A mixed working fluid heat pump system and control method based on residual pressure driven mixed matrix membrane.

Abstract

This invention discloses a mixed working fluid heat pump system and control method based on a residual pressure-driven mixed matrix membrane. The system includes a mixed working fluid heat pump system and a component regulation device. The mixed working fluid heat pump system includes a compressor, a condenser, a throttling valve I, and an evaporator. The component regulation device includes a three-way valve I, a working fluid separator, a component one storage tank, a throttling valve II, a three-way valve II, a component two storage tank, a throttling valve III, and a three-way valve III. The working fluid separator includes a mixed matrix membrane and a microporous membrane. The component regulation device is connected to the refrigerant circuit of the heat pump system. This system can change the concentration of the mixed working fluid components during system operation without charging or discharging refrigerant, solving the problem that mixed working fluid heat pumps are only suitable for specific operating conditions. It can flexibly adjust the working fluid component concentration according to different operating conditions, expanding the application scenarios of mixed working fluid heat pumps.

Description

Technical Field

[0001] This invention belongs to the field of mixed working fluid heat pumps, and relates to a mixed working fluid heat pump system and control method based on residual pressure driving a mixed matrix membrane. Background Technology

[0002] A heat pump is a device that can efficiently transfer heat and has a wide range of applications in industrial, agricultural, commercial, and residential heating, cooling, and dehumidification fields.

[0003] The working fluid of a heat pump largely determines its performance and energy efficiency. With the iterative development of refrigerants, more and more are being phased out due to their environmental pollution. While developing new natural and synthetic refrigerants, mixed refrigerants are increasingly attracting the interest of scholars worldwide. In particular, non-azeotropic mixed working fluids are being widely studied and applied because their temperature glide during phase change can improve the temperature matching of heat exchangers.

[0004] However, a significant drawback of non-azeotropic refrigerant mixtures is their complex charging process. The component concentration of a non-azeotropic refrigerant mixture determines its temperature glide, which in turn determines its applicable operating conditions. In practical applications, heat pumps often face various operating conditions. If the system's operating conditions change, the optimal component concentration of the refrigerant mixture will often change as well. In such cases, to maintain efficient operation, it is necessary to drain and recharge the refrigerant, which significantly limits the application of non-azeotropic refrigerant mixtures. Summary of the Invention

[0005] Purpose of the invention: This invention provides a mixed working fluid heat pump system and control method based on residual pressure driven mixed matrix membrane, which can adjust the component concentration of the system during operation without recharging the refrigerant, thereby adapting to various operating conditions and enabling the system to maintain high efficiency under various conditions.

[0006] Technical solution: To solve the above technical problems, the present invention adopts the following technical solution:

[0007] A mixed working fluid heat pump system based on residual pressure driving a mixed matrix membrane includes a mixed working fluid heat pump system and a component control device;

[0008] The mixed working fluid heat pump system includes a compressor, a condenser, a throttle valve I, and an evaporator;

[0009] The component control device includes a three-way valve I, a working fluid separator, a component one storage tank, a throttle valve II, a three-way valve II, a component two storage tank, a throttle valve III, and a three-way valve III.

[0010] The compressor outlet is connected to the condenser inlet, the condenser outlet is connected to the inlet of three-way valve I, the three-way valve I outlet is connected to the inlet of throttle valve I, the throttle valve I outlet is connected to the inlet of three-way valve II, the three-way valve II outlet is connected to the inlet of three-way valve III, the three-way valve III outlet is connected to the evaporator inlet, and the evaporator outlet is connected to the compressor inlet.

[0011] The bypass port of the three-way valve I is connected to the inlet end of the working fluid separator, the first outlet end of the working fluid separator is connected to the inlet end of the component one storage tank, the outlet end of the component one storage tank is connected to the inlet end of the throttle valve II, and the outlet end of the throttle valve II is connected to the bypass port of the three-way valve II.

[0012] The second outlet end of the working fluid separator is connected to the inlet end of the component two storage tank, the outlet end of the component two storage tank is connected to the inlet end of the throttle valve III, and the outlet end of the throttle valve III is connected to the bypass port of the three-way valve III.

[0013] A carbon dioxide / methane working fluid flows through the system via pipelines.

