Multi-grade heat energy supply system and control method thereof

Abstract

The application discloses a multi-grade heat energy supply system, which comprises a first heat storage water tank, a second heat storage water tank, a third heat storage water tank, a steam storage tank, a control device and a low-temperature water supply mechanism, a medium-temperature water supply mechanism, a high-temperature heat pump mechanism and an ultrahigh-temperature heat pump mechanism which are electrically connected with the control device respectively; the low-temperature water supply mechanism, the first heat storage water tank, the medium-temperature water supply mechanism, the second heat storage water tank, the high-temperature heat pump mechanism, the third heat storage water tank and the steam storage tank are sequentially connected; the temperature of the hot water stored in the first heat storage water tank, the temperature of the hot water stored in the second heat storage water tank and the temperature of the hot water stored in the third heat storage water tank gradually increase; the system disclosed by the application comprises multiple water supply mechanisms with different temperatures, heat is taken from each other among the multiple water supply mechanisms to realize preparation of hot water with different temperatures, the system can provide a heat source with a temperature of 40 DEG C to 120 DEG C for a park, meets the heat source demand of the park with a wide temperature range and is convenient to manage and plan.

Description

Technical Field

[0001] This invention relates to the field of heat pump technology, and in particular to a multi-grade heat energy supply system and its control method. Background Technology

[0002] Current industrial parks integrate living, office, and production functions. This means that industrial parks have a demand for 40°C heating in office areas and 60°C hot water in dormitory areas. Furthermore, the production and manufacturing processes in the park require a large amount of 90°C hot water and 120°C steam for drying, sterilization, and other processes. Therefore, the demand for heat source quality in current industrial parks is diversified.

[0003] For existing industrial parks that need to meet the demand for multiple heat sources, separate heat supply systems are used to output heat sources in different temperature ranges. For example, office buildings have independent heating systems, 60℃ domestic hot water uses independent heat pump systems or electric heating systems, and 90℃ high-temperature process hot water and 120℃ steam are supplied by municipal pipelines. The heating system of the entire park cannot achieve clean and unified operation, resulting in inefficient use of heat sources, high heating energy consumption, high operating costs, and complex and costly management.

[0004] It is evident that existing technologies still need improvement and enhancement. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a multi-grade heat energy supply system that is integrated as a whole, convenient for management and overall planning, and can meet the heat source needs of industrial parks with a wide temperature range.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A multi-grade heat energy supply system includes a first hot water storage tank, a second hot water storage tank, a third hot water storage tank, a steam storage tank, a control device, and a low-temperature water supply mechanism, a medium-temperature water supply mechanism, a high-temperature heat pump mechanism, and an ultra-high-temperature heat pump mechanism, all electrically connected to the control device. The low-temperature water supply mechanism, the first hot water storage tank, the medium-temperature water supply mechanism, the second hot water storage tank, the high-temperature heat pump mechanism, the third hot water storage tank, and the steam storage tank are connected in sequence. The temperature of the hot water stored in the first hot water storage tank, the second hot water storage tank, and the third hot water storage tank gradually increases.

[0008] In the multi-grade heat energy supply system, the low-temperature water supply mechanism includes a first solar water supply unit and a low-temperature heat pump mechanism, and the medium-temperature water supply mechanism includes a second solar water supply unit and a medium-temperature heat pump mechanism. The output ends of the first solar water supply unit and the low-temperature heat pump mechanism are respectively connected to the input end of the first hot water storage tank. The output end of the first hot water storage tank is connected to the input end of the second hot water storage tank through the medium-temperature heat pump mechanism. The output end of the second solar water supply unit is connected to the input end of the second hot water storage tank. The first solar water supply unit, the low-temperature heat pump mechanism, the second solar water supply unit, and the medium-temperature heat pump mechanism are respectively electrically connected to the control device.

[0009] In the multi-grade heat energy supply system, the first solar water supply unit includes a photovoltaic thermal module and a first delivery pump, which are electrically connected to the control device. The photovoltaic thermal module, the first delivery pump, and the first hot water storage tank form a circulation loop. The low-temperature heat pump mechanism includes a low-temperature heat pump unit and a second delivery pump, which are electrically connected to the control device. The low-temperature heat pump unit, the second delivery pump, and the first hot water storage tank form a circulation loop.

