Multi-grade heat source heat supply system and control method thereof

Abstract

The invention discloses a multi-grade heat source heat supply system which is characterized in that a first control assembly is arranged on a path from a high-temperature heat source pipeline to a heat pump machine through a third-stage well group, and a second control assembly is arranged on a path from a medium-temperature heat source pipeline to the heat pump machine through a second-stage well group; and the third control assembly is arranged on a path from the low-temperature heat source pipeline to the heat pump machine through the parallel well group. According to the temperature of the external heat source and user requirements, the first control assembly, the second control assembly and the third control assembly can be controlled to utilize heat sources of different temperature levels in a grading mode, the system can utilize energy more efficiently, and energy waste is reduced. Due to the arrangement of the parallel well groups, the redundancy of the system is increased, even if part of well paths in the third-level well group or the second-level well group break down, the system can still operate normally, and the overall reliability of the system is improved. The invention further provides a control method applied to the heat supply system so as to improve the efficiency of the heat supply system.

Description

Technical Field

[0001] The present application relates to the technical field of energy conservation and environmental protection, and in particular to a multi-grade heat source heating system and a control method thereof. Background Art

[0002] In recent years, with the continuous advancement of energy-saving technology, some low-grade waste heat recovery and utilization methods and devices have begun to appear.

[0003] However, there are many sources of heat now, such as solar energy, industrial waste heat, geothermal energy, biomass energy, etc. Due to the wide variety of heat sources, if it is only used for heating, the waste heat will be unusable during the non-heating period; if it is only used for power generation, the energy utilization efficiency is not high; and by adding a heat pump to improve the quality of waste heat, it not only consumes some high-quality electricity, but also increases the cost of the system.

[0004] Therefore, there is an urgent need for a heating system to solve the problem of single waste heat source and form and to improve energy utilization. Summary of the invention

[0005] The embodiment of the present application provides a heating system for multi-grade heat sources, aiming to provide different sources and pathways for waste heat sources, while improving energy utilization efficiency, so as to achieve the purpose of improving the quality of waste heat.

[0006] To achieve the above objectives, this application provides the following technical solutions: A multi-grade heat source heating system, comprising a heat pump, a high-temperature heat source pipeline, a medium-temperature heat source pipeline, a low-temperature heat source pipeline, a three-level well group, a two-level well group and a parallel well group, a first control component, a second control component and a third control component; One working end of the heat pump is connected to an external user terminal, and the other working end thereof is connected to a working end of the third-level well group, a working end of the second-level well group, and a working end of the parallel well group; The other working end of the third-level well group is connected to a working end of the high-temperature heat source pipeline; The other working end of the secondary well group is connected to a working end of the medium-temperature heat source pipeline; The other working end of the parallel well group is connected to a working end of the low-temperature heat source pipeline; Each well path of the parallel well group is connected in parallel with each well path of the third-level well group and each well path of the second-level well group; The other working end of the high-temperature heat source pipeline is connected to the external high-temperature environment pipe; The other working end of the medium-temperature heat source pipeline is connected to the external medium-temperature environment pipe; The other working end of the low-temperature heat source pipeline is connected to the external low-temperature environment pipe; The first control component is arranged on the path from the high-temperature heat source pipeline through the three-level well group to the heat pump machine, and can switch the energy supply state of the high-temperature heat source pipeline and the heat pump machine to the three-level well group; The second control component is arranged on the path from the medium-temperature heat source pipeline through the secondary well group to the heat pump machine, and can switch the energy supply state of the medium-temperature heat source pipeline and the heat pump machine to the tertiary well group; The third control component is arranged on the path from the low-temperature heat source pipeline to the heat pump through the parallel well group, and can switch the energy supply state of the low-temperature heat source pipeline and the heat pump to the parallel well group.

[0007] Further, the first control assembly includes a first plate converter, a first valve, a third valve and two first water pumps; The first plate exchanger is connected in series on the path of the high-temperature heat source pipeline leading to the third-level well group; The first valve is connected to the return water path of the high-temperature heat source pipeline leading to the first plate exchanger; The third valve is connected to the water supply path from the third-level well group to the heat pump; A first water pump is connected to a return water path from the first valve to the first plate exchanger, and another first water pump is connected to a return water path from the three-level well group to the heat pump.

[0008] Further, the second control assembly includes a second plate exchanger, a second valve, a fourth valve, and two second water pumps; The second plate exchanger is connected in series on the path of the medium-temperature heat source pipeline leading to the secondary well group; The second valve is connected to the return water path of the medium-temperature heat source pipeline leading to the second plate exchanger; The fourth valve is connected to the water supply path from the secondary well group to the heat pump; A second water pump is connected to the return water path of the medium-temperature heat source pipeline leading to the second plate exchanger, and another second water pump is connected to the return water path of the secondary well group leading to the heat pump.

[0009] Furthermore, the third control component includes a third plate exchanger and two third water pumps; the third plate exchanger is connected in series on the path from the low-temperature heat source pipeline to the parallel well group; one third water pump is connected to the return water path from the low-temperature heat source pipeline to the third plate exchanger, and the other third water pump is connected to the return water path from the parallel well group to the heat pump.

