Steam and hot water co-production system with solar energy coupled with fused salt heat storage

Abstract

The utility model discloses a solar energy coupling fused salt heat storage steam and hot water co-production system which comprises a high-temperature fused salt heat exchange tank area and a steam using area, a steam pipeline and a water return pipeline are connected between the high-temperature fused salt heat exchange tank area and the steam using area, and a first water pump is connected to the water return pipeline in series. A steam spherical tank is connected to the steam pipeline through a branch pipeline, a low-temperature fused salt heat exchange tank area is connected to the lower portion of the high-temperature fused salt heat exchange tank area and connected with a hot water using area and a solar PVT system through hot water pipes, and a fused salt heating area is connected to the lower portion of the low-temperature fused salt heat exchange tank area. A direct-current electric heater and a fused salt conveying pump are arranged in the fused salt heating area, the fused salt conveying pump conveys heated fused salt in the fused salt heating area into the high-temperature fused salt heat exchange tank area through a fused salt conveying pipe, and the direct-current electric heater is connected with a solar PVT system through a storage battery. According to the system, green electricity can be directly utilized for fused salt heat storage, the economical efficiency of the whole system is improved, and the energy utilization efficiency of the system is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of heat energy conversion and utilization, in particular to a steam and hot water cogeneration system of solar energy coupled with molten salt heat storage. Background Art

[0002] Molten salt heat storage technology is one of the important technical routes to meet the needs of long-term energy storage. The basic principle of molten salt heat storage involves storing energy in the form of thermal energy in a high-temperature medium, so that it can be converted into electrical energy or thermal energy output when energy is needed. Compared with other energy storage technologies, molten salt heat storage has unique advantages such as providing thermal energy and adapting to traditional power generation technologies, making it have great potential in dealing with power supply peak load auxiliary services, system heating and energy storage. However, in addition to safety issues, the current molten salt heat storage technology also has other problems.

[0003] First of all, most of the existing molten salt storage tank systems include two types of tanks: high-temperature tanks and low-temperature tanks. The two tanks are arranged separately and are large in size, occupying a large area and having low space utilization. At the same time, a large amount of molten salt is required, and the overall cost is high.

[0004] Secondly, the existing dual-tank system is poor in system flexibility, which is not conducive to replacement and updating in the event of a failure.

[0005] The temperature of the low-temperature tank in the existing dual-tank system still has room for heat release, which cannot be effectively utilized, reducing the overall thermal utilization efficiency. In addition, most molten salt heat storage systems have a single output form and no multi-heat source output mode.

[0006] At the same time, in the existing PVT (solar photovoltaic power generation / hot water) system, although the water in the pipes absorbs excess heat from the PV panels, the overall quality of the hot water is not high. The lack of heat makes it impossible to cope with multiple application scenarios, and hot water cannot be provided at night.

[0007] Finally, if the direct current output of the PVT system can be used directly, it will reduce the cost of converting it into alternating current and the inevitable energy loss during the conversion process, further improving energy utilization efficiency.

[0008] In summary, the existing molten salt heat storage system has problems such as large footprint, low effective space utilization, high comprehensive cost, inconvenient maintenance and updating, and low heat utilization efficiency. The quality of hot water heat source of the PVT system still needs to be further improved and the usage time limit needs to be extended. At the same time, the overall energy utilization rate of the PVT system needs to be further improved. Utility Model Content

[0009] The purpose of the utility model is to solve the above-mentioned technical problems and provide a method for fully utilizing the heat of low-temperature molten salt in the molten salt thermal storage system to make up for the problem of low quality of PVT hot water. At the same time, PVT direct current is directly introduced into the molten salt thermal storage system as a heat source, and green electricity is directly used for molten salt heat storage, thereby increasing the economy of the entire system and improving the energy utilization efficiency of the system.

