Modularized direct type phase change energy storage device and control method thereof

Abstract

The invention relates to a modularized direct type phase change energy storage device and a control method thereof, and belongs to the technical field of energy conservation of air conditioning systems. The device comprises a modularized box body, a phase change energy storage unit, an electric valve group, a circulating water pump and an intelligent electric control system. Tradition is broken through, a plate heat exchanger is omitted, and the phase change unit and the air conditioner water system are directly connected and safely isolated through valve control. The device has a direct energy storage mode and an independent energy supply mode. According to the direct energy storage mode, large-system water flow directly flows through the phase change unit to conduct efficient energy storage and adjust the load of a main machine. The latter can be separated from a large system, and the stored energy is used for independently supplying energy to the tail end. Through filtering, corrosion-resistant materials and a soft switching control strategy, the problems of water quality and water hammer caused by direct connection are solved, the structure is simplified, the energy efficiency is improved, operation is reliable, and the contradiction between low load energy efficiency of the central air conditioner and flexible energy supply of the tail end is effectively overcome.

Description

Technical Field

[0001] This invention relates to the field of building energy conservation and HVAC technology, specifically to a modular direct phase change energy storage device and its control method. Background Technology

[0002] Central air conditioning systems account for a significant portion of energy consumption in large public buildings, and they face two prominent problems in actual operation. First, the system load fluctuates greatly with usage demand, and the energy efficiency of the main unit drops sharply under low load conditions, resulting in energy waste. Second, when cooling or heating is required separately in certain periods or areas, the entire central air conditioning system often still needs to be started, leading to an extremely low-efficiency operation of "overpowered systems."

[0003] While phase change materials (PCMs) have been used for energy storage in existing technologies, they often have significant limitations. Large-scale system-level energy storage devices require high initial investment and occupy a large space, making it difficult to meet the needs of flexible, distributed end-user applications. For end-user energy storage solutions, due to concerns about the impact on water quality in the main air conditioning system, plate heat exchangers are commonly used to isolate the energy storage unit from the main system. While this indirect heat exchange method improves safety, it inevitably introduces heat exchange temperature difference losses, reduces energy transfer efficiency, and increases system complexity and cost.

[0004] Therefore, a prominent contradiction exists in current technologies: while achieving efficient and flexible energy storage and supply at the end point, they are constrained by the efficiency losses and structural complexity brought about by indirect heat exchange architectures. There is an urgent need for an innovative solution that can overcome this technological bias and achieve safe, efficient, and direct coupling and decoupling between energy storage units and air conditioning water systems. Summary of the Invention

[0005] In view of the above-mentioned technical problems in related technologies, the present invention proposes a modular direct phase change energy storage device and its control method, which can overcome the above-mentioned shortcomings of the prior art.

[0006] To achieve the above-mentioned technical objectives, the technical solution of the present invention is implemented as follows: A modular direct phase change energy storage device; This modular direct phase change energy storage device includes: Modular enclosure; A phase change energy storage unit is installed inside the modular housing, which is filled with phase change material and has channels for fluid flow. The piping connection system, which is housed within the modular enclosure, includes a large system interface for connecting to the central air conditioning main water system and a terminal interface for connecting to the air conditioning terminals. An electric valve assembly, which is installed on the pipeline connection system, includes a first electric valve and a second electric valve for controlling the on / off state of the large system interface, and a third electric valve and a fourth electric valve for controlling the on / off state of the end interface. A circulating water pump is installed on the pipeline inside the modular housing; An intelligent electronic control system, which is communicatively connected to the circulating water pump and the electric valve assembly, is configured to control the opening and closing states of the electric valve assembly and the start and stop of the circulating water pump, so that the device can switch between the following two operating modes: Direct energy storage mode: The first electric valve and the second electric valve are open, the third electric valve and the fourth electric valve are closed, the circulating water pump is stopped, and the water from the central air conditioning main water system flows directly through the channel of the phase change energy storage unit through the large system interface for heat exchange. Independent power supply mode: The first electric valve and the second electric valve are closed, the third electric valve and the fourth electric valve are open, the circulating water pump is started, and the medium inside the drive device circulates between the phase change energy storage unit and the air conditioning terminal connected to the terminal interface.

