Multi-energy combined supply system for collecting waste heat and waste electricity by taking sand as medium

Abstract

The invention relates to a multi-energy combined supply system which can collect waste heat and waste electricity in various forms, store the waste heat and the waste electricity in sand in a heat energy form, convert the waste heat and the waste electricity into high-quality heat energy and supply energy to the outside in four energy forms of cold, heat, electricity and steam. According to the invention, abandoned energy optimization, multiple purposes of waste energy, off-peak energy storage, cross-season energy storage and multi-energy complementation in cities can be realized. The system comprises a comprehensive energy subsystem, a sand energy storage subsystem, an energy supply subsystem and an intelligent control subsystem. The comprehensive energy subsystem comprises a power supply subsystem and a heat supply subsystem. The sand energy storage subsystem comprises a low-temperature heating subsystem, a low-temperature heat storage subsystem, a high-temperature heating subsystem, a high-temperature heat storage subsystem, a low-temperature heat exchange subsystem and a high-temperature heat exchange subsystem. The sand energy supply subsystem comprises a heat supply subsystem, a cold supply subsystem, a power supply subsystem and a steam supply subsystem. The intelligent control subsystem comprises a sensing subsystem, a network subsystem and an application subsystem.

Description

Technical Field

[0001] The present invention is an achievement in the field of new energy and energy storage functions. The invention uses sand as an energy storage medium, collects and converts the city's surplus electricity and waste heat into high-quality thermal energy, and then forms the ability to supply four types of energy: cold, heat, electricity, and steam, to serve production and life. The equipment system also has the peak-shaving function for thermal and power systems. The equipment system includes a comprehensive energy subsystem, a sand energy storage subsystem, an energy supply subsystem, and an intelligent control subsystem structure. Background Art

[0002] Power abandonment is a common behavior of distributed solar power generation systems and distributed wind power generation systems, especially in areas of my country where photovoltaic power generation and wind power generation are restricted. There are three reasons for this type of power abandonment. First, the region has excellent light or wind resources, or there is an oversupply of seasonal wind resources. A large amount of photovoltaic or wind power exceeds the needs of the region, city or enterprise, or exceeds the capacity of the power grid, and can only be abandoned. Similar power abandonment is very common in western my country. Second, the photovoltaic or wind power generated during holidays or shutdowns, or the wind power generated at night misses the production time. If there is no energy storage equipment or exceeds the capacity of the energy storage equipment, it can only be abandoned. Third, the installed capacity of photovoltaic or wind power originally exceeds the actual needs of the enterprise, and a large amount of surplus electricity cannot be consumed and can only be abandoned. Power abandonment in the latter two cases is very common in large factories.

[0003] Power abandonment also happens frequently in municipal power grids. Since large thermal power units also keep generating electricity at night, and the city's power consumption at night is much less than that during the day, the electricity can only be abandoned. In order to encourage people to use more nighttime electricity, the country often charges lower electricity prices at night than during the day, which is called valley electricity.

[0004] Waste heat, in industrial production, industrial waste heat is very common, such as waste heat from coal-fired workshops such as thermal power plants and steel plants, and waste heat from scalding pools in slaughterhouses or central kitchens and other food companies.

[0005] Abandoning heat is a common behavior of solar water heating equipment and photovoltaic thermal integrated products (PV / T). Such products generate a large amount of waste heat in the summer that cannot be digested. In order to prevent such products from generating a large amount of hot water in the summer, residents in southern cities often use shielding to shade the above equipment. Even in the north, solar water heating equipment will generate a large amount of waste heat in the summer that is discarded.

[0006] The above-mentioned abandoned electricity and heat, on the one hand, cause huge waste, and on the other hand, also limit the full play of the capabilities of distributed new energy equipment. In order to solve this problem, the present invention provides a flexible energy storage equipment system to achieve cross-season energy storage and peak-shaving energy storage, and by improving the quality of energy, it forms an energy supply capability of providing four energy forms: cold, heat, electricity, and steam. The present invention not only stores the abandoned energy, but also helps various new energy equipment to fully exert their effectiveness. The present invention can quickly open up the bottleneck of the development of distributed new energy and expand the market for new energy to the greatest extent. Summary of the invention

[0007] The purpose of the present invention is to provide a multi-energy combined supply system that can collect various forms of waste heat and waste electricity, store them in the form of thermal energy in sand, convert them into high-quality thermal energy, and then supply energy to the outside in the form of cold, heat, electricity and steam, so as to solve the problems raised in the above background technology.

