Heat conductance measuring method and heat conductance measuring system

Abstract

To grasp the heat conductance of a heat source and contribute to the effective utilization of unused heat energy.SOLUTION: The other end of a heat conduction path having a cooling source at one end is connected to a heat source which is the object to be measured (S10). A heater element controllable so as to cause a generated heat amount to change by adding fluctuating heating energy is installed in the heat conduction path, the temperature in the heat conduction path is measured, and a first temperature when affected by heat generation by the heater element and a second temperature when unaffected are acquired (S30, S50). On the basis of the difference between the first and the second temperatures (S60) and the heating energy at the time the first temperature is measured, the heat conductance of the heat source is calculated (S80). Thus, since the heat conductance of the heat source can be calculated without the need for grasping the specific heat or mass or the like of the heat source, it is possible to contribute to effective utilization of the unused heat energy that the heat source possesses.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a thermal conductance measurement method and a thermal conductance measurement system for measuring the thermal conductance of a heat source. [Background technology]

[0002] For example, thermal energy is discarded as exhaust heat in industrial plants that handle thermal energy, various devices that use heat sources, combustion devices, internal combustion engines, incinerators, hot spring water flow paths, exhaust ducts, chimneys, steam pipes, etc. Research into the effective use of such unused thermal energy has been conducted for some time (see, for example, Patent Documents 1 and 2), but a large amount of thermal energy is still discharged into the atmosphere, which is one of the causes of global warming and other issues. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5299324 [Patent Document 2] JP 2014-174027 A Summary of the Invention [Problem to be solved by the invention]

[0004] Here, in order to effectively utilize unused thermal energy from a heat source, it is effective to perform a simulation approach based on basic information such as the heat receiving area and amount of heat received per unit area of ​​the high-temperature heat source to which a heat exchanger or the like is attached, the heat dissipation on the cold heat source side, and information on the heat exhaust system. The most important factor in such a simulation is the thermal conductance at the heat receiving point, which represents the thermal resistance of the heat source, and is necessary to measure and estimate in advance the amount of heat received that flows in through a heat exchanger or the like. However, the importance of thermal conductance in the effective utilization of unused thermal energy has been overlooked. The present invention has been made in consideration of the above problems, and an object of the present invention is to grasp the thermal conductance of a heat source and contribute to the effective utilization of unused thermal energy. [Means for solving the problem]

[0005] (Modes of the Invention) The following aspects of the invention are illustrative of the configuration of the present invention, and are described in terms of items to facilitate understanding of the various configurations of the present invention. Each item does not limit the technical scope of the present invention. Therefore, while taking into consideration the best mode for carrying out the invention, even if some of the components of each item are replaced or deleted, or other components are added, they may be included in the technical scope of the present invention.

[0006] (1) A method for measuring the thermal conductance of a heat source, comprising: connecting one end of a heat conduction path having a cooling source at the other end to the heat source; placing a heating element in the heat conduction path that can be controlled so that the amount of heat generated varies when a varying heating energy is applied; measuring the temperature in the heat conduction path to obtain a first temperature when the heat conduction path is affected by the heat generated by the heating element and a second temperature when the heat conduction path is not affected; and calculating the thermal conductance of the heat source based on the difference between the first temperature and the second temperature and the heating energy when the first temperature was measured.

[0007] The thermal conductance measurement method described in this section measures the thermal conductance of a heat source having unused thermal energy that is being discharged. Specifically, a heat conduction path having a cooling source at one end is connected to the heat source at the other end, thereby shunting heat so that it flows from the heat source to the cooling source. The heat conduction path used in this case is formed of a material whose characteristics such as thermal conductivity are known in advance. In addition, a heating element is installed in the heat conduction path, i.e., between one end of the heat conduction path where the cooling source is installed and the other end of the heat conduction path connected to the heat source. The heating element to be installed is one that can be controlled so that the amount of heat generated varies when a varying heating energy is applied. Here, the heat conduction path on which the heating element is installed in advance may be connected to the heat source.