[0007] Furthermore, on the pipeline between the large system interface and the phase change energy storage unit, a filter for filtering water from the central air conditioning main water system is installed after the first electric valve and before the phase change energy storage unit.

[0008] Furthermore, the heat exchange surface in the phase change energy storage unit that comes into contact with the fluid is made of a corrosion-resistant metal material.

[0009] Furthermore, the phase change material is a hydrated salt composite material with a phase change temperature between 5°C and 12°C, or an organic phase change material with a phase change temperature between 40°C and 60°C.

[0010] Furthermore, when the phase change material is an organic phase change material, the phase change energy storage unit is also provided with a thermally enhanced structure, which includes one or more of metal fins, porous metal foam, or high thermal conductivity fillers.

[0011] Furthermore, each electric valve in the electric valve group is a slow-opening and slow-closing type electric valve, and its full-stroke opening and closing time is not less than 15 seconds.

[0012] Furthermore, the circulating water pump is a variable frequency water pump.

[0013] Furthermore, the mode switching control logic of the intelligent electronic control system includes: When switching from direct energy storage mode to independent energy supply mode, first control the circulating water pump to start or run at low speed, then open the third electric valve and the fourth electric valve, and then close the first electric valve and the second electric valve. When switching from independent power supply mode to direct energy storage mode, the circulating water pump is first controlled to slow down, then the first electric valve and the second electric valve are opened, and then the circulating water pump is stopped and the third electric valve and the fourth electric valve are closed.

[0014] According to another aspect of the present invention, a control method for a modular direct phase change energy storage device is provided; The control method for this modular direct phase change energy storage device includes: Direct energy storage mode control steps: control the first electric valve and the second electric valve to open, control the third electric valve and the fourth electric valve to close, and control the circulating water pump to stop, so that the water flow of the central air conditioning main water system flows directly through the phase change energy storage unit; Independent power supply mode control steps: control the first electric valve and the second electric valve to close, control the third electric valve and the fourth electric valve to open, and control the circulating water pump to start, so that the medium inside the device circulates independently between the phase change energy storage unit and the air conditioning terminal.

[0015] The beneficial effects of this invention are as follows: By adopting a direct connection architecture controlled by valve groups, the traditionally necessary plate heat exchanger is eliminated, thereby simplifying the system structure and avoiding heat exchange temperature difference losses; by integrating water filtration and corrosion-resistant design for synergistic protection, as well as a time-based soft switching control strategy, the risks of water quality and hydraulic shock caused by direct connection are effectively addressed, thereby achieving a balance between safe and reliable device operation, improved main unit energy efficiency, and flexible on-demand energy supply at the terminal, providing an effective solution to the contradiction between low efficiency under low load and local energy demand in central air conditioning systems. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a front view of a modular direct phase change energy storage device according to an embodiment of the present invention; Figure 2 This is a perspective view of a modular direct phase change energy storage device according to an embodiment of the present invention; Figure 3This is a system architecture diagram of a modular direct phase change energy storage device according to an embodiment of the present invention; In the diagram: 1. Modular enclosure; 2. Intelligent control cabinet; 3. Phase change energy storage unit; 4. First electric valve; 5. Second electric valve; 6. Third electric valve; 7. Fourth electric valve; 8. Circulating water pump; 9. Filter. Detailed Implementation

