Large-temperature-difference heating system

Abstract

The utility model discloses a large-temperature-difference heating system which is used for energy transmission between a heat source plant and a user and comprises a first heat exchange station and a second heat exchange station which are arranged between the heat source plant and the user, and a first net pipe is arranged between the first heat exchange station and the second heat exchange station. A first network pipe is arranged between the first heat exchange station and the user, a second network pipe is arranged between the second heat exchange station and the user, the first network pipe comprises a first water supply pipe and a first water return pipe, the second network pipe comprises a second water supply pipe and a second water return pipe, and a heat storage device, a CO2 heat pump and a first evaporator of a water source heat pump are sequentially connected between the first water supply pipe and the first water return pipe; a condenser of the water source heat pump is connected between the second water supply pipe and the second water return pipe. According to the large-temperature-difference heating system, the CO2 heat pump is arranged, high energy efficiency can be kept at the low evaporation temperature, the overall energy efficiency of the system is improved, the heat storage device is arranged, the heat storage and release mode of the heat storage device is utilized, the system operation electric power cost is the lowest, and the system operation economical efficiency can be improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of heating, and in particular relates to a large temperature difference heating system. Background Art

[0002] Cogeneration is the main heat source for centralized heating in northern my country. With the rapid development of China's social economy, the area of ​​centralized heating in cities and towns has increased rapidly. The design transmission capacity of the original heating pipeline network is difficult to meet the growth of heat load. Moreover, with the aging of the pipeline network, it is difficult to increase the water supply temperature and flow rate, and the transmission capacity is further declining.

[0003] Ordinary water source heat pumps can effectively utilize the heat of return water from a network and reduce the return water temperature of a network. They can improve the transmission and distribution capacity of the network by increasing the temperature difference between the supply and return water of a network without adding additional pipelines. However, as the return water temperature decreases, the evaporation temperature of the heat pump decreases, which will lead to a decrease in the energy efficiency of the heat pump and increase power consumption. Moreover, the electricity price is different during peak and valley periods, with high charges for peak electricity consumption and low charges for valley electricity consumption. Using heat pumps for heating during peak periods will increase electricity costs.

[0004] Therefore, it is urgent to design a large temperature difference heating system to solve the problem mentioned above that when the ordinary water source heat pump evaporates, the temperature drop will cause the heat pump energy efficiency to decrease and increase electricity consumption. The heat pump will increase electricity costs when providing heating during peak power periods. Utility Model Content

[0005] In order to solve the technical problems mentioned in the background technology that when ordinary water source heat pumps evaporate, the temperature drops, which leads to a decrease in the energy efficiency of the heat pump and an increase in electricity consumption. When the heat pumps provide heating during peak power periods, it will increase electricity costs and waste energy. A large temperature difference heating system is provided to solve the above problems.

[0006] In order to achieve the above-mentioned purpose, the specific technical scheme of the large temperature difference heating system of the utility model is as follows:

[0007] A large temperature difference heating system is used for energy transmission between a heat source plant and a user, comprising a first heat exchange station and a second heat exchange station arranged between the heat source plant and the user, a first network pipe is arranged between the first heat exchange station and the second heat exchange station, and a second network pipe is arranged between the second heat exchange station and the user, the first network pipe comprises a first water supply pipe and a first water return pipe, the second network pipe comprises a second water supply pipe and a second water return pipe, a heat storage device, a CO2 heat pump and a first evaporator of a water source heat pump are connected in sequence between the first water supply pipe and the first water return pipe, the first evaporator of the water source heat pump cools the return water in the first return pipe by heat exchange and then flows back to the CO2 heat pump, the CO2 heat pump exchanges the water and then flows to the heat storage device, a condenser of the water source heat pump is connected between the second water supply pipe and the second water return pipe, and the condenser of the water source heat pump heats the return water in the second return pipe by heat exchange and then flows back to the second water supply pipe.

[0008] Furthermore, the water source heat pump also includes a first compressor and a first throttle valve. The first evaporator, the condenser, the first compressor and the first throttle valve are connected in sequence to form a first circulation loop. The water inlet end of the first evaporator is connected to the first return pipe, the water outlet end of the first evaporator is connected to the CO2 heat pump, the water inlet end of the condenser is connected to the second return pipe, and the water outlet end of the condenser is connected to the second water supply pipe.

