JP7735221B2 - Temperature Control Unit - Google Patents

Description

The present invention relates to a temperature control unit that adjusts the temperature of a liquid to a constant temperature.

Conventionally, systems are known that adjust the temperature in a room or the like using hot water heated by a heating device that uses electricity or gas (see, for example, Patent Document 1). The hot water heating system described in Patent Document 1 includes a hot water heating heat source machine that generates hot water, and a hot water heating terminal device that provides heating using the hot water generated by the hot water heating heat source machine.

Japanese Patent Application Laid-Open No. 2006-46816

However, with the system described in Patent Document 1, once the system is turned off, the temperature of the circulating hot water drops significantly, especially during cold weather. Then, when the system is turned back on to use it, a large amount of power is consumed to raise the temperature of the hot water to a temperature suitable for heating, which is undesirable from an energy conservation perspective.

The object of the present invention is to provide a temperature control unit that can suppress a drop in liquid temperature and achieve energy savings.

The temperature control unit of the present invention comprises a tank buried underground, formed in the shape of a hollow box with an enclosed space inside; an internal chamber housed within the tank, formed in the shape of a hollow box with an enclosed space inside; a liquid inlet section that introduces a first liquid into the internal chamber; a liquid outlet section that discharges the first liquid from the internal chamber to the outside; and a second liquid filled between the tank and the internal chamber.

The temperature control unit preferably includes a heating device disposed inside the internal chamber that heats the first liquid introduced by the liquid introduction portion.

In the above temperature control unit, it is preferable that the heating device be formed in a longitudinal shape, one end be connected to the liquid inlet port and the other end be connected to the liquid outlet port, and that the heating device be provided with a spirally arranged liquid heating section around the outer periphery of the heating device, through which the first liquid flows.

It is preferable that the above temperature control unit further includes a heat retention section that covers the outer surface of the tank.

1 is a schematic diagram showing a general configuration of a temperature adjustment system according to an embodiment of the present invention; FIG. 2 is a plan view of the road heater according to the embodiment. FIG. 1 is a cross-sectional view schematically showing the general configuration of a temperature control unit according to the present embodiment. FIG. 4 is a diagram showing the temperature of the first liquid flowing in the internal chamber of the temperature control unit of the present embodiment. FIG. 11 is a schematic diagram showing a general configuration of a temperature adjustment system according to a second modification.

The configuration of a temperature control system according to one embodiment of the present invention will be described below. The temperature control system 1 of the present invention is a system that adjusts the temperature of a space using a temperature control device such as a road heater while achieving energy conservation. The heat medium of the temperature control system 1 is a liquid, such as water or antifreeze.

[Overall configuration of temperature control system]
FIG. 1 is a schematic diagram showing the overall configuration of a temperature adjustment system 1 according to this embodiment.
As shown in FIG. 1 , the temperature adjustment system 1 of this embodiment includes a load heater 2 that adjusts the ambient temperature using the heat of a heated liquid (the first liquid of the present disclosure), a temperature control unit 3 that controls the temperature of the liquid supplied to the load heater 2 to a constant temperature, a liquid circulation device 4 that circulates the liquid between the temperature control unit 3 and the load heater 2, and a controller 5 that controls the temperature adjustment system 1.

[Configuration of Load Heater 2]
First, the road heater 2, which is the temperature control device of this embodiment, will be described.
FIG. 2 is a schematic diagram showing the general configuration of the load heater 2.
The temperature control device described here is a device that controls the temperature of an object by using a first liquid whose temperature is controlled by a temperature control unit 3. In this embodiment, a road heater 2 is used as an example of the temperature control device, but the temperature control device is not limited to this and may be, for example, an air conditioning device that controls the indoor temperature of a living space.
In this embodiment, the road heater 2 is a device that melts snow using a liquid such as warm antifreeze, the temperature of which is controlled and heated by the temperature control unit 3. The road heater 2 in this embodiment is a foldable road heater that can be folded up for easy portability.
As shown in FIG. 2, the load heater 2 has a first load heater piece 11 and a second load heater piece 12 that can be stacked on top of each other.
The first load heater segment 11 has a plate-shaped first main body portion 13 and a first pipe 14 that snakes inside the first main body portion 13. The first main body portion 13 is formed of, for example, hard plastic or metal.

