A solar water heater with outlet temperature control

Abstract

The application provides a solar water heater with water temperature control, which comprises a heat collecting pipe and a water tank, the heat collecting pipe comprises an evaporation end and a condensation end, the evaporation end absorbs solar heat, and the condensation end is inserted into the water tank to release heat to water in the water tank; characterized in that the water tank is divided into N heating independent areas, wherein N is greater than or equal to 2, the heat exchange area of the condensation end of each area is different, the heat exchange area of the condensation end of the N areas gradually increases, each area has an independent water inlet and a water outlet, the water outlet is connected to a water user, a water outlet valve is arranged on the water outlet, a temperature sensor is arranged in each area to detect the water temperature after heating, the temperature sensor and the water outlet valve are connected to a controller, a user inputs a water temperature, and the controller determines the opening degree of each water outlet valve according to the temperature detected by the temperature sensor to realize the water temperature input by the user. The application provides a solar water heater with fast temperature control, which can quickly output water with different temperatures and quickly meet the needs of users.

Description

Technical Field

[0001] This invention relates to a solar water heater, and more particularly to a solar water heater with outlet water temperature control. Background Technology

[0002] With the rapid development of modern society and economy, human demand for energy is increasing. However, the reserves of traditional energy sources such as coal, oil, and natural gas are constantly decreasing and becoming increasingly scarce, leading to continuous price increases. At the same time, the environmental pollution caused by conventional fossil fuels is becoming increasingly serious, all of which greatly restrict social development and the improvement of human quality of life. Energy issues have become one of the most prominent problems in the contemporary world. Therefore, the search for new energy sources, especially pollution-free clean energy, has become a hot research topic.

[0003] Solar energy is a clean, inexhaustible energy source with enormous reserves; the total amount of solar radiation received by the Earth's surface each year is 1 × 10⁻⁶. 18 The solar energy density is kW·h, which is more than ten thousand times the world's total annual energy consumption. However, due to the low energy density of solar radiation reaching the Earth (approximately one kilowatt per square meter) and its discontinuous nature, large-scale development and utilization face certain difficulties. Therefore, in order to widely utilize solar energy, not only are technical problems to be solved, but it must also be economically competitive with conventional energy sources.

[0004] The output of temperature control for solar water heaters has always been a research hotspot in the solar energy field. Various studies have been conducted in existing technologies. CN103216945A provides a solar water heater with temperature control function. The water heater includes a central controller, a water heater, and a water tank connected to the water heater. The water inlet of the water heater is connected to an external water source via a pipe. The water tank is connected to the water heater, and both the water tank and the water heater are equipped with electric heating devices and temperature control devices, enabling temperature control of the water heater. This invention can control the heating power according to the water temperature, avoiding rapid thermal expansion of the inner tank, and simultaneously control the water temperature according to the water flow rate, ensuring uniform heating temperature. CN106016788A discloses a temperature control system and its control method. This temperature control system includes a storage tank for storing heated phase change material, at least one stirrer disposed inside the storage tank, and at least one hollow pipe disposed inside the storage tank. The air inlets of the hollow pipes are connected to hot and cold air blowers. Temperature sensors are disposed on the side walls of both the storage tank and the hollow pipes. This invention can monitor the temperature of the phase change material (PCM) inside the storage tank at any time, and obtain the temperature inside the tank in real time through a temperature sensor. It controls hot or cold air blowers to blow hot or cold air into the hollow pipes to heat or cool the PCM in the tank, achieving precise temperature control. The agitator ensures the flow of PCM throughout the tank, guaranteeing temperature uniformity. This results in good heat distribution, simple operation, precise and rapid temperature control, safety, and intelligent control of molten salt storage tanks. CN110806021A provides a temperature-controlled trough-type solar thermal collector system, including a water heater. The water heater includes collector tubes and reflectors. The collector tubes absorb solar energy and heat the water inside. Multiple collector tubes are connected in parallel, with a reflector corresponding to the lower part of each tube. The system is characterized by a temperature sensor at the outlet of each collector tube to measure the fluid temperature at the outlet. The control system is connected to the temperature sensor data and determines the heating status of each collector tube based on the data detected by the temperature sensor. This invention, through the aforementioned control system, can identify collector tubes with low outlet temperatures, allowing for inspection and identification of the cause of the problem, facilitating improvements. The control system can also automatically alert you when a collector tube's outlet temperature is below the normal value.

