A dual-source heat pump cascade high-temperature heating system

Abstract

This invention discloses a dual-source heat pump cascade high-temperature heating system, relating to the technical field of high-temperature heat pump systems. The system includes heat pump units and intermediate heat exchangers. A hot-end heat exchanger is located on the heating side, and a cold-end heat exchanger is located on the cooling side. Multiple heat pump units are positioned between the hot-end and cold-end heat exchangers, and multiple intermediate heat exchangers are positioned between adjacent heat pump units. A heat-extracting medium is continuously introduced into the cold-end heat exchanger to facilitate heat transfer from adjacent heat pump units. A heat-absorbing medium is continuously introduced into the hot-end heat exchanger to absorb the heat transferred by the heat pump units. The heat absorbed by the cold-end heat exchanger is progressively transferred and amplified through multiple heat pump units and intermediate heat exchangers, and then released centrally at the hot-end heat exchanger. The heating side continuously outputs superheated high-temperature hot water or steam, while the cooling side continuously outputs subcooled low-temperature cold water or cold air. This system achieves high-quality heating in low-temperature environments, simultaneously meeting the needs of combined heating and cooling, and features a reliable structure, strong load adaptability, and high energy efficiency.

Description

Technical Field

[0001] This invention relates to the field of heat pump high-temperature system technology, and in particular to a dual-source heat pump cascade high-temperature heating system. Background Technology

[0002] An air source heat pump is a typical energy-saving heating device. Its basic principle is to use a compressor and heat exchanger to transfer heat from a low-grade heat source to a high-grade heat source, thereby heating water or air. However, the performance of an air source heat pump is highly dependent on the ambient temperature. When the outside temperature drops, the heat pump's ability to extract heat from the low-temperature air decreases significantly, and its heating performance drops markedly. Especially in cold northern regions during winter, its coefficient of performance (COP) is often low, making it difficult to meet stable heating demands.

[0003] Most existing heat pumps use a single compressor structure. When the ambient temperature is below 0°C, except for systems using carbon dioxide as the working fluid, conventional compressors are unable to output high-temperature hot water. Because the compression ratio of a single compressor is too high under low-temperature conditions, forced operation will cause equipment overload or even damage. In addition, heating conditions in northern regions are generally below 10°C, and existing single-compressor heat pumps cannot achieve a stable supply of high-temperature hot water, thus limiting their application in extremely cold regions. An even more prominent problem is that existing heat pumps are prone to frequent defrosting in low-temperature environments, resulting in the inability of hot water to continuously heat up and hindering heat output.

[0004] To overcome this limitation, some systems have introduced cascade heat pump units. These units operate by cascading two or more compressors, enabling them to achieve higher water temperature output at lower temperatures, thus compensating for the shortcomings of single-compressor heat pumps to some extent.

[0005] Cascade heat pumps can meet the demand for stable high-temperature hot water in some high-load applications; however, these units have complex structures, large equipment sizes, and sophisticated operating control logic, and are mostly designed for stable load conditions, thus having limitations when dealing with variable loads or combined cooling and heating scenarios. Especially at the hot water end, their output temperature is often constrained, making it difficult to quickly produce high-temperature hot water, let alone efficiently generate steam. This hinders the utilization of the heat pump's high thermal efficiency and energy-saving characteristics in scenarios with urgent needs for high-temperature heat sources, such as industrial hot water, medical disinfection, or district heating.

[0006] In summary, the existing technology has at least the following technical problems:

[0007] Existing cascade heat pumps suffer from technical problems such as complex structure, insufficient reliability, performance degradation at low temperatures, insufficient adaptability to load changes, and limited temperature rise at the hot water end, making them difficult to adapt to combined high-temperature heating and cooling / heating conditions. Summary of the Invention

[0008] The purpose of this invention is to provide a dual-source heat pump cascade high-temperature heating system to solve the technical problems of existing cascade heat pumps, such as complex structure, insufficient reliability, performance degradation under low-temperature conditions, insufficient adaptability to load changes, and limited hot water end temperature rise, which makes it difficult to adapt to the combined working conditions of high-temperature heating and combined cooling and heating.

[0009] The preferred technical solutions among the many technical solutions provided by this invention can produce a variety of technical effects, which are described in detail below.

[0010] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0011] This invention provides a dual-source heat pump cascade high-temperature heating system, comprising multiple heat pump units and multiple intermediate heat exchangers; a hot-end heat exchanger is provided on the heating side, and a cold-end heat exchanger is provided on the cooling side; the multiple heat pump units are all disposed between the hot-end heat exchanger and the cold-end heat exchanger, and the intermediate heat exchanger is disposed between two adjacent heat pump units; the cold-end heat exchanger continuously receives a heat-extracting medium to continuously transfer heat from adjacent heat pump units; the hot-end heat exchanger continuously receives a heat-absorbing medium to continuously absorb heat transferred from adjacent heat pump units. The heat absorbed by the cold-end heat exchanger is transported to the hot-end heat exchanger through multiple heat pump units and multiple intermediate heat exchangers. This allows the heat in the cold-end heat exchanger to be continuously absorbed and its quality to be increased multiple times. The heat is then released at an ultra-high quality in the hot-end heat exchanger, ensuring that the heat obtained by the heating side is sufficient and can be continuously and rapidly heated. The heating side continuously outputs superheated high-temperature hot water or high-temperature steam, allowing the heat from the cooling side to be continuously removed to obtain sufficient cooling capacity. The cooling side continuously outputs supercooled low-temperature cold water or low-temperature cold air.