The first main body 13 may have a length of 180 cm and a width of 90 cm, for example. The first main body 13 is preferably sized to be portable, and each side preferably has a length of 50 cm to 220 cm.
In addition, chamfered portions 15 are provided at the corners of the first main body portion 13. The chamfered portions 15 are formed so as to cut off the corners between the long and short sides of the first main body portion 13. The shape of the chamfered portions 15 is not limited to the angular chamfer shown in the drawing, and may also be rounded.

The first pipe 14 is a cross-linked polyethylene pipe. In this embodiment, the diameter of the first pipe 14 is 100 mm, but this can be changed as appropriate depending on the size of the first main body portion 13, the type of liquid flowing therethrough, and the like. The first pipe 14 is not limited to a cross-linked polyethylene pipe, and other pipes can be used as long as they are flexible and have excellent corrosion resistance, impact resistance, and the like.
The first pipe 14 snakes inside the first main body portion 13, and the interval G1 between adjacent first pipes 14 is preferably 150 mm or more and 300 mm or less. The interval G1 can be adjusted appropriately depending on the diameter of the first pipe 14, etc., so as to achieve the most efficient operation.

The second load heater piece 12 has the same structure as the first load heater piece 11. That is, the second load heater piece 12 has a second main body portion 17 that is roughly the same shape as the first main body portion 13, and a second pipe 18 that snakes inside the second main body portion 17, and the second main body portion 17 has a chamfered portion 19.

The first pipe 14 and the second pipe 18 are connected via a connecting pipe 20. That is, the liquid flowing through the first pipe 14 flows into the second pipe 18 via the connecting pipe 20.
The first load heater piece 11 and the second load heater piece 12 are connected by a hinge 21. By connecting the first load heater piece 11 and the second load heater piece 12 by the hinge 21, it is possible to prevent excessive load from being applied to the connecting pipe 20 when carrying the device.

Connectors 22 are connected to the ends of the first pipe 14 and the second pipe 18 opposite the connecting pipe 20. The connectors 22 are connected to the liquid feed pipe 41 and the liquid return pipe 42, which will be described later.

The road heater 2 of this embodiment is foldable, so that it can be carried and installed on any desired path, such as an asphalt path or a tiled path.
Furthermore, the main body parts 13, 17 of the load heater 2 of this embodiment are provided with chamfered parts 15, 19, so that people will not trip over the corners.
In the above embodiment, the load heater 2 is divided into two sections, but this is not limited to this and the number of load heater sections may be three or more. Also, in this embodiment, a foldable load heater is used, but a normal built-in load heater can also be used in the temperature adjustment system of the present invention.
Furthermore, although the road heater 2 is exemplified as a temperature adjustment device, the present invention is not limited to this and may be any device that adjusts the temperature of an object using a liquid introduced from the temperature control unit 3. For example, the present invention may be a heating and cooling device for adjusting the room temperature inside a building such as a house or a greenhouse.

[Configuration of temperature control unit 3]
Next, the temperature control unit 3 for maintaining the liquid used in the load heater 2 within a certain temperature range will be described.
The temperature control unit 3 is buried at a predetermined depth (for example, 2 to 3 m) from the ground surface. For example, as shown in Fig. 1, the temperature adjustment system 1 includes an installation chamber 61 for installing the temperature control unit 3. The installation chamber 61 can be made of, for example, concrete, and at least a portion of it is buried underground.
A temperature control unit 3 is provided at the bottom of the installation chamber 61 , and the temperature control unit 3 is buried in the ground deeper than the bottom of the installation chamber 61 .
A liquid circulation device 4 is provided on the side of the installation chamber 61 to circulate liquid between the load heater 2 and the temperature control unit 3. In the example shown in Fig. 1, the liquid circulation device 4 is provided on the side of the installation chamber 61, but this is not limiting. For example, the liquid circulation device 4 may be provided outside the installation chamber 61, or may be provided integrally with the temperature control unit 3.

