A solar drying system based on phase change energy storage and waste heat recovery

Abstract

The present invention discloses a solar drying system based on phase change energy storage and waste heat recovery, which includes a drying chamber, a phase change energy storage module, a solar heat collection module, a heat exchanger and a waste heat recovery module. The present invention utilizes a phase change energy storage wall to achieve heat collection and energy storage, so that the system can achieve continuous drying during the day and at night; by designing a brand-new structure, the waste heat of the humid and hot air after drying is recovered, so that the system has higher energy utilization efficiency; at the same time, the opposite hot air circulation directions during the day and at night are beneficial to the uniform drying of materials; it can effectively improve the comprehensive utilization rate of solar energy, save resources, and the energy supply is stable and sustainable, reduce environmental pollution, and also avoid problems such as the reduction of the quality of agricultural products caused by manual drying, and has good economic benefits.

Description

Technical Field

[0001] The present invention relates to the field of new energy technologies, and more particularly to a solar drying system based on phase change energy storage and waste heat recovery. Background Art

[0002] At present, in order to seek energy security and the sustainable development of human society, countries around the world are actively researching and developing renewable energy. As one of the renewable energy sources that are inexhaustible, inexhaustible, and pollution-free, solar energy is being emphasized and utilized by various industries. For coastal islands, grassland pastoral areas, mountainous areas, and plateau areas that lack water, fuel, and have inconvenient transportation, it is very suitable and promising to utilize solar energy according to local conditions. At present, the solar thermal utilization technology in China is developing rapidly, and the extensive use of new energy technologies in certain regions is of great significance for the adjustment of China's energy structure.

[0003] Traditional drying usually adopts the method of open-air natural drying, which has many drawbacks: low efficiency, large floor area, time-consuming and laborious, vulnerable to climate conditions such as showers and plum rains, and also vulnerable to pollution by sand, dust, insects, etc., making it difficult to guarantee the quality of dried food or agricultural and sideline products. The artificial drying industry is an industry with high energy consumption. In developed countries, about 20% of fossil fuels are used for drying. Relying on the heat provided by fossil fuels, on the one hand, it causes serious environmental pollution, and on the other hand, it is difficult to guarantee the quality of the dried food or agricultural and sideline products and is prone to secondary pollution.

[0004] At present, governments of various countries have regarded the utilization of solar energy resources as an important part of the national sustainable development strategy. Solar drying devices conform to the development of low-carbon economy, are sustainable, energy-saving and emission-reducing products, and are an opportunity for the development of the solar energy industry. The solar energy industry has a huge scale and great potential for market development. Enterprises will pay more attention to improving the quality of products. Whether from the perspective of energy conservation or environmental protection, actively developing new energy and improving the thermal energy utilization rate is an inevitable trend in the development of the green drying industry. However, because solar energy is intermittent and unstable, it will cause the system to be unable to provide energy in time and make it unable to work normally. Therefore, it is an urgent situation to combine solar thermal utilization technology with energy storage technology to achieve complementary advantages and continuous operation day and night. Summary of the Invention

[0005] In view of this, the present invention provides a solar drying system based on phase change energy storage and waste heat recovery, which combines solar energy and phase change energy storage to provide energy, can effectively improve the comprehensive utilization rate of solar energy, save resources, maintain stable energy supply, reduce environmental pollution, and at the same time avoid problems such as the reduction of the quality of agricultural products caused by artificial drying.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A solar drying system based on phase change energy storage and waste heat recovery, comprising a drying box, a phase change energy storage module, a solar heat collection module and a heat exchanger;

[0008] The top of the drying box is provided with a first ventilation opening, the bottom is provided with a second ventilation opening, and the bottom of the side wall is provided with a third ventilation opening. The first ventilation opening is connected with a ventilation pipe, and the third ventilation opening is connected with a collector ventilation pipe;

[0009] The phase change energy storage module is installed on the side wall of the drying box, and includes a transparent cover plate, a phase change energy storage box and a heat insulation layer arranged in sequence from outside to inside. A heat conduction copper pipe penetrates through the center of the phase change energy storage box from top to bottom. The top end of the heat conduction copper pipe is communicated with the ventilation pipe, the bottom end is provided with an air inlet baffle, and an air outlet one and a dual-control baffle one are arranged at the connection between the ventilation pipe and the heat conduction copper pipe;