[0012] In one embodiment, the heat pump unit includes at least one compressor and an electronic expansion valve; the heat pump unit is provided with three heat pumps, namely a first heat pump, a second heat pump and a third heat pump; the intermediate heat exchanger is provided with two heat exchangers, namely a first heat exchanger and a second heat exchanger.

[0013] In one embodiment, the inlet of the compressor of the first heat pump is connected to the outlet of the heat-releasing side of the hot-end heat exchanger, the outlet of the compressor is connected to the inlet of the heat-absorbing side of the first heat exchanger, and the outlet of the heat-absorbing side of the first heat exchanger is connected to the electronic expansion valve of the first heat pump, which is connected to the inlet of the heat-releasing side of the hot-end heat exchanger; the inlet of the compressor of the second heat pump is connected to the outlet of the heat-releasing side of the first heat exchanger, the outlet of the compressor is connected to the inlet of the heat-absorbing side of the second heat exchanger, and the outlet of the heat-absorbing side of the second heat exchanger is connected to the electronic expansion valve of the second heat pump, which is connected to the inlet of the heat-releasing side of the first heat exchanger; the inlet of the compressor of the third heat pump is connected to the outlet of the heat-releasing side of the second heat exchanger, the outlet of the compressor is connected to the inlet of the heat-absorbing side of the cold-end heat exchanger, and the outlet of the heat-absorbing side of the cold-end heat exchanger is connected to the electronic expansion valve of the third heat pump, which is connected to the inlet of the heat-releasing side of the second heat exchanger.

[0014] In one embodiment, low-pressure units are provided between the inlet of the compressor of the first heat pump and the outlet of the heat-releasing side of the hot-end heat exchanger, between the inlet of the compressor of the second heat pump and the outlet of the heat-releasing side of the first heat exchanger, and between the inlet of the compressor of the third heat pump and the outlet of the heat-releasing side of the second heat exchanger. The low-pressure unit includes a first pressure sensor and a first valve. The first pressure sensor monitors the pressure of the low-pressure circuit of the compressor of the current heat pump unit, and controls the opening of the first valve based on the heat exchange demand of the current heat pump unit, thereby realizing independent flow regulation of the low-pressure circuits of the first heat pump, the second heat pump, and the third heat pump.

[0015] In one embodiment, high-pressure units are provided between the outlet of the compressor of the first heat pump and the inlet of the heat absorption side of the first heat exchanger, between the outlet of the compressor of the second heat pump and the inlet of the heat absorption side of the second heat exchanger, and between the outlet of the compressor of the third heat pump and the inlet of the heat absorption side of the cold end heat exchanger. The high-pressure unit includes a second pressure sensor and a second valve. The pressure of the high-pressure circuit of the compressor of the current heat pump unit is monitored by the second pressure sensor, and the opening degree of the second valve is controlled by considering the heat exchange demand of the current heat pump unit, so as to realize independent flow regulation of the high-pressure circuits of the first heat pump, the second heat pump and the third heat pump.

[0016] In one embodiment, exhaust valves are provided between the compressor outlet of the first heat pump and the high-pressure unit, between the compressor outlet of the second heat pump and the high-pressure unit, and between the compressor outlet of the third heat pump and the high-pressure unit. The exhaust valves are used to release pressure and control the current pipeline pressure to return to the threshold range when the pressure in the high-pressure circuit of the compressor of the current heat pump unit is too high, and the pressure between the compressor outlet and the high-pressure unit is still too high even after controlling the opening of the first valve and the second valve.

[0017] In one embodiment, the compressor of the first heat pump is a variable frequency compressor, while the compressors of the second and third heat pumps are both fixed frequency compressors. By arranging the two fixed frequency compressors of the second and third heat pumps adjacent to the cooling side and arranging the variable frequency compressor of the first heat pump adjacent to the heating side, the cooling side can continuously supply cold water or cold air in summer and continuously supply heat in winter, while the cold water or cold air produced is directly discharged or the heat is transported, so that the heating side can continuously provide high-temperature hot water or high-temperature steam in both summer and winter.

[0018] In one embodiment, the cooling side is provided with a cooling capacity intake end and a geothermal heat exchange end, and water is introduced as the heat exchange medium; the cooling capacity intake end is located on the outlet side of the cold end heat exchanger for discharging cooling capacity; the geothermal heat exchange end is located on the inlet side of the cold end heat exchanger for transporting geothermal heat; the inlet side of the cold end heat exchanger is provided with a water source compensation port for replenishing the heat exchange water and providing additional heat; the cooling capacity intake end is provided with a cold water intake unit and a cold water discharge unit in sequence along the water outlet direction.

[0019] In one embodiment, the cold water intake unit is provided with a water pipe and cooling fins; the cold water discharge unit is provided with a drain port and heat absorption fins; the water outlet pipe of the water outlet port of the heat absorption fins is connected between the geothermal heat exchange end and the water inlet side of the cold end heat exchanger, for directly inputting the heat absorbed from the air into the cold end heat exchanger.