[0010] Further, a compensation unit is included; One working end of the compensation unit is connected in parallel to the path from the tertiary well group, the secondary well group, and the parallel well group to the heat pump, and the other working end is connected to the external heat source environment, which can compensate for the energy supply status of the tertiary well group, the secondary well group, and the parallel well group to the heat pump; The compensation unit includes a fourth plate exchanger and two fourth water pumps; The fourth plate exchanger is arranged on the path from the external heat source environment to the third-level well group, the second-level well group, and the parallel well group to the heat pump; A fourth water pump is connected to the return water path from the external heat source environment to the fourth plate exchanger, and another fourth water pump is connected to the path from the fourth plate exchanger to the third well group, the second well group, the parallel well group and the heat pump.

[0011] Furthermore, the first valve, the third valve, the second valve and the fourth valve are all three-way valves.

[0012] The present application also provides a control method for a multi-grade heat source heating system, which uses the above heating system and further includes the following steps: During heat storage, in the high-temperature heat source pipeline path, if the return water temperature is greater than or equal to 40°C, the first valve is opened to allow hot water at this temperature to enter the water supply path of the low-temperature heat source pipeline; if the return water temperature is less than 40°C, the water is directly returned to the high-temperature heat source pipeline, and passes through the first plate exchanger for secondary heat exchange again until the temperature reaches the range of 80°C-90°C, and then stored in the tertiary well group. When the return water temperature of the tertiary well group reaches 55°C, the heat storage is stopped; In the medium-temperature heat source pipeline path, if the return water temperature is less than 40°C, open the second valve to allow hot water at this temperature to enter the water supply path of the medium-temperature heat source pipeline, and perform secondary heat exchange through the second plate exchanger until the hot water reaches a temperature range of greater than or equal to 57°C and less than 87°C and is stored in the secondary well group. When the return water temperature of the secondary well group reaches 42°C, stop heat storage; In the low-temperature heat source pipeline path, if the return water temperature is less than 30°C, open the second valve to allow hot water at this temperature to enter the water supply path of the low-temperature heat source pipeline, and perform secondary heat exchange through the third plate exchanger until the hot water reaches a temperature range of greater than 40°C and less than 57°C and is stored in the parallel well group. When the return water temperature of the parallel well group reaches 32°C, stop heat storage; When releasing heat, the third valve is opened, and the high-temperature water of the three-level well group greater than or equal to 48°C enters the fourth plate exchanger, and the fourth plate exchanger converts the high-temperature water of the three-level well group into hot water with a temperature of 45°C and supplies water to the user terminal. When the high-temperature water of the three-level well group is less than 48°C, the water of this temperature is output to the heat pump machine through the first water pump to provide 55°C hot water for the user terminal; Open the fourth valve, and water with a temperature greater than or equal to 48°C in the secondary well group is output to the fourth plate exchanger through the second water pump, and hot water with a temperature less than 48°C enters the heat pump, and the hot water in the parallel well group enters the heat pump through the third water pump.

[0013] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages: The system of the present application can flexibly switch different working modes by controlling the first control component, the second control component, and the third control component according to the temperature of the external heat source and user needs. For example, in high-temperature seasons or regions, high-temperature heat sources can be mainly used; in low-temperature seasons or regions, heat pumps can be relied on more to increase heat. By utilizing heat sources of different temperature levels in a graded manner, the system can utilize energy more efficiently. High-temperature heat sources are used for high-grade needs, and low-temperature heat sources are used for low-grade needs, which reduces energy waste while reducing dependence on fossil energy and carbon emissions. The setting of parallel well groups increases the redundancy of the system. Even if part of the well lines in the third-level well group or the second-level well group fail, the system can still operate normally, improving the overall reliability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments of the present application or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0015] Figure 1 A schematic diagram of the system provided in the embodiment of the present application; Figure 2 A schematic diagram of the structure of a single well group well circuit and each heat source pipeline in a connected state provided in an embodiment of the present application; Figure 3 A schematic diagram of the distribution of the pipe group connection provided in the embodiment of the present application; Figure 4 A schematic diagram of the parallel connection of two well paths of a single well group provided in an embodiment of the present application; Figure 5 A schematic diagram of three well paths in parallel in a single well group provided in an embodiment of the present application; Figure 6 A schematic diagram of a system combining a preheating well group provided in an embodiment of the present application; Figure 7 A schematic diagram of the well path zoning structure of a three-stage preheating well group, a two-stage preheating well group and a parallel well group provided in an embodiment of the present application.

