JP7633497B2 - Nutrient solution heating sterilization system and installation method of said nutrient solution heating sterilization system - Google Patents

Description

The present invention relates to a nutrient solution heating and sterilization system for nutrient solution used when cultivating plants using nutrient solution cultivation, and a method for installing the nutrient solution heating and sterilization system on an existing plant cultivation system.

In artificial environments such as plant factories, the nutrient solution used to grow plants using nutrient culture must be sterilized (removed bacteria) to prevent plant diseases. Incidentally, nutrient culture can be broadly divided into closed and non-closed systems (flow-through type). Closed systems are classified into circulating types (applicable to, for example, NFT (thin film hydroponic), DFT (deep-soil circulating hydroponic), various solid medium cultures, and small-volume soil medium cultures) and non-circulating types (applicable to, for example, capillary hydroponic, passive hydroponic, and water-retentive sheet culture) in terms of the nutrient solution circulation method. Also, non-closed systems are applicable to, for example, various solid medium cultures and small-volume soil medium cultures.

As an example, Patent Document 1 proposes a method for sterilizing nutrient solution using ozone, ultraviolet light, and photocatalyst. However, according to the knowledge of the present inventor, it is not easy to make the "fungi" in the nutrient solution, which is said to account for about 80% of the bacteria that cause plant diseases, negative using these sterilization methods. In order to make them negative, the concentration and strength of ozone, ultraviolet light, and photocatalyst must be increased, which in turn causes some fertilizer elements to become insoluble or precipitate, disrupting the composition balance of the fertilizer elements in the nutrient solution, creating a vicious cycle. In addition, the water treatment device described in Patent Document 1 is connected to the waste liquid tank by a nutrient liquid supply pipe and a nutrient liquid return pipe. However, in order to install the water treatment device, the nutrient liquid supply pipe, and the nutrient liquid return pipe, sufficient space is required near the waste liquid tank, and if there is not enough space, there is a problem that the water treatment device cannot be installed.

On the other hand, Patent Document 2 proposes a device for sterilizing nutrient solution (liquid fertilizer) by heating. This type of heating method is advantageous in that it is less likely to upset the composition balance of the fertilizer elements in the nutrient solution.

However, the sterilization device described in Patent Document 2 is configured to heat and sterilize the entire amount of circulating nutrient solution. This requires a large amount of energy for heating, which has the disadvantage that the heating device constituting the sterilization device must have a large capacity. In addition, if heated nutrient solution is directly supplied to the plants, the plants will be adversely affected by the heat, so the nutrient solution needs to be cooled after heating. Even in this case, the method of sterilizing the entire amount as in Patent Document 2 requires a large amount of energy for cooling. Furthermore, as with Patent Document 1, there is a problem in that the sterilization device cannot be installed if there is not enough space.

International Publication No. 2011/043326 Japanese Patent Application Publication No. 3-127918

The present invention aims to provide a nutrient solution heating and sterilization system that uses a heating method that does not easily upset the composition balance of the fertilizer elements in the nutrient solution and can be installed even when there is not enough space near the first tank that stores the nutrient solution, and an installation method for retrofitting the nutrient solution heating and sterilization system to an existing plant cultivation system.

The nutrient solution heating and sterilization system of the present invention is a nutrient solution heating and sterilization system that is installed in a plant cultivation system that is installed across multiple installation areas, and includes a first tank that stores nutrient solution, a cultivation tank in which a plant is cultivated with the nutrient solution, and a supply path through which the nutrient solution flows between the first tank and the cultivation tank. The nutrient solution heating and sterilization system includes a second tank that is installed in an installation area different from the installation area in which the first tank is installed and temporarily stores the nutrient solution supplied from the first tank, a connecting pipe through which the nutrient solution flows between the middle of the supply path and the second tank, and a sterilization system that is connected to the second tank and heats and sterilizes the nutrient solution supplied to the second tank.

