A solar heat exchange device and method

Abstract

This invention provides a solar heat exchange device and method. The solar heat exchange device includes a solar collector connected to a water tank and a shell-and-tube heat exchanger. The solar collector converts collected solar energy into heat energy to heat the water in the water tank and the shell-and-tube heat exchanger. The solar collector has copper fins of varying heights distributed within the water tank to improve the heating rate of the water. The solar collector heats the water in the tank and the shell-and-tube heat exchanger. The high-temperature steam generated after the water in the tank evaporates is first heated and then enters the shell-and-tube heat exchanger through an air duct for secondary heating. After temperature regulation by a distribution valve, hot air at the required temperature is discharged through an outlet pipe. The solar heat exchange device of this invention effectively utilizes solar energy to solve the problem of insufficient hot air temperature in existing heat exchange devices, leading to low drying efficiency, and also reduces environmental pollution.

Description

Technical Field

[0001] This invention relates to the field of solar heat exchange technology, and more particularly to a solar heat exchange device and method. Background Technology

[0002] With the continuous advancement of technology, the use of solar energy to dry crops has gradually come into view. However, most current solar drying technologies directly convert solar energy into hot air, which has low solar energy utilization efficiency and struggles to reach the required hot air temperature for drying crops. A heat pump is often needed for auxiliary heating to achieve the desired drying temperature. Currently, the mainstream dryers on the market are still traditional dryers, and the high demand for non-renewable energy sources inevitably leads to environmental pollution.

[0003] Therefore, there is a need for a heat exchange device that can utilize renewable energy, reduce environmental pollution, and ensure high drying temperatures for efficient drying of crops. Summary of the Invention

[0004] The main objective of this invention is to provide a solar heat exchange device and method that can solve the problems of insufficient air temperature when using solar energy for drying, resulting in low drying efficiency and the inability to utilize renewable energy sources, which would cause significant environmental pollution.

[0005] To achieve the above objectives, a first aspect of the present invention provides a solar heat exchange device, comprising:

[0006] A solar collector connects a water tank and a shell-and-tube heat exchanger. The solar collector converts collected solar energy into heat energy to heat the water in the water tank and the shell-and-tube heat exchanger. The solar collector has copper fins of varying heights distributed within the water tank to improve the heating rate of the water in the tank.

[0007] Furthermore, the solar collector is located at the bottom of the water tank, and the upper wall of the water tank has multiple vent holes for discharging water vapor from the water tank. The side wall of the water tank has a water tank inlet, a water tank outlet, and a condensate return outlet. The water in the water tank is used to reduce the temperature of the solar collector.

[0008] Furthermore, the solar heat exchange device also includes a tubular heat exchanger made of copper tubing. The tubular heat exchanger is located in the first heating chamber, which is connected to the air inlet pipe and the air duct. The bottom of the tubular heat exchanger is connected to a circular hole on the upper wall of the water tank, and the upper end of the tubular heat exchanger is connected to the steam chamber. The water vapor generated in the water tank enters the steam chamber through the tubular heat exchanger to raise the temperature of the tubular heat exchanger and heat the natural air in the first heating chamber.

[0009] Furthermore, the solar heat exchange device also includes a steam chamber. The bottom of the steam chamber is provided with multiple circular holes that communicate with the tubular heat exchanger. The circular holes are used to discharge the water vapor generated in the water tank into the steam chamber. The top of the steam chamber is connected to a safety pipe. The safety pipe is equipped with a safety valve. The safety valve is normally closed. When the pressure in the steam chamber exceeds the set value of the safety valve, the safety valve will open and discharge the water vapor in the steam chamber through the safety pipe.

[0010] Furthermore, a steam pipe is connected to the top of the steam chamber, which is used to discharge the water vapor in the steam chamber after energy recovery; a pressure valve is installed in the steam pipe, which is used to control the discharge speed of the water vapor in the steam pipe; the steam pipe passes through a vane pump, which is powered by the high-pressure water vapor in the steam pipe.

[0011] Furthermore, a condensing device is connected to the side of the steam pipe away from the vane pump; the condensing device is provided with a condensing device water inlet, which is used to inject cold water into the condensing device; the high-temperature steam in the steam pipe will exchange heat with the cold water in the condensing device when passing through the condensing section, turning the high-temperature steam into condensate.

