A hot water system maximizing utilization of solar energy and a control method thereof

Abstract

The application discloses a hot water system maximizing utilization of solar energy and a control method thereof. The system comprises a heat collecting water tank, a constant temperature water tank and a plurality of solar energy collectors. The heat collecting water tank is connected with a cold water source through a first water pipe and connected with the solar energy collectors through a second water pipe. A first water pump and a first valve assembly are arranged on the second water pipe. The solar energy collectors are connected with the heat collecting water tank and the constant temperature water tank through a third water pipe and a fourth water pipe respectively. Second valve assemblies are arranged on the third water pipe and the fourth water pipe respectively. The heat collecting water tank and the constant temperature water tank are connected with a fourth water pipe and a fifth water pipe. The constant temperature water tank is connected with a standby heating device through a sixth water pipe. In the working process, the system can maximize utilization of solar energy. The standby heating device is used more reasonably. The system can ensure quick adjustment response of water supply temperature and reduce energy consumption, and the energy-saving effect is remarkable.

Description

Technical Field

[0001] This invention relates to the field of solar-powered hot water systems, and more specifically to a hot water system that maximizes the utilization of solar energy and its control method. Background Technology

[0002] Traditional solar thermal collectors store water in a tank on top. The water in the tank is heated by solar energy during the day and is generally used for showering at night. After the water in the tank is used up, the tap water inlet valve is opened or a water pump is started to replenish the tank. In recent years, some businesses have begun to use solar water heating systems in areas with high hot water demand, such as employee dormitories, in order to save costs.

[0003] The control system is a core component of a centralized solar water heating system, directly impacting its operational stability and energy-saving performance. With the widespread adoption of rooftop solar water heating systems in public buildings across China, numerous rudimentary and low-end control systems have also proliferated, resulting in many projects failing to achieve their expected energy-saving goals. Specifically, solar water heating systems are affected by cloudy or rainy weather, necessitating the configuration of auxiliary heat sources and the management of the entire system through a control system during the design, construction, and operation phases. However, most current solar control systems offer rudimentary control over the heating method, failing to maximize the utilization of solar energy. Specifically, the control system improperly controls auxiliary heating equipment, failing to prioritize the use of solar energy, thus hindering its maximum utilization. Furthermore, when the water tank temperature falls below the set temperature, the auxiliary heat source immediately activates to maintain the set temperature, neglecting the utilization of solar energy and resulting in energy waste. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a hot water system that maximizes the utilization of solar energy and its control method.

[0005] To achieve the above objectives, in a first aspect, the present invention provides a hot water system that maximizes the utilization of solar energy, comprising a hot water collection tank, a constant temperature water tank, and a plurality of solar collectors. The hot water collection tank is connected to a cold water source via a first water pipe and to the solar collectors via a second water pipe. The second water pipe is equipped with a first water pump and a first valve assembly. The solar collectors are connected to the hot water collection tank and the constant temperature water tank via third and fourth water pipes, respectively. Second valve assemblies are connected to the third and fourth water pipes, respectively. A fourth and fifth water pipe connect the hot water collection tank and the constant temperature water tank. The fourth water pipe is connected to the second water pump and the third valve assembly. The constant temperature water tank is connected to the inlet of the backup heating device via a sixth water pipe. The sixth water pipe is equipped with a third water pump and a fourth valve assembly. The outlet of the backup heating device is connected to the constant temperature water tank via a seventh water pipe. The constant temperature water tank is connected to the hot water supply area via an eighth water pipe. The solar collector is connected to a first temperature sensor. The hot water collection tank is equipped with a second temperature sensor. The constant temperature water tank is equipped with a third temperature sensor. The first water pump, the second water pump, the second valve assembly, the first temperature sensor, the second temperature sensor, the third temperature sensor, and the backup heating device are all connected to the solar control cabinet. The third water pump is connected to the backup heating device.

[0006] Furthermore, the hot water tank is equipped with a first liquid level sensor, and the constant temperature water tank is equipped with a second liquid level sensor.

[0007] Furthermore, a fourth temperature sensor is installed on the second water pipe.

[0008] Furthermore, the backup heating device is a heat pump type backup heating device.

[0009] Furthermore, the cold water source is tap water, and a fifth valve assembly is provided on the first pipeline, which is connected to the solar control cabinet.

[0010] Furthermore, the eighth water pipe is equipped with a fourth water pump and a sixth valve assembly, and the fourth water pump is connected to the solar control cabinet.