With this configuration, the second tank is positioned so that the nutrient solution is supplied from the middle of the supply path through the connecting pipe, so the nutrient solution heating and sterilization system can be installed anywhere.

The system may also include a heating tank having a capacity to temporarily store the nutrient solution and equipped with a heating device for heating the stored nutrient solution, an outward piping from the second tank to the heating tank and a return piping from the heating tank to the second tank, a nutrient solution heating circulation mechanism for circulating the nutrient solution between the second tank and the heating tank, and a heat exchanger provided across the outward piping and the return piping for transferring heat of the nutrient solution flowing in the return piping to the nutrient solution flowing in the outward piping.

According to this configuration, a heating tank is provided separately from the second tank, and the nutrient solution is circulated through a heating nutrient solution circulation mechanism, so the capacity of the heating device can be reduced compared to a configuration in which the entire amount of nutrient solution for cultivating plants is heated.

The connecting pipe can also form part of a first flow path through which the nutrient solution flows from the first tank to the second tank, and part of a second flow path through which the nutrient solution flows from the second tank to the cultivation tank.

With this configuration, the connecting pipe constitutes part of the second flow path, so the nutrient solution that has been heated and sterilized by the nutrient solution heating and sterilization system can be sent directly to the cultivation tank, allowing the nutrient solution to be supplied to the plants without losing its sterilization effect.

The method for installing a nutrient solution heating and sterilizing system of the present invention is a method for adding a nutrient solution heating and sterilizing system to an existing plant cultivation system that is installed across multiple installation areas and includes a first tank for storing nutrient solution, a cultivation tank for cultivating plants with the nutrient solution, and a supply path through which the nutrient solution flows between the first tank and the cultivation tank, and includes a second tank for temporarily storing the nutrient solution supplied from the first tank, and a sterilization system connected to the second tank and for heat-sterilizing the nutrient solution supplied to the second tank, the method including a heat-sterilization system installation step for installing the nutrient solution heating and sterilizing system at an arbitrary position, and a connection step for providing a connecting pipe between the supply path and the second tank through which the nutrient solution can flow, and in the heat-sterilization system installation step, at least the second tank is installed in an installation area different from the installation area in which the first tank is installed.

With this configuration, the nutrient solution heating and sterilization system can be installed at any position and the first tank and the supply path are connected with a connecting pipe, so that even if there is not enough space near the existing plant cultivation system, the nutrient solution heating and sterilization system can be added.

The present invention provides a nutrient solution heating and sterilization system that uses a heating method that does not easily upset the composition balance of the fertilizer elements in the nutrient solution and can be installed even when there is not enough space near the first tank that stores the nutrient solution, as well as an installation method for retrofitting the nutrient solution heating and sterilization system to an existing plant cultivation system.

FIG. 1 is a diagram showing an existing plant cultivation system. FIG. 1 is a diagram showing a plant cultivation system incorporating a nutrient solution heating cultivation system according to one embodiment of the present invention.

A nutrient solution heating and sterilizing system 2 according to one embodiment of the present invention will be described with reference to Figures 1 and 2. The nutrient solution heating and sterilizing system 2 is incorporated into a plant cultivation system 1 as shown in Figure 1. In this embodiment, a case in which the nutrient solution heating and sterilizing system 2 is added to an existing plant cultivation system 1 will be described. First, each component will be described before describing the installation method for adding the nutrient solution heating and sterilizing system 2.

As shown in FIG. 1, the plant cultivation system 1 is a system for cultivating plants with nutrient solution in a cultivation tank 12. Specifically, the plant cultivation system 1 includes a first tank 11 for storing nutrient solution, a cultivation tank 12 for cultivating plants with nutrient solution, and a supply path 13 through which the nutrient solution flows between the first tank 11 and the cultivation tank 12. The plant cultivation system 1 of this embodiment adopts a circulation system in which the nutrient solution circulates within the system. The nutrient solution used in this embodiment is an aqueous solution in which water-soluble components useful for plants, such as nutrients for growing plants and medicines for preventing plants from getting sick, are dissolved, and circulates through each part of the plant cultivation system 1. Such a plant cultivation system 1 is installed, for example, in a building. In addition, the plant cultivation system 1 is installed across multiple installation areas of the building. The plant cultivation system 1 of this embodiment is installed across multiple floors of a building, for example, from the first floor to the second floor of a building. The plant cultivation system 1 may be installed across multiple rooms (sections) on one floor of a building, or across multiple buildings.