[0012] Furthermore, a first condensate return pipe is installed after the condensation section of the steam pipe, and a second condensate return pipe is installed at the bottom of the outer side of the steam chamber. Both the first condensate return pipe and the second condensate return pipe are connected to the water tank.

[0013] Furthermore, the first heating chamber is also connected to an air inlet duct, which has two air inlets, each equipped with a first induced draft fan and a second induced draft fan. The first induced draft fan is used to draw cold air from nature into the air inlet duct. The second induced draft fan is connected to a vane pump, and the two are connected by a transmission belt to transmit power. The first induced draft fan is powered by a solar panel and is used to assist in induced draft when the power of the second induced draft fan is insufficient.

[0014] Furthermore, the air duct is also connected to the second heating chamber, which is equipped with a shell-and-tube heat exchanger. The shell-and-tube heat exchanger has fins inside, which are used to fully heat the hot air passing through the first heating chamber.

[0015] Furthermore, a reflector is installed above the second heating chamber, and an array of convex lenses is installed on the top of the reflector. The array of convex lenses has two degrees of freedom, and the inner side of the reflector is a plane mirror. The angle of the array of convex lenses is adjusted so that sunlight is focused onto the glass at the top of the shell-and-tube heat exchanger.

[0016] Furthermore, the solar heat exchange device also includes an air outlet duct and a gas distribution duct. The second heating chamber is connected to the air outlet duct, and the air outlet duct is connected to the gas distribution duct. A gas distribution valve is installed inside the air outlet duct to regulate the temperature inside the air outlet duct. A gas distribution fan is installed on the side of the gas distribution duct away from the air outlet duct, and a downwardly inclined baffle is installed inside the gas distribution duct.

[0017] Furthermore, a frame is connected to the bottom of the solar collector, and the frame is used to adjust the height of the solar heat exchange device.

[0018] A second aspect of the present invention provides a solar heat exchange method, based on the solar heat exchange device described in any one of the preceding claims, the method comprising:

[0019] The solar collector is controlled to heat the water in the tank to generate high-temperature steam.

[0020] The high-temperature steam flows through the tubular heat exchanger to raise the temperature of the tubular heat exchanger. The tubular heat exchanger heats the air in the first heating chamber once to obtain air after one heating.

[0021] An array of convex lenses focuses sunlight onto the glass above the shell-and-tube heat exchanger to heat the shell-and-tube heat exchanger, which then reheats the air after the first heating to obtain reheated air.

[0022] The air, after secondary heating, is discharged into the heat exchange device through the air outlet duct to dry the crops.

[0023] Applying the technical solution of this invention, the solar collector converts solar energy into thermal energy to heat the water in the tank and the shell-and-tube heat exchanger. After the water in the tank boils, it produces high-temperature steam. The high-temperature steam flows through the shell-and-tube heat exchanger, raising its temperature. The steam then enters the steam chamber, where a steam pipe at the top creates high pressure. A vane pump inside the steam pipe converts the kinetic energy of the high-pressure steam into mechanical energy to power the second induced draft fan. A condensing device outside the steam pipe condenses the steam into condensate, achieving heat recycling. The induced draft fan of the air inlet device draws air from the environment into the first heating chamber for heat exchange with the shell-and-tube heat exchanger. The heated air then enters the second heating chamber through a duct, where the shell-and-tube heat exchanger further heats the air, raising its temperature. After the temperature is adjusted by the air distribution valve to reach the required temperature for drying crops, the air is discharged into the heat exchange device through the outlet pipe to dry the crops. An array of convex lenses above the shell-and-tube heat exchanger can further maximize the use of solar energy and reduce environmental pollution. Attached Figure Description

[0024] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0025] Figure 1 A schematic diagram of the overall structure of the solar heat exchanger of the present invention is shown.