[0016] Icons: 1-heat pump; 2-high-temperature heat source pipeline; 3-medium-temperature heat source pipeline; 4-low-temperature heat source pipeline; 5-third-level well group; 51-third-level well road unit; 511-inclined well road; 512-vertical well road; 52-third-level preheating well group; 6-second-level well group; 61-second-level well road unit; 611-second-level well road; 62-second-level preheating well group; 7-parallel well group; 71-parallel well road; 72-parallel preheating well group; 10-first plate exchanger; 11-first valve; 12-third valve; 13-first water pump; 20-second plate exchanger; 21-second valve; 22-fourth valve; 23-second water pump; 30-third plate exchanger; 31-third water pump; 40-fourth plate exchanger; 41-fourth water pump. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0018] In the description of the embodiments of the present application, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limitations on the present application. The terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. In addition, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0019] Combination Figures 1 to 7As shown, a multi-grade heat source heating system includes a heat pump 1, a high-temperature heat source pipeline 2, a medium-temperature heat source pipeline 3, a low-temperature heat source pipeline 4, a tertiary well group 5, a secondary well group 6 and a parallel well group 7, a first control component, a second control component and a third control component; one working end of the heat pump 1 is connected to an external user terminal, and the other working end thereof is connected to a working end of the tertiary well group 5, a working end of the secondary well group 6, and a working end pipe of the parallel well group 7; the other working end of the tertiary well group 5 is connected to a working end pipe of the high-temperature heat source pipeline 2; the other working end of the secondary well group 6 is connected to a working end pipe of the medium-temperature heat source pipeline 3; the other working end of the parallel well group 7 is connected to a working end pipe of the low-temperature heat source pipeline 4; each well path of the parallel well group 7 is connected to each well path of the tertiary well group 5, each well path of the secondary well group 6 The wells are connected in parallel; the other working end of the high-temperature heat source pipeline 2 is connected to the external high-temperature environment pipe; the other working end of the medium-temperature heat source pipeline 3 is connected to the external medium-temperature environment pipe; the other working end of the low-temperature heat source pipeline 4 is connected to the external low-temperature environment pipe; the first control component is arranged on the path from the high-temperature heat source pipeline 2 to the heat pump 1 via the three-level well group 5, and can switch the energy supply state of the high-temperature heat source pipeline 2 and the heat pump 1 to the three-level well group 5; the second control component is arranged on the path from the medium-temperature heat source pipeline 3 to the heat pump 1 via the two-level well group 6, and can switch the energy supply state of the medium-temperature heat source pipeline 3 and the heat pump 1 to the three-level well group 5; the third control component is arranged on the path from the low-temperature heat source pipeline 4 to the heat pump 1 via the parallel well group 7, and can switch the energy supply state of the low-temperature heat source pipeline 4 and the heat pump 1 to the parallel well group 7.

[0020] In the above scheme, the high-temperature heat source pipeline 2, the medium-temperature heat source pipeline 3 and the low-temperature heat source pipeline 4 are respectively connected to the external high-temperature, medium-temperature and low-temperature environments to provide heat sources of different temperature levels for the system. The tertiary well group 5, the secondary well group 6 and the parallel well group 7 are respectively connected to the high-temperature heat source pipeline 2, the medium-temperature heat source pipeline 3 and the low-temperature heat source pipeline 4 for extracting and storing heat sources. The first control component is located between the high-temperature heat source pipeline 2 and the tertiary well group 5, and is used to switch the energy supply state of the high-temperature heat source pipeline 2 and the heat pump 1 to the tertiary well group 5. When the heat source of the high-temperature heat source pipeline 2 is sufficient, the energy supply of the heat pump 1 to the tertiary well group 5 can be turned off, and the high-temperature heat source can be directly used. The second control component is located between the medium-temperature heat source pipeline 3 and the secondary well group 6. When the heat source in the medium-temperature heat source pipeline 3 is sufficient, the energy supply of the heat pump 1 to the secondary well group 6 can be turned off, and the medium-temperature heat source can be directly used. The third control component is located between the low temperature heat source pipeline 4 and the parallel well group 7, and is used to switch the energy supply state of the low temperature heat source pipeline 4 and the heat pump machine 1 to the parallel well group 7. When the low temperature heat source is sufficient, the low temperature heat source can be used preferentially.

[0021] It should be noted that the high temperature heat source pipeline 2 and the medium temperature heat source pipeline 3 in the present application are both series wells. Each well of the parallel well group 7 is connected in parallel with each well of the high temperature heat source pipeline 2 and the medium temperature heat source pipeline 3.

[0022] The system of the present application can flexibly switch different working modes by controlling the first control component, the second control component, and the third control component according to the temperature of the external heat source and user needs. For example, in high-temperature seasons or regions, high-temperature heat sources can be mainly used; in low-temperature seasons or regions, more reliance can be placed on the heat pump 1 to increase heat. By utilizing heat sources of different temperature levels in a graded manner, the system can utilize energy more efficiently. High-temperature heat sources are used for high-grade needs, and low-temperature heat sources are used for low-grade needs, which reduces energy waste while reducing dependence on fossil energy and carbon emissions. The setting of the parallel well group 7 increases the redundancy of the system. Even if part of the well lines in the tertiary well group 5 or the secondary well group 6 fail, the system can still operate normally, thereby improving the overall reliability of the system.

[0023] like Figure 3-Figure 5 As shown, the parallel buried pipe group is distributed around the buried pipe group in the series area. The edge area in the figure is the parallel well group 7, the middle connecting part is the series area, the third-level well group 5 area is set at the most central position, and the second-level well group 6 is set around the third-level well group 5. A 20cm thick XPS insulation layer is set on the top of the buried pipe group, and HDPE film waterproofing is done; no insulation and waterproofing treatment is done around it.

[0024] The three-level well path unit 51 includes an inclined well path 511 and two vertical well paths 512. Each inclined well path 511 is composed of three well paths arranged in an inclined path and connected in series; each vertical well path 512 is composed of three well paths arranged in a right angle path and connected in series; The purpose of such arrangement is that the vertical well path 512 can form a cyclic heat exchange radiation field with the inclined well path 511, thereby reducing the heat dissipation of the three-level well group 5 and improving the heat storage capacity of the three-level well group 5; The secondary well group 6 includes a plurality of secondary well path units 61 evenly arranged around the tertiary well group 5, each secondary well path unit 61 includes two secondary well paths 611 that are inclined from outside to inside and connected in series, and the inclination direction of the secondary well path 611 is consistent with the inclination direction of the inclined well path 511 in the adjacent tertiary well path unit 51.

