Large-temperature-difference flexible heat supply method and system based on low-grade heat source and water loop heat pump

Abstract

According to the large-temperature-difference flexible heat supply method and system based on the low-grade heat source and the water loop heat pump, the low-grade combined clean heat source is composed of process waste heat, solar energy and geothermal energy and meets the heat supply requirements of heat users such as a conventional heat supply tail end and the water loop heat pump, a heat supply network conducts heat supply transmission and distribution according to the cascade efficient principle, the water supply temperature of the heat supply network is 40-50 DEG C, and the return water temperature is 4-7 DEG C; the ultra-large temperature difference heat supply network running and zero-carbon heat supply mode driven by a low-grade heat source is achieved, heat supply network supplied water of about 45 DEG C is firstly fed into a mixed tail end heat user, is cooled to 35-38 DEG C and then is fed into a floor heating heat user, is cooled to 30-33 DEG C and then is fed into a mixed tail end water loop heat pump user, and is cooled to 10-12 DEG C and then enters a floor heating water loop heat pump user. One part of the heat supply network return water cooled to 4-7 DEG C is returned to the ground source heat exchanger to be circularly heated, and the other part of the heat supply network return water is returned to the factory heat radiator to be heated to 35-40 DEG C, and is supplied out through the low-temperature large-temperature-difference energy storage tank after being subjected to heat compensation by solar energy.

Description

Technical Field

[0001] This patent relates to a large-temperature-difference flexible heating method and system based on low-grade heat sources and water-loop heat pumps, belonging to the technical field of dual-carbon clean heating. Background Art

[0002] The future energy revolution in China will inevitably require a greater reduction in energy consumption, especially the consumption of fossil energy. Under this background, the heating field also necessarily calls for revolutionary technological innovations and engineering implementation forms. Making full use of various waste heat resources of high-energy-consuming industrial enterprises, as well as natural energy such as solar energy and geothermal energy, has become one of the main alternative forms for significantly reducing fossil energy heating.

[0003] In actual engineering practice, each of the above-mentioned low-grade clean energy sources has its own limitations when used for heating. Among them, although industrial waste heat resources are very rich, their energy grades are often relatively low. Most process waste heat is wasted through the cooling circulating water system, and its outlet water temperature is often between 30 and 40 °C, usually unable to directly supply heat, but requires recovery through absorption heat pumps, compression heat pumps, etc., which requires a large amount of high-quality and high-cost energy such as driving steam or electric energy.

[0004] Due to the relatively low energy density of solar energy and the relatively low actual system conversion efficiency during winter heating operation, especially it can only be collected and used when there is sunlight during the day, so there are few cases mainly relying on solar energy for heating, and it can only be used as an auxiliary heat source.

[0005] The energy grade of shallow geothermal energy is too low (5 - 15 °C), and it must rely on heat pumps for recovery to be used for heating.

[0006] Currently, the supply water temperature of most primary heat networks is often relatively high (60 - 120 °C), and the return water temperature is mostly between 40 and 55 °C. This is the basic operating condition of traditional heating heat sources such as cogeneration heat sources or boiler houses and their heat network systems.

[0007] On the other hand, on the heating user side, due to limitations of the end types, public buildings or old residential buildings using radiators, fan coil units, etc. require a relatively high supply water temperature, such as 45 - 60 °C, and the return water temperature is often 35 - 45 °C. Currently, a larger proportion of the heating end types in newly built residential buildings are floor heating, and the supply water temperature only needs 35 - 40 °C, and the return water temperature is 25 - 35 °C.

[0008] Another special type of indoor heating equipment system is the water-loop heat pump system. That is, if there is a cheap low-temperature heat source (such as in the range of 8 - 15 °C) sent to each indoor heat user, and a small household water-loop heat pump unit is installed in each household. Its evaporator absorbs heat from the low-temperature heat source water, and through the heat pump cycle, the heat is transferred to the indoor heating water by the heat pump condenser to achieve efficient heat pump heating. Usually, for an energy-efficient building with a heating load of about 3 - 4 MW for 100 square meters, only an input power of about 1 kW (equivalent to the power consumption of a 1.5-horsepower household air conditioner) is required to meet the heating demand. However, this heating method is rarely used in China, lacking actual application scenarios and cases, with relatively high investment, lacking economic viability and operability in actual heating operation, and having poor replicability. Summary of the Invention

[0009] The purpose and task of this patent are to design a brand-new low-temperature large-temperature-difference heat supply system based on low-grade heat sources and water-loop heat pump technology, to achieve large-scale urban central heating by making the most of process waste heat and natural energy, and it is expected to contribute to the realization of the carbon neutrality goal in the heating field.

[0010] The specific description of this patent is: a large temperature difference flexible heating system based on low-grade heat sources and water ring heat pumps, which includes a low-grade combined clean heat source subsystem, a low-temperature large temperature difference heating end user group, and a low-temperature large temperature difference heat network water transmission and distribution subsystem. It is characterized in that the low-grade combined clean heat source subsystem includes heat exchange equipment and energy storage equipment for factory process waste heat, solar energy, and geothermal energy; the low-temperature large temperature difference heating end user group includes a mixed end user 6, a floor heating user 7, a mixed end water ring heat pump user U1, and a floor heating water ring heat pump user U2; the low-temperature large temperature difference heat network water transmission and distribution subsystem includes a double-line main pipe for heat network supply and return water, and a series-parallel cascade transmission and distribution pipeline system that combines zoning in series but with users in the same area in parallel. Among them, the factory process waste heat is used as the main heat source, and a factory radiator 1 for discharging process waste heat is provided. The cooling water inlet of the factory radiator 1 is connected to the water outlet of the process cooling pump P1, and the water inlet of the process cooling pump P1 is respectively connected to the water outlet of the V2 electric valve and the water outlet of the V3 electric valve. The water inlet of the V2 electric valve is connected to the outlet of the cooling tower 4. In addition to being connected to the water inlet of the cooling tower 4 through the V1 electric valve, the cooling water outlet of the factory radiator 1 is also connected to the water inlet of the solar collector 2 through the V5 electric valve. The water outlet of the solar collector 2 is connected to the water inlet of the V6 electric valve, and the cooling water outlet of the factory radiator 1 is also connected to the water outlet of the V6 electric valve through the V4 electric valve. The pipeline of the mixed water is respectively connected to the water inlet of the V8 electric valve and the water inlet of the low-temperature large temperature difference energy storage tank 5 through the V7 electric valve. The water outlet of the low-temperature large temperature difference energy storage tank 5 is connected to the water inlet of the energy storage booster pump P2. The water outlet of the energy storage booster pump P2 is respectively connected to the water inlet of the V10 electric valve and the water outlet of the V8 electric valve through the V9 electric valve. The water outlet of the V8 electric valve is also connected to the heating water inlet of the mixed end user 6. The heating water outlet of the mixed end user 6 is respectively connected to the water outlet of the V10 electric valve, the water inlet of the V11 electric valve, and the water inlet of the V12 electric valve.The water outlet of the V12 electric valve is connected to the heating water inlet of the floor heating heat user 7. The heating water outlet of the floor heating heat user 7 is connected to the water outlet of the V11 electric valve, the water inlet of the V14 electric valve, and the water inlet of the V15 electric valve through the V13 electric valve. The water outlet of the V15 electric valve is respectively connected to the water inlet of the V16 electric valve and the water inlet of the V17 electric valve of the hybrid terminal water loop heat pump user U1. The hybrid terminal water loop heat pump user U1 is also provided with a high-temperature heat source type water loop heat pump 8, a first user heating pump 85, a hybrid terminal heat exchanger 86, and a V18 electric valve. The high-temperature heat source type water loop heat pump 8 includes a high-temperature evaporator 81, a high-temperature compressor 82, a high-temperature condenser 83, a high-temperature expansion valve 84, and its connecting pipeline components. The water inlet of the high-temperature evaporator 81 is connected to the water outlet of the V17 electric valve, and the water outlet of the high-temperature evaporator 81 is connected to the water inlet of the V18 electric valve. The water outlet of the high-temperature condenser 83 is connected to the heating water inlet of the hybrid terminal heat exchanger 86 through the first user heating pump 85, and the water inlet of the high-temperature condenser 83 is connected to the heating water outlet of the hybrid terminal heat exchanger 86. The water outlet of the V18 electric valve is respectively connected to the water outlet of the V16 electric valve, the water outlet of the V23 electric valve, the water inlet of the V19 electric valve, and the water inlet of the V20 electric valve of the floor heating water loop heat pump user U2. The floor heating water loop heat pump user U2 is also provided with a low-temperature heat source type water loop heat pump 9, a second user heating pump 95, a floor heating heat exchanger 96, and a V21 electric valve. The low-temperature heat source type water loop heat pump 9 includes a low-temperature evaporator 91, a low-temperature compressor 92, a low-temperature condenser 93, a low-temperature expansion valve 94, and its connecting pipeline components. The water inlet of the low-temperature evaporator 91 is connected to the water outlet of the V20 electric valve, and the water outlet of the low-temperature evaporator 91 is connected to the water inlet of the V21 electric valve. The water outlet of the low-temperature condenser 93 is connected to the heating water inlet of the floor heating heat exchanger 96 through the second user heating pump 95, and the water inlet of the low-temperature condenser 93 is connected to the heating water outlet of the floor heating heat exchanger 96. The water outlet of the V21 electric valve is respectively connected to the water outlet of the V19 electric valve, the water inlet of the V22 electric valve, the water inlet of the V3 electric valve, and the water outlet of the V14 electric valve. The water outlet of the V22 electric valve is connected to the water inlet of the ground source heat exchanger 3. The water outlet of the ground source heat exchanger 3 is respectively connected to the water inlet of the V23 electric valve and the water inlet of the V24 electric valve through the ground source circulation pump P3. The water outlet of the V24 electric valve is connected to the water outlet of the factory radiator 1.;