[0026] Figure 2 A schematic diagram of the solar collector of the solar heat exchange device of the present invention is shown;

[0027] Figure 3 A schematic diagram of the water tank structure of the solar heat exchanger of the present invention is shown;

[0028] Figure 4 A schematic diagram of the first heating chamber structure of the solar heat exchanger of the present invention is shown;

[0029] Figure 5 A schematic diagram of the steam chamber structure of the solar heat exchanger of the present invention is shown;

[0030] Figure 6 A schematic diagram of the steam pipe structure of the solar heat exchanger of the present invention is shown;

[0031] Figure 7 A schematic diagram of the air inlet duct structure of the solar heat exchanger of the present invention is shown;

[0032] Figure 8 A schematic diagram of the drive belt structure of the solar heat exchanger of the present invention is shown;

[0033] Figure 9 A schematic diagram of the reflector structure of the solar heat exchanger of the present invention is shown;

[0034] Figure 10 A schematic diagram of the air outlet duct structure of the solar heat exchanger of the present invention is shown;

[0035] Figure 11 A simulation model diagram of fluid heat transfer in the solar heat exchange device of the present invention is shown when the wind speed is 0.5 m / s;

[0036] Figure 12 A simulation model diagram of fluid heat transfer in the solar heat exchange device of the present invention is shown when the wind speed is 1.0 m / s;

[0037] Figure 13 A simulation model diagram of fluid heat transfer in the solar heat exchange device of the present invention is shown when the wind speed is 1.5 m / s;

[0038] Figure 14 A schematic diagram of the temperature measurement points of the solar heat exchanger of the present invention is shown;

[0039] Figure 15 The diagram shows the temperature changes at various points of the solar heat exchanger at different wind speeds according to the present invention.

[0040] Figure 16 A flowchart of the solar heat exchange method of the present invention is shown.

[0041] The above figures include the following reference numerals:

[0042] 1. Frame; 2. Solar collector; 3. Water tank; 4. First heating chamber; 5. Condensation unit drain pipe; 6. Air inlet pipe; 7. First induced draft fan; 8. Condensation unit; 9. Second induced draft fan; 10. Steam pipe; 11. Vane pump; 12. Safety pipe; 13. Air duct; 14. Array convex lens; 15. Reflector; 16. Second heating chamber; 17. Gas distribution induced draft fan; 18. Gas distribution valve; 19. Air outlet pipe; 20. Copper sheet; 21. Shell and tube heat exchanger; 22. Glass; 23. Fins; 24. Water tank outlet; 25. Water tank inlet; 26. Water tank upper wall; 27. Condensate return port; 28. Condensate... 29. Drain pipe connection port; 30. Air inlet; 31. Tubular heat exchanger; 32. Steam chamber bottom plate; 33. Steam chamber; 34. Steam chamber return port; 35. Pressure valve; 36. Safety valve; 37. First condensate return pipe; 38. Baffle plate; 39. Air outlet; 40. Plane mirror; 41. First fixed shaft; 42. Second fixed shaft; 43. Second induced draft fan shaft; 44. Worm gear; 45. Turbine; 46. Protective shell; 47. Small pulley shaft; 48. Large pulley; 49. Small pulley; 50. Conveyor belt; 51. Large pulley shaft; 52. Vane pump fan; 53. Second condensate return pipe; 54. Condensation device water inlet. Detailed Implementation

[0043] Preferred embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While preferred embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0044] Example 1

[0045] See also Figures 1 to 3 As shown, the present invention provides a solar heat exchange device, including a solar collector 2, which is connected to a water tank 3 and a shell-and-tube heat exchanger 21. It can heat the water in the water tank 3 and the shell-and-tube heat exchanger 21. Since copper has a high thermal conductivity, copper is used as the main component of the solar collector 2. In addition, the solar collector 2 is provided with alternating high and low copper plates 20 at the water tank 3, which can improve the heating rate of the water in the water tank 3.

[0046] See also Figures 2 to 3As shown, in one embodiment of the present invention, the bottom of the water tank 3 is a solar collector 2. The water tank 3 is made of a material with heat-insulating effect. The upper wall 26 of the water tank has multiple round holes for discharging the high-temperature water vapor generated after the water in the water tank 3 evaporates. The side wall of the water tank is provided with a water tank inlet 25, a water tank outlet 24, and a condensate return outlet 27. The water tank inlet 25 is connected to a water pipe for filling the water tank 3 with water, and the water tank outlet 24 is used to discharge the water in the water tank 3. Since the solar collector 2 is provided at the bottom of the water tank, the water in the water tank 3 can be heated by the solar collector 2 to generate high-temperature water vapor. The water in the water tank 3 can also be used to reduce the temperature of the solar collector 2, preventing the solar collector 2 from being damaged due to excessive temperature.