[0008] Furthermore, the temperature in the heat conduction path configured as described above is measured to obtain a first temperature when the heat is generated by the heat generating body and a second temperature when the heat is not generated by the heat generating body. In this case, the first temperature may be a temperature measured in the heat conduction path when the heat generating body is controlled so that the amount of heat generated varies. In contrast, the second temperature may be a temperature calculated from the measurement result of the first temperature so as to eliminate the influence of heat generated by the heat generating body depending on the situation, or may be a temperature measured in the heat conduction path when the heat generating body is not generating heat. Next, the difference between the first temperature and the second temperature obtained as described above is calculated to extract temperature change data that has changed due to the influence of the fluctuating heat generated by the heat generating body. Then, the thermal conductance of the heat source is calculated based on the extracted temperature change data and the heating energy given to the heat generating body when the first temperature was measured.

[0009] Regarding the relationship between heat quantity and temperature, in the range of infinitesimal temperature change without phase change, heat quantity is proportional to temperature with mass and specific heat as constants. For this reason, considering that the addition of heating energy causes no change in mass and specific heat and the temperature rises by the amount of temperature change data, the "product of mass and specific heat" can be expressed as the value obtained by dividing the "amount of heat in a state where it is not receiving heating energy" by the "temperature in a state where it is not receiving heating energy (second temperature)" or the value obtained by dividing the "amount of heat in a state where it is receiving heating energy" by the "temperature in a state where it is receiving heating energy (first temperature)". Furthermore, if radiation and thermal conduction that creates errors are so infinitesimal that they can be ignored, the "product of mass and specific heat" can also be expressed as the value obtained by dividing heating energy by temperature change data.

[0010] In addition, since thermal resistance is the temperature difference between two points divided by the heat flow rate (amount of heat flowing per unit time) flowing between the two points, in the above relationship, it can be expressed as the temperature change data divided by the heating energy. And, considering that this thermal resistance includes all the thermal resistances from the heat source to the heat conduction path, that the thermal conductance can be expressed as the reciprocal of the thermal resistance, and that the heat receiving area of ​​the heat conduction path, it is understood that the thermal conductance per unit area can be calculated from the temperature change data and the heating energy. In this way, the thermal conductance of the heat source can be calculated based on the temperature change data changed by the influence of the heating body and the heating energy given to the heating body at that time, without the need to know the specific heat or mass of the heat source. Since the thermal conductance is understood in this way, it contributes to the effective use of unused thermal energy of the heat source. Moreover, the thermal conductance can be understood even when the information inside the heat source, such as the specific heat, pressure, and density of the physical properties of the heat source, is unknown, or even when the pressure and density of the heat source change over time.

[0011] (2) In the above (1), a Peltier element is used as the heating element, AC power of a predetermined frequency different from a fluctuation frequency of the heat flow from the heat source is applied as the heating energy, data of a frequency component of the predetermined frequency is extracted from a calculation result of a difference between the first temperature and the second temperature, and a thermal conductance of the heat source is calculated based on the extraction result. The thermal conductance measurement method described in this section utilizes a Peltier element as a heating element installed in a heat conduction path. In addition, AC power of a predetermined frequency is applied to the Peltier element as heating energy, thereby fluctuating the amount of heat generated from the Peltier element in an AC manner. The predetermined frequency of the AC power is set to a frequency different from the fluctuating frequency of the heat flow from the heat source to the heat conduction path.

[0012] Then, after calculating the difference between the first temperature when affected by the heat generated by the heating element and the second temperature when not affected by the heat generated by the heating element, data of the frequency component of the above-mentioned predetermined frequency is extracted from the calculation result. The thermal conductance of the heat source is calculated based on the temperature difference data extracted in this way and the AC power applied to the Peltier element. That is, a modulation power of a frequency different from the fluctuation frequency of the heat flow from the heat source is applied to the Peltier element, and data of the frequency component of the modulation frequency is extracted and used to calculate the thermal conductance while eliminating the fluctuation component of the heat flow. This allows the thermal conductance to be calculated more accurately.