[0010] The solar heat collection module includes a collector, and a heat collection air pipe penetrates through the collector. The end of the heat collection air pipe is connected with the collector ventilation pipe;

[0011] An air inlet is arranged at the bottom end of the collector ventilation pipe;

[0012] The heat exchanger is provided with a first air outlet, a second air outlet, a third air outlet and a fourth air outlet. The first air outlet is connected with the second ventilation opening, and the second air outlet is communicated with the air inlet;

[0013] A dual-control baffle two is arranged between the third ventilation opening and the first air outlet.

[0014] Further, it further includes a waste heat recovery module. The waste heat recovery module is a phase change energy storage device coated on the outer wall of the ventilation pipe, and the phase change material inside undergoes a phase change at a phase change temperature of 50°C.

[0015] Further, a variable-frequency fan is installed at the first ventilation opening, a frequency modulation switch is installed on the drying box, and the variable-frequency fan is electrically connected with the frequency modulation switch.

[0016] Further, a temperature sensor is arranged in the drying box, and the temperature sensor is electrically connected with the frequency modulation switch.

[0017] Further, a circulation fan is arranged at the third ventilation opening.

[0018] Further, the transparent cover plate is a glass cover plate.

[0019] Further, the phase change energy storage box is a sun-dried type energy storage collector, and heat insulation layers are arranged at both the top and the bottom. The phase change material filled therein is a phase change material that undergoes a phase change at 130°C, and the heat conduction copper pipe is an inner finned heat conduction copper pipe.

[0020] Furthermore, a bracket is installed at the bottom of the drying oven, and a step is provided on one side of the bracket where the drying oven door is located.

[0021] Furthermore, the solar heat collection module is placed on a tripod.

[0022] Furthermore, a number of parallel placement plates are arranged inside the drying oven.

[0023] As can be seen from the above technical solutions, compared with the prior art, the present invention discloses a solar drying system based on phase change energy storage and waste heat recovery, which has the following beneficial effects:

[0024] Phase change energy storage utilizes solar energy to achieve continuous operation of the drying system. Two opposite hot air circulation directions are adopted to achieve the purpose of uniform drying. The integrated design of the energy storage wall and the drying oven saves space. The energy of the wet air discharged from the drying oven is recycled in a cascaded manner by using the phase change energy storage device and the heat exchanger. Alternate drying during the day and at night is carried out to continuously dry the materials and reduce the drying cycle. By using a sun-basking type energy storage collector as the energy storage wall, the temperature inside is very high, and the phase change material adopted has a greater heat storage capacity to meet the demand for night drying. By automatically sensing the temperature change inside the drying oven and then changing the rotational speed of the variable-frequency fan, the effect of reaching the ideal drying temperature is achieved. The use of internal finned heat-conducting copper tubes increases the heat exchange efficiency between the energy storage material and the hot air. The use of a solar collector to heat air saves resources, and it is an ideal drying system. Description of the Drawings

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0026] Figure 1 It is the overall structure diagram of a solar drying system based on phase change energy storage and waste heat recovery provided by an embodiment of the present invention. Detailed Embodiments

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0028] As shown in the atta Figure 1As described above, a solar drying system based on phase change energy storage and waste heat recovery includes a drying box 1, a phase change energy storage module, a solar heat collection module, and a heat exchanger 4;

[0029] The top of the drying box 1 has a first ventilation opening 11, the bottom has a second ventilation opening 12, and the bottom of the side wall has a third ventilation opening 13. The first ventilation opening 11 is connected to a ventilation pipe 5, and a variable frequency fan 7 is installed at the first ventilation opening 11. The third ventilation opening 13 is connected to a collector ventilation pipe 6, and a circulation fan 8 is provided at the third ventilation opening 13;

[0030] The phase change energy storage module is installed on the side wall of the drying box 1 and includes a transparent cover plate 21, a phase change energy storage box 22, and a heat insulation layer 23 arranged from outside to inside in sequence. A heat conduction copper pipe 24 penetrates through the center of the phase change energy storage box 22 from top to bottom. The top end of the heat conduction copper pipe 24 is communicated with the ventilation pipe 5, the bottom end has an air inlet baffle 241, and an air outlet 25 and a dual-mode baffle 26 are provided at the connection between the ventilation pipe 5 and the heat conduction copper pipe 24;