[0014] Furthermore, the working fluid separator includes a mixing matrix membrane and a microporous membrane;

[0015] The hybrid matrix membrane is made by incorporating zeolite molecules into a polymer matrix (PA). It has high permeability to methane and low permeability to carbon dioxide. Zeolite is an aluminosilicate mineral with a regular pore structure. The polymer matrix (PA) refers to a polyamide carrier.

[0016] The microporous membrane is a porous thin film material with a large number of micropores. The surface layer of the microporous membrane is usually very thin with small pore size, which helps to achieve efficient filtration. Its pore size is controlled so that carbon dioxide can pass through easily while methane cannot. Therefore, it has high carbon dioxide permeability and low methane permeability. Below the surface layer, there may be one or more support layers that provide mechanical strength. These layers typically have larger pore sizes to reduce resistance to fluid flow.

[0017] The above-mentioned control method for a mixed working fluid heat pump system based on residual pressure-driven mixed matrix membrane,

[0018] After being compressed by the compressor, the mixed working fluid enters the condenser for condensation. Then, when it flows through the three-way valve I, part of the working fluid enters the throttle valve I from the outlet of the three-way valve I, and part of the working fluid flows into the working fluid separator from the bypass port of the three-way valve I.

[0019] After the mixed working fluid enters the working fluid separator, methane passes through the mixed matrix membrane and enters the component one storage tank from the first outlet end, while carbon dioxide passes through the microporous membrane and enters the component two storage tank from the second outlet end. The mixed working fluid is separated in the working fluid separator.

[0020] The methane in the storage tank of component one is insulated and throttled by throttle valve II before entering the bypass port of three-way valve II.

[0021] The carbon dioxide in the component two storage tank enters the bypass port of the three-way valve III after being thermally throttled by the throttle valve III.

[0022] The working fluid enters the throttling valve I and is adiabatically throttled. Then, it mixes with the methane flowing in through the bypass port of the three-way valve II and enters the three-way valve III. After mixing with the carbon dioxide flowing in through the bypass port of the three-way valve III, it enters the evaporator and evaporates to a gaseous state before entering the compressor for compression to achieve system circulation.

[0023] Furthermore, the bypass port opening of the three-way valve I controls the proportion of the working fluid flowing into the component regulating device within the heat pump system; the bypass port openings of the throttle valve II and the three-way valve II control the methane flow rate distributed back to the heat pump system by the component regulating device; and the bypass port openings of the throttle valve III and the three-way valve III control the carbon dioxide flow rate distributed back to the heat pump system by the component regulating device.

[0024] During steady-state operation of the system, the proportion of methane and carbon dioxide distributed back to the heat pump system by the component control device is the same as the proportion flowing into the component control device from the heat pump system. Component tank 1 and component tank 2 store a certain amount of methane and carbon dioxide.

[0025] When it is necessary to change the system component concentration (such as increasing the methane concentration), increase the bypass opening of throttle valve II and three-way valve II or decrease the bypass opening of throttle valve III and three-way valve III. The proportion of methane distributed back to the heat pump system by the component control device increases, and more methane flows out of component one storage tank. When the system reaches three-way valve I, part of this extra methane flows back to component one storage tank through the working fluid separator, and part circulates in the heat pump system through throttle valve I. Overall, the methane storage in component one storage tank decreases until the system reaches steady state again, and the proportion of methane in the heat pump system increases.

[0026] When it is necessary to increase the carbon dioxide concentration, increase the opening of the bypass port of throttle valve III and three-way valve III or decrease the opening of the bypass port of throttle valve II and three-way valve II. The proportion of carbon dioxide distributed back to the heat pump system by the component control device increases, and more carbon dioxide flows out of the component II storage tank. When the system runs to three-way valve I, part of this extra carbon dioxide flows back to the component II storage tank through the working fluid separator, and part circulates in the heat pump system through throttle valve I. Overall, the carbon dioxide storage in the component II storage tank decreases until the system reaches steady state again, and the proportion of carbon dioxide in the heat pump system increases.

[0027] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0028] (1) Flexible response to different working conditions

[0029] Under different operating conditions, the heat exchanger corresponds to different temperature glide requirements. By adjusting the component concentration during system operation, the system can maintain high energy efficiency under different operating conditions, and the adjustment process does not require recharging, which is quite flexible.

[0030] (2) Reduce the impact of leakage

[0031] Since the system's component concentration is adjustable, minor leaks during long-term use of a mixed working fluid heat pump will not have a significant impact on energy efficiency.

