Patent ID: 12253422

DESCRIPTION OF EMBODIMENTS

Hereinafter, an embodiment according to the present invention will be described with reference to the drawings, but the present invention is not limited thereto. Components of the embodiments described below can be appropriately combined. Further, some components may not be used.

First Embodiment

<State Estimation System>

FIG.1is a block diagram illustrating a state estimation system1according to a first embodiment. The state estimation system1estimates a state of an object such as a device M (seeFIG.2) installed in a construction machine or factory equipment, for example. As the state of the object, for example, a maintenance timing such as whether or not the object is in a state that maintenance is performed is estimated. The state of the object may be estimated stepwise according to the degree of deterioration of the object, for example. The device M is, for example, a device that generates heat during operation, including a motor or a gear. As illustrated inFIG.1, the state estimation system1includes a thermoelectric generation device2and a management computer100existing outside the thermoelectric generation device2.

<Thermoelectric Generation Device>

FIG.2is a sectional view illustrating the thermoelectric generation device2. The thermoelectric generation device2is disposed in, for example, the device M disposed in a construction machine or factory equipment. The thermoelectric generation device2detects a temperature of the device M, and transmits a signal indicating the detected temperature to the outside by a radio wave. The device M functions as a heat source of the thermoelectric generation device2.

As illustrated inFIG.2, the thermoelectric generation device2includes a heat reception plate3, a heat sink4, a wall part5, a heat transfer member6, a thermoelectric generation module7, a first temperature sensor8, a second temperature sensor9, a microcomputer10, a capacitor (power storage unit)21, a transmitter (transmission unit)22(seeFIG.1), and a substrate31. The thermoelectric generation device2functions as a thermal load detection unit200that detects a thermal load of the device M together with a temperature data acquisition unit102and a thermal load calculation unit103of the management computer100described later. In the present embodiment, the thermal load detection unit200detects an integrated amount of a temperature difference ΔT between the temperature of the device M and a temperature around the device M as a thermal load.

The heat reception plate3is disposed in the device M. The heat reception plate3is a plate-shaped member. The heat reception plate3is formed of, for example, a metal material containing aluminum or copper. The heat reception plate3receives heat from the device M. Heat of the heat reception plate3is conducted to the thermoelectric generation module7via the heat transfer member6.

The heat sink4faces the heat reception plate3in a Z-axis direction and is disposed apart from the heat reception plate3. The heat sink4is a plate-like member. The heat sink4is formed of, for example, a metal material containing aluminum or copper. The heat sink4receives heat from the thermoelectric generation module7. Heat of the heat sink4is radiated to an atmospheric space around the thermoelectric generation device2.

The wall part5has a rectangular tube shape as viewed in the Z axis direction. The wall part5is disposed to surround the heat reception plate3and the heat sink4. The wall part5, the heat reception plate3, and the heat sink4form a box shape having a space therein. The wall part5is formed of a synthetic resin material having heat insulation properties and radio wave transparency.

A seal member51is disposed at a connection portion between a peripheral edge portion of the heat reception plate3and an end portion on a −Z side of the wall part5. A seal member52is disposed at a connection portion between a peripheral edge portion of the heat sink4and an end portion on a +Z side of the wall part5. The seal member51and the seal member52include, for example, an O-ring. The seal member51and the seal member52seal the thermoelectric generation device2. Thus, entry of foreign matter into the thermoelectric generation device2is restricted.

The heat transfer member6is erected from the heat reception plate3toward the +Z side. The heat transfer member6connects the heat reception plate3and the thermoelectric generation module7. The heat transfer member6conducts heat of the heat reception plate3to the thermoelectric generation module7. The heat transfer member6is formed of, for example, a metal material containing aluminum or copper. The heat transfer member6has a columnar shape elongated in the Z-axis direction.

The thermoelectric generation module7generates electric power using the Seebeck effect. The thermoelectric generation module7is disposed on the heat sink4. When an end face71on the −Z side of the thermoelectric generation module7is heated by the heat source, a temperature difference is generated between −Z-side end face71and an end face72on the +Z side of the thermoelectric generation module7. The thermoelectric generation module7generates electric power by a temperature difference generated between the end face71and the end face72. The thermoelectric generation module7may be disposed on the heat reception plate3. A detailed configuration of the thermoelectric generation module7will be described later.

The first temperature sensor8is disposed on the heat sink4. The first temperature sensor8detects a temperature around the device M. The first temperature sensor8is driven by electric power generated by the thermoelectric generation module7.