[0031] The solar heat collection module includes a collector 3, and a heat collection air pipe 31 penetrates through the collector 3. The end of the heat collection air pipe 31 is connected to the collector ventilation pipe 6;

[0032] An air inlet 61 is provided at the bottom end of the collector ventilation pipe 6;

[0033] The heat exchanger 4 is provided with a first air outlet 41, a second air outlet 42, a third air outlet 43, and a fourth air outlet 44. The first air outlet 41 is connected to the second ventilation opening 12, and the second air outlet 42 is communicated with the air inlet 61;

[0034] A dual-mode baffle 45 is provided between the third ventilation opening 13 and the first air outlet 41.

[0035] It further includes a waste heat recovery module, and the waste heat recovery module is a phase change energy storage device 51 coated on the outer wall of the ventilation pipe 5, and the phase change material inside undergoes a phase change at a phase change temperature of 50°C.

[0036] The working principle of the above technical solution is:

[0037] During daytime operation: The double-sided baffle one 26 is turned to the heat-conducting copper tube 24, and the double-sided baffle two 45 is turned to the air vent two 12; The circulation fan 8 is turned on, and the variable-frequency fan 7 is turned on and rotates forward; The collector 3 absorbs solar energy to heat the air, and the phase-change energy storage box 22 with an absorption coating absorbs solar energy for energy storage; Outdoor air enters the collector 3 through the air inlet of the heat-collecting air duct 31 for heating. The heated air flows through the collector ventilation duct 6 under the action of the circulation fan 8 and enters the drying oven 1 to dry the material. The dried wet air flows through the phase-change energy storage device 51 through the ventilation duct 5 under the action of the variable-frequency fan 7. The phase-change energy storage device 51 absorbs the waste heat for energy storage, and the wet air after heat recovery flows out of the system through the air outlet one 25.

[0038] During nighttime operation: The double-sided baffle one 26 is turned to the air outlet one 25, the double-sided baffle two 45 is turned to the phase-change energy storage module, and the air inlet baffle 241 of the heat-conducting copper tube 24 is opened; The circulation fan 8 is turned on, and the variable-frequency fan 7 is turned on and rotates in reverse; The phase-change energy storage box 22 with an absorption coating releases energy and transfers it to the heat-conducting copper tube 24 for air heating; Outdoor air enters the collector ventilation duct 6 through the air vent two 42 and the air inlet of the heat-collecting air duct 31, enters the heat-conducting copper tube 24 under the action of the circulation fan 8. The energy released by the phase-change energy storage box 22 with an absorption coating heats the air. The hot air enters the phase-change energy storage device 51 through the ventilation duct 5. The phase-change energy storage device 51 replenishes energy to the hot air. The hot air after energy replenishment enters the drying oven 1 under the reverse blowing of the variable-frequency fan 7 to dry the material. The dried wet air enters the heat exchanger 4 through the air vent two 12 and exchanges heat crosswise with the fresh air entering the heat exchanger 4 through the air vent three 43 of the heat exchanger 4. The wet air after heat exchange flows out of the system through the air vent four 44 of the heat exchanger 4.

[0039] As shown in the Figure 1 accompanying figure, in some improved specific technical solutions, a frequency modulation switch 14 is installed on the drying oven 1, and the variable-frequency fan 7 is electrically connected to the frequency modulation switch 14.

[0040] As shown in the Figure 1 accompanying figure, in some improved specific technical solutions, a temperature sensor 15 is arranged inside the drying oven 1, and the temperature sensor 15 is electrically connected to the frequency modulation switch 14.

[0041] During the drying process, the temperature sensor 15 is connected to the frequency modulation switch 14. By sensing the temperature change inside the drying oven 1, the rotation speed of the variable-frequency fan 7 is adjusted to change the hot air flow rate, thereby changing the temperature inside the drying oven 1.

[0042] As shown in the Figure 1 accompanying figure, in some improved specific technical solutions, the transparent cover plate 21 is a glass cover plate, which does not affect the absorption and utilization of light energy and has a relatively low cost.