[0011] The hybrid terminal heat users 6 include several groups of heat users in the form of radiator, fan coil or floor heating heat supply terminals. The connection relationship of the heating water branch between each heat user is parallel, that is, the groups of heat users of the hybrid terminal heat users 6 share a heating water supply main pipe and a return water main pipe; the floor heating heat users 7 include several groups of heat users in the form of floor heating heat supply terminals. The connection relationship of the heating water branch between each heat user is parallel, that is, the groups of heat users of the floor heating heat users 7 share a heating water supply main pipe and a return water main pipe; the hybrid terminal water loop heat pump users U1 include several groups of heat users in the form of radiator, fan coil or floor heating heat supply terminals. Each heat user is equipped with an independent high-temperature heat source type water loop heat pump heating system, and the connection relationship of the low-temperature surplus heat water branch between each heat user is parallel, that is, the groups of heat users of the hybrid terminal water loop heat pump users U1 share a low-temperature surplus heat water supply main pipe and a return water main pipe; the floor heating water loop heat pump users U2 include several groups of heat users in the form of floor heating heat supply terminals. Each heat user is equipped with an independent low-temperature heat source type water loop heat pump heating system, and the connection relationship of the low-temperature surplus heat water branch between each heat user is parallel, that is, the groups of heat users of the floor heating water loop heat pump users U2 share a low-temperature surplus heat water supply main pipe and a return water main pipe.

[0012] The pipe end of a shared heating water supply main pipe of the groups of heat users of the hybrid terminal heat users 6 is truncated, and the total outlet of a shared heating water return main pipe is connected to the total inlet of a shared heating water supply main pipe of the groups of heat users of the floor heating heat users 7. That is, the heating network water of the hybrid terminal heat users 6 and the floor heating heat users 7 forms a series relationship as a whole; the pipe end of a shared heating water supply main pipe of the groups of heat users of the floor heating heat users 7 is truncated, and the total outlet of a shared heating water return main pipe is connected to the total inlet of a shared low-temperature surplus heat water supply main pipe of the groups of heat users of the hybrid terminal water loop heat pump users U1. That is, the heating network water of the floor heating heat users 7 and the low-temperature heat source water of the hybrid terminal water loop heat pump users U1 form a series relationship as a whole; the pipe end of a shared low-temperature heat source water supply main pipe of the groups of heat users of the hybrid terminal water loop heat pump users U1 is truncated, and the total outlet of a shared low-temperature heat source water return main pipe is connected to the total inlet of a shared low-temperature surplus heat water supply main pipe of the groups of heat users of the floor heating water loop heat pump users U2. That is, the low-temperature heat source water of the hybrid terminal water loop heat pump users U1 and the low-temperature heat source water of the floor heating water loop heat pump users U2 form a series relationship as a whole.

[0013] The ground source heat exchanger 3 includes several distributed shallow geothermal energy heat exchangers, which adopt the form of buried pipe heat exchanger, groundwater well group form or large flow surface water and seawater form; the low-temperature heat source water inlet pipe and outlet pipe are respectively communicated with the low-temperature heat source water outlet pipe and inlet pipe of the floor heating water ring heat pump user U2 during the heating period, and are communicated with the cooling circulating water outlet pipe and inlet pipe of the factory radiator 1 during the non-heating period.

[0014] The factory radiator 1 includes one or several heat exchangers for process heat dissipation in high-energy-consuming factories, and these heat exchangers for process heat dissipation can be located in one or several factories.

[0015] The solar collector 2 includes one or several groups of solar collectors. When several groups are set, their geographical locations can be arranged in a centralized manner or a decentralized manner.

[0016] The temperature of the supply main pipe of the low-temperature large temperature difference heat network water transmission and distribution subsystem is 40 - 50 °C, and the temperature of the return main pipe is 4 - 7 °C. Among them, the temperature of the heating water supply branch main pipe of the mixed end heat user 6 is 40 - 50 °C, the temperature of the heating water supply branch main pipe of the floor heating heat user 7 is 35 - 38 °C, the temperature of the low-temperature heat source water supply branch main pipe of the mixed end water ring heat pump user U1 is 30 - 33 °C, the temperature of the low-temperature heat source water supply branch main pipe of the floor heating water ring heat pump user U2 is 10 - 12 °C, and the temperature of the low-temperature heat source water return branch main pipe of the floor heating water ring heat pump user U2 is 4 - 7 °C; the temperature of the low-temperature heat source water outlet pipe of the ground source heat exchanger 3 is 7 - 15 °C, the temperature of the cooling water outlet of the factory radiator 1 is 35 - 40 °C, and the temperature of the water outlet of the solar collector 2 is 40 - 50 °C.

[0017] The large temperature difference flexible heating system based on low-grade heat sources and water ring heat pumps is characterized in that the specific working method of the large temperature difference flexible heating system is as follows.

[0018] (1) The working method on the heat source supply side during the heating period is as follows.

[0019] I. The heat network water heating method and process of the factory radiator 1 are as follows: The V1 electric valve and the V2 electric valve are closed or closed slightly, V24 is closed, V3 is opened, the low-temperature heat source water return from the floor heating water ring heat pump user U2 is sent to the water inlet of the process cooling pump P1 through the V21 electric valve, and after being pressurized by the process cooling pump P1, it is sent to the factory radiator 1 and heated to 35 - 40 °C.

[0020] II. The heat network water heating method and process of the solar collector 2 are as follows: The V4 electric valve is in an adjustment state, the V5 electric valve and the V6 electric valve are opened during the day when there is sunlight and closed when there is no sunlight, the V8 electric valve is in an adjustment state, the heat network water outlet from the factory radiator 1 enters the solar collector 2 through the V5 electric valve for reheating, and the water temperature is increased to 40 - 50 °C.

[0021] III. The heat network water heat storage method and process of the low-temperature large temperature difference heat storage tank 5 are as follows: The V7 electric valve is opened when heat storage is required, otherwise it is closed. When the low-temperature large temperature difference heat storage tank 5 needs to supply heat, the energy storage booster pump P2 is started, otherwise it is closed.

[0022] IV. The low-temperature heat source water heating method and process of the ground source heat exchanger 3 are as follows: The ground source heat exchanger 3 serves as a peak-shaving heat source heater and is only used to heat the outlet water of the low-temperature heat source water for the floor heating water ring heat pump user U2. When heating of the low-temperature heat source water is required, the V22 electric valve is opened, the V23 electric valve is opened, the ground source circulation pump P3 is started, and the outlet water of the ground source heat exchanger 3 is sent by the ground source circulation pump P3 to the low-temperature evaporator 91 of the low-temperature heat source type water ring heat pump 9. After releasing heat, it returns to the water inlet of the ground source heat exchanger 3.

[0023] (2) The working method on the heating user side during the heating period is as follows.