[0010] In order to achieve the above-mentioned purpose, the utility model adopts the following technical scheme: a solar energy coupled molten salt heat storage steam and hot water cogeneration system, the system includes a high-temperature molten salt heat exchange tank area and a steam use area, a steam pipeline and a return water pipeline are connected between the high-temperature molten salt heat exchange tank area and the steam use area, a first water pump is connected in series on the return water pipeline, a steam spherical tank is connected to the steam pipeline through a branch pipeline, a low-temperature molten salt heat exchange tank area is connected below the high-temperature molten salt heat exchange tank area, the low-temperature molten salt heat exchange tank area is respectively connected to the hot water use area and the solar PVT system through hot water pipes, a molten salt heating area is connected below the low-temperature molten salt heat exchange tank area, a DC electric heater and a molten salt delivery pump are provided in the molten salt heating area, the molten salt delivery pump delivers the molten salt heated in the molten salt heating area to the high-temperature molten salt heat exchange tank area through the molten salt delivery pipe, and the DC electric heater is connected to the solar PVT system through a battery.

[0011] In order to make full use of the hot water in the solar PVT (solar photovoltaic / thermal technology) system and to simplify the structural construction of the system body as much as possible, the preferred technical solution includes: the water inlet port of the solar PVT system is connected to the water outlet of the third water pump through a hot water pipe, the water inlet of the third water pump is connected to the water outlet of the hot water use area through a hot water pipe and a fifth valve, the water outlet port of the solar PVT system enters the low-temperature molten salt heating area through the hot water pipe, and then is connected to the water inlet of the hot water use area after coming out of the low-temperature molten salt heating area.

[0012] In order to facilitate the convenient control of steam storage and steam discharge and use in the steam spherical tank, the preferred technical solution also includes that two branch pipelines are connected to the steam spherical tank, one branch pipeline is connected to the second air intake valve, and a straight pipeline is connected to the third exhaust valve.

[0013] In order to effectively and quickly replenish the water loss in the steam system, ensure that there is sufficient steam usage in the steam usage area, and timely and effectively replenish the steam loss caused by the steam circulation process, a further preferred technical solution also includes: a water supply pipe is provided below the steam spherical tank, and a fourth water inlet valve and a second water pump are connected in series to the water supply pipe.

[0014] In order to facilitate the control of the steam flow rate between the high-temperature molten salt heat exchange area and the steam use area, or to facilitate the control of the steam discharge time, and to facilitate the maintenance and replacement of the steam circulation system, the preferred technical solution also includes providing a first valve in the steam pipeline.

[0015] In order to facilitate the control of the flow rate and time of molten salt transportation and to facilitate the maintenance of the pipeline system, the preferred technical solution also includes providing a sixth valve on the molten salt transportation pipeline.

[0016] In order to adapt to different demands for solar power generation and hot water supply, to facilitate the processing, manufacturing, installation and maintenance of the PVT system, and to minimize the volume of the PVT system, the preferred technical solution also includes that the solar PVT system is assembled from several groups of solar panels and several solar water heaters.

[0017] In order to improve the electric heating efficiency in the molten salt heating zone and simplify the structural construction of the electric heater, a preferred technical solution also includes that the DC electric heater includes an electric heating tube heater and / or a graphene electric heater.

[0018] In order to facilitate the installation and use of the steam and hot water cogeneration system of solar energy coupled with molten salt heat storage, improve the safety performance of the system, facilitate the installation of the system, facilitate the disassembly of the system, facilitate the daily maintenance of the system, and minimize the system's footprint, the preferred technical solution also includes that the high-temperature molten salt heat exchange tank area, the low-temperature molten salt heat exchange tank area and the molten salt heating area in the system are arranged on a first support frame, the steam use area and the hot water use area are arranged on a second support frame, the steam spherical tank is arranged on a third support frame, and the solar PVT system is arranged on a fourth support frame.

[0019] In order to facilitate the processing and production of the support frame, the transportation of the support frame, and the installation and use of the system, a further preferred technical solution also includes that the first support frame, the second support frame, the third support frame, and the fourth support frame are split support frames or integral support frames.

[0020] Compared with the prior art, the beneficial effects of the utility model are as follows: the main effects of the steam and hot water cogeneration system of the solar energy coupled molten salt thermal storage PVT are embodied in the following aspects:

[0021] 1. The vertical molten salt thermal storage system improves the overall space utilization rate, and adopts a modular partition design to provide convenient replacement conditions for future maintenance and updates;

[0022] 2. The combination of the PVT system and the molten salt heat storage system not only makes perfect use of the green electricity generated by the PVT system, but also improves the power generation efficiency of the solar panels after the water passes through the PVT panels, which is conducive to delivering more heat to the molten salt heat storage system; the hot water is heated again by the low-temperature molten salt section, which improves the quality of the hot water and can be used in more application scenarios, increasing the energy utilization efficiency of the entire system and reducing costs.

