Heat exchanger refrigerant pipeline staggered single-stage heat pump module and cascade heat pump system

Abstract

The utility model relates to a heat exchanger refrigerant pipeline staggered single-stage heat pump module and a cascade heat pump system, the single-stage heat pump module is composed of at least two sets of heat pump subsystems, the single-stage heat pump module comprises at least two compressors, a condenser module, at least two throttling devices and an evaporator module, each of the evaporator module and the condenser module comprises a fin array and at least two sets of refrigerant pipelines penetrating through the fin array, and the at least two sets of refrigerant pipelines are distributed in a staggered manner; and one compressor, one set of refrigerant pipeline of the condenser module, one throttling device and one set of refrigerant pipeline of the evaporator module are sequentially connected to form a set of refrigerant circulation loop of the heat pump subsystem.

Description

Technical Field

[0001] The utility model relates to the technical field of heat pump design, in particular to a single-stage heat pump module with staggered refrigerant pipes of a heat exchanger and a cascade heat pump system. Background Art

[0002] When heat pump units are used in scenarios such as grain drying, the drying air flow is usually heated from an ambient temperature of around 20°C to around 70°C required for the drying process, with a large temperature increase. If a high-power single-system heat pump unit's condenser is used for one-time heating, the heat pump unit's cycle temperature rise (condensing temperature - evaporating temperature) will be very high, and the heating efficiency ratio (COP) (COP = condenser heating power / system electrical power), a core technical indicator of the heat pump unit that is inversely related to the cycle temperature rise, will become very low, even below 1.5. The economic efficiency of the heat pump unit will therefore become very poor, losing its commercial value and market significance.

[0003] In order to improve the heating efficiency of heat pump units in scenarios such as grain drying, heat pump companies usually use a method of cascading multiple sets of small-power single-unit heat pump subsystem condensers and implementing cascaded low-power heating of the dry airflow to improve the comprehensive heating efficiency ratio (COP).

[0004] For example, the heat pump evaporator absorbs heat from the 20℃ ambient air and then heats the dry air flow through the condenser to make it heat up from 20℃ to 70℃, which is a large-span 50℃ total temperature rise. This can be decomposed into multiple sets of small-power single-unit heat pump subsystems. The evaporator absorbs heat from the ambient air and then heats the dry air flow through multiple condensers to heat the dry air flow in multiple small stages and small-power cascade temperature rises. For example, it can be decomposed into a gradual temperature rise of the dry air flow from the ambient temperature of 20℃ to 36.7℃, 36.7℃ to 53.4℃, and 53.4℃ to 70℃. The above three steps are completed in stages. The "ultra-high COP" and "high COP" of the dry airflow in the early and middle low-power cascade temperature rise stages of 20℃→36.7℃ (COP≥6) and 36.7℃→53.4℃ (COP≥4) in this three-stage temperature rise combination are used to offset and neutralize the "ultra-low COP" of the dry airflow from 20℃→70℃ with a one-time high-power 50℃ total temperature rise of less than 1.5, thereby obtaining a higher comprehensive heating energy efficiency ratio (≥2.5) of the whole system of the heat pump unit.

[0005] Obviously, in a heat pump system where multiple sets of small-power stand-alone heat pump subsystem condensers are arranged in tiered configurations and the dry air flow is heated in tiered low-power steps to improve the overall COP, the more sets of heat pump subsystems there are, the more small steps there are, the smaller the temperature rise of each step, and the higher the overall heating energy efficiency ratio of the entire large heat pump system.

[0006] However, this cascade heat pump system consisting of multiple low-power stand-alone heat pump subsystems has two problems:

[0007] 1. Poor adaptability to variable loads

[0008] When the heat load demand of the drying device decreases due to factors such as a decrease in the amount of material fed into the drying device or an increase in the ambient temperature, the above-mentioned cascade heat pump system can only reduce the thermal power output by stopping the operation of some of the low-power single-unit heat pump subsystems, thereby reducing the number of "stages". For example, a three-stage cascade heat pump system can be reduced to a two-stage cascade heat pump system or even a single-stage heat pump system, and the corresponding comprehensive COP is also reduced.