FIG. 3 is a cross-sectional view showing a schematic configuration of the temperature control unit 3.
3, the temperature control unit 3 includes a tank 31, an internal chamber 32 housed in the tank 31, and a heating device 33 disposed in the internal chamber 32. As described above, the temperature control unit 3 may be configured to be integrally provided with the liquid circulation device 4.

The tank 31 is formed in the shape of a hollow box with an enclosed space inside, and as described above, is buried underground from the bottom of the installation chamber 61, so that it is placed underground at a depth of, for example, 2 to 3 m below the surface.
Specifically, the tank 31 of this embodiment is formed in a cylindrical shape with a bottom and a vertical central axis, and includes a tank body 311 that is open at its vertical upper end. In this embodiment, the tank body 311 is formed to have an inner diameter of, for example, 300 mm. The tank body 311 can be formed of, for example, concrete, resin, or the like.
A tank lid 312 is provided at the vertical upper end of the tank body 311, and the tank lid 312 is connected to the tank body 311. An opening 313 is provided in the tank lid 312 and is centered on the central axis of the tank 31, and an internal chamber 32, which will be described later, is inserted into the opening 313.

The tank 31 is filled with a second liquid 314. This second liquid 314 can be water or antifreeze, and is filled between the inner wall of the tank 31 and the outer wall of the internal chamber 32. This second liquid 314 is not discharged to the outside during use, but is always filled within the tank 31. A second liquid inlet for introducing or discharging the second liquid 314 may be provided separately in the tank lid 312, in which case the second liquid 314 can also be replaced.

Furthermore, a heat-retaining section 315 made of a heat-insulating material such as foam is disposed on the outer periphery of the tank 31. The heat-retaining section 315 may be provided along the cylindrical outer periphery of the tank body 311 between it and the ground, or may be provided between the bottom of the tank body 311 and the ground. There are no particular restrictions on the thickness of the heat-retaining section 315, but a thickness of 6 cm or more is preferable to improve the heat-retaining effect.

The internal chamber 32 is formed in a hollow box shape, the interior of which is an airtight space, and is housed inside the tank 31. Specifically, the internal chamber 32 includes a steel pipe 321 inserted into the inside of the tank body 311 from the opening 313 of the tank lid 312, a second lid 322 connected to the upper end of the steel pipe 321, and a connector 323 provided on the upper part of the second lid 322.
In this embodiment, by joining the second lid portion 322 to the tank lid portion 312, the opening 313 of the tank lid portion 312 is closed and the inside of the tank 31 is sealed. There are no particular limitations on the method for joining the second lid portion 322 to the tank lid portion 312, and an example is a configuration in which the second lid portion 322 is fixed to the tank lid portion 312 with a fastening member such as a screw. Furthermore, a sealing member such as a packing may be disposed between the tank lid portion 312 and the second lid portion 322 as appropriate.

The steel pipe 321 is formed, for example, in a cylindrical shape with a bottom, and the upper end is closed by the second lid portion 322, thereby sealing the interior. For example, the horizontal width dimension of the steel pipe 321 is smaller than the horizontal width dimension of the tank body 311, and as described above, is a dimension that allows the steel pipe 321 to be inserted into the tank 31 through the opening 313. For example, in this embodiment, the tank body 311 and the steel pipe 321 are formed in a cylindrical shape with a bottom, the inner cylindrical diameter of the tank body 311 is 300.0 mm, and the outer cylindrical diameter of the steel pipe 321 is approximately 114.3 mm. Furthermore, when the steel pipe 321 is inserted into the tank 31, a gap of a predetermined dimension is provided between the bottom of the outer peripheral surface of the steel pipe 321 and the bottom of the inner peripheral surface of the tank body 311.
As described above, the inside of the tank 31 is filled with the second liquid 314. In other words, the steel pipe 321 is configured to be immersed in the second liquid 314 inside the tank 31.

