Greenhouse Structure and Photosynthesis Optimization Integrated Control System for Land-Based Porphyra Aquaculture

Abstract

The present invention relates to a greenhouse-based integrated environmental control system for land-based cultivation of seaweed and a control method thereof. A system according to the present invention comprises a greenhouse structure including a transparent outer shell and a refrigerator, a land-based aquaculture tank disposed inside the greenhouse structure, a flow velocity forming means and a heat pump within the land-based aquaculture tank, an environmental sensor unit, and a control unit that controls the environmental control means including the refrigerator and the heat pump in conjunction based on the measurement value of the environmental sensor unit. According to the present invention, by controlling the greenhouse air temperature by a refrigerator (maintaining 22°C or lower) and controlling the water tank temperature by a heat pump (maintaining 10°C to 18°C), an optimal growth environment can be maintained year-round, thereby providing the effect of shortening the growth period of seaweed and improving productivity.

Description

Technology Field

[0001] The present invention relates to the field of land-based aquaculture technology for seaweed, and more specifically, to a land-based aquaculture system and a control method thereof, wherein a land-based aquaculture tank is placed within a greenhouse structure composed of a transparent outer shell, and the greenhouse environment and the tank environment are controlled in conjunction through an integrated control unit, including greenhouse air temperature control by a chiller and tank water temperature control by a heat pump, thereby maintaining the light, thermal, and water environments necessary for the growth of seaweed in an optimal state year-round. Background Technology

[0002] Seaweed, including laver (Porphyra spp.), is a fishery product of high economic value worldwide and is farmed on a large scale in countries such as Korea, Japan, and China. Conventional seaweed farming has mainly relied on offshore stake or floating farming methods, but there have been problems with high variability in production volume and difficulty in quality control due to rising sea temperatures caused by climate change, increased frequency of red tides, and natural disasters such as typhoons.

[0003] Although land-based aquaculture technology has been researched to overcome the limitations of such marine aquaculture, conventional land-based seaweed aquaculture technology had the following limitations.

[0004] First, conventional land-based aquaculture systems mostly rely on indoor tanks or simple shading facilities, which resulted in high electricity costs due to artificial lighting and problems such as reduced photosynthetic efficiency due to the difficulty in utilizing natural light.

[0005] Second, major growth factors such as light intensity, air temperature, water temperature, dissolved oxygen (DO), and flow rate were managed individually, making integrated control that considers the interactions between environmental variables impossible.

[0006] Third, year-round aquaculture was difficult due to the absence of active temperature control measures to maintain water temperatures within an appropriate range in high-temperature summer environments and low-temperature winter environments.

[0007] Fourth, the distribution of flow velocity inside the tank was uneven, so the DO supply amount and water temperature varied depending on the location of the seaweed cultivation, resulting in variations in growth even within the same tank. Prior art literature

[0008] Registered Patent No. 10-2740262 The problem to be solved

[0009] The present invention has been devised to solve the problems of the aforementioned prior art and aims to solve the following technical problems.

[0010] First, the purpose is to optimize the light environment by stably supplying natural light in the form of diffused light through a greenhouse structure utilizing a transparent outer shell.

[0011] Second, the purpose is to maintain an optimal thermal environment year-round through greenhouse air temperature control by a chiller and water tank temperature control by a heat pump.

[0012] Third, the purpose is to realize optimal control that considers the interaction between environmental variables by integrating and managing the greenhouse and water tank environments within a single control system.

[0013] Fourth, the purpose is to ensure uniformity of DO and water temperature within the tank through a multi-path flow velocity structure. means of solving the problem

[0014] According to one aspect of the present invention for solving the above problem, a greenhouse-based control system for land-based cultivation of seaweed is provided.

[0015] The above system comprises: a greenhouse structure including a transparent outer shell and a chiller for cooling the air inside the greenhouse; a land-based aquaculture tank disposed inside the greenhouse structure; a flow rate forming means for controlling the water environment within the land-based aquaculture tank and a heat pump for heating or cooling the water temperature; an environmental sensor unit for measuring at least two of light intensity, water temperature, and dissolved oxygen (DO); and a control unit for controlling the environmental control means of the greenhouse structure, the flow rate forming means, the chiller, and the heat pump in conjunction based on the measured values ​​of the environmental sensor unit.

[0016] The above control unit controls at least two of the light environment, thermal environment, and water environment in combination according to changes in the environment inside the greenhouse.

[0017] According to another aspect of the present invention, an environmental control method for cultivating seaweed in a land-based aquaculture tank placed within a greenhouse structure is provided.