[0010] In the multi-grade heat energy supply system, the second solar water supply unit includes a fourth hot water storage tank, a flat-plate collector, a third delivery pump, and a fourth delivery pump, all electrically connected to the control device. The flat-plate collector, the third delivery pump, and the fourth hot water storage tank form a circulation loop. The output end of the fourth hot water storage tank is connected to the input end of the second hot water storage tank via the fourth delivery pump. The medium-temperature heat pump mechanism includes a medium-temperature heat pump unit, a fifth delivery pump, and a sixth delivery pump, all electrically connected to the control device. The first hot water storage tank, the fifth delivery pump, and the medium-temperature heat pump unit form a circulation loop. The medium-temperature heat pump unit, the sixth delivery pump, and the second hot water storage tank also form a circulation loop.

[0011] In the multi-grade heat energy supply system, the high-temperature heat pump mechanism includes a seventh delivery pump, an eighth delivery pump, and a high-temperature heat pump unit, which are electrically connected to the control device respectively. The second hot water storage tank, the seventh delivery pump, and the high-temperature heat pump unit form a circulation loop. The high-temperature heat pump mechanism, the eighth delivery pump, and the third hot water storage tank form a circulation loop.

[0012] In the multi-grade heat energy supply system, the ultra-high temperature heat pump mechanism includes a ninth delivery pump and an ultra-high temperature heat pump unit, which are electrically connected to the control device respectively. The ultra-high temperature heat pump unit, the ninth delivery pump, and the third hot water storage tank form a circulation loop. The input end of the ultra-high temperature heat pump mechanism is also used to connect to an external water source, and the output end of the ultra-high temperature heat pump mechanism is also connected to the steam storage tank.

[0013] In the multi-grade heat energy supply system, the low-temperature heat pump unit includes a first compressor, a first evaporator, a first condenser, and a first expansion valve. The first compressor, the first evaporator, the first expansion valve, and the first condenser are connected end to end in sequence. The first condenser is used to absorb heat from the air, and the first evaporator is used to increase the temperature of the liquid in the first hot water storage tank. The first compressor is electrically connected to the control device.

[0014] In the multi-grade heat energy supply system, the ultra-high temperature heat pump unit includes a fourth compressor, a fourth evaporator, a fourth condenser, a fourth expansion valve, and a flash tank. The fourth compressor, fourth evaporator, fourth expansion valve, and fourth condenser are connected sequentially. The fourth condenser is used to extract heat from the third hot water storage tank. The input end of the fourth evaporator is also used to connect to an external water source. The output end of the fourth evaporator is also connected to the input end of the flash tank. The output end of the flash tank is connected to the steam storage tank.

[0015] This application also provides a control method for a multi-grade heat energy supply system, wherein the control method is used to implement the operation control of the multi-grade heat energy supply system as described above, and the control method includes the following steps:

[0016] The ambient radiation intensity is obtained, and the working mode of the multi-grade heat energy supply system is adjusted according to the ambient radiation intensity. The working mode includes a sunny day mode and a cloudy / rainy day mode.

[0017] When the working mode is sunny mode, the control device first controls the second solar water supply unit to start working. When the real-time temperature inside the second hot water storage tank meets the preset second temperature requirement, the control device controls the first solar water supply unit to start working. When the real-time temperature inside the first hot water storage tank meets the preset first temperature requirement, the control device controls the high-temperature heat pump mechanism to start working. When the real-time temperature inside the third hot water storage tank meets the preset third temperature requirement, the control device controls the ultra-high temperature heat pump mechanism to start working, so that the internal temperature of the steam storage tank meets the preset fourth temperature requirement.

[0018] When the working mode is the rainy day mode, the control device first controls the low-temperature heat pump mechanism to start working. When the real-time temperature inside the first hot water storage tank meets the preset first temperature requirement, the control device controls the medium-temperature heat pump mechanism to start working. When the real-time temperature inside the second hot water storage tank meets the preset second temperature requirement, the control device controls the high-temperature heat pump mechanism to start working. When the real-time temperature inside the third hot water storage tank meets the preset third temperature requirement, the control device controls the ultra-high temperature heat pump mechanism to start working, so that the internal temperature of the steam storage tank meets the preset fourth temperature requirement.

[0019] In the control method of the multi-grade heat energy supply system, the step before obtaining the ambient radiation intensity further includes:

[0020] The system acquires real-time time. When the real-time time is within the rest period, the control device controls the low-temperature heat pump mechanism to start working. When the real-time temperature inside the first hot water storage tank meets the preset first temperature requirement, the control device controls the low-temperature heat pump mechanism to return to standby mode.

[0021] When the real-time period is during production time, the ambient radiation intensity is obtained.