[0009] Furthermore, the CO2 heat pump includes a second evaporator, a gas cooler, a second compressor and a second throttle valve, which sequentially form a second circulation loop, the water inlet of the second evaporator is connected to the water outlet of the first evaporator, the water outlet of the second evaporator is connected to the low-temperature water inlet and outlet of the heat storage device, the water inlet of the gas cooler is connected to the water outlet of the first evaporator, and the water outlet of the gas cooler is connected to the high-temperature water inlet and outlet of the heat storage device.

[0010] Furthermore, the heat storage device includes a water tank, the high-temperature water inlet and outlet of the heat storage device are arranged at the top of the water tank, and the low-temperature water inlet and outlet of the heat storage device are arranged at the bottom of the water tank.

[0011] Furthermore, the heat storage device also includes a first water pipe, a second water pipe, a third water pipe, a fourth water pipe and a fifth water pipe, one end of the first water pipe is connected to the first water supply pipe, the other end of the first water pipe is connected to the first water return pipe, one end of the second water pipe is connected to the first water pipe, the other end of the second water pipe is connected to the high-temperature water inlet and outlet of the water tank, one end of the third water pipe is connected to the first water pipe, the other end of the third water pipe is connected to the low-temperature water inlet and outlet of the water tank, one end of the fourth water pipe is connected to the second water pipe, the other end of the fourth water pipe is connected to the third water pipe, one end of the fifth water pipe is connected to the first water pipe, and the other end of the fifth water pipe is connected to the fourth water pipe.

[0012] Furthermore, the heat storage device also includes a first valve, a second valve, a third valve, a fourth valve, a fifth valve, a sixth valve, a seventh valve, an eighth valve and a first water pump. The first valve, the third valve, the fifth valve and the eighth valve are arranged on the first water pipe, the second valve is arranged on the second water pipe, one end of the second water pipe is connected between the first valve and the third valve, the seventh valve is arranged on the third water pipe, one end of the third water pipe is connected between the fifth valve and the eighth valve, the fourth valve and the sixth valve are arranged on the fourth water pipe, the first water pump is arranged on the fifth water pipe, one end of the fifth water pipe is arranged between the third valve and the fifth valve, and the other end of the fifth water pipe is arranged between the fourth valve and the sixth valve.

[0013] Furthermore, it also includes a first connecting pipe and a second connecting pipe, one end of the first connecting pipe is connected to the water outlet of the first evaporator, and the other end of the first connecting pipe is connected to the water inlet of the second evaporator, one end of the second connecting pipe is connected to the water outlet of the first evaporator, and the other end of the second connecting pipe is connected to the water inlet of the gas cooler.

[0014] Furthermore, a second water pump and a first switch valve are arranged on the first connecting pipe, and a third water pump and a second switch valve are arranged on the second connecting pipe.

[0015] Furthermore, the water temperature at the outlet of the first evaporator is T1, the mass flow rate of the water inlet of the second evaporator is Q1, the water temperature at the outlet of the second evaporator is T2, the mass flow rate of the water inlet of the gas cooler is Q2, the water temperature at the outlet of the gas cooler is T3, the energy efficiency coefficient of the CO2 heat pump is COP, the water flow rate of the second evaporator is controlled by controlling the first switch valve and the second water pump, and the water flow rate of the gas cooler is controlled by controlling the second switch valve and the third water pump. The control formula is:

[0016]

[0017] Furthermore, a fourth water pump and a third switch valve are provided on the first water supply pipe, a fourth switch valve is provided on the first return water pipe, a fifth switch valve is provided on the second water supply pipe, a fifth water pump is provided on the second return water pipe, a sixth switch valve and a sixth water pump are provided between the water outlet of the condenser and the second water supply pipe, and a seventh switch valve is provided between the water inlet of the condenser and the second return water pipe.

[0018] The large temperature difference heating system of the utility model has the following advantages:

[0019] By setting up a C0: heat pump, the CO2 heat pump can maintain high energy efficiency at a low evaporation temperature, and can also make the outlet water temperature reach above 80°C. It is directly connected to the first water supply pipe for heating, and the heat storage device is used to store hot water to improve the energy efficiency of the heat pump. A heat storage device is set up to utilize the peak-valley electricity price difference. During valley electricity periods, the heat pump runs at full load to store hot water in the heat storage device. During peak electricity periods, the heat pump runs at low load or does not run, and the hot water in the heat storage device is used for heating. This can minimize the system's operating electricity cost and improve the economy of the system's operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the structure of the large temperature difference heating system of the utility model;

[0021] Figure 2 It is a structural schematic diagram of the heat storage device of the utility model.

