Electric compression type-absorption type heat pump unit of coupling plate type evaporator
The electric compression-absorption heat pump unit with coupled plate evaporator solves the problem of difficult utilization of low-temperature heat sources, achieves efficient heat extraction and cost reduction, improves heat transfer coefficient, and makes the equipment more compact.
Patent Information
- Application Number
- CN202520333875.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-27
- Publication Date
- 2026-01-13
- Estimated Expiration
- 2035-02-27
AI Technical Summary
In existing technologies, it is difficult to utilize low-temperature heat sources. Traditional shell-and-tube evaporators have low heat exchange efficiency, large size, and high cost, and require intermediate circulating water pumps, which increase power consumption and operating costs.
The electric compression-absorption heat pump unit, which uses a coupled plate evaporator, eliminates the intermediate circulating water and directly realizes the condensation of electric heat pump refrigerant and the evaporation of absorption heat pump refrigerant in the absorption heat pump evaporator. The plate rising film evaporator is used to improve the heat exchange efficiency.
It improves the heat extraction efficiency of low-temperature heat sources, reduces equipment costs and operating costs, increases the heat transfer coefficient by more than two times, is more compact, and is simple and convenient to process.
Smart Images
Figure CN223795515U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of waste heat recovery technology, and in particular to an electric compression-absorption heat pump unit with a coupled plate evaporator. Background Technology
[0002] Currently, in the field of waste heat recovery heating, there are many low-temperature heat sources, such as extracting heat from the soil using buried pipes. The temperature difference between the low-temperature heat source and the area to be heated is large, so absorption heat pumps cannot be used directly to raise the temperature. The outlet temperature of the hot water side of conventional electric heat pumps cannot meet the heating demand. Therefore, a combined operation of electric and absorption heat pumps is considered to achieve the goal. The general solution is to set up a circulating water and circulating pump between the condenser of the electric heat pump and the evaporator of the absorption heat pump. The circulating water absorbs heat in the condenser of the electric heat pump and then releases heat in the evaporator of the absorption heat pump. However, this method has three main problems: First, it loses the heat transfer temperature difference, reduces the temperature of the circulating water entering the evaporator of the absorption heat pump and the evaporation temperature, and increases the cost of the absorption heat pump. Second, the circulating water pump increases power consumption and operating costs. Third, the electric heat pump also needs to be equipped with a condenser, which is generally a shell-and-tube structure, which is costly and occupies a large area.
[0003] Currently, evaporators in various types of electric compression chillers / heat pumps and absorption chillers / heat pumps generally adopt a shell-and-tube structure. The refrigerant evaporates outside the tubes using either submersion or falling film evaporation, while the low-temperature heat source (usually water, steam, or other working fluid) flows inside the tubes. Some electric compression chillers also use dry evaporators, where the refrigerant evaporates inside the tubes and the low-temperature heat source flows outside. Due to limitations in the physical properties, flow velocity, and resistance requirements of the media on both sides, the heat transfer coefficient of this type of shell-and-tube heat exchanger is relatively low. To improve the heat transfer coefficient, special processing is required on the inner and outer sides of the heat transfer tubes to enhance heat exchange. Therefore, this type of heat exchanger is generally large in size, requires a large amount of metal for the outer shell, has high heat transfer tube costs, and requires a large refrigerant filling volume. Furthermore, this type of shell-and-tube heat exchanger is generally a fixed tube sheet structure, requiring the heat transfer tubes to be connected to the tube sheet by welding, expansion joints, or a combination of both. For these reasons, traditional shell-and-tube evaporators have low heat exchange efficiency, large size, high cost, and are difficult to manufacture.
[0004] Based on this, the present invention provides a plate evaporator and an electric compression-absorption heat pump unit with coupled plate evaporator that can improve heat exchange efficiency. Utility Model Content
[0005] The purpose of this utility model is to provide an electric compression-absorption heat pump unit with a coupled plate evaporator. This heat pump unit can effectively extract heat from a low-temperature heat source to heat a medium-temperature heat source, and has high heat exchange efficiency.
