Multi-energy hot water year-round supply system and method based on deep and shallow geothermal energy

Abstract

The invention discloses a multi-energy hot water annual supply system and method mainly using deep and shallow geothermal energy, and relates to the technical field of heat supply. In the system, a heat storage water tank, a hot water circulating pump, a water-water plate type heat exchanger, a heat recovery type ground source heat pump unit, an air source hot water unit and three electric switch valves are arranged; the primary side of the plate heat exchanger is connected into a middle-deep layer geothermal water supply pipeline and a tail water pipeline, and the hot water side is connected into the secondary side of the plate heat exchanger, the heat recoverer and the air source unit in parallel by the heat storage water tank through a distribution pipeline and flows back. And the controller determines an operation mode according to the seasonal working condition information, corresponding valves are opened in an interlocking mode to drive hot water to conduct circulating heat exchange / heating through the target branch, and when the temperature in the heat storage water tank is lower than a preset threshold value, the standby branch is switched to conduct compensation heating. By means of the technical scheme, multi-energy cooperation and tail water gradient utilization are achieved, stable water supply temperature and annual continuous supply are guaranteed, energy consumption and operation and maintenance cost are reduced, and the integration degree and reliability of the system are improved.

Description

Technical Field

[0001] This invention relates to the field of heating technology, and in particular to a multi-energy hot water supply system based on deep and shallow geothermal energy throughout the year, and a method for supplying multi-energy hot water based on deep and shallow geothermal energy throughout the year. Background Technology

[0002] Domestic hot water is a rigid energy demand for buildings and industrial parks, characterized by continuous supply throughout the year, specific water temperature requirements, and load fluctuations significantly affected by seasons and water usage behavior. To reduce operating costs and improve energy efficiency, engineering projects typically employ direct supply from medium-deep geothermal energy, shallow geothermal energy (ground source heat pump) heating / cooling systems to produce hot water, or use air source water heaters to handle the domestic hot water load independently.

[0003] In existing technologies, medium-deep geothermal energy can provide basic heat for domestic hot water through heat exchange. However, outside the heating season or under low-temperature conditions, geothermal heat exchange alone often fails to reliably meet the target supply temperature for domestic hot water. Simultaneously, the wastewater from medium-deep geothermal sources still carries usable heat, and conventional systems do not utilize this wastewater in a cascade manner, resulting in low overall energy efficiency. On the other hand, ground source heat pumps can recover condensate heat during the cooling season, but many solutions fail to effectively couple with the domestic hot water system, rendering the heat recovery value unrealizable. While air source water heaters offer the advantage of flexible deployment, their efficiency drops significantly at low ambient temperatures, leading to high electricity consumption if used as the primary heat source throughout the year.

[0004] In addition, multi-heat source combination schemes generally suffer from low system integration in engineering implementation: multiple heat exchange / heating equipment form their own loops, valves and pumps are redundantly configured, heat source switching relies on manual or simple start-stop logic, which can easily lead to loop crosstalk, unclear circulation organization, and difficulty in achieving the control objectives of prioritizing the main heat source and automatically supplementing heat when the temperature is insufficient, thus affecting the stability of water supply temperature and the economic efficiency of operation. Summary of the Invention

[0005] To address the aforementioned issues, this invention provides a multi-energy year-round hot water supply system and method primarily utilizing deep and shallow geothermal energy. A unified domestic hot water circuit is formed by a hot water storage tank and a hot water circulation pump. A water-to-water plate heat exchanger (medium-deep geothermal), a heat recovery ground source heat pump unit, and an air source hot water unit are connected in parallel. A controller selectively opens corresponding electric switching valves and interlocks to close other branches based on seasonal operating conditions. When the domestic hot water temperature in the storage tank fails to reach the preset supply temperature threshold, the system automatically switches to a backup branch for compensatory heating. This achieves year-round multi-energy synergy and tiered utilization, ensuring a continuous and stable supply of domestic hot water, improving supply temperature stability and overall energy efficiency, reducing power consumption and manual intervention, minimizing redundant configurations of multiple circuits, and enhancing system integration and operational reliability.

