Solar heat collection system capable of controlling heat storage

Abstract

The invention provides a solar heat collection system for controlling heat storage, which comprises a main pipeline, a first branch pipeline and a second branch pipeline, the first branch pipeline and the second branch pipeline are arranged in parallel with the main pipeline, a plurality of heat accumulators arranged in parallel are arranged on the first branch pipeline, a heat accumulator valve is arranged on an inlet pipeline of each heat accumulator, and a heat accumulator valve is arranged on an outlet pipeline of each heat accumulator. A heat exchanger is arranged on the second branch pipeline, a heat exchanger valve is arranged on the second branch pipeline, a main valve is arranged on the main pipeline, a temperature sensor is arranged to detect the output temperature of a cold source of the heat exchanger, and when the detected output temperature of the cold source of the heat exchanger is lower than a preset value, all heat accumulator valves are controlled to be closed; and hot fluid is ensured to enter the heat exchanger for heat exchange. The heat accumulator is controlled to accumulate heat according to the output temperature of the heat exchanger so as to ensure that the output temperature of the heat exchanger meets user requirements.

Description

Technical Field

[0001] The present invention relates to a solar energy system, and more particularly to a solar heat collection system for controlling heat storage. Background Art

[0003] Solar energy is a clean energy source that is inexhaustible and has a huge resource volume. The total amount of solar radiation energy received by the earth's surface every year is 1×10 18 kW·h, which is more than ten thousand times the total annual energy consumption of the world. However, due to the small energy density of solar radiation reaching the earth (about one kilowatt per square meter) and its discontinuity, it brings certain difficulties to large-scale development and utilization. Therefore, in order to widely utilize solar energy, not only technical problems need to be solved, but also it must be economically competitive with conventional energy sources.

[0004] It has been found in applications that continuous solar heat collection heating or no heating at night will cause the internal fluid to form stability, that is, the fluid no longer flows or has very little fluidity, or the flow rate is stable, resulting in a significant reduction in the performance of the heat collection tube, thereby affecting the heating efficiency of the heat collection tube. Therefore, it is necessary to improve the above-mentioned solar heat collection device.

[0005] For the excess solar energy, heat storage can be used to store heat, but the current utilization level of solar heat storage is not high. In view of the above problems, the present invention provides a new intelligent controlled solar heat storage system to perform heat storage operations according to different situations.

[0006] In response to the above requirements, the present invention has been improved to be able to perform heat storage while ensuring user needs, and at the same time, specifically control the heat storage process intelligently. Summary of the Invention

[0007] In order to achieve the above object, the technical solution of the present invention is as follows: A solar heat collection system for controlling heat storage, the system includes a main pipeline, a first branch pipeline and a second branch pipeline arranged in parallel with the main pipeline. A plurality of heat storage devices arranged in parallel are provided on the first branch pipeline, and a heat storage device valve is provided on the inlet pipeline of each heat storage device. 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, and 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, all the heat storage device valves are controlled to be closed to ensure that the hot fluid enters the heat exchanger for heat exchange.

[0008] As an improvement, when the detected output temperature of the cold source of the heat exchanger is higher than the predetermined value, at least one heat storage device valve is controlled to be opened for heat storage operation.

[0009] As an improvement, while controlling the reduction of the opening degree of the heat exchanger valve, the number of opened accumulator valves is controlled according to the reduced opening degree.

[0010] As an improvement, a valve is provided at the outlet of the collector, and a temperature sensor is provided in the collector for detecting the temperature of the fluid heated in the heater. When the temperature of the fluid in the collector detected is lower than a predetermined value, the controller controls the main pipeline valve to open, the inlet valve and the outlet valve of the main pipeline to close, the heat exchanger valve to open, and at least a part of the accumulator valves to open, so that a loop is formed between the accumulator and the heat exchanger.

[0011] As an improvement, the controller controls a part of the accumulator valves to open and another part of the accumulator valves to close.

[0012] As an improvement, when the temperature of the heat storage material in a certain accumulator detected is lower than the set value, the corresponding accumulator valve is closed, and at the same time, one of the other part of the accumulator valves 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 arranged in the tube side of the heat exchanger.