[0022] Description of the markings in the figure:

[0023] 100, heat source plant; 200, user; 300, first heat exchange station; 400, second heat exchange station; 1, first network management: 11, first water supply pipe; 111, fourth water pump: 112, third switch valve; 12, first return pipe; 121, fourth switch valve; 2, second network management: 21, second water supply pipe: 211, fifth switch valve; 22, second return pipe; 221, fifth water pump; 3, heat storage device; 31, water tank; 32, first water pipe; 321, first valve; 322, third valve; 323, fifth valve; 324, eighth valve; 33, second water pipe; 331 , the second valve; 34, the third water pipe; 341, the seventh valve; 35, the fourth water pipe; 351, the fourth valve; 352, the sixth valve; 36, the fifth water pipe; 361, the first water pump; 4, the water source heat pump; 41, the first evaporator; 42, the condenser; 43, the first compressor; 44, the first throttle valve; 5, the CO2 heat pump; 51, the second evaporator; 52, the gas cooler; 53, the second compressor; 54, the second throttle valve; 6, the first connecting pipe; 61, the second water pump; 62, the first switch valve; 7, the second connecting pipe; 71, the third water pump; 72, the second switch valve. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model.

[0025] Those skilled in the art will appreciate that, although some embodiments herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present invention and form different embodiments. For example, in the claims, any one of the claimed embodiments may be used in any combination.

[0026] Please refer to the attached Figure 1 To Attachment Figure 2 The utility model is described in detail.

[0027] like Figure 1As shown, the large temperature difference heating system in the utility model is used for energy transmission between the heat source plant 100 and the user 200, including a first heat exchange station 300 and a second heat exchange station 400 arranged between the heat source plant 100 and the user 200, a first network pipe 1 is arranged between the first heat exchange station 300 and the second heat exchange station 400, a second network pipe 2 is arranged between the second heat exchange station 400 and the user 200, the first network pipe 1 includes a first water supply pipe 11 and a first return water pipe 12, the second network pipe 2 includes a second water supply pipe 21 and a second return water pipe 22, and by setting the first heat exchange station 300 and the second heat exchange station 400, hot water can be provided to the user 200. The first water supply pipe 11 and the first water return pipe 12 are connected in sequence to the heat storage device 3, the CO2 heat pump 5 and the first evaporator 41 of the water source heat pump 4. The first evaporator 41 of the water source heat pump 4 cools the return water in the first water return pipe 12 by heat exchange and then flows back to the CO2 heat pump 5. The CO2 heat pump 5 exchanges the water and then flows to the heat storage device 3. The condenser 42 of the water source heat pump 4 is connected between the second water supply pipe 21 and the second water return pipe 22. The condenser 42 of the water source heat pump 4 heats up the return water of the second water return pipe 22 by heat exchange and then flows back to the second water supply pipe 21. The number of CO2 heat pumps and water source heat pumps 4 can be determined according to the actual heating scenario. The more the number, the more the resistance of the first network management 1 is reduced, and the lower the power consumption of the heat pump. In this embodiment, the CO2 heat pump is a water source CO2 heat pump.

[0028] By setting up the CO2 heat pump 5, the CO2 heat pump 5 can maintain high energy efficiency at a low evaporation temperature, and can also make the outlet water temperature reach above 80°C. It is directly connected to the first water supply pipe 11 for heating, and the heat storage device 3 is used to store hot water. The heat storage device 3 is set up, and the peak-valley electricity price difference is utilized. During the valley period, the heat pump runs at full load to store hot water in the heat storage device 3. During the peak period, the heat pump runs at low load or does not run, and the hot water in the heat storage device 3 is used for heating. This can minimize the power cost of the system operation and improve the economy of the system operation.