[0006] To achieve the above objectives, the present invention provides a multi-energy hot water supply system based on deep and shallow geothermal energy throughout the year, including a hot water storage tank, a hot water circulation pump, a water-to-water plate heat exchanger, a heat recovery ground source heat pump unit, an air source hot water unit, a first electric switch valve, a second electric switch valve, a third electric switch valve, and a controller. The primary side of the water-to-water plate heat exchanger is connected to the medium-deep geothermal water supply pipeline and the medium-deep geothermal tailwater pipeline. The outlet of the hot water storage tank is connected to the secondary inlet of the water-to-water plate heat exchanger, the heat recovery inlet of the heat recovery ground source heat pump unit, and the inlet of the air source hot water unit via distribution pipelines. The secondary outlet of the water-to-water plate heat exchanger is connected to the inlet of the hot water circulation pump via the first electric switch valve; the outlet of the heat recovery unit is connected to the inlet of the hot water circulation pump via the second electric switch valve; the outlet of the air source hot water unit is connected to the inlet of the hot water circulation pump via the third electric switch valve; and the outlet of the hot water circulation pump is connected to the inlet of the hot water storage tank. The controller is connected to the first electric switch valve, the second electric switch valve and the third electric switch valve, and is used to determine the operating mode according to seasonal operating condition information, and in the operating mode, open one of the first electric switch valve, the second electric switch valve or the third electric switch valve and close the other electric switch valves, so that hot water circulates through the target branch for heat exchange / heating and flows back to the hot water storage tank. The controller is also used to switch the operating mode to enable the backup branch to compensate for the heating of hot water when the hot water temperature in the hot water storage tank does not reach the preset hot water supply temperature threshold.

[0007] In the above technical solution, preferably, the outlet of the hot water storage tank is connected to the secondary side inlet of the water-to-water plate heat exchanger, the inlet of the heat recovery unit and the inlet of the air source hot water unit through a distribution pipeline; The secondary outlet of the water-to-water plate heat exchanger is connected to the inlet of the hot water circulation pump via the first electric switch valve; the outlet of the heat recovery unit is connected to the inlet of the hot water circulation pump via the second electric switch valve; and the outlet of the air source hot water unit is connected to the inlet of the hot water circulation pump via the third electric switch valve. The outlet of the hot water circulation pump is connected to the inlet of the hot water storage tank.

[0008] In the above technical solution, preferably, the hot water circulation pump is installed on the upper hot water inlet pipe of the hot water storage tank, and the secondary side inlet of the water-water plate heat exchanger is connected to the lower hot water outlet of the hot water storage tank.

[0009] In the above technical solution, preferably, the controller is used to open the first electric switch valve and close the second electric switch valve and the third electric switch valve in the heating season mode, so that the hot water flows back to the hot water storage tank after heat exchange on the secondary side of the water-water plate heat exchanger. Furthermore, when the temperature of the hot water in the hot water storage tank is lower than the preset hot water supply temperature threshold, the controller controls the first electric switch valve to close and the third electric switch valve to open, so that the hot water is returned to the hot water storage tank after being compensated and heated by the air source hot water unit.

[0010] In the above technical solution, preferably, the preset hot water supply temperature threshold is 45℃ or 50℃; and, in the heating season mode, when the geothermal water temperature in the medium-deep geothermal water supply pipeline is less than 50℃ and the hot water temperature in the hot water storage tank is lower than the preset hot water supply temperature threshold, the controller performs a switching control to close the first electric switch valve and open the third electric switch valve.

[0011] In the above technical solution, preferably, the medium-deep geothermal tailwater after heat exchange in the water-water plate heat exchanger is configured as the heat source input of the heat recovery ground source heat pump unit under heating conditions.

[0012] In the above technical solution, preferably, the controller is used to open the second electric switch valve and close the first electric switch valve and the third electric switch valve in the cooling season mode, so that the hot water is heated by the heat recovery unit and then flows back to the hot water storage tank. When the hot water temperature in the hot water storage tank does not reach the preset hot water supply temperature threshold, the third electric switch valve is switched on and the other electric switch valves are closed, so that the hot water is returned to the hot water storage tank after being compensated and heated by the air source hot water unit.

[0013] In the above technical solution, preferably, the heat recovery ground source heat pump unit includes the heat recovery unit, as well as the condenser and the evaporator. The heat recovery unit is connected to the hot water circulation loop to heat the hot water, the evaporator is connected to the indoor terminal refrigeration pipeline, and the condenser is connected to the outdoor buried pipe heat exchanger.

[0014] In the above technical solution, preferably, the controller is used to open the third electric switch valve and close the first electric switch valve and the second electric switch valve in the non-cooling and heating season mode, so that the hot water is heated by the air source water heater and then flows back to the hot water storage tank. When the hot water temperature in the hot water storage tank does not reach the preset hot water supply temperature, the second electric switch valve is switched on and the other electric switch valves are closed, so that the hot water is returned to the hot water storage tank after being compensated and heated by the heat recovery unit.

