Agricultural facility heat supply system using low-grade heat source and working method

Abstract

The application discloses an agricultural facility heat supply system using low-grade heat sources and a working method thereof. The system comprises low-grade waste heat, a heat storage device, facility agriculture, a water source heat pump, a heat source circulating pump, a heat supply circulating pump, a heat release circulating pump, a terminal heat dissipation device, an electric valve, a check valve and a temperature sensor. The low-grade waste heat, the heat source circulating pump and the water source heat pump form a heat source side circulating loop on the heat source side. One branch of the heat supply side of the water source heat pump is connected with the heat storage device through the electric valve, and the other branch is connected with the terminal heat dissipation device, thereby forming a main circulating loop on the heat supply side. The working method comprises detecting the water temperature of the low-grade waste heat, and automatically switching the water source heat pump heat supply mode, the water source heat pump heat supply and heat storage mode and the heat storage device heat supply mode according to the water temperature range. The application solves the problem that the existing heat supply system lacks the ability to flexibly adjust the heat supply mode according to the waste heat discharge state, thereby causing unstable heat supply or energy waste.

Description

Technical Field

[0001] This invention belongs to the field of heat exchange system technology, specifically relating to an agricultural facility heating system and its working method that utilizes a low-grade heat source. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] Agricultural facilities require high heating stability. Traditional heating methods rely on coal, gas, or electricity, resulting in high energy consumption and operating costs. Industrial production processes generate a large amount of low-grade waste heat, with water temperatures typically between 20°C and 45°C. Due to the low temperature, direct use for heating is inefficient, leading to significant waste. Furthermore, industrial waste heat emissions are intermittent and unstable, fluctuating greatly with production loads, making it impossible to directly and stably heat agricultural facilities. Existing heating systems lack the ability to flexibly adjust heating methods based on waste heat emission status. When waste heat is abundant, excess heat cannot be effectively stored; when waste heat is insufficient, there is a lack of backup heat sources, leading to unstable heating or energy waste. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides an agricultural facility heating system and its operating method that utilizes a low-grade heat source, solving the problem of unstable heating or energy waste caused by the lack of ability of existing heating systems to flexibly adjust the heating mode according to the waste heat emission status.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution: In a first aspect, the present invention provides an agricultural facility heating system utilizing a low-grade heat source, comprising a low-grade waste heat source, a heat storage device, facility agriculture, a water source heat pump, a heat source circulation pump, a heating circulation pump, a heat release circulation pump, terminal heat dissipation equipment, a first electric valve, a second electric valve, a third electric valve, a fourth electric valve, a check valve, and multiple temperature sensors; the low-grade waste heat source and the heat source circulation pump form a heat source-side circulation loop with the heat source side of the water source heat pump; the heating-side inlet of the water source heat pump is connected to the first electric valve through the heating circulation pump, the hot water outlet of the heat storage device is connected to the third electric valve, the first electric valve is connected to the third electric valve, the end of the third electric valve away from the heat storage device is connected to the outlet of the terminal heat dissipation equipment, and the inlet of the terminal heat dissipation equipment is connected to the heating-side outlet of the water source heat pump, forming a heating-side main circulation loop; the outlet of the water source heat pump is diverted via a three-way valve, with a portion of the heat source entering the terminal heat dissipation equipment in the facility agriculture, and then... The outlet of the terminal equipment connects to the first electric valve and the heating circulating water pump, forming a heating loop. Another portion of the heat source from the outlet of the water source heat pump, after being diverted via a three-way valve, enters the heat storage device for heat storage after passing through the second electric valve. The hot water outlet of the heat storage device connects to the third electric valve. Before entering the first electric valve, it merges with the low-temperature heat source from the outlet of the terminal heat dissipation equipment in the facility agriculture, and together they enter the inlet of the heating circulating water pump. After being pressurized by the circulating water pump, they enter the water source heat pump for reheating, forming a heat storage loop. The hot water outlet of the heat storage device sequentially connects to the second electric valve, the terminal heat dissipation equipment, the heat release circulating pump, the end of the first electric valve closest to the third electric valve, and a check valve, finally reaching the heat storage device, forming a heat release loop. The fourth electric valve connects to the inlet and outlet of the terminal heat dissipation equipment at both ends, respectively. Temperature sensors are respectively installed at the low-grade waste heat location, the outlet of the water source heat pump on the heating side, the return end of the terminal heat dissipation equipment, inside the facility agriculture, at the top of the heat storage device, and at the bottom of the heat storage device.

