at the V-shaped mouth.

[0014] According to the specific embodiments provided by the utility model, the utility model discloses the following technical effects:

[0015] The utility model discloses a cross-countercurrent heat exchange device suitable for a heat pump unit, comprising a flow divider, a flow collector, a heat exchange unit, a fan and a housing; the heat exchange unit comprises a heat exchange coil and a fin; one end of the heat exchange coil is connected to the flow divider, and the other end of the heat exchange coil is connected to the flow collector; the fin is sleeved on the heat exchange coil in a direction perpendicular to the heat exchange coil; the housing is covered on the outer side of the flow divider, the flow collector, the heat exchange coil, the fin and the fan, and a ventilation hole is also opened on the housing, and the ventilation hole is arranged opposite to the fan. The utility model can increase the logarithmic mean temperature difference between air and refrigerant, thereby improving the heat exchange efficiency of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0017] Figure 1 Schematic diagram of the appearance of the outdoor cross-counterflow heat exchange device in this embodiment;

[0018] Figure 2 It is a side view of the outdoor cross-counterflow heat exchange device in this embodiment;

[0019] FIG3( a ) is a pressure-enthalpy diagram of the outdoor cross-countercurrent heat exchange device used as a condenser in this embodiment;

[0020] FIG3( b ) is a pressure-enthalpy diagram of the outdoor cross-countercurrent heat exchange device used as an evaporator in this embodiment;

[0021] Figure 4 This is a front view of the outdoor cross-counterflow heat exchange device in this embodiment when a V-shaped arrangement is adopted;

[0022] FIG5(a) is a cycle flow chart of an outdoor cross-countercurrent heat exchange device connected to an air conditioning system under cooling conditions in this embodiment;

[0023] FIG5( b ) is a cycle flow chart of the outdoor cross-counterflow heat exchange device connected to the air conditioning system under heating conditions in this embodiment.

[0024] Figure numerals: 1. diverter; 2. collector; 3. heat exchange coil; 4. fin; 5. fan; 6. casing; 7. U-bend; 8. outdoor cross-countercurrent heat exchange coil; 9. indoor heat exchanger; 10. compressor; 11. expansion valve; 12. four-way reversing valve. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0026] The utility model aims to provide a cross-countercurrent heat exchange device suitable for a heat pump unit, which can increase the logarithmic mean temperature difference between air and refrigerant, thereby improving the heat exchange efficiency of the unit.

[0027] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0028] like Figure 1As shown, in view of the defect of low heat exchange efficiency of vertically arranged heat exchange coils in outdoor heat exchangers used in traditional air source heat pump units, in order to fully and efficiently exchange heat with the outside air to improve the heating / cooling performance of the unit, the utility model provides a cross-countercurrent heat exchange device suitable for a heat pump unit, comprising: a diverter 1, a collector 2, a heat exchange part, a fan 5 and a shell 6; the heat exchange part comprises a heat exchange coil 3 and a fin 4; one end of the heat exchange coil 3 is connected to the diverter 1, and the other end of the heat exchange coil 3 is connected to the collector 2; the fin 4 is sleeved on the heat exchange coil 3 in a direction perpendicular to the heat exchange coil 3; the shell 6 is covered on the outside of the diverter 1, the collector 2, the heat exchange coil 3, the fin 4 and the fan 5, and the shell 6 is also provided with ventilation holes, and the ventilation holes are arranged opposite to the fan 5.

[0029] The heat exchange coil 3 is arranged in a horizontal serpentine shape to form a horizontal branch. The number of branches and the number of processes of the heat exchange coil can be increased or decreased according to the designed heat exchange capacity and the allowed placement space, but the number of processes of each heat exchange coil must be at least 4 to ensure that the heat exchange mode when the refrigerant in the tube crosses and counterflows with the air outside the tube can be regarded as a complete countercurrent heat exchange. Adjacent processes are connected by U-shaped bends 7, and the bends are at a certain angle to the horizontal plane to enhance airflow disturbance and promote heat exchange.

[0030] The fins 4 and the heat exchange coil 3 together form a heat exchange part. The integral sleeve-type fins 4 are arranged vertically to the heat exchange coil 3. The fin spacing, fin form and fin material can be adjusted after weighing the design heat exchange capacity and the air side pressure drop.