[0047] In this embodiment, the water tank 3 also includes a first water level sensor, a second water level sensor, and a temperature sensor. The height of the first water level sensor is greater than the height of the second water level sensor. The first and second water level sensors are used to detect the water depth in the water tank 3 in real time. When the water level is lower than that of the second water level sensor, the water tank inlet 25 will open, and water will begin to be added to the water tank 3. When the water level is higher than that of the first water level sensor, the water tank inlet 25 will close, and water addition will stop. The temperature sensor is used to detect the temperature of the water in the water tank 3.

[0048] See also Figure 4 As shown, in one embodiment of the present invention, the solar heat exchange device further includes a first heating chamber 4, which contains a tubular heat exchanger 30 made of copper tubing. The first heating chamber 4 is connected to the air inlet pipe 6 and the air duct 13. The bottom of the tubular heat exchanger 30 is connected to a round hole in the upper wall 26 of the water tank, and the upper end of the tubular heat exchanger 30 is connected to the bottom plate 31 of the steam chamber. The high-temperature steam generated in the water tank 3 enters the steam chamber 32 through the tubular heat exchanger 30. The high-temperature steam can heat the tubular heat exchanger 30, thereby achieving a primary heating of the natural cold air discharged into the first heating chamber 4 from the air inlet pipe 6. The heated air then flows into the air duct 13.

[0049] In this embodiment, the first heating chamber 4 has shells made of heat-insulating material on both sides to prevent heat loss from the first heating chamber 4.

[0050] See also Figures 4 to 6As shown, in one embodiment of the present invention, the solar heat exchange device further includes a steam chamber 32. The bottom plate 31 of the steam chamber has multiple round holes that are connected to the tubular heat exchanger 30 to discharge the high-temperature water vapor generated in the water tank into the steam chamber 32. Therefore, a high-pressure environment is formed in the steam chamber 32. The top of the steam chamber 32 is connected to the steam pipe 10 and the safety pipe 12. The safety pipe 12 is equipped with a safety valve 35. The safety valve 35 is normally closed. When the pressure in the steam chamber 32 exceeds the set value of the safety valve 35, the safety valve 35 will open and discharge the water vapor in the steam chamber 32 through the safety pipe 12.

[0051] In this embodiment, the steam chamber 32 also includes a temperature sensor and a pressure sensor. The temperature sensor is used to detect the temperature of the water vapor inside the steam chamber 32, and the pressure sensor is used to detect the pressure inside the steam chamber 32.

[0052] In this embodiment, the steam pipe 10 is located at the top of the steam chamber 32, and is used to discharge the sub-high temperature steam in the steam chamber 32 into nature after energy recovery, thereby realizing the recycling of energy. The steam pipe 10 is equipped with a pressure valve 34 and a vane pump 11. The pressure valve 34 is used to control the discharge speed of the steam in the steam pipe 10. The vane pump 11 is powered by the high-pressure steam in the steam pipe 10. The high-pressure steam blows the vane pump fan 51, thereby driving the vane pump 11 to rotate, and thus converting the kinetic energy of the steam into the mechanical energy of the vane pump 11.

[0053] In this embodiment, a condenser 8 is also installed on the outside of the steam pipe 10. The bottom of the condenser 8 has a water inlet 53 for injecting cold water into the condenser 8. Designing the water inlet 53 at the bottom of the condenser 8 ensures that the condenser 8 is completely filled with cold water, so that the steam pipe 10 is fully cooled. When the sub-high temperature steam in the steam pipe 10 passes through the condensation section, it will exchange heat with the cold water in the condenser 8, thereby reducing the temperature of the sub-high temperature steam and turning it into condensate. At the same time, the cold water in the condenser 8 will be heated to achieve heat recycling. The upper end of the condenser 8 has a drain outlet, which is connected to the water tank through the condenser drain pipe 5 for draining the heated water in the condenser 8 into the water tank 3. This can increase the boiling rate of the water in the water tank 3 and achieve water recycling.