[0013] (3) A thermal conductance measurement method according to the above (1) or (2), further comprising, when calculating the thermal conductance of the heat source, calculating a total thermal resistance from the heat source to the heat conduction path based on a difference between the first temperature and the second temperature and the heating energy when the first temperature is measured, and calculating a thermal resistance inside the heat source based on the total thermal resistance. The thermal conductance measurement method described in this section measures the thermal resistance inside the heat source in addition to the thermal conductance of the heat source. As mentioned in the above section (1), the thermal resistance calculated from the temperature change data (the difference between the first temperature and the second temperature) and the heating energy (the heating energy when the first temperature is measured) is the total thermal resistance including all the thermal resistances from the heat source to the heat conduction path. That is, this total thermal resistance includes the thermal resistance inside the heat source, whose information such as specific heat, pressure, and density of physical properties is unknown, the thermal resistance of the heat receiving part of the heat conduction path formed of a material whose characteristics such as thermal conductivity are known, and the thermal resistance of the heat conducting part of the heat conduction path. Therefore, the thermal resistance inside the heat source is calculated based on the total thermal resistance as described above and the thermal resistance of the heat conduction path, which is calculated because it is formed of a material whose thermal conductivity is known. As a result, even if the information inside the heat source is unknown, the thermal resistance can be calculated as the information inside the heat source from the calculated total thermal resistance and the known thermal resistance information.

[0014] (4) A system for measuring the thermal conductance of a heat source, comprising: a heat generating element that can be controlled to vary the amount of heat generated, sandwiched between two thermally conductive media made of materials with known thermal conductivity; a thermal conduction modulation unit that is installed so that heat is conducted from the heat source to one of the two thermally conductive media; a cooling source that has a lower temperature than the heat source and is installed so that heat is conducted from the other of the two thermally conductive media; a heat generating element control unit that controls the heat generating element by applying varying heating energy to the heat generating element; a temperature measurement unit that measures the temperature of a temperature measurement point set at a predetermined position on both or either of the two thermally conductive media; and a calculation processing unit that performs calculation processing, wherein the calculation processing unit calculates, from the measurement result of the temperature measurement unit, a difference between a first temperature when the heat generating element is affected and a second temperature when the heat generating element is not affected, and calculates the thermal conductance of the heat source based on the difference and the heating energy when the first temperature is measured.

[0015] The thermal conductance measurement system described in this section measures the thermal conductance on a heat receiving surface per unit area that can be collected from a heat source having unused thermal energy, and includes a thermal conduction modulation unit, a cooling source, a heat generating element control unit, a temperature measurement unit, and a calculation processing unit. The thermal conduction modulation unit has a configuration in which a heat generating element is sandwiched between two heat conducting media, and the heat generating element is controllable so that its heat generation amount varies, and the two heat conducting media are formed of materials with known thermal conductivity. The thermal conduction modulation unit having such a configuration is installed so that heat is conducted from the heat source to be measured to one of the two heat conducting media. The cooling source has a lower temperature than the heat source to be measured, and is installed so that heat is conducted from the other of the two heat conducting media. In other words, the thermal conduction modulation unit and the cooling source are installed as part of a heat conduction path that shunts heat from the heat source so that heat flows from the heat source toward the cooling source.

[0016] The heating element control unit controls the heating element of the thermal conduction modulation unit, and controls the heating element so that the amount of heat generated from the heating element varies by providing the heating element with a varying heating energy. The temperature measurement unit measures the temperature at the temperature measurement point, and the temperature measurement point is set at a predetermined position on both or either of the two thermal conduction media of the thermal conduction modulation unit. The calculation processing unit performs various calculation processes in the system, and performs the following calculations as part of the calculations. That is, the calculation processing unit obtains a first temperature when the temperature is affected by the heat generated by the heating element and a second temperature when the temperature is not affected by the heat generated by the heating element from the measurement results of the temperature measurement point by the temperature measurement unit, as described in the above paragraph (1). Then, the difference between the first and second temperatures is calculated to extract temperature change data that has changed due to the influence of the varying heat generated by the heating element.