[0011] In a second aspect, the present invention provides a control method for the above-mentioned hot water system that maximizes the utilization of solar energy, comprising:

[0012] (1) Low water level replenishment

[0013] When the water level in the hot water tank is lower than the set lower limit of the water level in the hot water tank, the solar control cabinet controls the fifth valve assembly to open; when the water level in the hot water tank reaches the water level in the hot water tank, it controls the fifth valve assembly to close.

[0014] When the water level in the constant temperature water tank is lower than the set lower limit, the solar control cabinet controls the fifth valve assembly to open, and cold water is added into the hot water collection tank. Then, it overflows into the constant temperature water tank through the fifth water pipe between the hot water collection tank and the constant temperature water tank. When the water level in the constant temperature water tank reaches the upper limit, the solar control cabinet controls the fifth valve assembly to close.

[0015] (2) Control of solar collectors

[0016] When the water temperature of the solar collector minus the water temperature of the hot water tank is greater than or equal to the first temperature difference threshold, the solar control cabinet controls the first water pump to start and the second valve assembly on the third water pipe to open. During this period, if the water level of the hot water tank is lower than the set lower limit, or the temperature of the hot water tank reaches the set upper limit, or the water temperature of the solar collector minus the water temperature of the hot water tank is less than or equal to the second temperature difference threshold, the solar control cabinet controls the first water pump to stop and the second valve assembly on the third water pipe to close.

[0017] (3) Circulation control between the hot water tank and the constant temperature water tank

[0018] When the water temperature in the constant temperature water tank is less than or equal to the set lower limit of the constant temperature water tank, and the water temperature in the hot water tank minus the water temperature in the constant temperature water tank is greater than or equal to the third temperature difference threshold, the solar control cabinet controls the second water pump to start. During this period, if the water temperature in the constant temperature water tank is greater than or equal to the set upper limit of the constant temperature water tank, the solar control cabinet controls the second water pump to stop.

[0019] (4) Control of standby heating device

[0020] Between 8:00 AM and 4:00 PM, if the water temperature in the constant temperature water tank is greater than or equal to the set first start-up temperature, the solar control cabinet will control the backup heating device to stop.

[0021] If the water temperature in the constant temperature water tank is less than the set first start temperature, first determine if the water temperature of the solar collector is greater than the set direct supply temperature. If the water temperature of the solar collector is greater than the set direct supply temperature, the solar control cabinet first controls the first water pump to start and the second valve assembly on the fourth water pipe to open, so that the hot water from the solar collector flows directly into the constant temperature water tank. When the water temperature in the constant temperature water tank is still lower than the set first start temperature within the set time, the solar control cabinet controls the backup heating device to start, and the backup heating device controls the third water pump to start, until the water temperature in the constant temperature water tank is greater than or equal to the set first start temperature. Then, the backup heating device controls the third water pump to stop, and the solar control cabinet controls the backup heating device to stop.

[0022] From 4 PM to 10 PM, if the water temperature in the constant temperature water tank is less than the set second start temperature, the solar control cabinet will control the backup heating device to run, and the backup heating device will control the third water pump to start. When the water temperature in the constant temperature water tank is greater than or equal to the set second start temperature, the solar control cabinet will control the backup heating device to stop, and the backup heating device will control the third water pump to stop.

[0023] Between 10 PM and 6 AM, if the water temperature in the hot water tank is less than the set second start-up temperature, the solar control cabinet will start the backup heating device and the second water pump, and the backup heating device will control the third water pump to run until the water temperature in the hot water tank is greater than or equal to the set second start-up temperature. Then, the solar control cabinet will stop the backup heating device and the second water pump, and the backup heating device will control the third water pump to stop.

[0024] Beneficial effects: The system of this invention integrates components such as a hot water tank, a constant temperature water tank, a solar collector, and a backup heating device. During operation, it can automatically control water replenishment based on the collected water level signal, and can activate the solar collector, backup heating device, and corresponding water pumps and valve assemblies based on the collected temperature signal. This maximizes the utilization of solar energy, and the timing of the backup heating device's activation is more reasonable. While ensuring rapid response to water supply temperature adjustments, it reduces system energy consumption, resulting in significant energy-saving effects. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of a hot water system that maximizes the utilization of solar energy according to an embodiment of the present invention. Detailed Implementation