[0015] This invention also proposes a method for year-round supply of multi-energy hot water primarily based on deep and shallow geothermal energy, applicable to a year-round supply system for multi-energy hot water primarily based on deep and shallow geothermal energy disclosed in any of the above technical solutions, comprising: Obtain seasonal operating condition information and determine the operating mode; In the heating season mode, the first electric switch valve is opened and the second and third electric switch valves are closed, so that the hot water flows back to the hot water storage tank after heat exchange through the water-to-water plate heat exchanger; when the hot water temperature in the hot water storage tank is lower than the preset hot water supply temperature threshold, the first electric switch valve is closed and the third electric switch valve is opened, so that the hot water flows back to the hot water storage tank after being compensated and heated by the air source hot water unit. In the cooling season mode, the second electric switch valve is opened and the first electric switch valve and the third electric switch valve are closed, so that the hot water is heated by the heat recovery unit and then flows back to the hot water storage tank; when the hot water temperature in the hot water storage tank is lower than the preset hot water supply temperature threshold, the second electric switch valve is closed and the third electric switch valve is opened, so that the hot water is compensated and heated by the air source hot water unit and then flows back to the hot water storage tank. In non-cooling and heating season mode, the third electric switch valve is opened and the first and second electric switch valves are closed, so that the hot water is heated by the air source water heater and then flows back to the hot water storage tank; when the hot water temperature in the hot water storage tank is lower than the preset hot water supply temperature threshold, the third electric switch valve is closed and the second electric switch valve is opened, so that the hot water is compensated and heated by the heat recovery unit and then flows back to the hot water storage tank.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) By forming a unified domestic hot water circulation loop with the hot water storage tank and the hot water circulation pump, and connecting the three branches of the water-to-water plate heat exchanger, the heat recovery unit of the heat recovery ground source heat pump unit and the air source hot water unit in parallel, and with the interlocking selection of the electric switch valve, the domestic hot water can switch the heat exchange / heating path as needed in the same loop. From the system architecture level, the risk of pipeline redundancy and crosstalk caused by multiple loops running in parallel is reduced, and the integration and operational reliability are improved.

[0017] (2) The controller determines the operating mode based on seasonal operating conditions. In the heating season, the deep geothermal heat exchange branch is selected first; in the cooling season, the ground source heat pump heat recovery branch is selected first; and in the non-cooling and heating season, the air source heating branch is selected first. This allows the most economical heat source to be matched for different seasons, increases the proportion of renewable energy and waste heat utilization, and reduces the overall energy consumption of the domestic hot water preparation process.

[0018] (3) By automatically switching to the backup branch for compensation heating when the domestic hot water temperature in the hot water storage tank does not reach the preset supply temperature threshold, the adaptive response to load fluctuations and heat source temperature fluctuations is realized, ensuring the continuity and stability of the domestic hot water supply temperature and reducing manual switching and operation management costs.

[0019] (4) By configuring the medium-deep geothermal tailwater after heat exchange in the water-water plate heat exchanger as the heat source input for the ground source heat pump heating operation, the cascade utilization of deep and shallow geothermal energy is realized, the waste heat recovery efficiency of medium-deep geothermal tailwater is improved, and the energy efficiency and economy of the system throughout the year are further enhanced. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the layout of a multi-energy hot water supply system based on deep and shallow geothermal energy, disclosed in one embodiment of the present invention.