[0032] (3) The mixed working fluid component separation membrane uses the residual pressure of the compressor exhaust as the driving force, and the component control system has no additional power consumption. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the system structure of the present invention.

[0034] The diagram shows: 1-compressor, 2-condenser, 3-throttle valve I, 4-evaporator, 5-component control device, 6-three-way valve I, 7-working fluid separator, 8-component I storage tank, 9-throttle valve II, 10-three-way valve II, 11-component II storage tank, 12-throttle valve III, 13-three-way valve III, 14-mixing matrix membrane, 15-microporous membrane. Detailed Implementation

[0035] The technical solution of the present invention will be further described below with reference to the embodiments and accompanying drawings. The following examples or drawings are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0036] like Figure 1 As shown, a mixed working fluid heat pump system based on residual pressure driven mixed matrix membrane includes a mixed working fluid heat pump system and a component control device 5.

[0037] The mixed working fluid heat pump system includes a compressor 1, a condenser 2, a throttling valve I 3, and an evaporator 4;

[0038] The component control device 5 includes a three-way valve I 6, a working fluid separator 7, a component one storage tank 8, a throttle valve II 9, a three-way valve II 10, a component two storage tank 11, a throttle valve III 12, and a three-way valve III 13;

[0039] The outlet end of the compressor 1 is connected to the inlet end of the condenser 2, the outlet end of the condenser 2 is connected to the inlet end of the three-way valve I6, the outlet end of the three-way valve I6 is connected to the inlet end of the throttle valve I3, the outlet end of the throttle valve I3 is connected to the inlet end of the three-way valve II10, the outlet end of the three-way valve II10 is connected to the inlet end of the three-way valve III13, the outlet end of the three-way valve III13 is connected to the inlet end of the evaporator 4, and the outlet end of the evaporator 4 is connected to the inlet end of the compressor 1.

[0040] The bypass port of the three-way valve I6 is connected to the inlet end of the working fluid separator 7, the first outlet end of the working fluid separator 7 is connected to the inlet end of the component storage tank 8, the outlet end of the component storage tank 8 is connected to the inlet end of the throttle valve II9, and the outlet end of the throttle valve II9 is ​​connected to the bypass port of the three-way valve II10.

[0041] The second outlet end of the working fluid separator 7 is connected to the inlet end of the component two storage tank 11, the outlet end of the component two storage tank 11 is connected to the inlet end of the throttle valve III 12, and the outlet end of the throttle valve III 12 is connected to the bypass port of the three-way valve III 13.

[0042] A carbon dioxide / methane working fluid flows through the system via pipelines.

[0043] The working fluid separator 7 includes a mixing matrix membrane 14 and a microporous membrane 15;

[0044] The mixed matrix membrane 14 is made by incorporating zeolite molecules into a polymer matrix. It has high permeability to methane and low permeability to carbon dioxide. Zeolite is an aluminosilicate mineral with a regular pore structure. The polymer matrix (PA) refers to a polyamide carrier.

[0045] The microporous membrane 15 is a porous thin film material with micropores. The surface layer of the microporous membrane is typically very thin with small pore size, which helps to achieve efficient filtration. Its pore size is controlled so that carbon dioxide can pass through easily while methane cannot. Therefore, it has high carbon dioxide permeability and low methane permeability. Below the surface layer, there may be one or more support layers that provide mechanical strength. These layers typically have larger pore sizes to reduce resistance to fluid flow.

[0046] In the above-mentioned control method of the mixed working fluid heat pump system based on residual pressure driving mixed matrix membrane, the mixed working fluid is compressed by the compressor 1 and then condensed in the condenser 2. When it flows through the three-way valve I6, part of the working fluid enters the throttle valve I3 from the outlet of the three-way valve I6, and part of the working fluid flows into the working fluid separator 7 from the bypass port of the three-way valve I6.

[0047] After the mixed working fluid enters the working fluid separator 7, the methane passes through the mixed matrix membrane 14 and enters the component one storage tank 8 from the first outlet end, while the carbon dioxide passes through the microporous membrane 15 and enters the component two storage tank 11 from the second outlet end. The mixed working fluid is separated in the working fluid separator 7.

[0048] The methane in the first component storage tank 8 is throttled by the throttle valve II9 and then enters the bypass port of the three-way valve II10.

