Solar heat utilization system based on thermochemical long-time heat storage

Abstract

The invention discloses a solar heat utilization system based on thermochemical long-time heat storage, which relates to the technical field of solar heat storage and comprises a solar heat collector and a spiral transportation heat collection pipe. The spiral transportation heat collection pipe is arranged at the light condensation position of the solar heat collector, a particle inlet is formed in one end of the spiral transportation heat collection pipe, and a particle outlet is formed in the other end of the spiral transportation heat collection pipe. A spiral blade is arranged in the spiral conveying heat collecting pipe, and the spiral conveying heat collecting pipe is filled with thermochemical particles. The heat storage density is improved, meanwhile, long-term storage is facilitated, and abundant solar energy resources in the daytime in summer are stored through thermochemical particles and used for heat supply in winter or at night. The energy conversion efficiency and heat storage timeliness of the system are improved while the system is simplified.

Description

Technical Field

[0001] The present invention relates to the field of solar thermal storage technology, and in particular to a solar thermal utilization system based on thermochemical long-term thermal storage. Background Art

[0002] With the continuous growth of energy demand, traditional fossil fuel energy is gradually facing problems such as resource depletion and environmental pollution. Therefore, it is particularly important to develop renewable and environmentally friendly clean energy. As a clean and sustainable energy source, solar energy has received widespread attention. However, the intermittent and instability of solar energy, especially the seasonal changes in sunshine duration and intensity, limit its widespread application in energy supply. As a key technology, solar thermal storage technology can effectively convert solar energy into thermal energy, store and release it when needed, thereby solving the challenges of intermittent and unstable solar energy and achieving balanced supply and sustainable utilization of energy.

[0003] Existing solar thermal storage technologies mainly include hot water storage, phase change material storage, thermal conductor storage and other methods. These technologies have their own characteristics and meet the actual application needs to a certain extent. However, these technologies still have certain limitations in terms of thermal storage efficiency, thermal storage capacity, thermal release stability, etc., and it is difficult to fully meet the efficient and continuous thermal storage needs of modern and large-scale solar energy utilization systems.

[0004] Hot water storage technology is the most traditional and widely used method. Its basic principle is to convert solar energy into thermal energy and store hot water in an insulated container so that the heat can be released when needed. Although this method is simple and the equipment is mature, its heat storage efficiency is often limited by the thermal insulation performance of the water storage container. During long-term storage, especially in high-temperature environments, hot water is prone to heat loss, resulting in a significant decrease in the heat storage effect. In addition, the capacity of hot water storage is limited and cannot effectively cope with long-term, large-scale thermal energy needs. High-temperature storage is prone to cause hot water evaporation and corrosion problems, affecting the stability and service life of the system.

[0005] Phase change material (PCM) heat storage technology can efficiently store and release thermal energy due to its characteristic of phase change within a specific temperature range. Phase change materials can convert between solid and liquid states, store heat by absorbing or releasing latent heat of phase change, and have a high thermal energy storage density. However, a major problem with phase change materials is their limited temperature range and phase change efficiency. In practical applications, the heat capacity and phase change process of phase change materials are often limited by temperature fluctuations, and it is difficult to maintain stable performance during high temperature and long-term heat storage. In addition, the stability and cycle performance of the material itself may also attenuate during multiple charging and discharging processes, affecting its long-term use effect.

[0006] Thermal conductor heat storage technology mainly relies on high thermal conductivity materials (such as metals, ceramics, etc.) to quickly conduct heat energy, store solar heat in thermal conductors, and quickly release heat energy through their efficient thermal conductivity. Although this method can provide high thermal conduction efficiency in a short period of time, it also faces bottlenecks in heat storage capacity and long-term heat storage. Since thermal conductor materials usually have high thermal conductivity, heat loss will occur on their surface during long-term storage, resulting in a gradual decrease in the heat storage effect. In addition, the thermal conductivity efficiency of thermal conductors is often affected by changes in ambient temperature and the design of heat exchange equipment, so its stability in high temperature environments is difficult to guarantee.