The second temperature sensor9is disposed on the heat reception plate3. The second temperature sensor9detects the temperature of the device M. The second temperature sensor9is driven by electric power generated by the thermoelectric generation module7.

The capacitor21stores electric charge generated from the thermoelectric generation module7. When the stored electric power exceeds a predetermined amount, the capacitor21drives the first temperature sensor8and the second temperature sensor9, the microcomputer10, and the transmitter22.

The transmitter22wirelessly transmits a transmission signal based on detection data of the first temperature sensor8and the second temperature sensor9. The transmitter22is driven by electric power generated by the thermoelectric generation module7. The transmitter22is driven by the discharge from the capacitor21. The transmitter22is disposed on the substrate31.

The transmitter22transmits a transmission signal generated by the processing unit12of the microcomputer10and based on the detection data of the first temperature sensor8and the second temperature sensor9to the management computer100at every predetermined time interval. The predetermined time is, for example, approximately several 10 seconds.

Alternatively, the transmitter22may transmit the transmission signal based on the detection data to the management computer100every time the electric power stored in the capacitor21exceeds a predetermined amount.

The substrate31includes a control substrate. The substrate31is disposed between the heat reception plate3and the heat sink4. The substrate31is connected to the heat sink4via the support member31B.

<Microcomputer>

Returning toFIG.1, the microcomputer10controls the thermoelectric generation device2. The microcomputer10is driven by electric power generated by the thermoelectric generation module7. The microcomputer10includes a detection data acquisition unit11and a processing unit12. The microcomputer10is disposed on the substrate31.

The detection data acquisition unit11acquires detection data of the first temperature sensor8and the second temperature sensor9. The detection data of the first temperature sensor8and the second temperature sensor9acquired by the detection data acquisition unit11is processed by the processing unit12and transmitted to the management computer100by the transmitter22.

The processing unit12generates a transmission signal to be transmitted to the management computer100on the basis of the detection data acquired by the detection data acquisition unit11. In the present embodiment, the processing unit12generates a transmission signal indicating a temperature difference ΔT between a temperature of the heat reception plate3detected by the second temperature sensor9and a temperature of the heat sink4detected by the first temperature sensor8on the basis of the detection data acquired by the detection data acquisition unit11. The generated transmission signal is transmitted to the management computer100via the transmitter22.

ΔT is expressed by following Equation 1. Th is the temperature of the heat reception plate3of the thermoelectric generation module7detected by the second temperature sensor9. Tc is the temperature of the heat sink4detected by the first temperature sensor8.
ΔT=Th−Tc(1)
<Operation of Thermoelectric Generation Device>

An example of operation of the thermoelectric generation device2configured as described above will be described. The thermoelectric generation device2operates while the state estimation system1is activated.

When the device M is driven, the device M generates heat. The heat of the device M is conducted to the thermoelectric generation module7via the heat reception plate3and the heat transfer member6. The thermoelectric generation module7that has received the heat generates power by the temperature difference generated between the end face71and the end face72. The electric power generated by the thermoelectric generation module7drives the first temperature sensor8, the second temperature sensor9, the microcomputer10, and the transmitter22. The first temperature sensor8detects a temperature around the device M. The second temperature sensor9detects the temperature of the device M. The microcomputer10causes the detection data acquisition unit11to acquire detection data from the first temperature sensor8and the second temperature sensor9. The microcomputer10causes the processing unit12to generate a transmission signal indicating the temperature difference ΔT based on the detection data of the first temperature sensor8and the second temperature sensor9. The transmitter22transmits the transmission signal indicating the temperature difference ΔT to the management computer100.

<Management Computer>

The management computer100is disposed outside the thermoelectric generation device2, for example, in a management center where a state of a construction machine or factory equipment including a state of the device M is managed. The management computer100includes a reception unit101, a temperature data acquisition unit102, a thermal load calculation unit103, and an estimation unit104. The temperature data acquisition unit102and the thermal load calculation unit103of the management computer100function as the thermal load detection unit200together with the thermoelectric generation device2.

The reception unit101wirelessly receives data from the thermoelectric generation device2.

The temperature data acquisition unit102acquires temperature data regarding the device M from the thermoelectric generation device2. More specifically, the temperature data acquisition unit102acquires the transmission signal based on the detection data of the first temperature sensor8and the second temperature sensor9from the transmitter22of the thermoelectric generation device2via the reception unit101.