[0023] 3. The molten salt heat storage part is modularized to improve the overall space utilization of the device. In the subsequent maintenance and when an accident may occur, only the components that caused the accident can be replaced, extending the life cycle of the entire system, reducing costs and investment return cycle. Adding heat exchange with water in the molten salt system increases the heat release of the molten salt and improves energy utilization.

[0024] 4. Since the hot water of the PVT system has a difficult seasonal utilization cycle, in this system, the improvement of hot water quality brought by the molten salt system has expanded the scope of hot water utilization and application scenarios, and increased the possibility of long-distance transmission. If a hot water storage tank is added, it can also be helpful. In addition, the improvement of PVT's own power generation efficiency and the efficient conversion process of directly supplying molten salt increase the overall energy utilization efficiency of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a system structure diagram of the steam and hot water cogeneration system of the utility model's solar energy coupled molten salt thermal storage PVT.

[0026] In the figure: 1. High-temperature molten salt heat exchange area; 2. Low-temperature molten salt heat exchange tank area; 3. Molten salt delivery pump; 4. Steam spherical tank; 5. Solar PVT system; 6. Steam use area; 7. Hot water use area; 8. Battery; 9. DC heater; 10. Third water pump; 11. First water pump; 12. Second water pump; 13. Molten salt heating area; 14. Steam pipeline; 15. Return water pipeline; 16. Branch pipeline; 17. Hot water pipe; 18. Molten salt delivery pipe; 19. Fifth valve; 20. Second valve; 21. Third valve; 22. Make-up water pipe; 23. Fourth valve; 24. First valve; 25. Sixth valve. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0028] A solar-coupled molten salt heat storage steam-hot water cogeneration system, the system comprising a high-temperature molten salt heat exchange tank area 1 and a steam use area 6, a steam pipeline 14 and a return water pipeline 15 are connected between the high-temperature molten salt heat exchange tank area 1 and the steam use area 6, a first water pump 11 is connected in series to the return water pipeline 15, a steam spherical tank 4 is connected to the steam pipeline 14 through a branch pipeline 16, a low-temperature molten salt heat exchange tank area 2 is connected below the high-temperature molten salt heat exchange tank area 1, the low-temperature molten salt heat exchange tank area 2 is respectively connected to the hot water use area 7 and a solar PVT system 5 through a hot water pipe 17, a molten salt heating area 13 is connected below the low-temperature molten salt heat exchange tank area, a DC heater 9 and a molten salt delivery pump 3 are provided in the molten salt heating area 13, the molten salt delivery pump 3 delivers the molten salt heated in the molten salt heating area to the high-temperature molten salt heat exchange tank area 1 through a molten salt delivery pipe 18, and the DC heater 9 is connected to the solar PVT system 5 through a battery 8.

[0029] In order to make full use of the hot water in the solar PVT system and to simplify the structural structure of the system as much as possible, the preferred implementation scheme of the utility model includes: the water inlet port of the solar PVT system 5 is connected to the water outlet of the third water pump 10 through the hot water pipe 17, the water inlet of the third water pump 10 is connected to the water outlet of the hot water use area 7 through the hot water pipe 17 and the fifth valve 19, the water outlet port of the solar PVT system 5 enters the low-temperature molten salt heating area 2 through the hot water pipe 17, and then is connected to the water inlet of the hot water use area 7 after coming out of the low-temperature molten salt heating area 2.

[0030] In order to facilitate the convenient control of steam storage and steam discharge in the steam spherical tank 4, a preferred embodiment of the utility model also includes that two branch pipelines 16 are connected to the steam spherical tank 4, one branch pipeline 16 is connected to the second air intake valve 20, and a straight pipeline 16 is connected to the third exhaust valve 21.