[0021] In the diagram, the correspondence between the components and the reference numerals is as follows: 1. Water-to-water plate heat exchanger; 2. Heat recovery ground source heat pump unit; 3. Air source hot water unit; 4. Hot water circulation pump; 5. Hot water storage tank; 6. First electric switch valve; 7. Second electric switch valve; 8. Third electric switch valve; 2-1. Heat recovery unit; 2-2. Condenser; 2-3. Evaporator. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] The present invention will now be described in further detail with reference to the accompanying drawings: like Figure 1 As shown, a multi-energy hot water supply system based on deep and shallow geothermal energy provided by the present invention includes a hot water storage tank 5, a hot water circulation pump 4, a water-to-water plate heat exchanger 1, a heat recovery ground source heat pump unit 2, an air source hot water unit 3, a first electric switch valve 6, a second electric switch valve 7, a third electric switch valve 8, and a controller. The primary side of the water-to-water plate heat exchanger 1 is connected to the medium-deep geothermal water supply pipeline and the medium-deep geothermal tailwater pipeline. The outlet of the hot water storage tank 5 is connected to the secondary side inlet of the water-to-water plate heat exchanger 1, the inlet of the heat recovery unit 2-1 of the heat recovery ground source heat pump unit 2, and the inlet of the air source hot water unit 3 through the distribution pipeline. The secondary outlet of the water-to-water plate heat exchanger 1 is connected to the inlet of the hot water circulation pump 4 via the first electric switch valve 6. The outlet of the heat recovery unit 2-1 is connected to the inlet of the hot water circulation pump 4 via the second electric switch valve 7. The outlet of the air source hot water unit 3 is connected to the inlet of the hot water circulation pump 4 via the third electric switch valve 8. The outlet of the hot water circulation pump 4 is connected to the inlet of the hot water storage tank 5. The controller is connected to the first electric switch valve 6, the second electric switch valve 7 and the third electric switch valve 8, and is used to determine the operating mode according to the seasonal operating conditions information. In the operating mode, one of the first electric switch valve 6, the second electric switch valve 7 or the third electric switch valve 8 is opened and the remaining electric switch valves are closed, so that the hot water circulates through the target branch for heat exchange / heating and flows back to the hot water storage tank 5. The controller is also used to switch the operating mode to enable the backup branch to compensate for the heating of hot water when the hot water temperature in the hot water storage tank 5 does not reach the preset hot water supply temperature threshold.

[0024] During implementation, the system uses the hot water storage tank 5 as an energy buffer and convergence node on the hot water side, forming a closed-loop circulation circuit with the hot water circulation pump 4. The hot water from the storage tank 5 enters three parallel target branches via distribution pipelines: one branch enters the secondary side of the water-to-water plate heat exchanger 1, exchanging heat with the primary side's medium-deep geothermal water supply-tailwater pipeline; another branch enters the heat recovery unit 2-1 of the heat recovery ground source heat pump unit 2 to obtain recovered heat; and the third branch enters the air source hot water unit 3 for heating. The return water from the three branches converges into the inlet of the circulation pump via corresponding electric switching valves, and is then sent back to the storage tank 5 by the circulation pump, forming a single-pump driven, three-branch interlocked loop architecture. The system can be understood as including three types of circulation circuits: a medium-deep geothermal hot water circulation circuit, a ground source heat pump hot water circulation circuit, and an air source hot water circulation circuit. These three types of circuits converge and switch on the hot water side through the storage tank 5 and the hot water circulation pump 4.

[0025] The controller receives seasonal operating condition information to determine the operating mode. In the corresponding mode, it opens only one electric switch valve and closes the others, ensuring that hot water circulates and heats only through the selected target branch, avoiding cross-flow and energy conflict between branches. When the hot water temperature in the hot water storage tank 5 does not reach the preset hot water supply temperature threshold, the controller switches the operating mode to activate the backup branch for compensatory heating, ensuring continuous water supply and meeting the supply temperature standard throughout the year.

[0026] In this implementation, a valve-controlled switching strategy that prioritizes primary branches and uses backup branches as a fallback achieves year-round multi-energy synergy and tiered utilization, driven by seasonal operating conditions. This reduces the duration and amount of medium-deep geothermal water directly participating in hot water heat exchange throughout the year. It also selects more energy-efficient heat source paths in different seasons to reduce operational input, ensuring a continuous and stable supply of domestic hot water. This improves the stability of water supply temperature and overall energy efficiency, reduces electricity consumption and manual intervention, reduces redundant configuration of multiple circuits, improves system integration and operational reliability, enhances overall system energy efficiency and temperature stability, and reduces manual switching and operation and maintenance management costs.

[0027] In the above embodiments, preferably, the outlet of the hot water storage tank 5 is provided with a distribution pipeline as a parallel water supply header, which is connected to the secondary side inlet of the water-to-water plate heat exchanger 1, the inlet of the heat recovery unit 2-1 and the inlet of the air source hot water unit 3 respectively. The secondary outlet of the water-to-water plate heat exchanger 1 is connected to the inlet of the hot water circulation pump 4 via the first electric switch valve 6. The outlet of the heat recovery unit 2-1 is connected to the inlet of the hot water circulation pump 4 via the second electric switch valve 7. The outlet of the air source hot water unit 3 is connected to the inlet of the hot water circulation pump 4 via the third electric switch valve 8, forming a pipeline topology of parallel branch return water - valve-controlled confluence - single pump reinjection. The outlet of the circulation pump is uniformly connected back to the inlet of the hot water storage tank 5 to achieve closed-loop circulation.