[0008] The innovation of the present invention lies first in the use of sand as an energy storage medium. At present, the commonly used media for peak energy storage and waste energy and waste heat storage at home and abroad are water, molten salt and magnesium bricks. Sand has unique advantages over the above three substances. First, water is different from sand in that it turns into steam when it exceeds 100°C, and the container itself becomes a pressure vessel; second, water is easy to leak and has safety hazards. Compared with sand, the disadvantage of molten salt is that when the system temperature is lower than 190°C, the molten salt becomes solid, so it always maintains high temperature operation and the container operates under pressure. In addition, molten salt itself is a chemical product with high cost. In addition, the complete set of molten salt equipment is complex and difficult to miniaturize, so it is difficult to widely promote molten salt. The disadvantage of magnesium bricks compared with sand is that production and transportation require special sites and equipment, the heat storage container is troublesome to maintain, and the cost is much higher than sand. Compared with the above media, sand is simple to obtain, low cost, good heat transfer performance, melting point up to 2200°C, good fluidity, and high specific heat capacity, so sand has obvious comprehensive advantages as a heat storage medium.

[0009] The second innovation of this invention is to realize the combined supply of cold, heat, electricity and steam based on sand energy storage. The heat supply can serve industrial production, residential, office, commercial, agricultural facilities and other heating. The steam supply can serve industrial steam and industrial high-temperature hot water; at the same time, steam can be used to generate electricity and provide various types of production and domestic hot water through heat exchange. In addition, steam and high-temperature hot water can also be used as the driving force of absorption refrigeration. The above is the basic composition and function of the four-generation system.

[0010] The third innovation of the present invention is that the energy source of the sand is mainly waste electricity, waste heat, surplus electricity and waste heat in the city. The common equipment for absorbing and reusing waste heat is the absorption refrigerator, but it can only absorb waste heat and waste heat, not surplus electricity. It is also different from ordinary battery energy storage, which can only absorb electricity but not heat energy. The present invention absorbs both electricity and heat.

[0011] The present invention can realize the optimization of abandoned energy in the city, multiple uses of waste energy, off-peak energy storage, cross-season energy storage, and multi-energy complementarity.

[0012] The system structure of the present invention includes four subsystems, namely, a comprehensive energy subsystem, a sand energy storage subsystem, an energy supply subsystem, and an intelligent control subsystem.

[0013] The comprehensive energy subsystem includes a power supply subsystem and a heating subsystem.

[0014] The sand energy storage subsystem includes a low-temperature heating subsystem and a low-temperature heat storage subsystem, a high-temperature heating subsystem and a high-temperature heat storage subsystem, a low-temperature heat exchange subsystem and a high-temperature heat exchange subsystem.

[0015] The sand energy supply subsystem includes a heating pipeline, a cooling pipeline, a power supply pipeline, and a steam supply pipeline.

[0016] The intelligent control subsystem includes a perception subsystem, a network subsystem, and an application subsystem.

[0017] Preferably, the heating subsystem includes: solar water heating, industrial waste heat, biomass waste heat, and other waste heat, etc. The heating subsystem is originally responsible for providing a stable heat source for buildings, industrial production or agricultural facilities, and its unused part is used as the heat source of the system of the present invention.

[0018] Preferably, the power supply subsystem includes: solar photovoltaic, wind power, grid valley power and other abandoned power. The power supply subsystem is originally responsible for providing stable power for buildings, industrial power or agricultural facilities, and its unused part is used as the power source of the system of the present invention.

[0019] Preferably, the power supply subsystem includes solar photovoltaic, wind power, valley power, etc. This part of electricity, in the form of direct current and alternating current, is stored in the sand energy storage subsystem in the form of heat energy through electric heating as a source of high-temperature heat source.

[0020] Preferably, the photovoltaic power generation part of the power supply subsystem includes photovoltaic modules (PV) or combined heat and power solar panel modules (PV / T), grid-connected inverters, transformers, grid-connected power metering devices, user busbars, gateway power metering devices, etc.

[0021] Preferably, the wind power generation part includes a wind turbine generator set, a rectifier, a storage battery, and also includes a grid-connected inverter, a transformer, a grid-connected power metering device, a user bus, and a gateway power metering device that can be shared with the aforementioned photovoltaic system.