[0006] This utility model provides an electric compression-absorption heat pump unit with a coupled plate evaporator, including an electric heat pump evaporator, a compressor, an absorption heat pump absorber, an absorption heat pump evaporator, an absorption heat pump generator, an absorption heat pump condenser, and a solution heat exchanger; the electric heat pump evaporator and the absorption heat pump evaporator have the same structure, both being plate rising film evaporators. The evaporator includes a shell, and a pair of heat exchange plates are provided inside the shell. The pair of heat exchange plates has a heat source inlet and a heat source outlet. Refrigerant is provided between the shell and the pair of heat exchange plates. A refrigerant vapor outlet is provided at the top of the shell, and a liquid refrigerant inlet is provided at the bottom of the shell.
[0007] The electric heat pump evaporator's heat source inlet is connected to a low-temperature heat source. The electric heat pump evaporator's refrigerant vapor outlet is connected in sequence via pipes to the compressor, the absorption heat pump evaporator's heat source inlet, the absorption heat pump evaporator's heat source outlet, and the electric heat pump evaporator's liquid refrigerant inlet. The absorption heat pump evaporator's refrigerant vapor outlet is connected in sequence via pipes to the absorption heat pump absorber, the solution heat exchanger, the absorption heat pump generator, the absorption heat pump condenser, and the absorption heat pump evaporator's liquid refrigerant inlet. The absorption heat pump generator is connected in sequence via pipes to the solution heat exchanger and the absorption heat pump absorber. The medium to be heated is discharged after being heated by the absorption heat pump absorber and the absorption heat pump condenser through pipes. The absorption heat pump generator's inlet is connected to a driving heat source.
[0008] Preferably, multiple sets of heat exchange plate pairs are arranged in parallel inside the shell. Each set of heat exchange plate pairs has two upper and lower opposite interfaces on its upper side, and the interfaces are respectively connected to the heat source inlet and the heat source outlet.
[0009] Preferably, each heat exchange plate pair consists of two plates with a medium channel inside, and the two plates are connected around their perimeter by laser, resistance sealing welding or brazing.
[0010] Preferably, the housing is provided with a liquid-blocking device, which is located at the top of the housing and consists of several vertically arranged baffles. The refrigerant vapor outlet is located above the liquid-blocking device.
[0011] Preferably, a level gauge is provided inside the housing, and the refrigerant level in the evaporator is lower than the height of the heat exchange plate.
[0012] Preferably, the level gauge is one of the following: differential pressure level gauge, float level gauge, magnetic level gauge, tuning fork level gauge, and guided wave radar level gauge.
[0013] Preferably, a valve is provided on the liquid refrigerant inlet connection pipe.
[0014] Preferably, the valve is one of an electric valve, a solenoid valve, a float valve, or a thermostatic expansion valve.
[0015] Preferably, the refrigerant inside the evaporator housing of the electric heat pump is Freon.
[0016] Preferably, the refrigerant inside the evaporator shell of the absorption heat pump is water.
[0017] Beneficial effects:
[0018] This invention proposes an electric compression-absorption heat pump unit with a coupled plate evaporator, which can effectively extract heat from a low-temperature heat source to heat a medium-temperature heat source for heating. By setting up an electric heat pump evaporator and an absorption heat pump evaporator, the electric heat pump condenser is omitted, and the electric heat pump refrigerant condensation and absorption heat pump refrigerant evaporation effects are directly achieved in the absorption heat pump evaporator. It has high heat exchange efficiency, eliminates the need for intermediate circulating water in conventional solutions, and reduces heat loss, equipment cost, and operating costs.
[0019] This invention utilizes a plate-type rising film evaporator, combining the advantages of plate heat exchange surface condensation and boiling with rising film heat exchange. It offers excellent heat exchange performance. Tests in lithium bromide absorption heat pump evaporators show that its heat transfer coefficient is more than twice that of conventional shell-and-tube heat transfer tube structures, meaning the heat transfer area can be reduced by more than half. This saves on the amount of material used for heat exchange, allowing for a more compact and smaller evaporator. Furthermore, the processing and installation of this plate-type evaporator are simpler and more efficient, facilitating improved equipment production efficiency and reduced manufacturing costs. Moreover, compared to conventional electric compression chillers / heat pumps using shell-and-tube submerged evaporators, less refrigerant is required, saving refrigerant costs and contributing to environmental protection. Attached Figure Description
[0020] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0021] Figure 1 This is a schematic diagram of the overall structure of this utility model.