[0031] A variable frequency axial flow fan 5 is provided at the rear of the heat exchange unit to suck outdoor air for forced convection heat exchange with the heat exchange unit. The outer shell 6 acts as a wind shield, enclosing the upper, lower, left and right sides of the heat exchange unit so that the air sucked by the fan 5 flows as vertically as possible through the surface of the heat exchange unit.

[0032] According to the number of branches of the heat exchange coil, the refrigerant in the tube is divided into multiple branches accordingly. In cooling operation, the refrigerant enters from the splitter 1 and exits from the collector 2; in heating operation, the refrigerant enters from the collector 2 and exits from the splitter 1. Therefore, when the heating / cooling mode is switched, the refrigerant flow direction changes, and the inverter is used to change the direction of the fan 5 to ensure that the air flow direction is always opposite to the general trend of the refrigerant flow direction.

[0033] like Figure 2As shown, in order to adapt to the large changes in refrigerant flow and pressure in the heat exchange coil when switching between heating and cooling conditions, the diverter 1 is made of a large-diameter heat exchange tube, and the collector 2 is in the form of a liquid distributor. The arrangement of the liquid distributor allows the gas-liquid two-phase refrigerant entering the heat exchange coil from the collector 2 to be evenly distributed to each branch when the unit switches from a cooling condition to a heating condition. However, regardless of the cooling condition or the heating condition, the refrigerant entering or exiting the diverter 1 is a gaseous refrigerant, which is easier to distribute and collect, so a diverter tube can be used. The two are arranged on the same side of the heat exchange coil when the number of flow paths is an even number, and on the opposite sides of the heat exchange coil when it is an odd number.

[0034] In addition, the device has a simple structure and low cost for achieving enhanced heat exchange. By changing the arrangement direction of the heat exchange coil 3, the general trend of the refrigerant flow direction is changed from the traditional vertical direction to the horizontal direction, so that the countercurrent heat exchange between the refrigerant and the air can be achieved, thereby enhancing the heat exchange. The present invention breaks the design concept of the traditional air-cooled condenser and can transform the existing outdoor heat exchanger. It has the advantages of simple structure, easy promotion and simple control.

[0035] Based on the above technical solution, the following specific implementation methods are provided:

[0036] As shown in Figure 3(a), under cooling conditions, the state of the refrigerant inside the air source heat pump unit with a traditional vertical coil outdoor heat exchanger can be represented by the cycle process of node 1-node 2-node 3-node 4-node 1 in the pressure-enthalpy diagram. In order to ensure that the refrigerant before the expansion valve is all liquid, it is usually necessary to increase the heat exchange area of ​​the liquid refrigerant and reduce the heat exchange area of ​​the gaseous refrigerant to form a certain degree of recooling at the condenser outlet. At this time, the refrigerant state process becomes node 1-node 2'-node 3'-node 4'-node 1. Due to the reduction in the heat exchange area of ​​the gaseous refrigerant, the refrigerant condensation rate decreases and the condensation pressure increases. Compared with before, the cooling capacity per unit mass of refrigerant increases from q0 to q0', but the unit power consumption of the compressor also increases from w th Increase to w th If the device is installed in the heat pump unit, the heat exchange efficiency of the outdoor heat exchanger will be improved, the condensation rate will increase, and the condensation pressure will be reduced (by P k Downgrade to P k ”), the refrigeration cycle becomes node 1-node 2”-node 3”-node 4”-node 1. Not only the refrigeration capacity per unit mass of refrigerant increases from q0 to q0”, but also the unit power consumption of the compressor increases from w th Reduced to w th ”, thus having a larger cooling COP.

[0037] As shown in Figure 3(b), under heating conditions, the cycle process of the air source heat pump unit with a traditional vertical coil outdoor heat exchanger is node 1-node 2-node 3-node 4-node 1. After switching to a horizontal coil outdoor heat exchanger, the evaporation rate increases and the evaporation pressure increases (from P0 to P0”), so the heating cycle becomes node 1”-node 2-node 3-node 4”-node 1”. The amount of heat absorbed by the outdoor heat exchanger from the low-temperature heat source increases from q0 to q0”, and the power consumption of the compressor 10 increases from w th Reduced to w th ", the heating COP of the unit is also improved.

