Cascade energy utilization system, scheduling control method, device, equipment and medium

Abstract

The invention relates to the technical field of energy conversion, and discloses a cascade energy utilization system, a scheduling control method and device, equipment and a medium. The system comprises a photovoltaic power generation module, an electric heater, a hot molten salt tank, a cold molten salt tank, a steam generator, a primary heat exchanger, a secondary heat exchanger, a first water source heat pump unit, a second water source heat pump unit, a plurality of valves and a control module, wherein the valves comprise a first valve, a second valve, a third valve, a fourth valve, a fifth valve, a sixth valve and a seventh valve. The system provided by the invention aims at an energy system of a sewage treatment plant, high photovoltaic abandoned light, low efficiency of heat pumps, waste heat waste and island operation pain points, depends on photovoltaic energy, fused salt heat storage, a two-stage heat exchanger, double heat pumps and a dynamic control framework, stores photovoltaic energy by utilizing a fused salt heat storage system, preheats sewage through the two-stage heat exchanger, improves COP of the heat pumps, and reduces the energy consumption of the heat pumps. Waste heat is fully utilized, and dependence on a power grid is reduced.

Description

Technical Field

[0001] This invention relates to the field of energy conversion technology, specifically to cascade energy utilization systems, scheduling and control methods, devices, equipment, and media. Background Technology

[0002] Wastewater treatment plants are major energy consumers in cities, accounting for 1%-3% of total urban electricity consumption, and this figure continues to rise. Traditional operating models heavily rely on grid power and fossil fuel heating, facing both rising energy costs and conflicting with carbon neutrality goals. While current energy-saving technologies for wastewater treatment plants focus on photovoltaic power generation, wastewater source heat pumps, and molten salt thermal energy storage, they have significant drawbacks: photovoltaic power generation is affected by day / night cycles and weather, with an average curtailment rate exceeding 20%; wastewater source heat pumps generally have a coefficient of performance (COP) below 3.5 because wastewater is typically located in the low-temperature range of 10-25℃; and the 150-250℃ medium-temperature waste heat emitted by molten salt thermal energy storage systems is often directly discarded due to its mismatch with conventional needs, resulting in secondary energy waste.

[0003] Existing solutions for simply paralleling and integrating the above systems still suffer from systemic defects: photovoltaic, thermal storage, and heat pumps operate in isolation, resulting in inefficient energy flow. For example, the >300℃ high-temperature steam from molten salt thermal storage is only used for 80℃ hot water preparation, leading to a loss of over 40%; the inefficiency of wastewater source heat pumps remains unresolved, with a COP difficult to break 4.0; and there is a lack of effective energy transfer paths between the medium-temperature waste heat from molten salt and the low-temperature heat source from wastewater heat pumps, resulting in a long-term overall system energy efficiency below 45%. Therefore, there is an urgent need to innovate the energy synergy architecture, breaking down the quality barriers between photovoltaic power, molten salt thermal energy, and wastewater thermal energy to achieve multi-energy flow cascade conversion and deep synergy. Summary of the Invention

[0004] This invention provides a cascaded energy utilization system, scheduling and control method, device, equipment and medium to solve the problem of isolated operation and inefficient energy flow between photovoltaic, thermal storage and heat pump in related technologies.

[0005] In a first aspect, the present invention provides a cascaded energy utilization system, comprising: a photovoltaic power generation module, an electric heater, a hot molten salt tank, a cold molten salt tank, a steam generator, a primary heat exchanger, a secondary heat exchanger, a first water source heat pump unit, a second water source heat pump unit, multiple valves, and a control module. The multiple valves include a first valve, a second valve, a third valve, a fourth valve, a fifth valve, a sixth valve, and a seventh valve. The photovoltaic power generation module supplies power to the electric heater, the first water source heat pump unit, and the second water source heat pump unit. The outlet of the cold molten salt tank is connected to the inlet of the hot molten salt tank via the electric heater. The outlet of the hot molten salt tank is connected to the inlet of the steam generator. The outlet of the steam generator is connected to the cold molten salt tank via the first valve and to the inlet of the primary heat exchanger via the second valve. The primary heat exchanger... The first outlet of the primary heat exchanger is connected to the molten salt tank via the third valve, and is also connected to the first inlet of the secondary heat exchanger via the fourth valve. The second outlet of the primary heat exchanger is connected to the inlet of the first water source heat pump unit, and the target port of the primary heat exchanger is connected to the sewage tank via the fifth valve. The first outlet of the secondary heat exchanger is connected to the molten salt tank, and the second outlet of the secondary heat exchanger is connected to the second water source heat pump unit. The second water source heat pump unit is connected to the target port of the primary heat exchanger via the sixth valve and the fifth valve in sequence. The second inlet of the secondary heat exchanger is connected to the sewage tank via the seventh valve and the fifth valve in sequence. The control module is used to control the operating status of the electric heater, the primary heat exchanger, the secondary heat exchanger, the first water source heat pump unit, the second water source heat pump unit, and multiple valves according to the operating mode command.

[0006] The cascade energy utilization system provided by this invention addresses the pain points of existing wastewater treatment plant energy systems, such as high photovoltaic curtailment rates, low heat pump efficiency, severe waste of waste heat, and isolated system operation. It achieves a comprehensive breakthrough over existing technologies by relying on a collaborative architecture of photovoltaic power generation modules, molten salt thermal storage, a two-stage heat exchanger, dual water source heat pumps, and dynamic control. Firstly, the photovoltaic power generation modules prioritize power supply to the electric heaters and two water source heat pump units. Surplus electricity can drive the electric heaters to heat the low-temperature molten salt in the cold molten salt tank to a high temperature and store it in the hot molten salt tank, forming a stable storage buffer from electrical energy to thermal energy. During periods of low photovoltaic output, the hot molten salt tank releases heat to meet the needs of steam preparation and wastewater preheating, replacing grid power or fossil fuel heating and significantly reducing photovoltaic power waste. Secondly, the efficiency bottleneck is overcome by using a two-stage heat exchanger and molten salt waste heat preheating design. Molten salt from the steam generator outlet enters the first-stage heat exchanger via the second valve. The first-stage heat exchanger is also connected to the sewage tank via the fifth valve, allowing the waste heat from the molten salt to preheat the sewage. Simultaneously, the first outlet of the first-stage heat exchanger is connected to the second-stage heat exchanger via the fourth valve. The second-stage heat exchanger is connected to the sewage tank via the seventh valve, allowing the further cooled waste heat from the molten salt to preheat another stream of sewage. The preheated sewage then enters the first and second water source heat pump units, respectively, increasing the heat source temperature of the heat pumps and effectively improving the COP of the heat pumps. This solves the problem of low efficiency in existing heat pump technologies, enabling heat pumps to produce domestic hot water, heating hot water, or chilled water more efficiently. After passing through the steam generator, the molten salt does not entirely return to the cold molten salt tank via the first valve. Instead, it preferentially enters the primary heat exchanger via the second valve to release heat, and some molten salt further enters the secondary heat exchanger via the fourth valve to continue releasing heat. This utilizes all the medium-temperature waste heat that would otherwise be wasted in existing technologies for wastewater preheating, avoiding secondary energy waste and improving the energy efficiency of the molten salt thermal storage system. The control module can adjust the operating status of the electric heater, primary heat exchanger, secondary heat exchanger, and two heat pump units, as well as the opening and closing of various valves, according to the operating mode commands. This allows photovoltaic power generation, molten salt thermal storage, wastewater preheating, and heat pump operation to form a coherent energy flow chain, avoiding the extensive mode of high-quality but low-utilization, reducing energy losses, and thus improving the overall energy efficiency of the entire system. This addresses the long-standing issue of existing technologies having an overall energy efficiency of less than 45%. At the same time, the system's dependence on the power grid and fossil fuels is reduced, alleviating energy cost pressures and aligning with carbon neutrality goals.