[0031] In order to effectively and quickly replenish the loss of water in the steam system, so that there is sufficient steam usage in the steam usage area 6, and the steam loss caused during the steam circulation process is promptly and effectively replenished, a further preferred implementation scheme of the utility model also includes that a water replenishment pipe 22 is provided below the steam spherical tank 4, and the water replenishment pipe 22 is serially connected with a fourth water inlet valve 23 and a second water pump 12.

[0032] In order to facilitate the control of the steam flow rate between the high-temperature molten salt heat exchange area 1 and the steam use area 6, or to facilitate the control of the steam discharge time, and to facilitate the maintenance and replacement of the steam circulation system, a preferred embodiment of the utility model also includes that a first valve 24 is provided in the steam pipeline 14.

[0033] In order to facilitate the control of the flow rate and time of molten salt transportation and to facilitate the maintenance of the pipeline system, a preferred technical solution also includes providing a sixth valve 25 on the molten salt transportation pipe 18 .

[0034] In order to adapt to different demands for solar power generation and hot water supply, to facilitate the processing, manufacturing, installation and maintenance of the PVT system, and to minimize the volume of the PVT system, a preferred embodiment of the utility model also includes that the solar PVT system 5 is assembled from a plurality of groups of solar panels and a plurality of solar water heaters.

[0035] In order to improve the electric heating efficiency in the molten salt heating zone 13 and simplify the structural construction of the electric heater, a preferred embodiment of the utility model also includes that the DC electric heater 9 includes an electric heating tube heater and / or a graphene electric heater.

[0036] In order to facilitate the installation and use of the steam and hot water cogeneration system of solar energy coupled with molten salt heat storage, improve the safety performance of the system, facilitate the installation of the system, facilitate the disassembly of the system, facilitate the daily maintenance of the system, and minimize the footprint of the system, the preferred implementation scheme of the utility model also includes that the high-temperature molten salt heat exchange tank area 1, the low-temperature molten salt heat exchange tank area 3 and the molten salt heating area 13 in the system are arranged on a first support frame (not shown in the figure), the steam use area 6 and the hot water use area 7 are arranged on a second support frame (not shown in the figure), the steam ball tank 4 is arranged on a third support frame (not shown in the figure), and the solar photovoltaic / water heater 5 is arranged on a fourth support frame (not shown in the figure).

[0037] In order to facilitate the processing and production of the support frame, the transportation of the support frame, and the installation and use of the system, a further preferred implementation scheme of the utility model also includes that the first support frame, the second support frame, the third support frame, and the fourth support frame are split support frames or integral support frames.

[0038] The working principle of the steam and hot water cogeneration system of the utility model solar energy coupled molten salt heat storage PVT is:

[0039] In the high-temperature molten salt heat exchange area 1, the high-temperature molten salt pumped out by the molten salt pump exchanges heat with the water sent by the first water pump 11 in this area to generate steam. The steam is stored in the steam spherical tank 4. When needed, the steam is output from the steam spherical tank 4 to the steam use area 6. After a round of heat exchange, the temperature of the molten salt is reduced, and it enters the low-temperature heat exchange area 2 for further heat exchange with the low-temperature hot water preheated by the PVT system 5 plate to improve the quality of the hot water. The hot water with improved quality is transported to the hot water use area 7 for use. After another heat exchange, the molten salt is heated in the heating area 13 using the DC electric heater 9 emitted by the PVT system 5. The molten salt delivery pumping area 13 that reaches the set heating temperature is transported by the molten salt delivery pump 3 to the high-temperature molten salt heat exchange area 1, completing a cycle of the molten salt. The steam spherical tank 4 is connected to the water replenishment pump 12, thereby performing a water replenishment operation. The water circulation of the PVT system 5 comes from the water in the hot water use area 7 and is sent to the panels of the PVT system 5 through the third water pump 10. The electric energy generated by the PVT system 5 is stored to a certain extent by the battery 8, which has adapted to the power generation and storage in the scene of temporary non-heating, and can also meet the output of stable direct current for molten salt heating.

[0040] This system makes full use of the heat of low-temperature molten salt in molten salt heat storage to compensate for the low quality of hot water in PVT system 5. At the same time, the direct current of PVT system 5 is directly introduced into the molten salt heat storage system as a heat source, and green electricity is directly used for molten salt heat storage, which increases the economy of the entire system and improves the energy utilization efficiency of the system.