[0017] Furthermore, the calculation processing unit calculates the thermal conductance of the heat source to be measured as described in the above paragraph (1) based on the extracted temperature change data and the heating energy given to the heat source by the heat source control unit when the first temperature is measured by the temperature measurement unit. This allows the thermal conductance of the heat receiving surface that can be collected from the heat source to be calculated without the need to know the specific heat or mass of the heat source. Moreover, since the structure is such that heat is diverted from the heat source to be measured via a heat conduction path including a heat conduction modulation unit and a cooling source, and the temperature is measured in the heat conduction modulation unit in the heat conduction path, it is possible to measure heat sources in various environments, including heat sources in which corrosive gases and gas-liquid mixtures with medium density fluctuations flow. Furthermore, there is no need to consider durability such as corrosion, and durability and reliability are significantly improved.

[0018] (5) In the thermal conductance measurement system according to the above paragraph (4), the heating element is a Peltier element, the heating element control unit applies AC power of a predetermined frequency different from a fluctuation frequency of the heat flow from the heat source as the heating energy, and the calculation processing unit extracts data of a frequency component of the predetermined frequency from a calculation result of a difference between the first temperature and the second temperature, and calculates a thermal conductance of the heat source based on the extraction result. In the thermal conductance measurement system described in this section, the heat generating element of the thermal conduction modulation unit is a Peltier element, and the heating energy provided to this Peltier element by the heat generating element control unit is AC power of a predetermined frequency, so that the amount of heat generated from the Peltier element fluctuates in an AC manner. The predetermined frequency of the AC power at this time is set to a frequency different from the fluctuating frequency of the heat flow flowing from the heat source to the thermal conduction modulation unit, etc.

[0019] Then, the calculation processing unit calculates the difference between the first temperature when the temperature is affected by the heat generated by the heat generating element and the second temperature when the temperature is not affected by the heat generated by the heat generating element, and then extracts data of the frequency component of the above-mentioned predetermined frequency from the calculation result. Furthermore, the calculation processing unit calculates the thermal conductance of the heat source based on the temperature difference data extracted in this way and the AC power applied to the Peltier element from the heat generating element control unit. That is, as mentioned in the above item (2), a modulation power of a frequency different from the fluctuation frequency of the heat flow from the heat source is applied to the Peltier element, and data of the frequency component of the modulation frequency is extracted and used to calculate the thermal conductance while eliminating the fluctuation component of the heat flow. This allows the thermal conductance to be calculated with greater accuracy.

[0020] (6) In the thermal conductance measurement system described in (4) above, at least three temperature measurement points are set on the one of the thermal conduction media at intervals along the direction of heat conduction from the heat source, and the calculation processing unit uses the temperatures measured by the temperature measurement unit at the at least three temperature measurement points and the intervals between the at least three temperature measurement points to determine whether the heat flow from the heat source is in a steady state or not, and calculates the thermal conductance of the heat source when it is determined that the heat flow is in a steady state. In the thermal conductance measurement system described in this section, at least three temperature measurement points are set in one of the two thermal conduction media of the thermal conduction modulation unit, which is to be disposed on the heat source side. These at least three temperature measurement points are set at intervals in the one thermal conduction medium along the conduction direction of heat flowing from the heat source.

[0021] The calculation processing unit then uses the temperatures measured by the temperature measurement unit at the at least three temperature measurement points and the intervals between the at least three temperature measurement points to determine whether the heat flow from the heat source is in a steady state. That is, the temperatures measured at the at least three temperature measurement points set on one of the heat conducting media are considered to linearly decrease from the heat source side according to the intervals between the temperature measurement points, if the heat flow from the heat source is in a steady state rather than a transient state. For example, if there are three temperature measurement points set at equal intervals, if the heat flow from the heat source is in a steady state, the temperature difference between the temperature measurement point on the heat source side and the temperature measurement point in the center is considered to be approximately equal to the temperature difference between the temperature measurement point in the center and the temperature measurement point on the cooling source side. Therefore, the calculation processing unit uses such a relationship to determine whether the heat flow from the heat source is in a steady state, and calculates the thermal conductance when it is determined to be in a steady state. This prevents thermal conductance from being measured when the heat flow from the heat source is in a transient state, and only measures thermal conductance when the heat flow is in a steady state, thereby improving the reliability of the thermal conductance measurement.