[0054] In this embodiment, the first condensate return pipe 36 is installed after the condensation section of the steam pipe 10, and the second condensate return pipe 52 is installed at the bottom outside the steam chamber 32. Both the first condensate return pipe 36 and the second condensate return pipe 52 are connected to the water tank 3, and are used to discharge the water after the water vapor in the steam chamber 32 and the condensate in the steam pipe 10 into the water tank 3 to realize water recycling.

[0055] See also Figures 7 to 8As shown, in one embodiment of the present invention, the solar heat exchange device further includes an air inlet duct 6, which is connected to the first heating chamber 4. The air inlet duct 6 has two air inlets, each equipped with a first induced draft fan 7 and a second induced draft fan 9. The first induced draft fan 7 and the second induced draft fan 9 are used to draw cold air from nature into the air inlet duct 6. The second induced draft fan 9 is powered by a vane pump 11, and the two are connected by a transmission belt. The first induced draft fan 7 is powered by a solar panel and is used to assist in drafting air when the power of the second induced draft fan 9 is insufficient.

[0056] In this embodiment, the large pulley shaft 50 is connected to the shaft of the vane pump 11, the small pulley shaft 46 is connected to the worm gear 43, the large pulley 47 and the small pulley 48 transmit power through the conveyor belt 49, the second induced draft fan shaft 42 is connected to the shaft of the turbine 44, and the turbine 44 is connected to the worm gear 43, thereby converting the rotation of the small pulley 48 into the rotation of the fan in the second induced draft fan 9, and thus realizing the conversion of the power of the vane pump 11 into the power of the second induced draft fan 9.

[0057] See also Figures 1 to 2 As shown, in one embodiment of the present invention, the solar heat exchange device further includes a second heating chamber 16, in which a shell-and-tube heat exchanger 21 is installed. The shell-and-tube heat exchanger 21 is designed with fins 23 inside, which are used to fully heat the hot air entering the second heating chamber 16. The top of the shell-and-tube heat exchanger 21 is made of glass 22, which can heat the space inside the shell-and-tube heat exchanger 21 by absorbing sunlight, and can also reduce heat loss, forming a greenhouse environment. In addition, an arc-shaped corner is adopted at the corner of the shell-and-tube heat exchanger 21, which can effectively reduce the pressure drop of the wind.

[0058] In one embodiment of the present invention, the solar heat exchange device further includes a duct 13, which is connected to the first heating chamber 4 and the second heating chamber 16, and is used to send the pre-heated hot air in the first heating chamber 4 into the second heating chamber 16 for further heating; a temperature sensor and a wind speed sensor are also installed in the duct 13, which are used to detect the temperature and wind speed of the hot air flowing out of the first heating chamber 4, respectively.

[0059] See also Figure 9As shown, in one embodiment of the present invention, the solar heat exchange device further includes a reflector 15 and an array of convex lenses 14. The array of convex lenses 14 is located on top of the reflector 15, and a frame is provided around the array of convex lenses 14. The array of convex lenses 14 and the frame are fixed together by a second fixed pivot 41. The frame and the reflector 15 are fixed together by a first fixed pivot 40. The first fixed pivot 40 and the second fixed pivot 41 are located in two directions, giving the array of convex lenses 14 two degrees of freedom. Therefore, by adjusting the angle of the array of convex lenses 14, sunlight can be focused onto the glass 22 on top of the shell-and-tube heat exchanger 21. The inner side of the reflector 15 is a plane mirror 39, which is used to reflect sunlight shining on the plane mirror 39 onto the glass 22 on top of the shell-and-tube heat exchanger 21.

[0060] See also Figure 10 As shown, in one embodiment of the present invention, the solar heat exchange device further includes an air outlet duct 19, which is connected to the outlet of the second heating chamber 16. The air outlet duct 19 is used to send hot air into the heat exchange device to dry the crops.

[0061] In this embodiment, an air distribution valve is installed inside the air outlet duct 19 to regulate the temperature inside the air outlet duct 19. The second heating chamber 16 is connected to the air outlet duct 19, and the air outlet duct 19 is connected to the air distribution duct 18. An air distribution fan 17 is installed on the side of the air distribution duct 18 away from the air outlet duct 19. The air distribution fan 17 is used to send cold air from nature into the air distribution duct 18. The inner side of the air distribution duct 18 is equipped with a downwardly inclined baffle 37. This design allows the air to flow in one direction, so that cold air flows into the air outlet duct 19 along the air distribution duct 18, preventing hot air in the air outlet duct 19 from flowing out of the air distribution duct 18.