[0007] In one optional implementation, the operating mode commands include heating mode commands, cooling mode commands, normal mode commands, and energy-saving mode commands. When the operating mode command is a heating mode command, the control module controls the first, third, and sixth valves to close, and the second, fourth, fifth, and seventh valves to open, controlling the electric heater, primary heat exchanger, secondary heat exchanger, and first water source heat pump unit to start operation, and controlling the second water source heat pump unit to operate in heating mode. When the operating mode command is a cooling mode command, the control module controls the first, fourth, and seventh valves to close, and the second, third, fifth, and seventh valves to open, controlling the electric heater, primary heat exchanger, secondary heat exchanger, and first water source heat pump unit to start operation, and controlling the second water source heat pump unit to operate in heating mode. When valve 6 is open, it controls the electric heater, primary heat exchanger, secondary heat exchanger, and first water source heat pump unit to start operation, and controls the second water source heat pump unit to operate in cooling mode; when the operating mode command is the normal mode command, it controls valves 2, 3, and 5 to open, and valves 1, 4, 6, and 7 to close, controlling the electric heater, primary heat exchanger, and first water source heat pump unit to start operation, and controlling the secondary heat exchanger and second water source heat pump unit to be in a shutdown state; when the operating mode command is the energy-saving mode command, it controls valve 1 to open, and valves 2, 3, 4, 5, 6, and 7 to close.

[0008] Secondly, the present invention provides a scheduling and control method for cascade energy utilization, used in the cascade energy utilization system of the first aspect or its corresponding embodiment described above. The method includes: acquiring an operating mode instruction; determining a control instruction based on the operating mode instruction; and controlling the operating status of an electric heater, a primary heat exchanger, a secondary heat exchanger, a first water source heat pump unit, a second water source heat pump unit, and multiple valves based on the control instruction.

[0009] This invention provides a scheduling and control method for cascaded energy utilization. Based on the operating mode command, it adjusts the working status of electric heaters, primary heat exchangers, secondary heat exchangers, two heat pump units, and the opening and closing of various valves, so that photovoltaic power generation, molten salt thermal storage, sewage preheating, and heat pump operation form a coherent energy flow chain. This avoids the extensive mode of high-quality energy being underutilized, reduces energy losses, and thus improves the overall energy efficiency of the entire system, improving the current situation where the overall energy efficiency of existing technologies has long been below 45%. At the same time, the system's dependence on the power grid and fossil fuels is reduced, which not only alleviates the pressure of energy costs but also aligns with the goal of carbon neutrality.

[0010] In one optional implementation, the method includes: when the cascade energy utilization system is detected to be operating in heating mode, acquiring the first real-time photovoltaic power output, first real-time wastewater temperature, first process load power, first photovoltaic power output prediction data, and first heat load prediction data of the cascade energy utilization system; using the first real-time photovoltaic power output, first real-time wastewater temperature, first process load power, first photovoltaic power output prediction data, and first heat load prediction data of the cascade energy utilization system to solve a pre-constructed optimization scheduling model to obtain the first molten salt electric heating power, the first power of the first water source heat pump unit, the first power of the second water source heat pump unit, the wastewater preheating heat of the first stage heat exchanger, and the wastewater preheating heat of the first and second stage heat exchangers. The optimization scheduling model includes an objective function. The first constraint under the number and heating mode is that the objective function is constructed with the goal of minimizing the function value. The function value is obtained by summing the economic term index, the energy storage balance term index, and the energy efficiency tracking term index. The economic term index is determined by the power of molten salt electric heating, the power of the first water source heat pump unit and the second water source heat pump unit. The energy storage balance term index is determined by the power of molten salt electric heating. The energy efficiency tracking term index is calculated by the wastewater preheating heat of the first heat exchanger and the wastewater preheating heat of the second heat exchanger. The cascade energy utilization system is scheduled by the power of the first molten salt electric heating, the first power of the first water source heat pump unit, the first power of the second water source heat pump unit, the wastewater preheating heat of the first and second heat exchangers.

[0011] In an optional implementation, the method further includes: when the cascade energy utilization system is detected to be operating in cooling mode, acquiring the second real-time photovoltaic power output, second real-time wastewater temperature, second process load power, second photovoltaic power output prediction data, and second heat load prediction data of the cascade energy utilization system; using the second real-time photovoltaic power output, second real-time wastewater temperature, second process load power, second photovoltaic power output prediction data, and second heat load prediction data of the cascade energy utilization system to solve a pre-constructed optimization scheduling model to obtain the second molten salt electric heating power, the second power of the first water source heat pump unit, the second power of the second water source heat pump unit, and the wastewater preheating heat of the second stage heat exchanger, thereby optimizing the scheduling. The model includes an objective function and a second constraint under the cooling mode. The objective function is constructed with the goal of minimizing the function value, which is obtained by summing the economic, energy storage balance, and energy efficiency tracking indicators. The economic indicators are determined by the molten salt electric heating power and the heat pump compressor power. The energy storage balance indicator is determined by the molten salt electric heating power. The energy efficiency tracking indicator is calculated by the wastewater preheating heat of the first-stage heat exchanger and the wastewater preheating heat of the second-stage heat exchanger. The cascade energy utilization system is scheduled using the second molten salt electric heating power, the second power of the first water source heat pump unit, the second power of the second water source heat pump unit, and the wastewater preheating heat of the second-stage heat exchanger.

[0012] In one alternative implementation, the objective function is:

[0013] in, Indicates the first Each period, This indicates the total number of time periods in the optimization cycle. express Electricity price during the specified time period express Power purchased by the grid during a given time period This represents the energy storage balance weighting coefficient. express The charged state of the molten salt during the time period, This represents the weighting factor for energy efficiency tracking. express The coefficient of performance (COP) of a time-limited heat pump in actual operation. This represents the optimal performance coefficient of the heat pump during actual operation.

[0014] Thirdly, the present invention provides a scheduling and control device for cascade energy utilization, used to execute the scheduling and control method for cascade energy utilization described in the second aspect above. The device includes: a first acquisition unit for acquiring an operating mode instruction; a determination unit for determining a control instruction based on the operating mode instruction; and a control unit for controlling the operating status of an electric heater, a primary heat exchanger, a secondary heat exchanger, a first water source heat pump unit, a second water source heat pump unit, and multiple valves based on the control instruction.

[0015] Fourthly, the present invention provides an electronic device, comprising: a memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the computer instructions to perform the scheduling and control method for cascade energy utilization described in the first aspect or any corresponding embodiment thereof.

[0016] Fifthly, the present invention provides a computer-readable storage medium storing computer instructions for causing a computer to execute the scheduling and control method for cascade energy utilization described in the first aspect or any corresponding embodiment thereof.

[0017] In a sixth aspect, the present invention provides a computer program product, including computer instructions for causing a computer to execute the scheduling and control method for cascade energy utilization described in the first aspect or any corresponding embodiment thereof. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of a cascade energy utilization system according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the first type of scheduling and control method for cascade energy utilization according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the second process of the scheduling and control method for cascade energy utilization according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the third process of the scheduling and control method for cascade energy utilization according to an embodiment of the present invention; Figure 5 This is a structural block diagram of a scheduling and control device for cascade energy utilization according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the hardware structure of an electronic device according to an embodiment of the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] It is understood that before using the technical solutions disclosed in the various embodiments of the present invention, users should be informed of the types, scope of use, and usage scenarios of the personal information involved in the present invention and their authorization should be obtained in accordance with relevant laws and regulations through appropriate means.