The cultivation tank 12 is a portion for cultivating plants, and has a certain volume so that the nutrient solution comes into contact with the roots of the plants. The cultivation tank 12 is connected to a supply path 13 (supply pipe 131 and drain pipe 132) through which the nutrient solution flows in and out in one direction, as shown by the arrow. Although not shown, the cultivation tank 12 is provided with a support portion for supporting the roots of the plants to be cultivated. Also, although not shown, in the case of a completely artificial light type plant factory, a lighting device is provided around the cultivation tank 12 (for example, above the cultivation tank 12) and irradiates light for growing the plants. In this embodiment, three cultivation tanks 12 are provided in parallel. However, the number of cultivation tanks 12 is not limited to this. Also, when multiple cultivation tanks 12 are provided, each cultivation tank 12 can be arranged vertically or horizontally. Also, the plants cultivated in the cultivation tank 12 can be various plants suitable for nutrient solution cultivation, such as leafy vegetables. The cultivation tank 12 in this embodiment is provided on the second floor of the building.

The first tank 11 is a tank with a certain capacity for storing nutrient solution for cultivating plants. The capacity of the first tank 11 is set to a capacity that allows for some leeway for the nutrient solution that remains in the cultivation tank 12 and circulates through the supply path 13 (supply pipe 131 and drainage pipe 132). The capacity of the first tank 11 in this embodiment is, for example, 500 liters. The first tank 11 in this embodiment is also provided on the first floor of a building.

The supply path 13 is a mechanism for circulating the nutrient solution between the first tank 11 and the cultivation tank 12. The supply path 13 includes a supply pipe 131 from the first tank 11 to the cultivation tank 12, and a drain pipe 132 from the cultivation tank 12 to the first tank 11. A first nutrient solution circulation pump 133 for cultivation is provided in the middle of the supply pipe 131. Although not shown, a refilling mechanism for refilling the nutrient solution or the components in the nutrient solution that have been lost due to absorption by plants or evaporation in the cultivation tank 12 is provided in the first tank 11 or the supply path 13. The supply pipe 131 of this embodiment supplies the nutrient solution from the first tank 11 provided on the first floor to the cultivation layer provided on the second floor by the first nutrient solution circulation pump 133 for cultivation. In addition, the drain pipe 132 allows the nutrient solution drained by, for example, overflow from the cultivation tank 12 provided on the second floor to fall according to gravity and guide it to the first tank 11.

The nutrient solution heating and sterilization system 2 includes a second tank 21 that temporarily stores the nutrient solution supplied from the first tank 11, a connecting pipe 22 that connects the supply path 13 and the second tank 21 so that the nutrient solution flows between them, and a sterilization system 3 that is connected to the second tank 21 and heats and sterilizes the nutrient solution supplied to the second tank 21. The nutrient solution heating and sterilization system 2 of this embodiment also includes a cooling device 23 that cools the nutrient solution stored in the second tank 21, and a cooling nutrient solution circulation mechanism 24.

The second tank 21 is a tank having a certain capacity for storing the nutrient solution. The capacity of the second tank 21 is set to a capacity that allows for some leeway for the amount of nutrient solution that remains in the cultivation tank 12 and circulates through the supply path 13 (the supply pipe 131 and the drain pipe 132). In this embodiment, the capacity of the second tank 21 is, for example, 500 liters. The capacity of the second tank 21 is approximately equal to the capacity of the first tank 11. Therefore, even if the entire amount of nutrient solution stored in the first tank 11 is supplied to the second tank 21, it is possible to prevent the nutrient solution from overflowing from the second tank 21 (not being able to be stored).