[0018] The above method comprises: (a) a step of measuring at least two of light intensity, water temperature, dissolved oxygen (DO), flow rate, and air temperature through an environmental sensor unit; (b) a step of determining an environmental change based on the measured values; and (c) a step of controlling at least one of an environmental control means of a greenhouse structure, a chiller, a heat pump, and a flow rate forming means of a land-based aquaculture tank according to the determination result. Effects of the invention

[0019] The greenhouse-based environmental integrated control system for land-based seaweed aquaculture and the control method according to the present invention provide the following effects.

[0020] First, greenhouse structures based on transparent envelopes transmit natural light into the interior in the form of diffuse light, mitigating abrupt fluctuations in photosynthetic photon flux density (PPFD) and improving the stability of the light environment.

[0021] Second, by controlling greenhouse air temperature with a chiller and water tank temperature with a heat pump, optimal growth temperatures can be maintained even in high-temperature summer and low-temperature winter environments, making year-round aquaculture possible.

[0022] Third, through the integrated control of the greenhouse and water tank environments, optimal control considering the interaction between environmental variables is possible.

[0023] Fourth, the multi-path flow velocity structure minimizes interlayer deviations in DO and water temperature inside the tank, thereby improving growth uniformity.

[0024] Fifth, productivity is improved by shortening the growth period of seaweed through the minimization of photosynthetic stress, homogenization of DO and water temperature, and environmentally linked control technology. Brief explanation of the drawing

[0025] FIG. 1 is a block diagram showing the overall configuration of a greenhouse-based seaweed land-based aquaculture system according to one embodiment of the present invention. FIG. 2 is a side cross-sectional view showing the arrangement of the main components and control elements of a greenhouse structure according to one embodiment of the present invention. FIG. 3 is a cross-sectional view showing a multi-path flow velocity structure inside a land-based aquaculture tank according to one embodiment of the present invention. FIG. 4 is a schematic diagram showing the interlocking structure of a lifting device, an environment sensor unit, and an integrated control unit according to one embodiment of the present invention. FIG. 5 is a flowchart showing the control flow of an integrated control unit according to one embodiment of the present invention. FIG. 6 is a table showing the operating mode for each growth stage according to one embodiment of the present invention. Specific details for implementing the invention

[0026] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. The advantages and features of the present invention, and the methods for achieving them, will become clear by referring to the embodiments described below in detail together with the attached drawings. However, the present invention is not limited to the embodiments disclosed below but can be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims.

[0027] Referring to FIG. 1, a seaweed land-based aquaculture system (1) according to one embodiment of the present invention includes a greenhouse structure (10), a land-based aquaculture tank (20), a seaweed cultivator (30), a control unit (40), an environment sensor unit (50), and an external environment collection module (60).

[0028] The greenhouse structure (10) includes a transparent outer shell (11), a skylight (12), a skylight drive motor (13), a light-blocking screen (14), a thermal insulation screen (15), a light-blocking screen drive motor (16), a thermal insulation screen drive motor (17), and a refrigerator (18).

[0029] The land-based aquaculture tank (20) includes a mesh structure (21), an inlet (22), a return port (23), a bottom upward flow nozzle (24), a circulation pump (25), a ring blower (26), and a heat pump (27).

[0030] Referring to FIG. 2, the greenhouse structure (10) includes a transparent outer shell (11), a skylight (12), a skylight drive motor (13), a light-blocking screen (14), a thermal insulation screen (15), a light-blocking screen drive motor (16), a thermal insulation screen drive motor (17), and a refrigerator (18).

[0031] The transparent outer shell (11) can be formed from at least one of a polymethyl methacrylate (PMMA) panel, a polycarbonate (PC) panel, glass, a polyethylene terephthalate (PET) film, a polyethylene (PE) film, and an ethylene-tetrafluoroethylene (ETFE) film, and forms the roof and outer wall of the greenhouse.

[0032] The above-mentioned transparent outer shell (11) transmits natural light into the interior in the form of diffused light, thereby performing the function of mitigating the rapid fluctuations in PPFD received by the seaweed plant (30).

[0033] The refrigerator (18) is a device for actively controlling the air temperature inside the greenhouse structure (10), and cools the air inside the greenhouse in a high-temperature environment during the summer to maintain a temperature environment suitable for the growth of seaweed.

[0034] In this embodiment, the refrigerator (18) is automatically controlled by the control unit (40) based on the measurement value of the air temperature sensor (46) and is operated according to the following conditions:

[0035] Cooling operation when the air temperature inside the greenhouse exceeds the set upper limit (e.g., 22℃)

[0036] Preemptive cooling operation when high temperatures are expected in ambient temperature forecasts

[0037] The skylight (12) is an openable structure formed at the top of the roof of the greenhouse structure (10) and is opened or closed by a skylight drive motor (13). The skylight (12) performs the function of preventing overheating and excessive humidity inside the greenhouse and maintaining the CO₂ concentration at an appropriate level through ventilation with the outside air.