[0022] Beneficial effects:

[0023] This invention provides a multi-grade heat energy supply system, including multiple water supply mechanisms that can output different heat sources. The multiple water supply mechanisms can mutually extract heat to prepare hot water at different temperatures, enabling the system to provide heat sources of 40℃ to 120℃ to the industrial park, meeting the heat source needs of the industrial park in a wide temperature range. The system is integrated as a whole, which is convenient for management and overall planning, and reduces the difficulty of operation and maintenance. Attached Figure Description

[0024] Figure 1 System structure diagram of the multi-grade heat energy supply system provided by the present invention;

[0025] Figure 2 A first logic flowchart of the control method provided by the present invention;

[0026] Figure 3 The second logic flowchart of the control method provided by the present invention.

[0027] Explanation of main component symbols: 1-First hot water storage tank, 2-Second hot water storage tank, 3-Third hot water storage tank, 4-Steam storage tank, 51-Photovoltaic thermal module, 52-First transfer pump, 53-Low temperature heat pump unit, 54-Second transfer pump, 61-Fourth hot water storage tank, 62-Plate-plate collector, 63-Third transfer pump, 64-Fourth transfer pump, 65-Medium temperature heat pump unit, 66-Fifth transfer pump, 67-Sixth transfer pump, 71-Seventh transfer pump, 72-Eighth transfer pump, 73-High temperature heat pump unit, 81-Ninth transfer pump, 82-Ultra-high temperature heat pump unit. Detailed Implementation

[0028] This invention provides a multi-grade heat energy supply system and its control method. To make the objectives, technical solutions and effects of this invention clearer and more explicit, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0029] In the description of this invention, it should be understood that the terms "installation" and "connection" should be interpreted broadly, and those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0030] Please see Figure 1 This invention provides a multi-grade heat energy supply system, including a first hot water storage tank 1, a second hot water storage tank 2, a third hot water storage tank 3, a steam storage tank 4, a control device, and a low-temperature water supply mechanism, a medium-temperature water supply mechanism, a high-temperature heat pump mechanism, and an ultra-high-temperature heat pump mechanism, all electrically connected to the control device. The low-temperature water supply mechanism, the first hot water storage tank 1, the medium-temperature water supply mechanism, the second hot water storage tank 2, the high-temperature heat pump mechanism, the third hot water storage tank 3, and the steam storage tank 4 are connected in sequence. The temperature of the hot water stored in the first hot water storage tank 1, the second hot water storage tank 2, and the third hot water storage tank 3 gradually increases.

[0031] This application discloses a multi-grade heat energy supply system, including a low-temperature water supply mechanism, a medium-temperature water supply mechanism, a high-temperature heat pump mechanism, and an ultra-high-temperature heat pump mechanism. The interconnected water supply mechanism and heat pump mechanism mutually extract heat to prepare hot water at different temperatures, thus outputting heat sources at different temperatures. This allows the system to provide heat sources of 40℃ to 120℃ to the industrial park, meeting the wide temperature range heat source needs of the industrial park. Furthermore, the heat energy supply system is integrated as a whole, which facilitates management and coordination and reduces the difficulty of operation and maintenance.

[0032] In this embodiment, the first hot water storage tank 1 is used to store hot water for heating at 35℃-40℃, the second hot water storage tank 2 is used to store domestic hot water at 55℃-60℃, the third hot water storage tank 3 is used to store process hot water at 85℃-90℃, and the steam storage tank 4 is used to store process steam at 110℃-120℃.

[0033] In this embodiment, the control device includes multiple control chips, which may be STM32 series control chips. The control device is used to realize the operation control of the heat pump unit and the operation control of the transfer pump. Its control principle is existing technology and will not be described in detail here.

[0034] Further, please refer to Figure 1The low-temperature water supply mechanism includes a first solar water supply unit and a low-temperature heat pump mechanism, and the medium-temperature water supply mechanism includes a second solar water supply unit and a medium-temperature heat pump mechanism. The output end of the first solar water supply unit and the output end of the low-temperature heat pump mechanism are respectively connected to the input end of the first hot water storage tank 1. The output end of the first hot water storage tank 1 is connected to the input end of the second hot water storage tank 2 through the medium-temperature heat pump mechanism. The output end of the second solar water supply unit is connected to the input end of the second hot water storage tank 2. The first solar water supply unit, the low-temperature heat pump mechanism, the second solar water supply unit, and the medium-temperature heat pump mechanism are respectively electrically connected to the control device.

[0035] In this embodiment, the low-temperature water supply mechanism includes a first solar water supply unit, and the medium-temperature water supply mechanism includes a second solar water supply unit. When the external ambient light radiation exceeds the preset light radiation, the first and second solar water supply units can respectively generate a heat source of 40°C and a heat source of 60°C, making full use of solar energy, effectively reducing the heating energy consumption of the heat supply system, and achieving green heating. When the external ambient light radiation does not exceed the preset light radiation, the low-temperature heat pump mechanism and the medium-temperature heat pump mechanism are used to generate a heat source of 40°C and a heat source of 60°C, respectively, ensuring that the heat supply system can work normally on cloudy or rainy days, and improving the stability and reliability of the heat supply system during operation.