[0026] The present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments. These embodiments are implemented based on the technical solutions of the present invention, and it should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0027] like Figure 1As shown, this embodiment of the invention provides a hot water system that maximizes the utilization of solar energy, including a hot water collection tank 1, a constant temperature water tank 2, and a plurality of solar collectors 3, which are preferably connected in parallel. The hot water collection tank 1 is connected to a cold water source through a first water pipe 4, and is also connected to the water tanks of the solar collectors 3 through a second water pipe 5. A first water pump 6 and a first valve assembly 7 are provided on the second water pipe 5. The solar collectors are connected to the hot water collection tank 1 and the constant temperature water tank 2 through a third water pipe 8 and a fourth water pipe 9, respectively. A second valve assembly 10 is connected to the third water pipe 8 and the fourth water pipe 9 respectively. A fourth water pipe 11 and a fifth water pipe 12 are connected between the hot water collection tank 1 and the constant temperature water tank 2. The fourth water pipe 11 is connected to the second water pump 13 and the third valve assembly 14. The constant temperature water tank 2 is connected to the inlet of the standby heating device 16 through the sixth water pipe 15. The sixth water pipe 15 is equipped with the third water pump 17 and the fourth valve assembly 18. The outlet of the standby heating device 16 is connected to the constant temperature water tank 2 through the seventh water pipe 19. The constant temperature water tank 2 is connected to the hot water supply area through the eighth water pipe 20. The solar collector 3 is connected to a first temperature sensor T1, which is used to measure the water temperature of the solar collector 3. A second temperature sensor T2 is installed on the hot water collection tank 1, which is used to measure the water temperature of the hot water collection tank 1. A third temperature sensor T3 is installed on the constant temperature water tank 2, which is used to measure the water temperature of the constant temperature water tank 2. The first water pump 6, the second water pump 13, the second valve assembly 10, the first temperature sensor T1, the second temperature sensor T2, the third temperature sensor T3, and the backup heating device 16 are all connected to the solar control cabinet 21. The third water pump 17 is connected to the backup heating device 16.

[0028] To facilitate automatic water replenishment control, a first liquid level sensor H1 is installed on the hot water tank 1, and a second liquid level sensor H2 is installed on the constant temperature water tank 2.

[0029] To prevent the water in the second water pipe 5 from freezing, a fourth temperature sensor T4 is installed on the second water pipe 5. When the water temperature in the second water pipe 5 is <4℃ (adjustable), the first water pump starts automatically; when the water temperature in the second water pipe 5 is ≥6℃ (adjustable), the first water pump stops automatically.

[0030] The backup heating device in this embodiment of the invention is preferably a heat pump type backup heating device.

[0031] The cold water source can be groundwater, which requires a corresponding water pump for extraction. Tap water is preferred, in which case a fifth valve assembly 22 needs to be installed on the first pipeline 4. The fifth valve assembly 22 is connected to the solar control cabinet 21, and its operation is controlled by the solar control cabinet 21.

[0032] The constant temperature water tank 2 can be set in a high position and rely on gravity to supply water. As a preferred embodiment, a fourth water pump 23 and a sixth valve assembly 24 are provided on the eighth water pipe 20. The fourth water pump 23 is connected to the solar control cabinet 21.

[0033] The aforementioned first valve assembly 7, third valve assembly 14, fourth valve assembly 18, and sixth valve assembly 24 each include two manually operated shut-off valves respectively located on the inlet and outlet sides of the corresponding water pumps. These manually operated shut-off valves are normally open during use and can be closed when maintenance of the corresponding components is required. A one-way shut-off valve is also provided between the manually operated shut-off valve on the outlet side and the corresponding water pump. The aforementioned second valve assembly 10 and fifth valve assembly 22 each include an electric valve controlled by a solar control cabinet. A manually operated shut-off valve is connected to each side of this electric valve, and both manually operated shut-off valves are connected to a backup shut-off valve on their respective sides. Preferably, the aforementioned first water pump 6, second water pump 13, third water pump 17, and fourth water pump 23, and the valves on both sides, are in two sets, serving as backups for each other. Furthermore, the aforementioned hot water tank 1, constant temperature water tank 2, and all pipelines are equipped with an insulation layer on their outer sides, providing good insulation performance.

[0034] Based on the above embodiments, those skilled in the art will readily understand that the present invention also provides a control method for a hot water system that maximizes the utilization of solar energy, including:

[0035] (1) Low water level replenishment

[0036] When the water level in the hot water tank is lower than the set lower limit of the water level in the hot water tank, the solar control cabinet controls the fifth valve assembly to open; when the water level in the hot water tank reaches the water level in the hot water tank, it controls the fifth valve assembly to close.

