Waste heat recovery power generation zero-carbon energy system

Abstract

This invention provides a waste heat recovery power generation zero-carbon energy system. This system primarily utilizes thermal energy, the chimney effect, and wind power generation technology to recover waste heat and generate zero-carbon energy. The system mainly consists of thermal energy, wind turbine ducts, a wind turbine generator, and an energy storage device. The wind turbine ducts generate wind power, which drives the wind turbine generator to produce electricity. Waste heat increases the temperature difference; the greater the temperature difference, the greater the wind power generated by the wind turbine duct, and the more electricity is generated. Both waste heat and solar energy can increase the temperature difference and enhance wind power efficiency. The energy storage equipment can expand the application scope of the waste heat power system.

Description

Technical Field

[0001] This invention relates to green energy; in particular to waste heat recovery and wind power generation. Background Technology

[0002] Industrial production, agricultural product processing, and food processing all require heat energy, generating large amounts of high, medium, and low-temperature waste heat. While a significant portion of high-temperature waste heat is recovered and utilized, low-temperature waste heat, despite its substantial volume, is almost impossible to recover and utilize. This is because no effective technology has yet been developed to address the problem of recovering and utilizing low-grade heat energy. Industrial waste heat is essentially unused heat energy from the production process, belonging to secondary energy sources. Its recovery and utilization can significantly save energy and reduce carbon emissions. Low-carbon production and living are necessities for human development. To address these issues, this invention provides a novel waste heat and residual heat recovery and power generation system; it solves the waste heat recovery problem while generating green energy, providing technology for low-carbon production and living. The chimney effect generates power that accelerates airflow, which can drive wind turbines to generate electricity. This electricity can then be stored using energy storage technology. The stored energy can provide zero-carbon energy to users in different regions and at different times; for example, it can be stored in spring, summer, and autumn for winter heating; or stored in location A and transported to location B for use. This constructs a zero-carbon technology system combining waste heat, wind power, and energy storage. This system can not only solve various practical problems of waste heat recovery, but also produce zero-carbon energy, realize green production and living, and reduce carbon emissions.

[0003] The passive stack effect utilizes the principle of rising hot air and replenishing it with cold air to create a continuous upward airflow. The greater the temperature difference and the higher the vertical channel, the stronger the airflow and the greater the wind force (wind speed reaches 4-6 m / s when the temperature difference is 10-15℃). The stronger the wind, the higher the wind power generation efficiency. In recent years, wind turbines of various shapes have emerged, ranging from large to tiny turbines the size of a fist. The starting wind speed for wind turbines is 2-3 m / s. The passive stack effect promotes airflow and ventilation, while also accelerating cooling and improving wind power generation efficiency. Combining wind power generation technology, a vertical stack structure and heat source can enhance wind speed and wind power generation efficiency, creating a stack-based power system.

[0004] Airflow intensity generated by the chimney effect N It can be expressed as follows: (1) A 1. A 2 represents the inlet and outlet area of ​​the wind. H The height difference between the air inlet and outlet. t n and tw These refer to the temperatures of the inside and outside air, respectively.

[0005] Therefore, the strength of the wind is directly proportional to the length of the wind duct, the size of the air inlet and outlet, and the temperature difference between the air at the inlet and outlet.

[0006] airflow velocity generated by the chimney effect v It can be calculated using the following formula: (2) g Gravitational acceleration (9.81 m / s²) 2 ) H Chimney height (m) T n Temperature of hot air inside the chimney (K) T w Ambient temperature (K) It is evident that the taller the chimney, the greater the temperature difference between the inside and outside of the chimney, and the higher the airflow speed.

[0007] Based on the principle of wind energy conversion, the formula for calculating the power of a wind turbine is (WIND ENERGY CONVERSIONTHEORY, BETZ EQUATION. M. Ragheb. 2021-02-23): (3) P This is the output power of the wind turbine (unit: watt, W). ρ Air density (unit: kilograms per cubic meter, kg / m³) 3 ); A It is the swept area of ​​the wind turbine (unit: square meters, m). 2 For horizontal axis wind turbines, ( R (where the blade radius is 1). For vertical axis wind turbines, ( R Where is the blade radius. H (for blade height) v Wind speed (unit: meters per second, m / s); Cp It is the wind energy utilization coefficient, which represents the wind energy conversion efficiency. The theoretical limit is 0.593 (Bates limit), and it is usually between 0.25 and 0.47.