[0036] Further, please refer to Figure 1 The first solar water supply unit includes a photovoltaic thermal module 51 and a first delivery pump 52, which are electrically connected to the control device. The photovoltaic thermal module 51, the first delivery pump 52, and the first hot water storage tank 1 form a circulation loop. The low-temperature heat pump mechanism includes a low-temperature heat pump unit 53 and a second delivery pump 54, which are electrically connected to the control device. The low-temperature heat pump unit 53, the second delivery pump 54, and the first hot water storage tank 1 form a circulation loop.

[0037] In this embodiment, when the first solar water supply unit is used to prepare the heat source, the photovoltaic thermal module 51 heats the heat exchange medium. The heated heat exchange medium is transported to the first hot water storage tank 1 by the first transfer pump 52. The heat exchange medium is then returned to the photovoltaic thermal module 51 through the pipeline. When the low-temperature heat pump mechanism is used to prepare the heat source, the low-temperature heat pump unit 53 absorbs heat from the air. The water source in the first hot water storage tank 1 enters the low-temperature heat pump unit 53 for heat exchange and is then returned to the first hot water storage tank 1 by the second transfer pump 54.

[0038] Further, please refer to Figure 1The second solar water supply unit includes a fourth hot water storage tank 61 and a flat-plate collector 62, a third delivery pump 63, and a fourth delivery pump 64, all electrically connected to the control device. The flat-plate collector 62, the third delivery pump 63, and the fourth hot water storage tank 61 form a circulation loop. The output end of the fourth hot water storage tank 61 is connected to the input end of the second hot water storage tank 2 through the fourth delivery pump 64. The medium-temperature heat pump mechanism includes a medium-temperature heat pump unit 65, a fifth delivery pump 66, and a sixth delivery pump 67, all electrically connected to the control device. The first hot water storage tank 1, the fifth delivery pump 66, and the medium-temperature heat pump unit 65 form a circulation loop. The medium-temperature heat pump unit 65, the sixth delivery pump 67, and the second hot water storage tank 2 also form a circulation loop.

[0039] In this embodiment, when the second solar water supply unit is used to prepare the heat source, the flat plate collector 62 heats the heat exchange medium. The heated heat exchange medium is then transported to the fourth hot water storage tank 61 by the third transfer pump 63. After heat exchange, the heat exchange medium returns to the flat plate collector 62 through a pipeline. The heat source in the fourth hot water storage tank 61 is then transported to the second hot water storage tank 2 for storage by the fourth transfer pump 64. When the medium-temperature heat pump mechanism is used to prepare the heat source, the low-temperature heat exchange medium of the medium-temperature heat pump unit 65 enters the first hot water storage tank 1 through a pipeline to absorb heat. After heat absorption, the heat exchange medium returns to the medium-temperature heat pump unit 65 through the fifth transfer pump 66 to obtain heat from the low-temperature heat pump unit 53. The water source in the second hot water storage tank 2 enters the medium-temperature heat pump unit 65 through the sixth transfer pump 67, exchanges heat with the high-temperature heat exchange medium of the medium-temperature heat pump unit 65, and then returns to the second hot water storage tank 2 through a pipeline.

[0040] Further, please refer to Figure 1 The high-temperature heat pump mechanism includes a seventh delivery pump 71, an eighth delivery pump 72, and a high-temperature heat pump unit 73, which are electrically connected to the control device respectively. The second hot water storage tank 2, the seventh delivery pump 71, and the high-temperature heat pump unit 73 form a circulation loop. The high-temperature heat pump mechanism, the eighth delivery pump 72, and the third hot water storage tank 3 form a circulation loop.

[0041] In this embodiment, when a high-temperature heat pump mechanism is used to prepare the heat source, the low-temperature heat exchange medium of the high-temperature heat pump unit 73 enters the second hot water storage tank 2 through the pipeline to absorb heat. After absorbing heat, the heat exchange medium is returned to the high-temperature heat pump unit 73 through the seventh transfer pump 71 to obtain heat from the medium-temperature heat pump unit 65. The water source in the third hot water storage tank 3 enters the high-temperature heat pump unit 73 through the pipeline, exchanges heat with the high-temperature heat exchange medium of the high-temperature heat pump unit 73, and is then returned to the third hot water storage tank 3 through the eighth transfer pump 72.