[0025] The purpose of this arrangement is to allow the heat radiation field in the secondary well group 6 to partially overlap with the heat radiation field in the tertiary well group 5, which can not only obtain a better heat exchange temperature difference, but also reduce the heat dissipation effect of the secondary well group 6; The parallel well group 7 includes parallel well paths 71 that are evenly arranged on the outside of the secondary well group 6 and correspond one-to-one to the secondary well paths 611 on the outside of the secondary well group 6. Each parallel well path 71 is connected in parallel with the secondary well path 611, exchanges heat with the secondary well group 6 and stores heat in the parallel well group 7. The parallel well group 7 and the secondary well group 6 and the tertiary well group 5 form a thermal radiation field with a stepped temperature difference, thereby reducing the heat loss generated when the heating system is working and improving the energy utilization rate of the heating system when working.

[0026] The working principle of the pipe group system is as follows: when storing heat, heat is preferentially stored in the buried pipe group in the series area (tertiary well group 5 and secondary well group 6), and the flow direction of the circulating water is from inside to outside. When the heat exchange capacity of the series area (tertiary well group 5 and secondary well group 6) is insufficient, the heat is stored in the peripheral parallel well group 7, so that a stepped soil temperature field with high middle temperature and low surrounding temperature is formed at the end of heat storage, reducing heat loss. When extracting heat, the model can realize a variety of heat extraction methods. At the end of heat storage, the tertiary well group 5 and the secondary well group 6 form a higher temperature core. In order to obtain a higher heat exchange temperature difference, the flow direction of the circulating water when extracting heat from the tertiary well group 5 and the secondary well group 6 is opposite to that during heat storage. When the heat exchange temperature difference is large enough to meet the direct heating demand, this part of the heat is used for direct heating, and at this time, the power consumption of the system comes entirely from the water pump, which reduces the energy consumption compared with the activation of the heat pump 1.

[0027] The first control component includes a first plate exchanger 10, a first valve 11, a third valve 12 and two first water pumps 13; the first plate exchanger 10 is connected in series on the path from the high-temperature heat source pipeline 2 to the tertiary well group 5; the first valve 11 is connected to the return water path from the high-temperature heat source pipeline 2 to the first plate exchanger 10; the third valve 12 is connected to the water supply path from the tertiary well group 5 to the heat pump 1; one first water pump 13 is connected to the return water path from the first valve 11 to the first plate exchanger 10, and the other first water pump 13 is connected to the return water path from the tertiary well group 5 to the heat pump 1.

[0028] In the above scheme, the first plate exchanger 10 is connected in series on the path from the high-temperature heat source pipeline 2 to the tertiary well group 5, so that the heat in the high-temperature heat source pipeline 2 can be transferred to the medium (such as water or other heat carrier) in the tertiary well group 5 through the plate exchanger, and the first valve 11 is connected to the return water path from the high-temperature heat source pipeline 2 to the first plate exchanger 10 to control the flow of heat in the high-temperature heat source pipeline 2. When it is necessary to use the high-temperature heat source to heat the tertiary well group 5, the valve is opened to allow heat to be transferred through the plate exchanger; when it is not necessary, the valve is closed to cut off the transfer of heat. The third valve 12 is connected to the water supply path from the tertiary well group 5 to the heat pump 1, and is used to control whether the heat in the tertiary well group 5 is directly supplied to the heat pump 1. If the high-temperature heat source is sufficient to directly meet the user's needs, or for energy saving considerations, the third valve 12 is closed to reduce the operating time of the heat pump 1. The two first water pumps 13 are respectively connected to the return water path from the first valve 11 to the first plate exchanger 10 and the return water path from the tertiary well group 5 to the heat pump 1, ensuring that the medium in the heat transfer path can flow continuously and stably.

[0029] In the present application, the first plate exchanger 10 reduces the loss of heat flow in the high-temperature heat source pipeline 2 during the transfer process. The setting of the first valve 11 and the third valve 12 enables the system to be flexibly adjusted according to changes in the external heat source and user needs. For example, when the high-temperature heat source is sufficient, the heat pump 1 can be turned off to supply energy to the three-level well group 5 and directly use the high-temperature heat source; when the demand changes, the valve opening can be adjusted to change the heat transfer rate. By reasonably adjusting the opening and closing states of the first valve 11 and the third valve 12 and the operating state of the first water pump 13, the system can reduce energy consumption while ensuring the quality of heating.

[0030] The second control component includes a second plate exchanger 20, a second valve 21, a fourth valve 22, and two second water pumps 23; the second plate exchanger 20 is connected in series on the path from the medium-temperature heat source pipeline 3 to the secondary well group 6; the second valve 21 is connected to the return water path from the medium-temperature heat source pipeline 3 to the second plate exchanger 20; the fourth valve 22 is connected to the water supply path from the secondary well group 6 to the heat pump 1; one second water pump 23 is connected to the return water path from the medium-temperature heat source pipeline 3 to the second plate exchanger 20, and another second water pump 23 is connected to the return water path from the secondary well group 6 to the heat pump 1.