[0022] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0023] While energy-saving technologies for wastewater treatment plants revolve around photovoltaic power generation, wastewater source heat pumps, and molten salt thermal energy storage, they suffer from significant drawbacks: photovoltaic power generation is affected by day / night cycles and weather, with an average curtailment rate exceeding 20%; wastewater source heat pumps generally have a coefficient of performance (COP) below 3.5 because wastewater is typically located in the low-temperature range of 10-25℃; and the 150-250℃ medium-temperature waste heat emitted by molten salt thermal energy storage systems is often directly discarded due to its mismatch with conventional needs, resulting in secondary energy waste. Existing simple parallel integration schemes of the above systems still have systemic defects: photovoltaic, thermal energy storage, and heat pumps operate in isolation, resulting in inefficient energy flow. For example, the >300℃ high-temperature steam from molten salt thermal energy storage is only used for 80℃ hot water preparation, resulting in a loss of over 40%; the inefficiency of wastewater source heat pumps remains unresolved, making it difficult to achieve a COP below 4.0; and there is a lack of effective energy transfer paths between the medium-temperature waste heat from molten salt and the low-temperature heat source of the wastewater heat pump, resulting in a long-term overall system efficiency below 45%. Therefore, it is urgent to innovate the energy synergy architecture, break down the quality barriers of photovoltaic power, molten salt thermal energy, and sewage thermal energy, and achieve multi-energy flow cascade conversion and deep synergy.

[0024] In view of this, embodiments of this application provide a cascade energy utilization system, such as... Figure 1 As shown, the system includes: a photovoltaic power generation module 1, an electric heater 2, a hot molten salt tank 3, a cold molten salt tank 4, a steam generator 5, a primary heat exchanger 6, a secondary heat exchanger 7, a first water source heat pump unit 8, a second water source heat pump unit 9, multiple valves, and a control module 10. The multiple valves include a first valve 11, a second valve 12, a third valve 13, a fourth valve 14, a fifth valve 15, a sixth valve 16, and a seventh valve 17. Photovoltaic power generation module 1 supplies power to electric heater 2, first water source heat pump unit 8, and second water source heat pump unit 9; the outlet of cold molten salt tank 4 is connected to the inlet of hot molten salt tank 3 via electric heater 2; the outlet of hot molten salt tank 3 is connected to the inlet of steam generator 5; the outlet of steam generator 5 is connected to cold molten salt tank 4 via first valve 11 and to the inlet of primary heat exchanger 6 via second valve 12; the first outlet of primary heat exchanger 6 is connected to cold molten salt tank 4 via third valve 13, and the first outlet is also connected to the first inlet of secondary heat exchanger 7 via fourth valve 14; the second outlet of primary heat exchanger 6 is connected to the inlet of first water source heat pump unit 8, and the first outlet of primary heat exchanger 7 is connected to the inlet of second water source heat pump unit 8. The target port of the heater 6 is connected to the sewage tank 18 via the fifth valve 15; the first outlet of the secondary heat exchanger 7 is connected to the cold molten salt tank 4, and the second outlet of the secondary heat exchanger 7 is connected to the second water source heat pump unit 9; the second water source heat pump unit 9 is connected to the target port of the primary heat exchanger 6 via the sixth valve 16 and the fifth valve 15 in sequence; the second inlet of the secondary heat exchanger 7 is connected to the sewage tank 18 via the seventh valve 17 and the fifth valve 15 in sequence; the control module 10 is used to control the working status of the electric heater 2, the primary heat exchanger 6, the secondary heat exchanger 7, the first water source heat pump unit 8, the second water source heat pump unit 9, and multiple valves according to the operating mode command.

[0025] The operating mode commands include heating mode commands, cooling mode commands, normal mode commands, and energy-saving mode commands; When the operating mode command is the heating mode command, the control module 10 controls the first valve 11, the third valve 13 and the sixth valve 16 to close, the second valve 12, the fourth valve 14, the fifth valve 15 and the seventh valve 17 to open, controls the electric heater 2, the primary heat exchanger 6, the secondary heat exchanger 7 and the first water source heat pump unit 8 to start operation, and controls the second water source heat pump unit 9 to operate in the heating mode.

[0026] For example, the heating mode command is used to control the cascade energy utilization system to operate in heating mode. In this embodiment, the cascade energy utilization system is controlled to operate in heating mode during periods of low ambient temperature, such as winter. In heating mode, the electrical energy of the photovoltaic power generation module 1 is preferentially supplied to process loads such as water pumps and fans in the plant area through the power distribution center 19. The remaining electrical energy is divided into two paths: one part drives the electric heater 2 to heat the molten salt in the cold molten salt tank to a high temperature (e.g., 565°C) for storage; the other part drives the heat pump compressor. The high-temperature molten salt flows through the steam generator 5 (heat exchange system) to release steam >300°C for high-grade heat demand in processes such as sludge drying. The cooled molten salt (e.g., 200°C) enters the first-stage heat exchanger 6 to preheat a portion of the sewage (e.g., from 10-20°C to approximately 40°C). The sewage then enters the first water source heat pump unit 8 to produce domestic hot water (>60°C) that meets the demand for medium- and low-grade heat. The molten salt, after being further cooled (e.g., 140℃), enters the secondary heat exchanger 7 to preheat another part of the wastewater. The residual heat from the low-temperature molten salt raises the temperature of the wastewater (e.g., from 10-20℃ to approximately 30-35℃). The preheated wastewater is then pumped into the second water source heat pump unit 9 to produce the above-mentioned heating hot water (45-60℃) to meet the low-grade heat demand of the plant area. The wastewater then enters the subsequent treatment process.

[0027] Specifically, in heating mode, the pre-treated wastewater from the factory is split into two streams: one stream is used for domestic hot water production, and the other stream is used for heating hot water production. An example of calculating the COP (Coefficient of Performance) of heat pump heating is as follows: The waste heat from the molten salt at 200℃ first enters the primary heat exchanger, preheating the wastewater from 10℃ to 40℃. The molten salt, cooled to 140℃, then enters the preheater, preheating the wastewater from 10℃ to 35℃. The preheated wastewater then enters the heat pump evaporator, where the working fluid absorbs heat and evaporates. After being heated by the compressor, it outputs 60℃ hot water in the condenser. The heat pump COP enhancement model is shown in the following equation:

[0028] in, COP The coefficient of performance (COP) is a core indicator for measuring the energy conversion efficiency of heat pump units. This indicates the evaporation temperature of the heat pump. This indicates the temperature of the wastewater. When ΔT = 25℃, (66% higher than before preheating).

[0029] When the operating mode command is the cooling mode command, the control module 10 controls the first valve 11, the fourth valve 14, and the seventh valve 17 to close, the second valve 12, the third valve 13, the fifth valve 15, and the sixth valve 16 to open, controls the electric heater 2, the primary heat exchanger 6, the secondary heat exchanger 7, and the first water source heat pump unit 8 to start operation, and controls the second water source heat pump unit 9 to operate in cooling mode.

[0030] For example, the cooling mode command is used to control the cascade energy utilization system to operate in cooling mode. In this embodiment, the cascade energy utilization system is controlled to operate in cooling mode during periods of high ambient temperature, such as summer. In summer (e.g., T_amb>25℃), the cascade energy utilization system operates in cooling mode. Since heating is not required, the molten salt after the steam generator 5 still enters the primary heat exchanger 6, and after further cooling, it directly returns to the cold molten salt tank 3, no longer entering the secondary heat exchanger 7. A portion of the wastewater (approximately 22-25℃) enters the primary heat exchanger 6, and then enters the first water source heat pump unit 8 to produce domestic hot water. Another portion of the wastewater (approximately 22-25℃) is directly pumped into the second water source heat pump unit 9. At this time, the second water source heat pump unit 9 switches to cooling mode to produce chilled water required for cooling. The chilled water removes heat from the building, and the further heated wastewater enters the subsequent treatment process.