[0042] Further, please refer to Figure 1The ultra-high temperature heat pump mechanism includes a ninth delivery pump 81 and an ultra-high temperature heat pump unit 82, which are electrically connected to the control device. The ultra-high temperature heat pump unit 82, the ninth delivery pump 81, and the third hot water storage tank 3 form a circulation loop. The input end of the ultra-high temperature heat pump mechanism is also used to connect to an external water source, and the output end of the ultra-high temperature heat pump mechanism is also connected to the steam storage tank 4.

[0043] In this embodiment, when an ultra-high temperature heat pump mechanism is used to prepare the heat source, the low temperature heat exchange medium of the ultra-high temperature heat pump unit 82 enters the third hot water storage tank 3 through the ninth transfer pump 81 to absorb heat. After absorbing heat, the heat exchange medium returns to the ultra-high temperature heat pump unit 82 through the pipeline to obtain heat from the high temperature heat pump unit 73. The ultra-high temperature heat pump unit 82 heats the input external water source, and the generated water vapor enters the steam storage tank 4 through the pipeline.

[0044] Furthermore, the low-temperature heat pump unit 53 includes a first compressor, a first evaporator, a first condenser, and a first expansion valve. The first compressor, the first evaporator, the first expansion valve, and the first condenser are connected end to end in sequence. The first condenser is used to absorb heat from the air, and the first evaporator is used to increase the temperature of the liquid in the first hot water storage tank 1. The first compressor is electrically connected to the control device.

[0045] In this embodiment, when the low-temperature heat pump unit 53 starts working, the low-temperature high-pressure liquid refrigerant is throttled by the first expansion valve and becomes a low-temperature low-pressure liquid refrigerant. It then enters the first condenser to evaporate and absorb heat, absorbing a large amount of heat from the air. After evaporation and heat absorption, the refrigerant enters the first compressor in gaseous form. After being compressed, it becomes a high-temperature high-pressure refrigerant. The compressed high-temperature high-pressure refrigerant enters the first evaporator and releases its heat to the cold water from the first hot water storage tank 1. The cold water is heated to 40°C and directly returned to the first hot water storage tank 1 for storage and use by users. After releasing heat, the refrigerant enters the first expansion valve in liquid form, where it is throttled and its pressure reduced. This cycle continues uninterrupted.

[0046] In this embodiment, the composition of the medium-temperature heat pump unit 65 and the high-temperature heat pump unit 73 is the same as that of the low-temperature heat pump unit 53, and the working principle of the medium-temperature heat pump unit 65 and the high-temperature heat pump unit 73 are similar to the working principle of the low-temperature heat pump unit 53.

[0047] Furthermore, the ultra-high temperature heat pump unit 82 includes a fourth compressor, a fourth evaporator, a fourth condenser, a fourth expansion valve, and a flash tank. The fourth compressor, the fourth evaporator, the fourth expansion valve, and the fourth condenser are connected end to end in sequence. The fourth condenser is used to extract heat from the third hot water storage tank 3. The input end of the fourth evaporator is also used to connect to an external water source. The output end of the fourth evaporator is also connected to the input end of the flash tank. The output end of the flash tank is connected to the steam storage tank 4.

[0048] In this embodiment, when the ultra-high temperature heat pump unit 82 starts working, the low-temperature, high-pressure liquid refrigerant is throttled by the fourth expansion valve and becomes a low-temperature, low-pressure liquid refrigerant. It then enters the fourth condenser to evaporate and absorb heat, absorbing a large amount of heat from the third hot water storage tank 3. After evaporation and heat absorption, the refrigerant enters the fourth compressor in gaseous form. After being compressed, it becomes a high-temperature, high-pressure refrigerant. The compressed high-temperature, high-pressure refrigerant enters the fourth evaporator and releases its heat to the external water source entering the fourth evaporator. The external water source is heated to a steam state and enters the flash tank. After gas-liquid separation, the steam enters the steam storage tank 4 for storage and use by the user. After releasing heat, the refrigerant enters the fourth expansion valve in liquid form, where it is throttled and its pressure reduced. This cycle continues uninterrupted.

[0049] Please see Figure 2 and Figure 3 This application also provides a control method for a multi-grade heat energy supply system, wherein the control method is used to implement the operation control of the multi-grade heat energy supply system as described above, and the control method includes the following steps:

[0050] 200. Obtain the ambient radiation intensity and adjust the working mode of the multi-grade heat energy supply system according to the ambient radiation intensity. The working mode includes a sunny day mode and a cloudy / rainy day mode.

[0051] In this embodiment, when the ambient radiation intensity is ≥400W / m2, the sunny day mode is executed; otherwise, the cloudy / rainy day mode is executed.