[0009] 2. Difficulty in cleaning the evaporator

[0010] When the evaporator of the cascade heat pump system recovers heat from the return air of the drying device, a condensed water film forms on the evaporator fins, which cools, dehumidifies and removes moisture from the return air. Condensation occurs wherever there is heat absorption and cooling. The condensed water film is evenly distributed on both sides of the fins and continues to grow evenly. The double-layered condensed water film on the fins absorbs dust from the subsequent return air, mixing it into mud. Some of it slides down into the water tray, and some adheres to the evaporator fins.

[0011] When the heat load demand of the drying device decreases due to reasons such as a decrease in drying load or an increase in ambient temperature, the evaporator fins of the heat pump subsystems that have stopped running in the cascade heat pump system cannot maintain the condensed water film on both sides of the fins due to the cessation of cooling and dehumidification capabilities, causing the dust slurry attached to these fins to dry and solidify. These dust slurries containing a large amount of biomass components ferment and mildew, causing the air duct to be blocked, resulting in corrosion of the evaporator fins and making them difficult to clean. Utility Model Content

[0012] In order to solve the above problems, the utility model provides a single-stage heat pump module with staggered refrigerant pipelines of a heat exchanger, which is composed of at least two sets of heat pump subsystems. The single-stage heat pump module includes at least two compressors, a condenser module, at least two throttling devices and an evaporator module. The evaporator module and the condenser module both include a fin array and at least two sets of refrigerant pipelines passing through the fin array. These at least two sets of refrigerant pipelines are staggered; one of the compressors, a set of refrigerant pipelines of the condenser module, one of the throttling devices and a set of refrigerant pipelines of the evaporator module are connected in sequence to form a refrigerant circulation loop of a heat pump subsystem.

[0013] Preferably, each set of refrigerant piping includes a plurality of refrigerant branches passing through the fin array, and the plurality of refrigerant branches are arranged in parallel;

[0014] The refrigerant branches of these sets of refrigerant pipelines are arranged alternately to form a staggered structure.

[0015] Preferably, the fin array is composed of a plurality of fins arranged in parallel;

[0016] Each refrigerant branch is a serpentine tube, which includes a plurality of straight tube sections respectively passing through a plurality of the fins, and the plurality of straight tube sections are connected in series through the bent tube sections at their ends to form a serpentine tube;

[0017] The straight pipe sections of the refrigerant branches in two adjacent rows are staggered.

[0018] A cascade heat pump system comprises at least two sets of the above-mentioned single-stage heat pump modules.

[0019] Preferably, the device is used to recover the heat of the air outlet of the drying device in a stepwise manner and to heat the dry air flow in a stepwise manner, wherein the drying device comprises a dry air flow inflow channel, a drying section, and a dry air flow outflow channel, wherein both the dry air flow inflow channel and the dry air flow outflow channel are connected to the drying section;

[0020] All condenser modules are arranged in the dry air flow inflow channel, and are arranged sequentially and at intervals from the inlet side of the dry air flow inflow channel to the drying section; each evaporator module corresponding to each condenser module is arranged in the dry air flow outflow channel, and are arranged sequentially and at intervals from the outlet side of the dry air flow outflow channel to the drying section.

[0021] Preferably, it comprises a plurality of first single-stage heat pump modules and a plurality of second single-stage heat pump modules, wherein the compressor motor power of the first single-stage heat pump modules is greater than the compressor motor power of the second single-stage heat pump modules.

[0022] Preferably, the compressor motor power of the first single-stage heat pump module is twice the compressor motor power of the second single-stage heat pump module.

