A thermal storage controlled solar energy collection system
By introducing multiple parallel heat storage devices and heat exchangers into the solar thermal collector system, combined with temperature sensors and baffle plate design, the problems of fluid stability and low heat storage utilization are solved, achieving efficient heat storage and heat exchange control and improving heat collection efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ZHONGBEI UNIV
- Filing Date
- 2024-03-05
- Publication Date
- 2026-06-19
AI Technical Summary
Existing solar thermal systems suffer from fluid stability issues when solar energy is continuously collecting heat or when heating is not performed at night, which affects the performance of the heat collection tubes and results in low utilization of heat storage.
Multiple parallel heat accumulators and heat exchangers are used. Temperature sensors detect the temperature of the heat exchangers and heat accumulators, and the opening and closing of the heat accumulator valves are intelligently controlled. Combined with the shell-and-tube heat exchanger with baffle design, the fluid flow and heat exchange process are optimized.
It enables intelligent control of heat storage and heat exchange based on demand, improves heat collection efficiency, avoids heat waste, and ensures normal operation of the heat exchanger and full utilization of heat.
Smart Images
Figure CN120252179B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a solar energy system, and more particularly to a solar thermal collector system for controlled heat storage. Background Technology
[0002] Solar energy is a clean, inexhaustible energy source with enormous reserves; the total amount of solar radiation received by the Earth's surface each year is 1 × 10⁻⁶. 18 The solar energy density is kW·h, which is more than ten thousand times the world's total annual energy consumption. However, due to the low energy density of solar radiation reaching the Earth (approximately one kilowatt per square meter) and its discontinuous nature, large-scale development and utilization face certain difficulties. Therefore, in order to widely utilize solar energy, not only are technical problems to be solved, but it must also be economically competitive with conventional energy sources.
[0003] Applications have revealed that continuous solar heating or no heating at night leads to the internal fluid becoming stable, meaning the fluid stops flowing, has very little flow, or the flow rate is stable. This significantly weakens the performance of the collector tube, thus affecting its heating efficiency. Therefore, improvements to the aforementioned solar collector device are necessary.
[0004] Excess solar energy can be stored through heat storage, but the utilization rate of solar heat storage is currently low. To address this issue, this invention provides a new intelligent control solar heat storage system that performs heat storage operations according to different situations.
[0005] To address the aforementioned needs, this invention has been improved to ensure heat storage while meeting user requirements, and to provide targeted intelligent control of the heat storage process. Summary of the Invention
[0006] To achieve the above objectives, the technical solution of the present invention is as follows:
[0007] A controlled heat storage solar thermal collector system includes a main pipeline and a first branch pipeline and a second branch pipeline connected in parallel with the main pipeline. Multiple heat accumulators are installed in parallel on the first branch pipeline, and a heat accumulator valve is installed on the inlet pipeline of each heat accumulator. A heat exchanger is installed on the second branch pipeline, and a heat exchanger valve is installed on the second branch pipeline. A main valve is installed on the main pipeline. A temperature sensor is installed to detect the output temperature of the cold source of the heat exchanger. When the detected output temperature of the cold source of the heat exchanger is lower than a predetermined value, all heat accumulator valves are closed to ensure that the hot fluid enters the heat exchanger for heat exchange.
[0008] As an improvement, when the output temperature of the detected heat exchanger cold source is higher than a predetermined value, at least one accumulator valve is controlled to open to perform heat storage operation.
[0009] As an improvement, the opening degree of the heat exchanger valve is reduced, and the number of accumulator valves opened is controlled according to the reduced opening degree.
[0010] As an improvement, a valve is installed at the collector outlet, and a temperature sensor is installed in the collector to detect the temperature of the fluid being heated in the heater. When the detected fluid temperature in the collector is lower than a predetermined value, the controller controls the main pipeline valve to open, the main pipeline inlet valve and outlet valve to close, the heat exchanger valve to open, and at least some of the accumulator valves to open, thereby forming a loop between the accumulator and the heat exchanger.