[0031] Specifically, the calculation example of the heat pump cooling energy efficiency ratio (EER) is as follows: With the secondary heat exchanger closed, all the waste heat from the molten salt at 200°C enters the primary heat exchanger. After the primary heat exchanger preheats the wastewater, the 100°C molten salt is directly returned to the cold tank. The raw wastewater (25°C) is directly pumped into the heat pump condenser as the cooling medium. The EER is calculated using the following formula:

[0032] in, This indicates the condensing temperature of the heat pump unit. ; This indicates the evaporation temperature of the heat pump unit; wastewater cooling brings the EER to 6.5.

[0033] When the operating mode command is the normal mode command, the second valve 12, the third valve 13 and the fifth valve 15 are opened, the first valve 11, the fourth valve 14, the sixth valve 16 and the seventh valve 17 are closed, the electric heater 2, the first heat exchanger 6 and the first water source heat pump unit 8 are started and run, and the second heat exchanger 7 and the second water source heat pump unit 9 are kept in the shutdown state.

[0034] For example, the normal mode command is used to control the cascade energy utilization system to operate under normal conditions. In this embodiment, during transitional seasons such as spring and autumn (e.g., 15℃≤T_amb≤25℃), when heating or cooling is not required, the cascade energy utilization system is controlled to operate in normal mode. In normal mode, the molten salt after steam generator 5 still enters the primary heat exchanger 6, and after further cooling, it returns directly to the cold molten salt tank 4, no longer entering the secondary heat exchanger 7. All wastewater enters the primary heat exchanger 6, and then enters the first water source heat pump unit 8 to produce domestic hot water. The second water source heat pump unit 9 for heating / cooling does not operate.

[0035] When the operating mode command is the energy-saving mode command, the first valve 11 is opened, and the second valve 12, the third valve 13, the fourth valve 14, the fifth valve 15, the sixth valve 16 and the seventh valve 17 are closed.

[0036] For example, the energy-saving mode command is used to control the cascade energy utilization system to operate in energy-saving mode. In this embodiment, in the case of insufficient light, the first valve 11 can be opened and all other valves can be closed to prioritize the load demand of electricity and process heat in the plant area. Other domestic hot water and heating / cooling heat pump units can be supported by the mains power.

[0037] The cascade energy utilization system provided by this invention addresses the pain points of existing wastewater treatment plant energy systems, such as high photovoltaic curtailment rates, low heat pump efficiency, severe waste of waste heat, and isolated system operation. It achieves a comprehensive breakthrough over existing technologies by relying on a collaborative architecture of photovoltaic power generation modules, molten salt thermal storage, a two-stage heat exchanger, dual water source heat pumps, and dynamic control. Firstly, the photovoltaic power generation modules prioritize power supply to the electric heaters and two water source heat pump units. Surplus electricity can drive the electric heaters to heat the low-temperature molten salt in the cold molten salt tank to a high temperature and store it in the hot molten salt tank, forming a stable storage buffer from electrical energy to thermal energy. During periods of low photovoltaic output, the hot molten salt tank releases heat to meet the needs of steam preparation and wastewater preheating, replacing grid power or fossil fuel heating and significantly reducing photovoltaic power waste. Secondly, the efficiency bottleneck is overcome by using a two-stage heat exchanger and molten salt waste heat preheating design. Molten salt from the steam generator outlet enters the first-stage heat exchanger via the second valve. The first-stage heat exchanger is also connected to the sewage tank via the fifth valve, allowing the waste heat from the molten salt to preheat the sewage. Simultaneously, the first outlet of the first-stage heat exchanger is connected to the second-stage heat exchanger via the fourth valve. The second-stage heat exchanger is connected to the sewage tank via the seventh valve, allowing the further cooled waste heat from the molten salt to preheat another stream of sewage. The preheated sewage then enters the first and second water source heat pump units, respectively, increasing the heat source temperature of the heat pumps and effectively improving the COP of the heat pumps. This solves the problem of low efficiency in existing heat pump technologies, enabling heat pumps to produce domestic hot water, heating hot water, or chilled water more efficiently. After passing through the steam generator, the molten salt does not entirely return to the cold molten salt tank via the first valve. Instead, it preferentially enters the primary heat exchanger via the second valve to release heat, and some molten salt further enters the secondary heat exchanger via the fourth valve to continue releasing heat. This utilizes all the medium-temperature waste heat that would otherwise be wasted in existing technologies for wastewater preheating, avoiding secondary energy waste and improving the energy efficiency of the molten salt thermal storage system. The control module can adjust the operating status of the electric heater, primary heat exchanger, secondary heat exchanger, and two heat pump units, as well as the opening and closing of various valves, according to the operating mode commands. This allows photovoltaic power generation, molten salt thermal storage, wastewater preheating, and heat pump operation to form a coherent energy flow chain, avoiding the extensive mode of high-quality but low-utilization, reducing energy losses, and thus improving the overall energy efficiency of the entire system. This addresses the long-standing issue of existing technologies having an overall energy efficiency of less than 45%. At the same time, the system's dependence on the power grid and fossil fuels is reduced, alleviating energy cost pressures and aligning with carbon neutrality goals.

[0038] According to an embodiment of the present invention, a scheduling and control method for cascaded energy utilization is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0039] This embodiment provides a scheduling and control method for cascade energy utilization, which can be used in the control module of the cascade energy utilization system described in the above embodiment. Figure 2 This is a flowchart of a scheduling and control method for cascade energy utilization according to an embodiment of the present invention, such as... Figure 2 As shown, the process includes the following steps: Step S201: Obtain the running mode instruction.

[0040] For example, the operation mode command is used to control the operation mode of the cascade energy utilization system. The specific content of the operation mode is described in the relevant content of the above embodiments, and will not be repeated here.

[0041] Step S202: Determine control commands based on operating mode commands.

[0042] For example, the control commands are used to control the operating status of the electric heater, the primary heat exchanger, the secondary heat exchanger, the first water source heat pump unit, the second water source heat pump unit, and multiple valves, so that the cascade energy utilization system operates in the corresponding operating mode.

[0043] Step S203: Control the working status of the electric heater, primary heat exchanger, secondary heat exchanger, first water source heat pump unit, second water source heat pump unit, and multiple valves based on control commands.

[0044] For example, in this embodiment of the application, the control module sends control information to the electric heater, the primary heat exchanger, the secondary heat exchanger, the first water source heat pump unit, the second water source heat pump unit, and multiple valves to control the corresponding working states.

[0045] The cascade energy utilization scheduling and control method provided in this embodiment adjusts the working status of electric heaters, primary heat exchangers, secondary heat exchangers, and two heat pump units, as well as the opening and closing of various valves, according to the operation mode instructions. This allows photovoltaic power generation, molten salt thermal storage, sewage preheating, and heat pump operation to form a coherent energy flow chain, avoiding the extensive mode of high-quality energy being underutilized, reducing energy losses, and thereby improving the overall energy efficiency of the entire system. This addresses the current situation where the overall energy efficiency of existing technologies has long been below 45%. At the same time, the system's dependence on the power grid and fossil fuels is reduced, alleviating energy cost pressures and aligning with the carbon neutrality goal.

[0046] This embodiment provides a scheduling and control method for cascade energy utilization, which can be used in the cascade energy utilization system described in the above embodiment. Figure 3 This is a flowchart of a scheduling and control method for cascade energy utilization according to an embodiment of the present invention, such as... Figure 3 As shown, the process includes the following steps: Step S301: Obtain the operating mode command. For details, please refer to [link to relevant documentation]. Figure 2 Step S201 of the illustrated embodiment will not be described again here.

[0047] Step S302: Determine the control command based on the operating mode command. For details, please refer to [link to relevant documentation]. Figure 2 Step S202 of the illustrated embodiment will not be described again here.