[0007] Thermochemical energy storage is a technology that stores and releases thermal energy through reversible chemical reactions. During the heat storage process, the reactants absorb ambient heat under heating and convert it into chemical energy to form compounds in a stored state; when energy is needed, these compounds release the previously stored heat through exothermic reactions. Common heat storage materials include metal hydrides and certain salts (such as MgSO4·2H2O, etc.), which have the advantages of high energy density and long-term storage. Despite challenges such as reaction speed and material stability, thermochemical energy storage shows good potential in renewable energy systems and industrial applications, and is an important way to improve energy utilization efficiency. Solar thermal utilization technology that uses thermochemical heat storage materials such as hydrated salts to store heat for a long time after desorption has broad prospects. With the growing demand for energy efficiency and environmental protection, thermochemical long-term heat storage technology is attracting more and more attention from researchers.

[0008] At present, thermochemical long-term heat storage technology is a highly efficient energy storage method with high energy storage density and long energy storage time. In particular, porous hydrated salt particles are used as thermochemical long-term heat storage medium. This material not only has high solar energy absorption rate and energy storage density, but also shows good stability and wear resistance during cyclic use.

[0009] In summary, it is found that although the existing solar thermal storage technology can achieve a certain degree of thermal energy storage and release in the short term, it still has many shortcomings when facing the demand for heat storage under long-term, medium and high temperature conditions. Especially in high temperature environments, the performance of these heat storage media is easily affected by heat loss, thermal decay or material aging, making long-term storage and stable release of heat difficult. Therefore, how to improve the thermal stability of the heat storage medium, increase the heat storage capacity and efficiency, and reduce energy loss has become a key issue in the current development of solar thermal storage technology.

[0010] Existing solar thermal storage technologies mainly include hot water storage, phase change material storage, and thermal conductor storage. These methods have certain limitations in terms of heat storage efficiency, heat storage capacity, and stability of heat release. Especially under long-term storage and high temperature conditions, the performance of these heat storage media is easily affected by heat loss or thermal decay, making it difficult to achieve efficient long-term heat preservation and stable release. In addition, the design of traditional thermochemical reactors is complex, costly, and has a greater impact on the environment. Summary of the invention

[0011] In order to solve the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a solar thermal utilization system based on thermochemical long-term heat storage, which realizes the effective storage and efficient utilization of waste heat by utilizing the formation and decomposition process of hydrates.

[0012] To achieve the above object, the present invention provides the following solutions:

[0013] The present invention provides a solar thermal utilization system based on thermochemical long-term heat storage, comprising a solar collector and a spiral transport heat collecting tube; the spiral transport heat collecting tube is arranged at the focusing point of the solar collector, one end of the spiral transport heat collecting tube is provided with a particle inlet, and the other end of the spiral transport heat collecting tube is provided with a particle outlet; the spiral transport heat collecting tube is provided with spiral blades, and the spiral transport heat collecting tube is filled with thermochemical particles.

[0014] Optionally, the solar collector is a trough collector.

[0015] Optionally, the trough collector includes a solar collector plate, the upper surface of the solar collector plate is an arc-shaped reflective mirror surface, and the heat collecting tube is arranged at the focusing point of the arc-shaped reflective mirror surface.

[0016] Optionally, a bracket is provided at the bottom of the solar thermal collecting panel.

[0017] Optionally, a vacuum pump is provided at the particle outlet end of the spiral transport heat collecting pipe, and an air inlet of the vacuum pump is connected to the interior of the spiral transport heat collecting pipe.

[0018] Optionally, the spiral blade is provided with spoiler ribs.

[0019] Optionally, the spiral blade is a flexible spiral blade without a screw.

[0020] Optionally, a water pipe is further provided in the spiral transport heat collecting pipe, and a plurality of atomizing nozzles are provided on the water pipe.

[0021] Optionally, the thermochemical particles are MgSO4·2H2O.

[0022] Optionally, a moving bed heat exchanger is provided at the particle outlet end of the spiral transport heat collecting tube, and the particle outlet is connected to the particle inlet of the moving bed heat exchanger.

[0023] Compared with the prior art, the present invention has achieved the following technical effects:

[0024] The present invention is a solar thermal utilization system based on thermochemical long-term heat storage, which uses thermochemical particles to directly store the heat collected by the solar collector. By using thermochemical reactions to store solar energy, the surplus solar energy during the summer daytime can be efficiently converted into thermal energy and stored in thermochemical particles. Thermochemical particles are easy to store and transport for a long time, and can provide stable heating by releasing heat in winter or at night, thereby greatly improving the utilization rate of solar energy, solving the timeliness problem in solar energy storage and release, and having important application prospects.