[0022] Explanation of reference numerals in the attached figures:
[0023] 1-Heat exchange plate pair, 2-Liquid baffle device, 3-Refrigerant vapor outlet, 4-Shell, 5-Heat source inlet, 6-Heat source outlet, 7-Level gauge, 8-Valve, 9-Liquid refrigerant inlet, 10-Electric heat pump evaporator, 11-Absorption heat pump evaporator, 12-Solution pump, A-Absorption heat pump absorber, C-Absorption heat pump condenser, G-Absorption heat pump generator, EX-Solution heat exchanger, COM-Compressor. Detailed Implementation
[0024] The technical solution of this utility model will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.
[0025] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.
[0026] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly; for example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0027] Example 1
[0028] like Figure 1As shown, an electric compression-absorption heat pump unit with coupled plate evaporators includes an electric heat pump evaporator 10, a compressor COM, an absorption heat pump absorber A, an absorption heat pump evaporator 11, an absorption heat pump generator G, an absorption heat pump condenser C, and a solution heat exchanger EX; the electric heat pump evaporator 10 and the absorption heat pump evaporator 11 have the same structure, both being plate rising film evaporators;
[0029] The evaporator includes a shell 4 made of metal. Multiple sets of heat exchange plates 1 are arranged in parallel inside the shell 4. Each set of heat exchange plates 1 consists of two plates with internal medium channels. The two plates are connected around their perimeter by laser, resistance sealing welding, or brazing. The plates have a herringbone, dotted, or corrugated structure to enhance heat exchange efficiency and mechanical strength. The plates are made of stainless steel or titanium. Each set of heat exchange plates 1 has two opposing interfaces on its upper side, connecting to a heat source inlet 5 and a heat source outlet 6, respectively. Refrigerant is placed between the shell 4 and the heat exchange plates 1. The refrigerant level inside the evaporator is lower than the height of the heat exchange plates 1, preferably half-submerged, to facilitate subsequent refrigerant evaporation and film formation. The specific refrigerant level can be determined through testing based on its physical properties, evaporation temperature, pressure, and other external conditions. A level gauge 7 is installed inside the shell 4 to detect the refrigerant level. The level gauge 7 adopts one of the following: differential pressure level gauge, float level gauge, magnetic level gauge, tuning fork level gauge, and guided wave radar level gauge.
[0030] The top of the housing 4 is provided with a refrigerant vapor outlet 3, the bottom of the housing 4 is provided with a liquid refrigerant inlet 9, and the inside of the housing 4 is provided with a liquid-blocking device 2. The liquid-blocking device 2 is located at the top of the housing 4 and is composed of several vertically arranged baffles. The baffles adopt herringbone, Z-shaped and other structures to increase the contact area between the baffles and the refrigerant vapor. The refrigerant vapor outlet 3 is located above the liquid-blocking device 2.
[0031] The heat source enters the heat exchange plate pair 1 through the heat source inlet 5. The refrigerant exchanges heat with the heat source through the heat exchange plate pair 1. After absorbing heat, the refrigerant droplets splashed in the boiling evaporation state rise to the plate positions not submerged by the refrigerant, forming a rising film wetted state. This liquid film continues to exchange heat with the heat source in the heat exchange plate pair 1 and is heated and evaporated into a vapor state. The refrigerant vapor rises to the top of the evaporator, and the droplets it carries adhere to the baffle plate to prevent the droplets from entering subsequent equipment. The refrigerant vapor with the droplets removed is discharged through the refrigerant vapor outlet 3 at the top of the liquid-blocking device 2 and enters the next process.