[0031] In the above scheme, the second plate exchanger 20 is connected in series on the path from the medium-temperature heat source pipeline 3 to the secondary well group 6. The heat in the medium-temperature heat source pipeline 3 can be transferred to the medium (such as water or other heat carrier) in the secondary well group 6 through the second plate exchanger 20. The second valve 21 is connected to the return water path from the medium-temperature heat source pipeline 3 to the second plate exchanger 20 to control the flow of heat in the medium-temperature heat source pipeline 3. When the medium-temperature heat source is needed to heat the secondary well group 6, the second valve 21 is opened to allow heat to be transferred through the second plate exchanger 20; when the medium-temperature heat source is not needed to heat the secondary well group 6, the second valve 21 is closed to cut off the transfer of heat. The fourth valve 22 is connected to the water supply path from the secondary well group 6 to the heat pump 1, and is used to control whether the heat in the secondary well group 6 is directly supplied to the heat pump 1. If the medium-temperature heat source is sufficient to directly meet the user's needs or for energy saving considerations, the second valve 21 will be closed to reduce the operating time of the heat pump 1. The two second water pumps 23 are respectively connected to the return water path from the medium-temperature heat source pipeline 3 to the second plate exchanger 20, and the return water path from the secondary well group 6 to the heat pump 1, to ensure that the medium in the heat transfer path can flow continuously and stably.

[0032] The present application realizes efficient heat transfer through the second plate exchanger 20, and the setting of the second valve 21 and the fourth valve 22 enables the system to be flexibly adjusted according to the changes in the external heat source and the needs of the user. For example, when the medium-temperature heat source is sufficient, the energy supply of the heat pump 1 to the secondary well group 6 can be turned off, and the medium-temperature heat source can be directly used; when the demand changes, the opening of the second valve 21 and the fourth valve 22 can be adjusted to change the heat transfer rate. The setting of the second control component enables the system to use the medium-temperature heat source more efficiently, reducing the dependence on the high-temperature heat source or the low-temperature heat source.

[0033] The third control component includes a third plate exchanger 30 and two third water pumps 31; the third plate exchanger 30 is connected in series on the path from the low-temperature heat source pipeline 4 to the parallel well group 7; one third water pump 31 is connected to the return water path from the low-temperature heat source pipeline 4 to the third plate exchanger 30, and the other third water pump 31 is connected to the return water path from the parallel well group 7 to the heat pump 1.

[0034] In the above scheme, the third plate exchanger 30 is connected in series on the path from the low-temperature heat source pipeline 4 to the parallel well group 7, so that the heat in the low-temperature heat source pipeline 4 can be transferred to the medium in the parallel well group 7 through the plate exchanger, and because the parallel well group 7 is connected in parallel with the tertiary well group 5 and the secondary well group 6, the heat of the entire heating system is indirectly distributed. The third water pump 31 located between the low-temperature heat source pipeline 4 and the third plate exchanger 30 ensures that the low-temperature heat source can stably flow to the plate exchanger for heat exchange. The third water pump 31 located between the parallel well group 7 and the heat pump 1 ensures that the medium after heat exchange can smoothly flow back to the heat pump 1 for further heat enhancement or direct supply to users. When the low-temperature heat source is sufficient, the heat transfer rate can be increased by increasing the speed of the third water pump 31 located between the low-temperature heat source pipeline 4 and the third plate exchanger 30; when the demand is reduced, the speed of the third water pump 31 located between the parallel well group 7 and the heat pump 1 can be reduced or the running time of the heat pump 1 can be reduced to save energy.

[0035] The present application also includes a compensation unit; one working end of the compensation unit is connected in parallel to the path from the tertiary well group 5, the secondary well group 6, and the parallel well group 7 to the heat pump 1, and the other working end is connected to the external heat source environment, which can compensate for the energy supply status of the tertiary well group 5, the secondary well group 6, and the parallel well group 7 to the heat pump 1; wherein the compensation unit includes a fourth plate exchanger 40 and two fourth water pumps 41; the fourth plate exchanger 40 is arranged on the path from the external heat source environment to the tertiary well group 5, the secondary well group 6, and the parallel well group 7 to the heat pump 1; one fourth water pump 41 is connected to the return water path from the external heat source environment to the fourth plate exchanger 40, and another fourth water pump 41 is connected to the path from the fourth plate exchanger 40 to the tertiary well group 5, the secondary well group 6, and the parallel well group 7 to the heat pump 1.

[0036] In the above scheme, the fourth plate exchanger 40 is arranged on the path from the external heat source environment to the tertiary well group 5, the secondary well group 6, the parallel well group 7 and the heat pump 1, so that the heat of the external heat source can be transferred to the medium in the tertiary well group 5, the secondary well group 6 and the parallel well group 7 through the fourth plate exchanger 40, or directly transferred to the water supply system in front of the heat pump 1. It should be noted that the external heat source includes solar collectors, industrial waste heat, geothermal energy, etc. The fourth water pump 41 located between the external heat source environment and the fourth plate exchanger 40 ensures that the external heat source can stably flow to the plate exchanger for heat extraction, and the medium located between the fourth plate exchanger 40 and the water supply system in front of the heat pump 1 ensures that the medium after heat exchange can smoothly flow back to the heat pump 1 for further heat enhancement or direct supply to users.