[0052] 300. When the working mode is sunny mode, the control device first controls the second solar water supply unit to start working. When the real-time temperature inside the second hot water storage tank 2 meets the preset second temperature requirement, the control device controls the first solar water supply unit to start working. When the real-time temperature inside the first hot water storage tank 1 meets the preset first temperature requirement, the control device controls the high-temperature heat pump mechanism to start working. When the real-time temperature of the third hot water storage tank 3 meets the preset third temperature requirement, the control device controls the ultra-high temperature heat pump mechanism to start working, so that the internal temperature of the steam storage tank 4 meets the preset fourth temperature requirement.

[0053] Specifically, when the operating mode is sunny, the third delivery pump 63 and the fourth delivery pump 64 are started to collect heat using flat plate collectors, generating hot water at 55-60°C and storing it in the second hot water storage tank 2 at 60°C, or providing a heat source for the high-temperature heat pump mechanism in the next stage. Then, the first delivery pump 52 is started to provide 40°C hot water to the first hot water storage tank 1 using photovoltaic thermal components 51, which can also provide a heat source for the medium-temperature heat pump mechanism in the next stage. When the real-time temperatures in the first hot water storage tank 1 and the second hot water storage tank 2 both meet the preset temperatures, the seventh delivery pump 71 and the eighth delivery pump 72 are started to start the high-temperature heat pump unit 73. When the water temperature in the third hot water storage tank 3 reaches 90°C, the ninth delivery pump 81 is started, and the ultra-high temperature heat pump unit 82 is started, simultaneously supplying heat to the ultra-high temperature heat pump. Unit 82 provides ambient temperature water. The ultra-high temperature heat pump system extracts heat from the third hot water storage tank 3 at 90℃, which heats the ambient temperature water and outputs 120℃ steam into the steam storage tank 4, which is then supplied to the steam demand side of the park. When the weather is sunny and the solar radiation intensity is high, the entire system can obtain 40℃ and 60℃ hot water free of charge using photovoltaic thermal modules 51 and flat plate collectors 62. The energy efficiency of the entire system in producing 120℃ steam is 2.1. The coefficient of performance (COP) of the heat pump in producing 90℃ hot water reaches 5. When the entire system provides the same weight of 40℃ hot water, 60℃ hot water, 90℃ hot water and 120℃ steam to the park in this operating mode, the comprehensive energy efficiency reaches 2.46, saving 72% of the heating cost compared to using an all-electric heating system.

[0054] 400. When the working mode is the rainy day mode, the control device first controls the low temperature heat pump mechanism to start working. When the real-time temperature inside the first hot water storage tank 1 meets the preset first temperature requirement, the control device controls the medium temperature heat pump mechanism to start working. When the real-time temperature inside the second hot water storage tank 2 meets the preset second temperature requirement, the control device controls the high temperature heat pump mechanism to start working. When the real-time temperature inside the third hot water storage tank 3 meets the preset third temperature requirement, the control device controls the ultra-high temperature heat pump mechanism to start working, so that the internal temperature of the steam storage tank 4 meets the preset fourth temperature requirement.

[0055] Specifically, when the operating mode is cloudy / rainy day mode, since the photovoltaic thermal module 51 and the flat plate collector 62 cannot obtain solar energy, the low-temperature heat pump unit 53 is started to obtain heat from the air to produce 40°C hot water to compensate for the inability of the solar energy utilization module to work in cloudy / rainy weather and ensure a stable heat supply for the entire park. First, the second transfer pump 54 is started and the low-temperature heat pump unit 53 is turned on. The low-temperature heat pump unit 53 obtains heat from the air to produce 40°C hot water. When the water temperature in the first hot water storage tank 1 reaches 40°C, the fifth transfer pump 66 and the sixth transfer pump 67 are started, followed by the medium-temperature heat pump unit 65. Hot water at 60℃ is generated. At this time, the low-temperature heat pump unit 53 continues to operate to continuously provide heat to the first hot water storage tank 1. When the water temperature in the second hot water storage tank 2 reaches 60℃, the seventh transfer pump 71 and the eighth transfer pump 72 are started, and the high-temperature heat pump unit 73 is started. When the water temperature in the third hot water storage tank 3 reaches 90℃, the ninth transfer pump 81 is started, and the ultra-high temperature heat pump unit 82 is started. At the same time, room temperature water is provided to the ultra-high temperature heat pump unit 82. The ultra-high temperature heat pump unit 82 extracts heat from the 90℃ hot water storage tank, which can heat the room temperature water and output 120℃ water vapor into the steam storage tank 4, and then supply it to the steam demand side of the park. The system extracts heat of corresponding grades from hot water storage tanks at 40℃, 60℃, and 90℃, and a steam tank at 120℃ to supply heat to the park, meeting the park's diverse heat source needs. During cloudy or rainy weather, the system achieves a COP of 1.5 for producing 120℃ steam, 2.0 for producing 90℃ hot water, 2.8 for producing 60℃ hot water, and 3.8 for producing 40℃ hot water. The overall energy efficiency of the system is 1.68, saving 58% in heating costs compared to an electric heating system.