[0006] Furthermore, it also includes a controller, which is electrically connected to the heat source circulation pump, the heating circulation pump, the heat release circulation pump, the first electric valve, the second electric valve, the third electric valve, the fourth electric valve, the water source heat pump, and multiple temperature sensors. The controller controls the start and stop of the heat source circulation pump, the heating circulation pump, the heat release circulation pump, each electric valve, and the water source heat pump according to the detection signals of the temperature sensors.

[0007] Secondly, the present invention also provides a method for operating an agricultural facility heating system utilizing a low-grade heat source, comprising: detecting the water temperature at the low-grade waste heat source; and determining the waste heat status based on the water temperature range at the low-grade waste heat source. When the controller detects that the water temperature displayed by the temperature sensor at the low-grade waste heat source is in the medium temperature range, the water source heat pump heating is in operation mode. When the controller detects that the water temperature displayed by the temperature sensor at the low-grade waste heat area is in the high-temperature range, the water source heat pump operates in a mode of simultaneously supplying heat and storing heat. When the controller detects that the water temperature displayed by the temperature sensor at the low-grade waste heat source is in the low-temperature range, the heat storage device enters the heating operation mode to ensure continuous and stable heating for facility agriculture.

[0008] Furthermore, when the controller detects that the water temperature displayed by the temperature sensor at the low-grade waste heat source is in the medium temperature range, the controller controls the heat source circulation pump, heating circulation pump, water source heat pump, first electric valve and terminal heat dissipation equipment to open, controls the heat release circulation pump, second electric valve and third electric valve to close, and controls the water source heat pump to make the supply water temperature higher than the return water temperature.

[0009] Furthermore, when the controller detects that the water temperature displayed by the temperature sensor at the low-grade waste heat location is in the high-temperature range, the controller controls the heat source circulation pump, heating circulation pump, water source heat pump, first electric valve, second electric valve, third electric valve, and terminal heat dissipation equipment to open, controls the heat release circulation pump to close, closes the check valve, and controls the water source heat pump to make the supply water temperature higher than the return water temperature. Part of the high-temperature supply water output by the water source heat pump enters the heat storage device for heat storage through the second electric valve, and the other part enters the terminal heat dissipation equipment for heat supply. When the temperature sensor at the bottom of the heat storage device detects that the water temperature has reached the first temperature threshold, the controller controls the second electric valve and the third electric valve to close, ending the heat storage.

[0010] Furthermore, when the controller detects that the water temperature displayed by the temperature sensor at the low-grade waste heat source is in the low-temperature range, the controller controls the heat source circulation pump, heating circulation pump, water source heat pump, first electric valve, and third electric valve to close, and the second electric valve to open. It also controls the heat release circulation pump and the terminal heat dissipation equipment to start, and the check valve to open. The high-temperature hot water in the heat storage device is transported to the terminal heat dissipation equipment for heating through the heat release circulation pump and the check valve. The controller adjusts the circulation flow rate of the heat release circulation pump to make the supply water temperature higher than the return water temperature. When the temperature sensor at the top of the heat storage device detects that the water temperature has reached the second temperature threshold, the controller controls the second electric valve and the heat release circulation pump to close, ending the heat release.

[0011] Furthermore, the fourth electric valve adjusts the water flow rate entering the terminal heat dissipation equipment based on the temperature sensor detection signal within the facility agriculture.

[0012] Furthermore, the medium temperature range refers to the water temperature detected by the temperature sensor at the low-grade waste heat treatment area, which is between 20°C and 45°C; the controller controls the start of the water source heat pump to keep the supply water temperature at 55°C and the return water temperature at 45°C.