[0022] Preferably, the other abandoned power parts include a rectifier, a transformer, a grid-connected power metering device, a user bus, and a gateway power metering device.

[0023] Preferably, the valley electricity is cheap electricity in the power grid, which is connected to equipment such as transformers, grid-connected power metering devices, user buses, and gateway power metering devices to access the system of the present invention.

[0024] The heating subsystem, including solar thermal heat, industrial waste heat, biomass waste heat, and other waste heat, enters the sand energy storage subsystem and is provided to the sand low-temperature heat source.

[0025] Preferably, the solar thermal heat generating part includes solar thermal components such as combined heat and power solar panels (PV / T) or solar water heaters, thermal energy metering devices, buffer insulation water tanks, heat collection circulation pumps, heat pump units, and gateway thermal energy metering devices.

[0026] Preferably, industrial waste heat is the discarded heat generated in the production process of industrial enterprises, and the system includes a thermal energy metering device, a heat pump unit, and a gateway thermal energy metering device.

[0027] Preferably, the biomass waste heat part includes a biomass thermal energy metering device, a heat pump unit, and a gateway thermal energy metering device.

[0028] The sand energy storage subsystem is divided into three sequences, namely, low temperature sequence (heat storage part ≤ 100°C), high temperature sequence (heat storage part ≥ 500°C), and low and high temperature mixed sequence (heat storage part between 100°C and 500°C).

[0029] Preferably, the low temperature sequence uses the thermal subsystem as the main energy source and the electrical subsystem as an auxiliary.

[0030] Preferably, the high temperature sequence uses the electric power subsystem as the main energy source and the thermal subsystem as an auxiliary energy source.

[0031] Preferably, in actual operation, the low temperature sequence is from low temperature sand heating, low temperature sand heat storage to low temperature sand heating.

[0032] Preferably, high-temperature heat exchange can operate independently, that is, from high-temperature sand heating, high-temperature sand heat storage, to high-temperature sand heating, and can also assist in low-temperature heat exchange.

[0033] Preferably, the low temperature sequence and high temperature sequence of the sand energy storage subsystem can be independent in space. If the low temperature sequence and the high temperature sequence are combined in space, they will go from low temperature to high temperature and then drop to low temperature in time.

[0034] Preferably, when the system temperature exceeds 700°C, all heating equipment stops running, the high-temperature heating and heat dissipation device and the high-temperature sand heat storage and heat dissipation device are automatically turned on, and the heat exchange equipment continues to run until the temperature drops below 500°C.

[0035] The storage tank shell container of the sand energy storage subsystem must be installed with thermal insulation materials. There are three installation methods: internal insulation, external insulation, and internal and external mixed insulation.

[0036] Preferably, the maximum temperature that the container of the sand energy storage subsystem can withstand is controlled within 900°C.

[0037] Preferably, the inside of the container for high-temperature sand heating, low-temperature sand heating, low-temperature sand heating, and low- and high-temperature mixed sand heating uses metal pipes as heat exchange pipes and heat transfer oil as the heat medium.

[0038] Preferably, when the sand energy storage subsystem absorbs energy from the outside and stores energy, the heat transfer oil in the low-temperature sand heating and low-temperature mixed heating transfers heat to the sand through the metal pipe wall.

[0039] Preferably, when the energy storage subsystem releases energy, the heat stored in the sand in the low-temperature sand heating and the high-temperature sand heating is transferred to the heat transfer oil through the metal pipe wall.

[0040] An electric heating device is used inside the metal container of the sand energy storage subsystem as a tool for converting electricity into heat.

[0041] Preferably, electric heating devices are present in the high temperature sand heating area and the low and high temperature mixed sand heating area.

[0042] The tailing sand in the high-temperature sand heating area is transferred to the high-temperature sand heat dissipation area. After the high-temperature sand dissipates heat, it passes through the conveying equipment and enters the sand heating area again.

[0043] The sand in the high-temperature sand heat storage area and the low-temperature sand heat storage area has a high temperature and generally cannot be discharged directly. However, if an emergency occurs, it can be transferred to the high-temperature sand heat dissipation area. After the high-temperature sand dissipates heat, it passes through the conveying equipment and enters the sand heating area again.

[0044] The tailings in the high-temperature sand heating area can be transferred to the low-temperature sand heating area because the temperature is still relatively high.

[0045] The tailings sand in the low-temperature sand heating area can enter the low-temperature sand heat dissipation area and then be transferred to the sand heating area for reuse.