[0038] like Figure 4 As shown, the design concept of this embodiment can also be used in large air source heat pump units. The two sets of heat exchange parts are arranged in a V shape, and the heat exchange coils are arranged horizontally. When the fan 5 above draws air, the outdoor air on both sides flows almost vertically through the surface of the heat exchange part and converges upward inside. In order to make the general trend of air flow opposite to that of refrigerant flow to achieve countercurrent heat exchange, the refrigerant in the heat exchange coil can only flow from the inside to the outside.

[0039] The analysis is carried out using the example of the splitter and collector on the opposite sides. As shown in Figure 5(a), the air conditioning system consists of an outdoor cross-countercurrent heat exchange coil 8, an indoor heat exchanger 9, a compressor 10, an expansion valve 11, a four-way reversing valve 12, etc. When operating in cooling mode, the refrigerant in the outdoor cross-countercurrent heat exchange coil 8 flows in from the lower opening of the splitter 1 and is distributed to each horizontal branch by the splitter pipe. After condensation, it is collected in the collector 2 and flows out. When operating in heating mode, the gas-liquid two-phase refrigerant at the outlet of the expansion valve 11 flows in from the collector 2, and the refrigerant is evenly distributed to each branch by the liquid distributor. After heat exchange and evaporation with the outdoor air, it flows out from the lower opening of the splitter 1, as shown in Figure 5(b). Regardless of whether the air source heat pump unit uses the outdoor cross-countercurrent heat exchange coil 8 as an evaporator or a condenser, since the refrigerant in the diverter 1 is always in a gaseous state and the refrigerant in the collector 2 is always in a gas-liquid two-phase state, and the volume of the gaseous refrigerant will shrink after liquefaction, the diameter of the diverter pipe is larger than the diameter of the diverter header.

[0040] This outdoor cross-counterflow heat exchange coil 8 for air source heat pump units has a wide range of applications. It can not only be used in the fields of civil (household applications) and commercial (office buildings, schools, hotels, hospitals, etc.) heating and cooling, but also provide a reliable implementation method for reducing the energy consumption of building operations. At the same time, it can also be used across industries in the fields of industrial and agricultural drying and storage, the fields of constant temperature breeding in agriculture and animal husbandry, and the field of thermal management technology for new energy vehicles.

[0041] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0042] This article uses specific examples to illustrate the principle and implementation of the utility model. The above examples are only used to help understand the core idea of ​​the utility model. At the same time, for those skilled in the art, according to the idea of ​​the utility model, there will be changes in the specific implementation and application scope. In summary, the content of this specification should not be understood as limiting the utility model.

Claims

1. A cross-countercurrent heat exchange device suitable for a heat pump unit, characterized in that: include: A flow divider, a flow collector, a heat exchange part, a fan and a shell; the heat exchange part includes a heat exchange coil and a fin; one end of the heat exchange coil is connected to the flow divider, and the other end of the heat exchange coil is connected to the flow collector; the fin is sleeved on the heat exchange coil in a direction perpendicular to the heat exchange coil; the shell is covered on the outer sides of the flow divider, the flow collector, the heat exchange coil, the fin and the fan, and the shell is also provided with a ventilation hole, and the ventilation hole is arranged opposite to the fan; The heat exchange coil is in the form of a horizontally arranged serpentine coil, including at least 4 heat exchange processes; every two adjacent heat exchange processes are connected by a U-shaped bend, and there is an angle between the U-shaped bend and the horizontal plane; the diverter uses a large-diameter heat exchange tube.

2. The cross-countercurrent heat exchange device suitable for a heat pump unit according to claim 1, characterized in that: The heat exchange coil is provided with a plurality of fins, and each of the fins is integrally sleeved on the heat exchange coil in a series.

3. The cross-countercurrent heat exchange device suitable for a heat pump unit according to claim 1, characterized in that: The current collector is in the form of a liquid separation head.

4. The cross-countercurrent heat exchange device suitable for a heat pump unit according to claim 1, characterized in that: The heat exchange parts are arranged in one group or two groups; when the heat exchange parts are arranged in one group, the heat exchange parts are arranged in parallel with the fans; when the heat exchange parts are arranged in two groups, the heat exchange parts are arranged in a V shape, and the fans are arranged at the V-shaped opening.

Images