[0032] A valve 8 is installed on the liquid refrigerant inlet 9 connecting pipe. Valve 8 is one of the following: electric valve, solenoid valve, float valve, or thermostatic expansion valve. The refrigerant flow rate in the evaporator can be adjusted through valve 8, thereby controlling the refrigerant level in the evaporator. Valve 8, in conjunction with level gauge 7, can precisely control the liquid level in the evaporator, ensuring that the refrigerant level is always at the target height.
[0033] The electric heat pump evaporator 10 has its heat source inlet 5 connected to a low-temperature heat source. The refrigerant inside the shell 4 of the electric heat pump evaporator 10 is Freon, which effectively absorbs heat from the low-temperature heat source. The refrigerant vapor outlet 3 of the electric heat pump evaporator 10 is connected in sequence via pipes to the compressor COM, the heat source inlet 5 of the absorption heat pump evaporator 11, the heat source outlet 6 of the absorption heat pump evaporator 11, and the liquid refrigerant inlet 9 of the electric heat pump evaporator 10. The refrigerant inside the shell 4 of the absorption heat pump evaporator 11 is water. The refrigerant vapor outlet 3 of the absorption heat pump evaporator 11 is connected in sequence through pipes to the absorption heat pump absorber A, solution pump 12, solution heat exchanger EX, absorption heat pump generator G, absorption heat pump condenser C, and the liquid refrigerant inlet 9 of the absorption heat pump evaporator 11. The absorption heat pump generator G is connected in sequence through pipes to the solution heat exchanger EX and the absorption heat pump absorber A. The medium to be heated is discharged after being heated by the absorption heat pump absorber A and the absorption heat pump condenser C through pipes. The inlet of the absorption heat pump generator G is connected to the driving heat source.
[0034] By adopting the above connection method and refrigerant type, the intermediate circulating water in the conventional scheme is omitted, heat loss is reduced, and heat from low-temperature heat sources at lower temperatures (such as below 0°C) can be effectively extracted for heating or other process heat applications.
[0035] Work process:
[0036] A method for recovering low-temperature heat sources using an electrically operated compression-absorption heat pump unit with a coupled plate evaporator includes the following steps:
[0037] The low-temperature heat source is input into the heat exchange plate pair 1 through the heat source inlet 5 of the electric heat pump evaporator 10. After releasing heat, it is discharged from the heat source outlet 6 of the electric heat pump evaporator 10. The refrigerant Freon on the outside of the heat exchange plate pair 1 absorbs heat simultaneously. The refrigerant droplets splashed in the boiling evaporation state rise to the plate position that is not submerged by refrigerant. They exchange heat in the upper half of the plate. The evaporated refrigerant vapor is adsorbed by the liquid-blocking device 2 and then discharged through the refrigerant vapor outlet 3 of the electric heat pump evaporator 10. It enters the compressor COM for compression to obtain refrigerant vapor after temperature and pressure increase.
[0038] After being heated and pressurized, the refrigerant vapor is fed into the heat exchange plate pair 1 of the absorption heat pump evaporator 11 through the heat source inlet 5. After releasing heat in the plate pair 1, the vapor is cooled into liquid refrigerant and then enters the liquid refrigerant inlet 9 of the electric heat pump evaporator 10 through the heat source outlet 6 and valve 8 of the absorption heat pump evaporator 11. The above process is repeated.
[0039] In the absorption heat pump evaporator 11, the coolant water absorbs the heat released by the condensation process of the medium inside the heat exchange plate. The coolant water boils and evaporates, and a film heat exchange occurs in the upper half of the plate. The evaporated refrigerant vapor is discharged through the liquid-blocking device 2 and the refrigerant vapor outlet 3 of the absorption heat pump evaporator 11, and enters the absorption heat pump absorber A. The lithium bromide solution in the absorption heat pump absorber A absorbs the coolant water and releases heat during the dilution process. After dilution, the lithium bromide solution is concentrated in the absorption heat pump generator G by the solution pump 12. The concentrated lithium bromide solution returns to the absorption heat pump absorber A via the solution heat pump. The inlet of the absorption heat pump generator G is connected to a driving heat source to achieve the concentration of the lithium bromide solution. During the concentration process in the absorption heat pump generator G, the lithium bromide solution generates water vapor. The water vapor enters the absorption heat pump condenser C, where it releases heat and cools down before entering the interior of the absorption heat pump evaporator 11 through the valve 8 and the liquid refrigerant inlet 9.