[0013] Furthermore, the high-temperature range is defined as a water temperature ≥45℃ detected by the temperature sensor at the low-grade waste heat treatment area; the controller controls the start of the water source heat pump to control the supply water temperature at 75℃ and the return water temperature at 60℃; the first temperature threshold is 75℃.

[0014] Furthermore, the low-temperature range is defined as a water temperature ≤20℃ detected by the temperature sensor at the low-grade waste heat treatment area; the controller adjusts the circulation flow rate of the heat release circulation pump to control the supply water temperature at 75℃ and the return water temperature at 45℃; the second temperature threshold is 45℃.

[0015] Compared with the prior art, the advantages and positive effects of this invention are: This invention achieves efficient utilization and flexible scheduling of low-grade waste heat through a combination of a water source heat pump and a thermal storage device. The water source heat pump raises the low-grade waste heat to a usable heating temperature, solving the problem that the temperature of low-grade waste heat is too low to be directly used for heating. The thermal storage device stores excess heat when there is sufficient waste heat and releases the stored heat when there is insufficient waste heat, realizing the time transfer and peak shaving of waste heat, overcoming the problem of unstable heating caused by the intermittent emission of industrial waste heat. This transforms previously wasted low-grade waste heat into a stable and reliable heating source, significantly reducing the heating energy consumption and operating costs of facility agriculture.

[0016] This invention employs multi-temperature sensor joint control, offering three operating modes: a water source heat pump heating mode to fully utilize medium-temperature waste heat; a water source heat pump heating with heat storage mode to store excess heat while meeting current heating needs; and a heat storage device heating mode to release stored heat and ensure continuous heating. The automatic switching between these three modes requires no manual intervention. The system can flexibly adjust the heating method based on fluctuations in waste heat emissions, ensuring heating stability and avoiding energy waste. Temperature sensors at the bottom and top of the heat storage device monitor the heat storage and release processes respectively, automatically ending either process when a set threshold is reached, achieving precise control of the heat storage device. Water supply and return temperature sensors in the terminal heat dissipation equipment monitor the heating effect in real time. The controller adjusts the output of the water source heat pump or the flow rate of the heat release circulation pump based on temperature feedback to ensure stable heating temperature. A room temperature sensor within the facility agriculture provides feedback signals to the fourth electric valve, achieving precise matching of the heating capacity with the actual heat load. This multi-sensor joint control mechanism makes the system highly intelligent and automated, significantly improving its adaptability to complex operating conditions and operational reliability. Attached Figure Description

[0017] The accompanying drawings, which form part of this invention, 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 improper limitation of the invention.

[0018] Figure 1 This is a schematic diagram of the agricultural facility heating system of the present invention; Figure 2 This is a schematic diagram of the water source heat pump heating mode of the present invention; Figure 3This is a schematic diagram of the water source heat pump heating and heat storage mode of the present invention; Figure 4 This is a schematic diagram of the heat supply mode of the heat storage device of the present invention.

[0019] In the diagram: 1. Low-grade waste heat; 2. Heat storage device; 3. Facility agriculture; 4. Water source heat pump; 5. Heat source circulation pump; 6. Heating circulation pump; 7. Heat release circulation pump; 8. Terminal heat dissipation equipment; 9. First electric valve; 10. Second electric valve; 11. Third electric valve; 12. Fourth electric valve; 13. Check valve; 14. Heat source resistance thermometer; 15. Return water resistance thermometer; 16. Supply water resistance thermometer; 17. Indoor air resistance thermometer; 18. Hot end resistance thermometer of heat storage device; 19. Cold end resistance thermometer of heat storage device. Detailed Implementation

[0020] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0021] 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 scope of exemplary embodiments according to the invention. As used herein, unless otherwise expressly indicated by the invention, the singular form is intended to include the plural form as well. 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.