[0043] As shown in the appendix Figure 1 As shown, in some improved specific technical solutions, the phase change energy storage box 22 is a solar heat collection device with heat insulation on both the top and bottom. The phase change material filled therein is a phase change material that undergoes a phase change at 130 °C. The heat conducting copper tube 24 is an inner finned heat conducting copper tube, and the fins increase the contact conduction area, which is beneficial to heat transfer.

[0044] As shown in the appendix Figure 1 As shown, in some improved specific technical solutions, a bracket 16 is installed at the bottom of the drying box 1, and a step 17 is provided on one side of the door of the bracket 16 located in the drying box 1.

[0045] As shown in the appendix Figure 1 As shown, in some improved specific technical solutions, the solar heat collection module is placed on the tripod 9, and the tripod is used to support it so that it faces the light source for irradiation, achieving the maximum solar energy utilization rate.

[0046] As shown in the appendix Figure 1 As shown, in some improved specific technical solutions, a number of parallel object placement plates 18 are provided in the drying box 1.

[0047] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. For the same or similar parts among the embodiments, reference can be made to each other. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple. For related parts, reference can be made to the description in the method section.

[0048] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A solar drying system based on phase change energy storage and waste heat recovery, characterized in that, It includes a drying oven, a phase change energy storage module, a solar heat collection module and a heat exchanger; The top of the drying oven has a first ventilation opening, the bottom has a second ventilation opening, and the bottom of the side wall has a third ventilation opening. The first ventilation opening is connected to a ventilation pipe, and the third ventilation opening is connected to a collector ventilation pipe; The phase change energy storage module is installed on the side wall of the drying oven and includes a transparent cover plate, a phase change energy storage box, and a heat insulation layer arranged from outside to inside in sequence. A heat conduction copper pipe penetrates through the center of the phase change energy storage box from top to bottom. The top of the heat conduction copper pipe is communicated with the ventilation pipe, and the bottom end has an air inlet baffle. An air outlet one and a dual control baffle one are provided at the connection of the ventilation pipe and the heat conduction copper pipe; The solar heat collection module includes a collector, and a heat collection air pipe penetrates through the collector. The end of the heat collection air pipe is connected to the collector ventilation pipe; An air inlet is provided at the bottom end of the collector ventilation pipe; The heat exchanger is provided with a first air outlet, a second air outlet, a third air outlet and a fourth air outlet. The first air outlet is connected to the second ventilation opening, and the second air outlet is communicated with the air inlet; A dual control baffle two is provided between the third ventilation opening and the first air outlet; 2. The solar drying system based on phase change energy storage and waste heat recovery according to claim 1, characterized in that, It further includes a waste heat recovery module, and the waste heat recovery module is a phase change energy storage device coated on the outer wall of the ventilation pipe; 3. The solar drying system based on phase change energy storage and waste heat recovery according to claim 1, characterized in that, A variable frequency fan is installed at the first ventilation opening, a frequency modulation switch is installed on the drying oven, and the variable frequency fan is electrically connected to the frequency modulation switch; 4. The solar drying system based on phase change energy storage and waste heat recovery according to claim 3, characterized in that, A temperature sensor is arranged inside the drying oven, and the temperature sensor is electrically connected to the frequency modulation switch; 5. The solar drying system based on phase change energy storage and waste heat recovery according to claim 1, characterized in that, A circulation fan is arranged at the third ventilation opening; 6. The solar drying system based on phase change energy storage and waste heat recovery according to claim 1, characterized in that, The transparent cover plate is a glass cover plate; 7. The solar drying system based on phase change energy storage and waste heat recovery according to claim 1, characterized in that, The phase change energy storage box is a sun-baked type energy storage collector, and the heat conduction copper pipe is an internal fin heat conduction copper pipe; 8. The solar drying system based on phase change energy storage and waste heat recovery according to claim 1, characterized in that, A bracket is installed at the bottom of the drying oven, and a step is arranged on one side of the bracket where the drying oven door is located; 9. The solar drying system based on phase change energy storage and waste heat recovery according to claim 1, characterized in that, The solar heat collection module is placed on a tripod; 10. The solar drying system based on phase change energy storage and waste heat recovery according to claim 1, characterized in that, A number of parallel object placing plates are arranged inside the drying oven.

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