[0046] The setting, use and safety management principles, mechanisms and processes of the sand heat dissipation zone are all within the scope of protection of the present invention.

[0047] The heating pipeline includes a low-temperature heating pipeline and a high-temperature heating pipeline. The heat exchange carrier is heat transfer oil.

[0048] Preferably, the heat supplied by the low-temperature sand is transferred to the external heat-demanding system in the low-temperature heat exchange unit.

[0049] Preferably, the low-temperature heat exchanger generates low-temperature hot water (≤100°C) to directly provide heat for industrial production and building heating, or for industrial production and residential hot water, and can also provide a heat source for heating agricultural facilities or other heat needs.

[0050] Preferably, the heating pipeline includes equipment such as a flow meter, a thermometer, a water pump, and a pressure gauge.

[0051] The cooling pipeline is after the low temperature heat exchange unit or the steam heat exchange unit obtains high temperature hot water or steam, and then enters the absorption refrigerator, thereby generating cold energy and supplying it to the external cooling demand system.

[0052] Preferably, the cooling pipeline is a low-temperature heat exchanger or a high-temperature heat exchanger, forming hot water above 65°C or high-temperature steam, and providing cold water at 4 to 13°C through an absorption refrigerator to provide cooling for industrial production, building air conditioning, agricultural facilities, etc.

[0053] Preferably, the cooling pipeline includes equipment such as a flow meter, a thermometer, a water pump, and a pressure gauge.

[0054] The steam supply pipeline is used to form a high-temperature water-steam mixture (≥100°C) or steam in the steam heat exchange unit.

[0055] The steam is directly supplied to the external steam demand system.

[0056] Preferably, after the steam is condensed, it is connected to a low-temperature heat exchange unit or a steam heat exchange unit through a loop.

[0057] Preferably, the steam pipeline includes equipment such as a flow meter, a thermometer, a pressure gauge, and a steam pump.

[0058] The power supply pipeline is used to generate high-temperature steam in the steam heat exchange unit, and the steam is used to drive the steam turbine to generate electricity.

[0059] Preferably, the power supply circuit includes equipment such as an ammeter, a voltmeter, a transformer, and switchgear.

[0060] Preferably, the power supply pipeline can cooperate with the power grid to perform deep peak regulation, and can also be used as an emergency power supply.

[0061] The sensing subsystem includes thermometers, pressure gauges, flow meters, electric meters, water meters, barometers, calorimeters and other metering equipment.

[0062] Preferably, all types of power supplies supplying power to the system should be equipped with ammeters to convert AC power into DC power.

[0063] Preferably, each type of heat source supplying heat to the system should be equipped with a temperature sensor and a pressure sensor.

[0064] Preferably, each subsystem should be equipped with a temperature sensor and a pressure sensor. Sand flow meters should be installed from sand heating to sand heat storage to sand heating.

[0065] The network subsystem includes dedicated network, mobile network, heterogeneous network integration, remote control, resource and storage management, data cleaning, heterogeneity, analysis, presentation and processing systems.

[0066] The intelligent control subsystem includes valves, switch stations, inverters, junction boxes, voltage stabilizers, water tanks, and automatic control equipment for sand energy storage.

[0067] Preferably, the entire process of sand heating, sand heat storage, and sand heat supply can realize automatic feeding and discharging processing according to temperature and heat, and can be remotely controlled.

[0068] Preferably, each process of steam supply, heating, electricity supply and cooling supply can be automatically opened and closed and flow and energy metered according to user orders, and can be remotely controlled.

[0069] Preferably, through an intelligent control system, the storage of waste heat and waste electricity can be automatically completed and remotely controlled within the system of the present invention.

[0070] Preferably, the energy supply subsystem, all thermal equipment, steam equipment, and refrigeration equipment should be equipped with temperature sensors and intelligent flow control devices. All electrical equipment should be equipped with smart meters, voltage stabilizing equipment, and intelligent switching devices.

[0071] Each system described in the present invention, including the water pump, heat pump, electric heater, one-way control valve, intelligent flow meter, intelligent energy meter, intelligent cooling valve, etc., should have remote control energy supply.