The thermal load calculation unit103calculates the thermal load of the device M. In the present embodiment, the thermal load calculation unit103calculates the thermal load of the device M from a transmission signal based on the detection data indicating the temperature of the device M acquired by the temperature data acquisition unit102. More specifically, the thermal load calculation unit103calculates the integrated amount of the temperature difference ΔT as the thermal load of the device M on the basis of the transmission signal indicating the temperature difference ΔT between the temperature of the heat reception plate3detected by the second temperature sensor9of the thermoelectric generation device2and the temperature of the heat sink4detected by the first temperature sensor8, which are acquired by the temperature data acquisition unit102.

The thermal load calculation unit103may calculate the integrated amount of the temperature difference ΔT by integrating output values transmitted from the thermoelectric generation device2, and may use the integrated amount as the thermal load of the device M.

By integrating the temperature difference ΔT, not a simple operating time of the device M but an operating time in consideration of an operation load of the device M is calculated as a thermal load of the device M.

FIG.3is a diagram describing a correlation between an output of the device M and temperatures of the device M and the surroundings.FIG.3(a)illustrates the output from a start to a stop of the device M. As illustrated inFIG.3(a), the device M starts at time T0, has a constant output from time T1to time T2, starts a stop operation at time T2, and stops at time T3. InFIG.3(b), the temperature of the device M as a heat source is indicated by a thick solid line, and the temperature difference ΔT between the temperature of the device M and the temperature around the device M is indicated by a solid line. The area of a region surrounded by the solid line indicating the temperature difference ΔT and a horizontal axis indicates the integrated amount of the temperature difference ΔT. As illustrated inFIG.3(b), the temperature of the device M changes according to the output of the device M, in other words, the operation load of the device M. The temperature difference ΔT changes according to the temperature of the device M.FIG.3(c)illustrates an output of the transmission signal indicating the temperature difference ΔT output from the thermoelectric generation device2. As illustrated inFIG.3(c), the transmission signal indicating the temperature difference ΔT, which is the output from the thermoelectric generation device2, is transmitted at predetermined time intervals.

The estimation unit104estimates the state of the device M on the basis of the thermal load of the device M detected by the thermal load detection unit200. More specifically, the estimation unit104estimates the state of the device M on the basis of the thermal load of the device M calculated by the thermal load calculation unit103. In the present embodiment, the estimation unit104estimates the state of the device M on the basis of the integrated amount of the temperature difference ΔT as the thermal load calculated by the thermal load calculation unit103. The state of the device M may be estimated as good or bad, or the state may be estimated in stages.

For example, in a case where the integrated amount of the temperature difference ΔT is equal to or more than a threshold, the estimation unit104estimates that the state of the device M is “defective” requiring an inspection, and in a case where the integrated amount of the temperature difference ΔT is less than the threshold, the estimation unit104estimates that the state of the device M is “good” not requiring the inspection.

For example, the estimation unit104estimates the state of the device M as “caution” that does not require inspection when the integrated amount of the temperature difference ΔT is equal to or larger than a first threshold, estimates the state of the device M as “inspection required” that requires the inspection when the integrated amount of the temperature difference ΔT is equal to or larger than a second threshold larger than the first threshold, and estimates the state of the device M as “replacement required” that requires replacement when the integrated amount of the temperature difference ΔT is equal to or larger than a third threshold larger than the second threshold. When the integrated amount of the temperature difference ΔT is less than the first threshold, the estimation unit104estimates that the state of the device M is “good” in which no inspection is required.

Furthermore, the estimation unit104may estimate the state of the device M on the basis of the operating time of the device M in addition to the integrated amount of the temperature difference ΔT. For example, in a case where the integrated amount of the temperature difference ΔT is equal to or more than the threshold and the operating time of the device M is equal to or more than an operable time, the estimation unit104may estimate that the state of the device M is “defective” that requires inspection.

FIG.4is a diagram describing a correlation between the temperature difference ΔT and the operable time of the device M.FIG.4illustrates that the larger the temperature difference ΔT, the shorter the operable time of the device M. This is because the operation load of the device M increases as the temperature difference ΔT increases.

<Processing of Management Computer>

Next, an example of processing of the management computer100will be described with reference toFIG.5.FIG.5is a flowchart illustrating an example of processing in the management computer100of the state estimation system1according to the first embodiment. The management computer100operates while the state estimation system1is activated.