[0005] Existing temperature control technologies have complex structures and are relatively slow to implement. Therefore, this application proposes an improved, novel structure for intelligent control of output temperature in a solar water heater, enabling it to quickly output water at different temperatures and rapidly meet user needs. Summary of the Invention

[0006] In order to overcome the defects and shortcomings of the existing technology, the present invention provides a novel solar water heater that can quickly output water at different temperatures to meet the user's needs.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows:

[0008] A solar water heater with outlet water temperature control includes a collector tube and a water tank. The collector tube includes an evaporation end and a condensation end. The evaporation end absorbs solar heat, and the condensation end is inserted into the water tank to release heat to the water in the tank. The water tank is characterized by being divided into N independently heated zones, where N is greater than or equal to 2. The heat exchange area of ​​the condensation end in each zone is different, with the heat exchange area of ​​the condensation end gradually increasing across the N zones. Each zone has an independent inlet and outlet. The outlet is connected to the user and equipped with an outlet valve. A temperature sensor is installed in each zone to detect the temperature of the heated water within that zone. The temperature sensor, outlet valve, and controller are connected for data transmission. The user inputs the desired water temperature, and the controller determines the opening degree of each outlet valve based on the temperature detected by the temperature sensor, thereby achieving the user-input water temperature.

[0009] As an improvement, the controller stores and sorts the temperature data detected by the temperature sensor. After receiving the user's input water temperature, the controller compares the water temperature with the temperature data in the database. If the temperature data matches, the controller controls the corresponding area's outlet valve to open fully and the outlet valves of other areas to close. If the temperature data does not match, the controller selects two adjacent temperature data, so that the water temperature is between the two temperature data. The controller then adjusts the opening of the outlet valves corresponding to the two data, and closes the other outlet valves, thus achieving rapid output of water that meets the requirements.

[0010] As an improvement, the water tank is provided with at least one partition along the vertical direction, thereby setting the water tank into multiple heating zones distributed from left to right.

[0011] As an improvement, the heat exchange area of ​​the condenser end in different heating zones gradually increases from left to right.

[0012] As an improvement, the water tank is provided with at least one partition along the lateral direction, thereby setting the water tank into multiple heating zones distributed vertically.

[0013] As an improvement, the heat exchange area of ​​the condenser end of different heating zones in the water tank gradually increases from top to bottom.

[0014] As an improvement, N=2, which divides the heating area into an upper region and a lower region.

[0015] As an improvement, a cold water tank is included, with the inlet connected to it. The cold water tank has a separate cold water outlet with a cold water valve. A temperature sensor is installed inside the cold water tank to detect the cold water temperature. The temperature sensor and the cold water valve are connected to the controller for data transmission. The controller stores and sorts the temperature data detected by the sensor. When the controller receives the user's input water temperature, it compares the water temperature with the temperature data in the database. If the temperature data matches, the controller fully opens the outlet valve of the corresponding area and closes the outlet valve and cold water valve of the other area. If the temperature data does not match, the controller selects two adjacent temperature values ​​between the cold water temperature and two hot water temperatures, allowing the water temperature to be between the two temperature values. The controller then adjusts the opening of the valve corresponding to the two values, closing the other valve, thus achieving rapid output of water that meets the requirements.

[0016] As an improvement, the baffle is a heat conductor, and the water flows in opposite directions in the upper and lower regions.