[0023] Preferably, it further comprises at least one single-stage heat pump unit consisting of a set of heat pump sub-units, wherein the condenser of the single-stage heat pump unit is located in the dry air flow inlet channel, and the evaporator of the single-stage heat pump unit is located in the dry air flow outflow channel.

[0024] Preferably, the motor power of the compressor of the single-stage heat pump unit is twice the motor power of the compressor of the single-stage heat pump module.

[0025] Compared with the prior art, the present invention has the following technical effects:

[0026] 1. It is beneficial for the heat recovery evaporator of the drying device to adsorb and clean the return air dust

[0027] When the utility model cools down, dehumidifies and removes moisture from the return air of the drying device, i.e., implements heat recovery, the evaporator is arranged in the return air duct, and a condensed water film is formed on both sides of all the fins of the evaporator; the double-layer condensed water film absorbs the dust in the subsequent return air, mixing it into mud, part of which slides down and falls into the water receiving tank, and part adheres to the evaporator fins;

[0028] Since the refrigerant pipelines of the evaporator modules of two or more heat pump subsystems of each single-stage heat pump module of the utility model are staggered, even if the evaporator fins of the heat pump subsystem stop running due to the reduction of drying load, they still have partial cooling and dehumidification capabilities due to the thermal bridge effect of the fins, and maintain the condensed water film on both sides of the fins, so that the dust attached to this part of the fins is dissolved into mud without drying or solidifying, which makes it difficult to clean it later; when the spray cleaning is started, the water mist particles sprayed by the high-pressure nozzle pass through the gap between the evaporator fins under the influence of gravity and the return air flow, and it is easy to flush and clean the mud attached to the surface of these fins; the utility model implements drying dust evaporator adsorption cleaning, which not only recovers the high enthalpy heat of the return air of the drying device, but also eliminates the complex dust removal facilities such as the ash room, cyclone dust collector, and filter cartridge dust collector of the drying device, fundamentally solving the problem of pollution of the heat recovery heat pump system evaporator by the return air dust of the heat pump drying device.

[0029] 2. When the load is reduced, the number of stages in the cascade heat pump system remains unchanged to prevent the COP from decreasing.

[0030] When the heat load demand of the drying device heated by the cascade heat pump system decreases due to a decrease in the amount of material fed, a decrease in the temperature rise of the drying airflow caused by an increase in ambient temperature, the utility model reduces the thermal power output by stopping the operation of some or all of the heat pump subsystems in the single-stage heat pump modules, thereby maintaining the number of stages in the cascade heat pump system unchanged and stabilizing the corresponding comprehensive COP without decreasing.

[0031] 3. When the load is reduced, the COP of the heat pump subsystem in each single-stage heat pump module continues to operate

[0032] When the heat load demand of the cascade heat pump system decreases due to the reduction of the feed amount of the drying device and the reduction of the temperature rise of the drying air flow as the ambient temperature rises, the heat power output is reduced by stopping the operation of some or all heat pump subsystems in the single-stage heat pump modules. The heat pump subsystems that continue to operate obtain the heat exchange area of the heat exchanger fins of the stopped heat pump subsystem due to the misalignment of the refrigerant pipes of the heat exchanger, resulting in a reduction in the heat transfer temperature difference between the inside and outside of the heat exchanger, thereby reducing the difference between the condensing temperature and the evaporating temperature of the subsystems, bringing about a further improvement in the heating energy efficiency ratio (COP).

[0033] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive efforts. In the drawings:

[0035] Figure 1 A schematic structural diagram of a single-stage heat pump module with staggered refrigerant pipes in the heat exchanger provided in the preferred embodiment 1 of the present invention;

[0036] Figure 2 A schematic structural diagram of a cascade heat pump system according to a preferred embodiment 2 of the present invention;

[0037] Figure 3 A schematic structural diagram of a cascade heat pump system according to a preferred embodiment 3 of the present invention;

[0038] Figure 4 This is a structural diagram of a cascade heat pump system provided in preferred embodiment 4 of the present invention. DETAILED DESCRIPTION

[0039] The following will be combined Figures 1 to 4 The single-stage heat pump module with staggered refrigerant pipes in the heat exchanger and the cascade heat pump system provided by the present invention are described in detail. This embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation method and specific operation process are given. However, the protection scope of the present invention is not limited to the following embodiments. Those skilled in the art can modify and polish it without changing the spirit and content of the present invention.