[0028] In this embodiment, the piping arrangement ensures that the three branches have a consistent loop reference pressure differential under the same circulating pump drive. The interlocking selection of the electrically operated switching valves achieves branch isolation at the physical level, reducing the risk of backflow and loop interference in the parallel system. It enables parallel access and rapid switching of multiple heat sources without adding multiple sets of circulating pumps, reducing system complexity and construction costs, and facilitating on-site integration and subsequent maintenance and switching. Simultaneously, the valve positions are concentrated on the return water side of each branch, reducing the probability of crossflow during switching and improving the controllability of the switching response.

[0029] In the above embodiment, preferably, the hot water circulation pump 4 is installed on the upper hot water inlet pipe of the hot water storage tank 5. The circulating return water is pressurized by the circulation pump and enters from the upper part of the tank. The secondary side inlet of the water-to-water plate heat exchanger 1 is connected to the lower hot water outlet of the hot water storage tank 5, so that the secondary side of the plate heat exchanger draws water from the relatively low temperature body at the bottom of the tank. The hot water is driven by the hot water circulation pump 4 to enter the secondary side of the water-to-water plate heat exchanger 1 from the lower outlet of the hot water storage tank 5 for heat exchange. After heat exchange, the hot water flows back to the inlet of the hot water circulation pump 4 through the return water pipe and valve position and is sent to the upper inlet of the hot water storage tank 5, thus forming an organization mode of bottom intake and top return of the water tank. This helps to maintain the hot water temperature gradient in the hot water storage tank 5 and reduce the disturbance of the outlet water temperature caused by short-cycle start-up and shutdown or valve switching.

[0030] In this embodiment, the arrangement allows the plate heat exchanger branch to use the water at the bottom of the tank as the inlet on the heated side during heat exchange, which is conducive to forming a more stable temperature difference drive and improving the heat exchange utilization rate of the plate heat exchanger; the return water enters from the top of the tank, which is conducive to maintaining the stratified temperature of the hot water in the tank, reducing the temperature fluctuation caused by the return water disturbance, and improving the temperature stability of the tank.

[0031] In the above embodiments, preferably, the controller is used to implement the strategy of "plate heat exchanger as the main source and air source as the backup source" in the heating season mode: opening the first electric switch valve 6 and closing the second electric switch valve 7 and the third electric switch valve 8, so that the hot water is circulated back to the hot water storage tank 5 after only secondary heat exchange on the water-water plate heat exchanger 1, so as to realize the hot water supply mainly based on the heat exchange on the medium-deep geothermal side.

[0032] When the hot water temperature in the hot water storage tank 5 is detected to be lower than the preset hot water supply temperature threshold, the controller performs valve position switching, closes the first electric switch valve 6 and opens the third electric switch valve 8, so that the hot water is transferred to the air source hot water unit 3 for secondary compensation heating and then flows back to the hot water storage tank 5, realizing the bottoming out of the water supply temperature in the heating season mode.

[0033] In this implementation, the contribution of geothermal heat exchange is prioritized, and the air source branch compensates for insufficient temperature to ensure the continuity of hot water supply and temperature compliance during the heating season. Simultaneously, when geothermal water supply temperature fluctuates or hot water load increases, the backup branch can compensate to prevent the supply water temperature from dropping below the required level.

[0034] In the above embodiments, preferably, the preset hot water supply temperature threshold is 45℃ or 50℃ to match the hot water demand on the hot water side with the water tank heat storage strategy. Furthermore, in the heating season mode, the controller simultaneously determines the temperature based on the geothermal water temperature in the medium-deep geothermal water supply pipeline and the hot water temperature in the hot water storage tank 5: when the geothermal water temperature in the medium-deep geothermal water supply pipeline is less than 50℃, and the hot water temperature in the hot water storage tank 5 is lower than the preset hot water supply temperature threshold, it is determined that the plate heat exchanger branch cannot meet the heating demand, triggering a switching control that closes the first electric switch valve 6 and opens the third electric switch valve 8, allowing the air source water heater unit 3 to undertake the compensating heating task.

[0035] In this implementation, the temperature fluctuation of the geothermal side water supply is incorporated into the mode switching trigger condition, which improves the robustness of temperature control under heating season conditions, reduces the risk of substandard water supply under low temperature conditions, and can reduce unnecessary air source unit intervention time, thus ensuring the priority contribution of the main heat source.