[0018] 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, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0019] like Figures 1 to 3 As shown, a modular direct phase change energy storage device according to an embodiment of the present invention includes: Modular enclosure; A phase change energy storage unit is installed inside the modular housing, which is filled with phase change material and has channels for fluid flow. The piping connection system, which is housed within the modular enclosure, includes a large system interface for connecting to the central air conditioning main water system and a terminal interface for connecting to the air conditioning terminals. An electric valve assembly, which is installed on the pipeline connection system, includes a first electric valve and a second electric valve for controlling the on / off state of the large system interface, and a third electric valve and a fourth electric valve for controlling the on / off state of the end interface. A circulating water pump is installed on the pipeline inside the modular housing; An intelligent electronic control system, which is communicatively connected to the circulating water pump and the electric valve assembly, is configured to control the opening and closing states of the electric valve assembly and the start and stop of the circulating water pump, so that the device can switch between the following two operating modes: Direct energy storage mode: The first electric valve and the second electric valve are open, the third electric valve and the fourth electric valve are closed, the circulating water pump is stopped, and the water from the central air conditioning main water system flows directly through the channel of the phase change energy storage unit through the large system interface for heat exchange. Independent power supply mode: The first electric valve and the second electric valve are closed, the third electric valve and the fourth electric valve are open, the circulating water pump is started, and the medium inside the drive device circulates between the phase change energy storage unit and the air conditioning terminal connected to the terminal interface.

[0020] According to an embodiment of the present invention, a modular direct phase change energy storage device is provided, in a specific embodiment, on the pipeline between the large system interface and the phase change energy storage unit, after the first electric valve and before the phase change energy storage unit, a filter for filtering water quality from the central air conditioning main water system is provided.

[0021] According to an embodiment of the present invention, in a specific implementation of a modular direct phase change energy storage device, the heat exchange surface in the phase change energy storage unit that is in contact with the fluid is made of a corrosion-resistant metal material.

[0022] According to an embodiment of the present invention, in a specific embodiment of a modular direct phase change energy storage device, the phase change material is a hydrated salt composite material with a phase change temperature between 5°C and 12°C, or an organic phase change material with a phase change temperature between 40°C and 60°C.

[0023] According to an embodiment of the present invention, a modular direct phase change energy storage device is provided. In a specific embodiment, when the phase change material is an organic phase change material, the phase change energy storage unit is further provided with a thermal conductivity enhancement structure. The thermal conductivity enhancement structure includes one or more of metal fins, porous metal foam, or high thermal conductivity fillers.

[0024] According to an embodiment of the present invention, in a certain specific implementation of a modular direct phase change energy storage device, each electric valve in the electric valve group is a slow-opening and slow-closing type electric valve, and its full-stroke opening and closing time is not less than 15 seconds.

[0025] According to an embodiment of the present invention, in a specific implementation of a modular direct phase change energy storage device, the circulating water pump is a variable frequency water pump.

[0026] According to an embodiment of the present invention, a modular direct phase change energy storage device, in a specific implementation, includes the mode switching control logic of the intelligent electronic control system comprising: When switching from direct energy storage mode to independent energy supply mode, first control the circulating water pump to start or run at low speed, then open the third electric valve and the fourth electric valve, and then close the first electric valve and the second electric valve. When switching from independent power supply mode to direct energy storage mode, the circulating water pump is first controlled to slow down, then the first electric valve and the second electric valve are opened, and then the circulating water pump is stopped and the third electric valve and the fourth electric valve are closed.

[0027] A control method for a modular direct phase change energy storage device according to an embodiment of the present invention includes: Direct energy storage mode control steps: control the first electric valve and the second electric valve to open, control the third electric valve and the fourth electric valve to close, and control the circulating water pump to stop, so that the water flow of the central air conditioning main water system flows directly through the phase change energy storage unit; Independent power supply mode control steps: control the first electric valve and the second electric valve to close, control the third electric valve and the fourth electric valve to open, and control the circulating water pump to start, so that the medium inside the device circulates independently between the phase change energy storage unit and the air conditioning terminal.