In the management computer100, the temperature data acquisition unit102acquires temperature data via the reception unit101(step S11). More specifically, the management computer100causes the temperature data acquisition unit102to acquire a transmission signal based on the detection data of the first temperature sensor8and the second temperature sensor9from the thermoelectric generation device2via the reception unit101. In the present embodiment, the signal indicating the temperature difference ΔT between the temperature of the heat reception plate3detected by the second temperature sensor9and the temperature of the heat sink4detected by the first temperature sensor8is acquired as the transmission signal. The management computer100proceeds to step S12.

The management computer100calculates, by the thermal load calculation unit103, the integrated amount of the temperature difference ΔT as the thermal load of the device M (step S12). More specifically, by the thermal load calculation unit103, the integrated amount of the temperature difference ΔT is calculated as the thermal load of the device M on the basis of the transmission signal indicating the temperature difference ΔT between the temperature of the heat reception plate3detected by the second temperature sensor9and the temperature of the heat sink4detected by the first temperature sensor8. The management computer100proceeds to step S13.

The management computer100causes the estimation unit104to estimate the state of the device M on the basis of the integrated amount of the temperature difference ΔT calculated by the thermal load calculation unit103(step S13).

<Effects>

As described above, the present embodiment includes the first temperature sensor8and the second temperature sensor9of the thermoelectric generation device2that detect the temperature of the device M, and the thermal load calculation unit103of the management computer100, which function as the thermal load detection unit200. The present embodiment includes the estimation unit104that estimates the state of the device M on the basis of the thermal load of the device M calculated by the thermal load calculation unit103. According to the present embodiment, the state of the device M can be appropriately estimated on the basis of the thermal load of the device M. According to the present embodiment, a maintenance timing can be appropriately estimated for each device M.

In the present embodiment, the thermal load calculation unit103calculates, as a thermal load, an integrated amount of a temperature difference ΔT between the temperature of the heat reception plate3detected by the second temperature sensor9and the temperature of the heat sink4detected by the first temperature sensor8. According to the present embodiment, it is possible to appropriately estimate the state of the device M not by the simple operating time of the device M but by the operating time in consideration of the operation load of the device M.

In the present embodiment, for example, when a rapid temperature change occurs in the device M, the temperature difference ΔT also changes rapidly. Thus, according to the present embodiment, even when a rapid temperature change occurs in the device M, the state of the device M can be appropriately estimated. In the present embodiment, the state of the device M can be appropriately estimated according to the state of the load of the device M.

In the present embodiment, the thermoelectric generation device2disposed in the device M detects the temperature in the device M and transmits detected detection data. In the present embodiment, the thermoelectric generation module7generates electric power by heat generated by the device M. In the present embodiment, a temperature sensor driven by the thermoelectric generation module7detects a temperature. Further, in the present embodiment, the transmitter22driven by the thermoelectric generation module7wirelessly transmits a transmission signal based on detection data of the temperature sensor. According to the present embodiment, in the detection of the temperature in the device M and the transmission of the detected detection data, a power source and a battery can be made unnecessary, and a cable for transmitting the detection data can also be made unnecessary. Unlike the battery-type temperature sensor, the present embodiment can appropriately acquire the detection data without increasing intervals of temperature detection or decreasing a transmission frequency of the detection data in order to secure the usable time of the battery. Further, according to the present embodiment, the installation location is not limited, and it is possible to be applied to various devices M at various installation locations.

In the present embodiment, when the thermoelectric generation device2is disposed in the device M, a transmission signal based on the detection data of the first temperature sensor8and the second temperature sensor9is transmitted to the management computer100. In the present embodiment, the management computer100can appropriately estimate the state of the device M on the basis of the received detection data.

Further, in a case where a plurality of devices M exists, the management computer100can estimate states of the plurality of devices M only by disposing the thermoelectric generation device2in each of the plurality of devices M.

Second Embodiment

FIG.6is a flowchart illustrating an example of processing in the management computer100of the state estimation system1according to the second embodiment. In the following description, the same or equivalent components as those of the above-described embodiment are denoted by the same reference numerals, and the description thereof will be simplified or omitted. The second embodiment is different from the first embodiment in processing in the thermal load calculation unit103and the estimation unit104of the management computer100. In the present embodiment, the thermal load detection unit200detects, as a thermal load, an amount of change per unit time of the temperature difference ΔT between the temperature of the device M and the temperature around the device M.

<Management Computer>

The thermal load calculation unit103calculates, as a thermal load, an amount of change per unit time of the temperature difference ΔT between the temperature of the heat reception plate3detected by the second temperature sensor9and the temperature of the heat sink4detected by the first temperature sensor8, in other words, a gradient of the temperature difference ΔT.