[0036] In the above embodiments, preferably, the medium-deep geothermal tailwater after heat exchange in the water-to-water plate heat exchanger 1 is configured as the heat source input of the heat recovery ground source heat pump unit 2 under heating conditions. This allows the tailwater to continue to participate in the heating process after completing one heat exchange contribution, forming a cascade utilization path of "plate heat exchanger heat exchange - tailwater reuse". This allows the remaining heat of the geothermal tailwater to continue to be recovered on the heat pump side, reducing the heat loss caused by direct discharge of tailwater.

[0037] In this implementation, the depth of geothermal heat utilization and the overall energy efficiency of the system are improved, while the external compensation energy consumption per unit of hot water supply is reduced.

[0038] In the above embodiment, preferably, the controller is used to implement a "heat recovery as the primary source, air source as a backup" strategy in the cooling season mode: opening the second electric switch valve 7 and closing the first electric switch valve 6 and the third electric switch valve 8, so that the hot water is heated by the heat recovery unit 2-1 and then flows back to the hot water storage tank 5. At this time, the heat recovery ground source heat pump unit 2 operates in cooling mode, and the heat recovery unit 2-1 transfers the recoverable heat during the unit's operation to the hot water side, improving the overall energy utilization efficiency during the cooling season.

[0039] When the hot water temperature in the hot water storage tank 5 does not reach the preset hot water supply temperature threshold, the controller switches the valve position, opens the third electric switch valve 8 and closes the other electric switch valves, so that the hot water flows back to the hot water storage tank 5 after being compensated and heated by the air source hot water unit 3, forming a temperature backup path during the cooling season.

[0040] In this implementation, heat from the cooling operation is prioritized for hot water supply, and when heat recovery is insufficient, it is compensated by an air source, thus balancing energy efficiency and water supply compliance.

[0041] In the above embodiment, preferably, the heat recovery ground source heat pump unit 2 includes a heat recovery unit 2-1, a condenser 2-2, and an evaporator 2-3. The heat recovery unit 2-1 is connected to the hot water circulation loop to transfer the heat generated during the operation of the unit to the hot water side to heat the hot water. The evaporator 2-3 is connected to the indoor terminal refrigeration pipeline to undertake the heat exchange on the refrigeration side. The condenser 2-2 is connected to the outdoor buried pipe heat exchanger to realize the heat release and heat exchange to the buried pipe side.

[0042] In this embodiment, the structure enables the unit to form a main cycle of heat absorption on the indoor side and heat release on the buried pipe side during cooling operation. At the same time, the heat recovery unit 2-1 heats the hot water side in parallel, creating a synergistic coupling between cooling and hot water supply. While cooling operation is being carried out, heat is released and recovered to the hot water side, improving the overall energy efficiency of the system and reducing the additional heating burden on the hot water side.

[0043] In the above embodiments, preferably, the controller is used to implement the strategy of "air source as the main source and ground source heat pump as the backup source" in the non-cooling and heating season mode: the third electric switch valve 8 is opened and the first electric switch valve 6 and the second electric switch valve 7 are closed, so that the hot water is heated by the air source hot water unit 3 and then flows back to the hot water storage tank 5, so that the hot water supply is completed on the air source side under the operating conditions of this season.

[0044] When the hot water temperature in the hot water storage tank 5 does not reach the preset hot water supply temperature, the controller switches the valve position, opens the second electric switch valve 7 and closes the other electric switch valves, so that the hot water is transferred to the heat recovery unit 2-1 branch for compensation heating and then flows back to the hot water storage tank 5, realizing the takeover of the backup heating channel.

[0045] In this implementation, the air-source branch reduces system operating costs during non-cooling and heating seasons, while the backup branch intervenes when the temperature deviates from the target, ensuring the stability of the hot water supply. Furthermore, when the ambient temperature is suitable, the high energy efficiency of the air-source water heater unit 3 is utilized to avoid increased operating costs associated with long-term operation of a large system.

[0046] This invention also proposes a method for year-round supply of multi-energy hot water primarily based on deep and shallow geothermal energy, applicable to a year-round supply system of multi-energy hot water primarily based on deep and shallow geothermal energy as disclosed in any of the above embodiments, comprising: First, seasonal operating conditions are obtained and the operating mode is determined. Then, under different modes, a clear hot water circulation path is formed according to the principle of "single valve access and the rest interlocked and closed".