[0040] Example 1

[0041] Please refer to Figure 1This embodiment provides a single-stage heat pump module 1 with staggered heat exchanger refrigerant pipelines. A single-stage heat pump module 1 includes at least two heat pump subsystems. These heat pump subsystems use an integrated evaporator module and an integrated condenser module, that is, these heat pump subsystems use the same evaporator module and the same condenser module. Each single-stage heat pump module 1 includes at least two compressors 11, a condenser module 14, at least two throttling devices 13, and an evaporator module 12. The evaporator module 12 and the condenser module 14 each include a fin array and at least two sets of refrigerant pipelines passing through the fin array. These at least two sets of refrigerant pipelines are staggered, that is, these sets of refrigerant pipelines are not in the same row, and one set of refrigerant pipelines is embedded in another set or several other sets of refrigerant pipelines in an interlaced manner. A compressor 11, a set of refrigerant pipelines of the condenser module 14, a throttling device 13, and a set of refrigerant pipelines of the evaporator module 12 are sequentially connected to form a refrigerant circulation circuit of a heat pump subsystem. In this embodiment, the number of compressors 11 = the number of sets of refrigerant pipelines of the evaporator module 12 = the number of throttling devices 13 = the number of sets of refrigerant pipelines of the condenser module 14 .

[0042] In this embodiment, each set of refrigerant piping includes a plurality of refrigerant branches passing through the fin array, and these refrigerant branches are arranged in parallel;

[0043] The refrigerant branches of these sets of refrigerant pipelines are arranged alternately to form a staggered structure.

[0044] Specifically, the fin array is composed of a number of fins arranged in parallel;

[0045] Each refrigerant branch is a serpentine tube. Specifically, each refrigerant branch includes a plurality of straight tube sections respectively passing through a plurality of fins, and the plurality of straight tube sections are connected in series through curved tube sections at their ends to form a serpentine tube.

[0046] The straight pipe sections of the refrigerant pipe branches in two adjacent rows are staggered.

[0047] This embodiment does not limit the specific refrigerant circulating in the refrigerant pipeline, and it can be set according to actual usage requirements.

[0048] In this embodiment, the finned tube evaporator modules 12 and the finned tube condenser modules 14 of two or more heat pump subsystems of a single-stage heat pump module 1 are staggered using a refrigerant pipeline staggering technique. The finned thermal bridge effect on the refrigerant pipeline achieves integrated heat absorption of the evaporators and integrated heat release of the condensers of the two or more heat pump subsystems of the single-stage heat pump module 1.

[0049] Example 2

[0050] Please refer to Figure 2This embodiment adopts a cascade heat pump system, which includes at least two sets of single-stage heat pump modules 1 described in the above embodiment 1.

[0051] The cascade heat pump system provided in this embodiment is used to recover the heat of the air outlet of the drying device 2 in a cascade manner and to heat the dry air in a cascade manner. The drying device 2 includes a dry air flow inlet channel 21, a drying section 22, and a dry air flow outlet channel 23. The dry air flow inlet channel 21 and the dry air flow outlet channel 23 are both connected to the drying section 22.

[0052] All condenser modules 14 are arranged in the dry air flow inflow channel 21, and are arranged sequentially and at intervals from the inlet side of the dry air flow inflow channel 21 to the drying section 22; each evaporator module 12 corresponding to each condenser module 14 is arranged in the dry air flow outflow channel 23, and is arranged sequentially and at intervals from the outlet side of the dry air flow outflow channel 23 to the drying section 22, that is, the evaporator module 12 and condenser module 14 of the same set of the single-stage heat pump module 1 are respectively arranged in the same order from the drying section 22 in the dry air flow outflow channel 23 and the dry air flow inflow channel 21.