The second tank 21 in this embodiment is installed in a different installation area from the first tank 11. The second tank 21 in this embodiment is installed on a different floor in the same building as the first tank 11. Note that the second tank 21 can also be installed in a different room on the same floor in the same building as the first tank 11, or the first tank 11 and the second tank 21 can be installed in different buildings, or the first tank 11 can be installed outdoors and the second tank 21 indoors.

The connecting pipe 22 connects the middle of the supply path 13 to the second tank 21, and is a pipe through which the nutrient solution flows between the supply path 13 and the second tank 21. The connecting pipe 22 in this embodiment is connected to the middle of the supply pipe 131. The connecting pipe 22 also includes a first connecting pipe 221 that flows the nutrient solution from the supply pipe 131 to the second tank 21, and a second connecting pipe 222 that flows the nutrient solution from the second tank 21 to the supply pipe 131. The connection point between the first connecting pipe 221 and the supply pipe 131 is located closer to the first tank 11 in the direction in which the nutrient solution of the supply pipe 131 flows than the connection point between the second connecting pipe 222 and the supply pipe 131. That is, the first connecting pipe 221 forms a part of the first flow path R1 through which the nutrient solution flows from the first tank 11 to the second tank 21, and the second connecting pipe 222 forms a part of the second flow path R2 through which the nutrient solution flows from the second tank 21 to the cultivation tank 12. In addition, a second nutrient solution circulation pump 223 is provided in the middle of the second connecting pipe 222. The second nutrient solution circulation pump 223 transfers the nutrient solution from the second tank 21 to the cultivation tank 12. With the connecting pipe 22 configured in this way, as described below, the nutrient solution in the second tank 21 that has been heat-sterilized and temperature-regulated (cooled) can be sent directly to the cultivation tank 12, so that the nutrient solution can be supplied to the plants in the cultivation tank 12 without losing the sterilization effect.

The sterilization system 3 is provided to sterilize the nutrient solution. The bacteria to be sterilized are, for example, fungi. The sterilization system 3 mainly comprises a heating tank 31, a heating nutrient solution circulation mechanism 32, and a heat exchanger 33. Note that the sterilization system 3 is not limited to this configuration, and various configurations capable of heat sterilizing the nutrient solution can be adopted.

The heating tank 31 has a capacity to temporarily store the nutrient solution. The heating tank 31 is equipped with a heating device 311 that heats the stored nutrient solution. The heating device 311 in this embodiment is an electric heater. However, this is not limited to this, and various types of heating devices 311 can be used. Other types of heating devices 311 include an oil boiler and a gas boiler. In the nutrient solution heating and sterilization system 2 of this embodiment, since the temporarily stored nutrient solution is heated, the amount of nutrient solution to be heated can be smaller than the amount of nutrient solution circulating between the first tank 11 and the cultivation tank 12. In other words, compared to the conventional method of sterilizing the entire amount of the nutrient solution, the amount of nutrient solution to be heated can be reduced in some cases. This contributes to energy conservation. Accordingly, the capacity of the heating tank 31 can be set smaller than the capacity of the second tank 21. The capacity of the heating tank 31 in this embodiment is, for example, 200 liters, which is smaller than the capacity of the second tank 21 (for example, 500 liters). This can reduce the installation space of the heating tank 31, which may contribute to space saving of the nutrient solution heating and sterilization system 2 (the entire plant cultivation system 1). In addition, the heating tank 31 is provided with a temperature sensor (not shown), and heating is controlled by a connected control device (not shown).

The nutrient solution circulation mechanism for heating 32 includes an outward pipe 321 leading from the second tank 21 to the heating tank 31, and a return pipe 322 leading from the heating tank 31 to the second tank 21. The nutrient solution circulation mechanism for heating 32 circulates the nutrient solution between the second tank 21 and the heating tank 31 via the outward pipe 321 and the return pipe 322. For this circulation, a heating outward pump 323 is provided in the outward pipe 321, and a heating return pump 324 is provided in the return pipe 322. In the nutrient solution circulation mechanism for heating 32 of this embodiment, each pump can move, for example, 20 liters of nutrient solution per minute.