[0017] As an improvement, the heat collection tube is a pulsating heat tube.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] This invention sets up multiple independent heating zones, each of which can output hot water at different temperatures. This allows the user's desired temperature to be quickly and accurately located between two data points, and the desired temperature can be quickly output by adjusting the valve corresponding to the data point. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the water tank structure of the solar water heater of the present invention;

[0021] Figure 2 This is another schematic diagram of the water tank structure of the solar water heater of the present invention;

[0022] Figure 3 yes Figure 1 Schematic diagram of the control structure;

[0023] Figure 4 This is a schematic diagram of the control structure for two regions;

[0024] Figure 5 This is a schematic diagram of the water tank structure of the integrated heat collection tube water heater of the present invention. Detailed Implementation

[0025] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0026] Figure 1-5The solar water heater of the present invention is shown. A solar water heater with outlet water temperature control includes a heat collection tube 1 and a water tank 2. The heat collection tube includes an evaporation end 11 and a condensation end 12. The evaporation end absorbs solar heat, and the condensation end is inserted into the water tank 2 to release heat to the water in the water tank 2.

[0027] like Figure 1 As shown, the water tank 2 is divided into N independently heated zones 21, where N is greater than or equal to 2. The heat exchange area of ​​the condenser end of each zone is different or the amount of cold water exchanged is different, so that the water in different zones has different temperatures after heating. Each zone has an independent inlet 22 and outlet 23. The outlet 23 is connected to the user and a water outlet valve 3 is installed on the outlet. A temperature sensor is installed in each zone to detect the water temperature after heating in the zone. The temperature sensor, the outlet valve, and the controller are connected to the controller. The user inputs the water temperature, and the controller determines the opening degree of each outlet valve 3 based on the temperature detected by the temperature sensor to realize the water temperature input by the user.

[0028] This invention sets up multiple independent heating zones, each of which can output hot water at different temperatures. This allows the user's desired temperature to be quickly and accurately located between two data points, and the desired temperature can be quickly output by adjusting the valve corresponding to the data point.

[0029] As an improvement, the controller stores and sorts temperature data detected by the temperature sensor. Upon receiving the user's input water temperature, the controller compares it with the temperature data in the database. If the temperature data matches, the controller fully opens the corresponding water outlet valve and closes the valves in other areas. If the temperature data does not match, the controller selects two adjacent temperature data points, placing the water temperature between them. The controller then adjusts the opening of the valves corresponding to these two data points, closing the other valves, thus achieving rapid output of water at the desired temperature. This invention allows direct access to hot water from the area closest to the desired output temperature, enabling rapid output of the user's required temperature.

[0030] As an improvement, such as Figure 1 , 3 As shown, the water tank is provided with at least one partition 4 along the vertical direction, thereby setting the water tank into multiple heating zones distributed from left to right.

[0031] As an improvement, the hot water temperature in different heating zones gradually increases or decreases from left to right. This gradual increase or decrease in the output hot water temperature simplifies data sorting within the controller, making it easier to control the opening and closing of corresponding valves—only adjacent valves are opened and closed, facilitating data processing.

[0032] As an improvement, the temperature can be gradually changed by gradually increasing or decreasing the heat exchange area at the condenser end, or by gradually increasing or decreasing the amount of water heated in the area.

[0033] As an improvement, such as Figure 2 , 4 As shown, the water tank is provided with at least one partition 4 along its horizontal direction, thereby setting the water tank into multiple heating zones distributed vertically. As an improvement, the hot water temperature in different heating zones gradually increases or decreases from top to bottom. By gradually increasing or decreasing the output hot water temperature, the data sorting within the controller is simplified, making it easier to control the opening and closing of corresponding valves, as only adjacent valves are opened and closed, and data processing is convenient.

[0034] As an improvement, the temperature can be gradually changed by gradually increasing or decreasing the heat exchange area at the condenser end, or by gradually increasing or decreasing the amount of water heated in the area.

[0035] As an improvement, partition 4 is a heat conductor, and the water flows in opposite directions in adjacent areas. Through the heat conductor, heat transfer between adjacent areas can be achieved, and the opposite flow direction of the adjacent water enables counter-current heat exchange similar to that of a shell-and-tube heat exchanger, thereby more fully absorbing solar heat and improving the heat transfer effect.