[0053] The cascade heat pump system provided in this embodiment uses a combination of two or more sets of low-power single-stage heat pump modules 1 (i.e., the single-stage heat pump modules 1 composed of at least two sets of heat pump subsystems described in the above embodiment 1) to replace the high-power single-stage heat pump unit; each single-stage heat pump unit is composed of two sets of heat pump subsystems, each heat pump subsystem including a compressor, a condenser, a throttling device, and an evaporator, and the compressor, condenser, throttling device, and evaporator are connected in sequence to form a refrigerant circulation loop; the evaporator modules 12 and condenser modules 14 of the multiple sets of single-stage heat pump modules 1 with staggered refrigerant pipelines are arranged in cascade in the corresponding dry air flow channels, the heat of the air outlet of the drying device 2 is cascaded by the multi-stage evaporator modules 12, and the dry air flow is cascaded by the multi-stage condenser modules 14, thereby reducing the difference between the condensing temperature and the evaporating temperature of each heat pump subsystem of each single-stage heat pump module 1, improving the COP of each heat pump subsystem of each single-stage heat pump module 1, and thus significantly improving the comprehensive heating energy efficiency ratio (COP) of the entire system.

[0054] When the heat load demand of the drying device 2 decreases, causing some subsystems of two or more heat pump subsystems in some single-stage heat pump modules 1 to stop operating, the heat pump subsystems that continue to operate utilize the heat exchanger fin resources of the stopped subsystem through the fin thermal bridge effect, expand the heat release area of the evaporator module 12 and the heat absorption condenser module 14, reduce the heat transfer temperature difference between the inside and outside of the evaporator module 12 and the condenser module 14, and improve the heating energy efficiency ratio; because of the fin thermal bridge effect, the fins of the evaporator module 12 and the condenser module 14 of the stopped heat pump subsystem in the single-stage heat pump module 1 are utilized by the running heat pump subsystem, partially maintaining the heat absorption and release capacity, and the fins of the evaporator module 12 continue to condense to prevent the dust and mud attached to this part of the fins from drying and solidifying, thereby ensuring the convenience of cleaning the fins of the evaporator module 12.

[0055] This embodiment does not impose any specific restrictions on the drying airflow, which can be air, nitrogen, carbon dioxide, etc. This embodiment does not impose any specific restrictions on the drying device, and can be applied to scenarios such as grain drying. The above content can be set according to specific usage requirements.

[0056] This embodiment does not limit the number of sets of single-stage heat pump modules 1 that the cascade heat pump system is composed of, and the number can be set according to actual use requirements. Figure 2 The figure shows that it is composed of three sets of single-stage heat pump modules 1. The evaporator modules 12 and condenser modules 14 of these three sets of single-stage heat pump modules 1, with staggered refrigerant pipelines, are arranged in stages in the corresponding dry air flow channels. The three-stage evaporator modules 12 are used to recover the heat of the air outlet of the drying device 2, and the three-stage condenser modules 14 are used to heat the dry air flow in stages. The condenser modules 14 of these three heat pump subsystems are arranged sequentially in the fresh air channel, and the evaporator modules 12 of these three heat pump subsystems are arranged in reverse order in the return air channel of the drying device 2. The evaporator modules 12 and condenser modules 14 of the same heat pump subsystem are arranged in the same order from the drying section 22 in the return air channel 23 and the fresh air channel 21, respectively. In this embodiment, the motor power of the compressor in each set of single-stage heat pump modules 1 is the same, and the motor power of the compressors in these sets of single-stage heat pump modules 1 is also the same.