A heating device 33 is provided inside the steel pipe 321. The configuration of the heating device 33 is not particularly limited, but an example thereof is a sheath heater that is inserted into the steel pipe 321 from the lower surface of the second lid portion 322 and extends longitudinally along the cylindrical central axis of the steel pipe 321.
Specifically, the second lid portion 322 has an attachment hole that penetrates the second lid portion 322 and into which the heating device 33 can be attached, and the heating device 33, such as a sheathed heater, is fixed by screwing into the attachment hole or the like. Furthermore, heater terminals 331 of the heating device 33 are exposed from the connector portion 323 and are connected to the controller 5. As a result, the heating device 33 is driven by power supplied from the controller 5.

Furthermore, the connector portion 323 is provided with a liquid inlet portion 323A and a liquid outlet portion 323B. These liquid inlet portion 323A and liquid outlet portion 323B are each connected from the connector portion 323 to the inside of the steel pipe 321, and are connected to a liquid spiral heating portion 332, which is a spiral pipe that is arranged in a spiral shape along the outer circumferential surface of the heating device 33, inside the steel pipe 321. In other words, one end of the liquid spiral heating portion 332 arranged inside the steel pipe 321 is connected to the liquid inlet portion 323A, and the other end is connected to the liquid outlet portion 323B.
The liquid introduction portion 323A and the liquid discharge portion 323B are each connected to the liquid circulation device 4 via the connector portion 323.
In this configuration, the first liquid cooled by flowing through the load heater 2 is sent to the liquid inlet 323A by the liquid circulation device 4. The first liquid sent to the liquid inlet 323A passes through the spiral liquid heating section 332 and flows toward the liquid outlet 323B, where it is heated by driving the heating device 33. The heated first liquid is then sent again from the liquid outlet 323B to the load heater 2 via the liquid circulation device 4.

In addition, although not shown, the temperature control unit 3 may be provided with a temperature sensor. For example, a temperature sensor may be provided in the liquid introduction portion 323A of the connector portion 323 to measure the temperature of the first liquid flowing from the liquid introduction portion 323A into the internal chamber 32. Alternatively, a temperature sensor may be provided in the liquid outlet portion 323B of the connector portion 323 to measure the temperature of the first liquid being discharged from the internal chamber 32. Alternatively, a configuration in which temperature sensors are provided in both the liquid introduction portion 323A and the liquid outlet portion 323B may be used.

[Configuration of liquid circulation device 4]
As described above, the liquid circulation device 4 is a pump that connects the load heater 2 and the temperature control unit 3 and circulates the first liquid.
That is, the liquid circulation device 4 has a liquid feed pipe 41 that feeds the first liquid sent from the temperature control unit 3 to the load heater 2, and a liquid return pipe 42 that returns the first liquid used in the load heater 2 to the temperature control unit 3. The liquid feed pipe 41 is connected to the liquid outlet portion 323B of the connector portion 323, and the liquid return pipe 42 is connected to the liquid introduction portion 323A of the connector portion 323.

[Configuration of controller 5]
The controller 5 is a device that receives instructions from a user, switches the mode of the temperature adjustment system 1 between the heating mode and the cooling mode, and monitors the temperature of the first liquid sent to the load heater 2. The controller 5 performs control based on, for example, the measurement value of a temperature sensor.

[Operation of Temperature Regulation System 1 by Controller 5]
Next, the operation of the temperature adjustment system 1 will be described.
The specific temperatures shown below are merely examples, and may be different depending on the environment, etc.

[Heating mode operation]
First, the operation of the temperature regulation system 1 when using the road heater 2 on days (for example, in winter) when the air temperature is below geothermal (10° C. to 15° C.) will be described.
The controller 5 sets the operation mode of the temperature regulation system 1 to the heating mode, for example, in response to a setting input by the user.

In this heating mode, the controller 5 operates the heating device 33 to a predetermined output. The output of the heating device 33 is sufficient to heat the liquid in the liquid spiral heating section 332, for example, to 80°C. The controller 5 also drives the liquid circulation device 4 to begin circulating the liquid. That is, the first liquid heated by the heating device 33 of the temperature control unit 3 is sent to the load heater 2 by the liquid circulation device 4 and circulates between the load heater 2 and the temperature control unit 3.