[0048] Step S303 involves controlling the operating status of the electric heater, primary heat exchanger, secondary heat exchanger, first water source heat pump unit, second water source heat pump unit, and multiple valves based on control commands. For details, please refer to [link to relevant documentation]. Figure 2 Step S203 of the illustrated embodiment will not be described again here.

[0049] Step S304: When the cascade energy utilization system is detected to be operating in heating mode, the first real-time photovoltaic output, the first real-time sewage temperature, the first process load power, the first photovoltaic output prediction data, and the first heat load prediction data of the cascade energy utilization system are acquired.

[0050] For example, in this embodiment, the first real-time photovoltaic power output is acquired by a power sensor of the photovoltaic array, and the first real-time sewage temperature is acquired by a temperature sensor of the sewage pipe. The first process load power is acquired by a power monitoring module and serves as input for power balance constraints; the process load may include water pumps, fans, etc. The first photovoltaic power output prediction data is generated by combining historical photovoltaic data and weather forecasts (solar intensity, cloud cover) through a photovoltaic power prediction model, providing a basis for advance scheduling of molten salt thermal storage (to absorb surplus photovoltaic power). The first heat load prediction data may include, but is not limited to, domestic hot water load, winter heating load, and summer cooling load, and can be predicted based on historical energy consumption data (such as hourly load over the past 3 months) combined with a regression model or LSTM neural network. Furthermore, the input parameters in the optimization process can also include the initial wastewater temperature and flow rate, collected by temperature sensors and flow meters through the wastewater pipeline, serving as the basis for heat pump preheating and COP calculation; the temperature (hot molten salt tank outlet temperature, steam generator outlet temperature, and inlet / outlet temperatures of the first / secondary heat exchangers) and flow rate of the molten salt, obtained through temperature sensors and flow meters in the molten salt pipeline, used for waste heat balance constraint calculation; and the state of charge of the molten salt thermal storage system, calculated from the liquid level and temperature sensor data of the hot molten salt tank.

[0051] Step S305: Using the real-time output of the first photovoltaic power, the real-time wastewater temperature, the first process load power, the predicted data of the first photovoltaic output, and the predicted data of the first heat load of the cascade energy utilization system, the pre-constructed optimization scheduling model is solved to obtain the first molten salt electric heating power, the first power of the first water source heat pump unit, the first power of the second water source heat pump unit, the wastewater preheating heat of the first stage heat exchanger, and the wastewater preheating heat of the first and second stage heat exchangers. The optimization scheduling model includes an objective function and a first constraint condition under the heating mode. The objective function is constructed with the goal of minimizing the function value. The function value is obtained by summing the economic item index, the energy storage balance item index, and the energy efficiency tracking item index. The economic item index is determined by the power of the molten salt electric heating power, the power of the first water source heat pump unit, and the power of the second water source heat pump unit. The energy storage balance item index is determined by the molten salt electric heating power. The energy efficiency tracking item index is calculated by the wastewater preheating heat of the first stage heat exchanger and the wastewater preheating heat of the second stage heat exchanger.

[0052] For example, the objective function is:

[0053] in, Indicates the first Each period, This indicates the total number of time periods in the optimization cycle. express Electricity price during the specified time period express Power purchased by the grid during a given time period This represents the energy storage balance weighting coefficient. express The charged state of the molten salt during the time period, This represents the weighting factor for energy efficiency tracking. express The coefficient of performance (COP) of a time-period heat pump is used to characterize the ratio of compressor power to heating capacity during data collection. This represents the optimal performance coefficient of the heat pump during actual operation.

[0054] In the embodiments of this application, The following formula is used to calculate:

[0055] in, Indicates process load power. Indicates the electric heating power of the molten salt; This indicates the power of the heat pump compressor unit, including the power of the first water source heat pump unit in heating mode. The power of the second water source heat pump unit ; This indicates the total power generation capacity of photovoltaics.

[0056] The following formula is used to calculate:

[0057] in, This indicates the efficiency of the molten salt electric heating process. Indicates time interval, Indicates the power of the electric heater; This indicates the maximum thermal storage capacity of the molten salt thermal energy storage system, which is the upper limit of the maximum thermal energy that the system can store. This represents the heat power released by the molten salt to the process side (such as heat exchangers and steam generators), that is, the heat power output by the molten salt at time t. The efficiency (dimensionless) of the molten salt exothermic ("discharge") process represents the degree to which the thermal energy stored in the molten salt is effectively converted into usable thermal energy for the process (energy loss occurs during the exothermic process, which needs to be corrected by efficiency).

[0058] In heating mode, the following formula is used for calculation:

[0059] in, express The coefficient of performance (COP) of the heat pump during the actual operation of the time period is given; the meanings of the other variables will not be elaborated further.

[0060] The first constraints under the heating mode include power balance constraints, waste heat balance constraints, wastewater temperature rise constraints, and equipment operation constraints.

[0061] When the curtailment of photovoltaic power is greater than 0, the power balance constraint is:

[0062] in, express Photovoltaic power generation during a given time period; express The process load power for each time period is measured in kW (kWh) and is a real-time measurement. express Power of the electric heater during the period; express The power of the time-of-use heat pump compressor unit, including the power of the primary water source heat pump unit. The power of the second water source heat pump unit ; express Solar curtailment power during specific time periods.

[0063] The waste heat balance constraint is shown in the following equation:

[0064] in, express The maximum limit of total residual heat of molten salt during a given period, in kW; express The wastewater preheating capacity of the primary heat exchanger during a given period, in kW; This indicates that the secondary heat exchanger is activated in heating mode. In other operating modes, the value is 0; express Wastewater preheating in the secondary heat exchanger during a given period.

[0065] The following formula is used to calculate:

[0066] in, This indicates the mass flow rate of the molten salt. This indicates the inlet temperature of the molten salt as it enters the heat exchange stage (such as a primary heat exchanger). This indicates that the minimum safe temperature for molten salt is 100 degrees Celsius; 0.22 represents a comprehensive coefficient related to the specific heat capacity of molten salt, and the meanings of the other variables will not be elaborated further.

[0067] The following formula is used to calculate:

[0068] in, This indicates the mass flow rate of wastewater on the first-stage heat exchanger side (unit: kg / s). This indicates the specific heat capacity of wastewater. This indicates the temperature rise of the wastewater after passing through the primary heat exchanger.

[0069] The following formula is used to calculate:

[0070] in, This indicates the mass flow rate of wastewater on the secondary heat exchanger side (unit: kg / s). This indicates the temperature rise of the wastewater after passing through the secondary heat exchanger.

[0071] The wastewater temperature rise constraint is shown in the following formula:

[0072]

[0073] in, express Temperature rise of wastewater on the primary heat exchanger side during a given period; express Mass flow rate of wastewater on the first-stage heat exchanger side during the time period. express The mass flow rate of wastewater on the secondary heat exchanger side during the time period; the meanings of the other variables will not be elaborated further.

[0074] Equipment operating constraints include molten salt system constraints and heat pump system constraints. The molten salt system constraints are shown in the following formula:

[0075] in, This indicates the maximum power of the electric heater, typically 2000 kW; This indicates the minimum charge state for preventing solidification, which can be 0.2. This indicates the state of maximum charge to prevent overheating, and can be 0.95. This represents the maximum rate of change of the state of charge, which can be 0.1 per 15 minutes.

[0076] The constraints of a heat pump system are shown in the following equation:

[0077] in, This indicates the compressor's minimum power; it is 200kW in heating mode and 200kW in cooling mode. This indicates the compressor's maximum power: 800kW in heating mode and 700kW in cooling mode. This indicates the lower limit of the condensing temperature, which is 50 degrees Celsius in heating mode and 30 degrees Celsius in cooling mode. This indicates the upper limit of the condensing temperature, which is 70 degrees Celsius in heating mode and 45 degrees Celsius in cooling mode. This represents the protective shutdown threshold, which is 3.5 in heating mode and 4.8 in cooling mode. The meanings of the other variables will not be elaborated here.

