Finned heat exchanger for air energy heat pump

Abstract

The utility model provides a finned heat exchanger for an air energy heat pump, which is characterized by comprising fins, a supercooling inlet pipe, a supercooling outlet pipe, a flow dividing head, a liquid dividing capillary pipe and a gas collecting pipe, and the supercooling outlet pipe is connected with the flow dividing head; flow paths at the bottoms of the fins are all in an S shape, and flow paths at the upper portions of the fins are all in an n shape. During heating, the flow of a flow path at the bottom of the fin is increased, the temperature of the bottom area of the fin is increased, and the frosting degree of the bottom area of the fin is reduced. And during defrosting, the flow and the temperature of a flow path at the bottom of the fin are increased, frost at the bottom and ice water flowing down from the upper part are quickly and thoroughly removed, and bottom freezing is avoided. In the defrosting process, the overall temperature and heat distribution of the fins are reasonably allocated, heat is fully utilized, the defrosting time is shortened, and the defrosting energy consumption is reduced.

Description

Technical Field

[0001] The utility model relates to an air source heat pump device, and more specifically to a finned heat exchanger for an air energy heat pump. Background Art

[0002] The finned heat exchanger used in an ultra-low temperature air energy heat pump is a heat exchanger that exchanges heat between a refrigerant and air by means of a circulating fan. During operation, the refrigerant inside the copper tube of the heat exchanger evaporates and absorbs heat or condenses and releases heat, and the air is cooled or heated by heat transfer through the copper tube and the fins on the surface of the copper tube. It has the characteristics of high efficiency, compactness, lightness, and strong adaptability, and is an important component of an ultra-low temperature air energy heat pump. At present, the following problems will occur in the operation of the finned heat exchanger in an ultra-low temperature air energy heat pump:

[0003] 1. The finned heat exchanger is particularly prone to frosting in low-temperature and high-humidity areas. As time goes by, the frost water on the upper part of the heat exchanger flows to the bottom area of the fins under the influence of gravity, resulting in the most serious frosting in the bottom area of the fins.

[0004] 2. When the finned heat exchanger is defrosting, the ice water generated by defrosting the upper part of the heat exchanger flows to the bottom area under the influence of gravity, resulting in the longest defrosting time in the bottom area. The upper part of the fins defrosts quickly and has a high temperature, while the bottom defrosts slowly and has a low temperature. Each time, it is necessary to wait until the bottom is defrosted cleanly before exiting the defrosting process. The defrosting time is long and the energy consumption is high.

[0005] 3. Affected by the serious frosting in the bottom area of the fins and the lowest defrosting temperature, the chassis and drainage grooves supporting the fins will also have the failure that the drainage is easily frozen, resulting in abnormal drainage.

[0006] At present, the following main measures are taken to solve the problem: A one-way valve is added to the bottom flow path of the finned heat exchanger. During heating, the refrigerant does not flow through the bottom flow path, so that the bottom area will not frost, and it can also be defrosted quickly during defrosting, avoiding ice accumulation at the bottom, and the defrosting energy consumption is reduced to a certain extent. This is a reliable measure. However, the disadvantage of this measure is that an additional one-way valve component is required, and the heat transfer area of the finned heat exchanger cannot be fully utilized. Content of the Utility Model

[0007] The technical problem to be solved by the utility model is how to optimize the structure of the finned heat exchanger, reduce the frosting degree and probability at the bottom of the finned heat exchanger, shorten the defrosting time and reduce the defrosting energy consumption.

[0008] To solve the above problems, the utility model provides a finned heat exchanger for an air energy heat pump, which is characterized by including fins, a subcooling inlet pipe, a subcooling outlet pipe, a flow dividing head, a liquid separating capillary tube, and a gas collecting pipe. The subcooling outlet pipe is connected to the flow dividing head; the bottom flow paths of the fins are all in an "S" shape, and the upper flow paths of the fins are all in an "n" shape.

[0009] The finned heat exchanger for an air source heat pump is characterized in that the subcooling inlet pipe and the subcooling outlet pipe are located at the bottom of the fins and are used to increase the temperature of the bottom area of the fins in the heating mode.

[0010] The finned heat exchanger for an air source heat pump is characterized in that the flow path at the bottom of a single fin is longer than the upper flow path of a single fin.

[0011] The finned heat exchanger for an air source heat pump is characterized in that the liquid distribution capillary at the bottom of the fins is shorter and has a larger inner diameter than the liquid distribution capillary of the upper flow path.

[0012] The finned heat exchanger for an air source heat pump is characterized in that in the heating mode, the low-temperature liquid refrigerant enters from the subcooling inlet pipe at the bottom of the fins, comes out from the subcooling outlet pipe, and flows into the flow dividing head.

[0013] The finned heat exchanger for an air source heat pump is characterized in that in the defrosting mode, the high-temperature gaseous refrigerant first exchanges heat with the frost and ice on the outermost bottom of the fin heat exchanger.

