Large-temperature-difference central heating system with coupling complementation of vapor compression type heat pump and absorption type heat pump

Abstract

The utility model discloses a large-temperature-difference central heating system with coupling complementation of a steam compression type heat pump and an absorption type heat pump. The large-temperature-difference central heating system is characterized by comprising a primary hot water pipe network, a secondary hot water pipe network, an absorption type heat pump unit, a first water source heat pump unit, a second water source heat pump unit, a heat storage water tank, a thermal power plant, a photovoltaic power generation and wind generating set and a user. The primary hot water pipe network comprises a primary water supply pipeline and a primary water return pipeline, and the secondary hot water pipe network comprises a secondary water supply pipeline and a secondary water return pipeline; the absorption heat pump unit, the first water source heat pump unit and the second water source heat pump unit are sequentially connected into a primary hot water pipe network in series, and heat is taken from the primary hot water pipe network. The absorption heat pump unit, the first water source heat pump unit and the second water source heat pump unit are connected into a secondary hot water pipe network in parallel, and heat is released to the secondary hot water pipe network and supplied to users; power generated by the thermal power plant is used for driving the first water source heat pump unit. The photovoltaic power generation and wind generating set is used for generating power to drive the second water source heat pump unit.

Description

Technical Field

[0001] The utility model belongs to the field of urban centralized heating systems, and in particular relates to a multi-heat pump complementary large temperature difference centralized heating system for balancing urban heat and power grids. Background Art

[0002] Since thermal power plants use the principle of determining electricity based on heat, that is, they generate electricity on the premise of meeting heating demand, this often results in the peak electricity produced by thermal power plants exceeding the user's consumption capacity when the heating load reaches its maximum, resulting in a mismatch between the supply and demand of urban heat and power grids. In addition, with the addition of renewable energy sources such as solar energy and wind energy, when the thermal power plant's power generation is in excess, these renewable energy equipment have to stop operating, resulting in serious wind, solar and electricity abandonment in winter. Considering the current high cost of batteries, it is not realistic to store excess power generation through cross-seasonal power storage.

[0003] On the other hand, in order to reduce the transmission energy consumption of the primary network of the urban centralized heating system and improve the utilization efficiency of the exhaust steam of the thermal power plant, hot water absorption heat pumps are currently used in the heat exchange station for large temperature difference heat exchange. The return water temperature of the 110-120℃ primary network water supply from the thermal power plant can reach 30-35℃ after the absorption heat pump takes heat. There is still abundant waste heat resources in the return water that have not been fully utilized, and there is room for further improvement in the large temperature difference heat exchange of the centralized heating network. Utility Model Content

[0004] In view of the defects of the prior art, the purpose of the utility model is to provide a large temperature difference centralized heating system in which an electric-driven steam compression heat pump assists an absorption heat pump for supplementary heating. In this system, the electric heat pump is driven by the peak electricity of the cogeneration of heat and power in coordination with wind power generation and solar photovoltaic power generation, and the surplus electricity is stored in the form of thermal energy. On the secondary network side of the heat exchange station, by connecting a hot water storage tank, an electric-driven steam compression heat pump and an absorption heat pump in parallel, the system can realize the functions of heat storage by the hot water storage tank, and joint heating by the hot water storage tank / electrically driven steam compression heat pump and absorption heat pump. This system can not only balance the supply and demand relationship between the urban power grid and the heating network in winter, but also improve the exhaust steam utilization efficiency of the thermal power plant and the transmission and distribution capacity of the heating network by lowering the return water temperature of the primary network and widening the supply and return water temperature difference of the primary network.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] A large temperature difference centralized heating system with steam compression and absorption heat pump coupling complementation, characterized in that it is composed of a primary hot water pipe network, a secondary hot water pipe network, an absorption heat pump unit, a first water source heat pump unit, a second water source heat pump unit, a hot water storage tank, a thermal power plant, a photovoltaic power generation and wind power generator unit, and a user. The primary hot water pipe network includes a primary water supply pipe and a primary return pipe; the secondary hot water pipe network includes a secondary water supply pipe and a secondary return pipe; further, the absorption heat pump unit and the first water source heat pump unit and the second water source heat pump unit are connected in series to the primary hot water pipe network in sequence, and heat is taken from the primary hot water pipe network. The absorption heat pump unit and the first water source heat pump unit and the second water source heat pump unit are connected in parallel to the secondary hot water pipe network, and heat is released to the secondary hot water pipe network for supply to users. Further, the thermal power plant drives the first water source heat pump unit by electricity; the photovoltaic power generation and wind power generator unit drives the second water source heat pump unit by electricity.