[0029] Further, if Figure 1 As shown, the water source heat pump 4 also includes a first compressor 43 and a first throttle valve 44. The first evaporator 41, the condenser 42, the first compressor 43 and the first throttle valve 44 are connected in sequence to form a first circulation loop. The water inlet of the first evaporator 41 is connected to the first water return pipe 12, the water outlet of the first evaporator 41 is connected to the CO2 heat pump 5, the water inlet of the condenser 42 is connected to the second water return pipe 22, and the water outlet of the condenser 42 is connected to the second water supply pipe 21. The cold water in the first water return pipe 12 enters the first evaporator 41 for heat exchange and cooling, and then enters the CO2 heat pump 5. The cold water flowing out of the second water return pipe 22 enters the condenser 42 for heat exchange, and the hot water after heat exchange flows into the second water supply pipe 21. Through the second water supply pipe 21, hot water is provided to the user 200.

[0030] Further, if Figure 1As shown, the CO2 heat pump 5 includes a second evaporator 51, a gas cooler 52, a second compressor 53 and a second throttle valve 54. The second evaporator 51, the gas cooler 52, the second compressor 53 and the second throttle valve 54 sequentially form a second circulation loop. The water inlet end of the second evaporator 51 is connected to the water outlet end of the first evaporator 41, and the water outlet end of the second evaporator 51 is connected to the low-temperature water inlet and outlet of the heat storage device 3. The water inlet end of the gas cooler 52 is connected to the water outlet end of the first evaporator 41, and the water outlet end of the gas cooler 52 is connected to the high-temperature water inlet and outlet of the heat storage device 3. In this embodiment, part of the cold water flowing out of the first evaporator 41 after heat exchange enters the second evaporator 51, and part enters the gas cooler 52. After the cold water flowing out of the first evaporator 41 is heat exchanged and cooled again in the second evaporator 51, it flows into the low-temperature water inlet and outlet of the heat storage device 3 or into the first return water pipe 12. After the cold water flowing out of the first evaporator 41 is heat exchanged and heated up in the gas cooler 52, it flows into the high-temperature water inlet and outlet of the heat storage device 3 or the first water supply pipe 11.

[0031] Further, if Figure 1 As shown, the large temperature difference heating system in the utility model further includes a first connecting pipe 6 and a second connecting pipe 7, one end of the first connecting pipe 6 is connected to the water outlet of the first evaporator 41, and the other end of the first connecting pipe 6 is connected to the water inlet of the second evaporator 51, one end of the second connecting pipe 7 is connected to the water outlet of the first evaporator 41, and the other end of the second connecting pipe 7 is connected to the water inlet of the gas cooler 52. The first connecting pipe 6 is provided with a second water pump 61 and a first switch valve 62, and the second connecting pipe 7 is provided with a third water pump 71 and a second switch valve 72. The flow rate of water entering the second evaporator 51 is controlled by providing the second water pump 61 and the first switch valve 62, and the flow rate of water entering the gas cooler 52 is controlled by providing the third water pump 71 and the second switch valve 72.

[0032] Further, if Figure 1 and Figure 2 As shown, the heat storage device 3 includes a water tank 31, the high-temperature water inlet and outlet of the heat storage device 3 are arranged at the top of the water tank 31, and the low-temperature water inlet and outlet of the heat storage device 3 are arranged at the bottom of the water tank 31. In this embodiment, the water tank 31 is a temperature-slope layer water tank 31. Compared with the conventional heating system hot water storage tank 31, the temperature difference between the hot water and the cold water in the temperature-slope layer water tank 31 is larger. Under the same heat storage capacity, the volume is smaller and the equipment investment is small. In other embodiments, the user 200 can set the size of the water tank 31 according to actual needs to meet the heating time for the first network management 1, and ensure that the water tank 31 can be used to heat the peak power period.

[0033] The CO2 heat pump 5 can maintain high energy efficiency at low evaporation temperatures, so that the outlet water temperature reaches above 80°C. The outlet end of the second evaporator 51 of the CO2 heat pump 5 is connected to the low-temperature water inlet and outlet of the heat storage device 3, and the outlet end of the gas cooler 52 is connected to the high-temperature water inlet and outlet of the heat storage device 3. The CO2 heat pump 5 delivers hot water to the high-temperature water inlet and outlet of the water tank 31, and delivers cold water to the low-temperature water inlet and outlet of the water tank 31, thereby increasing the internal temperature difference of the heat storage device 3 and increasing the performance of the water tank 31. Under the same heat storage capacity, the volume is small, the equipment investment is small, and the cost is saved. In addition, a heat storage device 3 is set up to utilize the peak-valley electricity price difference. During the valley period, the heat pump runs at full load to store hot water for the heat storage device 3. During the peak period, the heat pump runs at low load or does not run, and the hot water in the heat storage device 3 is used for heating, which can minimize the power cost of the system operation and improve the economy of the system operation.