[0037] The setting of the compensation unit in this application enables the system to be adjusted in real time according to the changes in the external heat source and user needs. When the energy supply status of the tertiary well group 5, the secondary well group 6 and the parallel well group 7 is insufficient, the compensation unit can be quickly started to extract heat from the external heat source for supplementation to ensure the continuous and stable operation of the system.

[0038] The first valve 11 , the third valve 12 , the second valve 21 and the fourth valve 22 are all three-way valves.

[0039] In the above scheme, the purpose of such a setting is to facilitate the control of fluid flow in three directions, allowing the fluid to be guided from one path to another, or allowing the fluid to flow in two paths at the same time, thereby adjusting the flow distribution of the high-temperature heat source pipeline 2, the medium-temperature heat source pipeline 3, and the low-temperature heat source pipeline 4 to the tertiary well group 5, the secondary well group 6, the parallel well group 7 and the heat pump 1, thereby enhancing the system's adjustment ability and adaptability.

[0040] Combination Figure 6-Figure 7 As shown, the present application includes a preheating well group, which includes a tertiary preheating well group 52, a secondary preheating well group 62, and a parallel preheating well group 72; the tertiary preheating well group 52 is connected in parallel to the return water path and the water supply path of the tertiary well group 5, and is used to preheat the return water of the tertiary well group 5; the secondary preheating well group 62 is connected in parallel to the return water path and the water supply path of the secondary well group 6, and is used to preheat the return water of the secondary well group 6; the parallel preheating well group 72 is connected in series to the return water path and the water supply path of the parallel well group 7, and is used to preheat the return water of the parallel well group 7.

[0041] In the above scheme, when the return water of the tertiary well group 5 returns from the user terminal or the heat exchange process, it first flows through the tertiary preheating well group 52. The heat source (underground heat energy, industrial waste heat, etc.) in the preheating well group exchanges heat with the return water to increase the temperature of the return water. The preheated return water then enters the water supply path of the tertiary well group 5, and is further heated by the heat exchanger again, or is directly used for heating. The return water of the secondary well group 6 also first flows through the secondary preheating well group 62 for preheating. The preheating process increases the temperature of the return water, making it more suitable for subsequent heating or heat supply processes. The preheated return water enters the water supply path of the secondary well group 6 and is further heated by the second heat exchanger. The return water of the parallel well group 7 is also first preheated by the parallel preheating well group 72 to reduce energy consumption in the subsequent heating process.

[0042] In the present application, the preheating well group improves the water temperature entering the water supply path of the tertiary well group 5, the secondary well group 6 and the parallel well group 7 by preheating the return water, which not only prevents premature thermal breakthrough of each well path in the tertiary well group 5, the secondary well group 6 and the parallel well group 7 due to too low return water temperature, but also effectively utilizes the heat source around the well group, thereby improving the thermal energy utilization efficiency of the entire heating system.

[0043] It is feasible that each well path of the tertiary preheating well group 52, the secondary preheating well group 62, and the parallel preheating well group 72 is arranged in any one of a determinant, multi-layer concentric circle or ring, and a cluster structure, and the well path diameters of the tertiary preheating well group 52, the secondary preheating well group 62, and the parallel preheating well group 72 are all larger than the well path diameters of the tertiary well group 5, the secondary well group 6, and the parallel well group 7.

[0044] In the above scheme, the staff can use different well structures to optimize the heat transfer path, reduce heat loss, and improve heat exchange efficiency. Preferably, the present application arranges the wells of the preheating well groups (three-stage preheating well group 52, two-stage preheating well group 62, parallel preheating well group 72) in a multi-layer concentric circle or ring manner.

[0045] It is feasible that the multiple well paths of the preheating well group are arranged in multiple layers of concentric circles and form a spiral structure. And each well path of the preheating well group is a double-layer structure, wherein the outer well of each well path of the preheating well group is connected to the water supply pipeline of the tertiary well group 5, the secondary well group 6 and the parallel well group 7; the inner well of each well path of the preheating well group is connected to the return pipeline of the tertiary well group 5, the secondary well group 6 and the parallel well group 7. And the water supply path and the return path of each well path of the preheating well group are in opposite directions.

[0046] Among them, the first outer well in the outermost layer of the preheating well group is connected to the outer wells in the outermost layer in sequence counterclockwise or clockwise along the center of the circle until the last outer well in the outermost layer, the last outer well in the outermost layer is connected to the first outer well in the inner layer, the first outer well in the inner layer is connected to the remaining outer wells in the inner layer in sequence along the outermost layer in the same direction (counterclockwise or clockwise) until the last outer well in the inner layer, the last outer well in the inner layer is connected to the outer well in the central layer, and the outer well in the central layer is connected to the third-level well group 5, the second-level well group 6 and the parallel well group 7; The first inner well in the outermost layer of the preheating well group is connected to the inner wells in the outermost layer in a counterclockwise or clockwise direction along the center of the circle until the last inner well in the outermost layer, the last inner well in the outermost layer is connected to the first inner well in the inner layer, the first inner well in the inner layer is connected to the remaining inner wells in the inner layer in the same direction (counterclockwise or clockwise) along the outermost layer until the last inner well in the inner layer, the last inner well in the inner layer is connected to the inner well in the central layer, and the inner well in the central layer is connected to the tertiary well group 5, the secondary well group 6 and the parallel well group 7.