[0020] In one embodiment, both the hot-end heat exchanger and the cold-end heat exchanger are water-source heat exchangers.

[0021] In response to the problems of complex structure, insufficient reliability, low-temperature performance degradation, insufficient load adaptability and limited hot water end temperature of existing cascade heat pumps, this invention proposes a technical solution for a dual-source heat pump cascade high-temperature heating system, which has the following beneficial effects: (1) Realizes multi-level superposition and release of high-grade heat: Through the coordinated arrangement of multiple heat pump units and multiple intermediate heat exchangers, the low-grade heat absorbed by the cold end heat exchanger is transferred and superimposed multiple times, and finally released as ultra-high-grade heat in the hot end heat exchanger, so that the heating side can stably obtain superheated high-temperature hot water or high-temperature steam, breaking through the bottleneck of limited hot water end temperature of traditional cascade heat pumps.

[0022] (2) The dual-source characteristics of high-temperature heating and low-temperature cooling are taken into account: the system is set up with heating side and cooling side at the same time. Through the dual-loop structure of hot end heat exchanger and cold end heat exchanger, the coordinated operation of heating and cooling is realized. The heating side can continuously output high-temperature hot water or steam, while the cooling side can continuously output subcooled low-temperature cold water or cold air to meet the needs of combined heating and cooling operation.

[0023] (3) Improve the operating performance in low temperature environment: The cold end heat exchanger continuously introduces heat extraction medium, so that the heat pump unit can continue to extract and transfer heat in low temperature air or water environment, which reduces the performance degradation problem of traditional cascade heat pump system under low temperature conditions and improves the operating stability and energy efficiency level in cold regions.

[0024] (4) Enhance the load adaptability and reliability of the system: Through the modular structure of multi-stage heat pump units and intermediate heat exchangers, the system can flexibly and independently adjust the operating power of the heat pump units put into operation, and realize adaptive adjustment to different load conditions; at the same time, the multi-stage superimposed heat exchange method reduces the excessively high compression ratio of a single compressor, avoids the risk of compressor damage, and thus improves the overall reliability and service life.

[0025] In summary, the modular structure of the multi-stage heat pump unit and intermediate heat exchanger, with independent and flexible adjustment capabilities within the modules, makes the invention suitable not only for winter heating in cold northern regions, but also for industrial steam preparation, medical disinfection, food processing, and combined cooling and heating systems, thus possessing broader application value. Attached Figure Description

[0026] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the structure of the dual-source heat pump cascade high-temperature heating system of the present invention;

[0028] Figure 2 This is a schematic diagram of the dual-loop redundant valve group of the present invention;

[0029] Figure 3 This is a schematic diagram of the structure of the present invention for efficiently supplying heat source.

[0030] The accompanying figure is labeled as follows:

[0031] 1. Heat pump unit; 11. Compressor; 12. Electronic expansion valve; 13. Low-pressure unit; 14. High-pressure unit; 15. Exhaust valve;

[0032] 2. First heat pump;

[0033] 3. Second heat pump;

[0034] 4. Third heat pump;

[0035] 5. Intermediate heat exchanger;

[0036] 6. First heat exchanger;

[0037] 7. Second heat exchanger;

[0038] 8. Hot-end heat exchanger;

[0039] 9. Cold end heat exchanger; 91. Cold energy intake end; 911. Cold water intake unit; 912. Cold water discharge unit; 92. Water source compensation port; 93. Geothermal heat exchange end. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0041] A specific embodiment provides a dual-source heat pump cascade high-temperature heating system. This system includes heat pump units and intermediate heat exchangers. A hot-end heat exchanger is provided on the heating side, and a cold-end heat exchanger is provided on the cooling side. Multiple heat pump units are disposed between the hot-end and cold-end heat exchangers, and multiple intermediate heat exchangers are respectively disposed between adjacent heat pump units. A heat-extracting medium is continuously introduced into the cold-end heat exchanger to facilitate heat transfer from adjacent heat pump units. A heat-absorbing medium is continuously introduced into the hot-end heat exchanger to absorb the heat transferred by the heat pump units. The heat absorbed by the cold-end heat exchanger is then transferred through multiple heat pump units and multiple intermediate heat exchangers. The intermediate heat exchangers are transported and stacked in stages, and the heat is released centrally at the hot end heat exchanger. The heating side continuously outputs superheated high-temperature hot water or steam, while the cooling side continuously outputs subcooled low-temperature cold water or cold air. This achieves high-quality heating in low-temperature environments, while also meeting the needs of combined heating and cooling. It also has the advantages of reliable structure, strong load adaptability, and high energy efficiency. It effectively solves the technical problems of existing cascade heat pumps, such as complex structure, insufficient reliability, performance degradation in low-temperature environments, insufficient adaptability to load changes, and limited temperature rise at the hot water end, which make it difficult to adapt to the combined operation of high-temperature heating and combined heating and cooling.