[0056] In this embodiment, temperature sensors can be installed in the first hot water storage tank 1, the second hot water storage tank 2, the third hot water storage tank 3, and the steam storage tank 4 to monitor the internal ambient temperature. When the internal ambient temperature meets the preset temperature requirement, the control device controls the corresponding heat pump unit to switch to standby mode. When the internal ambient temperature is lower than the preset temperature requirement of a certain value, which can be 3°C, the control device controls the corresponding heat pump unit to start working and heating again.

[0057] Further, please refer to Figure 3 The step prior to obtaining the ambient radiation intensity includes:

[0058] 101. Obtain real-time time. When the real-time time is during the rest period, the control device controls the low-temperature heat pump mechanism to start working. When the real-time temperature inside the first hot water storage tank 1 meets the preset first temperature requirement, the control device controls the low-temperature heat pump mechanism to return to the standby state.

[0059] In this embodiment, rest and production times can be preset in the control device according to the daily working hours of the industrial park. For example, 7:00 to 18:00 can be set as production time and 18:01 to 6:59 can be set as rest time.

[0060] 102. When the real-time period is during production time, obtain the ambient radiation intensity.

[0061] In this embodiment, since the park needs to supply heat immediately when production activities begin the next day, and the flat plate collector and photovoltaic thermal module 51 cannot generate heat for the corresponding area immediately when the sun rises, it takes 2 hours of heat collection operation for the water temperature in the first hot water storage tank 1 to reach 40°C. Therefore, the rainy day operation mode must be activated at night to store heat and ensure the heating demand for the next day. In addition, nighttime heat storage can effectively utilize off-peak electricity, further reducing the operating energy consumption and operating costs of the heat supply system. The system's nighttime heat storage operation mode is the same as the rainy day operation mode. By filling the heat storage tanks of different grades, it can provide short-term heating for the park for 3 hours. After the production time is reached, the system will then determine whether to enter the sunny day mode or the rainy day operation mode based on the ambient radiation intensity.

[0062] It is understood that those skilled in the art can make equivalent substitutions or changes to the technical solution and inventive concept of the present invention, and all such changes or substitutions should fall within the protection scope of the present invention.

Claims

1. A multi-grade heat energy supply system, characterized in that, The system includes a first hot water storage tank, a second hot water storage tank, a third hot water storage tank, a steam storage tank, a control device, and a low-temperature water supply mechanism, a medium-temperature water supply mechanism, a high-temperature heat pump mechanism, and an ultra-high-temperature heat pump mechanism, all electrically connected to the control device. The low-temperature water supply mechanism, the first hot water storage tank, the medium-temperature water supply mechanism, the second hot water storage tank, the high-temperature heat pump mechanism, the third hot water storage tank, and the steam storage tank are connected in sequence. The temperature of the hot water stored in the first hot water storage tank, the second hot water storage tank, and the third hot water storage tank gradually increases. The low-temperature water supply mechanism includes a first solar water supply unit and a low-temperature heat pump mechanism, and the medium-temperature water supply mechanism includes a second solar water supply unit and a medium-temperature heat pump mechanism. The output ends of the first solar water supply unit and the low-temperature heat pump mechanism are respectively connected to the input end of the first hot water storage tank. The output end of the first hot water storage tank is connected to the input end of the second hot water storage tank through the medium-temperature heat pump mechanism. The output end of the second solar water supply unit is connected to the input end of the second hot water storage tank. The first solar water supply unit, the low-temperature heat pump mechanism, the second solar water supply unit, and the medium-temperature heat pump mechanism are respectively electrically connected to the control device. The high-temperature heat pump mechanism includes a seventh delivery pump, an eighth delivery pump, and a high-temperature heat pump unit, all electrically connected to the control device. The second hot water storage tank, the seventh delivery pump, and the high-temperature heat pump unit form a circulation loop. The high-temperature heat pump mechanism, the eighth delivery pump, and the third hot water storage tank also form a circulation loop. The ultra-high temperature heat pump mechanism includes a ninth delivery pump and an ultra-high temperature heat pump unit, which are electrically connected to the control device respectively. The ultra-high temperature heat pump unit, the ninth delivery pump, and the third hot water storage tank form a circulation loop. The input end of the ultra-high temperature heat pump mechanism is also used to connect to an external water source, and the output end of the ultra-high temperature heat pump mechanism is also connected to the steam storage tank.