[0038] The opening and closing of the skylight (12) is controlled according to the following conditions:

[0039] Open if the air temperature inside the greenhouse exceeds the set upper limit (e.g., 22℃).

[0040] Open when the relative humidity inside the greenhouse exceeds the set value

[0041] Closed when the outside temperature is below the set lower limit and the inside temperature is within the appropriate range.

[0042] The light-blocking screen (14) is installed at the bottom of the light-transmitting outer shell (11) and is deployed or retracted by a light-blocking screen drive motor (16). The light-blocking screen (14) performs the function of blocking excessive sunlight to prevent light saturation and light inhibition of the seaweed (30) and suppressing the rise in water temperature within the tank.

[0043] The thermal insulation screen (15) is installed as a separate layer below the shading screen (14) and is deployed or retracted by the thermal insulation screen drive motor (17). The thermal insulation screen (15) performs the function of preventing radiant heat loss inside the greenhouse at night or during cold weather, and suppressing a drop in water temperature inside the water tank.

[0044] Referring to FIG. 3, the land-based aquaculture tank (20) is installed inside the greenhouse structure (10) and is equipped with a multi-path flow structure including a mesh structure (21), an inlet (22), a return port (23), a bottom upward flow nozzle (24), a circulation pump (25), a ring blower (26), and a heat pump (27).

[0045] The heat pump (27) is a device for actively controlling the water temperature of the land-based aquaculture tank (20), and heats or cools the temperature of the seawater in the tank through a seawater heat exchanger.

[0046] In this embodiment, the heat pump (27) is automatically controlled by the control unit (40) based on the measurement value of the water temperature sensor (44) and is operated according to the following conditions:

[0047] Cooling operation when water temperature exceeds the set upper limit (e.g., 18℃)

[0048] Heating operation when water temperature is below the set lower limit (e.g., 10℃)

[0049] Preemptive heating / cooling operation based on ambient temperature forecast information

[0050] The inlet (22) is installed at the lower part of one side wall of the water tank (20) to supply filtered seawater from the outside in a horizontal direction. The return port (23) is installed at the upper part of the other side wall of the water tank (20) to stabilize the surface water velocity by discharging the upper layer water.

[0051] The bottom upward flow nozzle (24) is arranged on the bottom of the water tank (20) and sprays air supplied from the ring blower (26) upward in the form of microbubbles.

[0052] By the combination of the inlet (22), the return port (23), and the bottom upward flow nozzle (24), a multi-path flow velocity structure is created inside the water tank (20) in which horizontal flow, upward flow, and surface return flow are simultaneously formed, thereby minimizing the interlayer deviation of DO and water temperature.

[0053] Referring to FIG. 4, the seaweed seedlings (30) are contained within a land-based aquaculture tank (20) and are raised to multiple positions above or below the water surface by a seedling lifting device (31).

[0054] The lifting device (31) includes a hoisting motor (32), a lifting wire (33), and a position sensor (34), and lifts the seaweed (30) to a set position according to the command of the control unit (40).

[0055] The environmental sensor unit (50) includes a flow rate sensor (42), a DO sensor (43), a water temperature sensor (44), a light intensity (PPFD) sensor (45), and an air temperature sensor (46), and measures environmental changes inside the land-based aquaculture tank (20) and inside the greenhouse structure (10) in real time and transmits them to the control unit (40).

[0056] Referring to FIG. 5, the control unit (40) includes a data collection unit (41), a prediction calculation unit (42), and a control command unit (43), and controls the environment control means, refrigerator (18), heat pump (27), flow rate forming means, and lifting device (31) of the greenhouse structure (10) in conjunction based on real-time measurements from the environment sensor unit (50) and prediction information received from the outside environment collection module (60).

[0057] The control unit (40) can be applied to any method of machine learning, deep learning, fuzzy control, predictive control, rule-based control, PLC control, or timer control.

[0058] The system according to the present invention is operated according to the following interlocking control scenario.

[0059] When air temperature exceeds 22℃: open skylight (12) → deploy shading screen (14) → operate refrigerator (18)

[0060] When the water temperature exceeds 18℃: Heat pump (27) cooling operation → Work (30) immersion in water

[0061] When the air temperature is below the set lower limit: the thermal screen (15) deploys → the skylight (12) closes.

[0062] When the water temperature is less than 10℃: Heat pump (27) heating operation

[0063] When PPFD exceeds the upper limit: deploy the shading screen (14) → lower the work (30) underwater

[0064] Referring to FIG. 6, the system according to the present invention operates a cycle of growth stages repeatedly throughout the year.