[0078] Furthermore, the accuracy of scheduling control can be improved through adaptive weighting. The specific adaptive adjustment of the weights can be shown in the following formula:

[0079]

[0080] in, and This represents the weighting coefficient; the meanings of the other variables will not be elaborated further.

[0081] Step S306: The cascade energy utilization system is scheduled using the first molten salt electric heating power, the first power of the first water source heat pump unit, the first power of the second water source heat pump unit, the wastewater preheating heat of the first stage heat exchanger, and the wastewater preheating heat of the first and second stage heat exchangers.

[0082] For example, scheduling parameters are determined based on the first molten salt electric heating power, the first power of the first water source heat pump unit, the first power of the second water source heat pump unit, the wastewater preheating heat of the first stage heat exchanger, and the wastewater preheating heat of the first and second stage heat exchangers, and the cascade energy utilization system is scheduled and controlled. The specific control process can be determined according to the requirements, and the embodiments of this application do not make specific limitations.

[0083] The cascade energy utilization scheduling and control method provided in this embodiment is based on an optimized scheduling model for heating mode operation scheduling. It leverages comprehensive optimization of economic, energy storage balance, and energy efficiency tracking factors, combined with real-time photovoltaic output and forecast data, first real-time wastewater temperature, first process load power, and first heat load forecast data. On one hand, it prioritizes the consumption of surplus photovoltaic power and rationally allocates molten salt electric heating power and water source heat pump unit power, reducing grid power purchases and ineffective energy consumption during periods of high electricity prices, thus effectively lowering system operating costs. On the other hand, it utilizes molten salt waste heat to preheat wastewater in a cascade manner, ensuring that the wastewater entering the water... The increased wastewater temperature of the water source heat pump unit significantly improves the coefficient of performance (COP) of the heat pump, avoids the waste of molten salt mid-temperature waste heat, and simultaneously allows the molten salt thermal storage system to approach a near-equilibrium state of charge by adjusting the electric heating power of the molten salt, preventing overcharging and over-discharging, extending the service life of the thermal storage equipment. It can also flexibly respond to changes in photovoltaic output and heat load, significantly reducing the photovoltaic curtailment rate and enhancing the level of clean energy utilization. Furthermore, under the constraints of the heating mode, it ensures that the operating parameters of equipment such as electric heaters and water source heat pump units are within safe ranges, maintaining the continuity of system energy transfer, stably providing energy to the heat load, and improving heating reliability. Ultimately, from multiple dimensions such as economic cost, energy efficiency, energy storage and equipment lifespan, clean energy utilization, and system operational stability, the overall performance of the cascade energy utilization system in heating mode is comprehensively improved, achieving multi-objective synergistic optimization.

[0084] This embodiment provides a scheduling and control method for cascade energy utilization, which can be used in the cascade energy utilization system described in the above embodiment. Figure 4 This is a flowchart of a scheduling and control method for cascade energy utilization according to an embodiment of the present invention, such as... Figure 4 As shown, the process includes the following steps: Step S401: Obtain the operating mode command. For details, please refer to [link to relevant documentation]. Figure 3 Step S301 of the illustrated embodiment will not be described again here.

[0085] Step S402: Determine the control command based on the operating mode command. For details, please refer to [link to relevant documentation]. Figure 3 Step S302 of the illustrated embodiment will not be described again here.

[0086] Step S403 involves controlling the operating status of the electric heater, primary heat exchanger, secondary heat exchanger, first water source heat pump unit, second water source heat pump unit, and multiple valves based on control commands. For details, please refer to [link to relevant documentation]. Figure 3 Step S303 of the illustrated embodiment will not be described again here.

[0087] Step S404: When the cascade energy utilization system is detected to be operating in cooling mode, acquire the second real-time photovoltaic power output, second real-time sewage temperature, second process load power, second photovoltaic power output prediction data, and second heat load prediction data of the cascade energy utilization system.

[0088] For example, the specific methods for acquiring data are described in the above embodiments, and will not be repeated here.

[0089] Step S405: Using the second real-time photovoltaic power output, second real-time sewage temperature, second process load power, second photovoltaic power output prediction data, and second heat load prediction data of the cascade energy utilization system, the pre-constructed optimization scheduling model is solved to obtain the second molten salt electric heating power, the second power of the first water source heat pump unit, the second power of the second water source heat pump unit, and the sewage preheating heat of the second primary heat exchanger. The optimization scheduling model includes an objective function and a second constraint condition under the cooling mode. The objective function is constructed with the goal of minimizing the function value. The function value is obtained by summing the economic item index, the energy storage balance item index, and the energy efficiency tracking item index. The economic item index is determined by the molten salt electric heating power and the heat pump compressor power. The energy storage balance item index is determined by the molten salt electric heating power. The energy efficiency tracking item index is calculated by the sewage preheating heat of the primary heat exchanger and the sewage preheating heat of the secondary heat exchanger.

[0090] For example, the specific content of the objective function is described in the above embodiments and will not be repeated here. In cooling mode, the second constraint includes... For the remaining constraints, please refer to the relevant description of the constraints under heating mode, which will not be repeated here.

[0091] Step S406 involves scheduling the cascade energy utilization system using the second molten salt electric heating power, the second power of the first water source heat pump unit, the second power of the second water source heat pump unit, and the wastewater preheating heat of the second stage heat exchanger. For illustrative examples, please refer to the description of the relevant content in the above embodiments; it will not be repeated here.

[0092] The cascade energy utilization scheduling and control method provided in this embodiment is based on an optimized scheduling model for cooling mode operation scheduling. Utilizing real-time and predicted output of the second photovoltaic system and real-time wastewater temperature data, it comprehensively optimizes economic, energy storage balance, and energy efficiency tracking factors. On one hand, it prioritizes the use of surplus photovoltaic power to drive molten salt electric heating or heat pump operation, reducing grid power purchases during periods of high electricity prices. Simultaneously, it precisely controls the molten salt electric heating power and heat pump compressor power to avoid ineffective high energy consumption and effectively reduce system operating costs. On the other hand, it utilizes the preheating of wastewater by the primary heat exchanger to optimize the heat pump heat source state, improving the cooling performance of the water source heat pump unit. The Energy Efficiency Ratio (EER) enables heat pumps to output more cooling capacity with lower electrical energy input, reducing energy consumption per unit of cooling capacity. Simultaneously, the molten salt electric heating power regulates the charge state of the molten salt storage, preventing overcharging or over-discharging and extending the lifespan of the thermal storage equipment. Furthermore, when photovoltaic output fluctuates, molten salt energy storage can flexibly "charge and absorb photovoltaic power" or "discharge to assist cooling," significantly reducing photovoltaic curtailment rates and increasing the proportion of clean energy. Moreover, the second constraint in cooling mode ensures that the operating parameters of electric heaters, heat pumps, and other equipment remain within safe ranges, maintaining the continuity of energy transfer and stably providing cooling capacity to meet chilled water demand, ensuring the reliability and continuity of cooling. Ultimately, from the dimensions of economic cost control, improved energy utilization efficiency, optimized energy storage and equipment lifespan, enhanced clean energy absorption, and system operational stability, the overall performance of the cascade energy utilization system in cooling mode is comprehensively improved, achieving multi-objective synergistic optimization.