[0008] This formula shows that the power of a wind turbine is directly proportional to the air density, the swept area of ​​the rotor, and the cube of the wind speed. If the wind speed increases by 10%, the wind power will increase by approximately 33.1% (1.1...). 3 = 1.33); if the wind speed doubles, the available wind energy power will increase to 8 times the original (2 3 = 8).

[0009] It is evident that the longer the wind turbine duct, the greater the temperature difference between the inside and outside of the duct, the stronger the airflow accelerates upwards along the vertical channel, resulting in stronger winds and more electricity generated. In other words, a smaller diameter at the top and a larger diameter at the bottom of the duct creates an acceleration channel (Venturi effect), further increasing airflow speed. Both temperature difference and the duct itself can affect the strength of the wind and the amount of electricity generated. Summary of the Invention

[0010] Based on the chimney effect and the principle of wind power generation, this invention provides a novel waste heat recovery and zero-carbon energy technology system, namely, a chimney effect power system. It utilizes waste heat to enhance the chimney effect, generates green electricity using wind power, and then uses energy storage technology to store the electricity generated by wind power, thereby constructing a zero-carbon energy system for waste heat recovery. Waste heat + wind power generation + energy storage = zero-carbon energy Waste heat + wind power = zero-carbon energy The main technical principles involved in this invention include the chimney effect, wind power generation, and energy storage; it is an integration of multiple disciplines and technologies.

[0011] Wind turbine ducts generate a chimney effect. Each end of the duct has an inlet and an outlet, and the area of ​​the inlet and outlet, as well as the length of the duct, affects the wind strength and power generation efficiency. Furthermore, the greater the temperature difference between the inlet and outlet, the stronger the wind. Therefore, this invention proposes utilizing waste heat to raise the temperature at the duct outlet, increasing the temperature difference between the inlet and outlet, and enhancing wind power generation efficiency. This provides a novel waste heat recovery technology and innovates a waste heat-electricity system technology.

[0012] On the other hand, energy storage technologies include battery energy storage, phase change energy storage, sensible thermal energy storage, chemical energy storage, mechanical energy storage, compressed air energy storage, thermal energy storage, and reservoir energy storage. Chemical thermal energy storage technology, among others, is a long-term energy storage technology and also a cross-seasonal energy storage technology, capable of storing energy in summer and using it in winter (CN201910167308.8 Medium-temperature cross-seasonal thermal energy storage materials). The stored energy can be provided to users in both electrical and thermal forms. For example... Figure 1As shown: the air inlet 1 is at the bottom of the wind duct 2, the air outlet 3 is at the top of the wind duct 2, and the wind turbine 4 is above the air outlet 3; the wind turbine 4 is connected to the generator 5, and the electricity generated by the generator 5 is transmitted to the energy storage device 7 via cable 6. The energy stored in the energy storage device 7 provides zero-carbon energy to the user 8 when appropriate; the heat energy 9 is located at the bottom of the wind duct 2 and heats the air. The air inlet 1 is connected to the hot air generated by the waste heat source. The hot air accelerates and rises in the wind duct 2 to generate a high-speed airflow. The high-speed airflow drives the wind turbine 4 to rotate, and the wind turbine 4 drives the generator 5 to rotate to generate electricity; the electricity is transmitted to the energy storage device 7 via cable 6, and the electricity is stored by the energy storage device 7.

[0013] Furthermore, the aforementioned chimney effect power system may or may not include an energy storage system.

[0014] Furthermore, in the aforementioned chimney effect power system, the wind turbine can be placed at the top of the wind duct or in the middle of the wind duct. The wind power in the duct drives the wind turbine's rotor to rotate, thereby driving the generator to generate electricity. One wind duct can drive one wind turbine to generate electricity, or it can drive two or more wind turbines to generate electricity.

[0015] Furthermore, in the aforementioned chimney effect power system, the wind turbine blades involved are preferably selected as low-wind-speed-starting blades to adapt to the stable airflow of the chimney effect.

[0016] Furthermore, in the aforementioned chimney effect power system, the generators involved are preferentially selected as high-efficiency low-speed generators (such as permanent magnet synchronous generators) to directly convert mechanical energy into electrical energy.

[0017] Furthermore, the wind duct can be of various shapes, including cylindrical and square; the wind duct can have one or more air inlets; and the wind duct can have one or more air outlets.

[0018] Furthermore, in the aforementioned chimney effect power system, the length of the wind turbine duct is determined by actual needs, the size of the air inlet and outlet is calculated based on power generation and air flow, and the cross-sectional dimensions of the duct are determined by calculation and needs.