[0015] As an improvement, the fluid in the shell side is a gas. The baffle includes multiple groups, and each group of baffles includes a lower baffle located at the lower part of the shell and an upper baffle located at the upper part of the shell; along the flowing direction of the gas in the shell side, the ratio of the area of the lower baffle in different groups of baffles to the area of the upper baffle is gradually reduced.

[0016] As an improvement, along the flowing direction of the gas in the shell side, the decreasing amplitude of the ratio of the area of the lower baffle in the baffle group to the area of the upper baffle is getting smaller and smaller.

[0017] Compared with the prior art, the present invention has the following advantages: By providing multiple accumulators, the present invention controls the accumulators to store heat according to the output temperature of the heat exchanger to ensure that the output temperature of the heat exchanger meets the needs of users. Description of the Drawings

[0018] Figure 1 is a schematic structural diagram of the solar heat collection system of the present invention. Detailed Embodiment

[0019] The following makes a detailed description of the specific embodiments of the present invention with reference to the drawings.

[0020] In this article, if there is no special description, for those involving formulas, " / " represents division, and "×", "*" represent multiplication.

[0021] Figure 1A solar collector system is disclosed. As Figure 1 shown, it includes a main solar pipeline 1, a first branch pipeline 2 and a second branch pipeline 3 which are arranged in parallel with the main pipeline. The hot fluid flowing in the main solar pipeline 1 is from the fluid heated in the solar collector. The preferred fluid is water.

[0022] As Figure 1 shown, a plurality of heat accumulators 4 arranged in parallel are provided on the first branch pipeline 2, a heat accumulator valve 5 is provided on the inlet pipeline of each heat accumulator 4, a heat exchanger 6 is provided on the second branch pipeline, a heat exchanger valve 7 is provided on the second branch pipeline, an inlet valve 8 is provided on the inlet pipeline of the main pipeline 1, an outlet valve 9 is provided on the outlet pipeline, and a main valve 10 is provided on the pipeline where the main pipeline is in parallel with the first branch pipeline. As an improvement, when the output temperature of the cold source of the heat exchanger detected is lower than the predetermined value, all the heat accumulator valves are controlled to be closed to ensure that all the hot fluid enters the heat exchanger for heat exchange. When the output temperature of the cold source of the heat exchanger detected is higher than the predetermined value, at least one heat accumulator valve is controlled to be opened for heat storage operation. Preferably, the opening degree of the heat exchanger valve is simultaneously controlled to decrease. The number of heat accumulator valves opened is controlled according to the decreased opening degree to ensure that the amount of fluid entering the heat accumulator corresponds to the decreased amount of fluid entering the heat exchanger.

[0023] As an improvement, a valve is provided at the outlet of the collector, and a temperature sensor is provided in the collector to detect the temperature of the fluid heated in the heater. When the temperature of the fluid in the collector detected is lower than the predetermined value, the controller controls the main pipeline valve to open, the inlet valve 8 and the outlet valve 9 of the main pipeline to close, the heat exchanger valve to open, and at least a part of the heat accumulator valves to open, so that a loop is formed between the heat accumulator and the heat exchanger. The present invention can intelligently realize the circulation of the pipelines of the heat accumulator and the heat exchanger according to the heat collection situation of the solar collector, thus ensuring the normal operation of the heat exchanger.

[0024] As an improvement, the controller controls a part of the heat accumulator valves to open and another part of the heat accumulator valves to close; when the temperature of the heat storage material in a certain heat accumulator detected is lower than the set value, the corresponding heat accumulator valve is closed, and at the same time, one of the other part of the heat accumulator valves is opened for heat storage. The above operations can ensure that the heat exchanger always operates normally, avoiding the output temperature of the heat exchanger being too high when all the heat accumulators are opened at the beginning, so as to maintain normal operation.

[0025] A temperature sensor is provided in the heat accumulator 4 to detect the temperature of the heat storage material in the heat accumulator, and the controller controls the opening and closing of the corresponding heat accumulator valve 5 according to the detected temperature of the heat storage material.

[0026] Preferably, the inlet valve 8 and the outlet valve 9 are opened, and the main valve 10 is closed. At this time, the fluid enters the heat accumulator and the heat exchanger 6.