[0011] As an improvement, the controller opens some of the accumulator valves and closes others.
[0012] As an improvement, when the temperature of the heat storage material in a certain heat accumulator is lower than the set value, the corresponding heat accumulator valve is closed, while one of the valves in another group of heat accumulators is opened for heat storage.
[0013] As an improvement, the heat exchanger is a shell-and-tube heat exchanger.
[0014] As an improvement, baffles are provided in the tube side of the heat exchanger.
[0015] As an improvement, the fluid in the shell side is gas. The baffles comprise multiple sets, each set including a lower baffle located at the bottom of the shell and an upper baffle located at the top of the shell; along the flow direction of the gas in the shell side, the ratio of the area of the lower baffle to the area of the upper baffle in the different sets of baffles gradually decreases.
[0016] As an improvement, along the flow direction of the gas inside the shell, the ratio of the area of the lower baffle to the area of the upper baffle in the baffle assembly gradually decreases with decreasing amplitude.
[0017] Compared with the prior art, the present invention has the following advantages:
[0018] This invention uses multiple heat accumulators to control the heat accumulators to store heat based on the output temperature of the heat exchanger, thereby ensuring that the output temperature of the heat exchanger meets the user's needs. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of the solar thermal collector system of the present invention. Detailed Implementation
[0020] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.
[0021] Unless otherwise specified, in this article, " / " represents division, and "×" and "*" represent multiplication.
[0022] Figure 1 A solar collector system is disclosed. For example... Figure 1 As shown, the system includes a main solar power pipeline 1, a first branch pipeline 2 and a second branch pipeline 3 connected in parallel with the main pipeline. A hot fluid flows through the main solar power pipeline 1, the hot fluid originating from a fluid heated in a solar collector. The preferred fluid is water.
[0023] like Figure 1 As shown, multiple parallel-connected heat accumulators 4 are installed on the first branch pipeline 2, and a heat accumulator valve 5 is installed on the inlet pipe of each heat accumulator 4. A heat exchanger 6 and a heat exchanger valve 7 are installed on the second branch pipeline. An inlet valve 8 is installed on the inlet pipe of the main pipeline 1, and an outlet valve 9 is installed on the outlet pipe. A main valve 10 is installed on the pipeline connected in parallel with the first branch pipeline. As an improvement, when the output temperature of the detected cold source of the heat exchanger is lower than a predetermined value, all heat accumulator valves are controlled to close to ensure that the hot fluid enters the heat exchanger for heat exchange. When the output temperature of the detected cold source of the heat exchanger is higher than the predetermined value, at least one heat accumulator valve is controlled to open to perform heat storage operation. Preferably, the opening degree of the heat exchanger valves is reduced simultaneously. The number of heat accumulator valves opened is controlled according to the reduced opening degree to ensure that the amount of fluid entering the heat accumulator corresponds to the reduced amount of fluid entering the heat exchanger.
[0024] As an improvement, a valve is installed at the collector outlet, and a temperature sensor is installed in the collector to detect the temperature of the fluid being heated in the heater. When the detected fluid temperature in the collector is lower than a predetermined value, the controller controls the main pipeline valve to open, the main pipeline inlet valve 8 and outlet valve 9 to close, the heat exchanger valve to open, and at least some of the accumulator valves to open, thereby forming a loop between the accumulator and the heat exchanger. This invention also intelligently realizes the circulation of the accumulator and heat exchanger pipelines based on the solar collector's heat collection status, thus ensuring the normal operation of the heat exchanger.
[0025] As an improvement, the controller opens some accumulator valves while closing others. When the temperature of the heat storage material in a particular accumulator is detected to be lower than a set value, the corresponding accumulator valve is closed, while one of the valves in the other accumulator group is opened for heat storage. This operation ensures that the heat exchanger continues to operate normally, preventing the output temperature from becoming too high when all accumulators are initially open, thus maintaining normal operation.
[0026] A temperature sensor is installed inside the heat accumulator 4 to detect the temperature of the heat storage material inside the heat accumulator. The controller controls the opening and closing of the corresponding heat accumulator valve 5 according to the detected temperature of the heat storage material.