[0022] Example 1 This embodiment provides an agricultural facility heating system that utilizes a low-grade heat source, such as... Figure 1 As shown, it includes low-grade waste heat 1, heat storage device 2, facility agriculture 3, water source heat pump 4, heat source circulation pump 5, heating circulation pump 6, heat release circulation pump 7, terminal heat dissipation equipment 8, first electric valve 9, second electric valve 10, third electric valve 11, fourth electric valve 12, check valve 13, multiple temperature sensors, and pipelines connecting the above components.

[0023] The heat source inlet of the water source heat pump 4 is connected to the outlet of the heat source circulation pump 5 via a first pipe. The inlet of the heat source circulation pump 5 is connected to the outlet of the low-grade waste heat 1 via a second pipe. The inlet of the low-grade waste heat 1 is connected to the heat source outlet of the water source heat pump 4 via a third pipe, forming a heat source-side circulation loop. The function of this circulation loop is to allow the hot water in the low-grade waste heat 1 to circulate through the evaporator of the water source heat pump 4. The water source heat pump 4 absorbs heat from the low-grade waste heat 1, and after raising the heat grade through refrigerant circulation, outputs high-temperature hot water.

[0024] The outlet of the water source heat pump 4 on the heating side is connected to the outlet of the heating circulation pump 6 via the fourth pipe. The inlet of the heating circulation pump 6 is connected to the first electric valve 9 via the fifth pipe. The second electric valve 10 is connected to the hot water inlet of the heat storage device 2 via the sixth pipe. The cold water inlet of the heat storage device 2 is connected to the third electric valve 11 via the seventh pipe. The first electric valve 9 is connected to the third electric valve 11 via the eighth pipe. The third electric valve 11 is connected to the outlet of the terminal heat dissipation device 8 via the ninth pipe. The inlet of the terminal heat dissipation device 8 is connected to the inlet of the water source heat pump 4 on the heating side via the tenth pipe. The tenth pipe is connected to the second electric valve 10, forming the main circulation loop on the heating side. The function of this circulation loop is to transport the high-temperature hot water output by the water source heat pump 4 to the terminal heat dissipation device 8 to provide heating for the facility agriculture 3, or to divert some of the high-temperature hot water into the heat storage device 2 for storage when there is sufficient waste heat.

[0025] The cold water inlet of the heat storage device 2 is connected to check valve 13 via the eleventh pipe, the outlet of the heat release circulation pump 7 is connected to check valve 13 via the twelfth pipe, and the inlet of the heat release circulation pump 7 is connected to the first electric valve 9 via the thirteenth pipe, forming a heat release branch of the heat storage device. The function of this branch is to allow the high-temperature hot water stored in the heat storage device 2 to flow out from the hot water inlet when the residual heat is insufficient, and enter the terminal heat dissipation device 8 through the second electric valve 10 for heating. The low-temperature water is then returned from the terminal heat dissipation device 8 to the cold water inlet of the heat storage device 2 via check valve 13 by the heat release circulation pump 7.

[0026] The fourth electric valve 12 is installed on the fourteenth pipeline and is used to regulate the water supply flow into the terminal heat dissipation device 8. The fourth electric valve 12 dynamically adjusts the hot water flow based on the deviation between the actual room temperature and the set temperature in the facility agriculture 3, so as to achieve a precise match between the heat supply and the actual heat load.

[0027] Temperature sensors include a heat source RTD 14, a supply water RTD 15, a return water RTD 16, an indoor air RTD 17, a hot-end RTD 18 of the heat storage device, and a cold-end RTD 19 of the heat storage device, and are respectively installed in different locations in the system: the heat source RTD 14 is installed on the outlet water pipe of the low-grade waste heat 1 to monitor the water temperature T14 of the low-grade waste heat 1 and determine the waste heat status; the supply water RTD 15 is installed at the outlet water of the water source heat pump 4 on the heating side to monitor the supply water temperature T15; the return water RTD 16 is installed at the return water end of the terminal heat dissipation device 8 to monitor the return water temperature T16; the indoor air RTD 17 is installed inside the facility agriculture 3 to monitor the room temperature T17; the hot-end RTD 18 of the heat storage device is installed on the top of the heat storage device 2 to monitor the water temperature T18 at the top of the heat storage device 2; and the cold-end RTD 19 of the heat storage device is installed at the bottom of the heat storage device 2 to monitor the water temperature T19 at the bottom of the heat storage device 2. These temperature sensors provide real-time temperature data for the intelligent control of the system.