[0007] The absorption heat pump unit includes an absorption heat pump evaporator, an absorption heat pump condenser, a generator, an absorber, a refrigerant pump, a solution pump, a solution heat exchanger, and an absorption heat pump throttle valve. Specifically, the absorption heat pump evaporator, the absorption heat pump condenser, the absorption heat pump throttle valve, the generator, the solution heat exchanger, and the absorber are connected through pipelines to form an absorption heat pump refrigerant loop and an absorbent loop. The inlet of the generator is connected to the primary water supply pipeline through a pipeline, the outlet of the generator is connected to the inlet of the absorption heat pump evaporator through a pipeline, and the outlet of the absorption heat pump evaporator is connected to the first water source heat pump evaporator through a pipeline; the inlet of the absorber is connected to the secondary return water pipeline through a pipeline, the outlet of the absorber is connected to the inlet of the absorption heat pump condenser through a pipeline, and the outlet of the absorption heat pump condenser is connected to the secondary water supply pipeline through a pipeline.

[0008] The first water source heat pump unit includes a first water source heat pump evaporator, a first water source heat pump condenser, a first water source heat pump compressor, and a first water source heat pump throttle valve. Specifically, the first water source heat pump evaporator, the first water source heat pump condenser, the first water source heat pump compressor, and the first water source heat pump throttle valve form a first water source heat pump refrigerant loop through a pipeline. The inlet of the first water source heat pump evaporator is connected to the outlet of the absorption heat pump evaporator through a pipeline, and the outlet of the first water source heat pump evaporator is connected to the second water source heat pump evaporator through a pipeline; the inlet of the first water source heat pump condenser is connected to the secondary return water pipeline through a pipeline, and the outlet of the first water source heat pump condenser is connected to the secondary water supply pipeline through a pipeline; the first water source heat pump compressor is connected to the thermal power plant generator set through a circuit.

[0009] The second water source heat pump unit includes a second water source heat pump evaporator, a hot water storage tank, a second water source heat pump compressor, and a second water source heat pump throttle valve. Specifically, the second water source heat pump evaporator, the hot water storage tank, the second water source heat pump compressor, and the second water source heat pump throttle valve constitute a second water source heat pump refrigerant loop. The inlet of the second water source heat pump evaporator is connected to the outlet of the first water source heat pump evaporator through a pipeline, and the outlet of the second water source heat pump evaporator is connected to the primary return water pipeline through a pipeline; the inlet of the hot water storage tank is connected to the secondary return water pipeline through a pipeline, and the outlet of the hot water storage tank is connected to the secondary water supply pipeline through a pipeline; the second water source heat pump compressor is connected to the photovoltaic power generation and wind power generation group through a circuit.