[0037] When the water level in the constant temperature water tank is lower than the set lower limit, the solar control cabinet controls the fifth valve assembly to open, and cold water is added into the hot water collection tank. Then, it overflows into the constant temperature water tank through the fifth water pipe between the hot water collection tank and the constant temperature water tank. When the water level in the constant temperature water tank reaches the upper limit, the solar control cabinet controls the fifth valve assembly to close.

[0038] (2) Control of solar collectors

[0039] When the water temperature of the solar collector is greater than or equal to the water temperature of the hot water tank, the solar control cabinet controls the first water pump to start and the second valve assembly on the third water pipe to open. During this period, if the water level of the hot water tank is lower than the set lower limit, or the temperature of the hot water tank reaches the set upper limit (85℃), or the water temperature of the solar collector is less than or equal to the water temperature of the hot water tank, the solar control cabinet controls the first water pump to stop and the second valve assembly on the third water pipe to close.

[0040] (3) Circulation control between the hot water tank and the constant temperature water tank

[0041] When the water temperature of the constant temperature water tank is less than or equal to the set lower limit of the constant temperature water tank, and the water temperature of the hot water tank minus the water temperature of the constant temperature water tank is greater than or equal to the third temperature difference threshold (5℃), the solar control cabinet controls the second water pump to start. During this period, if the water temperature of the constant temperature water tank is greater than or equal to the set upper limit of the constant temperature water tank, the solar control cabinet controls the second water pump to stop.

[0042] (4) Control of standby heating device

[0043] Between 8:00 AM and 4:00 PM, if the water temperature in the constant temperature water tank is ≥ the set first start-up temperature (43℃), the solar control cabinet will control the backup heating device to stop.

[0044] If the water temperature in the constant temperature water tank is less than the set first start temperature, first determine if the water temperature of the solar collector is greater than the set direct supply temperature. If the water temperature of the solar collector is greater than the set direct supply temperature, the solar control cabinet first controls the first water pump to start and the second valve assembly on the fourth water pipe to open, so that the hot water from the solar collector flows directly into the constant temperature water tank. When the water temperature in the constant temperature water tank is still lower than the set first start temperature within the set time, the solar control cabinet controls the backup heating device to start, and the backup heating device controls the third water pump to start, until the water temperature in the constant temperature water tank is greater than or equal to the set first start temperature. Then, the backup heating device controls the third water pump to stop, and the solar control cabinet controls the backup heating device to stop.

[0045] From 4 PM to 10 PM, if the water temperature in the constant temperature water tank is less than the set second start temperature (55℃), the solar control cabinet will control the backup heating device to run, and the backup heating device will control the third water pump to start. When the water temperature in the constant temperature water tank is greater than or equal to the set second start temperature, the solar control cabinet will control the backup heating device to stop, and the backup heating device will control the third water pump to stop.

[0046] Between 10 PM and 6 AM, if the water temperature in the hot water tank is less than the set second start-up temperature, the solar control cabinet will start the backup heating device and the second water pump, and the backup heating device will control the third water pump to run until the water temperature in the hot water tank is greater than or equal to the set second start-up temperature. Then, the solar control cabinet will stop the backup heating device and the second water pump, and the backup heating device will control the third water pump to stop.