[0014] The finned heat exchanger for an air source heat pump is characterized in that in the defrosting mode, the refrigerants flowing out of all the flow paths of the fins converge to the flow dividing head. After the high-temperature refrigerant in the upper flow path of the fins is mixed with the medium-low temperature refrigerant at the bottom of the fins, when entering and leaving the subcooling pipe at the bottom of the fins, the flow rate and temperature of the flow path at the bottom of the fins are increased.

[0015] Implementing the present utility model has the following beneficial effects: The flow path and the liquid distribution head of the finned heat exchanger are adjusted and optimized for the above problems. During heating, the flow rate of the flow path at the bottom of the fins is increased, the temperature of the bottom area of the fins is increased, and the frosting degree of the bottom area of the fins is reduced. During defrosting, the flow rate and temperature of the flow path at the bottom of the fins are increased, and the frost at the bottom and the ice water flowing down from the upper part are quickly removed completely, avoiding icing at the bottom. During the defrosting process, the overall temperature and heat distribution of the fins are rationally allocated, the heat is fully utilized, the defrosting time is shortened, and the defrosting energy consumption is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic structural diagram of the finned heat exchanger of the present utility model;

[0017] Figure 2 is a schematic diagram of the composition of the flow dividing head. DETAILED DESCRIPTION OF THE INVENTION

[0018] The following will clearly and completely describe the technical solutions in the embodiments of the present utility model with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0019] The present utility model provides a finned heat exchanger and its flow path components that can be applied. The flow path and the liquid distributor of the finned heat exchanger are specifically adjusted and optimized for the defrosting problem. During heating, the liquid refrigerant does not throttle and depressurize again through the flow distributor and the liquid distribution capillary tube, so the temperature and pressure are slightly higher. When passing through the subcooling tube at the bottom of the fins, the temperature of the bottom area of the fins is increased, thereby slowing down and reducing the frosting in the bottom area of the fins. During defrosting, the refrigerant flowing out of all the flow paths of the fins converges to the flow distributor. Especially after the high-temperature refrigerant in the upper flow path of the fins is mixed with the medium-low temperature refrigerant at the bottom of the fins, when passing through the subcooling tube at the bottom of the fins, the flow rate and temperature of the bottom flow path of the fins are increased, and the frost at the bottom and the ice and water flowing down from the upper part are quickly removed, avoiding icing at the bottom. During the defrosting process, the heat of the fins is reasonably distributed, the heat of the upper flow path of the fins is fully utilized, the defrosting time is shortened, and the defrosting energy consumption is reduced. During defrosting, most of the frost layer is on the outer side of the fins. The hottest refrigerant in the bottom flow path preferentially enters the outer side of the finned heat exchanger and exits from the upper part of the flow path in an "S" shape. And because the liquid distribution capillary tube in the bottom flow path is shorter and has a larger inner diameter than that in the upper flow path, the flow rate is larger and the heat is also larger, melting the most serious frost layer and ice on the outer side, quickly removing the frost at the bottom and the ice and water flowing down from the upper part, fully utilizing the heat, reducing the defrosting time, avoiding icing at the bottom, and improving the defrosting effect. This finned heat exchanger does not need to use a check valve, fully utilizes the heat exchange area of the finned heat exchanger, and has a lower cost. The frosting degree of the finned heat exchanger is reduced, the defrosting is faster and more thorough, the number of defrosting times is reduced, the overall energy efficiency of the unit is higher, which is of great significance for energy conservation and emission reduction.

[0020] Figure 1 It is a schematic structural diagram of the finned heat exchanger of the present utility model. Figure 2It is a schematic diagram of the composition of the liquid distributor. The finned heat exchanger body 100: consists of multiple fins, and the fins are connected by copper pipes or similar materials to improve the heat exchange efficiency; the subcooling inlet pipe 102: is located at the bottom of the finned heat exchanger, and the low-temperature liquid refrigerant enters the heat exchanger from here. Its design helps to maintain the subcooled state of the refrigerant and improve the heat exchange efficiency; the subcooling outlet pipe 103: cooperates with the subcooling inlet pipe to allow the refrigerant heated by the fins to flow out and be ready to enter the flow distributor; the flow distributor 104: receives the refrigerant from the subcooling outlet pipe and evenly distributes it to each liquid distribution capillary; the liquid distribution capillary 105: connects the flow distributor and the fins and is responsible for evenly distributing the refrigerant to each flow path of the heat exchanger. Among them, the liquid distribution capillary at the bottom flow path is designed to be shorter and have a larger inner diameter to increase the flow rate; the gas collecting pipe 106: collects the gaseous refrigerant flowing out of the finned heat exchanger and guides it back to the heat pump system for circulation.

[0021] A specific implementation connection example is as follows: The low-temperature liquid refrigerant enters the subcooling inlet pipe 102 from the heat pump system, then flows out through the subcooling outlet pipe 103 and enters the flow distributor 104; the flow distributor 104 evenly distributes the refrigerant to each liquid distribution capillary 105, and then flows to each flow path of the finned heat exchanger.