[0027] Preferably, the inlet valve 8 and the outlet valve 9 are opened, the main pipe valve 10 is closed, and at least a part of the heat exchanger valve 7 and the heat accumulator valve are opened so that the fluid can enter at least a part of the heat accumulator and the heat exchanger for heat storage or heat exchange.

[0028] As an improvement, when the temperature of the heat storage material in the detected heat accumulator exceeds a predetermined value, it indicates that the heat accumulator has completed heat storage and cannot perform further heat storage. At this time, 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 perform heat storage, and the corresponding heat accumulator valve is opened.

[0029] In the present invention, by providing a plurality of heat accumulators, a temperature sensor is provided in each heat accumulator to detect the temperature of the heat storage material, and then the heat storage condition of the heat accumulator is determined according to the temperature of the heat storage material. The heat accumulator valve is opened or closed targeted, so as to perform heat storage on the heat accumulator targeted, so that the heat accumulator that has completed heat storage stops heat storage in time, and the heat is used for the heat storage of other heat accumulators, avoiding waste of heat.

[0030] As an improvement, the controller controls a part of the heat accumulator valves to be opened and another part of the heat accumulator valves to be closed, so that the fluid enters a part of the heat accumulators for heat storage; when one of the heat accumulators has completed heat storage, the corresponding heat accumulator valve is closed, and the controller opens one of the other heat accumulator valves, so that the hot fluid enters one of the other parts of the heat accumulators for heat storage.

[0031] The above operations can ensure that a part of the heat accumulators are filled with heat first, and then the next heat accumulator continues to store heat, which can ensure that a part of the heat storage is preferentially satisfied when the heat is not very sufficient. Avoid heat dispersion and ensure that the heat stored can be fully exchanged for heat.

[0032] As an improvement, the controller controls the heat exchanger valve to be opened, and at the same time adjusts a part or all of the heat accumulator valves to be closed to ensure the operation of the heat exchanger. Preferably, a temperature sensor is provided to detect the output temperature of the cold source of the heat exchanger, and a part or all of the heat accumulator valves are opened or closed according to the output temperature.

[0033] Through the above control method, the present invention simultaneously opens or closes one or more heat accumulators for heat storage operations according to the specific heat exchange conditions of the heat exchanger, and can perform heat storage while meeting the heat exchange requirements of the heat exchanger, realizing the dual requirements of heat storage and heat exchange.

[0034] As an improvement, the heat exchanger is a shell-and-tube heat exchanger.

[0035] As an improvement, a baffle 11 is provided in the tube side of the heat exchanger.

[0036] As an improvement, the shell-and-tube heat exchanger is a horizontal shell-and-tube heat exchanger.

[0037] As an improvement, the hot fluid flows through the tube side and the cold fluid flows through the shell side.

[0038] As an improvement, the shell side and the tube side are in countercurrent flow. Along the flow direction of the fluid in the tube side, from the tube side inlet to the middle position of the tube side, the spacing of the baffle plates continuously increases. Then from the middle position of the tube side to the tube side outlet, the spacing of the baffle plates continuously decreases. Because in the countercurrent process, the heat transfer amount per unit length of the shell side and the tube side along the fluid flow process is relatively uniform, thus making the overall heat transfer effect the best. However, it is found in experiments and simulations that the heat transfer amount in the middle is significantly greater than that at the inlet and outlet of the tube side. Therefore, by changing the baffle plate spacing, the heat transfer area between the tube side fluid and the shell side fluid source in the baffle plates also changes. Therefore, the uneven heat transfer amount is compensated by the area change, so as to further improve the heat transfer efficiency.

[0039] As an improvement, along the flow direction of the fluid in the tube side, from the tube side inlet to the middle position of the tube side, the increasing amplitude of the baffle plate spacing continuously increases. Then from the middle position of the tube side to the tube side outlet, the decreasing amplitude of the baffle plate spacing continuously decreases. The change of the above amplitude can make the heat transfer amount per unit length of the whole fluid motion more uniform and further improve the heat transfer efficiency.

[0040] The fluid in the shell side is a gas. The baffle plates include multiple groups, and each group of baffle plates includes a lower baffle plate located at the lower part of the tube shell and an upper baffle plate located at the upper part of the tube shell; along the flow direction of the gas in the shell side, the ratio of the area of the lower baffle plate to the area of the upper baffle plate in different groups of baffle plates gradually decreases.