The thermal load calculation unit103may calculate the gradient of the temperature difference ΔT on the basis of output values transmitted from the thermoelectric generation device2. The difference between the output values plotted inFIG.3(c)is the gradient of the temperature difference ΔT.

The estimation unit104estimates the state of the device M on the basis of the amount of change per unit time of the temperature difference ΔT.

TABLE 1Environmental temperature and ΔT Unit: ° C.MorningAfternoonEveningTa203530Tc223732Th304540ΔT888

The “robustness” of the temperature difference ΔT will be described with reference to Table 1. Table 1 presents environmental temperatures and the temperature difference ΔT. Ta is an environmental temperature indicating a temperature around a construction machine or factory equipment in which the device M is installed. Tc is the temperature of the heat sink4detected by the first temperature sensor8. Th is the temperature of the heat reception plate3of the thermoelectric generation module7detected by the second temperature sensor9. The environmental temperature Ta is not always constant, and the temperature changes in one day. Each of Tc and Th changes in temperature in accordance with a change in output of the device M in addition to a change in temperature of the environmental temperature Ta. In the example illustrated in Table 1, the temperature difference ΔT, which is a difference between Th and Tc, is always constant at 8° C. As described above, the temperature difference ΔT, which is the difference between Th and Tc, has “robustness” to become constant regardless of the ambient temperature.

When the output of the device M increases or decreases and only the device M changes in temperature, the temperature difference ΔT changes and the gradient of the temperature difference ΔT changes. When a change occurs in the temperature difference ΔT and a change occurs in the gradient of the temperature difference ΔT beyond an allowable range, it is estimated that a problem occurs in the device M and the entire system including the device M and appears as a temperature change of the device M.

For example, when the amount of change per unit time of the temperature difference ΔT is equal to or greater than a threshold, the estimation unit estimates the state of the device M to be “defective (there is a rapid temperature change)”, and when the amount of change per unit time of the temperature difference ΔT is less than the threshold, the estimation unit104estimates the state of the device M to be “good”.

<Processing of Management Computer>

Next, an example of processing of the management computer100will be described with reference toFIG.6. In step S21, processing similar to that in step S11of the flowchart illustrated inFIG.5is performed.

The management computer100calculates, by the thermal load calculation unit103, the amount of change per unit time of the temperature difference ΔT as the thermal load of the device M (step S22). More specifically, by the thermal load calculation unit103, the amount of change per unit time of the temperature difference ΔT is calculated as the thermal load of the device M on the basis of the transmission signal indicating the temperature difference ΔT between the temperature of the heat reception plate3detected by the second temperature sensor9and the temperature of the heat sink4detected by the first temperature sensor8. The management computer100proceeds to step S23.

The management computer100causes the estimation unit104to estimate the state of the device M on the basis of the amount of change per unit time of the temperature difference ΔT calculated by the thermal load calculation unit103(step S23).

<Effects>

As described above, in the present embodiment, the amount of change per unit time of the temperature difference ΔT between the temperature of the heat reception plate3detected by the second temperature sensor9and the temperature of the heat sink4detected by the first temperature sensor8is calculated as a thermal load. According to the present embodiment, the state of the device M can be appropriately estimated on the basis of the amount of change per unit time of the temperature difference ΔT. According to the present embodiment, when a problem occurs in the device M and the entire system including the device M and appears as a temperature change of the device M, the state of the device M can be appropriately estimated. As described above, according to the present embodiment, a sudden change in the device M and the entire system including and the device M can be considered in the estimation of the state of the device M.

Third Embodiment

FIG.7is a block diagram illustrating a state estimation system1A according to a third embodiment.FIG.8is a flowchart illustrating an example of processing in a management computer100A of the state estimation system1A according to the third embodiment. The third embodiment is different from the first embodiment in configurations of a thermoelectric generation device2A and the management computer100A.

<Thermoelectric Generation Device>

The thermoelectric generation device2A includes a heat reception plate3, a heat sink4, a wall part5, a heat transfer member6, a thermoelectric generation module7, a microcomputer10A, a capacitor21, a transmitter22, and a substrate31. The thermoelectric generation module7, the capacitor21, and the transmitter22of the thermoelectric generation device2A function as a thermal load detection unit200A together with a reception unit101and a thermal load calculation unit103A of a management computer100A described later.