[0024] I. The heat supply method and process of the hybrid terminal heat user 6 are as follows: The heat network water supply from the V8 electric valve and the V9 electric valve is sent into the heating water supply branch pipe of the hybrid terminal heat user 6 for heating, and then sent to the downstream floor heating heat user 7. Among them, the heating water flow rate and heat supply amount of the hybrid terminal heat user 6, as well as the heat network water flow rate and heat supply amount from the low-temperature large temperature difference heat storage tank 5, are adjusted by the opening degrees of the V9 electric valve and the V10 electric valve.

[0025] II. The heat supply method and process of the floor heating heat user 7 are as follows: The heat network water from the heating water return branch pipe of the hybrid terminal heat user 6 and the bypass heat network water from the V9 electric valve and the V10 electric valve are mixed and then sent into the heating water supply branch pipe of the floor heating heat user 7 for heating, and then sent to the downstream hybrid terminal water ring heat pump user U1. Among them, the heating water flow rate and heat supply amount of the floor heating heat user 7 are adjusted by the opening degrees of the V11 electric valve, the V12 electric valve, and the V13 electric valve.

[0026] III. The heat supply method and process of the hybrid terminal water ring heat pump user U1 are as follows: The V15 electric valve is opened, and the heat network water from the heating water return branch pipe of the floor heating heat user 7 is sent into the low-temperature heat source water supply branch pipe of the hybrid terminal water ring heat pump user U1, and is absorbed and cooled by the high-temperature evaporator 81 of the high-temperature heat source type water ring heat pump 8, and then sent to the downstream floor heating water ring heat pump user U2. Among them, the low-temperature heat source water flow rate and heat exchange amount of the high-temperature evaporator 81 are adjusted by the opening degrees of the V16 electric valve, the V17 electric valve, and the V18 electric valve. The heating water outlet of the high-temperature condenser 83 of the high-temperature heat source type water ring heat pump 8 is sent to the hybrid terminal heat exchanger 86 for heating by the first user heating pump 85, and after cooling, it returns to the heating water inlet of the high-temperature condenser 83 to continue circulating and heating.

[0027] IV. The heating method and process for the floor heating water ring heat pump user U2 are as follows: The low-temperature surplus hot water in the return branch main pipe of the low-temperature heat source water of the hybrid end water ring heat pump user U1 is mixed with the low-temperature heat source water outlet from the ground source heat exchanger 3, and then sent into the supply branch main pipe of the low-temperature heat source water of the floor heating water ring heat pump user U2. It is absorbed by the low-temperature evaporator 91 of the low-temperature heat source type water ring heat pump 9 for heat absorption and temperature reduction, and then returns to the heat source to enter the system. Among them, the flow rate and heat exchange amount of the low-temperature heat source water of the low-temperature evaporator 91 are adjusted by the opening degrees of the V19 electric valve, V20 electric valve, and V21 electric valve. The heating water outlet of the low-temperature condenser 93 of the high-temperature heat source type water ring heat pump 8 is sent to the floor heating heat exchanger 96 for heating by the second user heating pump 95, and after temperature reduction, it returns to the heating water inlet of the low-temperature condenser 93 to continue circulating and heating.

[0028] V. The heat supply regulation and circulating water flow matching method among the heat supply end heat user groups: The heat supply amount and heat network water flow of the hybrid end heat user 6 are adjusted by the opening degrees of the V9 electric valve and V10 electric valve. The heat supply amount and heat network water flow of the floor heating heat user 7 are adjusted by the opening degree of the V11 electric valve. The heat supply amount and low-temperature heat source water flow of the hybrid end water ring heat pump user U1 are adjusted by the opening degree of the V16 electric valve. The heat supply amount and low-temperature heat source water flow of the floor heating water ring heat pump user U2 are adjusted by the opening degree of the V19 electric valve and the flow rate of the ground source circulation pump P3. When the heating load demand and the required low-temperature heat source water flow of the hybrid end water ring heat pump user U1 and the floor heating water ring heat pump user U2 decrease, the V14 electric valve is opened and adjusted by its opening degree.

[0029] (III) The working method during the non-heating period is as follows.

[0030] I. The circulating cooling working method of the factory radiator 1: Open the process cooling pump P1, V1 electric valve, and V2 electric valve, and cool the cooling water outlet of the factory radiator 1 through the cooling tower 4 and return it to the cooling water inlet of the factory radiator 1.

[0031] II. One of the working methods for the soil temperature recovery of the ground source heat exchanger 3: Preferably adopt the method of cooling the hybrid end water ring heat pump user U1 and the floor heating water ring heat pump user U2. When cooling is required in summer, close the V3 electric valve and V24 electric valve, open the V22 electric valve and V23 electric valve. The low-temperature heat source water outlet of the ground source heat exchanger 3 is sent by the ground source circulation pump P3 to the condensers of the water ring heat pumps of the hybrid end water ring heat pump user U1 and the floor heating water ring heat pump user U2 or directly sent into the terminal heat exchanger to cool the indoor air on the premise that no unexpected condensate water is generated at the terminal heat exchanger, and the waste heat circulating water returns to the ground source heat exchanger 3 after temperature increase to heat the underground soil, and the cooled low-temperature heat source water continues to circulate and heat.

[0032] II. The second method for the soil temperature recovery of the ground source heat exchanger 3: Secondly, adopt the method of heating with the waste heat of the factory radiator 1; Open the V22 electric valve and the V24 electric valve, close the V23 electric valve, and a part of the cooling water from the outlet of the factory radiator 1 is sent into the ground source heat exchanger 3 to heat the underground soil, and the cooled cooling water returns to the process cooling pump P1 and continues to circulate for heating.

[0033] (IV) Adopt a dedicated intelligent heat network control system to monitor the operating parameters of the large temperature difference flexible heating system based on low-grade heat sources and water-loop heat pumps, and perform annual real-time automatic control and regulation on the above heat storage and heat extraction processes.

[0034] (V) The behavior energy-saving heating method driven by economic benefits: Adopt a large temperature difference flexible heating system based on low-grade heat sources and water-loop heat pumps. The heating company undertakes the construction of the low-grade combined clean heat source subsystem, the low-temperature large temperature difference heat network water transmission and distribution subsystem, and the water-loop heat pump body. Its construction cost is usually basically equivalent to or slightly exceeds the statutory heat source / heat network / courtyard pipe network matching fee. The excess investment can be recovered through heating service charges. The heating company only needs to bear the power consumption cost of the low-temperature heat source water circulation pump of the water-loop heat pump, and the power consumption cost of the indoor water-loop heat pump host and the heating system is borne by the final heat user. Through independent control, the heat user can carry out room-by-room heating, time-of-use heating, greatly reduce the heating energy consumption and its power consumption, greatly reduce the low-temperature heat source water heat load and the heat source heat extraction demand in the entire heating area, and greatly reduce the energy consumption of the central heating system as a whole.

[0035] The innovation and technical effects of this patent are as follows.

[0036] This patent can realize that the central heating load is completely borne by industrial waste heat and zero-carbon low-grade energy resources such as solar energy and geothermal energy, and can perform cascade heating, cascade transmission and distribution, and cascade heat release for heating according to the energy resource endowment and the energy grade demand status on the heat user side, without consuming a large amount of fossil energy for heating, and truly realizes a large-scale carbon-neutral clean heating method.

[0037] On the heat user side, different heating terminal types are adopted, including conventional mixed terminal types and floor heating. More importantly, by adopting high- and low-temperature two-stage water ring heat pumps, the heat of the heat network circulating water is utilized in stages and deeply, and the return water temperature is finally reduced to an ultra-low temperature level of 4-7°C, thus realizing large temperature difference heating of low-temperature heat networks for the first time in the central heating industry. If the maximum heat network supply water temperature is calculated at 50°C, the maximum heat network supply-return water temperature difference can reach about 46°C, which is exactly equivalent to the supply-return water temperature difference level of traditional mainstream high-temperature large heat networks. For example, when the designed supply-return water temperature is 120 / 70°C and the temperature difference is 50°C, in actual operation, most of the supply water temperatures are 90-110°C and the return water temperatures are 40-55°C, and the actual supply-return water temperature difference is about 35-50°C. The supply-return water temperature difference of many medium and small-sized county-level heat networks is even only about 15-25°C; while for a few low-temperature water large-flow heating systems, the supply water temperature is even as low as 50-60°C and the return water is about 38-42°C, and the temperature difference is only about 15°C. Therefore, in the case where the supply water temperature of this patent is only 40-50°C and the supply-return water temperature difference reaches about 36-46°C, it belongs to a unique and original technology, which creates the best technical conditions for large-scale adoption of low-grade heat sources such as process waste heat as the main heat source for urban central heating, and can greatly reduce the circulating water flow, pump consumption and operation costs.