[0047] In the heating season mode, the first electric switch valve 6 is opened and the second electric switch valve 7 and the third electric switch valve 8 are closed, so that the hot water flows back to the hot water storage tank 5 after heat exchange in the water-to-water plate heat exchanger 1; when the hot water temperature in the hot water storage tank 5 is lower than the preset hot water supply temperature threshold, the first electric switch valve 6 is closed and the third electric switch valve 8 is opened, so that the hot water flows back to the hot water storage tank 5 after compensation heating by the air source hot water unit 3. In the cooling season mode, the second electric switch valve 7 is opened and the first electric switch valve 6 and the third electric switch valve 8 are closed, so that the hot water is heated by the heat recovery unit 2-1 and then flows back to the hot water storage tank 5; when the hot water temperature in the hot water storage tank 5 is lower than the preset hot water supply temperature threshold, the second electric switch valve 7 is closed and the third electric switch valve 8 is opened, so that the hot water is compensated and heated by the air source hot water unit 3 and then flows back to the hot water storage tank 5. In the non-cooling and heating season mode, the third electric switch valve 8 is opened and the first electric switch valve 6 and the second electric switch valve 7 are closed, so that the hot water is heated by the air source water heater unit 3 and then flows back to the hot water storage tank 5; when the hot water temperature in the hot water storage tank 5 is lower than the preset hot water supply temperature threshold, the third electric switch valve 8 is closed and the second electric switch valve 7 is opened, so that the hot water is compensated and heated by the heat recovery unit 2-1 and then flows back to the hot water storage tank 5.

[0048] In this implementation, the automatic switching and temperature backup of hot water supply throughout the year are achieved by using a seasonal mode as the main line. During the heating season, the main heat exchange is medium-deep geothermal heat exchange; during the cooling season, the main heat recovery is ground source heat pump; and during the non-cooling and heating season, the main heat exchange is air source water heater 3. In each mode, a backup branch is configured for compensatory heating, which reduces the frequency of manual intervention and improves the stability of water supply and overall energy efficiency. This achieves the overall goal of reasonable selection, reducing energy waste, improving energy efficiency, and reducing operation and management costs.

[0049] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A multi-energy year-round hot water supply system primarily utilizing deep and shallow geothermal energy, characterized in that, It includes a hot water storage tank, a hot water circulation pump, a water-to-water plate heat exchanger, a heat recovery ground source heat pump unit, an air source hot water unit, a first electric switch valve, a second electric switch valve, a third electric switch valve, and a controller. The primary side of the water-to-water plate heat exchanger is connected to the medium-deep geothermal water supply pipeline and the medium-deep geothermal tailwater pipeline. The outlet of the hot water storage tank is connected to the secondary inlet of the water-to-water plate heat exchanger, the heat recovery inlet of the heat recovery ground source heat pump unit, and the inlet of the air source hot water unit via distribution pipelines. The secondary outlet of the water-to-water plate heat exchanger is connected to the inlet of the hot water circulation pump via the first electric switch valve; the outlet of the heat recovery unit is connected to the inlet of the hot water circulation pump via the second electric switch valve; the outlet of the air source hot water unit is connected to the inlet of the hot water circulation pump via the third electric switch valve; and the outlet of the hot water circulation pump is connected to the inlet of the hot water storage tank. The controller is connected to the first electric switch valve, the second electric switch valve and the third electric switch valve, and is used to determine the operating mode according to seasonal operating condition information, and in the operating mode, open one of the first electric switch valve, the second electric switch valve or the third electric switch valve and close the other electric switch valves, so that hot water circulates through the target branch for heat exchange / heating and flows back to the hot water storage tank. The controller is also used to switch the operating mode to enable the backup branch to compensate for the heating of hot water when the hot water temperature in the hot water storage tank does not reach the preset hot water supply temperature threshold.

2. The multi-energy year-round hot water supply system based primarily on deep and shallow geothermal energy as described in claim 1, characterized in that, The outlet of the hot water storage tank is connected to the secondary inlet of the water-to-water plate heat exchanger, the inlet of the heat recovery unit, and the inlet of the air source hot water unit via distribution pipelines. The secondary outlet of the water-to-water plate heat exchanger is connected to the inlet of the hot water circulation pump via the first electric switch valve; the outlet of the heat recovery unit is connected to the inlet of the hot water circulation pump via the second electric switch valve; and the outlet of the air source hot water unit is connected to the inlet of the hot water circulation pump via the third electric switch valve. The outlet of the hot water circulation pump is connected to the inlet of the hot water storage tank.

3. The multi-energy year-round hot water supply system based primarily on deep and shallow geothermal energy according to claim 1 or 2, characterized in that, The hot water circulation pump is installed on the upper hot water inlet pipe of the hot water storage tank, and the secondary inlet of the water-to-water plate heat exchanger is connected to the lower hot water outlet of the hot water storage tank.