[0028] The system also includes a controller, which is electrically connected to the heat source circulation pump 5, the heating circulation pump 6, the heat release circulation pump 7, the first electric valve 9, the second electric valve 10, the third electric valve 11, the fourth electric valve 12, the water source heat pump 4, and multiple temperature sensors. Based on the detection signals from the temperature sensors, the controller automatically determines the waste heat status and switches operating modes, controlling the start / stop and operating parameters of each device to achieve intelligent and automated system operation.

[0029] Example 2 This embodiment provides a working method for an agricultural facility heating system utilizing a low-grade heat source, including: detecting the water temperature at the low-grade waste heat source; and determining the waste heat status based on the water temperature range at the low-grade waste heat source. When the controller detects that the water temperature displayed by the temperature sensor at the low-grade waste heat source is in the medium temperature range, the water source heat pump heating is in operation mode. When the controller detects that the water temperature displayed by the temperature sensor at the low-grade waste heat area is in the high-temperature range, the water source heat pump operates in a mode of simultaneously supplying heat and storing heat. When the controller detects that the water temperature displayed by the temperature sensor at the low-grade waste heat source is in the low-temperature range, the heat storage device enters the heating operation mode to ensure continuous and stable heating for facility agriculture.

[0030] Specifically, when industrial waste heat is not significantly discharged, and the water temperature of the low-grade waste heat 1 detected by the heat source resistance 14 is in the medium temperature range, i.e., 20℃ < T14 < 45℃, the controller determines that the waste heat is moderate and adopts the water source heat pump heating operation mode, such as... Figure 2 As shown.

[0031] In this mode, the controller controls the opening of the heat source circulation pump 5, the heating circulation pump 6, the water source heat pump 4, the first electric valve 9, and the terminal heat dissipation device 8, and controls the closing of the heat release circulation pump 7, the second electric valve 10, and the third electric valve 11. At this time, the hot water in the low-grade waste heat 1 circulates through the heat source side of the water source heat pump 4 under the drive of the heat source circulation pump 5. The water source heat pump 4 absorbs heat from the low-grade waste heat 1 and outputs high-temperature hot water on the heating side. Driven by the heating circulation pump 6, the high-temperature hot water flows to the terminal heat dissipation device 8, releases heat in the terminal heat dissipation device 8 to provide heat for the facility agriculture 3, and then returns to the heating side inlet of the water source heat pump 4 through the first electric valve 9, forming a closed loop.

[0032] The supply water resistance thermometer 15 monitors the supply water temperature T15 of the water source heat pump 4 in real time, and the return water resistance thermometer 16 monitors the return water temperature T16 of the pipeline in real time. Based on the real-time data of T15 and T16, the controller adjusts the compressor power of the water source heat pump 4 to precisely control the supply water temperature T15 to around 55℃ and the return water temperature T16 to around 45℃, ensuring stable heating performance. The fourth electric valve 12 further adjusts the water supply flow into the terminal heat dissipation device 8 based on the room temperature T17 displayed by the indoor air resistance thermometer 17 installed in the facility agriculture 3. When the room temperature T17 is lower than the set value, the opening of the fourth electric valve 12 decreases, increasing the heating capacity by reducing the bypass flow; when the room temperature T17 is higher than the set value, the opening of the fourth electric valve 12 increases, decreasing the heating capacity by increasing the bypass flow, ensuring that the room temperature T17 remains stable within a reasonable range, meeting the indoor temperature requirements of the crops in the facility agriculture 3.