[0038] The water ring heat pumps adopt high-temperature heat source type and low-temperature heat source type respectively. The former is preferentially used for high-energy-consuming buildings and heating terminal types that require relatively high supply water temperatures, such as radiators and fan coil units, while the latter is mainly used for floor heating that requires relatively low supply water temperatures. Therefore, the temperature matching on the evaporator side and condenser side of the two pumps is better, the heating efficiency of the heat pump is greatly improved, the capacity of the heat pump and compressor is significantly lower, and the power consumption and operation costs are very low.

[0039] The return water temperature of the heat network returning to the factory is extremely low, which can greatly improve the cooling conditions of process production equipment, enhance production efficiency, improve the energy utilization rate of the whole factory, and achieve significant energy-saving and carbon-reduction benefits.

[0040] The heat network transmission and distribution system combines series and parallel connections to achieve the best matching between the heat source supply side and the demand side, flexibly adjust the heat supply of each heat user and the best heat extraction order on the heat source side, achieve better flexibility adjustment of the thermal system, realize flexible heating of the whole system, and further improve the system energy efficiency ratio and economy.

[0041] Therefore, this patent fundamentally changes the form and energy consumption of traditional heating systems that rely on fossil fuel heating and conventional heat pump heating, realizes high-efficiency central heating of large temperature difference heat networks with low-grade heat sources, has obvious energy-saving, healthy, environmental protection and economic advantages, is convenient for large-scale popularization and application, and reflects the actual development needs and the era theme of energy conservation and environmental protection under the condition of carbon neutrality. Description of the Drawings

[0042] Figure 1 It is a schematic diagram of the system of this patent.

[0043] Figure 1 The component numbers and names in it are as follows: factory radiator 1, solar collector 2, ground source heat exchanger 3, cooling tower 4, low-temperature large-temperature-difference energy storage tank 5, hybrid terminal heat user 6, floor heating heat user 7, high-temperature heat source type water loop heat pump 8, high-temperature evaporator 81, high-temperature compressor 82, high-temperature condenser 83, high-temperature expansion valve 84, first user heating pump 85, hybrid terminal heat exchanger 86, low-temperature heat source type water loop heat pump 9, low-temperature evaporator 91, low-temperature compressor 92, low-temperature condenser 93, low-temperature expansion valve 94, second user heating pump 95, floor heating heat exchanger 96, process cooling pump P1, energy storage booster pump P2, ground source circulation pump P3, hybrid terminal water loop heat pump user U1, floor heating water loop heat pump user U2. Specific implementation manners

[0044] Figure 1 It is a schematic diagram of the system of this patent.

[0045] The specific description of this patent is: a large-temperature-difference flexible heating system based on low-grade heat sources and water-loop heat pumps, which includes a low-grade combined clean heat source subsystem, a low-temperature large-temperature-difference heating end user group, and a low-temperature large-temperature-difference heat network water transmission and distribution subsystem. It is characterized in that the low-grade combined clean heat source subsystem includes heat exchange equipment and energy storage equipment for factory process waste heat, solar energy, and geothermal energy; the low-temperature large-temperature-difference heating end user group includes a hybrid end user 6, a floor heating user 7, a hybrid end water-loop heat pump user U1, and a floor heating water-loop heat pump user U2; the low-temperature large-temperature-difference heat network water transmission and distribution subsystem includes a double-line main pipe for heat network supply and return water, and a series-parallel cascade transmission and distribution pipeline system that combines zoning in series and parallel connection of users within the same type of area; among them, the factory process waste heat is used as the main heat source, and a factory radiator 1 for dissipating process waste heat is provided. The cooling water inlet of the factory radiator 1 is connected to the outlet of the process cooling pump P1. The inlet of the process cooling pump P1 is respectively connected to the outlet of the V2 electric valve and the outlet of the V3 electric valve. The inlet of the V2 electric valve is connected to the outlet of the cooling tower 4. In addition to being connected to the inlet of the cooling tower 4 through the V1 electric valve, the cooling water outlet of the factory radiator 1 is also connected to the inlet of the solar collector 2 through the V5 electric valve; the outlet of the solar collector 2 is connected to the inlet of the V6 electric valve. The cooling water outlet of the factory radiator 1 is also connected to the outlet of the V6 electric valve through the V4 electric valve. The pipeline of its mixed water is respectively connected to the inlet of the V8 electric valve and the inlet of the low-temperature large-temperature-difference energy storage tank 5 through the V7 electric valve. The outlet of the low-temperature large-temperature-difference energy storage tank 5 is connected to the inlet of the energy storage booster pump P2. The outlet of the energy storage booster pump P2 is respectively connected to the inlet of the V10 electric valve and the outlet of the V8 electric valve through the V9 electric valve; the outlet of the V8 electric valve is also connected to the heating water inlet of the hybrid end user 6. The heating water outlet of the hybrid end user 6 is respectively connected to the outlet of the V10 electric valve, the inlet of the V11 electric valve, and the inlet of the V12 electric valve;The water outlet of the V12 electric valve is connected to the heating water inlet of the floor heating heat user 7. The heating water outlet of the floor heating heat user 7 is connected to the water outlet of the V11 electric valve, the water inlet of the V14 electric valve, and the water inlet of the V15 electric valve through the V13 electric valve. The water outlet of the V15 electric valve is respectively connected to the water inlet of the V16 electric valve and the water inlet of the V17 electric valve of the hybrid terminal water loop heat pump user U1. The hybrid terminal water loop heat pump user U1 is also provided with a high-temperature heat source type water loop heat pump 8, a first user heating pump 85, a hybrid terminal heat exchanger 86, and a V18 electric valve. The high-temperature heat source type water loop heat pump 8 includes a high-temperature evaporator 81, a high-temperature compressor 82, a high-temperature condenser 83, a high-temperature expansion valve 84, and its connecting pipeline components. The water inlet of the high-temperature evaporator 81 is connected to the water outlet of the V17 electric valve, and the water outlet of the high-temperature evaporator 81 is connected to the water inlet of the V18 electric valve. The water outlet of the high-temperature condenser 83 is connected to the heating water inlet of the hybrid terminal heat exchanger 86 through the first user heating pump 85, and the water inlet of the high-temperature condenser 83 is connected to the heating water outlet of the hybrid terminal heat exchanger 86. The water outlet of the V18 electric valve is respectively connected to the water outlet of the V16 electric valve, the water outlet of the V23 electric valve, the water inlet of the V19 electric valve, and the water inlet of the V20 electric valve of the floor heating water loop heat pump user U2. The floor heating water loop heat pump user U2 is also provided with a low-temperature heat source type water loop heat pump 9, a second user heating pump 95, a floor heating heat exchanger 96, and a V21 electric valve. The low-temperature heat source type water loop heat pump 9 includes a low-temperature evaporator 91, a low-temperature compressor 92, a low-temperature condenser 93, a low-temperature expansion valve 94, and its connecting pipeline components. The water inlet of the low-temperature evaporator 91 is connected to the water outlet of the V20 electric valve, and the water outlet of the low-temperature evaporator 91 is connected to the water inlet of the V21 electric valve. The water outlet of the low-temperature condenser 93 is connected to the heating water inlet of the floor heating heat exchanger 96 through the second user heating pump 95, and the water inlet of the low-temperature condenser 93 is connected to the heating water outlet of the floor heating heat exchanger 96. The water outlet of the V21 electric valve is respectively connected to the water outlet of the V19 electric valve, the water inlet of the V22 electric valve, the water inlet of the V3 electric valve, and the water outlet of the V14 electric valve. The water outlet of the V22 electric valve is connected to the water inlet of the ground source heat exchanger 3. The water outlet of the ground source heat exchanger 3 is respectively connected to the water inlet of the V23 electric valve and the water inlet of the V24 electric valve through the ground source circulation pump P3. The water outlet of the V24 electric valve is connected to the water outlet of the factory radiator 1.;