[0049] The carbon dioxide in the component two storage tank 11 is throttled by the throttle valve Ⅲ12 and then enters the bypass port of the three-way valve Ⅲ(12).

[0050] The working fluid enters the throttle valve I3 and is adiabatically throttled. Then, it mixes with the methane flowing in through the bypass port of the three-way valve II10 via the three-way valve 10 and enters the three-way valve III13. After mixing with the carbon dioxide flowing in through the bypass port of the three-way valve III13, it enters the evaporator 4 and evaporates to a gaseous state before entering the compressor 1 for compression to achieve system circulation.

[0051] The bypass opening of the three-way valve I6 controls the proportion of the working fluid flowing into the component regulating device 5 in the heat pump system; the bypass openings of the throttle valve II9 and the three-way valve II10 control the methane flow rate distributed back to the heat pump system by the component regulating device 5; the bypass openings of the throttle valve III12 and the three-way valve III13 control the carbon dioxide flow rate distributed back to the heat pump system by the component regulating device 5.

[0052] During steady-state operation of the system, the ratio of methane and carbon dioxide distributed back to the heat pump system by the component control device 5 is the same as the ratio of methane and carbon dioxide flowing into the component control device 5 from the heat pump system. Component 1 storage tank 8 and Component 2 storage tank 11 store methane and carbon dioxide.

[0053] When it is necessary to increase the methane concentration, increase the bypass opening of throttle valve II9 and three-way valve II10 or decrease the bypass opening of throttle valve III12 and three-way valve III13. The proportion of methane distributed back to the heat pump system by component control device 5 increases, and more methane flows out of component one storage tank 8. When the system runs to three-way valve I6, part of the extra methane flows back to component one storage tank 8 through working fluid separator 7, and part of it circulates in the heat pump system through throttle valve I3. Overall, the methane storage in component one storage tank 8 decreases until the system reaches steady state again, and the proportion of methane in the heat pump system increases.

[0054] When it is necessary to increase the carbon dioxide concentration, the bypass opening of throttle valve III12 and three-way valve III13 is increased, or the bypass opening of throttle valve II9 and three-way valve II10 is decreased. The proportion of carbon dioxide distributed back to the heat pump system by component control device 5 increases, and the amount of carbon dioxide flowing out of component two storage tank 11 increases. When the system runs to three-way valve I6, part of this extra carbon dioxide flows back to component two storage tank 11 through working fluid separator 7, and part circulates in the heat pump system through throttle valve I3. Overall, the carbon dioxide storage in component two storage tank 11 decreases until the system reaches steady state again, and the proportion of carbon dioxide in the heat pump system increases.

[0055] The above embodiments are merely illustrative of the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solutions based on the technical concept proposed in this invention shall fall within the scope of protection of this invention.

Claims

1. A mixed working fluid heat pump system based on residual pressure-driven mixed matrix membrane, characterized in that, Includes a mixed working fluid heat pump system and a component control device (5); The mixed working fluid heat pump system includes a compressor (1), a condenser (2), a throttle valve I (3), and an evaporator (4); The component control device (5) includes a three-way valve I (6), a working fluid separator (7), a component one storage tank (8), a throttle valve II (9), a three-way valve II (10), a component two storage tank (11), a throttle valve III (12), and a three-way valve III (13); The outlet end of the compressor (1) is connected to the inlet end of the condenser (2), the outlet end of the condenser (2) is connected to the inlet end of the three-way valve I (6), the outlet end of the three-way valve I (6) is connected to the inlet end of the throttle valve I (3), the outlet end of the throttle valve I (3) is connected to the inlet end of the three-way valve II (10), the outlet end of the three-way valve II (10) is connected to the inlet end of the three-way valve III (13), the outlet end of the three-way valve III (13) is connected to the inlet end of the evaporator (4), and the outlet end of the evaporator (4) is connected to the inlet end of the compressor (1). The bypass port of the three-way valve I (6) is connected to the inlet end of the working fluid separator (7), the first outlet end of the working fluid separator (7) is connected to the inlet end of the component storage tank (8), the outlet end of the component storage tank (8) is connected to the inlet end of the throttle valve II (9), and the outlet end of the throttle valve II (9) is connected to the bypass port of the three-way valve II (10). The second outlet end of the working fluid separator (7) is connected to the inlet end of the component two storage tank (11), the outlet end of the component two storage tank (11) is connected to the inlet end of the throttle valve III (12), and the outlet end of the throttle valve III (12) is connected to the bypass port of the three-way valve III (13). A carbon dioxide / methane working fluid flows through the system via pipelines.