[0042] The first implementation of a dual-source heat pump cascade high-temperature heating system, for example Figure 1 As shown, it includes multiple heat pump units 1 and multiple intermediate heat exchangers 5; a hot-end heat exchanger 8 is provided on the heating side, and a cold-end heat exchanger 9 is provided on the cooling side; multiple heat pump units 1 are all arranged between the hot-end heat exchanger 8 and the cold-end heat exchanger 9, and the intermediate heat exchangers 5 are arranged between two adjacent heat pump units 1; the cold-end heat exchanger 9 is continuously supplied with a heat-extracting medium to continuously transfer heat from the adjacent heat pump units 1; the hot-end heat exchanger 8 is continuously supplied with a heat-absorbing medium to continuously absorb the heat transferred by the adjacent heat pump units 1; by... The heat absorbed by the cold-end heat exchanger 9 is transported to the hot-end heat exchanger 8 through multiple heat pump units 1 and multiple intermediate heat exchangers 5. This allows the heat in the cold-end heat exchanger 9 to be continuously absorbed and its quality to be increased multiple times. Then, the heat is released at an ultra-high quality in the hot-end heat exchanger 8, ensuring that the heat obtained by the heating side is sufficient and can be continuously and rapidly heated. The heating side continuously outputs superheated high-temperature hot water or high-temperature steam, while the heat in the cooling side is continuously removed to obtain sufficient cooling capacity. The cooling side continuously outputs supercooled low-temperature cold water or low-temperature cold air.

[0043] Specifically, this invention addresses the problems of complex structure, insufficient reliability, low-temperature performance degradation, insufficient load adaptability, and limited hot water temperature in existing cascade heat pumps. It proposes a technical solution for a dual-source heat pump cascade high-temperature heating system, which has several technical advantages: it realizes multi-stage superposition and release of high-grade heat; through the coordinated arrangement of multiple heat pump units 1 and multiple intermediate heat exchangers 5, the low-grade heat absorbed by the cold-end heat exchanger 9 is transferred and superimposed multiple times, and finally released as ultra-high-grade heat in the hot-end heat exchanger 8, so that the heating side can stably obtain superheated high-temperature hot water or high-temperature steam, breaking through the bottleneck of limited hot water temperature in traditional cascade heat pumps.

[0044] It takes into account the dual-source characteristics of high-temperature heating and low-temperature cooling; the system is set up with heating side and cooling side at the same time, and realizes the coordinated operation of heating and cooling through the dual-loop structure of hot end heat exchanger 8 and cold end heat exchanger 9; the heating side can continuously output high-temperature hot water or steam, while the cooling side can continuously output subcooled low-temperature cold water or cold air to meet the needs of combined heating and cooling operation.

[0045] Improved performance in low-temperature environments; the cold-end heat exchanger 9 continuously introduces heat extraction medium, enabling the heat pump unit 1 to maintain continuous heat extraction and transfer in low-temperature air or water environments, reducing the performance degradation problem of traditional cascade heat pump systems under low-temperature conditions, and improving the operational stability and energy efficiency in cold regions.

[0046] The system enhances its load adaptability and reliability. Through the modular structure of the multi-stage heat pump unit 1 and the intermediate heat exchanger 5, the system can flexibly and independently adjust the operating power of the heat pump unit 1 in operation, and achieve adaptive adjustment to different load conditions. At the same time, the multi-stage heat exchange method reduces the excessively high compression ratio of the single compressor 11, avoids the risk of compressor 11 damage, and thus improves the overall reliability and service life.

[0047] In summary, through the modular structure of the multi-stage heat pump unit 1 and the intermediate heat exchanger 5, and the independent and flexible adjustment function of the module structure, the invention is not only suitable for winter heating in cold northern regions, but can also be applied to industrial steam preparation, medical disinfection, food processing and combined cooling and heating, etc., and has a wider range of application value.

[0048] As one alternative implementation method:

[0049] Regarding the specific structure and heat exchange method of the above-mentioned hot-end heat exchanger 8 and cold-end heat exchanger 9, both the hot-end heat exchanger 8 and the cold-end heat exchanger 9 are water source heat exchangers.

[0050] The heat exchanger 9 is continuously supplied with water as the heat extraction medium. By setting up a water storage tank for normal heat storage and setting up geothermal heat absorption pipelines, water is used as a transport carrier to continuously deliver heat to the cold end heat exchanger 9. Thus, the heat pump unit 1 can continuously transport heat, improve the heat extraction efficiency, and the cold water produced and discharged can be used.

[0051] The heat-absorbing medium continuously fed into the hot-end heat exchanger 8 is water. Water that absorbs heat can be continuously supplied to the hot-end heat exchanger 8 through a water supply pipeline. The water that has absorbed heat can be made into high-temperature hot water or high-temperature steam for use, thereby continuously absorbing the heat transported by the adjacent heat pump unit 1.

[0052] Furthermore, a first water control valve can be installed at the outlet end of the water supply pipeline and the inlet end of the heat absorption side of the hot-end heat exchanger 8. The opening degree of the first water control valve is controlled by the system to control the water inflow. A second water control valve is also installed at the outlet end of the heat absorption side of the hot-end heat exchanger 8. The opening degree of the first water control valve is controlled by the system to control the water outflow or steam output, thereby independently controlling the water inflow, water outflow or steam output to achieve the goal of efficient heat extraction.