[0033] The water source heat pump 4 fully utilizes the ability to upgrade low-grade waste heat, raising the temperature of low-temperature hot water (20℃ to 45℃) to approximately 55℃, thus converting previously unusable low-temperature waste heat into a usable heating source and significantly improving waste heat utilization efficiency. The controller precisely controls the heating temperature through temperature feedback, ensuring the stability of the heating effect.

[0034] When a large amount of industrial waste heat is emitted, and the heat source resistance 14 detects that the water temperature of the low-grade waste heat 1 is in the high-temperature range, i.e., T14≥45℃, the controller determines that the waste heat is sufficient and adopts a water source heat pump heating and heat storage operation mode. Figure 3 As shown.

[0035] In this mode, the controller controls the opening of the heat source circulation pump 5, the heating circulation pump 6, the water source heat pump 4, the first electric valve 9, the second electric valve 10, the third electric valve 11, and the terminal heat dissipation device 8, and controls the closing of the heat release circulation pump 7. The check valve 13 automatically closes when impacted by reverse water flow. At this time, the water source heat pump 4 operates at a higher power, raising the low-grade waste heat 1 to a high-temperature water supply of approximately 75°C. The water supply resistance thermometer 15 monitors the water supply temperature T15 of the water source heat pump 4 in real time, and the return water resistance thermometer 16 monitors the water supply temperature T16 of the pipeline in real time. The controller precisely controls the water supply temperature T15 to approximately 75°C and the return water temperature T16 to approximately 60°C by adjusting the power of the water source heat pump 4.

[0036] The high-temperature water supply is divided into two paths under the control of the second electric valve 10 and the first electric valve 9: one path enters the heat storage device 2 through the second electric valve 10 for heat storage, realizing the time transfer of waste heat and peak shaving; the other path enters the terminal heat dissipation device 8 for heating to meet the current heating demand. The cold end thermal resistor 19 of the heat storage device monitors the water temperature T19 at the bottom of the heat storage device 2 in real time. When T19 reaches the first temperature threshold of 75℃, it indicates that the heat storage device 2 is full of high-temperature hot water, the heat storage process ends, and the controller automatically controls the second electric valve 10 and the third electric valve 11 to close, avoiding energy waste. The fourth electric valve 12 further adjusts the water supply flow into the terminal heat dissipation device 8 according to the room temperature T17 displayed by the indoor air thermal resistor 17 installed in the facility agriculture 3, ensuring that the room temperature T17 is stable within a reasonable range and meets the indoor temperature requirements of the crops in the facility agriculture 3.

[0037] This model fully utilizes excess heat during periods of abundant waste heat, storing it as sensible heat in the heat storage device 2 to provide a backup heat source during periods of insufficient waste heat, significantly improving the system's adaptability to intermittent waste heat. Simultaneously, it meets current heating demands, achieving efficient utilization and flexible scheduling of waste heat.

[0038] When industrial waste heat is not emitted or is emitted in very small amounts, and the water temperature of the low-grade waste heat 1 detected by the heat source resistance 14 is in the low-temperature range, i.e., T14≤20℃, the controller determines that the waste heat is insufficient and adopts the heat storage device heating operation mode. Figure 4 As shown.

[0039] In this mode, the controller closes the heat source circulation pump 5, the heating circulation pump 6, the water source heat pump 4, the first electric valve 9, and the third electric valve 11, and opens the second electric valve 10, controlling the heat release circulation pump 7 and the terminal heat dissipation device 8 to start. The check valve 13 automatically opens under the impact of the forward water flow, allowing the high-temperature hot water in the heat storage device 2 to flow to the terminal heat dissipation device 8. At this time, the high-temperature hot water stored in the heat storage device 2 flows out from the hot water outlet of the heat storage device 2, enters the terminal heat dissipation device 8 through the second electric valve 10, and releases heat in the terminal heat dissipation device 8 to provide heat for facility agriculture 3. The cooled heat source enters the inlet of the heat release circulation pump 7, and under the drive of the heat release circulation pump 7, it is transported from the outlet of the heat release circulation pump 7 through the check valve 13 to the heat storage device 2, completing the heat storage device's heating operation mode.