[0072] The installation location, type, functional integration and energy supply combination of each device described in the present invention are all within the protection scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0074] Attached Figure 1 The subsystem planning diagram of the present invention;

[0075] Attached Figure 2 Subsystem planning diagram of the present invention;

[0076] Attached Figure 3 The subsystem composition diagram of the present invention;

[0077] Attached Figure 4System principle diagram of the present invention. DETAILED DESCRIPTION

[0078] It should be noted that, in the absence of conflict, the features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0079] The described embodiments are only a part of the present application, not all embodiments. Based on the embodiments in the present application, other embodiments obtained by those skilled in the art without creative work should all fall within the scope of protection of the present application.

[0080] Example 1

[0081] Solar water heating equipment produces hot water during the day.

[0082] If the hot water temperature is low due to factors such as low sunlight intensity or low external ambient temperature, it can be heated to the set temperature using electric heating equipment, and then the temperature can be raised to the set temperature of the low-temperature sand heating zone through a heat pump.

[0083] The heat medium in this part is water, which acts as a heat carrier in the heat exchanger to exchange heat with the heat transfer oil in the low-temperature sand heating area.

[0084] The heat transfer oil transfers heat to the low-temperature sand heating area, and when the sand temperature reaches 55℃~95℃, it is transferred to the low-temperature sand heat storage area.

[0085] The sand heat storage area has excellent thermal insulation properties and can store heat across seasons.

[0086] When heat needs to be exported, this part of the sand is transferred to the low-temperature sand heating area.

[0087] The low-temperature sand heating area exchanges heat with the water in the low-temperature heat exchange unit through the heat transfer oil pipeline. The water after heat exchange can be directly supplied to the external heating system, or it can provide cooling capacity for the external cooling system through the refrigerator.

[0088] If the water supply temperature of the low-temperature heat exchanger unit does not meet the temperature requirements of the external heat demand system or refrigerator, the temperature can be further increased by adding a heat pump or electric heating equipment.

[0089] The above-mentioned low-temperature sand heating, low-temperature sand heat storage, low-temperature sand heating based on solar water heating equipment, as well as the process and method of forming a heating subsystem and a cooling subsystem are also applicable to industrial waste heat and biomass waste heat, or other forms of heat sources.

[0090] In the embodiment 1, the whole process, principle and method of collecting waste heat by using sand as a medium and forming heating and cooling capabilities are all within the protection scope of the present invention.

[0091] Example 2

[0092] The solar photovoltaic equipment is connected to the electric heating equipment in the high-temperature sand heating area through inverters, junction boxes and other equipment, and converted into thermal energy to gradually heat the sand in the high-temperature sand heating area. After this part of the sand is heated to the ideal temperature (generally between 100℃ and 590℃), it is transferred to the high-temperature sand heat storage area.

[0093] The high-temperature sand heat storage area of ​​the present invention has excellent thermal insulation performance and can realize cross-seasonal energy storage.

[0094] In the high-temperature sand heating area and the high-temperature sand heat storage area, when the temperature reaches the warning temperature, the automatic heat dissipation valve of the heating area and the automatic heat dissipation valve of the high-temperature sand heat storage area will be automatically opened.

[0095] When the system needs external functions, the sand in the high-temperature sand heat storage area is transferred to the high-temperature sand heating area.

[0096] In the high-temperature sand heating area, heat is transferred to the water or steam in the steam heat exchanger through heat transfer oil.

[0097] The steam in the steam heat exchanger supplies energy to the outside in two ways. One is to directly provide it to the external steam demand system, and the other is to drive the steam turbine generator to generate electricity to provide electricity to the external power demand system.

[0098] When the steam heat exchanger supplies steam to the outside, the steam can also enter the refrigerator to output cold air to the outside.

[0099] The steam heat exchanger drives the steam turbine generator to generate electricity, and can also return it to the high-temperature sand heating area or the low-temperature and high-temperature sand mixed heating area.

[0100] The above process of high-temperature sand heating, low-temperature sand mixed heating, high-temperature sand heat storage, low-temperature sand mixed heat storage, and high-temperature sand heating based on solar photovoltaics, and then passing through a steam heat exchange unit to form a steam subsystem and a power supply subsystem, is also applicable to wind power generation, valley electricity in municipal power grids, and other surplus electricity.

[0101] In the embodiment 2, the whole process, principle and method of collecting surplus electricity by using sand as a medium and converting it into high-quality thermal energy, thereby forming the steam supply, cooling supply and power supply capability, are all within the protection scope of the present invention.