[0057] Example 3

[0058] This embodiment is a further improvement on the basis of embodiment 2. The power of the multiple sets of single-stage heat pump modules 1 of the cascade heat pump system provided in embodiment 2 is the same, while the power of the multiple sets of single-stage heat pump modules of the cascade heat pump system provided in this embodiment varies. The specific structure is as follows:

[0059] Please refer to Figure 3This embodiment provides a cascade heat pump system, which is composed of two or more sets of low-power single-stage heat pump modules 1. These sets of single-stage heat pump modules 1 are further divided into a number of first single-stage heat pump modules 1' and a number of second single-stage heat pump modules 1", and the evaporator modules 12' and condenser modules 14' of the first single-stage heat pump modules 1' and the evaporator modules 12" and condenser modules 14" of the second single-stage heat pump modules 1" are arranged in cascade in the corresponding drying air flow channels, and the heat of the air outlet of the drying device 2 is recovered by multi-stage evaporators in cascade, and the drying air flow is heated by multi-stage condensers in cascade. The first single-stage heat pump module 1' and the plurality of second single-stage heat pump modules 1" have the same structure, but different motor powers. In this embodiment, the compressor motor power of the first single-stage heat pump module 1' is greater than the compressor motor power of the second single-stage heat pump module 1". As to whether the evaporator module 12' and the condenser module 14' of the first single-stage heat pump module 1' are close to the drying section 22 or the evaporator module 12" and the condenser module 14" of the second single-stage heat pump module 1" are close to the drying device 2, this embodiment does not impose any specific restrictions on this.

[0060] This embodiment does not limit where the second single-stage heat pump module 1" is arranged relative to the first single-stage heat pump module 1'. Figure 3 This cascade heat pump system includes three sets of first single-stage heat pump modules 1' and one set of second single-stage heat pump module 1", and there is no specific restriction on whether the second single-stage heat pump module 1" is arranged at the bottom, middle or top of the three sets of first single-stage heat pump modules 1'. Figure 3 It is shown that the second single-stage heat pump module 1" is arranged at the bottom of the first single-stage heat pump module 1', that is, the condenser module 14 of the second single-stage heat pump module 1" is arranged at the inlet of the dry air flow inlet channel 21, and the evaporator module 12 of the second single-stage heat pump module 1" is arranged at the outlet of the dry air flow outflow channel 23.

[0061] In this embodiment, the compressor motor power of the first single-stage heat pump module 1 ′ is twice the compressor motor power of the second single-stage heat pump module 1 ″.

[0062] This embodiment does not impose any specific restriction on the number of the first single-stage heat pump modules 1' and the second single-stage heat pump modules 1", and takes a cascade heat pump system including three sets of first single-stage heat pump modules 1' and one set of second single-stage heat pump modules 1" as an example for detailed description.

[0063] In this embodiment, the heat pump system includes three sets of first single-stage heat pump modules 1' and one set of second single-stage heat pump module 1", the first single-stage heat pump module 1' adopts an evaporator module 12' and a condenser module 14' matched with a compressor with a motor power of P; the second single-stage heat pump module 1" adopts an evaporator module 12" and a condenser module 14" matched with a compressor with a motor power of 0.5P. From the energy perspective of heat absorption and heat release, the heat absorption and release power of the second single-stage heat pump module 1" with two sets of 0.5P compressors is equivalent to 0.5 of the first single-stage heat pump module 1' with a compressor with a motor power of P, so the whole heat pump system is collectively referred to as a 3.5-stage configuration. Figure 3 shown.

[0064] Since this embodiment adopts two sets of heat pump subsystems to form a single-stage heat pump module 1 by staggering the refrigerant pipes of the evaporator module and the condenser module, in the above-mentioned scenario where the total power of the compressor motor reaches 3.5P or more and the corresponding 8 condenser heat power outputs, one set of heat pump subsystems in the single-stage heat pump module stops running due to the reduction of heat load demand, and the other set of heat pump subsystems that continues to run obtains the heat exchange area of the heat exchanger fins of the stopped heat pump subsystem due to the staggered arrangement of the heat exchanger refrigerant pipes, resulting in the effects of expanding the heat exchange area of the evaporator and condenser, reducing the temperature difference between the internal and external heat transfer, reducing the difference between the condensing temperature and the evaporating temperature, and further improving the heating energy efficiency ratio (COP).