[0034] Further, if Figure 2 As shown, the heat storage device 3 also includes a first water pipe 32, a second water pipe 33, a third water pipe 34, a fourth water pipe 35 and a fifth water pipe 36, one end of the first water pipe 32 is connected to the first water supply pipe 11, the other end of the first water pipe 32 is connected to the first return water pipe 12, one end of the second water pipe 33 is connected to the first pipe, the other end of the second water pipe 33 is connected to the high-temperature water inlet and outlet of the water tank 31, one end of the third water pipe 34 is connected to the first water pipe 32, the other end of the third water pipe 34 is connected to the low-temperature water inlet and outlet of the water tank 31, one end of the fourth water pipe 35 is connected to the second water pipe 33, the other end of the fourth water pipe 35 is connected to the third water pipe 34, one end of the fifth water pipe 36 is connected to the first water pipe 32, and the other end of the fifth water pipe 36 is connected to the fourth water pipe 35.

[0035] Further, if Figure 2 As shown, the heat storage device 3 also includes a first valve 321, a second valve 331, a third valve 322, a fourth valve 351, a fifth valve 323, a sixth valve 352, a seventh valve 341, an eighth valve 324 and a first water pump 361. The first valve 321, the third valve 322, the fifth valve 323 and the eighth valve 324 are arranged on the first water pipe 32, the second valve 331 is arranged on the second water pipe 33, one end of the second water pipe 33 is connected between the first valve 321 and the third valve 322, the seventh valve 341 is arranged on the third water pipe 34, one end of the third water pipe 34 is connected between the fifth valve 323 and the eighth valve 324, the fourth valve 351 and the sixth valve 352 are arranged on the fourth water pipe 35, the first water pump 361 is arranged on the fifth water pipe 36, one end of the fifth water pipe 36 is arranged between the third valve 322 and the fifth valve 323, and the other end of the fifth water pipe 36 is arranged between the fourth valve 351 and the sixth valve 352.

[0036] When the heat storage device 3 is not working, the first valve 321 and the eighth valve 324 are opened, the second valve 331, the third valve 322, the fourth valve 351, the fifth valve 323, the sixth valve 352, the seventh valve 341, and the first water pump 361 are closed, and the hot water after heat exchange in the gas cooler 52 of the CO2 heat pump 5 flows directly into the first water supply pipe 11 through the first valve 321, and the cold water after heat exchange in the second evaporator 51 flows directly back to the first return water pipe 12 through the eighth valve 324.

[0037] During the off-peak period, the CO2 heat pump 5 stores hot water in the water tank 31, the second valve 331, the fifth valve 323, the sixth valve 352, the first water pump 361 and the eighth valve 324 are opened, and the first valve 321, the third valve 322, the fourth valve 351 and the seventh valve 341 are closed. The hot water after heat exchange in the gas cooler 52 enters the high-temperature water inlet and outlet of the water tank 31 through the pipeline, and the hot water continuously enters the water tank 31. At the same time, the cold water at the bottom of the water tank 31 flows out from the low-temperature water inlet and outlet of the water tank 31, and flows back to the first return water pipe 12 through the sixth valve 352, the first water pump 361, the fifth valve 323, and the eighth valve 324 in sequence. The cold water after heat exchange in the second evaporator 51 of the CO2 heat pump 5 flows back to the first return water pipe 12 through the eighth valve 324. In the process of storing hot water in the water tank 31 , the cold water flowing out from the water outlet of the water tank 31 circulates in the first water pump 361 . The first water pump 361 can stabilize the pressure difference of the water tank 31 and facilitate the cold water at the bottom of the water tank 31 to be pumped to the first return water pipe 12 .