[0093] This embodiment also provides a scheduling and control device for cascade energy utilization, which is used to implement the above embodiments and preferred embodiments; details already described will not be repeated. As used below, the term "module" can refer to a combination of software and / or hardware that implements a predetermined function. Although the device described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0094] This embodiment provides a scheduling and control device for cascade energy utilization, used to execute the scheduling and control method for cascade energy utilization described in the above embodiment, such as... Figure 5 As shown, it includes: The first acquisition unit 501 is used to acquire the running mode instruction; Determining unit 502 is used to determine control commands based on operating mode commands; The control unit 503 is used to control the operating status of the electric heater, the primary heat exchanger, the secondary heat exchanger, the first water source heat pump unit, the second water source heat pump unit, and multiple valves based on control commands.

[0095] In some alternative embodiments, the above-described apparatus further includes: The second acquisition module is used to acquire the first real-time photovoltaic power output, the first real-time sewage temperature, the first process load power, the first photovoltaic power output prediction data, and the first heat load prediction data of the cascade energy utilization system when it is detected that the cascade energy utilization system is operating in the heating mode. The first solution module is used to solve a pre-built optimization scheduling model using the first real-time photovoltaic power output, first real-time sewage temperature, first process load power, first photovoltaic power output prediction data, and first heat load prediction data of the cascade energy utilization system. This results in the first molten salt electric heating power, the first power of the first water source heat pump unit, the first power of the second water source heat pump unit, the sewage preheating heat of the first stage heat exchanger, and the sewage preheating heat of the first and second stage heat exchangers. The optimization scheduling model includes an objective function and first constraints under the heating mode. The objective function is constructed with the goal of minimizing the function value. The function value is obtained by summing the economic indicators, energy storage balance indicators, and energy efficiency tracking indicators. The economic indicators are determined by the molten salt electric heating power, the power of the first and second water source heat pump units, the energy storage balance indicators are determined by the molten salt electric heating power, and the energy efficiency tracking indicators are calculated using the sewage preheating heat of the first and second stage heat exchangers. The first scheduling module is used to schedule the cascade energy utilization system by means of the first molten salt electric heating power, the first power of the first water source heat pump unit, the first power of the second water source heat pump unit, the wastewater preheating heat of the first stage heat exchanger, and the wastewater preheating heat of the first and second stage heat exchangers.

[0096] In some alternative embodiments, the above-described apparatus further includes: The third acquisition module is used to acquire the second real-time photovoltaic power output, second real-time sewage temperature, second process load power, second photovoltaic power output prediction data, and second heat load prediction data of the cascade energy utilization system when it is detected that the cascade energy utilization system is operating in the cooling mode. The second solution module uses the real-time output of the second photovoltaic power, the real-time wastewater temperature, the second process load power, the predicted data of the second photovoltaic output, and the predicted data of the second heat load of the cascade energy utilization system to solve the pre-constructed optimization scheduling model, and obtains the second molten salt electric heating power, the second power of the first water source heat pump unit, the second power of the second water source heat pump unit, and the wastewater preheating heat of the second primary heat exchanger. The optimization scheduling model includes an objective function and a second constraint condition under the cooling mode. The objective function is constructed with the goal of minimizing the function value. The function value is obtained by summing the economic item index, the energy storage balance item index, and the energy efficiency tracking item index. The economic item index is determined by the molten salt electric heating power and the heat pump compressor power. The energy storage balance item index is determined by the molten salt electric heating power. The energy efficiency tracking item index is calculated by the wastewater preheating heat of the primary heat exchanger and the wastewater preheating heat of the secondary heat exchanger. The second scheduling module is used to schedule the cascade energy utilization system using the second molten salt electric heating power, the second power of the first water source heat pump unit, the second power of the second water source heat pump unit, and the wastewater preheating heat of the second stage heat exchanger.

[0097] In some alternative implementations, the objective function is:

[0098] in, Indicates the first Each period, This indicates the total number of time periods in the optimization cycle. express Electricity price during the specified time period express Power purchased by the grid during a given time period This represents the energy storage balance weighting coefficient. express The charged state of the molten salt during the time period, This represents the weighting factor for energy efficiency tracking. express The coefficient of performance (COP) of a time-limited heat pump in actual operation. This represents the optimal performance coefficient of the heat pump during actual operation.

[0099] The cascade energy utilization scheduling and control device provided in this embodiment of the invention can execute the cascade energy utilization scheduling and control method provided in any embodiment of the invention, and has the corresponding functional modules and beneficial effects for executing the method. Further functional descriptions of the above modules and units are the same as those in the corresponding embodiments described above, and will not be repeated here.

[0100] Figure 6 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention.

[0101] The following is a detailed reference. Figure 6 This diagram illustrates a suitable structural design for implementing an electronic device according to embodiments of the present invention. The electronic device may include a processor (e.g., a central processing unit, graphics processor, etc.) 601, which can perform various appropriate actions and processes based on a program stored in read-only memory (ROM) 602 or a program loaded from memory 608 into random access memory (RAM) 603. RAM 603 also stores various programs and data required for the operation of the electronic device. The processor 601, ROM 602, and RAM 603 are interconnected via a bus 604. An input / output (I / O) interface 605 is also connected to the bus 604.

[0102] Typically, the following devices can be connected to I / O interface 605: input devices 606 including, for example, touchscreens, touchpads, keyboards, mice, cameras, microphones, accelerometers, gyroscopes, etc.; output devices 607 including, for example, liquid crystal displays (LCDs), speakers, vibrators, etc.; memory devices 608 including, for example, magnetic tapes, hard disks, etc.; and communication devices 609. Communication device 609 allows electronic devices to communicate wirelessly or wiredly with other devices to exchange data. Although Figure 6 Electronic devices with various devices are shown, but it should be understood that it is not required to implement or have all of the devices shown, and more or fewer devices may be implemented or have instead.

[0103] In particular, according to embodiments of the present invention, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of the present invention include a computer program product comprising a computer program carried on a non-transitory computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via a communication device 609, or installed from a memory 608, or installed from a ROM 602. When the computer program is executed by the processor 601, it performs the functions defined in the cascade energy utilization scheduling control method of the embodiments of the present invention.

[0104] Figure 6 The electronic device shown is merely an example and should not be construed as limiting the functionality and scope of use of the embodiments of the present invention.

[0105] This invention also provides a computer-readable storage medium. The methods described above according to embodiments of the invention can be implemented in hardware or firmware, or implemented as computer code that can be recorded on a storage medium, or implemented as computer code downloaded via a network and originally stored on a remote storage medium or a non-transitory machine-readable storage medium and then stored on a local storage medium. Thus, the methods described herein can be processed by software stored on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. The storage medium can be a magnetic disk, optical disk, read-only memory, random access memory, flash memory, hard disk, or solid-state drive, etc.; further, the storage medium can also include combinations of the above types of memory. It is understood that computers, processors, microprocessor controllers, or programmable hardware include storage components capable of storing or receiving software or computer code. When the software or computer code is accessed and executed by the computer, processor, or hardware, the tiered energy utilization scheduling and control method shown in the above embodiments is implemented.

[0106] A portion of this invention can be applied as a computer program product, such as computer program instructions, which, when executed by a computer, can invoke or provide the methods and / or technical solutions according to the invention through the operation of the computer. Those skilled in the art will understand that the forms in which computer program instructions exist in a computer-readable medium include, but are not limited to, source files, executable files, installation package files, etc. Correspondingly, the ways in which computer program instructions are executed by a computer include, but are not limited to: the computer directly executing the instructions, or the computer compiling the instructions and then executing the corresponding compiled program, or the computer reading and executing the instructions, or the computer reading and installing the instructions and then executing the corresponding installed program. Here, the computer-readable medium can be any available computer-readable storage medium or communication medium accessible to a computer.