[0028] To facilitate understanding of the above technical solutions of the present invention, the following detailed description of the above technical solutions of the present invention will be provided through specific usage methods.

[0029] In practical application, the core of the modular direct phase change energy storage device according to the present invention lies in its systematic design concept of direct connection, intelligent protection, and smooth switching. This device, as a standardized module, is directly connected in parallel to the air conditioning water system via a valve assembly, rather than being indirectly connected via a plate heat exchanger.

[0030] Its core working mode includes: 1. Direct Energy Storage Mode: When the central air conditioning system is running, the intelligent electronic control system controls the valves to direct the system's chilled or hot water directly through the phase change energy storage unit within the device for heat exchange. This process not only cools or heats the phase change material but also acts as an adjustable load, actively maintaining the main unit load within the high-efficiency range of 40%-90%.

[0031] 2. Independent power supply mode: When the main system shuts down or requires local power supply, the intelligent electrical control system switches valves, disconnects from the main system, and starts the built-in circulating water pump, so that the device can use the stored cold / heat to form an independent circulation system to supply power to specific terminal equipment.

[0032] To ensure the feasibility of the direct connection solution, this invention integrates the following key innovations: Water quality protection system: Through the synergistic effect of the filter installed at the water inlet and the corrosion-resistant material used in the phase change energy storage unit, the system effectively addresses the risks of scaling and corrosion that may arise from the water quality of the large system.

[0033] Phase change material selection and enhancement: For cold storage and heat storage needs, modified hydrated salts and organic phase change materials are selected respectively, and the latter is designed with thermal conductivity enhancement to ensure high heat exchange efficiency.

[0034] Shock-free switching control: By adopting slow-opening and slow-closing electric valves, variable frequency water pumps, and specific timing control logic, the switching process between the two working modes is ensured to be absolutely smooth, completely eliminating water hammer.

[0035] The present invention will now be described in detail with reference to the embodiments.

[0036] The modular housing of this invention integrates a phase change energy storage unit, a circulating water pump, an electric valve assembly (V1-V4), a filter, and an intelligent electronic control system. The housing is equipped with a main system interface (A / B) and a terminal interface (C / D).

[0037] Example: Office fan coil unit application Scenario 1: High-efficiency daytime cooling The intelligent electronic control system detects a low load rate for the main unit (e.g., 35%) and activates the direct energy storage mode to improve energy efficiency. The system controls V1 and V2 to open, V3 and V4 to close, and the water pumps to stop. Chilled water from the main system at 7°C flows through interface A, the filter, and valve V1 into the phase change energy storage unit (filled with modified hydrated salt with a phase change temperature of 8°C). After being cooled, the water returns to the main system via V2 and interface B. This process adds a controllable cooling load to the system, raising the main unit load to the high-efficiency zone. During this process, the filter intercepts impurities, and the corrosion-resistant phase change unit casing resists the influence of water quality.

[0038] Scenario 2: Independent cooling at night After the main system is shut down, employees turn on the fan coil units. The intelligent electronic control system executes an anti-impact switching procedure: first, the variable frequency water pump is started at low speed; then V3 and V4 are slowly turned on; next, V1 and V2 are slowly turned off; finally, the water pump is adjusted to its operating speed. The unit enters an independent power supply mode, where the built-in water pump drives the medium to circulate between the phase change unit and the fan coil units, using the cooling capacity of the phase change material to cool the room without needing to start the main system.