The nutrient solution in the second tank 21 returns to the second tank 21 via the outward piping 321, the heating tank 31, and the return piping 322. In this way, the nutrient solution circulates for heating. The circulation may be continuous without interruption, or may be intermittent as a batch process. The latter is adopted in this embodiment. In the latter case, the nutrient solution stored in the heating tank 31 and the amount of nutrient solution that has been stopped from flowing in and out can be heated, which has the advantage of making it easier to control the temperature.

The heat exchanger 33 is provided between the forward pipe 321 and the return pipe 322. The heat exchanger 33 transfers the heat of the nutrient solution flowing in the return pipe 322 to the nutrient solution flowing in the forward pipe 321. The heat exchanger 33 in this embodiment is a plate-type heat exchanger 33. However, this is not limited to this, and various types of heat exchangers 33 can be used. If heat loss is ignored, the temperature rise of the nutrient solution on the forward pipe 321 side in the heat exchanger 33 is the same as the temperature drop of the nutrient solution on the return pipe 322 side. Specific examples of temperature changes will be described later. With a heat exchanger 33 configured in this way, the nutrient solution can be heated just before it is supplied to the heating tank 31 and cooled just before it is returned to the second tank 21, improving the efficiency of heating and cooling.

The cooling device 23 cools the nutrient solution stored in the second tank 21. The cooling device 23 in this embodiment is a chiller. However, this is not limited to this, and various types of cooling devices 23 can be used. The cooling nutrient solution circulation mechanism 24 is equipped with a cooling pump and circulates the nutrient solution between the second tank 21 and the cooling device 23. The cooling nutrient solution circulation mechanism 24 is provided separately from the heating nutrient solution circulation mechanism 32. Therefore, it is possible to appropriately cool the nutrient solution that has been lowered in temperature by the heat exchanger 33 and returned to the second tank 21 without excessive (overcooling). In this embodiment, the cooling device 23 is operated continuously together with the cooling nutrient solution circulation mechanism 24, but may be operated intermittently. The cooling device 23 can appropriately lower the temperature of the nutrient solution in the second tank 21, so that it is possible to prevent the heat of the nutrient solution from adversely affecting the plants in the cultivation tank 12. That is, the nutrient solution heating and sterilization system 2 in this embodiment can heat and sterilize the nutrient solution in the second tank 21 and adjust the temperature.

The following describes a method for installing the nutrient solution heating and sterilizing system 2 described above to an existing plant cultivation system 1. The installation of the nutrient solution heating and sterilizing system 2 is performed through a heating and sterilizing system installation process and a connection process.

The heat sterilization system installation process is a process of installing the nutrient solution heating sterilization system 2 at any position (at a position where there is sufficient space for installing the nutrient solution heating sterilization system 2). In this embodiment, the nutrient solution heating sterilization system 2 is installed on the second floor of the building (the same floor as the floor on which the cultivation tank 12 is installed). In addition, in the heat sterilization system installation process, the second tank 21 is installed in an installation area different from the installation area in which the first tank 11 is installed.

The connecting process is a process of connecting the supply path 13 and the second tank 21 with the connecting pipe 22. In the connecting process, the first connecting pipe 221 and the second connecting pipe 222 are installed between the supply path 13 and the second tank 21, respectively. In the connecting process, the connecting pipe 22 (the first connecting pipe 221 and the second connecting pipe 222) is installed between the supply pipe 131 and the second tank 21. In the connecting process, the opening and closing valve 134 is installed at a predetermined position of the supply path 13 and the connecting pipe 22. Specifically, the opening and closing valve 134 is arranged at a position between the connecting point to which the first connecting pipe 221 is connected and the connecting point to which the second connecting pipe 222 is connected, and at a position in the middle of each of the first connecting pipe 221 and the second connecting pipe 222. By arranging the on-off valve 134 in this manner, it is possible to appropriately select whether the nutrient solution is supplied from the first tank 11 to the cultivation tank 12 via the nutrient solution heating and sterilization system 2, or whether the nutrient solution is supplied directly from the first tank 11 to the cultivation tank 12 without going through the nutrient solution heating and sterilization system 2. According to this type of connection process, the nutrient solution heating and sterilization system 2 can be added to an existing plant cultivation system 1 by processing the supply path 13, so that the nutrient solution heating and sterilization system 2 can be installed more easily than when processing the first tank 11.