[0107] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A cascade energy utilization system, characterized by, The system comprises a photovoltaic power generation module, an electric heater, a hot molten salt tank, a cold molten salt tank, a steam generator, a first-level heat exchanger, a second-level heat exchanger, a first water source heat pump unit, a second water source heat pump unit, a plurality of valves, and a control module, wherein the plurality of valves comprise a first valve, a second valve, a third valve, a fourth valve, a fifth valve, a sixth valve, and a seventh valve. The photovoltaic power generation module is configured to supply power to the electric heater, the first water source heat pump unit, and the second water source heat pump unit; the outlet of the cold molten salt tank is connected to the inlet of the hot molten salt tank via the electric heater; the outlet of the hot molten salt tank is connected to the inlet of the steam generator; the outlet of the steam generator is connected to the cold molten salt tank via the first valve and to the inlet of the first-level heat exchanger via the second valve; the first outlet of the first-level heat exchanger is connected to the cold molten salt tank via the third valve and to the first inlet of the second-level heat exchanger via the fourth valve; the second outlet of the first-level heat exchanger is connected to the inlet of the first water source heat pump unit; the target port of the first-level heat exchanger is connected to the sewage pool via the fifth valve; the first outlet of the second-level heat exchanger is connected to the cold molten salt tank, and the second outlet of the second-level heat exchanger is connected to the second water source heat pump unit; the second water source heat pump unit is connected to the target port of the first-level heat exchanger via the sixth valve and the fifth valve in sequence; the second inlet of the second-level heat exchanger is connected to the sewage pool via the seventh valve and the fifth valve in sequence; and the control module is configured to control the working states of the electric heater, the first-level heat exchanger, the second-level heat exchanger, the first water source heat pump unit, the second water source heat pump unit, and the plurality of valves according to operation mode instructions.

2. The system of claim 1, wherein, The operation mode instructions comprise a heating mode instruction, a cooling mode instruction, a normal mode instruction, and an energy-saving mode instruction. When the operation mode instruction is the heating mode instruction, the control module is configured to control the first valve, the third valve, and the sixth valve to be closed, the second valve, the fourth valve, the fifth valve, and the seventh valve to be opened, control the electric heater, the first-level heat exchanger, the second-level heat exchanger, and the first water source heat pump unit to start running, and control the second water source heat pump unit to run in the heating mode. When the operation mode instruction is the cooling mode instruction, the control module is configured to control the first valve, the fourth valve, and the seventh valve to be closed, the second valve, the third valve, the fifth valve, and the sixth valve to be opened, control the electric heater, the first-level heat exchanger, the second-level heat exchanger, and the first water source heat pump unit to start running, and control the second water source heat pump unit to run in the cooling mode. When the operation mode instruction is the normal mode instruction, the control module is configured to control the second valve, the third valve, and the fifth valve to be opened, the first valve, the fourth valve, the sixth valve, and the seventh valve to be closed, control the electric heater, the first-level heat exchanger, and the first water source heat pump unit to start running, and control the second-level heat exchanger and the second water source heat pump unit to be in a shutdown state. When the operation mode instruction is the energy-saving mode instruction, the control module is configured to control the first valve to be opened and the second valve, the third valve, the fourth valve, the fifth valve, the sixth valve, and the seventh valve to be closed.

3. A method for scheduling control of step energy utilization, characterized by, The method is applied to the cascade energy utilization system in claim 1 or 2, and the method comprises: obtaining an operation mode instruction; determining a control instruction based on the operation mode instruction; controlling the working states of the electric heater, the primary heat exchanger, the secondary heat exchanger, the first water source heat pump unit, the second water source heat pump unit and the plurality of valves based on the control instruction.

4. The method of claim 3, wherein, The method further comprises: when it is monitored that the cascade energy utilization system operates in the heating mode, obtaining a first real-time photovoltaic output, a first real-time sewage temperature, a first process load power, first photovoltaic output prediction data and first heat load prediction data of the cascade energy utilization system; solving a pre-constructed optimization scheduling model by using the first real-time photovoltaic output, the first real-time sewage temperature, the first process load power, the first photovoltaic output prediction data and the first heat load prediction data of the cascade energy utilization system to obtain a first molten salt electric heating power, a first power of the first water source heat pump unit, a first power of the second water source heat pump unit, a first primary heat exchanger sewage preheating amount and a first secondary heat exchanger sewage preheating amount, wherein the optimization scheduling model comprises a target function and a first constraint condition in the heating mode, the target function is constructed with a minimum function value as a target, and the function value is obtained by summing an economic item index, an energy storage balancing item index and an energy efficiency tracking item index, the economic item index is determined by the molten salt electric heating power, the powers of the first water source heat pump unit and the second water source heat pump unit, the energy storage balancing item index is determined by the molten salt electric heating power, and the energy efficiency tracking item index is calculated by the primary heat exchanger sewage preheating amount and the secondary heat exchanger sewage preheating amount; scheduling the cascade energy utilization system by using the first molten salt electric heating power, the first power of the first water source heat pump unit, the first power of the second water source heat pump unit, the first primary heat exchanger sewage preheating amount and the first secondary heat exchanger sewage preheating amount.

5. The method according to claim 3 or 4, characterized in that, The method further comprises: when it is monitored that the cascade energy utilization system operates in the cooling mode, obtaining a second real-time photovoltaic output, a second real-time sewage temperature, a second process load power, second photovoltaic output prediction data and second heat load prediction data of the cascade energy utilization system; Solve the pre-constructed optimization scheduling model by using the second photovoltaic real-time output, the second real-time sewage temperature, the second process load power, the second photovoltaic output prediction data, and the second heat load prediction data of the cascade energy utilization system, to obtain the second molten salt electric heating power, the second power of the first water source heat pump unit, the second power of the second water source heat pump unit, and the second primary heat exchanger sewage preheating amount, the optimization scheduling model includes an objective function and a second constraint condition in a refrigeration mode, the objective function is constructed with the minimum function value as the target, the function value is obtained by summing an economic item index, an energy storage balancing item index, and an energy efficiency tracking item index, the economic item index is determined by the molten salt electric heating power and the heat pump compressor power, the energy storage balancing item index is determined by the molten salt electric heating power, and the energy efficiency tracking item index is calculated by the primary heat exchanger sewage preheating amount and the secondary heat exchanger sewage preheating amount; The cascade energy utilization system is scheduled by using the second molten salt electric heating power, the second power of the first water source heat pump unit, the second power of the second water source heat pump unit, and the second primary heat exchanger sewage preheating amount.

6. The method of claim 4, wherein, The objective function is: wherein, represents the number of periods, represents the total number of optimization periods, represents the number of periods, represents the grid electricity price of the period, represents the grid electricity purchase power of the period, represents the grid electricity purchase power of the period, represents the energy storage balancing weight coefficient, represents the number of periods, represents the molten salt state of charge of the period, represents the energy efficiency tracking weight coefficient, represents the number of periods, represents the actual coefficient of performance of the heat pump in operation in the period, represents the optimal coefficient of performance of the heat pump in operation.​ 7. A dispatch control device of step energy utilization, characterized by, The device for performing the scheduling control method for cascade energy utilization of claim 3 comprises: A first acquisition unit configured to acquire an operation mode instruction; A determination unit configured to determine a control instruction based on the operation mode instruction; A control unit configured to control the working states of the electric heater, the primary heat exchanger, the secondary heat exchanger, the first water source heat pump unit, the second water source heat pump unit, and the plurality of valves based on the control instruction.

8. An electronic device, comprising: Comprise: A memory and a processor, which are communicatively connected, the memory stores computer instructions, and the processor executes the computer instructions to perform the scheduling control method for cascade energy utilization of any one of claims 3 to 6.

9. A computer-readable storage medium, characterized in that, The computer readable storage medium stores computer instructions, and the computer instructions are used to make the computer perform the scheduling control method for cascade energy utilization of any one of claims 3 to 6.

10. A computer program product, characterised in that, The computer instructions are used to make the computer perform the scheduling control method for cascade energy utilization of any one of claims 3 to 6.

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