The liquid supplied to the road heater 2 is used by the road heater 2 to melt snow, etc., and then returned to the temperature control unit 3 via the liquid return pipe 42 by the liquid circulation device 4. The liquid returned to the temperature control unit 3 is reheated by the heating device 33 while passing through the liquid spiral heating section 332.

Note that the above is an example in which the user sets the operating mode to heating mode, but this is not limiting. For example, the controller 5 may set the operating mode to heating mode when the temperature measured by the temperature sensor is below a predetermined temperature. Alternatively, the controller 5 may control the heating device 33 to stop operating during the night.

In conventional systems for supplying hot water to road heaters, a heat pump is used to heat the liquid supplied to the road heater only when the road heater is in use. In this case, the temperature of the liquid rises when the heat pump is operated, but when the heat pump is stopped, the temperature drops rapidly, reaching a temperature of 30°C or less within an hour. If the pipes supplying the liquid to the road heater are buried underground, the temperature is prevented from dropping below geothermal levels, but it will fluctuate around the temperature underground.
In such a conventional configuration, when the heat pump is next driven to supply liquid to the load heater, the liquid needs to be heated to around 6 to 7 degrees Celsius, which requires a larger amount of heat, resulting in increased power consumption by the heat pump.
It is also possible to use a heater that uses fossil fuels instead of a heat pump, or to use a heat pump and a heater that uses fossil fuels in combination, but in these cases, _CO2 emissions have a negative impact on the environment.

In contrast, Figure 4 shows the temperature of the first liquid held in the internal chamber 32, i.e., the temperature of the first liquid flowing out from the liquid outlet portion 323B, when the driving of the heating device 33 is stopped at night in the temperature control unit 3 of this embodiment. In Figure 4, T _S indicates the timing when the driving of the heating device 33 is stopped.
As can be seen from FIG. 4, in this embodiment, the temperature of the first liquid can be kept at 30° C. or higher for approximately 13 hours even after the driving of the heating device 33 of the temperature control unit 3 is stopped.
In the temperature control unit 3 of this embodiment, the tank 31 is buried underground. This prevents the temperature of the second liquid 314 inside the tank 31 from dropping below the temperature of the ground. That is, even if the heating device 33 is not driven in the morning in Fig. 4, the temperature of the second liquid 314 can be prevented from dropping below the temperature of the ground.
On the other hand, in this embodiment, heating the heating device 33 increases the temperature of the internal chamber 32 itself, in addition to the first liquid, and the heat is transferred through the steel pipe 321 to the second liquid 314 in the tank 31. If the interior of the tank 31 is air, the temperature rise in the tank 31 is small because air has better insulating properties than water. In contrast, in this embodiment, the interior of the tank 31 is filled with the second liquid 314. Furthermore, this second liquid 314 has a higher thermal conductivity than air. Therefore, when the internal chamber 32 is heated, heat from the internal chamber 32 is transferred to the second liquid 314 with high efficiency, allowing heat storage. Furthermore, a heat-retaining portion 315 made of insulating material is provided on the outer periphery of the tank body 311. This suppresses heat release from the tank body 311 into the ground.
As a result, in this embodiment, as shown in FIG. 4, the temperature of the first liquid in the internal chamber 32 can be maintained at 30° C. or higher for a long period of time.