[0025] Directly storing the heat collected by solar collectors through thermochemical reactions greatly improves the thermal energy storage density and system efficiency. This technology is not only suitable for heating and hot water systems in homes, industries and commercial buildings, but can also play an important role in remote areas, disaster emergency response and infrastructure construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 It is a schematic structural diagram of the solar thermal collector device in the present invention;

[0028] Figure 2 It is a structural schematic diagram of the waste heat utilization device in the present invention;

[0029] Figure 3 This is a flow chart of the solar energy waste heat utilization system in the present invention.

[0030] Description of reference numerals:

[0031] 1. Solar collector plate; 2. Particle inlet; 3. Spiral transport collector tube; 4. Vacuum pump; 5. Particle outlet; 6. Bracket; 7. Spoiler fins; 8. Spiral blades; 9. Atomizing nozzle; 10. Moving bed heat exchanger. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] When MgSO4·2H2O is heated at about 285°C, it will gradually dehydrate and transform into MgSO4 (anhydrous), and absorb a large amount of heat. Similarly, in the process of waste heat utilization, MgSO4 will absorb water and gradually generate MgSO4·2H2O after contacting water vapor, releasing a large amount of heat and heating to about 173°C, which is suitable for auxiliary heating of water vapor; if the flow rate of water vapor is increased, MgSO4·nH2O (n=3~7) will be further generated. Although the temperature rise will be reduced to 70°C, the heat release will increase significantly, which is suitable for home heating and heavy oil thermal recovery. It is worth noting that the operating temperature of the trough solar collector can reach 300~400°C, which fully meets the requirements of complete desorption of hydrated salt particles. The present invention stores heat in thermochemical particles for easy storage and transportation. If it is sealed and stored, it can realize the flexible utilization of its stored heat in multiple scenarios across seasons and distances.

[0034] The purpose of the present invention is to provide a solar thermal utilization system based on thermochemical long-term heat storage, which realizes effective storage and efficient utilization of waste heat by utilizing the formation and decomposition process of hydrates (such as MgSO4·2H2O desorbing to MgSO4 under heat and MgSO4 adsorbing water vapor to generate MgSO4·2H2O and releasing heat).

[0035] While increasing the heat storage density, it is also beneficial for long-term storage, storing the abundant solar energy resources during the summer daytime through thermochemical particles for heating in the winter or at night. The present invention simplifies the system while improving the energy conversion efficiency and heat storage timeliness of the system.

[0036] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] Embodiment 1:

[0038] like Figure 1As shown, this embodiment provides a solar thermal utilization system based on thermochemical long-term heat storage, including a solar collector and a spiral transport collector tube 3; the spiral transport collector tube 3 is arranged at the focusing point of the solar collector, one end of the spiral transport collector tube 3 is provided with a particle inlet 2, and the other end of the spiral transport collector tube 3 is provided with a particle outlet 5; spiral blades 8 are arranged in the spiral transport collector tube 3, and the spiral transport collector tube 3 is filled with MgSO4·2H2O particles.

[0039] In this specific embodiment, the solar collector is a trough collector, which includes a solar collector plate 1, the upper surface of which is an arc-shaped reflective mirror, and the heat collecting tube is arranged at the focusing point of the arc-shaped reflective mirror. A bracket 6 is arranged at the bottom of the solar collector plate 1.

[0040] A vacuum pump 4 is provided at the particle outlet 5 end of the spiral transport heat collecting pipe 3, and an air inlet of the vacuum pump 4 is connected to the inside of the spiral transport heat collecting pipe 3. The vacuum pump 4 is used to absorb water vapor generated by thermal desorption of MgSO4·2H2O.

[0041] The spiral blades 8 are provided with spoiler fins 7 to increase the particle disturbance.

[0042] A flexible screw conveyor is used inside the solar collector tube to circulate and stir the particles, which can achieve the effect of stable and uniform particle transportation. At the same time, the MgSO4 that stores heat can be stored for a long time in a sealed storage tank and can be flexibly used in winter or at night when solar energy resources are scarce.