[0040] The supply water resistance thermometer 15 monitors the supply water temperature T15 of the heat storage device 2 in real time, and the return water resistance thermometer 16 monitors the return water temperature T16 of the pipeline in real time. The controller precisely controls the supply water temperature T15 to around 75℃ and the return water temperature T16 to around 45℃ by adjusting the speed and total circulation flow of the heat release circulation pump 7, ensuring the heating effect. The fourth electric valve 12 further adjusts the water supply flow into the terminal heat dissipation device 8 based on the room temperature T17 displayed by the indoor air resistance thermometer 17 installed in the facility agriculture 3, ensuring that the room temperature T17 is stable within a reasonable range and meets the indoor temperature requirements of the crops in the facility agriculture 3.

[0041] The thermal resistance 18 at the hot end of the thermal storage device monitors the water temperature T18 at the top of the thermal storage device 2 in real time. When T18 reaches the second temperature threshold of 45℃, it indicates that the high-temperature hot water in the thermal storage device 2 has been basically released and the heat release process has ended. The controller automatically controls the second electric valve 11 and the heat release circulation pump 7 to close, so as to prevent low-temperature water from entering the heating system and affecting the heating effect.

[0042] This mode realizes the peak-shaving and valley-filling function of the thermal storage device 2, releasing the stored heat during periods of insufficient waste heat, ensuring the continuity and stability of heating supply, and avoiding heating interruptions caused by intermittent waste heat discharge. The system relies entirely on the high-temperature hot water stored in the thermal storage device 2 for heating, without the need to start the water source heat pump 4, thus saving energy consumption.

[0043] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. An agricultural facility heating system utilizing a low-grade heat source, characterized in that, This system includes low-grade waste heat storage, a heat storage device, facility agriculture, a water source heat pump, a heat source circulation pump, a heating circulation pump, a heat release circulation pump, terminal heat dissipation equipment, a first electric valve, a second electric valve, a third electric valve, a fourth electric valve, a check valve, and multiple temperature sensors. The low-grade waste heat storage and heat source circulation pump form a heat source-side circulation loop with the heat source side of the water source heat pump. The outlet of the water source heat pump on the heating side is connected to the first electric valve through the heating circulation pump. The cold water outlet of the heat storage device is connected to the third electric valve. The first electric valve is connected to the third electric valve. The end of the third electric valve furthest from the heat storage device is connected to the outlet of the terminal heat dissipation equipment. The inlet of the terminal heat dissipation device is connected to the heating side inlet of the water source heat pump, forming the main circulation loop on the heating side; the hot water outlet of the heat storage device is sequentially connected to the second electric valve, the terminal heat dissipation device in facility agriculture, the heat release circulation pump, and the check valve, wherein the heat release pump is connected to the end of the first electric valve near the third electric valve, forming a heat release branch; the two ends of the fourth electric valve are respectively connected to the inlet and outlet of the terminal heat dissipation device; the temperature sensors are respectively installed at the low-grade waste heat location, the heating side outlet of the water source heat pump, the return water end of the terminal heat dissipation device, inside the facility agriculture, at the top of the heat storage device, and at the bottom of the heat storage device.

2. The agricultural facility heating system utilizing a low-grade heat source according to claim 1, characterized in that, It also includes a controller, which is electrically connected to the heat source circulation pump, the heating circulation pump, the heat release circulation pump, the first electric valve, the second electric valve, the third electric valve, the fourth electric valve, the water source heat pump, and multiple temperature sensors. The controller controls the start and stop of the heat source circulation pump, the heating circulation pump, the heat release circulation pump, each electric valve, and the water source heat pump according to the detection signals of the temperature sensors.