[0062] See also Figure 1 As shown, in one embodiment of the present invention, the solar heat exchange device further includes a frame 1, which is installed at the bottom of the solar collector 2. The frame 1 is used to place the entire solar heat exchange device and to position the solar heat exchange device at a certain height, thereby improving the efficiency of the solar heat exchange device in receiving solar energy.

[0063] The working process of the solar heat exchange device is as follows: The solar collector 2 converts solar energy into heat energy, raising the temperature of the copper plate 20 in the water tank 3 and the shell-and-tube heat exchanger 21. The copper plate 20 heats the water in the water tank 3. After the water in the water tank 3 boils, it generates high-temperature steam. The high-temperature steam flows through the shell-and-tube heat exchanger 30, raising its temperature. Then, the steam enters the steam chamber 32. The pressure valve 34 in the steam pipe 10 at the top of the steam chamber 32 creates high pressure for the steam. The vane pump 11 in the steam pipe 10 converts the kinetic energy of the high-pressure steam into mechanical energy to power the second induced draft fan 9. The kinetic energy of the vane pump 11 is converted into the kinetic energy of the second induced draft fan 9 through the transmission belt and worm gear device. Yes, the condenser 8 outside the steam pipe 10 can exchange heat between the high-temperature steam and the cold water in the condenser 8, thereby condensing the steam into condensate. The warm water and condensate after heat exchange enter the water tank 3 through the return pipe for further heating, realizing heat and water recycling. The exhaust fan in the air inlet pipe 6 draws cold air from nature into the first heating chamber 4 for heat exchange with the tubular heat exchanger 30. The hot air after the first heating enters the second heating chamber 16 through the air duct 13, where the shell-and-tube heat exchanger 21 reheats the hot air, further increasing its temperature. After the temperature is adjusted by the air distribution valve to reach the required temperature for drying crops, the air is discharged into the heat exchanger through the air outlet pipe 19 to dry the crops. The array of convex lenses 14 above the shell-and-tube heat exchanger 21 can concentrate sunlight onto the glass 22 on top of the shell-and-tube heat exchanger 21, thereby making full use of solar energy.

[0064] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects: The solar collector 2 converts solar energy into thermal energy through heating with copper plates 20 and heat exchange with shell-and-tube heat exchangers 21, and dries crops through processes such as steam treatment, condensation and condensation circulation, and hot air drying. The solar collector 2 uses solar energy to heat water to boiling to generate high-temperature steam. The high-temperature steam flows through the shell-and-tube heat exchanger 30, raising its temperature. The vane pump 11 in the steam pipe 10 converts the kinetic energy of the high-pressure steam into mechanical energy to drive the induced draft fan. The condensation device 8 is used to exchange heat between the high-temperature steam and cold water, causing the steam to condense into condensate. The condensate re-enters the water tank 3 through the return pipe for reheating, realizing heat circulation and water recycling. The air inlet device increases the hot air temperature through secondary heating in the first heating chamber 4 and the second heating chamber 16 to reach the temperature required for drying crops. The array of convex lenses 14 above the shell-and-tube heat exchanger 21 concentrates sunlight, further utilizing solar energy and reducing environmental pollution.

[0065] Example 2

[0066] like Figure 16As shown, this embodiment provides a solar heat exchange method based on the solar heat exchange device in Embodiment 1. The method includes:

[0067] S1: Controls the solar collector to heat the water in the tank to generate high-temperature steam.

[0068] S2: The high-temperature water vapor flows through the tubular heat exchanger to raise the temperature of the tubular heat exchanger. The tubular heat exchanger heats the air in the first heating chamber once to obtain air after one heating.

[0069] S3: The array of convex lenses focuses sunlight onto the glass above the shell-and-tube heat exchanger to heat the shell-and-tube heat exchanger. The shell-and-tube heat exchanger then heats the air after the first heating to obtain the second-heated air.

[0070] S4: The air after secondary heating is discharged into the heat exchange device through the air outlet pipe to dry the crops.