[0043] The specific working process is as follows: MgSO4·2H2O thermochemical particles are transported to the solar collector through a screw feeder, and the external solar collector plate 1 collects heat and gathers it into the spiral transport collector tube 3. The MgSO4·2H2O in the spiral transport collector tube 3 is gradually dehydrated and transformed into MgSO4 (anhydrous), absorbing and storing a large amount of heat; at this time, the flexible spiral blades 8 in the spiral transport collector tube 3 stir the particles to fully exchange heat while simultaneously sending them to the particle outlet 5. In addition, the fins on the spiral blades 8 increase the disturbance of the particles. The water vapor generated by the thermal desorption of MgSO4·2H2O is discharged through the vacuum pump 4, thereby preventing the particles from sticking together. The hydrated salt particles that have completed the heat exchange are collected in the container tank for storage.

[0044] Since MgSO4·2H2O thermochemical particles have the characteristics of high heat storage density and easy storage and transportation, they can achieve long-term storage of heat and be sent to various places for use when there is a high demand for heating.

[0045] Embodiment 2:

[0046] like Figures 1 to 3As shown, this embodiment is an improved embodiment based on the first embodiment. In this specific embodiment, the spiral blade 8 is a flexible spiral blade 8 without a screw. A water pipe is also provided in the spiral transport heat collection pipe 3, and a plurality of atomizing nozzles 9 are provided on the water pipe. Water is transported from the outside to the spiral transport heat collection pipe 3 and is converted into droplets through the atomizing nozzles 9 to mix with the thermochemical particles for adsorption reaction. A moving bed heat exchanger 10 is provided at the particle outlet 5 end of the spiral transport heat collection pipe 3, and the particle outlet 5 is connected to the particle inlet of the moving bed heat exchanger 10.

[0047] When waste heat is used, the particles are sent to the spiral transport heat collection pipe 3, and water is transported from the outside to the internal pipe and becomes droplets through the atomizing nozzle 9, which mixes with the thermochemical particles to undergo an adsorption reaction, and the temperature rises. Subsequently, the thermochemical particles after the reaction temperature rise are transported to the moving bed heat exchanger 10, which heats the cold air flowing in the heat exchanger pipe into warm air and is sent to various places for heating. After the heat exchange is completed, the particles are sent to the well site for recycling and treatment and can be recycled again.

[0048] It should be noted that it is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any figure mark in the claims should not be regarded as limiting the claims involved.

[0049] The present specification uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A solar thermal utilization system based on thermochemical long-term heat storage, characterized in that: It includes a solar collector and a spiral transport heat collecting tube; the spiral transport heat collecting tube is arranged at the focusing point of the solar collector, one end of the spiral transport heat collecting tube is provided with a particle inlet, and the other end of the spiral transport heat collecting tube is provided with a particle outlet; the spiral transport heat collecting tube is provided with spiral blades, and the spiral transport heat collecting tube is filled with thermochemical particles.

2. The solar thermal utilization system based on thermochemical long-term heat storage according to claim 1 is characterized in that: The solar thermal collector is a trough type collector.

3. The solar thermal utilization system based on thermochemical long-term heat storage according to claim 2 is characterized in that: The trough collector comprises a solar heat collecting plate, the upper surface of which is an arc-shaped reflecting mirror surface, and the heat collecting tube is arranged at the focusing position of the arc-shaped reflecting mirror surface.

4. The solar thermal utilization system based on thermochemical long-term heat storage according to claim 3 is characterized in that: A bracket is arranged at the bottom of the solar heat collecting panel.

5. The solar thermal utilization system based on thermochemical long-term heat storage according to claim 1 is characterized in that: A vacuum pump is provided at the particle outlet end of the spiral transport heat collecting pipe, and an air inlet of the vacuum pump is connected to the interior of the spiral transport heat collecting pipe.

6. The solar thermal utilization system based on thermochemical long-term heat storage according to claim 1 is characterized in that: The spiral blades are provided with spoiler ribs.

7. The solar thermal utilization system based on thermochemical long-term heat storage according to claim 1 is characterized in that: The spiral blade is a flexible spiral blade without a screw.

8. The solar thermal utilization system based on thermochemical long-term heat storage according to claim 1 is characterized in that: A water pipe is also provided in the spiral transport heat collecting pipe, and a plurality of atomizing nozzles are provided on the water pipe.

9. The solar thermal utilization system based on thermochemical long-term heat storage according to claim 1 is characterized in that: The thermochemical particles are MgSO4·2H2O.

10. The solar thermal utilization system based on thermochemical long-term heat storage according to claim 1 is characterized in that: A moving bed heat exchanger is provided at the particle outlet end of the spiral transport heat collecting pipe, and the particle outlet is connected to the particle inlet of the moving bed heat exchanger.

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