[0038] During peak power periods, the heat storage device 3 is used to supply heat to the first network pipe 1, which can minimize the power cost of the system operation. The first valve 321, the third valve 322, the fourth valve 351, the first water pump 361 and the seventh valve 341 are opened, and the second valve 331, the fifth valve 323, the sixth valve 352 and the eighth valve 324 are closed. When supplying heat to the first network pipe 1, heat is supplied by the heat storage device 3 on the one hand, and by the CO2 heat pump 5 on the other hand. When supplying heat to the first network pipe 1 through the water tank 31, the hot water in the water tank 31 flows out from the high-temperature water inlet and outlet of the water tank 31, and flows into the first water supply pipe 11 through the fourth valve 351, the first water pump 361, the third valve 322 and the first valve 321 in sequence, so as to supply heat to the system. On the other hand, when the CO2 heat pump 5 supplies heat to the first network pipe 1, the hot water after heat exchange in the gas cooler 52 enters the first water supply pipe 11 through the first valve 321 for heat supply, and at the same time, the cold water after heat exchange in the second evaporator 51 flows to the low-temperature water inlet and outlet of the water tank 31 through the seventh valve 341, and cold water is continuously injected into the water tank 31. In the process of the water tank 31 releasing heat to the first network pipe 1, the hot water flowing out of the water inlet of the water tank 31 circulates in the first water pump 361. The first water pump 361 can stabilize the pressure difference of the water tank 31, so as to facilitate the pumping of the hot water in the water tank 31 to the first water supply pipe 11.

[0039] Further, if Figure 1 As shown, in order to control the mass flow rate at the water inlet of the second evaporator 51, the water temperature at the water outlet of the first evaporator 41 is T1, the mass flow rate entering the water inlet of the second evaporator 51 is Q1, the water temperature at the water outlet of the second evaporator 51 is T2, the mass flow rate entering the water inlet of the gas cooler 52 is Q2, the water temperature at the water outlet of the gas cooler 52 is T3, the energy efficiency coefficient of the CO2 heat pump is COP, the water flow rate entering the second evaporator 51 is controlled by controlling the first switch valve 62 and the second water pump 61, and the water flow rate entering the gas cooler 52 is controlled by controlling the second switch valve 72 and the third water pump 71. The mass flow rate at the water inlet of the second evaporator 51 can be controlled as needed, and the control formula is:

[0040]

[0041] Further, if Figure 1As shown, in order to realize the control of each pipeline of the system, a fourth water pump 111 and a third switch valve 112 are arranged on the first water supply pipe 11, and the flow rate and on-off of the water in the first water supply pipe 11 are controlled by arranging the fourth water pump 111 and the third switch valve 112. A fourth switch valve 121 is arranged on the first water return pipe 12, and the on-off of the water in the first water return pipe 12 is controlled by arranging the fourth switch valve 121. A fifth switch valve 211 is arranged on the second water supply pipe 21, and the on-off of the water in the second water return pipe 22 is controlled by arranging the fifth switch valve 211. The second water supply pipe 21 is provided with a fifth switch valve 211, and the on-off of the water in the second water return pipe 22 is controlled by arranging the fifth switch valve 211. A fifth water pump 221 is provided on the return water pipe 22, and the flow rate of water in the second return water pipe 22 is controlled by the fifth water pump 221. A sixth switch valve and a sixth water pump are provided between the water outlet end of the condenser 42 and the second water supply pipe 21, and the flow rate and on-off of water between the water outlet end of the condenser 42 and the second water supply pipe 21 are controlled by the sixth switch valve and the sixth water pump. A seventh switch valve is provided between the water inlet end of the condenser 42 and the second return water pipe 22, and the on-off of water between the water inlet end of the condenser 42 and the second return water pipe 22 is controlled by the seventh switch valve.

[0042] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all implementation methods here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A large temperature difference heating system, used for energy transmission between a heat source plant and a user, characterized in that: It includes a first heat exchange station and a second heat exchange station arranged between a heat source plant and a user, a first network pipe is arranged between the first heat exchange station and the second heat exchange station, a second network pipe is arranged between the second heat exchange station and the user, the first network pipe includes a first water supply pipe and a first water return pipe, the second network pipe includes a second water supply pipe and a second water return pipe, a heat storage device, a CO2 heat pump and a first evaporator of a water source heat pump are connected in sequence between the first water supply pipe and the first water return pipe, the first evaporator of the water source heat pump cools the return water in the first return pipe by heat exchange and then flows back to the CO2 heat pump, the CO2 heat pump exchanges the water and then flows to the heat storage device, the second water supply pipe and the second return pipe are connected to the condenser of the water source heat pump, the condenser of the water source heat pump heats up the return water in the second return pipe by heat exchange and then flows back to the second water supply pipe.