[0046] The hybrid terminal heat users 6 include several groups of heat users in the form of radiator, fan coil unit or floor heating heat supply terminals. The connection relationship of the heating water branch between each heat user is parallel, that is, the heat user groups of the hybrid terminal heat users 6 share a common heating water supply main pipe and a return water main pipe; the floor heating heat users 7 include several groups of heat users in the form of floor heating heat supply terminals. The connection relationship of the heating water branch between each heat user is parallel, that is, the heat user groups of the floor heating heat users 7 share a common heating water supply main pipe and a return water main pipe; the hybrid terminal water loop heat pump users U1 include several groups of heat users in the form of radiator, fan coil unit or floor heating heat supply terminals. Each heat user is equipped with an independent high-temperature heat source type water loop heat pump heating system, and the connection relationship of the low-temperature surplus hot water branch between each heat user is parallel, that is, the heat user groups of the hybrid terminal water loop heat pump users U1 share a common low-temperature surplus hot water supply main pipe and a return water main pipe; the floor heating water loop heat pump users U2 include several groups of heat users in the form of floor heating heat supply terminals. Each heat user is equipped with an independent low-temperature heat source type water loop heat pump heating system, and the connection relationship of the low-temperature surplus hot water branch between each heat user is parallel, that is, the heat user groups of the floor heating water loop heat pump users U2 share a common low-temperature surplus hot water supply main pipe and a return water main pipe.

[0047] The pipe end of a common heating water supply main pipe shared by the heat user groups of the hybrid terminal heat users 6 is truncated, and the total outlet of a common heating water return main pipe is connected to the total inlet of a common heating water supply main pipe shared by the heat user groups of the floor heating heat users 7. That is, the heating network water of the hybrid terminal heat users 6 and the floor heating heat users 7 forms a series relationship as a whole; the pipe end of a common heating water supply main pipe shared by the heat user groups of the floor heating heat users 7 is truncated, and the total outlet of a common heating water return main pipe is connected to the total inlet of a common low-temperature surplus hot water supply main pipe shared by the heat user groups of the hybrid terminal water loop heat pump users U1. That is, the heating network water of the floor heating heat users 7 and the low-temperature heat source water of the hybrid terminal water loop heat pump users U1 form a series relationship as a whole; the pipe end of a common low-temperature heat source water supply main pipe shared by the heat user groups of the hybrid terminal water loop heat pump users U1 is truncated, and the total outlet of a common low-temperature heat source water return main pipe is connected to the total inlet of a common low-temperature surplus hot water supply main pipe shared by the heat user groups of the floor heating water loop heat pump users U2. That is, the low-temperature heat source water of the hybrid terminal water loop heat pump users U1 and the low-temperature heat source water of the floor heating water loop heat pump users U2 form a series relationship as a whole.

[0048] The ground source heat exchanger 3 includes several distributed shallow geothermal energy heat exchangers, which adopt the form of buried pipe heat exchangers, groundwater well group forms, or large-flow surface water and seawater forms; the low-temperature heat source water inlet pipe and outlet pipe are respectively communicated with the low-temperature heat source water outlet pipe and inlet pipe of the floor heating water-loop heat pump user U2 during the heating period, and are communicated with the cooling circulating water outlet pipe and inlet pipe of the factory radiator 1 during the non-heating period.

[0049] The factory radiator 1 includes one or several heat exchangers for process heat dissipation in high-energy-consuming factories, and these heat exchangers for process heat dissipation can be located in one or several factories.

[0050] The solar collector 2 includes one or several groups of solar collectors. When several groups are set, their geographical locations can be arranged in a centralized or decentralized manner.

[0051] The temperature of the supply main pipe of the low-temperature large-temperature-difference heat network water distribution subsystem is 40 - 50 °C, and the temperature of the return main pipe is 4 - 7 °C. Among them, the temperature of the heating water supply branch main pipe of the hybrid terminal heat user 6 is 40 - 50 °C, the temperature of the heating water supply branch main pipe of the floor heating heat user 7 is 35 - 38 °C, the temperature of the low-temperature heat source water supply branch main pipe of the hybrid terminal water-loop heat pump user U1 is 30 - 33 °C, the temperature of the low-temperature heat source water supply branch main pipe of the floor heating water-loop heat pump user U2 is 10 - 12 °C, and the temperature of the low-temperature heat source water return branch main pipe of the floor heating water-loop heat pump user U2 is 4 - 7 °C; the temperature of the low-temperature heat source water outlet pipe of the ground source heat exchanger 3 is 7 - 15 °C, the temperature of the cooling water outlet of the factory radiator 1 is 35 - 40 °C, and the temperature of the water outlet of the solar collector 2 is 40 - 50 °C.

[0052] The large-temperature-difference flexible heating system based on low-grade heat sources and water-loop heat pumps is characterized in that the specific working method of the large-temperature-difference flexible heating system is as follows.

[0053] (I) The working method on the heat source supply side during the heating period is as follows.

[0054] I. The heat network water heating method and process of the factory radiator 1 are as follows: The V1 electric valve and V2 electric valve are closed or closed slightly, V24 is closed, V3 is opened, the low-temperature heat source water return from the floor heating water-loop heat pump user U2 is sent to the water inlet of the process cooling pump P1 through the V21 electric valve, and after being pressurized by the process cooling pump P1, it is sent to the factory radiator 1 and heated to 35 - 40 °C.

[0055] II. The heat network water heating method and process of the solar collector 2 are as follows: The V4 electric valve is in an adjustment state, the V5 electric valve and V6 electric valve are opened during the day when there is sunlight and closed when there is no sunlight, the V8 electric valve is in an adjustment state, the heat network water outlet from the factory radiator 1 enters the solar collector 2 through the V5 electric valve for reheating, and the water temperature is raised to 40 - 50 °C.

[0056] III. The heat network water heat storage method and process of the low-temperature large temperature difference heat storage tank 5 are as follows: The V7 electric valve is opened when heat storage is required, otherwise it is closed. When the low-temperature large temperature difference heat storage tank 5 needs to supply heat, the energy storage booster pump P2 is started, otherwise it is closed.

[0057] IV. The low-temperature heat source water heating method and process of the ground source heat exchanger 3 are as follows: The ground source heat exchanger 3 serves as a peak shaving heat source heater and is only used to heat the low-temperature heat source water outlet of the floor heating water ring heat pump user U2. When heating of the low-temperature heat source water is required, the V22 electric valve is opened, the V23 electric valve is opened, the ground source circulation pump P3 is started, and the water outlet of the ground source heat exchanger 3 is sent by the ground source circulation pump P3 to the low-temperature evaporator 91 of the low-temperature heat source type water ring heat pump 9. After releasing heat, it returns to the water inlet of the ground source heat exchanger 3.

[0058] (2) The working method on the heating user side during the heating period is as follows.

[0059] I. The heat supply method and process of the hybrid terminal heat user 6 are as follows: The heat network water supply from the V8 electric valve and the V9 electric valve is sent into the heating water supply branch main pipe of the hybrid terminal heat user 6 for heating, and then sent to the downstream floor heating heat user 7. Among them, the heating water flow rate and heat supply amount of the hybrid terminal heat user 6, as well as the heat network water flow rate and heat supply amount from the low-temperature large temperature difference heat storage tank 5, are adjusted by the opening degrees of the V9 electric valve and the V10 electric valve.

[0060] II. The heat supply method and process of the floor heating heat user 7 are as follows: The heat network water from the heating water return branch main pipe of the hybrid terminal heat user 6 and the bypass heat network water from the V9 electric valve and the V10 electric valve are mixed and then sent into the heating water supply branch main pipe of the floor heating heat user 7 for heating, and then sent to the downstream hybrid terminal water ring heat pump user U1. Among them, the heating water flow rate and heat supply amount of the floor heating heat user 7 are adjusted by the opening degrees of the V11 electric valve, the V12 electric valve and the V13 electric valve.