[0019] Furthermore, the aforementioned chimney effect power system, involving wind ducts, including flow regulating valves that regulate airflow, can also be completely shut off.

[0020] Furthermore, regarding the aforementioned wind duct, the height determines the airflow speed; the higher the duct, the more pronounced the chimney effect. For example, a 50-meter-high chimney, with a temperature difference of 10... o At temperature C, the airflow velocity can reach 4-6 m / s.

[0021] Furthermore, the wind duct has a smaller diameter at the top and a larger diameter at the bottom, forming an acceleration channel (Venturi effect) to further increase the airflow speed.

[0022] Furthermore, the aforementioned chimney effect power system involves a heat source system including solar heating, with solar energy including both photovoltaic and solar thermal energy systems to enhance the temperature difference and wind speed of the wind turbine duct.

[0023] Furthermore, the heat source involved in the chimney effect power system includes thermal energy byproducts generated by the photovoltaic system.

[0024] Furthermore, the aforementioned chimney effect power system involves heat sources including various high, medium, and low temperature heat sources, as well as industrial waste heat and residual heat. Examples include various waste heat and residual heat from steel mills, glass factories, cement plants, brick factories, ceramic factories, power plants, data centers, and ventilation systems.

[0025] Furthermore, the aforementioned chimney effect power system involves heat sources including the heat energy from biomass combustion.

[0026] Furthermore, the aforementioned chimney effect power system involves heat sources including various flue gas recovery systems, various ventilation systems, and various boiler systems.

[0027] Furthermore, in the aforementioned chimney effect power system, the liquid heat source involved can utilize a liquid-air heat exchanger to enhance the chimney effect and power generation efficiency.

[0028] Furthermore, the aforementioned chimney effect power system can be used in conjunction with a ventilation system to generate electricity again using the wind power of the ventilation system.

[0029] Furthermore, the energy storage device is used to store the electricity generated by the wind turbine. The energy storage device is selected from battery energy storage, phase change energy storage, sensible heat (molten salt) energy storage, chemical energy storage, mechanical energy storage, compressed air energy storage, ammonia energy storage, hydrogen energy storage, chemical thermal energy storage, and reservoir energy storage, etc. Compressed air energy storage, ammonia energy storage, hydrogen energy storage, batteries, chemical thermal energy storage, and chemical energy storage technologies are long-term energy storage technologies and devices.

[0030] Furthermore, the energy storage technology equipment is preferably a long-term energy storage technology equipment, but sensible heat energy storage equipment and latent heat energy storage equipment can also be selected.

[0031] Furthermore, the energy storage technology equipment can use hydrogen energy storage, that is, using the electricity generated by the wind turbine to electrolyze water to produce hydrogen, thus completing energy storage, and the hydrogen is burned to provide heat energy.

[0032] Furthermore, the energy storage technology device described above can both store and release energy; the energy storage device can supply thermal energy as well as electrical energy.

[0033] Furthermore, the aforementioned chimney effect power system also includes an intelligent control system to ensure the safe and efficient operation of the system.

[0034] The novelty of this invention lies in utilizing the chimney effect, wind power generation, and energy storage technology to achieve waste heat recovery and zero-carbon energy generation. Energy storage technology addresses the issues of wind power storage and spatial and temporal differences between energy sources and users, representing an integration of multiple disciplines. The technical advantages of this invention include: ① Low-wind-speed power generation: generating air and electricity by heating it with various waste heat sources and solar heat under windless conditions; ② High stability: the chimney effect is less affected by weather, allowing for continuous generation of green energy; ③ Zero-carbon energy and waste energy regeneration: generating new energy sources using solar energy or industrial waste heat and waste energy, reducing carbon emissions; ④ Abundant application scenarios.

[0035] This invention covers a wide range of applications, such as: ① using the chimney effect to generate electricity in sunny areas such as deserts and plateaus; ② using waste heat and waste energy from factories to drive the chimney effect to generate electricity; ③ installing small chimney effect wind turbines on building roofs to provide auxiliary power supply, ventilation, and cooling; and ④ adding wind turbines to ventilation systems to generate electricity.

[0036] The scientific principles and beneficial effects of this invention are as follows: The waste heat chimney effect power system involved in this invention belongs to the green energy system, integrating technologies such as thermal energy utilization, chimney effect, mechanical design, wind power generation, and intelligent control; furthermore, it utilizes energy storage technology to store the electrical energy generated by the wind turbine, enhancing the system's practicality and application scope. This technology system can not only recover various types of waste heat, but also combine solar energy, biomass thermal energy, wind power from ventilation systems, and wind power technology to generate green energy. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the chimney-powered zero-carbon energy system of the present invention.