[0065] This embodiment has all the advantages of Example 2, and because it uses a second single-stage heat pump module 1″ with a 0.5P compressor and a first single-stage heat pump module 1′ with a 1P compressor, by combining the on / off operations of the heat pump subsystems driven by two sets of 0.5P compressors and six sets of P compressors, with the heat pump subsystem driven by the 0.5P compressor as the basic energy unit, a condenser module thermal power output corresponding to the total power of 14 compressor motors, namely 0.5P, P, 1.5P, 2P, 2.5P, 3P, 3.5P, 4P, 4.5P, 5P, 5.5P, 6P, 6.5P, and 7P, can be combined. This embodiment has a smaller energy unit than a cascade heat pump of multiple groups of single-stage heat pump units consisting of a single-stage heat pump unit composed of one set of heat pump subsystems, has more thermal output power options, and has a broader energy spectrum.

[0066] Example 4

[0067] This embodiment is a further improvement on the basis of embodiment 2. The cascade heat pump system provided in embodiment 2 is composed of multiple sets of single-stage heat pump modules 1, and each set of single-stage heat pump modules 1 is composed of two sets of heat pump subsystems. The fin-tube heat exchangers (evaporator module 12 and condenser module 14) of these two sets of heat pump subsystems adopt the refrigerant pipeline staggered technology. The refrigerant pipelines are arranged at intervals from each other. The heat absorption and release of the heat exchangers of the two sets of heat pump subsystems of the single-stage heat pump module 1 are integrated through the fin thermal bridge effect on the refrigerant pipelines. Please refer to Figure 4 The cascade heat pump system provided in this embodiment includes not only the single-stage heat pump module 1 composed of the two sets of heat pump subsystems mentioned above, but also a single-stage heat pump unit 3 composed of one set of heat pump subsystems. The evaporator modules 12 and condenser modules 14 of the single-stage heat pump modules 1 and the evaporators 31 and condensers 32 of the single-stage heat pump units 3 are arranged in cascade in the corresponding drying air flow channels, and the heat of the air outlet of the drying device 2 is recovered in cascade by multi-stage evaporators, and the drying air flow is heated in cascade by multi-stage condensers.

[0068] In this embodiment, whether the evaporator module 12 and the condenser module 14 of the single-stage heat pump module 1 are close to the drying section 22 or the evaporator 31 and the condenser 32 of the single-stage heat pump unit 3 are close to the drying section 22 is not specifically limited in this embodiment. Preferably, the condenser module 14 of the single-stage heat pump module 1 is farther away from the inlet of the dry air flow inflow channel 21 than the condenser 32 of the single-stage heat pump unit 3, and is close to the drying section 22; the evaporator module 12 of the single-stage heat pump module 1 is farther away from the outlet of the dry air flow outflow channel 23 than the evaporator 31 of the single-stage heat pump unit 3, and is close to the drying section 22; that is, the condenser 32 of the single-stage heat pump unit 3 is close to the inlet of the dry air flow inflow channel 21, and the evaporator 31 of the single-stage heat pump unit 3 is close to the outlet of the dry air flow outflow channel 23.

[0069] In this embodiment, the compressor motor power of the single-stage heat pump module 1 is less than the compressor motor power of the single-stage heat pump unit 3. Preferably, the motor power of the compressor of the single-stage heat pump unit 3 is twice the motor power of the compressor of the single-stage heat pump module 1.