[0027] Preferably, the inlet valve 8 and outlet valve 9 are open, and the main pipe valve 10 is closed, at which point the fluid enters the accumulator and heat exchanger 6.
[0028] Preferably, the inlet valve 8 and outlet valve 9 are open, the main pipe valve 10 is closed, and at least a portion of the heat exchanger valve 7 and the accumulator valve are open, so that fluid can enter at least a portion of the accumulator and the heat exchanger for heat storage or exchange.
[0029] As an improvement, when the temperature of the heat storage material in the detected heat accumulator exceeds the predetermined value, it indicates that the heat accumulator has completed heat storage and cannot store heat again, so the corresponding heat accumulator valve 5 is closed; when the temperature of the heat storage material in the detected heat accumulator is lower than the predetermined value, it indicates that the heat accumulator can store heat, so the corresponding heat accumulator valve is opened.
[0030] This invention sets up multiple heat accumulators, each equipped with a temperature sensor to detect the temperature of the heat storage material. Based on the temperature of the heat storage material, the heat storage status of the heat accumulator is determined, and the heat accumulator valves are opened or closed in a targeted manner. This allows the heat accumulator to stop storing heat in a timely manner once it has completed its heat storage, and the heat is then used for the heat storage of other heat accumulators, thus avoiding the waste of heat.
[0031] As an improvement, the controller controls some of the accumulator valves to open and others to close, allowing fluid to enter some of the accumulators for heat storage; when one of the accumulators has finished storing heat, the corresponding accumulator valve is closed, and the controller opens one of the valves in another part of the accumulators, allowing the hot fluid to enter one of the accumulators in the other part for heat storage.
[0032] The above operation ensures that some heat accumulators are fully charged before moving on to the next, prioritizing the storage of heat when the available heat is insufficient. This prevents heat loss and ensures that the stored heat is fully exchanged.
[0033] As an improvement, the controller opens the heat exchanger valves while simultaneously closing some or all of the accumulator valves to ensure the operation of the heat exchanger. Preferably, a temperature sensor is used to detect the output temperature of the heat exchanger's cold source, and the controller opens or closes some or all of the accumulator valves based on the output temperature.
[0034] Through the above control method, the present invention can simultaneously open or close one or more accumulators to perform heat storage operation according to the specific heat exchange situation of the heat exchanger. It can perform heat storage while meeting the heat exchanger's heat exchange requirements, thus achieving the dual requirements of heat storage and heat exchange.
[0035] As an improvement, the heat exchanger is a shell-and-tube heat exchanger.
[0036] As an improvement, baffles 11 are provided inside the tube side of the heat exchanger.
[0037] As an improvement, the shell-and-tube heat exchanger is a horizontal shell-and-tube heat exchanger.
[0038] As an improvement, the hot fluid travels through the tube side, while the cold fluid travels through the shell side.
[0039] As an improvement, the shell-side and tube-side flow is counter-current. Along the flow direction of the fluid in the tube side, the spacing of the baffles continuously increases from the tube inlet to the middle of the tube side. Then, from the middle of the tube side to the tube outlet, the spacing of the baffles continuously decreases. Because the heat transfer per unit length along the fluid flow path is relatively uniform during counter-current flow, the overall heat transfer effect is optimal. However, experiments and simulations have shown that the heat transfer in the middle is significantly greater than that at the tube inlet and outlet. Therefore, by changing the baffle spacing, the heat transfer area between the tube-side fluid and the shell-side fluid source in the baffles also changes. This area change compensates for the uneven heat transfer, thereby further improving the heat transfer efficiency.
[0040] As an improvement, along the flow direction of the fluid within the tube, the spacing of the baffles increases progressively from the tube inlet to the middle of the tube. Then, from the middle of the tube to the tube outlet, the spacing of the baffles decreases progressively. This variation in spacing makes the heat transfer per unit length of the fluid flow more uniform, further improving heat transfer efficiency.