[0061] III. The heat supply method and process of the hybrid terminal water ring heat pump user U1 are as follows: The V15 electric valve is opened, and the heat network water from the heating water return branch main pipe of the floor heating heat user 7 is sent into the low-temperature heat source water supply branch main pipe of the hybrid terminal water ring heat pump user U1, and is absorbed and cooled by the high-temperature evaporator 81 of the high-temperature heat source type water ring heat pump 8, and then sent to the downstream floor heating water ring heat pump user U2. Among them, the low-temperature heat source water flow rate and heat exchange amount of the high-temperature evaporator 81 are adjusted by the opening degrees of the V16 electric valve, the V17 electric valve and the V18 electric valve. The heating water outlet of the high-temperature condenser 83 of the high-temperature heat source type water ring heat pump 8 is sent to the hybrid terminal heat exchanger 86 for heating by the first user heating pump 85, and after cooling, it returns to the heating water inlet of the high-temperature condenser 83 to continue circulating and heating.

[0062] IV. The heating method and process for the floor heating water - loop heat pump user U2 are as follows: The low - temperature surplus hot water in the return branch main pipe of the low - temperature heat source water of the hybrid - end water - loop heat pump user U1 is mixed with the low - temperature heat source water outlet from the ground - source heat exchanger 3, and then sent into the supply branch main pipe of the low - temperature heat source water of the floor heating water - loop heat pump user U2. It is absorbed and cooled by the low - temperature evaporator 91 of the low - temperature heat source type water - loop heat pump 9, and then returns to the heat source and enters the system. Among them, the opening degrees of the V19 electric valve, V20 electric valve, and V21 electric valve are used to adjust the flow rate and heat transfer amount of the low - temperature heat source water of the low - temperature evaporator 91. The heating water outlet of the low - temperature condenser 93 of the high - temperature heat source type water - loop heat pump 8 is sent to the floor heating heat exchanger 96 for heating by the second user heating pump 95, and after cooling, it returns to the heating water inlet of the low - temperature condenser 93 to continue circulating and heating.

[0063] V. The heat supply regulation and circulating water flow matching method among each heating - end heat - user groups: The heat supply and heat - network water flow of the hybrid - end heat user 6 are adjusted by the opening degrees of the V9 electric valve and V10 electric valve. The heat supply and heat - network water flow of the floor heating heat user 7 are adjusted by the opening degree of the V11 electric valve. The heat supply and low - temperature heat source water flow of the hybrid - end water - loop heat pump user U1 are adjusted by the opening degree of the V16 electric valve. The heat supply and low - temperature heat source water flow of the floor heating water - loop heat pump user U2 are adjusted by the opening degree of the V19 electric valve and the flow rate of the ground - source circulation pump P3. When the heating load requirements and the required low - temperature heat source water flow of the hybrid - end water - loop heat pump user U1 and the floor heating water - loop heat pump user U2 decrease, the V14 electric valve is opened and adjusted by its opening degree.

[0064] (III)The working method during the non - heating period is as follows.

[0065] I. The circulating cooling working method of the factory radiator 1: Open the process cooling pump P1, V1 electric valve, and V2 electric valve, cool the cooling water outlet of the factory radiator 1 through the cooling tower 4, and return it to the cooling water inlet of the factory radiator 1.

[0066] II. One of the soil temperature recovery working methods of the ground - source heat exchanger 3: Preferably, the method of cooling the hybrid - end water - loop heat pump user U1 and the floor heating water - loop heat pump user U2 is adopted. When cooling is required in summer, close the V3 electric valve and V24 electric valve, open the V22 electric valve and V23 electric valve. The low - temperature heat source water outlet of the ground - source heat exchanger 3 is sent by the ground - source circulation pump P3 to the condensers of the water - loop heat pumps of the hybrid - end water - loop heat pump user U1 and the floor heating water - loop heat pump user U2 or directly into the terminal heat exchanger to cool the indoor air on the premise that no unexpected condensate water is generated at the terminal heat exchanger. The waste heat circulating water is heated and then returns to the ground - source heat exchanger 3 to heat the underground soil, and the cooled low - temperature heat source water continues to circulate and heat.

[0067] II. The second method for the soil temperature recovery of the ground source heat exchanger 3: Secondly, adopt the method of heating with the waste heat of the factory radiator 1; open the V22 electric valve and the V24 electric valve, close the V23 electric valve, and a part of the cooling water from the outlet of the factory radiator 1 is sent into the ground source heat exchanger 3 to heat the underground soil, and the cooled cooling water returns to the process cooling pump P1 and continues to circulate and heat up.

[0068] (IV) Adopt a dedicated intelligent heat network control system to monitor the operating parameters of the large temperature difference flexible heating system based on low-grade heat sources and water ring heat pumps, and perform annual real-time automatic control and adjustment on the above heat storage and heat extraction processes.

[0069] (V) The behavior energy-saving heating method driven by economic benefits: Adopt a large temperature difference flexible heating system based on low-grade heat sources and water ring heat pumps. The thermal company undertakes the construction of the low-grade combined clean heat source subsystem, the low-temperature large temperature difference heat network water transmission and distribution subsystem, and the water ring heat pump body. Its construction cost is usually basically equivalent to or slightly exceeds the legal heat source / heat network / courtyard pipe network supporting fees. The excess investment can be recovered through heating service charges. The heating company only needs to bear the power consumption cost of the low-temperature heat source water circulation pump of the water ring heat pump, and the power consumption costs of the indoor water ring heat pump host and the heating system are borne by the final heat users themselves. The heat users can carry out room-by-room heating and time-of-use heating through independent control, and greatly reduce the heating energy consumption and its power consumption, greatly reduce the low-temperature heat source water heat load and heat source heat extraction demand in the entire heating area, and greatly reduce the energy consumption of the central heating system as a whole.

[0070] It should be noted that the specific application mode of this patent is not limited to the specific description of the above embodiments. Any simple deformation application based on this, such as choosing not to set up a solar heater or a ground source heat exchanger; not distinguishing the mixing terminal and the floor heating terminal types for heat users; not distinguishing the high-temperature waste hot water type and the low-temperature waste hot water type for water ring heat pumps; simple deformations of each heat source device, energy storage tank, heat user and their connecting pipelines, etc., can be considered to fall within the protection scope of this patent.