[0071] The solar collector is made of copper, which has high thermal conductivity, enabling it to convert absorbed sunlight into heat energy. This heat is rapidly transferred throughout the entire solar collector, raising the temperature of the copper plates and the shell-and-tube heat exchanger. The increased temperature of the copper plates heats the water in the tank, generating high-temperature steam. This steam then flows through the copper tubes of the heat exchanger, further warming the tubes. An array of convex lenses above the second heating chamber focuses sunlight, heating the upper part of the shell-and-tube heat exchanger through the glass above it. Cold air in nature experiences a temperature increase after passing through the first and second heating chambers.

[0072] See also Figures 11 to 13 As shown, Figures 11 to 13 This paper presents a heat transfer simulation of a solar heat exchange device using the k-ε model in ANSYS CFX software.

[0073] The mass balance equation can be obtained from the following formula:

[0074]

[0075] The dynamic equilibrium equations are obtained using the following formula:

[0076]

[0077] The energy conservation equation can be obtained from the following formula:

[0078]

[0079] Where x iThe coordinates are i = 1, 2, 3, representing the X, Y, and Z coordinate directions respectively; u i For x i The average velocity in the direction, m / s. ρ is the density of air, kg / m³. 3 ;where x j The coordinates are j = 1, 2, 3, representing the X, Y, and Z coordinate directions respectively; u j For x j Average velocity in the direction, m / s; P is fluid pressure, Pa; τ ij ρg is the stress vector. i Let F be the volume force in the i-th direction, in N; i For the source term. h is the specific enthalpy of hot air, J; η is the thermal conductivity of air; T is the temperature, K; S h For internal heat source items; J represents the work done by the surface force; φ represents the dissipation term.

[0080] See also Figures 14 to 15 As shown, Figure 15 The graph shows the temperature changes at various points under different speed conditions. It can be seen that the temperature rises rapidly from point 1 to point 2 and from point 3 to point 5. This is because these two sections are located in the first and second heating chambers respectively, and the tubular heat exchanger in the first heating chamber and the shell-and-tube heat exchanger in the second heating chamber can raise the air temperature. The temperature change is not significant from point 2 to point 3 because this section is located inside the air duct, where there is no heat source to heat the air. The temperature decreases from point 5 to point 6 because the air distribution valve in the outlet duct lowers the air temperature to reach the temperature required for drying crops. Figure 15 It can also be seen that the lower the wind speed, the higher the wind temperature. This is because a slower wind speed allows the natural wind to fully exchange heat with the heat exchangers in the first and second heating chambers.

[0081] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0082] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0083] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A solar heat exchange device, characterized in that, include: A solar collector (2) is connected to a water tank (3) and a shell-and-tube heat exchanger (21). The solar collector (2) can convert the collected solar energy into heat energy to heat the water in the water tank (3) and the shell-and-tube heat exchanger (21). The solar collector (2) has copper plates (20) of varying heights in the water tank (3) to improve the heating rate of the water in the water tank (3). Copper is used as the main component of the solar collector (2). The solar collector (2) is located at the bottom of the water tank (3), and the upper wall (26) of the water tank is provided with multiple vent holes, which are used to discharge water vapor from the water tank (3); The solar heat exchange device also includes a tubular heat exchanger (30), which is made of copper tubing. The tubular heat exchanger (30) is located in the first heating chamber (4), which is connected to the air inlet pipe (6) and the air duct (13). The bottom of the tubular heat exchanger (30) is connected to the round hole of the upper wall (26) of the water tank, and the upper end of the tubular heat exchanger (30) is connected to the steam chamber (32). The water vapor generated in the water tank (3) enters the steam chamber (32) through the tubular heat exchanger (30) to raise the temperature of the tubular heat exchanger (30) and heat the natural air in the first heating chamber (4) once. The air duct (13) is also connected to the second heating chamber (16), and a shell-and-tube heat exchanger (21) is provided in the second heating chamber (16). The shell-and-tube heat exchanger (21) is provided with fins (23) inside, and the fins (23) are used to fully heat the hot air that has passed through the first heating chamber (4). Above the second heating chamber (16) is a reflector (15), and the top of the reflector (15) is equipped with an array of convex lenses (14). The array of convex lenses (14) has two degrees of freedom, and the inner side of the reflector (15) is a plane mirror (39). The angle of the array of convex lenses (14) is adjusted so that sunlight is focused onto the glass (22) on the top of the shell-and-tube heat exchanger (21).