According to the above process, the nutrient solution heating and sterilization system 2 can be installed at any position and the second tank 21 and the supply path 13 are connected by the connecting pipe 22, so that the nutrient solution heating and sterilization system 2 can be added even if there is not enough space near the first tank 11 of the existing plant cultivation system 1.

Next, we will explain the operation of the nutrient solution heating and sterilization system 2 using an example.

At the first time (when the second tank 21 and the heating tank 31 are empty), the first cultivation nutrient solution circulation pump 133 is operated to move the nutrient solution in the first tank 11 to the second tank 21, and a certain amount of nutrient solution is stored in the second tank 21. When a certain amount of nutrient solution is stored in the second tank 21, the heating forward pump 323 is operated to store an amount of nutrient solution to be sterilized at one time in the heating tank 31. At this time, nutrient solution may be supplied from the first tank 11 to the second tank 21 in parallel with the supply of nutrient solution to the heating tank 31. Next, the heating forward pump 323 is stopped, and the heating device 311 (electric heater) is operated to heat the nutrient solution in the heating tank 31 to 60 to 70°C.

From the second time onwards (when nutrient solution has already accumulated in the heating tank 31), the heating forward pump 323 and the heating return pump 324 are operated simultaneously, and heat is exchanged between the high-temperature and low-temperature nutrient solutions in the heat exchanger 33. As a result, nutrient solution at 45-55°C enters the heating tank 31, and nutrient solution at 35-45°C returns to the second tank 21. Next, the heating forward pump 323 and the heating return pump 324 are stopped, and the heating device 311 (electric heater) is operated to heat the 45-55°C nutrient solution in the heating tank 31 to 60-70°C. After heating, the heating device 311 continues to operate to maintain (keep warm) the temperature at 60-70°C for several minutes to 30 minutes. Next, the nutrient solution at about 25°C in the second tank 21 is mixed with the nutrient solution at 35-45°C that has returned to the second tank 21, and the nutrient solution in the second tank 21 rises by several degrees above about 25°C (the temperature rise varies depending on the mixing ratio). Because the returned mixed volume is small compared to the volume of the second tank 21, the temperature rise of the nutrient solution in the second tank 21 is kept small. The increased temperature is cooled to about 25°C by the cooling device 23 (chiller). By repeating these steps, the sterilization process is carried out sequentially.

The present invention has been described above with reference to one embodiment, but the present invention is not limited to the embodiment described above, and various modifications are possible without departing from the spirit of the present invention.

For example, although the case where the nutrient solution heating and sterilization system 2 is added to an existing plant cultivation system 1 has been described, the nutrient solution heating and sterilization system 2 can also be applied to a newly constructed plant cultivation system 1. Specifically, even when a new plant cultivation system 1 is constructed, or when there is not enough space for installing the nutrient solution heating and sterilization system 2 near the first tank 11, the nutrient solution heating and sterilization system 2 can be installed.

Although the case where the connecting pipe 22 is connected to the supply pipe 131 has been described, in the circulation type plant cultivation system 1, the connecting pipe 22 may be configured to be connected to the drain pipe 132. In such a configuration, the heated and sterilized nutrient solution is supplied to the first tank 11 and then flows into the cultivation tank 12, so that heat is dissipated before the nutrient solution is supplied to the cultivation tank 12. Therefore, even if the nutrient solution heating and sterilization system 2 does not include a cooling device 23 or the capacity of the cooling device 23 is small, it is possible to prevent the heat of the nutrient solution from adversely affecting the plants.