[0036] This invention discloses a method for rapidly controlling the outlet water temperature, comprising the following steps:

[0037] 1) Temperature sensors detect the temperature of hot water in each area and transmit the hot water temperature data and the corresponding valve code to the controller;

[0038] 2) The controller stores the temperature data detected by the temperature sensor and the valve code into the database, and sorts the temperature data and valve code according to the temperature value;

[0039] 3) The user inputs the water temperature. After receiving the user's input water temperature, the controller compares the water temperature with the temperature data in the database. If the temperature data matches, the controller controls the outlet valve corresponding to the temperature data to open fully and the other outlet valves to close. If the temperature data does not match, proceed to step 4).

[0040] 4) The controller selects two adjacent temperature data from the database based on the water temperature, so that the water temperature is between the two temperature data. The controller then adjusts the valve opening corresponding to the two data, while other outlet valves are closed, so as to quickly output water that meets the requirements.

[0041] As an improvement, in step 4, if the user's water temperature is T, the adjacent high-temperature data in the database is T1, and the low-temperature data is T2, then the valve opening corresponding to the high-temperature data and the valve opening corresponding to the low-temperature data is (T-T2) / (T1-T). This allows for the rapid output of water that meets the requirements.

[0042] As an improvement, in step 4, if the required temperature increases, the opening degree of the high-temperature valve is increased and the opening degree of the low-temperature valve is decreased.

[0043] As an improvement, in step 4, if the required temperature decreases, the opening degree of the high-temperature valve is reduced and the opening degree of the low-temperature valve is increased.

[0044] As an improvement, if the water usage requirements are still not met even when the high-temperature valve or the low-temperature valve is 100% open or 0% open, then return to step 3).

[0045] As an improvement, such as Figure 2 , 4 As shown, N=2, which divides the heating area into an upper region and a lower region.

[0046] As an improvement, it includes a cold water tank 5, with an inlet connected to the cold water tank, a separate cold water output pipe 7 connected to the user, a cold water valve 6 installed on the cold water output pipe, a temperature sensor installed inside the cold water tank to detect the temperature of the cold water, and the temperature sensor and the cold water valve connected to the controller for data transmission. The controller is used to store the temperature data detected by the temperature sensor and the corresponding cold water valve code.

[0047] As an improvement, the database in step 2) stores data including cold water tank temperature data and cold water valve coding data. This setting allows cold water to participate in the temperature output, displaying temperatures between the cold water and the lowest possible temperature. This increases the range of the temperature output.

[0048] As an improvement, such as Figure 4As shown, the system includes a cold water tank 5, an inlet connected to the cold water tank, a separate cold water output pipe 7 connected to the user, a cold water valve 6 on the cold water output pipe, and a temperature sensor inside the cold water tank to detect the temperature of the cold water. The temperature sensor and the cold water valve are connected to the controller for data transmission. The controller stores and sorts the temperature data detected by the temperature sensor. After receiving the user's input water temperature, the controller compares the water temperature with the temperature data in the database. If the temperature data matches, the controller controls the corresponding area's outlet valve to open fully, while the outlet valve and cold water valve of the other area are closed. If the temperature data does not match, the controller selects two adjacent temperature data between the cold water temperature and two hot water temperatures, allowing the water temperature to be between the two temperature data. The controller then adjusts the opening of the valves corresponding to the two data points, closing the other valve, thus achieving rapid output of water that meets the requirements.

[0049] As an improvement, the partition acts as a heat conductor, and the water flows in opposite directions in the upper and lower regions. The heat conductor enables heat transfer between adjacent regions, and the opposite flow directions achieve counter-current heat exchange similar to a shell-and-tube heat exchanger, thus maximizing the absorption of solar heat and improving heat transfer efficiency.