Claims

1. A large temperature difference flexible heating system based on low-grade heat source and water ring heat pump includes three parts: low-grade joint clean heat source subsystem, low-temperature large temperature difference heating terminal heat user group, and low-temperature large temperature difference heat network water distribution subsystem. It is characterized by: The low-grade combined clean heat source subsystem includes heat exchange equipment and energy storage equipment for factory process waste heat, solar energy and geothermal energy. The low-temperature and large temperature difference heating terminal heat user group includes mixed terminal heat users (6), floor heating heat users (7), mixed terminal water ring heat pump users (U1) and floor heating water ring heat pump users (U2). The low-temperature and large temperature difference heat network water transmission and distribution subsystem includes a heat network supply and return water double-line main pipe, and a mixed cascade transmission and distribution pipeline system in which the heat users in the same area are connected in parallel in series with the partitions. The factory process waste heat is used as the main heat source, and a factory heat release device (1) is provided to release the process waste heat. The cooling water inlet of the factory heat release device (1) is connected to the water outlet of the process cooling pump (P1). The water inlet of the process cooling pump (P1) is connected to the water outlet of the V2 electric valve and the water outlet of the V3 electric valve respectively. The water inlet of the V2 electric valve is connected to the outlet of the cooling tower (4). In addition to being connected to the water inlet of the cooling tower (4) through the V1 electric valve, the cooling water outlet of the factory heat release device (1) is also connected to the water inlet of the solar collector (2) through the V5 electric valve. The water outlet of the solar collector (2) is connected to the water inlet of the V6 electric valve. ) is also connected to the outlet of the V6 electric valve through the V4 electric valve, and its mixed water pipeline is respectively connected to the water inlet of the V8 electric valve and the water inlet of the low-temperature and large temperature difference energy storage tank (5) through the V7 electric valve. The water outlet of the low-temperature and large temperature difference energy storage tank (5) is connected to the water inlet of the energy storage booster pump (P2). The water outlet of the energy storage booster pump (P2) is respectively connected to the water inlet of the V10 electric valve and the water outlet of the V8 electric valve through the V9 electric valve. The water outlet of the V8 electric valve is also connected to the heating water inlet of the mixed terminal heat user (6). The heating water outlet of the mixed terminal heat user (6) is respectively connected to the water outlet of the V10 electric valve and the water outlet of the V11 electric valve. The water inlet of the electric valve is connected to the water inlet of the V12 electric valve; the water outlet of the V12 electric valve is connected to the heating water inlet of the floor heating heat user (7); the heating water outlet of the floor heating heat user (7) is connected to the water outlet of the V11 electric valve through the V13 electric valve, connected to the water inlet of the V14 electric valve, and connected to the water inlet of the V15 electric valve; the water outlet of the V15 electric valve is respectively connected to the water inlet of the V16 electric valve and the water inlet of the V17 electric valve of the mixed terminal water ring heat pump user (U1); the mixed terminal water ring heat pump user (U1) is also provided with a high temperature heat source type water ring heat pump (8), a first user heating pump (85), and a mixed terminal exchange heat exchanger (86), V18 electric valve, wherein the high-temperature heat source type water ring heat pump (8) comprises a high-temperature evaporator (81), a high-temperature compressor (82), a high-temperature condenser (83), a high-temperature expansion valve (84) and connecting pipeline components thereof, wherein the water inlet of the high-temperature evaporator (81) is connected to the water outlet of the V17 electric valve, the water outlet of the high-temperature evaporator (81) is connected to the water inlet of the V18 electric valve, the water outlet of the high-temperature condenser (83) is connected to the heating water inlet of the mixing terminal heat exchanger (86) through the first user heating pump (85), and the water inlet of the high-temperature condenser (83) is connected to the heating water outlet of the mixing terminal heat exchanger (86);The water outlet of the V18 electric valve is respectively connected to the water outlet of the V16 electric valve, connected to the water outlet of the V23 electric valve, connected to the water inlet of the V19 electric valve, and connected to the water inlet of the V20 electric valve of the floor heating water ring heat pump user (U2). The floor heating water ring heat pump user (U2) is also provided with a low-temperature heat source type water ring heat pump (9), a second user heating pump (95), a floor heating heat exchanger (96), and a V21 electric valve. The low-temperature heat source type water ring heat pump (9) includes a low-temperature evaporator (91), a low-temperature compressor (92), a low-temperature condenser (93), a low-temperature expansion valve (94) and connecting pipeline components thereof. The water inlet of the low-temperature evaporator (91) is connected to the water outlet of the V20 electric valve, and the water outlet of the low-temperature evaporator (91) is connected to the V21 electric valve. The water inlet of the low-temperature condenser (93) is connected to the water inlet of the floor heating heat exchanger (96) through the second user heating pump (95), and the water inlet of the low-temperature condenser (93) is connected to the heating water outlet of the floor heating heat exchanger (96); the water outlet of the V21 electric valve is respectively connected to the water outlet of the V19 electric valve, the water inlet of the V22 electric valve, the water inlet of the V3 electric valve, and the water outlet of the V14 electric valve; the water outlet of the V22 electric valve is connected to the water inlet of the ground source heat exchanger (3), the water outlet of the ground source heat exchanger (3) is respectively connected to the water inlet of the V23 electric valve and the water inlet of the V24 electric valve through the ground source circulation pump (P3), and the water outlet of the V24 electric valve is connected to the water outlet of the factory heat radiator (1). ; 2. The large temperature difference flexible heating system based on low-grade heat source and water ring heat pump as claimed in claim 1 is characterized in that The mixed terminal heat user (6) includes a plurality of heat user groups in the form of radiators, fan coil units or floor heating heating terminals, and the heating water branch connection relationship between each heat user is in parallel, that is, the heat user group of the mixed terminal heat user (6) shares a heating water supply branch pipe and a return branch pipe; the floor heating heat user (7) includes a plurality of heat user groups in the form of floor heating heating terminals, and the heating water branch connection relationship between each heat user is in parallel, that is, the heat user group of the floor heating heat user (7) shares a heating water supply branch pipe and a return branch pipe; the mixed terminal water ring heat pump user (U1) includes a plurality of heat user groups in the form of radiators, fan coil units or floor heating heating terminals The form of heat user groups, each heat user is equipped with an independent high-temperature heat source water ring heat pump heating system, and the low-temperature waste hot water branch connection relationship between each heat user is parallel, that is, the heat user group of the mixed terminal water ring heat pump user (U1) shares a low-temperature waste hot water supply branch pipe and a return branch pipe; the floor heating water ring heat pump user (U2) includes several heat user groups using the floor heating heating terminal form, each heat user is equipped with an independent low-temperature heat source water ring heat pump heating system, and the low-temperature waste hot water branch connection relationship between each heat user is parallel, that is, the heat user group of the floor heating water ring heat pump user (U2) shares a low-temperature waste hot water supply branch pipe and a return branch pipe.

3. The large temperature difference flexible heating system based on low-grade heat source and water ring heat pump as claimed in claim 2 is characterized in that The pipe end of a heating water supply branch pipe shared by the heat user group of the mixed terminal heat user (6) is cut off, and the total outlet of a shared heating water return branch pipe is connected to the total inlet of a heating water supply branch pipe shared by the heat user group of the floor heating heat user (7), that is, the heating network water of the mixed terminal heat user (6) and the floor heating heat user (7) forms a series relationship as a whole; the pipe end of a heating water supply branch pipe shared by the heat user group of the floor heating heat user (7) is cut off, and the total outlet of a shared heating water return branch pipe is connected to a low-temperature waste hot water shared by the heat user group of the mixed terminal water ring heat pump user (U1). The total inlet of the water supply branch pipe is connected, that is, the hot network water of the floor heating heat user (7) and the low-temperature heat source water of the mixed terminal water ring heat pump user (U1) form a series relationship as a whole; the pipe end of a low-temperature heat source water supply branch pipe shared by the heat user group of the mixed terminal water ring heat pump user (U1) is cut off, and the total outlet of a shared low-temperature heat source water return branch pipe is connected to the total inlet of a low-temperature waste hot water supply branch pipe shared by the heat user group of the floor heating water ring heat pump user (U2), that is, the low-temperature heat source water of the mixed terminal water ring heat pump user (U1) and the low-temperature heat source water of the floor heating water ring heat pump user (U2) form a series relationship as a whole.

4. The large temperature difference flexible heating system based on low-grade heat source and water ring heat pump as claimed in claim 1 is characterized in that The ground source heat exchanger (3) comprises a plurality of distributed shallow geothermal heat exchangers, which adopt a buried pipe heat exchanger type, a groundwater well group type or a large flow surface water and seawater type; its low-temperature heat source water inlet pipe and outlet pipe are respectively connected to the low-temperature heat source water outlet pipe and inlet pipe of the floor heating water ring heat pump user (U2) during the heating period, and are connected to the cooling circulation water outlet pipe and inlet pipe of the factory heat emitter (1) during the non-heating period.

5. The large temperature difference flexible heating system based on low-grade heat source and water ring heat pump as claimed in claim 1 is characterized in that The factory heat emitter (1) comprises one or several process heat exchangers for heat dissipation in high energy consumption factories, and these process heat exchangers for heat dissipation can be located in one or several factories.

6. The large temperature difference flexible heating system based on low-grade heat source and water ring heat pump according to claim 1 is characterized in that The solar thermal collector (2) comprises one group or several groups of solar thermal collectors. When several groups are provided, their geographical locations can be arranged in a centralized manner or in a decentralized manner.

7. The large temperature difference flexible heating system based on low-grade heat source and water ring heat pump as claimed in claim 1 is characterized in that The water supply main pipe temperature of the low-temperature large temperature difference heat network water distribution subsystem is 40-50°C, and the return water main pipe temperature is 4-7°C. The heating water supply branch pipe temperature of the mixed terminal heat user (6) is 40-50°C, the heating water supply branch pipe temperature of the floor heating heat user (7) is 35-38°C, the low-temperature heat source water supply branch pipe temperature of the mixed terminal water ring heat pump user (U1) is 30-33°C, the low-temperature heat source water supply branch pipe temperature of the floor heating water ring heat pump user (U2) is 10-12°C, and the low-temperature heat source water return branch pipe temperature of the floor heating water ring heat pump user (U2) is 4-7°C; the low-temperature heat source water outlet pipe temperature of the ground source heat exchanger (3) is 7-15°C, the cooling water outlet temperature of the factory radiator (1) is 35-40°C, and the outlet water temperature of the solar collector (2) is 40-50°C.