2. The mixed working fluid heat pump system based on residual pressure driven mixed matrix membrane according to claim 1, characterized in that, The working fluid separator (7) includes a mixing matrix membrane (14) and a microporous membrane (15); The mixed matrix membrane (14) is made by incorporating zeolite molecules into a polymer matrix. Zeolite is an aluminosilicate mineral with a regular pore structure, and the polymer matrix refers to a polyamide carrier. The microporous membrane (15) is a porous thin film material with micropores.

3. The control method for a mixed working fluid heat pump system based on residual pressure driven mixed matrix membrane according to claim 1 or 2, characterized in that, After being compressed by the compressor (1), the mixed working fluid enters the condenser (2) for condensation. Then, when it flows through the three-way valve I (6), part of the working fluid enters the throttle valve I (3) from the outlet of the three-way valve I (6), and part of the working fluid flows into the working fluid separator (7) from the bypass port of the three-way valve I (6). After the mixed working fluid enters the working fluid separator (7), the methane passes through the mixed matrix membrane (14) and enters the component one storage tank (8) from the first outlet end, while the carbon dioxide passes through the microporous membrane (15) and enters the component two storage tank (11) from the second outlet end. The mixed working fluid is separated in the working fluid separator (7). The methane in the first component storage tank (8) is adiabatically throttled by the throttle valve II (9) and then enters the bypass port of the three-way valve II (10); The carbon dioxide in the component two storage tank (11) is insulated and throttled by the throttle valve III (12) and then enters the bypass port of the three-way valve III (12); The working fluid enters the throttle valve I (3) and is adiabatically throttled. Then it mixes with the methane flowing in through the bypass port of the three-way valve II (10) and enters the three-way valve III (13). After mixing with the carbon dioxide flowing in through the bypass port of the three-way valve III (13), it enters the evaporator (4) and evaporates to a gaseous state before entering the compressor (1) for compression to achieve system circulation.

4. The control method for a mixed working fluid heat pump system based on residual pressure-driven mixed matrix membrane according to claim 3, characterized in that... The opening degree of the bypass port of the three-way valve I (6) controls the proportion of the working fluid flowing into the component regulating device (5) in the heat pump system; The bypass port opening of throttle valve II (9) and three-way valve II (10) controls the component regulation device (5) to distribute the methane flow of the regenerative pump system; The bypass port opening control component regulation device (5) of the throttle valve III (12) and the three-way valve III (13) distributes the carbon dioxide flow of the heat pump system; When the system is in steady state, the ratio of methane and carbon dioxide distributed by the component control device (5) to the heat pump system is the same as the ratio of methane and carbon dioxide flowing into the component control device (5) from the heat pump system. Component 1 storage tank (8) and Component 2 storage tank (11) store methane and carbon dioxide. When it is necessary to increase the methane concentration, increase the opening of the bypass port of throttle valve II (9) and three-way valve II (10) or decrease the opening of the bypass port of throttle valve III (12) and three-way valve III (13). The proportion of methane distributed back to the heat pump system by the component control device (5) increases, and the amount of methane flowing out of component tank 1 (8) increases. When the system runs to three-way valve I (6), part of the extra methane flows back to component tank 1 (8) through the working fluid separator (7), and part of it circulates in the heat pump system through throttle valve I (3). Overall, the amount of methane stored in component tank 1 (8) decreases until the system reaches steady state again, and the proportion of methane in the heat pump system increases. When it is necessary to increase the carbon dioxide concentration, increase the opening of the bypass port of throttle valve III (12) and three-way valve III (13) or decrease the opening of the bypass port of throttle valve II (9) and three-way valve II (10). The proportion of carbon dioxide distributed back to the heat pump system by the component control device (5) increases, and the amount of carbon dioxide flowing out of the component two storage tank (11) increases. When the system runs to the three-way valve I (6), part of the extra carbon dioxide flows back to the component two storage tank (11) through the working fluid separator (7), and part of it circulates in the heat pump system through the throttle valve I (3). Overall, the carbon dioxide storage in the component two storage tank (11) decreases until the system reaches a steady state again, and the proportion of carbon dioxide in the heat pump system increases.

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