[0050] As an improvement, the heat collection tube is a pulsating heat tube. For example... Figure 5 As shown. Pulsating heat pipes have the advantages of simple structure, small size, light weight, easy manufacturing, low cost, and excellent performance. The operating principle and heat transfer characteristics of pulsating heat pipes are very different from those of traditional heat pipes. When a pulsating heat pipe is working, it can generally be divided into three parts: the two ends of the pipe are the heating section and the cooling section, respectively, and the middle section is the adiabatic section, which can also be omitted. The operating principle of a pulsating heat pipe is as follows: when the pipe diameter is small enough, a series of vapor plugs and liquid plugs will form inside the pipe; in the heating section, the liquid film between the vapor bubbles or vapor column and the pipe wall will be continuously heated and evaporated, causing the vapor bubbles to expand and the pressure to rise; at the same time, in the cooling section, the vapor bubbles will condense, shrink, and rupture, causing the pressure to drop, resulting in a driving pressure difference between the heating section and the cooling section, which pushes the vapor and liquid plugs to reciprocate between the heating section and the cooling section, and heat is transferred from one end to the other, thereby realizing heat transfer or temperature control. It is evident that in a pulsating heat pipe, the phase change of the working fluid mainly provides power for the working fluid. The heat transfer due to phase change accounts for a relatively small proportion of the total heat transfer in the pulsating heat pipe. The heat pipe mainly relies on the sensible heat change of the working fluid to achieve heat transfer.

[0051] As an improvement, such as Figure 5As shown, the pulsating heat pipe includes multiple parallel straight pipes 13. Adjacent straight pipes are connected by an upper bend 14 and a lower bend 15. The leftmost and rightmost straight pipes 13 are connected by a horizontal straight pipe 16. The straight pipes 13, bends 14 and 15, and horizontal straight pipe 16 form a series loop structure. The horizontal straight pipe 16 is located above the upper bend 14 and has a gap between it and the upper bend 14. The condensing end 12 includes the upper part of the straight pipe 13, the upper bend 14, and the horizontal straight pipe 16. The water tank 2 is divided into an upper region and a lower region by a partition 4. The upper region and the lower region have an inlet 22 and an outlet 23, respectively.

[0052] As an improvement, the upper region includes the horizontal straight pipe, the upper part of the leftmost straight pipe, and the upper part of the rightmost straight pipe, while the lower region includes the upper curved pipe and the upper part of the straight pipe. The heat exchange area of ​​the upper region is smaller than that of the lower region, therefore the output water temperature of the upper region is generally lower than that of the lower region.

[0053] The baffle acts as a heat conductor, allowing heat exchange between the fluids in the upper and lower regions. By installing zoned heat-conducting baffles, heat exchange between the fluids in the upper and lower regions can be achieved, resulting in heat complementarity between the two regions. This allows the higher-temperature fluid in one region to transfer heat to the lower-temperature fluid in the other, and then the higher-temperature fluid, after cooling down, absorbs heat from the heat pipe, thus maximizing heat exchange. Through the complementary heat conduction of the baffles, optimal heat exchange performance can be achieved regardless of whether the flow is co-current or counter-current.

[0054] As an improvement, the baffle includes a horizontal section 41 located in the gap, an extension section 42 extending downward from both ends of the horizontal section, and a connecting section 43 connecting the extension section to the left and right walls of the water tank. A baffle is provided in the lower region, and the baffle includes an upper baffle 7 and a lower baffle 8 arranged at intervals. The upper baffle extends downward from the horizontal section, and the lower baffle extends upward from the lower wall of the water tank. The straight pipe is arranged between adjacent baffles, and the upper curved pipe is arranged in the gap between the lower baffle and the baffle.

[0055] This invention sets up two regions, with the lower region equipped with a baffle structure, so that the straight pipe sections at different positions of the condensation end of the pulsating heat pipe can be adapted to the shape of the region, allowing the heat exchange fluid to fully contact the straight pipe sections and improving the heat exchange effect.

[0056] As an improvement, the water flow direction in the upper region is opposite to the flow direction of the fluid in the straight pipe, and the water flow direction in the lower region is opposite to the flow direction of the fluid in the bend. This allows the fluid to flow in the opposite direction to the fluid flow path within the heat pipe, thereby maximizing heat exchange. By implementing zoned flow, true counter-current flow can be achieved.