[0010] The utility model adopts the above technical scheme, and has at least the following beneficial effects: 1. The utility model adopts the complementary coupling form of steam compression and absorption heat pumps, and the water source heat pump or the hot water storage tank cooperates with the absorption heat pump to perform peak load regulation under high heating load conditions; therefore, compared with the conventional heat exchange station in which only the absorption heat pump operates, the utility model can reduce the equipment capacity when selecting the unit, thereby reducing the initial investment of the system. 2. The utility model uses electricity from the first water source heat pump unit from the cogeneration of the thermal power plant, and the electricity used by the second water source heat pump comes from renewable energy such as solar energy and wind energy; therefore, the utility model can not only absorb the peak electricity generated when the thermal power plant is running at full load in winter, but also increase the utilization rate of renewable energy, thereby reducing the occurrence of wind, solar and electricity abandonment in winter, and making the urban power grid more stable. 3. The utility model connects the first water source heat pump unit and the second water source heat pump unit in parallel on the secondary network side, and through the opening and closing of the pipeline valve, it can realize the functions of heat storage in the hot water storage tank, and joint heating of the hot water storage tank / first water source heat pump and absorption heat pump, making the urban heating network more stable. 4. Since the utility model adopts the complementary form of steam compression and absorption heat pump coupling, the primary network water supply releases heat and cools down to the generator and evaporator of the absorption heat pump, and then enters the evaporator in the first and second water source heat pump units in turn for further heat release and cooling; therefore, the utility model widens the temperature difference between the primary network supply and return water, thereby improving the heat exchange efficiency on the heat source side of the thermal power plant and making full use of the waste heat resources of the primary network return water. 5. Since the utility model uses the method of heat storage in the hot water storage tank to convert surplus electrical energy into thermal energy, it not only improves the fluctuation of urban heat and power grids and ensures the safety and stability of the network, but also has better economic performance compared to battery storage. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a large temperature difference central heating system diagram that is a combination of steam compression and absorption heat pumps coupled and complementary;

[0012] FIG2(a) is a flow chart of the combined heating of the first water source heat pump unit and the absorption heat pump unit when renewable energy generation is scarce and thermal power plants have surplus electricity;

[0013] FIG2( b ) is a flow chart showing that when renewable energy generation is scarce and thermal power plants have surplus electricity, the absorption heat pump unit supplies heat to users and the first water source heat pump unit stores heat in the hot water storage tank;

[0014] Figure 3 This is a flow chart of a large temperature difference central heating system using a steam compression and absorption heat pump coupled and complementary system for use in areas where renewable energy generation is sufficient and thermal power plants have surplus electricity.

[0015] Figure 4 It is a flow chart of a large temperature difference central heating system in which a steam compression type and an absorption heat pump are coupled and complemented and applied to a hot water storage tank for heating.

[0016] Figure numerals: 1, generator; 2, solution heat exchanger; 3, solution pump; 4, absorber; 5, absorption heat pump condenser; 6, absorption heat pump throttle valve; 7, refrigerant pump; 8, absorption heat pump evaporator; 9, electric bypass valve; 10, first water source heat pump evaporator; 11, first heat source heat pump throttle valve; 12, first water source heat pump condenser; 13, electric regulating valve; 14, first water source heat pump compressor; 15, electric bypass valve; 16, second Water source heat pump evaporator; 17. Second water source heat pump throttle valve; 18. Heat storage tank; 19. Second water source heat pump compressor; 20. Renewable energy circuit; 21. Photovoltaic generator set; 22. Wind generator set; 23. Electric regulating valve; 24. Electric regulating valve; 25. Secondary return water pipeline; 26. Secondary water supply pipeline; 27. User; 28. Thermal power plant circuit; 29. ​​Primary return water pipeline; 30. Primary water supply pipeline; 31. Thermal power plant. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in combination with specific examples and with reference to the accompanying drawings.

[0018] like Figure 1As shown, the utility model includes a generator 1, a solution heat exchanger 2, a solution pump 3, an absorber 4, an absorption heat pump condenser 5, an absorption heat pump throttle valve 6, a refrigerant pump 7, an absorption heat pump evaporator 8, an electric bypass valve 9, a first water source heat pump evaporator 10, a first heat source heat pump throttle valve 11, a first water source heat pump condenser 12, an electric regulating valve 13, a first water source heat pump compressor 14, an electric bypass valve 15, a second water source heat pump evaporator 16, a second water source heat pump throttle valve 17, a hot water storage tank 18, a second water source heat pump compressor 19, a renewable energy circuit 20, a photovoltaic generator set 21, a wind generator set 22, an electric regulating valve 23, an electric regulating valve 24, a secondary return water pipeline 25, a secondary water supply pipeline 26, a user 27, a thermal power plant circuit 28, a primary return water pipeline 29, a primary water supply pipeline 30, and a thermal power plant 31.