1...Plant cultivation system, 11...First tank, 12...Cultivation tank, 13...Supply path, 131...Supply pipe, 132...Drainage pipe, 133...First cultivation nutrient solution circulation pump, 134...Opening and closing valve, 2...Nutrient solution heating and sterilization system, 21...Second tank, 22...Connecting pipe, 221...First connecting pipe, 222...Second connecting pipe, 223...Second cultivation nutrient solution circulation pump, 23...Cooling device, 24...Nutrient solution circulation mechanism for cooling, 3...Sterilization system, 31...Heating tank, 311...Heating device, 32...Nutrient solution circulation mechanism for heating, 321...Outward pipe, 322...Return pipe, 323...Heating forward pump, 324...Heating return pump, 33...Heat exchanger, R1...First flow path, R2...Second flow path

Claims (4)

A nutrient solution heating and sterilization system comprising: a first tank for storing a nutrient solution; a cultivation tank for cultivating a plant with the nutrient solution; and a supply path through which the nutrient solution flows between the first tank and the cultivation tank, the nutrient solution heating and sterilization system being installed in a plant cultivation system installed across a plurality of installation areas,
A second tank that is installed in an installation area different from the installation area in which the first tank is installed and temporarily stores the nutrient solution supplied from the first tank;
A connecting pipe through which the nutrient solution flows between the middle of the supply path and the second tank;
A nutrient solution heating and sterilization system comprising: a sterilization system connected to the second tank and heat-sterilizing the nutrient solution supplied to the second tank. A nutrient solution heating and sterilization system comprising: a first tank for storing a nutrient solution; a cultivation tank for cultivating a plant with the nutrient solution; and a supply path through which the nutrient solution flows between the first tank and the cultivation tank, the nutrient solution heating and sterilization system being installed in a plant cultivation system installed across a plurality of installation areas,
A second tank that is installed in an installation area different from the installation area in which the first tank is installed and temporarily stores the nutrient solution supplied from the first tank;
A connecting pipe through which the nutrient solution flows between the middle of the supply path and the second tank;
A sterilization system connected to the second tank and heat-sterilizing the nutrient solution supplied to the second tank ,
The sterilization system comprises:
A heating tank having a capacity for temporarily storing the nutrient solution and equipped with a heating device for heating the stored nutrient solution;
a nutrient solution heating and sterilization system comprising: a forward piping from the second tank to the heating tank, and a return piping from the heating tank to the second tank, and a heating nutrient solution circulation mechanism which circulates the nutrient solution between the second tank and the heating tank. The sterilization system includes a heat exchanger provided between the outward piping and the return piping and configured to transfer heat of the nutrient solution flowing in the return piping to the nutrient solution flowing in the outward piping,
The nutrient solution heating and sterilization system according to claim 2, wherein the connecting pipe constitutes a part of a first flow path through which the nutrient solution flows from the first tank to the second tank and a part of a second flow path through which the nutrient solution flows from the second tank to the cultivation tank. An existing plant cultivation system including a first tank for storing a nutrient solution, a cultivation tank for cultivating plants with the nutrient solution, and a supply path through which the nutrient solution flows between the first tank and the cultivation tank, the existing plant cultivation system being installed across a plurality of installation areas,
A second tank for temporarily storing the nutrient solution supplied from the first tank;
A method for additionally installing a nutrient solution heating and sterilizing system comprising: a sterilization system connected to the second tank and heats and sterilizes the nutrient solution supplied to the second tank;
A heat sterilization system installation step of installing the nutrient solution heat sterilization system at an arbitrary position;
A connecting step of providing a connecting pipe between the supply path and the second tank through which the nutrient solution can flow,
The method for installing a nutrient solution heating and sterilizing system, wherein, in the step of installing the heating and sterilizing system, at least the second tank is installed in an installation area different from the installation area in which the first tank is installed.

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