[0041] During the research process, it is found that the heat transfer on the cross-section of the traditional heat exchanger baffle plates in the gas flow direction is uneven. The farther away from the inlet, the better the heat transfer effect in the upper part of the shell side and the worse the heat transfer effect in the lower part of the shell side. The main reason is that as the gas continuously flows. Because the gas density is small, the gas flows upward, thus making the heat transfer gas in the upper part significantly increase. Therefore, it is necessary to design a heat transfer structure for improvement. In the present invention, along the flow direction of the gas, the area ratio of the lower baffle plate to the upper baffle plate in the baffle plate group changes. The gas in the shell side gradually converges more and more towards the center as it flows, making the fluid center strengthen heat transfer with the heat exchange tubes around the tube shell, changing the past heat transfer mode, strengthening the heat transfer efficiency at different positions, making the overall heat transfer uniform, and further achieving the purpose of strengthening heat transfer.

[0042] As an improvement, along the gas flow direction in the shell side, the ratio of the area of the lower baffle plate to the area of the upper baffle plate in the baffle plate group gradually decreases with a decreasing rate. Through the change of the above rate, the heat transfer can be further made uniform as a whole, and the purpose of enhancing heat transfer is further achieved.

[0043] Although the present invention has been disclosed above with preferred embodiments, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be subject to the scope defined by the claims.

Claims

1. A solar heat collection system for controlling heat storage, the system comprising a main pipeline, a first branch pipeline and a second branch pipeline arranged in parallel with the main pipeline, a plurality of heat storage devices arranged in parallel on the first branch pipeline, a heat storage device valve arranged on the inlet pipeline of each heat storage device, a heat exchanger arranged on the second branch pipeline, a heat exchanger valve arranged on the second branch pipeline, a main valve arranged on the main pipeline, and a temperature sensor arranged 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 the heat storage device valves are controlled to be closed to ensure that all the hot fluid enters the heat exchanger for heat exchange.

2. The heat collection system according to claim 1, wherein When the detected output temperature of the cold source of the heat exchanger is higher than the predetermined value, at least one heat storage device valve is controlled to be opened for heat storage operation.

3. The heat collection system according to claim 2, wherein Meanwhile, the opening degree of the heat exchanger valve is controlled to decrease, and the number of opened heat storage device valves is controlled according to the decreased opening degree.

4. The heat collection system according to claim 1, wherein A valve is arranged at the outlet of the heat collector, and a temperature sensor is arranged in the heat collector to detect the temperature of the fluid heated in the heater. When the detected temperature of the fluid in the heat collector is lower than the predetermined value, the controller controls the main pipeline valve to be opened, the inlet valve and the outlet valve of the main pipeline to be closed, the heat exchanger valve to be opened, and at least a part of the heat storage device valves to be opened, so as to form a loop between the heat storage device and the heat exchanger.

5. The heat collection system according to claim 4, characterized in that, The controller controls a part of the heat storage device valves to be opened and another part of the heat storage device valves to be closed.

6. The heat collection system according to claim 4, characterized in that When the detected temperature of the heat storage material in a certain heat storage device is lower than the set value, the corresponding heat storage device valve is closed, and at the same time, one of the other part of the heat storage device valves is opened for heat storage.

7. The heat collection system according to claim 1, wherein The heat exchanger is a shell-and-tube heat exchanger.

8. The heat collection system according to claim 7, wherein Baffle plates are arranged in the tube side of the heat exchanger.

9. The heat collection system according to claim 8, wherein, The fluid in the shell side is a gas. The baffle plates include multiple groups, and each group of baffle plates includes a lower baffle plate located at the lower part of the shell and an upper baffle plate located at the upper part of the shell; along the flow direction of the gas in the shell side, the ratio of the area of the lower baffle plate to the area of the upper baffle plate in different groups of baffle plates gradually decreases.

10. The heat collection system according to claim 9, wherein, Along the flow direction of the gas in the shell side, the decreasing amplitude of the ratio of the area of the lower baffle plate to the area of the upper baffle plate in the baffle plate group gradually becomes smaller.

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