[0041] 1. The molten salt heat storage system has a compact design and uses less molten salt, which reduces the cost of the entire molten salt system and improves the flexibility of the system.

[0042] 2. Molten salt system 2-Low-temperature heat exchange zone increases the heat exchange capacity of the molten salt system, increases the types of energy output forms of the molten salt system, and increases its applicable usage scenarios.

[0043] 3. The direct current output of the PVT system is directly used to heat the molten salt, which reduces the cost and energy loss caused by the conversion and utilization of power generation in the conventional PVT system. At the same time, PVT utilizes the 2-low-temperature heat exchange zone of the molten salt system to improve the quality of its output hot water.

[0044] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes within the technical scope disclosed by the present invention according to the technical scheme and the utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A solar-coupled molten salt thermal storage steam and hot water cogeneration system, characterized in that: The system comprises a high-temperature molten salt heat exchange tank area and a steam use area, wherein a steam pipeline and a return water pipeline are connected between the high-temperature molten salt heat exchange tank area and the steam use area, a first water pump is connected in series on the return water pipeline, a steam spherical tank is connected on the steam pipeline through a branch pipeline, a low-temperature molten salt heat exchange tank area is connected below the high-temperature molten salt heat exchange tank area, the low-temperature molten salt heat exchange tank area is respectively connected to the hot water use area and the solar PVT system through hot water pipes, a molten salt heating area is connected below the low-temperature molten salt heat exchange tank area, a direct current electric heater and a molten salt delivery pump are arranged in the molten salt heating area, the molten salt delivery pump delivers the molten salt heated in the molten salt heating area to the high-temperature molten salt heat exchange tank area through the molten salt delivery pipe, and the direct current electric heater is connected to the solar PVT system through a battery.

2. The solar energy coupled molten salt thermal storage steam and hot water cogeneration system according to claim 1, characterized in that: The water inlet port of the solar PVT system is connected to the water outlet of the third water pump through a hot water pipe, and the water inlet of the third water pump is connected to the water outlet of the hot water usage area through a hot water pipe and a fifth valve. The water outlet port of the solar PVT system enters the low-temperature molten salt heating area through a hot water pipe, and then comes out of the low-temperature molten salt heating area and is connected to the water inlet of the hot water usage area.

3. The solar energy coupled molten salt thermal storage steam and hot water cogeneration system according to claim 1, characterized in that: Two branch pipelines are connected to the steam spherical tank, one branch pipeline is connected to a second air intake valve, and a straight pipeline is connected to a third exhaust valve.

4. The solar energy coupled molten salt thermal storage steam and hot water cogeneration system as claimed in claim 3, characterized in that: A water supply pipe is provided below the steam spherical tank, and a fourth water inlet valve and a second water pump are connected in series to the water supply pipe.

5. The solar energy coupled molten salt thermal storage steam and hot water cogeneration system according to claim 1, characterized in that: A first valve is provided on the steam pipeline.

6. The solar energy coupled molten salt thermal storage steam and hot water cogeneration system according to claim 1, characterized in that: A sixth valve is provided on the molten salt delivery pipeline.

7. The solar energy coupled molten salt thermal storage steam and hot water cogeneration system as claimed in claim 2, characterized in that: The solar PVT system is assembled from a plurality of solar panels and a plurality of Sun Dream water heaters.

8. The solar energy coupled molten salt thermal storage steam and hot water cogeneration system according to claim 1, characterized in that: The DC electric heater includes an electric heating tube heater and / or a graphene electric heater.

9. The solar energy coupled molten salt thermal storage steam and hot water cogeneration system according to claim 1, characterized in that: The high-temperature molten salt heat exchange tank area, low-temperature molten salt heat exchange tank area and molten salt heating area in the system are arranged on the first support frame, the steam use area and hot water use area are arranged on the second support frame, the steam spherical tank is arranged on the third support frame, and the solar photovoltaic / water heater solar PVT system is arranged on the fourth support frame.

10. The solar energy coupled molten salt thermal storage steam and hot water cogeneration system as claimed in claim 9, characterized in that: The first support frame, the second support frame, the third support frame and the fourth support frame are split support frames or integral support frames.

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