3. The working method of an agricultural facility heating system utilizing a low-grade heat source according to any one of claims 1-2, characterized in that, include: Detect the water temperature at the low-grade waste heat source; The state of waste heat can be determined based on the water temperature range at the low-grade waste heat source. When the controller detects that the water temperature displayed by the temperature sensor at the low-grade waste heat source is in the medium temperature range, the water source heat pump heating is in operation mode. When the controller detects that the water temperature displayed by the temperature sensor at the low-grade waste heat area is in the high-temperature range, the water source heat pump operates in a mode of simultaneously supplying heat and storing heat. When the controller detects that the water temperature displayed by the temperature sensor at the low-grade waste heat source is in the low-temperature range, the heat storage device enters the heating operation mode to ensure continuous and stable heating for facility agriculture.

4. The working method of an agricultural facility heating system utilizing a low-grade heat source according to claim 3, characterized in that, When the controller detects that the water temperature displayed by the temperature sensor at the low-grade waste heat source is in the medium temperature range, the controller controls the heat source circulation pump, the heating circulation pump, the water source heat pump, the first electric valve and the terminal heat dissipation equipment to turn on, controls the heat release circulation pump, the second electric valve and the third electric valve to turn off, and controls the water source heat pump to make the supply water temperature higher than the return water temperature.

5. The working method of an agricultural facility heating system utilizing a low-grade heat source according to claim 3, characterized in that, When the controller detects that the water temperature displayed by the temperature sensor at the low-grade waste heat source is in the high-temperature range, the controller controls the heat source circulation pump, heating circulation pump, water source heat pump, first electric valve, second electric valve, third electric valve, and terminal heat dissipation equipment to start, controls the heat release circulation pump to stop, the check valve to stop, and controls the water source heat pump to make the supply water temperature higher than the return water temperature. Part of the high-temperature supply water output by the water source heat pump enters the heat storage device for heat storage through the second electric valve, and the other part enters the terminal heat dissipation equipment for heat supply. When the temperature sensor at the bottom of the heat storage device detects that the water temperature has reached the first temperature threshold, the controller controls the second electric valve and the third electric valve to stop the heat storage.

6. The working method of an agricultural facility heating system utilizing a low-grade heat source according to claim 3, characterized in that, When the controller detects that the water temperature displayed by the temperature sensor at the low-grade waste heat source is in the low-temperature range, the controller controls the heat source circulation pump, heating circulation pump, water source heat pump, first electric valve, and third electric valve to close, and the second electric valve to open. It also controls the heat release circulation pump and the terminal heat dissipation equipment to start, and the check valve to open. The high-temperature hot water in the heat storage device is transported to the terminal heat dissipation equipment for heating through the heat release circulation pump. The controller adjusts the circulation flow rate of the heat release circulation pump to make the supply water temperature higher than the return water temperature. When the temperature sensor at the top of the heat storage device detects that the water temperature has reached the second temperature threshold, the controller controls the second electric valve and the heat release circulation pump to close, ending the heat release.

7. The working method of an agricultural facility heating system utilizing a low-grade heat source according to claim 1, characterized in that, The fourth electric valve adjusts the water flow rate into the terminal heat dissipation equipment based on the temperature sensor detection signal within the facility agriculture.

8. The working method of an agricultural facility heating system utilizing a low-grade heat source according to claim 4, characterized in that, The medium temperature range is defined as the water temperature detected by the temperature sensor at the low-grade waste heat treatment area, which is between 20°C and 45°C. The controller controls the start of the water source heat pump to maintain the supply water temperature at 55°C and the return water temperature at 45°C.

9. The working method of an agricultural facility heating system utilizing a low-grade heat source according to claim 5, characterized in that, The high-temperature range is defined as a water temperature ≥45℃ detected by the temperature sensor at the low-grade waste heat treatment area; the controller controls the start of the water source heat pump to maintain the supply water temperature at 75℃ and the return water temperature at 60℃; the first temperature threshold is 75℃.

10. The working method of an agricultural facility heating system utilizing a low-grade heat source according to claim 6, characterized in that, The low-temperature range is defined as the water temperature detected by the temperature sensor at the low-grade waste heat treatment area being ≤20℃; the controller adjusts the circulation flow rate of the heat release circulation pump to control the supply water temperature at 75℃ and the return water temperature at 45℃; the second temperature threshold is 45℃.

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