[0070] This embodiment does not limit the number of single-stage heat pump modules 1 and multiple single-stage heat pump units 3. Figure 4The three sets of single-stage heat pump modules 1 and the one set of single-stage heat pump units 3 are described. Each set of single-stage heat pump modules 1 includes two 1P compressors, and the single-stage heat pump unit 3 includes one 2P compressor. That is, this embodiment is a four-stage cascade heat pump system driven by six 1P compressors and one 2P compressor, a total of seven compressors, which has all the advantages of Example 2. This embodiment has eight levels of heat output power, corresponding to the total power of the compressor motor 1P, 2P, 3P, 4P, 5P, 6P, 7P, and 8P respectively. When all four stages are put into use, the number of operating compressors reaches four or more, and the total power of the compressor motor is 5P, 6P, 7P, and 8P respectively, the COP is the highest and the economy is the best.

Claims

1. A single-stage heat pump module with staggered refrigerant pipes in the heat exchanger, characterized in that: It is composed of at least two heat pump subsystems, the single-stage heat pump module includes at least two compressors, a condenser module, at least two throttling devices and an evaporator module, the evaporator module and the condenser module both include a fin array and at least two sets of refrigerant pipes passing through the fin array, and the at least two sets of refrigerant pipes are staggered; wherein, one of the compressors, a set of refrigerant pipes of the condenser module, one of the throttling devices and a set of refrigerant pipes of the evaporator module are sequentially connected to form a refrigerant circulation circuit of a heat pump subsystem.

2. The single-stage heat pump module with staggered refrigerant pipes in the heat exchanger according to claim 1, characterized in that: Each set of refrigerant piping includes a plurality of refrigerant branches passing through the fin array, and the plurality of refrigerant branches are arranged in parallel; The refrigerant branches of these sets of refrigerant pipelines are arranged alternately to form a staggered structure.

3. The single-stage heat pump module with staggered refrigerant pipes in the heat exchanger according to claim 2, characterized in that: The fin array is composed of a number of fins arranged in parallel; Each refrigerant branch is a serpentine tube, which includes a plurality of straight tube sections respectively passing through a plurality of the fins, and the plurality of straight tube sections are connected in series through the bent tube sections at their ends to form a serpentine tube; The straight pipe sections of the refrigerant branches in two adjacent rows are staggered.

4. A cascade heat pump system, characterized in that: The heat pump module comprises at least two sets of single-stage heat pump modules according to any one of claims 1 to 3.

5. The cascade heat pump system according to claim 4, characterized in that: Used to recover the heat of the air outlet of the drying device in a step-by-step manner and to heat the dry air flow in a step-by-step manner, the drying device comprising a dry air flow inflow channel, a drying section and a dry air flow outflow channel, the dry air flow inflow channel and the dry air flow outflow channel both being connected to the drying section; All condenser modules are arranged in the dry air flow inflow channel, and are arranged sequentially and at intervals from the inlet side of the dry air flow inflow channel to the drying section; each evaporator module corresponding to each condenser module is arranged in the dry air flow outflow channel, and are arranged sequentially and at intervals from the outlet side of the dry air flow outflow channel to the drying section.

6. The cascade heat pump system according to claim 5, characterized in that: The two or more sets of the single-stage heat pump modules are divided into several first single-stage heat pump modules and several second single-stage heat pump modules. The compressor motor power of the first single-stage heat pump module is greater than the compressor motor power of the second single-stage heat pump module.

7. The cascade heat pump system according to claim 6, characterized in that: The compressor motor power of the first single-stage heat pump module is twice the compressor motor power of the second single-stage heat pump module.

8. The cascade heat pump system according to claim 5, characterized in that: It also includes at least one single-stage heat pump unit consisting of a set of heat pump sub-units, the condenser of the single-stage heat pump unit is located in the dry air flow inlet channel, and the evaporator of the single-stage heat pump unit is located in the dry air flow outflow channel.

9. The cascade heat pump system according to claim 8, characterized in that: The motor power of the compressor of the single-stage heat pump unit is twice the motor power of the compressor of the single-stage heat pump module.

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