[0065] In a preferred embodiment of the present invention, the appropriate range for each environmental variable is as follows.

[0066] Explanation of the symbols

[0067] 1: Land-based seaweed farming system 10: Greenhouse Structure 11: Translucent skin 12: Skylight 13: Skylight drive motor 14: Light-blocking screen 15: Thermal screen 16: Shade screen drive motor 17: Thermal screen drive motor 18: Freezer 20: Land-based aquaculture tank 21: Network structure 22: Inlet 23: Water return outlet 24: Bottom Upflow Nozzle 25: Circulation pump 26: Ringblower 27: Heat pump 30: Seaweed work 31: Employee elevator 32: Hoisting motor 33: Lifting wire 34: Position sensor 40: Control unit 41: Data Collection Department 42: Flow rate sensor 43: DO sensor 44: Water temperature sensor 45: Light intensity (PPFD) sensor 46: Air temperature sensor 50: Environmental sensor unit 60: Outdoor environment collection module

Claims

Claim 1 A greenhouse-based control system for land-based cultivation of seaweed comprises: a greenhouse structure (10) including a transparent outer shell (11) and a chiller (18) for cooling the air inside the greenhouse; a land-based cultivation tank (20) disposed inside the greenhouse structure (10); a flow rate forming means for controlling the water environment inside the land-based cultivation tank (20) and a heat pump (27) for heating or cooling the water temperature; and an environmental sensor unit (50) for measuring at least two of light intensity, water temperature, and dissolved oxygen (DO). A control system based on a greenhouse for land-based cultivation of seaweed, comprising a control unit (40) that controls the environment control means of the greenhouse structure (10), the flow rate forming means, the chiller (18), and the heat pump (27) in conjunction based on the measurement value of the environment sensor unit (50), wherein the control unit (40) controls at least two of the light environment, the thermal environment, and the water environment in combination according to the change in the environment inside the greenhouse, and wherein the flow rate forming means is composed of at least two combinations of a side wall inlet (22), a bottom upward flow nozzle (24), a return port (23), an oxygen supply device (26), and a circulation pump (25) to simultaneously form at least two of horizontal flow, upward flow, and surface return flow. Claim 2 A greenhouse-based control system for land-based seaweed aquaculture according to claim 1, characterized in that the seaweed includes laver (Porphyra spp.). Claim 3 A greenhouse-based control system for land-based aquaculture of seaweed according to claim 1, wherein the transparent outer shell (11) is formed from at least one of a polymethyl methacrylate (PMMA) panel, a polycarbonate (PC) panel, glass, a polyethylene terephthalate (PET) film, a polyethylene (PE) film, and an ethylene-tetrafluoroethylene (ETFE) film. Claim 4 A greenhouse-based control system for land-based cultivation of seaweed, characterized in that, in claim 1, it further includes a seaweed lifting device (31) for lifting the seaweed (30) to multiple positions above or below the water surface, and the control unit (40) controls the operation of the seaweed lifting device (31) according to changes in environmental conditions. Claim 5 A greenhouse-based control system for land-based seaweed aquaculture according to claim 1, further comprising an external environment collection module (60), wherein the control unit (40) receives weather forecast information or solar radiation forecast information from the external environment collection module (60) to predict environmental changes and preemptively control them. Claim 6 A greenhouse-based control system for land-based cultivation of seaweed according to claim 1, wherein the chiller (18) performs cooling operation when the air temperature inside the greenhouse exceeds 22℃, and the heat pump (27) performs cooling operation when the water temperature exceeds 18℃ and heat operation when the water temperature is less than 10℃. Claim 7 delete Claim 8 A method for controlling the environment for cultivating seaweed in a land-based aquaculture tank placed within a greenhouse structure, comprising: (a) a step of measuring at least two of light intensity, water temperature, dissolved oxygen (DO), flow rate, and air temperature through an environmental sensor unit; (b) a step of determining an environmental change based on the measured values; and (c) a step of controlling at least one of an environmental control means of the greenhouse structure, a chiller, a heat pump, and a flow rate forming means of the land-based aquaculture tank according to the determination result, wherein step (c) controls a plurality of control means in conjunction by considering the interaction of at least two of the light environment, thermal environment, and water environment, wherein when the air temperature exceeds 22℃, opening the roof window, deploying a shading screen, and operating the chiller are performed sequentially, and when the water temperature exceeds 18℃, cooling operation of the heat pump is performed. Claim 9 delete Claim 10 A method for controlling the environment of land-based seaweed aquaculture according to claim 8, further comprising the step of receiving weather forecast information from an external environment collection module, wherein step (c) predicts environmental changes based on the weather forecast information and controls them preemptively.

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