2. The large temperature difference heating system according to claim 1, characterized in that: The water source heat pump also includes a first compressor and a first throttle valve. The first evaporator, the condenser, the first compressor and the first throttle valve are connected in sequence to form a first circulation loop. The water inlet of the first evaporator is connected to the first return pipe, the water outlet of the first evaporator is connected to the CO2 heat pump, the water inlet of the condenser is connected to the second return pipe, and the water outlet of the condenser is connected to the second water supply pipe.

3. The large temperature difference heating system according to claim 2, characterized in that: The CO2 heat pump includes a second evaporator, a gas cooler, a second compressor and a second throttle valve, which sequentially form a second circulation loop. The water inlet of the second evaporator is connected to the water outlet of the first evaporator, and the water outlet of the second evaporator is connected to the low-temperature water inlet and outlet of the heat storage device. The water inlet of the gas cooler is connected to the water outlet of the first evaporator, and the water outlet of the gas cooler is connected to the high-temperature water inlet and outlet of the heat storage device.

4. The large temperature difference heating system according to claim 1, characterized in that: The heat storage device comprises a water tank, the high-temperature water inlet and outlet of the heat storage device are arranged at the top of the water tank, and the low-temperature water inlet and outlet of the heat storage device are arranged at the bottom of the water tank.

5. The large temperature difference heating system according to claim 4, characterized in that: The heat storage device also includes a first water pipe, a second water pipe, a third water pipe, a fourth water pipe and a fifth water pipe, one end of the first water pipe is connected to the first water supply pipe, the other end of the first water pipe is connected to the first water return pipe, one end of the second water pipe is connected to the first water pipe, the other end of the second water pipe is connected to the high-temperature water inlet and outlet of the water tank, one end of the third water pipe is connected to the first water pipe, the other end of the third water pipe is connected to the low-temperature water inlet and outlet of the water tank, one end of the fourth water pipe is connected to the second water pipe, the other end of the fourth water pipe is connected to the third water pipe, one end of the fifth water pipe is connected to the first water pipe, and the other end of the fifth water pipe is connected to the fourth water pipe.

6. The large temperature difference heating system according to claim 5, characterized in that: The heat storage device also includes a first valve, a second valve, a third valve, a fourth valve, a fifth valve, a sixth valve, a seventh valve, an eighth valve and a first water pump. The first valve, the third valve, the fifth valve and the eighth valve are arranged on the first water pipe, the second valve is arranged on the second water pipe, one end of the second water pipe is connected between the first valve and the third valve, the seventh valve is arranged on the third water pipe, one end of the third water pipe is connected between the fifth valve and the eighth valve, the fourth valve and the sixth valve are arranged on the fourth water pipe, the first water pump is arranged on the fifth water pipe, one end of the fifth water pipe is arranged between the third valve and the fifth valve, and the other end of the fifth water pipe is arranged between the fourth valve and the sixth valve.

7. The large temperature difference heating system according to claim 3, characterized in that: It also includes a first connecting pipe and a second connecting pipe, one end of the first connecting pipe is connected to the water outlet of the first evaporator, and the other end of the first connecting pipe is connected to the water inlet of the second evaporator, one end of the second connecting pipe is connected to the water outlet of the first evaporator, and the other end of the second connecting pipe is connected to the water inlet of the gas cooler.

8. The large temperature difference heating system according to claim 7, characterized in that: The first connecting pipe is provided with a second water pump and a first switch valve, and the second connecting pipe is provided with a third water pump and a second switch valve.

9. The large temperature difference heating system according to claim 8, characterized in that: The water temperature at the outlet of the first evaporator is T1, the mass flow rate of the water inlet of the second evaporator is Q1, the water temperature at the outlet of the second evaporator is T2, the mass flow rate of the water inlet of the gas cooler is Q2, the water temperature at the outlet of the gas cooler is T3, the energy efficiency coefficient of the CO2 heat pump is COP, the water flow rate of the second evaporator is controlled by controlling the first switch valve and the second water pump, and the water flow rate of the gas cooler is controlled by controlling the second switch valve and the third water pump. The control formula is:

10. The large temperature difference heating system according to claim 1, characterized in that: A fourth water pump and a third switch valve are provided on the first water supply pipe, a fourth switch valve is provided on the first water return pipe, a fifth switch valve is provided on the second water supply pipe, a fifth water pump is provided on the second water return pipe, a sixth switch valve and a sixth water pump are provided between the water outlet of the condenser and the second water supply pipe, and a seventh switch valve is provided between the water inlet of the condenser and the second water return pipe.

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