[0041] The fluid within the shell side is gas. The baffles comprise multiple sets, each set including a lower baffle located at the bottom of the shell and an upper baffle located at the top of the shell; along the flow direction of the gas within the shell side, the ratio of the area of the lower baffle to the area of the upper baffle in the different sets of baffles gradually decreases.
[0042] During the research, it was found that the heat transfer in the cross-section of the baffles in traditional heat exchangers is uneven along the gas flow direction. The heat transfer effect improves with increasing distance from the inlet, while it deteriorates at the bottom of the shell side. This is mainly due to the continuous flow of gas. Because of its low density, the gas flows upwards, significantly increasing the amount of gas in the upper part of the shell for heat transfer. Therefore, an improved heat transfer structure is needed. This invention changes the area ratio of the lower baffle to the upper baffle in the baffle assembly along the gas flow direction. This causes the gas in the shell side to gradually move towards the center, enhancing heat transfer around the tubes and changing the traditional heat transfer method. This improves heat transfer efficiency at different locations, resulting in more uniform heat transfer overall and further enhancing heat transfer.
[0043] As an improvement, along the flow direction of the gas within the shell side, the ratio of the area of the lower baffle to the area of the upper baffle in the baffle assembly gradually decreases with decreasing amplitude. This variation in amplitude further enhances the overall heat transfer uniformity, thereby further strengthening the heat transfer effect.
[0044] While the present invention has been disclosed above with reference to preferred embodiments, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.
Claims
1. A controlled solar thermal collection system, the system comprising a main pipeline and a first branch pipeline and a second branch pipeline connected in parallel with the main pipeline, wherein a plurality of heat accumulators are arranged in parallel on the first branch pipeline, and a heat accumulator valve is provided on the inlet pipeline of each heat accumulator; a heat exchanger is provided on the second branch pipeline, and a heat exchanger valve is provided on the second branch pipeline; a main valve is provided on the main pipeline; a temperature sensor is provided to detect the output temperature of the cold source of the heat exchanger; when the detected output temperature of the cold source of the heat exchanger is lower than a predetermined value, the heat accumulator valves are all closed to ensure that the hot fluid enters the heat exchanger for heat exchange; The heat exchanger is a shell-and-tube heat exchanger; baffles are installed in the tube side of the heat exchanger; the fluid in the shell side of the heat exchanger is gas; the baffles include multiple sets, each set of baffles includes a lower baffle located at the bottom of the shell and an upper baffle located at the top of the shell; along the flow direction of the gas in the shell, the ratio of the area of the lower baffle to the area of the upper baffle in different sets of baffles gradually decreases.
2. The thermal collection system of claim 1, wherein, When the output temperature of the detected heat exchanger cold source is higher than a predetermined value, at least one heat accumulator valve is opened to perform heat storage operation.
3. The thermal collection system of claim 2, wherein, Simultaneously, the opening degree of the heat exchanger valve is reduced, and the number of accumulator valves opened is controlled according to the reduced opening degree.
4. The thermal collection system of claim 1, wherein, A valve is installed at the outlet of the solar collector, and a temperature sensor is installed in the solar collector to detect the temperature of the fluid being heated in the heater. When the detected fluid temperature in the solar collector is lower than a predetermined value, the controller controls the main pipeline valve to open, the main pipeline inlet valve and outlet valve to close, the heat exchanger valve to open, and at least some of the accumulator valves to open, thereby forming a loop between the accumulator and the heat exchanger.
5. The heat collection system as described in claim 4, characterized in that, The controller opens some of the accumulator valves and closes others.
6. The thermal collection system of claim 4, wherein, When the temperature of the heat storage material in a certain heat accumulator is lower than the set value, the corresponding heat accumulator valve is closed, and at the same time, one of the valves in another group of heat accumulators is opened to store heat.
7. The thermal collection system of claim 1, wherein, Along the flow direction of the gas in the shell side, the ratio of the area of the lower baffle to the area of the upper baffle in different sets of baffles gradually decreases with decreasing amplitude.