[Cooling mode operation]
The temperature adjustment system 1 of this embodiment can also be used in a cooling mode in which the first liquid introduced from the liquid circulation device 4 is cooled while the driving of the heating device 33 is stopped.
For example, in the above embodiment, the temperature control device is exemplified by a road heater 2 that can be installed on an object such as a road and melts ice and snow on the object. However, an air conditioning device that controls the temperature inside a living space, a greenhouse, or the like may also be used as the temperature control device. In this case, in summer, the air conditioning device causes the first liquid to absorb the heat of air heated by rising air temperature. The first liquid with increased temperature is sent to the temperature control unit 3 by the liquid circulation device 4 and cooled by heat dissipation inside the internal chamber 32. At this time, the heat dissipated to the internal chamber 32 is further dissipated from the steel pipe 321 to the second liquid 314 in the tank 31, thereby suppressing a temperature rise in the internal chamber 32. Furthermore, because the tank 31 is buried underground, a temperature rise is suppressed even in summer. In other words, even if heat from the internal chamber 32 is transferred to the second liquid 314, the heat is dissipated into the ground.
As a result, in the temperature adjustment system 1 of this embodiment, the first liquid can be cooled with low power consumption over a long period of time without driving the heating device 33. In other words, in a conventional device using a heat pump, power is required for compressing and evaporating the refrigerant, which increases power consumption, but in the temperature adjustment system of this embodiment, the first liquid can be cooled simply by sending the first liquid to the temperature control unit 3, thereby significantly reducing power consumption.

[Effects of this embodiment]
The temperature control unit 3 of this embodiment includes a tank 31 that is formed in a hollow box shape, has an internally sealed space, and is buried underground, and an internal chamber 32 that is formed in a hollow box shape and has an internally sealed space and is housed within the tank 31. The temperature control unit 3 also includes a liquid inlet 323A that introduces a first liquid into the internal chamber 32, and a liquid outlet 323B that discharges the first liquid from the internal chamber 32 to the outside. The tank 31 of the temperature control unit 3 is filled with a second liquid 314. That is, the second liquid 314 is filled between the tank 31 and the internal chamber 32.

In this temperature control unit 3, the second liquid effectively suppresses temperature changes in the internal chamber 32, thereby suppressing temperature changes in the first liquid inside the internal chamber 32. In other words, if the tank 31 were filled with air, the air would function as an insulating layer, making it difficult for the tank 31 to store heat from the internal chamber 32. However, in this embodiment, the tank 31 is filled with the second liquid, which has a higher heat conductivity than air. As a result, when the internal chamber 32 is heated by a heating device 33 or the like, that heat is transferred to and stored in the second liquid. This suppresses temperature drops in the internal chamber 32 and the first liquid. Therefore, the temperature of the first liquid can be maintained within a constant temperature range for a long period of time without heating it, thereby saving energy.

Furthermore, when the internal chamber 32 is not heated, the heat of the first liquid introduced into the internal chamber 32 is dissipated into the internal chamber 32. Furthermore, because the tank 31 is buried underground, when no heat is stored in the second liquid, the temperature of the second liquid is approximately the same as the temperature of the ground. Therefore, the heat dissipated from the first liquid to the internal chamber 32 is transferred to the second liquid in the tank 31, thereby effectively reducing the heat in the internal chamber 32.

In the temperature control unit 3 of this embodiment, a heating device 33 is provided inside the internal chamber 32 .
This makes it possible to heat the first liquid in the internal chamber 32. Furthermore, as described above, by heating the internal chamber 32 with the heating device 33, the heat is transferred to the second liquid and stored in the tank 31. This makes it possible to maintain the temperature of the internal chamber 32 and the first liquid inside the internal chamber 32 within a certain range for a long period of time, even if the driving of the heating device 33 is stopped.

In the temperature control unit 3 of this embodiment, the heating device 33 is formed in an elongated shape, and is provided with a liquid spiral heating section 332 along its outer circumferential surface, through which the first liquid flows.
This allows the first liquid introduced into the temperature control unit 3 to be heated efficiently.

The temperature control unit 3 of this embodiment is further provided with a heat insulating section 315 that covers the outer surface of the tank 31 .
This prevents the heat stored in the second liquid in the tank 31 from escaping to the outside, and allows the temperature of the second liquid inside the tank 31 to be maintained for a long period of time.

[Modification]
The present invention is not limited to the above-described embodiments, and the present invention includes configurations obtained by modifications, improvements, and appropriate combinations of the embodiments within the scope that can achieve the object of the present invention.
(Variation 1)
For example, in the above embodiment, the road heater 2 is used as the temperature adjustment device, but the present invention is not limited to this. As described above, the temperature adjustment device may be, for example, an air conditioning device that adjusts the temperature of a space such as a living space or a greenhouse.