[0047] The purpose of this arrangement is to enable the return water flowing through the preheating well group to fully contact the surrounding waste heat environment (underground heat, industrial waste heat), so as to reduce the large difference between the return water temperature of the tertiary well group 5, the secondary well group 6 and the parallel well group 7 and the supply water temperature during the return water, thereby avoiding the premature occurrence of thermal breakthrough in the tertiary well group 5, the secondary well group 6 and the parallel well group 7.

[0048] A control method for a multi-grade heat source heating system further includes the following steps: During heat storage, in the path of the high-temperature heat source pipeline 2, if the return water temperature is greater than or equal to 40°C, the first valve 11 is opened to allow hot water at this temperature to enter the water supply path of the low-temperature heat source pipeline 4; if the return water temperature is less than 40°C, the water is directly returned to the high-temperature heat source pipeline 2, and is again subjected to secondary heat exchange by the first plate exchanger 10 until the temperature reaches the range of 80°C-90°C, and then stored in the tertiary well group 5. When the return water temperature of the tertiary well group 5 reaches 55°C, heat storage is stopped; In the path of the medium-temperature heat source pipeline 3, if the return water temperature is less than 40°C, the second valve 21 is opened to allow hot water of this temperature to enter the water supply path of the medium-temperature heat source pipeline 3, and the hot water is subjected to secondary heat exchange through the second plate exchanger 20 until the hot water reaches a temperature range of greater than or equal to 57°C and less than 87°C and is stored in the secondary well group 6. When the return water temperature of the secondary well group 6 reaches 42°C, the heat storage is stopped; In the path of the low-temperature heat source pipeline 4, if the return water temperature is less than 30°C, the second valve 21 is opened to allow hot water at this temperature to enter the water supply path of the low-temperature heat source pipeline 4, and undergo secondary heat exchange through the third plate exchanger 30 until the hot water reaches a temperature range of greater than 40°C and less than 57°C and is stored in the parallel well group 7. When the return water temperature of the parallel well group 7 reaches 32°C, the heat storage is stopped; When releasing heat, the third valve 12 is opened, and the high-temperature water of the tertiary well group 5 with a temperature greater than or equal to 48°C enters the fourth plate exchanger 40, and the fourth plate exchanger 40 converts the high-temperature water with a temperature of 45°C into hot water for the second time, and supplies water to the user terminal. When the high-temperature water of the tertiary well group 5 is less than 48°C, the water of this temperature is output to the heat pump 1 via the first water pump 13, and 55°C hot water is provided to the user terminal. Open the fourth valve 22, and the water with a temperature greater than or equal to 48°C in the secondary well group 6 is output to the fourth plate exchanger 40 via the second water pump 23, and the hot water with a temperature less than 48°C enters the heat pump 1, and the hot water in the parallel well group 7 enters the heat pump 1 via the third water pump 31.

[0049] In the above scheme, the control method provided by the present application realizes the hierarchical storage and utilization of heat by accurately controlling the heat sources of different temperature ranges to enter the corresponding storage well groups. According to the different water temperatures of the well groups, direct heating or heating after the temperature is increased by the heat pump 1 is flexibly selected to ensure the stable heating demand of the user terminal.

[0050] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other. Each embodiment focuses on the differences from other embodiments.

[0051] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit the present application. Although the present application has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present application.

Claims

1. A multi-grade heat source heating system, characterized in that: It comprises a heat pump (1), a high-temperature heat source pipeline (2), a medium-temperature heat source pipeline (3), a low-temperature heat source pipeline (4), a third-level well group (5), a second-level well group (6), a parallel well group (7), a first control component, a second control component and a third control component; One working end of the heat pump (1) is connected to an external user terminal, and the other working end thereof is respectively connected to a working end of the tertiary well group (5), a working end of the secondary well group (6), and a working end of the parallel well group (7); The other working end of the three-level well group (5) is connected to a working end of the high-temperature heat source pipeline (2); The other working end of the secondary well group (6) is connected to a working end of the medium-temperature heat source pipeline (3); The other working end of the parallel well group (7) is connected to a working end of the low-temperature heat source pipeline (4); Each well path of the parallel well group (7) is connected in parallel with each well path of the third-level well group (5) and each well path of the second-level well group (6); The other working end of the high-temperature heat source pipeline (2) is connected to an external high-temperature environment pipe; The other working end of the medium-temperature heat source pipeline (3) is connected to an external medium-temperature environment pipe; The other working end of the low-temperature heat source pipeline (4) is connected to an external low-temperature environment pipe; The first control component is arranged on a path from the high-temperature heat source pipeline (2) through the three-level well group (5) to the heat pump (1), and is capable of switching the energy supply state of the high-temperature heat source pipeline (2) and the heat pump (1) to the three-level well group (5); The second control component is arranged on a path from the medium-temperature heat source pipeline (3) through the secondary well group (6) to the heat pump (1), and is capable of switching the energy supply state of the medium-temperature heat source pipeline (3) and the heat pump (1) to the tertiary well group (5); The third control component is arranged on a path from the low-temperature heat source pipeline (4) through the parallel well group (7) to the heat pump machine (1), and is capable of switching the energy supply state of the low-temperature heat source pipeline (4) and the heat pump machine (1) to the parallel well group (7).