[0019] In order to balance the urban heating network and the power grid, improve the utilization rate of renewable energy such as solar energy and wind energy, and flexibly meet the heating needs of urban users, the system involved in the utility model can be divided into three operating conditions according to the thermal power plant and renewable energy power generation:

[0020] Working condition 1: When renewable energy generation is scarce and thermal power plants have surplus electricity, the working principle is: turn on the first water source heat pump unit and the absorption heat pump unit, and turn off the second water source heat pump unit. Further, working condition 1 can be divided into two situations: the first water source heat pump unit and the absorption heat pump unit jointly provide heat, or the absorption heat pump unit provides heat to users and the first water source heat pump unit stores heat in the hot water storage tank.

[0021] The operation flow of the combined heating of the first water source heat pump unit and the absorption heat pump unit is shown in Figure 2 (a), the electric bypass valve 9 and the electric regulating valve 23 are closed, and the electric regulating valve 13, the electric bypass valve 15 and the electric regulating valve 24 are opened. Further, the system operation flow includes a primary network side flow cycle, a secondary network side flow cycle, an absorption heat pump unit flow cycle, a first water source heat pump unit flow cycle and a thermal power plant circuit cycle.

[0022] In the primary network-side flow cycle, the high-temperature hot water produced by the thermal power plant 31 flows into the generator 1 through the primary water supply pipe 30, and after releasing heat for the first time in the generator 1, it flows into the absorption heat pump evaporator 8 through the pipe for the second heat release, and then flows into the first water source heat pump evaporator 10 to complete the third heat release. After three heat exchanges and cooling, the hot water returns to the thermal power plant 31 through the primary return water pipe 29.

[0023] In the secondary network flow cycle, the return water from the user 27 is divided into two branches through the secondary return water pipe 25, one of which first flows into the absorber 4 to absorb the first heat, then flows into the absorption heat pump condenser 5 through the pipe to absorb the second heat, and then is sent to the user 27 through the secondary water supply pipe 26. The other branch flows into the first water source heat pump condenser 12 to absorb heat, and is also sent to the user 27 through the secondary water supply pipe 26.

[0024] In the flow cycle of the absorption heat pump unit, the dilute solution in the absorber 4 is transported by the solution pump 3, and enters the generator 1 after absorbing heat in the solution heat exchanger 2. After the dilute solution continues to absorb the heat of the primary water supply pipe 30 in the generator 1, the refrigerant in the solution vaporizes and escapes due to its low boiling point, and enters the absorption heat pump condenser 5 and is condensed by the secondary return water pipe 25. The refrigerant liquid after condensation and cooling flows into the absorption heat pump evaporator 8 through the absorption heat pump throttle valve 6, and is circulated by the refrigerant pump 7 to absorb heat and vaporize again from the primary water supply pipe 30. The generated refrigerant vapor escapes into the absorber 4 and is absorbed by the concentrated solution. On the other hand, due to the evaporation of the refrigerant, the dilute solution in the generator 1 becomes a concentrated solution, and after releasing heat in the solution heat exchanger 2, it flows back to the absorber 4. After absorbing the refrigerant vapor from the absorption heat pump evaporator 8, it becomes a dilute solution again. Thereby realizing the flow cycle of the absorption heat pump unit.

[0025] In the flow cycle of the first water source heat pump unit, the refrigerant in the first water source heat pump evaporator 10 absorbs heat from the primary water supply pipe 30 and evaporates into refrigerant vapor, which is then pressurized into high-temperature and high-pressure refrigerant vapor by the first water source heat pump compressor 14 and sent to the first water source heat pump condenser 12. The high-temperature and high-pressure refrigerant vapor releases heat to the secondary return water pipe 25 and condenses into refrigerant liquid, which flows back to the first water source heat pump evaporator 10 through the first water source heat pump throttle valve 11, completing the flow cycle of the first water source heat pump unit.