[0039] In summary, by employing the above-mentioned technical solution of this invention, a direct connection architecture controlled by valve groups is adopted, eliminating the need for traditional plate heat exchangers, thereby simplifying the system structure and avoiding heat exchange temperature difference losses. Through the synergistic protection of integrated water filtration and corrosion-resistant design, as well as a time-based soft switching control strategy, the risks of water quality and hydraulic shock caused by direct connection are effectively addressed. This achieves a balance between safe and reliable device operation, improved main unit energy efficiency, and flexible on-demand energy supply at the terminal, providing an effective solution to the contradiction between low efficiency under low load and local energy demand in central air conditioning systems.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A modular direct phase change energy storage device, characterized in that, include: Modular enclosure; A phase change energy storage unit is installed inside the modular housing, which is filled with phase change material and has channels for fluid flow. The piping connection system, which is housed within the modular enclosure, includes a large system interface for connecting to the central air conditioning main water system and a terminal interface for connecting to the air conditioning terminals. An electric valve assembly, which is installed on the pipeline connection system, includes a first electric valve and a second electric valve for controlling the on / off state of the large system interface, and a third electric valve and a fourth electric valve for controlling the on / off state of the end interface. A circulating water pump is installed on the pipeline inside the modular housing; An intelligent electronic control system, which is communicatively connected to the circulating water pump and the electric valve assembly, is configured to control the opening and closing states of the electric valve assembly and the start and stop of the circulating water pump, so that the device can switch between the following two operating modes: Direct energy storage mode: The first electric valve and the second electric valve are open, the third electric valve and the fourth electric valve are closed, the circulating water pump is stopped, and the water from the central air conditioning main water system flows directly through the channel of the phase change energy storage unit through the large system interface for heat exchange. Independent power supply mode: The first electric valve and the second electric valve are closed, the third electric valve and the fourth electric valve are open, the circulating water pump is started, and the medium inside the drive device circulates between the phase change energy storage unit and the air conditioning terminal connected to the terminal interface.

2. The modular direct phase change energy storage device according to claim 1, characterized in that, On the pipeline between the large system interface and the phase change energy storage unit, after the first electric valve and before the phase change energy storage unit, a filter is installed to filter the water quality from the central air conditioning main water system.

3. The modular direct phase change energy storage device according to claim 1, characterized in that, The heat exchange surfaces in the phase change energy storage unit that come into contact with the fluid are made of corrosion-resistant metal.

4. A modular direct phase change energy storage device according to claim 1, characterized in that, The phase change material is a hydrated salt composite material with a phase change temperature between 5°C and 12°C, or an organic phase change material with a phase change temperature between 40°C and 60°C.

5. A modular direct phase change energy storage device according to claim 4, characterized in that, When the phase change material is an organic phase change material, the phase change energy storage unit is further provided with a thermally enhanced structure, which includes one or more of metal fins, porous metal foam, or high thermal conductivity fillers.

6. A modular direct phase change energy storage device according to claim 1, characterized in that, Each electric valve in the electric valve group is a slow-opening and slow-closing type electric valve, and its full-stroke opening and closing time is not less than 15 seconds.

7. A modular direct phase change energy storage device according to claim 1, characterized in that, The circulating water pump is a variable frequency pump.

8. A modular direct phase change energy storage device according to claim 1, characterized in that, The mode switching control logic of the intelligent electronic control system includes: When switching from direct energy storage mode to independent energy supply mode, first control the circulating water pump to start or run at low speed, then open the third electric valve and the fourth electric valve, and then close the first electric valve and the second electric valve. When switching from independent power supply mode to direct energy storage mode, the circulating water pump is first controlled to slow down, then the first electric valve and the second electric valve are opened, and then the circulating water pump is stopped and the third electric valve and the fourth electric valve are closed.

9. A control method for a modular direct phase change energy storage device according to any one of claims 1 to 8, characterized in that, include: Direct energy storage mode control steps: control the first electric valve and the second electric valve to open, control the third electric valve and the fourth electric valve to close, and control the circulating water pump to stop, so that the water flow of the central air conditioning main water system flows directly through the phase change energy storage unit; Independent power supply mode control steps: control the first electric valve and the second electric valve to close, control the third electric valve and the fourth electric valve to open, and control the circulating water pump to start, so that the medium inside the device circulates independently between the phase change energy storage unit and the air conditioning terminal.

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