[0038] As shown in the figure: 1. Air inlet; 2. Air duct; 3. Air outlet; 4. Wind turbine; 5. Generator; 6. Cable; 7. Energy storage device; 8. User; 9. Thermal energy. Detailed Implementation

[0039] In practical implementation, the blades of the wind turbine are installed inside the wind duct or at the wind outlet, enabling the wind to efficiently drive the wind turbine to rotate. The rotation of the wind turbine drives the generator to generate electricity. The generated electricity can be used directly or stored in an energy storage device. The stored energy is released for user use when needed. To make the content of this invention clearer and more understandable, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings.

[0040] Example 1, Combined with appendix Figure 1 In specific implementations of this invention: The thermal power plant generates a large amount of wastewater at about 60 degrees Celsius every day. This wastewater enters a finned heat exchanger, where it exchanges heat with the air to generate hot air that enters a 10-meter-high duct. A 3 kW wind turbine is installed at the top of the duct, generating about 2.8 kW of electricity per hour.

[0041] Example 2, Combined with appendix Figure 1 In specific implementations of this invention: The blast furnace flue gas from the steel plant is discharged at a temperature of about 100 degrees Celsius after heat recovery through a waste heat boiler. This low-temperature exhaust gas directly enters a wind turbine duct about 8 meters high. Two 5 kW wind turbines are installed at the top of the wind turbine duct, with an airflow speed of about 10 m / s; it generates about 9.8 kW of electricity per hour.

[0042] Example 3, Combined with appendix Figure 1 In specific implementations of this invention: When used in conjunction with the subway ventilation system, a 1 kW wind turbine is installed at the air outlet of each ventilation system to generate electricity for lighting.

[0043] Example 4, Combined with appendix Figure 1 In specific implementations of this invention: The hot air at the kiln opening of the brick kiln is approximately 50 degrees Celsius and is connected to a wind turbine duct. A wind turbine at the top of the duct generates approximately 2.6 kW of electricity per hour. The bricks exiting the kiln are approximately 180 degrees Celsius, and the resulting hot air is circulated into the wind turbine duct. One wind turbine is installed in the middle and another at the top of the duct, generating a total of approximately 7.5 kW of electricity per hour. This electricity is stored using energy storage technology, and the stored energy is used to generate steam.

[0044] Example 5, Combined with appendix Figure 1 In specific implementations of this invention: Temperatures in greenhouses can reach 50 degrees Celsius in summer, requiring cooling. A 10-acre greenhouse equipped with six vertical ventilation ducts and a matching wind turbine generates approximately 55 kW of electricity daily during summer sunshine hours, lowering the internal temperature to around 30 degrees Celsius, sufficient for plant growth. This electricity is then stored across seasons using chemical thermal energy storage technology, with the stored energy used for winter heating.

[0045] Example 6, Combined with appendix Figure 1 In specific implementations of this invention: The photovoltaic equipment generates hot water at approximately 60 degrees Celsius. This hot water is then exchanged with a finned heat exchanger to produce hot air. The hot air is then introduced into a vertical wind turbine duct, generating an airflow of approximately 10 m / s. During periods of sunshine, the wind turbine generates approximately 30 kW of electricity per day.

[0046] The above embodiments are only used to illustrate the technical features and applications of the present invention, and are not intended to limit the scope of the present invention. Any technical modifications or substitutions made within the spirit and scope of the technical solutions and claims involved in the present invention shall fall within the technical scope of the present invention.

Claims

1. A waste heat recovery and power generation zero-carbon energy system, characterized in that: the zero-carbon energy system mainly consists of thermal energy, wind power ducts, wind turbines, and energy storage devices; the wind power ducts generate wind power, the wind power drives the wind turbines to generate electricity, the thermal energy enhances the wind power, and the energy storage devices store electricity for backup.

2. The zero-carbon energy system according to claim 1, characterized in that: the zero-carbon energy system mainly consists of thermal energy, wind power ducts and wind turbines; the wind power ducts generate wind power, thermal energy enhances the wind power, and the wind power drives the wind turbines to generate electricity.

3. The zero-carbon energy system according to claims 1 and 2 is characterized in that: the thermal energy is selected from various waste heat, residual heat, solar energy and biomass combustion thermal energy.

4. The zero-carbon energy system according to claims 1 and 2 is characterized in that the thermal energy can be replaced by the wind power of various ventilation systems.

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