[0040] The medium to be heated passes through a pipeline sequentially through the absorption heat pump absorber A and the absorption heat pump condenser C to absorb heat and increase its temperature. The medium to be heated can be hot water from the heating process.
[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.
Claims
1. An electrically operated compression-absorption heat pump unit with a coupled plate evaporator, characterized in that, The system includes an electric heat pump evaporator, a compressor, an absorption heat pump absorber, an absorption heat pump evaporator, an absorption heat pump generator, an absorption heat pump condenser, and a solution heat exchanger. The electric heat pump evaporator and the absorption heat pump evaporator have the same structure, both being plate-type rising film evaporators. The evaporator includes a shell, inside which are provided a pair of heat exchange plates. The pair of heat exchange plates has a heat source inlet and a heat source outlet. Refrigerant is disposed between the shell and the pair of heat exchange plates. The top of the shell has a refrigerant vapor outlet, and the bottom of the shell has a liquid refrigerant inlet. The electric heat pump evaporator's heat source inlet is connected to a low-temperature heat source. The electric heat pump evaporator's refrigerant vapor outlet is connected in sequence via pipes to the compressor, the absorption heat pump evaporator's heat source inlet, the absorption heat pump evaporator's heat source outlet, and the electric heat pump evaporator's liquid refrigerant inlet. The absorption heat pump evaporator's refrigerant vapor outlet is connected in sequence via pipes to the absorption heat pump absorber, the solution heat exchanger, the absorption heat pump generator, the absorption heat pump condenser, and the absorption heat pump evaporator's liquid refrigerant inlet. The absorption heat pump generator is connected in sequence via pipes to the solution heat exchanger and the absorption heat pump absorber. The medium to be heated is discharged after being heated by the absorption heat pump absorber and the absorption heat pump condenser through pipes. The absorption heat pump generator's inlet is connected to a driving heat source.
2. The electrically operated compression-absorption heat pump unit with a coupled plate evaporator according to claim 1, characterized in that, Multiple sets of heat exchange plates are arranged in parallel inside the shell. Each set of heat exchange plates has two opposite interfaces on its upper side, which are respectively connected to the heat source inlet and the heat source outlet.
3. The electrically operated compression-absorption heat pump unit with a coupled plate evaporator according to claim 2, characterized in that, Each heat exchange plate pair consists of two plates with internal media channels. The two plates are connected around their perimeter by laser, resistance sealing welding, or brazing.
4. The electrically operated compression-absorption heat pump unit with a coupled plate evaporator according to claim 1, characterized in that, The housing is equipped with a liquid-blocking device located at the top of the housing. The liquid-blocking device consists of several vertically arranged baffles, and the refrigerant vapor outlet is located above the liquid-blocking device.
5. The electrically operated compression-absorption heat pump unit with a coupled plate evaporator according to claim 1, characterized in that, The housing is equipped with a level gauge, and the refrigerant level in the evaporator is lower than the height of the heat exchange plate.
6. The electrically operated compression-absorption heat pump unit with a coupled plate evaporator according to claim 5, characterized in that, The level gauge is one of the following: differential pressure level gauge, float level gauge, magnetic level gauge, tuning fork level gauge, or guided wave radar level gauge.
7. The electrically operated compression-absorption heat pump unit with a coupled plate evaporator according to claim 1, characterized in that, A valve is installed on the inlet connection pipe of the liquid refrigerant.
8. The electrically operated compression-absorption heat pump unit with a coupled plate evaporator according to claim 7, characterized in that, The valve is one of the following: electric valve, solenoid valve, float valve, or thermostatic expansion valve.
9. The electrically operated compression-absorption heat pump unit with a coupled plate evaporator according to claim 1, characterized in that, The refrigerant inside the evaporator housing of the electric heat pump is Freon.
10. The electrically operated compression-absorption heat pump unit with a coupled plate evaporator according to claim 1, characterized in that, The refrigerant inside the evaporator shell of the absorption heat pump is water.