The microcomputer10A has a transmission control unit13A. The transmission control unit13A generates a transmission signal transmitted from the transmitter22when electric power stored in the capacitor21exceeds a predetermined amount to drive the transmitter22. The transmission signal may be the same signal every time or may be a signal different for each transmission. For example, the transmission signal may include a current time, the number of transmissions, information for identifying the thermoelectric generation device2A, and the like.

<Management Computer>

The management computer100A includes a reception unit101, a thermal load calculation unit103A, and an estimation unit104A.

The thermal load calculation unit103A calculates a transmission frequency, which is the number of times of transmission per unit time of the transmitter22, as the thermal load of the device M on the basis of the number of times the reception unit101receives data from the transmitter22of the thermoelectric generation device2A.

As described above, the thermoelectric generation module7generates electric power by generation of the temperature difference ΔT between the heat reception plate3and the heat sink4. The capacitor21stores the electric charge generated from the thermoelectric generation module7, and drives the transmitter22when the stored electric power exceeds a predetermined amount. Thus, the transmission frequency of the transmitter22increases as the thermal load of the device M increases. That is, when the thermal load of the device M changes, the transmission frequency changes. Further, a high transmission frequency indicates that the temperature difference ΔT is large. In this manner, the transmission frequency changes according to the temperature difference ΔT.

The estimation unit104A estimates the state of the device M on the basis of the transmission frequency of the transmitter22of the thermoelectric generation device2A calculated by the thermal load calculation unit103A.

For example, the estimation unit104A estimates the state of the device M to be “defective (with a rapid temperature change)” when the transmission frequency of the transmitter22is equal to or more than the threshold, and estimates the state of the device M to be “good” when the transmission frequency of the transmitter22is less than the threshold.

<Processing of Management Computer>

Next, an example of processing of the management computer100A will be described with reference toFIG.8.

The management computer100A receives data from the thermoelectric generation device2A by the reception unit101(Step S31). The management computer100A proceeds to step S32.

The management computer100A calculates, by the thermal load calculation unit103A, the transmission frequency from the transmitter22of the thermoelectric generation device2A as the thermal load of the device M (step S32). More specifically, by the thermal load calculation unit103A, the frequency at which the reception unit101receives data from the transmitter22of the thermoelectric generation device2A, in other words, the transmission frequency at which the transmitter22of the thermoelectric generation device2A transmits data is calculated as the thermal load of the device M. The management computer100A proceeds to step S33.

The management computer100A estimates the state of the device M by the estimation unit104A on the basis of the transmission frequency at which the transmitter22of the thermoelectric generation device2A has transmitted the data, which is calculated by the thermal load calculation unit103A (step S33).

<Effects>

As described above, the present embodiment includes the thermoelectric generation module7, the capacitor21that stores electric charge generated from the thermoelectric generation module7, the transmitter22that is driven by discharge from the capacitor21, and the thermal load calculation unit103A that calculates a transmission frequency of the transmitter22as the thermal load of the device M, which function as the thermal load detection unit200A. The estimation unit104A estimates the state of the device M on the basis of the transmission frequency of the transmitter22calculated by the thermal load calculation unit103A. According to the present embodiment, the state of the device M can be appropriately estimated on the basis of the transmission frequency of the transmitter22. According to the present embodiment, a rapid change in the device M and the entire system including the device M can be considered in estimation of the state of the device M.

Modification Example

In each of the above-described embodiments, the microcomputer10may have the function of the management computer100.

In the above-described first and second embodiments, the thermoelectric generation device2is described to detect the temperature of the device M and transmit the detected detection data, but is not limited thereto. A temperature sensor that is driven by electric power supplied from a power source or a battery, and a transmitter that is driven by electric power supplied from the power source or the battery and transmits detection data to the management computer100in a wired manner may be used.

In each of the above-described embodiments, the processing unit12of the thermoelectric generation device2is described to generate a transmission signal indicating the temperature difference ΔT between the temperature of the heat reception plate3detected by the second temperature sensor9and the temperature of the heat sink4detected by the first temperature sensor8, and transmit the transmission signal indicating the temperature difference ΔT from the thermoelectric generation device2to the management computer100, but is not limited thereto. The processing unit12of the thermoelectric generation device2may generate a transmission signal indicating each piece of detection data of the first temperature sensor8and the second temperature sensor9and transmit the transmission signal to the management computer100, and the temperature data acquisition unit102of the management computer100may calculate the temperature difference ΔT from each piece of acquired detection data.