4. The multi-energy year-round hot water supply system based primarily on deep and shallow geothermal energy according to claim 1, characterized in that, The controller is used to open the first electric switch valve and close the second electric switch valve and the third electric switch valve in the heating season mode, so that the hot water flows back to the hot water storage tank after heat exchange on the secondary side of the water-water plate heat exchanger. Furthermore, when the temperature of the hot water in the hot water storage tank is lower than the preset hot water supply temperature threshold, the controller controls the first electric switch valve to close and the third electric switch valve to open, so that the hot water is returned to the hot water storage tank after being compensated and heated by the air source hot water unit.

5. The multi-energy year-round hot water supply system based primarily on deep and shallow geothermal energy according to claim 4, characterized in that, The preset hot water supply temperature threshold is 45℃ or 50℃; and, in the heating season mode, when the geothermal water temperature in the medium-deep geothermal water supply pipeline is less than 50℃ and the hot water temperature in the hot water storage tank is lower than the preset hot water supply temperature threshold, the controller performs a switching control to close the first electric switch valve and open the third electric switch valve.

6. The multi-energy year-round hot water supply system based primarily on deep and shallow geothermal energy according to claim 4 or 5, characterized in that, The medium-deep geothermal tailwater after heat exchange in the water-to-water plate heat exchanger is configured as the heat source input for the heat recovery ground source heat pump unit under heating conditions.

7. The multi-energy year-round hot water supply system based primarily on deep and shallow geothermal energy according to claim 1, characterized in that, The controller is used to open the second electric switch valve and close the first electric switch valve and the third electric switch valve in the cooling season mode, so that the hot water is heated by the heat recovery unit and then flows back to the hot water storage tank. When the hot water temperature in the hot water storage tank does not reach the preset hot water supply temperature threshold, the third electric switch valve is switched on and the other electric switch valves are closed, so that the hot water is returned to the hot water storage tank after being compensated and heated by the air source hot water unit.

8. The multi-energy year-round hot water supply system based primarily on deep and shallow geothermal energy according to claim 1, characterized in that, The heat recovery ground source heat pump unit includes a heat recovery unit, a condenser, and an evaporator. The heat recovery unit is connected to a hot water circulation loop to heat hot water. The evaporator is connected to an indoor terminal refrigeration pipeline. The condenser is connected to an outdoor buried pipe heat exchanger.

9. The multi-energy year-round hot water supply system based primarily on deep and shallow geothermal energy according to claim 1, characterized in that, The controller is used to open the third electric switch valve and close the first electric switch valve and the second electric switch valve in the non-cooling and heating season mode, so that the hot water is heated by the air source water heater and then flows back to the hot water storage tank. When the hot water temperature in the hot water storage tank does not reach the preset hot water supply temperature, the second electric switch valve is switched on and the other electric switch valves are closed, so that the hot water is returned to the hot water storage tank after being compensated and heated by the heat recovery unit.

10. A method for year-round supply of multi-energy hot water, primarily utilizing deep and shallow geothermal energy, characterized in that... The multi-energy year-round hot water supply system, primarily based on deep and shallow geothermal energy, as described in any one of claims 1 to 9, comprises: Obtain seasonal operating condition information and determine the operating mode; In the heating season mode, the first electric switch valve is opened and the second and third electric switch valves are closed, so that the hot water flows back to the hot water storage tank after heat exchange through the water-to-water plate heat exchanger; when the hot water temperature in the hot water storage tank is lower than the preset hot water supply temperature threshold, the first electric switch valve is closed and the third electric switch valve is opened, so that the hot water flows back to the hot water storage tank after being compensated and heated by the air source hot water unit. In the cooling season mode, the second electric switch valve is opened and the first electric switch valve and the third electric switch valve are closed, so that the hot water is heated by the heat recovery unit and then flows back to the hot water storage tank; when the hot water temperature in the hot water storage tank is lower than the preset hot water supply temperature threshold, the second electric switch valve is closed and the third electric switch valve is opened, so that the hot water is compensated and heated by the air source hot water unit and then flows back to the hot water storage tank. In non-cooling and heating season mode, the third electric switch valve is opened and the first and second electric switch valves are closed, so that the hot water is heated by the air source water heater and then flows back to the hot water storage tank; when the hot water temperature in the hot water storage tank is lower than the preset hot water supply temperature threshold, the third electric switch valve is closed and the second electric switch valve is opened, so that the hot water is compensated and heated by the heat recovery unit and then flows back to the hot water storage tank.

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