[0057] As an improvement, along the water flow direction in the lower region, the downward extension length of the upper baffle and the upward extension length of the lower baffle gradually increase, reaching the middle position of the flow channel in the lower region and then gradually decreasing. Because the connecting section is located at the outlet and inlet of the upper and lower regions, respectively, or the inlet and outlet of the upper and lower regions, the temperature difference between them is greatest, resulting in the best heat exchange effect. This is because the change in the extension length of the baffle increases the heat exchange area and turbulence effect at the middle position, thereby increasing the heat transfer coefficient and improving the overall heat exchange effect. This achieves overall heat exchange equilibrium, further realizing the optimal heat exchange effect.

[0058] As an improvement, along the water flow direction in the lower region, the downward extension length of the upper baffle and the upward extension length of the lower baffle gradually increase, reaching the middle of the flow channel in the lower region, and then gradually decrease while continuously increasing in magnitude. This arrangement further achieves overall heat exchange equilibrium and improves the heat exchange effect.

[0059] As an improvement, the baffle is a symmetrical structure along the middle of the lower wall of the water tank.

[0060] As an improvement, the thermal conductivity varies at different locations on the partition, with the horizontal section exhibiting higher thermal conductivity than the extended section, which in turn has higher thermal conductivity than the connecting section. This is because, when the inlets of the upper and lower regions are not located on the same side of the water tank, the first and third parallel sections are positioned as either the outlet and inlet of the upper and lower regions, or the inlet and outlet of the upper and lower regions, respectively. In this case, the temperature difference between the two is greatest, resulting in the best heat exchange effect. This is because increasing the thermal conductivity at the intermediate position enhances the heat exchange effect, achieving overall heat exchange balance and thus further optimizing the heat exchange performance.

[0061] While the present invention has been disclosed above with reference to preferred embodiments, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A solar water heater with outlet water temperature control, comprising a collector tube and a water tank, the collector tube comprising an evaporating end and a condensing end, the evaporating end absorbing solar heat, and the condensing end being inserted into the water tank to release heat to the water in the tank; characterized in that, The water tank is divided into N independently heated zones, where N is greater than or equal to 2. Each zone has a different heat exchange area at the condenser end or a different volume of cold water for heat exchange, resulting in different water temperatures after heating. Each zone has an independent inlet and outlet. The outlet connects to the user and is equipped with a valve. A temperature sensor is installed in each zone to detect the heated water temperature. The temperature sensors, outlet valves, and controller are connected. The user inputs the desired water temperature, and the controller determines the opening of each outlet valve based on the temperature detected by the temperature sensor. The controller stores and sorts the temperature data detected by the temperature sensors. After receiving the user's input water temperature, the controller compares it with the temperature data in the database. If the temperature data matches, the controller fully opens the outlet valve of the corresponding zone and closes the outlet valves of other zones. If the temperature data does not match, the controller selects two adjacent temperature values, placing the water temperature between them, and adjusts the opening of the outlet valves corresponding to these two values, closing the other outlet valves to quickly output the required water temperature.

2. The solar water heater as described in claim 1, characterized in that, The water tank is provided with at least one partition along the vertical direction, thereby setting the water tank into multiple heating zones distributed from left to right.

3. The solar water heater as described in claim 2, characterized in that, Along the left-to-right direction, the temperature of the hot water in different heating zones gradually increases or decreases.

4. The solar water heater as described in claim 3, characterized in that, The temperature can be gradually changed by gradually increasing or decreasing the heat exchange area at the condenser end, or by gradually increasing or decreasing the amount of water heated in the area.

5. The solar water heater as described in claim 1, characterized in that, The water tank is provided with at least one partition along the horizontal direction, thereby setting the water tank into multiple heating zones distributed vertically.

6. The solar water heater as described in claim 5, characterized in that, Along the top-to-bottom direction, the heat exchange area of ​​the condenser end of the water tank gradually increases in different heating zones.

7. The solar water heater as described in claim 6, characterized in that, N=2, which divides the heating area into an upper region and a lower region.

8. The solar water heater as described in claim 6, characterized in that, The partition is a heat conductor, and the water flows in opposite directions in the upper and lower regions.

9. The solar water heater as described in claim 6, characterized in that, The heat collection tube is a pulsating heat tube.

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