[0053] In application, the cold-end heat exchanger 9 utilizes a water storage tank and geothermal heat absorption pipes as a continuous heat source, allowing water to continuously provide low-grade heat to the cold-end heat exchanger 9, avoiding the problem of insufficient heat extraction in low-temperature air environments. Furthermore, the discharged cold water can be used for process or air conditioning purposes, improving resource utilization. The hot-end heat exchanger 8 continuously inputs water to be heated through a water supply pipe, absorbs the heat transferred by the multi-stage heat pump, and outputs high-temperature hot water or steam to meet high-temperature heating demands. In addition, through the precise adjustment of the first and second water control valves, the inflow, outflow, and steam output can be independently controlled, thereby achieving an efficient and controllable heat extraction and supply process.

[0054] Furthermore, the water storage tank is equipped with a solar waste heat recovery unit or a waste heat recovery unit coupled with an industrial waste heat discharge outlet, which stores the recovered waste heat in the water storage tank for heat storage, thereby further improving the overall energy efficiency of the system operation.

[0055] Regarding the specific layout of the aforementioned heat pump unit 1 and intermediate heat exchanger 5, this embodiment is as follows: Figure 1 As shown, the heat pump unit 1 includes at least one compressor 11 and an electronic expansion valve 12; the heat pump unit 1 is provided with three heat pumps, namely a first heat pump 2, a second heat pump 3 and a third heat pump 4; the intermediate heat exchanger 5 is provided with two heat exchangers, namely a first heat exchanger 6 and a second heat exchanger 7.

[0056] Specifically, the inlet of the compressor 11 of the first heat pump 2 is connected to the outlet of the heat-releasing side of the hot-end heat exchanger 8, the outlet of the compressor 11 is connected to the inlet of the heat-absorbing side of the first heat exchanger 6, the outlet of the heat-absorbing side of the first heat exchanger 6 is connected to the electronic expansion valve 12 of the first heat pump 2, and the electronic expansion valve 12 is connected to the inlet of the heat-releasing side of the hot-end heat exchanger 8.

[0057] The inlet of the compressor 11 of the second heat pump 3 is connected to the outlet of the heat-releasing side of the first heat exchanger 6, the outlet of the compressor 11 is connected to the inlet of the heat-absorbing side of the second heat exchanger 7, the outlet of the heat-absorbing side of the second heat exchanger 7 is connected to the electronic expansion valve 12 of the second heat pump 3, and the electronic expansion valve 12 is connected to the inlet of the heat-releasing side of the first heat exchanger 6.

[0058] The inlet of the compressor 11 of the third heat pump 4 is connected to the outlet of the heat-releasing side of the second heat exchanger 7, the outlet of the compressor 11 is connected to the inlet of the heat-absorbing side of the cold end heat exchanger 9, the outlet of the heat-absorbing side of the cold end heat exchanger 9 is connected to the electronic expansion valve 12 of the third heat pump 4, and the electronic expansion valve 12 is connected to the inlet of the heat-releasing side of the second heat exchanger 7.

[0059] In application, the dual-source heat pump cascade high-temperature heating system uses three heat pump units 1 and two intermediate heat exchangers 5 to achieve a step-by-step increase in heat output. The first heat pump 2, the second heat pump 3, and the third heat pump 4 are connected in series via intermediate heat exchangers 5, progressively increasing the heat output quality of the hot-end heat exchanger 8. This allows the low-grade heat absorbed by the cold-end heat exchanger 9 to be transferred and elevated multiple times before being released centrally at the hot-end heat exchanger 8, thus ensuring a stable output of high-temperature hot water or steam even in low-temperature environments. This structure guarantees the continuous and stable operation of the heating system and solves the problem of limited high-temperature output in traditional cascade heat pumps.

[0060] In addition, the heat pump unit 1 can be expanded to four or more stages in series to further increase the heating temperature at the hot end and adapt to industrial steam conditions with higher temperature requirements.

[0061] Furthermore, low-pressure units 13 are provided between the inlet of the compressor 11 of the first heat pump 2 and the outlet of the heat-releasing side of the hot-end heat exchanger 8, between the inlet of the compressor 11 of the second heat pump 3 and the outlet of the heat-releasing side of the first heat exchanger 6, and between the inlet of the compressor 11 of the third heat pump 4 and the outlet of the heat-releasing side of the second heat exchanger 7. The low-pressure unit 13 includes a first pressure sensor and a first valve. The first pressure sensor monitors the pressure of the low-pressure circuit of the compressor 11 of the current heat pump unit 1, and controls the opening of the first valve based on the heat exchange demand of the current heat pump unit 1, so as to realize independent flow regulation of the low-pressure circuits of the first heat pump 2, the second heat pump 3 and the third heat pump 4.

[0062] When applied, the low-pressure unit 13 uses a combination of a first pressure sensor and a first valve to monitor the low-pressure circuit pressure of each heat pump compressor 11 in real time, and controls the valve opening according to the operating requirements to achieve independent adjustment of the low-pressure circuit flow. This technical structure ensures that different heat pump units 1 can obtain suitable return gas pressure under different load conditions, avoids the problem of unstable operation of compressor 11 caused by excessively low pressure, and improves the reliability of system operation.