(Variation 2)
In the above embodiment, the temperature control unit 3 is configured such that the heating device 33 is provided inside the steel pipe 321 of the internal chamber 32, but the heating device 33 may not be provided.
FIG. 5 is a diagram showing a schematic configuration of a temperature adjustment system 1A according to the second modification.
For example, as shown in FIG. 5, a water heater 7 for heating the first liquid may be connected to the temperature control unit 3A.
The water heater 7 heats the first liquid to a desired temperature and sends it to the temperature control unit 3 A. The first liquid heated by the water heater 7 may be, for example, tap water supplied from a water pipe, or may be water returned from a temperature control device such as the road heater 2 in the above-described embodiment, or antifreeze liquid.

5, the first liquid is heated by the water heater 7, and therefore the heating device 33 is not provided inside the internal chamber 32. In this case, the liquid spiral heating section 332 is not provided, and the internal chamber 32 is used as a water storage chamber for storing the first liquid.
That is, the first liquid introduced from the liquid introduction portion 323A is poured directly into and stored inside the steel pipe 321. When discharging the first liquid from the internal chamber 32, for example, the first liquid is pumped up and sent out using the pump 4A.

With this configuration, the same effects as those of the above embodiment can be achieved. That is, when the first liquid heated by the water heater 7 is introduced into the internal chamber 32, the internal chamber 32 is heated, and the heat is transferred to the second liquid in the tank 31 and stored therein. Furthermore, because the tank 31 is covered with the heat-retaining section 315, heat leakage to the outside of the tank 31 can be suppressed, and a drop in the temperature of the first liquid can be suppressed.

(Variation 3)
In the above-described modified example 2, the heating device 33 and the spiral liquid heating section 332 are not provided inside the internal chamber 32, and the internal chamber 32 is used as a water storage chamber. In contrast to this, in the modified example 2, the heating device 33 as described in the above embodiment may be provided in the internal chamber 32. In other words, the water heater 7 may be provided, and the heating device 33 such as a sheath heater may also be provided inside the internal chamber 32. In this case, when the temperature of the first liquid sent from the water heater 7 and stored in the internal chamber 32 falls below a certain level, the first liquid in the internal chamber 32 can be heated by the heating device 33.

(Variation 4)
In the above embodiment, in order to bury the temperature control unit 3 at a depth of 2 to 3 m underground, an installation chamber 61 is provided and the temperature control unit 3 is buried at the bottom of the installation chamber 61, but this is not limiting. The installation chamber 61 does not have to be provided, and for example, a configuration may be adopted in which a hole is dug in the ground and the temperature control unit 3 is inserted into the hole and buried.

1...Temperature control system, 2...Load heater (temperature control device), 3...Temperature control unit, 5...Controller, 31...Tank, 32...Internal chamber, 33...Heating device, 4...Liquid circulation device, 311...Tank body, 312...Tank lid portion, 314...Second liquid, 321...Steel pipe, 322...Second lid portion, 323...Connector portion, 323A...Liquid inlet portion, 323B...Liquid outlet portion, 332...Liquid spiral heating portion.

Claims (2)

A tank formed in a hollow box shape with an enclosed space inside and buried underground;
an internal chamber that is housed in the tank and formed in a hollow box shape, the internal chamber being a sealed space;
a heating device housed in the internal chamber, formed in an elongated shape, for heating the first liquid;
a liquid introduction portion that introduces a first liquid into the internal chamber;
a liquid outlet portion that discharges the first liquid from the interior of the internal chamber to the outside;
A temperature control unit comprising: a liquid spiral heating section having one end connected to the liquid inlet section and the other end connected to the liquid outlet section, arranged spirally on the outer periphery of the heating device, and through which the first liquid flows; and a second liquid filled between the tank and the internal chamber. The temperature control unit of claim 1, further comprising a heat-retaining section that covers the outer periphery of the tank.