2. The solar heat exchanger according to claim 1, characterized in that, The side wall of the water tank (3) is provided with a water tank inlet (25), a water tank outlet (24) and a condensate return outlet (27). The water in the water tank (3) is used to reduce the temperature of the solar collector (2).

3. The solar heat exchanger according to claim 1, characterized in that, The solar heat exchange device also includes a steam chamber (32). The bottom of the steam chamber (32) is provided with a plurality of circular holes that communicate with the tubular heat exchanger (30). The circular holes are used to discharge the water vapor generated in the water tank (3) into the steam chamber (32). The top of the steam chamber (32) is connected to a safety pipe (12). A safety valve (35) is installed in the safety pipe (12). The safety valve (35) is in a closed state under normal conditions. When the pressure in the steam chamber (32) exceeds the set value of the safety valve (35), the safety valve (35) will open and discharge the water vapor in the steam chamber (32) through the safety pipe (12).

4. The solar heat exchanger according to claim 3, characterized in that, The top of the steam chamber (32) is also connected to a steam pipe (10), which is used to discharge the water vapor in the steam chamber (32) after energy recovery; the steam pipe (10) is equipped with a pressure valve (34), which is used to control the discharge speed of the water vapor in the steam pipe (10); the steam pipe (10) passes through a vane pump (11), which is powered by the high-pressure water vapor in the steam pipe (10).

5. The solar heat exchanger according to claim 4, characterized in that, The steam pipe (10) is connected to a condenser (8) on the side away from the vane pump (11); the condenser (8) is provided with a condenser water inlet (53), which is used to inject cold water into the condenser (8); the high-temperature steam in the steam pipe (10) will exchange heat with the cold water in the condenser (8) when passing through the condensation section, and turn the high-temperature steam into condensate.

6. The solar heat exchanger according to claim 5, characterized in that, The steam pipe (10) is equipped with a first condensate return pipe (36) after the condensation section, and a second condensate return pipe (52) is installed at the bottom of the outer side of the steam chamber (32). Both the first condensate return pipe (36) and the second condensate return pipe (52) are connected to the water tank (3).

7. The solar heat exchanger according to claim 4, characterized in that, The first heating chamber (4) is also connected to the air inlet duct (6). The air inlet duct (6) has two air inlets, which are equipped with a first induced draft fan (7) and a second induced draft fan (9). The induced draft fan is used to draw cold air from nature into the air inlet duct (6). The second induced draft fan (9) is connected to a vane pump (11), and the two are connected by a transmission belt to transmit power. The first induced draft fan (7) is powered by a solar panel and is used to assist in induced draft when the power of the second induced draft fan (9) is insufficient.

8. The solar heat exchanger according to claim 1, characterized in that, It also includes an air outlet duct (19) and a gas distribution duct (18). The second heating chamber (16) is connected to the air outlet duct (19), and the air outlet duct (19) is connected to the gas distribution duct (18). A gas distribution valve is installed in the air outlet duct (19) to regulate the temperature inside the air outlet duct (19). A gas distribution fan (17) is installed on the side of the gas distribution duct (18) away from the air outlet duct (19), and a downwardly inclined baffle (37) is installed on the inner side of the gas distribution duct (18).

9. The solar heat exchanger according to claim 1, characterized in that, The solar collector (2) is connected to a frame (1) at the bottom, and the frame (1) is used to adjust the height of the solar heat exchange device.

10. A solar heat exchange method, characterized in that, Based on the solar heat exchange device according to any one of claims 1-9, the method includes: The solar collector (2) is controlled to heat the water in the water tank (3) to generate high-temperature water vapor; The high-temperature steam flows through the tubular heat exchanger (30) to raise the temperature of the tubular heat exchanger (30). The tubular heat exchanger (30) heats the air in the first heating chamber (4) once to obtain air after one heating. An array of convex lenses (14) focuses sunlight onto the glass (22) above the shell-and-tube heat exchanger (21) to heat the shell-and-tube heat exchanger (21), which in turn heats the air after the first heating to obtain air after secondary heating. The air after secondary heating is discharged into the heat exchange device through the air outlet pipe (19) to dry the crops.

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