[0063] In addition, the low-voltage unit 13 further improves energy efficiency by combining electronic throttling devices and intelligent control algorithms to achieve dynamic adjustment based on load forecasting.

[0064] Furthermore, high-pressure units 14 are provided between the outlet of the compressor 11 of the first heat pump 2 and the inlet of the heat absorption side of the first heat exchanger 6, between the outlet of the compressor 11 of the second heat pump 3 and the inlet of the heat absorption side of the second heat exchanger 7, and between the outlet of the compressor 11 of the third heat pump 4 and the inlet of the heat absorption side of the cold end heat exchanger 9. The high-pressure unit 14 includes a second pressure sensor and a second valve. The pressure of the high-pressure circuit of the compressor 11 of the current heat pump unit 1 is monitored by the second pressure sensor, and the opening degree of the second valve is controlled by comprehensively considering the heat exchange demand of the current heat pump unit 1, so as to realize independent flow regulation of the high-pressure circuits of the first heat pump 2, the second heat pump 3 and the third heat pump 4.

[0065] In application, the high-pressure unit 14 monitors the high-pressure circuit pressure of each heat pump compressor 11 in real time through the combination of the second pressure sensor and the second valve, and adjusts the valve opening according to the heat exchange requirements to achieve independent control of the high-pressure flow. This structure avoids the problem of excessive pressure in the high-pressure circuit of the compressor 11 due to uneven load under different load conditions of different heat pump units 1, and improves the heat exchange stability and the service life of the compressor 11.

[0066] In addition, temperature sensors are added to the heat release side of the hot end heat exchanger 8 and the heat release side of the intermediate heat exchanger 5. The temperature sensor data is connected to the system and controlled by the system linkage high pressure unit 14 to achieve pressure-temperature dual closed-loop control, ensuring that the temperature on the heat supply and heat release sides is accurately controllable and further improving the adaptability to complex heating conditions.

[0067] Regarding the safety structure of the aforementioned heat pump unit 1, this implementation is, for example... Figure 1As shown, exhaust valves 15 are provided between the outlet of the compressor 11 of the first heat pump 2 and the high-pressure unit 14, between the outlet of the compressor 11 of the second heat pump 3 and the high-pressure unit 14, and between the outlet of the compressor 11 of the third heat pump 4 and the high-pressure unit 14. When the pressure in the high-pressure circuit of the compressor 11 of the current heat pump unit 1 is too high, and the pressure between the outlet of the compressor 11 and the high-pressure unit 14 is still too high after controlling the opening of the first valve and the second valve, the exhaust valve 15 is used to exhaust pressure and control the pressure of the current pipeline to return to the threshold range.

[0068] When the high pressure circuit is detected to be abnormally high and cannot be relieved by valve adjustment, the exhaust valve 15 will automatically release pressure to ensure that the pipeline pressure drops back to the threshold range, thereby preventing damage to the compressor 11 and the heat exchanger and improving the safety and reliability of the system operation.

[0069] In addition, such as Figure 2 As shown, the exhaust valve 15 has a dual-loop redundant valve group structure to prevent the failure of the single exhaust valve 15 and further improve the safety redundancy of the dual-source heat pump cascade high-temperature heating system.

[0070] To achieve efficient heat absorption and controllable heat extraction, improve energy efficiency, and realize energy conservation and emission reduction, this implementation, for example... Figure 1 As shown, the compressor 11 of the first heat pump 2 is a variable frequency compressor 11, while the compressors 11 of the second heat pump 3 and the third heat pump 4 are both fixed frequency compressors 11. By setting the two fixed frequency compressors 11 of the second heat pump 3 and the third heat pump 4 to be arranged near the cooling side and the variable frequency compressor 11 of the first heat pump 2 to be arranged near the heating side, the cooling side can continuously supply cold water or cold air in summer and continuously supply heat in winter. The cold water or cold air produced is directly discharged or the heat is transported, so that the heating side can continuously provide high temperature hot water or high temperature steam in summer or winter.

[0071] In application, the compressor 11 of the first heat pump 2 is a variable frequency compressor 11, which is located near the heating side so as to flexibly adjust the heating capacity according to the demand of the heat end; the second heat pump 3 and the third heat pump 4 are fixed frequency compressors 11, which are located near the cooling side so as to stably transport low-grade heat. This arrangement allows the cooling side to continuously supply cold water or cold air in summer, and to transport heat and directly discharge cold water or cold air in winter, thereby ensuring that the heating side can continuously obtain high-temperature hot water or steam throughout the year, and realize the efficient operation of combined cooling and heating.

[0072] In addition, the type of compressor 11 mentioned above can be changed to a full variable frequency combination according to application requirements. Intelligent control algorithms can be set in the system controller to achieve optimal energy efficiency scheduling in conjunction with artificial intelligence control strategies.