8. A large temperature difference flexible heating system based on low-grade heat source and water ring heat pump, characterized by The specific working method of the large temperature difference flexible heating system is as follows:

1. The working methods of the heat source supply side during the heating period are as follows: I. The method and process of heating the hot water network of the factory radiator (1) are as follows: the V1 electric valve and the V2 electric valve are turned down or closed, V24 is closed, V3 is opened, and the low-temperature heat source water return water from the floor heating water ring heat pump user (U2) is sent to the water inlet of the process cooling pump (P1) through the V21 electric valve, and then pressurized by the process cooling pump (P1) and sent to the factory radiator (1) to be heated to 35-40°C; II. The method and process of heating the hot water network of the solar thermal collector (2) are as follows: the V4 electric valve is in a regulating state, the V5 electric valve and the V6 electric valve are opened when there is sunlight during the day and closed when there is no sunlight, the V8 electric valve is in a regulating state, and the hot water network outlet from the factory heat release device (1) enters the solar thermal collector (2) through the V5 electric valve for reheating, and the water temperature is raised to 40-50°C; III. The method and process of heat storage of hot water in the low-temperature and large temperature difference energy storage tank (5) are as follows: the V7 electric valve is opened when heat storage is required, otherwise it is closed; when the low-temperature and large temperature difference energy storage tank (5) needs to supply heat, the energy storage booster pump (P2) is turned on, otherwise it is closed; IV. The method and process for heating low-temperature heat source water of the ground source heat exchanger (3) are as follows: the ground source heat exchanger (3) is used as a peak-shaving heat source heater and is only used to heat the low-temperature heat source water outlet of the floor heating water ring heat pump user (U2). When the low-temperature heat source water needs to be heated, the V22 electric valve is opened, the V23 electric valve is opened, the ground source circulation pump (P3) is turned on, and the outlet water of the ground source heat exchanger (3) is sent to the low-temperature evaporator (91) of the low-temperature heat source water ring heat pump (9) by the ground source circulation pump (P3), and returns to the water inlet of the ground source heat exchanger (3) after releasing heat; (II) The working method of heating heat user side during the heating period is as follows: I. The heating method and process of the mixed terminal heat user (6) are as follows: the heating network water supply from the V8 electric valve and the V9 electric valve is sent to the heating water supply branch pipe of the mixed terminal heat user (6) for heating, and then sent to the downstream floor heating heat user (7), wherein the heating water flow and heating supply of the mixed terminal heat user (6) and the heating network water flow and heating supply from the low-temperature large temperature difference energy storage tank (5) are adjusted by the opening of the V9 electric valve and the V10 electric valve; II. The heating method and process of the floor heating heat user (7) are as follows: the hot network water from the heating water return branch pipe of the mixed terminal heat user (6) and the bypass hot network water from the V9 electric valve and the V10 electric valve are mixed and sent to the heating water supply branch pipe of the floor heating heat user (7) for heating, and then sent to the downstream mixed terminal water ring heat pump user (U1), wherein the heating water flow and heating amount of the floor heating heat user (7) are adjusted by the opening of the V11 electric valve, the V12 electric valve and the V13 electric valve; III. The heating method and process of the mixed terminal water ring heat pump user (U1) are as follows: the V15 electric valve is opened, and the hot network water from the heating water return branch pipe of the floor heating heat user (7) is sent to the low-temperature heat source water supply branch pipe of the mixed terminal water ring heat pump user (U1), and is cooled by the high-temperature evaporator (81) of the high-temperature heat source water ring heat pump (8), and then sent to the downstream floor heating water ring heat pump user (U2), wherein the low-temperature heat source water flow and heat exchange capacity of the high-temperature evaporator (81) are adjusted by the opening of the V16 electric valve, the V17 electric valve and the V18 electric valve, and the heating water outlet of the high-temperature condenser (83) of the high-temperature heat source water ring heat pump (8) is sent to the mixed terminal heat exchanger (86) by the first user heating pump (85) for heating, and after cooling, returns to the heating water inlet of the high-temperature condenser (83) to continue circulating heating; IV. The heating method and process of the floor heating water ring heat pump user (U2) are as follows: the low-temperature waste hot water of the low-temperature heat source water return branch pipe of the mixing end water ring heat pump user (U1) is mixed with the low-temperature heat source water outlet from the ground source heat exchanger (3), and then sent to the low-temperature heat source water supply branch pipe of the floor heating water ring heat pump user (U2), and the low-temperature evaporator (91) of the low-temperature heat source water ring heat pump (9) absorbs heat and cools down, and then returns to the heat source to enter the system, wherein the low-temperature heat source water flow rate and heat exchange amount of the low-temperature evaporator (91) are adjusted by the opening of the V19 electric valve, the V20 electric valve and the V21 electric valve, and the heating water outlet of the low-temperature condenser (93) of the high-temperature heat source water ring heat pump (8) is sent to the floor heating heat exchanger (96) by the second user heating pump (95) for heating, and after cooling, returns to the heating water inlet of the low-temperature condenser (93) to continue circulating heating; V. Method for adjusting the heating capacity and matching the circulating water flow between the heat user groups at the heating end: the heating capacity and the water flow of the heating network of the mixed heat user (6) are adjusted by the opening of the V9 electric valve and the V10 electric valve, the heating capacity and the water flow of the heating network of the floor heating heat user (7) are adjusted by the opening of the V11 electric valve, the heating capacity and the low-temperature heat source water flow of the mixed water ring heat pump user (U1) are adjusted by the opening of the V16 electric valve, the heating capacity and the low-temperature heat source water flow of the floor heating water ring heat pump user (U2) are adjusted by the opening of the V19 electric valve and the flow of the ground source circulation pump (P3), when the heating load demand and the required low-temperature heat source water flow of the mixed water ring heat pump user (U1) and the floor heating water ring heat pump user (U2) decrease, the V14 electric valve is opened and adjusted by its opening; (III) The working methods during the non-heating period are as follows: I. Circulation cooling working method of the factory radiator (1): Open the process cooling pump (P1), V1 electric valve and V2 electric valve, cool the cooling water outlet of the factory radiator (1) through the cooling tower (4), and return it to the cooling water inlet of the factory radiator (1); II. One of the working methods for restoring the soil temperature of the ground source heat exchanger (3): preferentially adopt the method of cooling the mixed terminal water ring heat pump user (U1) and the floor heating water ring heat pump user (U2). When cooling is required in summer, close the V3 electric valve and the V24 electric valve, open the V22 electric valve and the V23 electric valve, and the low-temperature heat source water outlet of the ground source heat exchanger (3) is sent by the ground source circulation pump (P3) to the condenser of the water ring heat pump of the mixed terminal water ring heat pump user (U1) and the floor heating water ring heat pump user (U2) or directly to the terminal heat exchanger. Under the premise that the terminal heat exchanger does not produce unexpected condensed water, the indoor air is cooled, and the waste heat circulation water is heated and returned to the ground source heat exchanger (3) to heat the underground soil. The cooled low-temperature heat source water continues to circulate and heat; II. Second working method of soil temperature recovery of ground source heat exchanger (3): Secondly, the waste heat heating method of the factory heat release device (1) is adopted; the V22 electric valve and the V24 electric valve are opened, and the V23 electric valve is closed. A part of the cooling water from the outlet of the factory heat release device (1) is sent to the ground source heat exchanger (3) to heat the underground soil. The cooled cooling water returns to the process cooling pump (P1) and continues to circulate and heat; (iv) using a dedicated intelligent heat network control system to monitor the operating parameters of the large temperature difference flexible heating system based on low-grade heat sources and water ring heat pumps, and to automatically control and adjust the above-mentioned heat storage and heat extraction processes in real time throughout the year; (V) Behavioral energy-saving heating method driven by economic benefits: adopt a large temperature difference flexible heating system based on low-grade heat source and water ring heat pump, and the heating company shall bear the construction of the low-grade combined clean heat source subsystem, low-temperature large temperature difference heat network water distribution subsystem and water ring heat pump body. The construction cost is usually basically equivalent to or slightly higher than the statutory heat source / heat network / courtyard pipe network supporting fees, and the excess investment can be recovered through heating service charges. The heating company only needs to bear the electricity consumption cost of the low-temperature heat source water circulation pump of the water ring heat pump. The electricity consumption cost of the indoor water ring heat pump host and heating system shall be borne by the final heat user. The heat user can carry out room-by-room heating and time-by-time heating through autonomous control and greatly reduce the heating energy consumption and power consumption, greatly reduce the low-temperature heat source water heat load and heat source heating demand in the entire heating area, and greatly reduce the energy consumption of the centralized heating system as a whole.

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