2. The multi-grade heat energy supply system according to claim 1, characterized in that, The first solar water supply unit includes a photovoltaic thermal module and a first delivery pump, which are electrically connected to the control device. The photovoltaic thermal module, the first delivery pump, and the first hot water storage tank form a circulation loop. The low-temperature heat pump mechanism includes a low-temperature heat pump unit and a second delivery pump, which are electrically connected to the control device. The low-temperature heat pump unit, the second delivery pump, and the first hot water storage tank form a circulation loop.

3. The multi-grade heat energy supply system according to claim 1, characterized in that, The second solar water supply unit includes a fourth hot water storage tank, a flat-plate collector, a third delivery pump, and a fourth delivery pump, all electrically connected to the control device. The flat-plate collector, the third delivery pump, and the fourth hot water storage tank form a circulation loop. The output end of the fourth hot water storage tank is connected to the input end of the second hot water storage tank via the fourth delivery pump. The medium-temperature heat pump mechanism includes a medium-temperature heat pump unit, a fifth delivery pump, and a sixth delivery pump, all electrically connected to the control device. The first hot water storage tank, the fifth delivery pump, and the medium-temperature heat pump unit form a circulation loop. The medium-temperature heat pump unit, the sixth delivery pump, and the second hot water storage tank also form a circulation loop.

4. The multi-grade heat energy supply system according to claim 3, characterized in that, The low-temperature heat pump unit includes a first compressor, a first evaporator, a first condenser, and a first expansion valve. The first compressor, the first evaporator, the first expansion valve, and the first condenser are connected end to end in sequence. The first condenser is used to absorb heat from the air, and the first evaporator is used to increase the temperature of the liquid in the first hot water storage tank. The first compressor is electrically connected to the control device.

5. A multi-grade heat energy supply system according to claim 1, characterized in that, The ultra-high temperature heat pump unit includes a fourth compressor, a fourth evaporator, a fourth condenser, a fourth expansion valve, and a flash tank. The fourth compressor, fourth evaporator, fourth expansion valve, and fourth condenser are connected end to end in sequence. The fourth condenser is used to extract heat from the third hot water storage tank. The input end of the fourth evaporator is also used to connect to an external water source. The output end of the fourth evaporator is also connected to the input end of the flash tank. The output end of the flash tank is connected to the steam storage tank.

6. A control method for a multi-grade heat energy supply system, characterized in that, The control method is used to implement the operation control of the multi-grade heat energy supply system as described in any one of claims 2-5, and the control method includes the following steps: The ambient radiation intensity is obtained, and the working mode of the multi-grade heat energy supply system is adjusted according to the ambient radiation intensity. The working mode includes a sunny day mode and a cloudy / rainy day mode. When the working mode is sunny mode, the control device first controls the second solar water supply unit to start working. When the real-time temperature inside the second hot water storage tank meets the preset second temperature requirement, the control device controls the first solar water supply unit to start working. When the real-time temperature inside the first hot water storage tank meets the preset first temperature requirement, the control device controls the high-temperature heat pump mechanism to start working. When the real-time temperature inside the third hot water storage tank meets the preset third temperature requirement, the control device controls the ultra-high temperature heat pump mechanism to start working, so that the internal temperature of the steam storage tank meets the preset fourth temperature requirement. When the working mode is the rainy day mode, the control device first controls the low-temperature heat pump mechanism to start working. When the real-time temperature inside the first hot water storage tank meets the preset first temperature requirement, the control device controls the medium-temperature heat pump mechanism to start working. When the real-time temperature inside the second hot water storage tank meets the preset second temperature requirement, the control device controls the high-temperature heat pump mechanism to start working. When the real-time temperature inside the third hot water storage tank meets the preset third temperature requirement, the control device controls the ultra-high temperature heat pump mechanism to start working, so that the internal temperature of the steam storage tank meets the preset fourth temperature requirement.

7. The control method for a multi-grade heat energy supply system according to claim 6, characterized in that, The step prior to obtaining the ambient radiation intensity includes: The system acquires real-time time. When the real-time time is within the rest period, the control device controls the low-temperature heat pump mechanism to start working. When the real-time temperature inside the first hot water storage tank meets the preset first temperature requirement, the control device controls the low-temperature heat pump mechanism to return to standby mode. When the real-time period is during production time, the ambient radiation intensity is obtained.

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