[0073] Regarding the specific structure of the efficient heat supply source on the cooling side mentioned above, this implementation is as follows: Figure 3 As shown, the cooling side is equipped with a cooling capacity intake end 91 and a geothermal heat exchange end 93, and water is introduced as the heat exchange medium. The cooling capacity intake end 91 is located on the outlet side of the cold end heat exchanger 9 and is used to release cooling capacity. The geothermal heat exchange end 93 is located on the inlet side of the cold end heat exchanger 9 and is used to transport geothermal heat. The inlet side of the cold end heat exchanger 9 is equipped with a water source compensation port 92 for replenishing the heat exchange water and providing additional heat. The cooling capacity intake end 91 is provided with a cold water intake unit 911 and a cold water discharge unit 912 in sequence along the water outlet direction.

[0074] In application, the cooling side uses water as a medium to exchange heat by setting up a cooling capacity intake end 91 and a geothermal heat exchange end 93. The cooling capacity intake end 91 is responsible for discharging low-temperature cold water or cold air to meet industrial refrigeration or air conditioning needs; the geothermal heat exchange end 93 introduces geothermal energy into the cold end heat exchanger 9, improving the stability of the low-grade heat source.

[0075] The supplementary water supply through the water source compensation port 92 not only ensures a stable amount of hot water for exchange, but also introduces an additional heat source, enhancing the continuity and adjustability of the system operation.

[0076] In areas with low temperatures, the heat source can be switched between the water source compensation port 92 and the geothermal heat exchange end 93 to avoid overcooling and freezing caused by using the same heating method for a long time. This prevents the heat exchange efficiency on the cooling side from decreasing, which would reduce the overall energy efficiency of the heating system and affect the heating effect.

[0077] In addition, the cooling side can be further connected to rivers and reservoirs to achieve multi-source heat extraction across seasons and regions, thereby improving the system's adaptability.

[0078] The second embodiment of the dual-source heat pump cascade high-temperature heating system differs from the first embodiment in that the cold water intake unit 911 is equipped with a water pipe and cooling fins; the cold water discharge unit 912 is equipped with a drain port and heat absorption fins; the water outlet pipe of the water outlet port of the heat absorption fins is connected to the water inlet side between the geothermal heat exchange end 93 and the cold end heat exchanger 9, for directly inputting the heat absorbed from the air into the cold end heat exchanger 9.

[0079] In application, the cold water intake unit 911 is used in conjunction with the cooling fins through a water pipe to achieve the exchange of sensible and latent heat on the air side; the cold water discharge unit 912 is used in conjunction with the heat absorption fins through a drain port to smoothly discharge low-temperature cold water and absorb heat from the surrounding air at the same time.

[0080] Specifically, the water outlet pipe of the heat-absorbing fins is directly connected between the geothermal heat exchange end 93 and the water inlet side of the cold end heat exchanger 9, so that the low-grade heat obtained from the air can be quickly input to the cold end heat exchanger 9 without additional circulation; this technical structure enables the cold end heat exchanger 9 to receive heat from both geothermal and air heat sources at the same time, enhancing the dual-source heating capability and further improving heat extraction efficiency.

[0081] By combining air-side heat absorption and geothermal-side heat absorption, the problem of insufficient single low-temperature heat source is effectively solved, enabling the system to maintain a stable heat transport and lifting process under low-temperature conditions, as well as maintain efficient heat exchange, ensuring a continuous output of high-temperature hot water or steam at the heating end.

[0082] In addition, the cooling fins and heat-absorbing fins can be coated with hydrophilic coatings or nano-reinforced surface treatments to improve air heat exchange efficiency and reduce frost formation. Meanwhile, the bridging water outlet pipe can be equipped with bypass valves or energy storage buffer tanks. By setting a heat source supply regulation algorithm in the system, dynamic adjustment of different heat source input ratios can be achieved, thereby further improving the adaptive performance of the dual-source heat pump cascade high-temperature heating system under different climate and load conditions.

[0083] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described.