[0047] The above description is merely a preferred embodiment of the present invention. It should be noted that for those skilled in the art, other parts not specifically described are existing technology or common knowledge. Several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A control method for a hot water system that maximizes the utilization of solar energy, characterized in that, The hot water system includes a hot water collection tank, a constant temperature water tank, and several solar collectors. The hot water collection tank is connected to a cold water source via a first water pipe and to the solar collectors via a second water pipe. A first water pump and a first valve assembly are installed on the second water pipe. The solar collectors are connected to the hot water collection tank and the constant temperature water tank via third and fourth water pipes, respectively. Second valve assemblies are connected to the third and fourth water pipes. A fourth and fifth water pipe connect the hot water collection tank and the constant temperature water tank. The fourth water pipe is connected to the second water pump and the third valve assembly. The constant temperature water tank is connected to a backup heating system via a sixth water pipe. The device has an inlet connection, a third water pump and a fourth valve assembly on the sixth water pipe, an outlet of the standby heating device connected to a constant temperature water tank via a seventh water pipe, a constant temperature water tank connected to a hot water supply area via an eighth water pipe, a first temperature sensor connected to the solar collector, a second temperature sensor on the hot water collection tank, and a third temperature sensor on the constant temperature water tank. The first water pump, the second water pump, the second valve assembly, the first temperature sensor, the second temperature sensor, the third temperature sensor, and the standby heating device are all connected to the solar control cabinet, and the third water pump is connected to the standby heating device. The control method includes: (1) Water replenishment at low water levels When the water level in the hot water tank is lower than the set lower limit of the water level in the hot water tank, the solar control cabinet controls the fifth valve assembly to open; when the water level in the hot water tank reaches the water level in the hot water tank, it controls the fifth valve assembly to close. When the water level in the constant temperature water tank is lower than the set lower limit, the solar control cabinet controls the fifth valve assembly to open, and cold water is added into the hot water collection tank. Then, it overflows into the constant temperature water tank through the fifth water pipe between the hot water collection tank and the constant temperature water tank. When the water level in the constant temperature water tank reaches the upper limit, the solar control cabinet controls the fifth valve assembly to close. (2) Control of solar collectors When the water temperature of the solar collector minus the water temperature of the hot water tank is greater than or equal to the first temperature difference threshold, the solar control cabinet controls the first water pump to start and the second valve assembly on the third water pipe to open. During this period, if the water level of the hot water tank is lower than the set lower limit, or the temperature of the hot water tank reaches the set upper limit, or the water temperature of the solar collector minus the water temperature of the hot water tank is less than or equal to the second temperature difference threshold, the solar control cabinet controls the first water pump to stop and the second valve assembly on the third water pipe to close. (3) Circulation control between hot water tank and constant temperature water tank When the water temperature in the constant temperature water tank is less than or equal to the set lower limit of the constant temperature water tank, and the water temperature in the hot water tank minus the water temperature in the constant temperature water tank is greater than or equal to the third temperature difference threshold, the solar control cabinet controls the second water pump to start. During this period, if the water temperature in the constant temperature water tank is greater than or equal to the set upper limit of the constant temperature water tank, the solar control cabinet controls the second water pump to stop. (4) Control of standby heating device Between 8:00 AM and 4:00 PM, if the water temperature in the constant temperature water tank is greater than or equal to the set first start-up temperature, the solar control cabinet will control the backup heating device to stop. If the water temperature in the constant temperature water tank is less than the set first start temperature, first determine whether the water temperature of the solar collector is greater than the set direct supply temperature. If the water temperature of the solar collector is greater than the set direct supply temperature, the solar control cabinet first controls the first water pump to start and the second valve assembly on the fourth water pipe to open, so that the hot water from the solar collector flows directly into the constant temperature water tank. When the water temperature in the constant temperature water tank is still lower than the set first start temperature within the set time, the solar control cabinet controls the backup heating device to start, and the backup heating device controls the third water pump to start, until the water temperature in the constant temperature water tank is greater than or equal to the set first start temperature. Then, the backup heating device controls the third water pump to stop, and the solar control cabinet controls the backup heating device. From 4 PM to 10 PM, if the water temperature in the constant temperature water tank is less than the set second start temperature, the solar control cabinet will control the backup heating device to run, and the backup heating device will control the third water pump to start. When the water temperature in the constant temperature water tank is greater than or equal to the set second start temperature, the solar control cabinet will control the backup heating device to stop, and the backup heating device will control the third water pump to stop. Between 10 PM and 6 AM, if the water temperature in the hot water tank is less than the set second start-up temperature, the solar control cabinet will start the backup heating device and the second water pump, and the backup heating device will control the third water pump to run until the water temperature in the hot water tank is greater than or equal to the set second start-up temperature. Then, the solar control cabinet will stop the backup heating device and the second water pump, and the backup heating device will control the third water pump to stop.

2. The control method for a hot water system that maximizes the utilization of solar energy according to claim 1, characterized in that, The hot water tank is also equipped with a first liquid level sensor, and the constant temperature water tank is equipped with a second liquid level sensor.

3. The control method for a hot water system that maximizes the utilization of solar energy according to claim 1, characterized in that, The second water pipe is equipped with a fourth temperature sensor.

4. The control method for a hot water system that maximizes the utilization of solar energy according to claim 1, characterized in that, The backup heating device is a heat pump type backup heating device.

5. The control method for a solar energy-maximizing hot water system according to claim 1, characterized in that, The cold water source is tap water, and a fifth valve assembly is installed on the first water pipe. The fifth valve assembly is connected to the solar control cabinet.

6. The control method for a hot water system that maximizes the utilization of solar energy according to claim 1, characterized in that, The eighth water pipe is equipped with a fourth water pump and a sixth valve assembly, and the fourth water pump is connected to the solar control cabinet.

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