[0022] It mainly includes a heating mode, a cooling mode, and a defrosting mode. Its working principle is:

[0023] Heating mode:

[0024] 1. The low-temperature liquid refrigerant enters the bottom of the fins through a specially designed subcooling inlet pipe. This inlet pipe design helps to increase the temperature of the bottom area and slow down frosting.

[0025] 2. The refrigerant does not go through the throttling and pressure reduction of the flow distributor and the liquid distribution capillary, maintains a relatively high temperature and pressure, and directly enters the flow distributor.

[0026] 3. The flow distributor evenly distributes the refrigerant to each flow path of the finned heat exchanger. Among them, the upper flow path is designed as an "n" shape, and the bottom flow path is designed as an "S" shape to achieve more efficient heat exchange.

[0027] 4. The refrigerant exchanges heat with the air in the fins, evaporates into a gas state, and then is collected by the gas collecting pipe and returned to the heat pump system.

[0028] Cooling mode

[0029] 1. The high-temperature gaseous refrigerant is distributed from the gas collecting pipe to each flow path of the finned heat exchanger. The flow path enters from the air outlet side and exits from the air inlet side.

[0030] 2. The upper flow path and the bottom flow path are respectively designed as an "n" shape and an "S" shape to optimize the heat exchange between the air and the refrigerant.

[0031] 3. The gaseous refrigerant condenses and releases heat in the fins, heating the air, and then turns into a medium- and low-temperature liquid refrigerant.

[0032] 4. After flowing out, the refrigerant converges into the liquid distributor and is further subcooled through the subcooling inlet pipe and the subcooling outlet pipe to improve the refrigeration efficiency of the system.

[0033] Defrosting mode:

[0034] 1. The high-temperature gaseous refrigerant is distributed from the header pipe to each flow path of the finned heat exchanger. The flow path enters from the air outlet side and exits from the air inlet side to achieve reverse heat exchange.

[0035] 2. The bottom flow path is specially designed to receive more high-temperature gaseous refrigerant, giving priority to heat exchange with the frost and ice at the bottom of the outermost side of the fins to accelerate the melting of the frost and ice.

[0036] 3. The liquid distribution capillary of the bottom flow path is designed to be shorter and have a larger inner diameter, providing a larger flow rate and heat to quickly melt the most serious frost layer and ice on the outside.

[0037] 4. During the defrosting process, the high-temperature refrigerant in the upper flow path of the fins is mixed with the medium- and low-temperature refrigerant in the bottom flow path to increase the temperature and flow rate of the bottom flow path of the fins and achieve rapid defrosting.

[0038] 5. The melted water flows to the bottom through the optimized drainage structure, avoiding the icing problem caused by poor drainage.

[0039] Through the optimization of the flow path design, the following effects are achieved:

[0040] 1. The length and inner diameter of the liquid distribution capillary are carefully designed to achieve the refrigerant distribution ratio of different flow paths and optimize the heating and defrosting effects.

[0041] 2. The shape and path of the flow path are designed considering the flow characteristics of the refrigerant and the heat exchange efficiency. Especially the application of the "S"-shaped flow path in the defrosting mode to achieve more uniform and efficient frost layer melting.

[0042] 3. The design of the flow path allows the refrigerant to form specific flow patterns in the fins, such as "n"-shaped and "S"-shaped, to increase the heat exchange area and efficiency.

[0043] At the same time, through the optimization of the structure design, the following effects are achieved:

[0044] 1. The pitch and shape of the fins are optimized to reduce the air flow resistance, improve the heat exchange efficiency, and reduce the possibility of frosting at the same time.

[0045] 2. The position and design of the subcooling inlet pipe and the subcooling outlet pipe take into account the flow and temperature control of the refrigerant to achieve better heating effect.

[0046] 3. The design of the flow splitter allows the refrigerant to be evenly distributed to each flow path in different modes, improving the response speed and efficiency of the system.

[0047] The above disclosure is only one embodiment of the present utility model. Of course, it cannot be used to limit the scope of the rights of the present utility model. Those of ordinary skill in the art can understand and implement all or part of the above-mentioned embodiments, and the equivalent changes made according to the claims of the present utility model still fall within the scope covered by the utility model.

Claims

1. A finned heat exchanger for an air energy heat pump, characterized in that It includes fins, subcooling inlet pipes, subcooling outlet pipes, splitter heads, liquid separation capillaries and gas collecting pipes. The subcooling outlet pipes are connected to the splitter heads. The flow paths at the bottom of the fins are all in an "S" shape, and the flow paths at the top are all in an "n" shape.

2. The finned heat exchanger for an air energy heat pump according to claim 1, characterized in that: The subcooling inlet pipe and the subcooling outlet pipe are located at the bottom of the fins and are used to increase the temperature of the bottom area of ​​the fins in the heating mode.

3. The finned heat exchanger for air energy heat pump according to claim 2 is characterized in that The bottom flow path of a single fin is longer than the upper flow path of a single fin.

4. The finned heat exchanger for an air energy heat pump according to claim 3 is characterized in that The liquid separation capillary of the bottom flow path of the fin is shorter and has a larger inner diameter than the liquid separation capillary of the upper flow path.

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