[0026] In the thermal power plant circuit cycle, the thermal power plant 31 transmits the cogeneration electricity to the first water source heat pump compressor 14 through the thermal power plant circuit 28 to drive the first water source heat pump unit.

[0027] The operation flow of the absorption heat pump unit supplying heat to the user and the first water source heat pump unit storing heat in the hot water storage tank is shown in Figure 2(b). The electric bypass valve 9 and the electric regulating valve 24 are closed, and the electric regulating valve 13, the electric bypass valve 15, and the electric regulating valve 23 are opened. Furthermore, the system operation flow includes a primary network side flow cycle, a secondary network side flow cycle, a heat storage cycle, an absorption heat pump unit flow cycle, a first water source heat pump unit flow cycle, and a thermal power plant circuit cycle.

[0028] The primary network side flow cycle, the absorption heat pump unit flow cycle, the first water source heat pump unit flow cycle, and the thermal power plant circuit cycle are the same as those described above.

[0029] In the secondary network side flow cycle, the return water from the user 27 is sent to the absorber 4 and the condenser 5 of the absorption heat pump in sequence through the secondary return water pipe 25 for heating, and then flows back to the user 27 through the secondary water supply pipe 26.

[0030] In the heat storage cycle, the hot water coming out of the first water source heat pump condenser 12 enters the hot water storage tank 18 to heat the water in the tank.

[0031] Working condition 2: When there is sufficient renewable energy generation and the thermal power plant has surplus electricity, the first water source heat pump unit, the second water source heat pump unit and the absorption heat pump unit are turned on at the same time. Renewable energy generation drives the second water source heat pump unit to store heat in the hot water storage tank; the thermal power plant generates electricity to drive the first water source heat pump unit, so that the first water source heat pump unit cooperates with the absorption heat pump unit to provide heat to users. At this time, the water flow on the primary network side can be appropriately reduced.

[0032] The operating process of this condition is as shown in the attached Figure 3 As shown, the electric bypass valve 9, the electric bypass valve 15, and the electric regulating valve 23 are closed, and the electric regulating valve 13 and the electric regulating valve 24 are opened. Further, the system operation process includes a primary network side flow cycle, a secondary network side flow cycle, an absorption heat pump unit flow cycle, a first water source heat pump unit flow cycle, a second water source heat pump unit flow cycle, a thermal power plant circuit cycle, and a renewable energy circuit cycle.

[0033] The primary network side flow cycle is different from the primary network side flow cycle in working condition 1 in that the hot water flowing out of the first water source heat pump evaporator 10 does not directly return to the primary return pipe 29, but is sent to the second water source heat pump evaporator 16 through the pipe to complete the fourth heat release and then flows back to the thermal power plant 31.

[0034] The secondary network side flow cycle, the absorption heat pump unit flow cycle, the first water source heat pump unit flow cycle, and the thermal power plant circuit cycle are the same as the operating condition 1 in which the first water source heat pump unit and the absorption heat pump unit jointly provide heating.

[0035] The flow cycle of the second water source heat pump unit is similar to the flow cycle of the first water source heat pump unit, except that the high-temperature and high-pressure refrigerant vapor pressurized by the second water source heat pump compressor 19 releases heat to the hot water storage tank 18 .

[0036] In the renewable energy circuit cycle, the photovoltaic generator set 21 and the wind generator set 22 supply the second water source heat pump compressor 19 through the renewable energy circuit 20 .

[0037] Working condition 3: When the heat storage tank is completed, the heat storage tank cooperates with the absorption heat pump to provide heat to meet the heating load demand. At this time, the water flow on the primary grid side can be appropriately reduced. Due to the instability of renewable energy power generation, the second water source heat pump unit cannot be directly used for secondary grid heating, and the heat storage tank is needed to maintain stable heating.

[0038] The operating process of this condition is as shown in the attached Figure 4 As shown, the electric regulating valve 23 and the electric regulating valve 24 are opened, and the other electric valves are adjusted accordingly according to the working conditions 1 and 2 according to the operating conditions of the unit.