[0102] Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. For example, the sand heating area is first heated by low-temperature heat transfer oil, then heated to high temperature by electric heating equipment, and then the high-temperature sand is transferred to the high-temperature sand heat storage area. This mixed heating mode also falls within the scope of protection of this patent.

[0103] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field and related fields without creative work should fall within the scope of protection of the present invention. Structures, devices and operating methods not specifically described and explained in the present invention shall be implemented according to conventional means in the field unless otherwise specified and limited.

Claims

1. A new system that uses sand as a heat storage medium to collect various forms of waste heat and electricity in the city, converts it into high-quality thermal energy, and then supplies energy to the outside in four forms: cold, heat, electricity, and steam. The system consists of: Comprehensive energy subsystem (1), sand energy storage subsystem (2), energy supply subsystem (3), and intelligent control subsystem (4).

2. The comprehensive energy subsystem (1) according to claim 1 comprises a heating subsystem (7) and a power supply subsystem (8). The heating subsystem (7) collects urban solar heat (26), industrial waste heat (27), biomass heat (28), other waste heat (29), etc. The power supply subsystem (8) collects solar power (32), wind power (31), other waste power (33) and grid valley power (30).

3. The solar power (32) part of the power supply subsystem (8) according to claim 2 includes photovoltaic modules (PV) or combined heat and power solar panel modules (PV / T), grid-connected inverters, transformers, grid-connected power metering devices, user buses, gateway power metering devices, etc. The wind power generation part (31) includes wind turbine generator sets, rectifiers, and storage batteries, and also includes grid-connected inverters, transformers, grid-connected power metering devices, user buses, and gateway power metering devices that can be shared with the aforementioned photovoltaic power generation system. The other surplus power (33) includes generator sets, rectifiers, transformers, grid-connected power metering devices, user buses, and gateway power metering devices. The valley power (30) refers to the power in the power grid during the cheapest time period. The transformers, grid-connected power metering devices, user buses, and gateway power metering devices are shared with the aforementioned photovoltaic system, wind power system, and biomass power system.

4. The solar water heating part (26) of the heating subsystem (7) according to claim 2 comprises a solar thermal component such as a combined heat and power solar panel (PV / T) or a solar water heater, a heat metering device, a buffer insulation water tank, a heat collection circulation pump, a heat pump unit, and a gateway heat metering device. The industrial waste heat part (27) of the heating subsystem (7) comprises a heat metering device, a heat pump unit, and a gateway heat metering device. The biomass heat (28) part of the heating subsystem (7) comprises a biomass waste heat metering device, a heat pump unit, and a gateway heat metering device.

5. According to claim 1, the sand energy storage subsystem (2) comprises three parts: a sand heating subsystem (9), a sand heat storage subsystem (10), and a sand heating subsystem (11). Each part also has three types: low temperature sequence (≤100°C) (low temperature heating area 34, low temperature heat storage area 35, low temperature heating area 36), high temperature sequence (≥100°C) (high temperature heating area 37, high temperature heat storage area 38, high temperature heating area 39), and low and high temperature mixed subsystem (low and high temperature mixed heating area 53, low and high temperature mixed heat storage 51).

6. According to claim 5, the sand energy storage subsystem has a metal shell with a heat-insulating layer installed. The metal pipe inside the container is used as a heat exchange pipe, and the heat transfer oil is used as a heat medium to perform heat exchange with the heat exchanger (54), the low-temperature heat exchanger (42), and the steam heat exchanger (43).

7. According to claim 5, in the sand heating subsystem (9), high temperature sand heating (34) and low and high temperature mixed heating (53) are achieved by high temperature heating through electric heating equipment, and the electricity comes from the power supply subsystem (8).

8. The energy supply subsystem (3) according to claim 1 comprises a heating pipeline (13), a cooling pipeline (14), a steam supply pipeline (15) and a power supply pipeline (16).

9. The intelligent control subsystem (4) according to claim 1 comprises a sensing subsystem, a network transmission subsystem, and a remote intelligent control subsystem. The sensing subsystem comprises thermometers, pressure gauges, flow meters, electric meters, water meters, barometers, calorimeters, level meters and other metering devices. The network subsystem comprises dedicated networks, mobile networks, heterogeneous network integration, resource and storage management, data processing and storage systems and other systems. The remote intelligent control application subsystem comprises valves, switches, monitoring equipment, and has functions such as equipment abnormality alarm processing, log management, security management, statistical analysis reports and other functions.

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