2. The multi-grade heat source heating system according to claim 1, characterized in that: The first control component comprises a first plate exchanger (10), a first valve (11), a third valve (12) and two first water pumps (13); The first plate exchanger (10) is connected in series on a path from the high-temperature heat source pipeline (2) to the third-level well group (5); The first valve (11) is connected to a water return path of the high-temperature heat source pipeline (2) leading to the first plate exchanger (10); The third valve (12) is connected to the water supply path from the third-level well group (5) to the heat pump (1); One of the first water pumps (13) is connected to a return water path from the first valve (11) to the first plate exchanger (10), and another of the first water pumps (13) is connected to a return water path from the three-level well group (5) to the heat pump (1).

3. The multi-grade heat source heating system according to claim 2, characterized in that: The second control component comprises a second plate exchanger (20), a second valve (21), a fourth valve (22), and two second water pumps (23); The second plate exchanger (20) is connected in series on the path from the medium-temperature heat source pipeline (3) to the secondary well group (6); The second valve (21) is connected to the return water path of the medium-temperature heat source pipeline (3) leading to the second plate exchanger (20); The fourth valve (22) is connected to the water supply path from the secondary well group (6) to the heat pump (1); One of the second water pumps (23) is connected to a return water path from the medium-temperature heat source pipeline (3) to the second plate exchanger (20), and another of the second water pumps (23) is connected to a return water path from the secondary well group (6) to the heat pump (1).

4. The multi-grade heat source heating system according to claim 3, characterized in that: The third control component comprises a third plate converter (30) and two third water pumps (31); The third plate exchanger (30) is connected in series on the path of the low-temperature heat source pipeline (4) leading to the parallel well group (7); One of the third water pumps (31) is connected to a return water path from the low-temperature heat source pipeline (4) to the third plate exchanger (30), and another of the third water pumps (31) is connected to a return water path from the parallel well group (7) to the heat pump (1).

5. The multi-grade heat source heating system according to claim 4, characterized in that: Also includes a compensation unit; One working end of the compensation unit is connected in parallel to the path from the tertiary well group (5), the secondary well group (6), and the parallel well group (7) to the heat pump (1), and the other working end is connected to an external heat source environment, so as to compensate for the energy supply status of the tertiary well group (5), the secondary well group (6), and the parallel well group (7) to the heat pump (1); The compensation unit comprises a fourth plate converter (40) and two fourth water pumps (41); The fourth plate exchanger (40) is arranged on a path from the external heat source environment to the third-level well group (5), the second-level well group (6), the parallel well group (7) and the heat pump (1); One of the fourth water pumps (41) is connected to a return water path from the external heat source environment to the fourth plate exchanger (40), and another of the fourth water pumps (41) is connected to a path from the fourth plate exchanger (40) to the tertiary well group (5), the secondary well group (6), the parallel well group (7) to the heat pump (1).

6. The multi-grade heat source heating system according to claim 3, characterized in that: The first valve (11), the third valve (12), the second valve (21) and the fourth valve (22) are all three-way valves.

7. A control method for a multi-grade heat source heating system, characterized in that: The multi-grade heat source heating system according to claim 5 further comprises the following steps: During heat storage, if the return water temperature in the high-temperature heat source pipeline (2) is greater than or equal to 40°C, the first valve (11) is opened to allow hot water at this temperature to enter the water supply path of the low-temperature heat source pipeline (4); if the return water temperature is less than 40°C, the water is directly returned to the high-temperature heat source pipeline (2), and is again subjected to secondary heat exchange in the first plate exchanger (10) until the temperature reaches a range of 80°C-90°C, and is then stored in the tertiary well group (5). When the return water temperature of the tertiary well group (5) reaches 55°C, heat storage is stopped; In the path of the medium-temperature heat source pipeline (3), if the return water temperature is less than 40°C, the second valve (21) is opened to allow hot water at this temperature to enter the water supply path of the medium-temperature heat source pipeline (3), and to undergo secondary heat exchange through the second plate exchanger (20) until the hot water reaches a temperature range of greater than or equal to 57°C and less than 87°C and is stored in the secondary well group (6). When the return water temperature of the secondary well group (6) reaches 42°C, heat storage is stopped; In the path of the low-temperature heat source pipeline (4), if the return water temperature is less than 30°C, the second valve (21) is opened to allow hot water at this temperature to enter the water supply path of the low-temperature heat source pipeline (4), and to undergo secondary heat exchange through the third plate exchanger (30) until the hot water reaches a temperature range of greater than 40°C and less than 57°C and is stored in the parallel well group (7). When the return water temperature of the parallel well group (7) reaches 32°C, heat storage is stopped; When releasing heat, the third valve (12) is opened, and the high-temperature water of 48° C. or higher from the three-level well group (5) enters the fourth plate heat exchanger (40), and the fourth plate heat exchanger (40) performs secondary conversion to hot water with a temperature of 45° C. and supplies water to the user terminal. When the high-temperature water of the three-level well group (5) is less than 48° C., the water of this temperature is output to the heat pump (1) via the first water pump (13), and hot water of 55° C. is provided to the user terminal. The fourth valve (22) is opened, and water with a temperature of 48°C or higher in the secondary well group (6) is output to the fourth plate exchanger (40) via the second water pump (23), and hot water with a temperature of less than 48°C enters the heat pump (1), and hot water in the parallel well group (7) enters the heat pump (1) via the third water pump (31).

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