[0039] In the secondary network side flow cycle, the return water from the user 27 flows out through the secondary return water pipe network 25 in at least two branches, one of which flows into the absorption heat pump unit to absorb heat from the absorber 4 and the condenser 5. The other branch flows into the hot water storage tank 18 of the second water source heat pump unit to absorb heat, and then is mixed with the previous branch through the pipeline and sent to the user 27 through the secondary water supply pipe network 26.

[0040] When selecting the circulating refrigerant for the first water source heat pump unit, the second water source heat pump unit and the absorption heat pump unit, the step-by-step heat utilization method must be followed.

[0041] The above embodiments are only used to illustrate the present invention, wherein the structures and connection modes of the components may be changed. Any equivalent transformations and improvements based on the technical solution of the present invention should not be excluded from the protection scope of the present invention.

Claims

1. A large temperature difference central heating system with steam compression and absorption heat pumps coupled and complementary, characterized in that: It includes a primary hot water pipe network, a secondary hot water pipe network, an absorption heat pump unit, a first water source heat pump unit, a second water source heat pump unit, a hot water storage tank, a thermal power plant, a photovoltaic power generation and wind power generation unit, and users; the primary hot water pipe network includes a primary water supply pipe and a primary return pipe; the secondary hot water pipe network includes a secondary water supply pipe and a secondary return pipe; the absorption heat pump unit and the first water source heat pump unit and the second water source heat pump unit are connected in series to the primary hot water pipe network in sequence, and take heat from the primary hot water pipe network; the absorption heat pump unit and the first water source heat pump unit and the second water source heat pump unit are connected in parallel to the secondary hot water pipe network, and release heat to the secondary hot water pipe network to supply users; the thermal power plant drives the first water source heat pump unit by electricity; the photovoltaic power generation and wind power generation unit drives the second water source heat pump unit by electricity; The absorption heat pump unit comprises an absorption heat pump evaporator, an absorption heat pump condenser, a generator, an absorber, a refrigerant pump, a solution pump, a solution heat exchanger, and an absorption heat pump throttle valve; the inlet of the generator is connected to the primary water supply pipeline through a pipeline, the outlet of the generator is connected to the inlet of the absorption heat pump evaporator through a pipeline, and the outlet of the absorption heat pump evaporator is connected to the first water source heat pump evaporator through a pipeline; the inlet of the absorber is connected to the secondary return water pipeline through a pipeline, the outlet of the absorber is connected to the inlet of the absorption heat pump condenser through a pipeline, and the outlet of the absorption heat pump condenser is connected to the secondary water supply pipeline through a pipeline; The first water source heat pump unit comprises a first water source heat pump evaporator, a first water source heat pump condenser, a first water source heat pump compressor, and a first water source heat pump throttle valve; the inlet of the first water source heat pump evaporator is connected to the outlet of the absorption heat pump evaporator through a pipeline, and the outlet of the first water source heat pump evaporator is connected to the second water source heat pump evaporator through a pipeline; the inlet of the first water source heat pump condenser is connected to the secondary water return pipeline through a pipeline, and the outlet of the first water source heat pump condenser is connected to the secondary water supply pipeline through a pipeline; the first water source heat pump compressor is connected to the thermal power plant generator set through a circuit; The second water source heat pump unit includes a second water source heat pump evaporator, a hot water storage tank, a second water source heat pump compressor, and a second water source heat pump throttle valve; the inlet of the second water source heat pump evaporator is connected to the outlet of the first water source heat pump evaporator through a pipeline, and the outlet of the second water source heat pump evaporator is connected to the primary return water pipeline through a pipeline; the inlet of the hot water storage tank is connected to the secondary return water pipeline through a pipeline, and the outlet of the hot water storage tank is connected to the secondary water supply pipeline through a pipeline; the second water source heat pump compressor is connected to the photovoltaic power generation and wind power generation group through a circuit.

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