Claims

1. A dual-source heat pump cascade high-temperature heating system, characterized in that, it comprises a plurality of heat pump units and a plurality of intermediate heat exchangers; a hot-end heat exchanger is arranged on the heating side, and a cold-end heat exchanger is arranged on the cooling side; the plurality of heat pump units are arranged between the hot-end heat exchanger and the cold-end heat exchanger, and the intermediate heat exchangers are arranged between two adjacent heat pump units; the cold-end heat exchanger continuously inputs a heat-removing medium, which is used to continuously carry heat by the adjacent heat pump units; the hot-end heat exchanger continuously inputs a heat-absorbing medium, which is used to continuously absorb the heat carried by the adjacent heat pump units; the heat absorbed by the cold-end heat exchanger is carried to the hot-end heat exchanger through the plurality of heat pump units and the plurality of intermediate heat exchangers, so that the heat of the cold-end heat exchanger is continuously absorbed and stacked multiple times to improve the heat grade, and then released at the hot-end heat exchanger at an ultra-high grade, so that the heat obtained by the heating side is sufficient and can be continuously and quickly heated, and the heating side continuously outputs superheated high-temperature hot water or high-temperature steam, so that the cooling side continuously removes heat to obtain sufficient cold, and the cooling side continuously outputs supercooled low-temperature cold water or low-temperature cold air; the heat pump unit comprises at least one compressor and an electronic expansion valve; the heat pump unit is provided with three heat pumps, namely a first heat pump, a second heat pump and a third heat pump; the intermediate heat exchanger is provided with two heat exchangers, namely a first heat exchanger and a second heat exchanger; the inlet end of the compressor of the first heat pump is connected to the outlet end of the heat-releasing side of the hot-end heat exchanger, the outlet end of the heat-absorbing side of the first heat exchanger is connected to the inlet end of the compressor, the outlet end of the heat-absorbing side of the first heat exchanger is connected to the electronic expansion valve of the first heat pump, and the inlet end of the heat-releasing side of the hot-end heat exchanger is connected to the electronic expansion valve; the inlet end of the compressor of the second heat pump is connected to the outlet end of the heat-releasing side of the first heat exchanger, the outlet end of the heat-absorbing side of the second heat exchanger is connected to the inlet end of the compressor, the outlet end of the heat-absorbing side of the second heat exchanger is connected to the electronic expansion valve of the second heat pump, and the inlet end of the heat-releasing side of the first heat exchanger is connected to the electronic expansion valve; the inlet end of the compressor of the third heat pump is connected to the outlet end of the heat-releasing side of the second heat exchanger, the outlet end of the heat-absorbing side of the cold-end heat exchanger is connected to the inlet end of the compressor, the outlet end of the heat-absorbing side of the cold-end heat exchanger is connected to the electronic expansion valve of the third heat pump, and the inlet end of the heat-releasing side of the second heat exchanger is connected to the electronic expansion valve; low-pressure units are arranged between the inlet end of the compressor of the first heat pump and the outlet end of the heat-releasing side of the hot-end heat exchanger, between the inlet end of the compressor of the second heat pump and the outlet end of the heat-releasing side of the first heat exchanger, and between the inlet end of the compressor of the third heat pump and the outlet end of the heat-releasing side of the second heat exchanger; the low-pressure unit comprises a first pressure sensor and a first valve, the pressure of the low-pressure circuit of the compressor of the heat pump unit is monitored by the first pressure sensor, the opening degree of the first valve is controlled according to the heat exchange demand of the heat pump unit, and independent flow regulation of the low-pressure circuits of the first heat pump, the second heat pump and the third heat pump is realized. A high-pressure unit is arranged between the outlet end of the compressor of the first heat pump and the inlet end of the heat-absorbing side of the first heat exchanger, between the outlet end of the compressor of the second heat pump and the inlet end of the heat-absorbing side of the second heat exchanger, and between the outlet end of the compressor of the third heat pump and the inlet end of the heat-absorbing side of the cold-end heat exchanger; the high-pressure unit comprises a second pressure sensor and a second valve; the pressure of the high-pressure circuit of the compressor of the heat pump unit is monitored by the second pressure sensor; the opening degree of the second valve is controlled according to the heat exchange demand of the heat pump unit, so as to realize independent flow regulation of the high-pressure circuits of the first heat pump, the second heat pump and the third heat pump. An exhaust valve is arranged between the outlet end of the compressor of the first heat pump and the high-pressure unit, between the outlet end of the compressor of the second heat pump and the high-pressure unit, and between the outlet end of the compressor of the third heat pump and the high-pressure unit; when the pressure of the high-pressure circuit of the compressor of the heat pump unit is too high and the opening degrees of the first valve and the second valve are controlled, the pressure between the outlet end of the compressor and the high-pressure unit is still too high, the exhaust valve is used for exhaust pressure relief to control the current pipeline pressure to be within the threshold range. The compressor of the first heat pump is a variable-frequency compressor, and the compressors of the second heat pump and the third heat pump are fixed-frequency compressors; the two fixed-frequency compressors of the second heat pump and the third heat pump are arranged adjacent to the cold supply side, and the variable-frequency compressor of the first heat pump is arranged adjacent to the heat supply side, so that the cold supply side can continuously supply cold water or cold air in summer and continuously supply heat in winter, and the cold water or cold air produced is directly discharged or carries heat, so that the heat supply side can continuously supply high-temperature hot water or high-temperature steam in summer or winter.

2. The dual-source heat pump cascade high-temperature heating system according to claim 1, wherein the cold supply side is provided with a cold quantity taking and using end and a geothermal heat exchange end, and water is introduced as a heat exchange medium. The cold quantity taking and using end is arranged at the water outlet side of the cold-end heat exchanger and is used for discharging cold quantity. The geothermal heat exchange end is arranged at the water inlet side of the cold-end heat exchanger and is used for carrying geothermal heat. The water inlet side of the cold-end heat exchanger is provided with a water source compensation port for supplementing water for heat exchange and providing additional heat. The cold quantity taking and using end is sequentially provided with a cold water taking unit and a cold water discharging unit in the water outlet direction.

3. The dual-source heat pump cascade high-temperature heating system according to claim 2, wherein the cold water taking unit is provided with a water taking pipeline and a refrigeration fin, and the cold water discharging unit is provided with a water discharging port and a heat absorbing fin. The water outlet port of the heat absorbing fin is connected to the water inlet side of the cold-end heat exchanger through a water pipe, and is used for directly inputting heat absorbed from air into the cold-end heat exchanger. The heat-end heat exchanger and the cold-end heat exchanger are both water source heat exchangers. ​ 4. The dual-source heat pump cascade high temperature heating system according to any of claims 1 or 2, characterized in that, ​

Images