[0022] (7) In the above paragraph (4), at least one of the temperature measurement points is set in the one of the heat conduction media, and at least one of the temperature measurement points is set in the other of the heat conduction media, and the calculation processing unit determines whether the amount of heat passing through the heat conduction modulation unit is normal or not based on the magnitude relationship between the temperature measured by the temperature measurement unit at the temperature measurement point of the one of the heat conduction media and the temperature measured at the temperature measurement point of the other of the heat conduction medium, and calculates the thermal conductance of the heat source if it is determined to be normal. In the thermal conductance measurement system described in this section, at least one temperature measurement point is set in one of the two thermal conduction media of the thermal conduction modulation section, which is to be placed on the heat source side, and at least one temperature measurement point is set in the other thermal conduction medium, which is to be placed on the cooling source side.The calculation processing unit then determines whether the amount of heat passing through the thermal conduction modulation unit is normal or not based on the magnitude relationship between the temperature measured by the temperature measurement unit at the temperature measurement point of one of the thermal conduction media and the temperature measured at the temperature measurement point of the other thermal conduction medium.

[0023] That is, if the amount of heat passing through the thermal conduction modulation unit is normal, the temperature measured at the temperature measurement point of one of the thermal conduction media on the heat source side will be higher than the temperature measured at the temperature measurement point of the other thermal conduction medium on the cooling source side. On the other hand, if the amount of heat passing through the heat source is insufficient or the influence of the heat generating body is transient, it is assumed that the temperature measured at the temperature measurement point of the other thermal conduction medium on the cooling source side will be higher than the temperature measured at the temperature measurement point of one of the thermal conduction media on the heat source side. Such a relationship of magnitude of temperature is also applied between the temperature measurement point close to the heat source and the temperature measurement point close to the cooling source in the case where multiple temperature measurement points are set on each of the one thermal conduction medium and the other thermal conduction medium. Therefore, the calculation processing unit uses such a relationship to determine whether the amount of heat passing through the thermal conduction modulation unit is normal or not, and calculates the thermal conductance when it is determined that the amount of heat passing through the thermal conduction modulation unit is normal. This prevents thermal conductance from being measured even when the amount of heat passing through the thermal conduction modulation section is abnormal, and thermal conductance is measured only when the amount of heat passing through is normal, thereby improving the reliability of the thermal conductance measurement.

[0024] (8) In the thermal conductance measurement system described above in (4) to (7), the calculation processing unit, when calculating the thermal conductance of the heat source, further calculates a total thermal resistance from the heat source to the heat conduction path based on the difference between the first temperature and the second temperature and the heating energy when the first temperature is measured, and calculates the thermal resistance inside the heat source based on the total thermal resistance. The thermal conductance measurement system described in this section calculates the thermal resistance inside the heat source in addition to the thermal conductance of the heat source by the calculation processing section. That is, as mentioned in the above sections (1) and (3), the total thermal resistance calculated from the temperature change data and the heating energy includes the thermal resistance inside the heat source, the thermal resistance of the heat receiving part of the heat conduction path, and the thermal resistance of the heat conducting part of the heat conduction path. Therefore, using this, the calculation processing section calculates the thermal resistance inside the heat source based on the total thermal resistance as described above and the thermal resistance of the heat conduction path that is known because it is formed of a material with a known thermal conductivity, etc. As a result, the thermal resistance inside the heat source can be known even if the information inside the heat source is unknown. Effect of the Invention

[0025] Since the present invention is configured as described above, it is possible to grasp the thermal conductance of a heat source and contribute to the effective use of unused thermal energy. [Brief description of the drawings]

[0026] [Figure 1] 1 is a block diagram showing an example of a configuration of a thermal conductance measurement system according to an embodiment of the present invention. [Diagram 2] 1 is an image diagram showing an example of installation of a heat conduction path used in a thermal conductance measurement system according to an embodiment of the present invention, together with a model of thermal resistance from a heat source to the heat conduction path. [Diagram 3] 1A to 1D are diagrams showing an example of the structure of a thermal conductance modulation unit used in a thermal conductance measurement system according to an embodiment of the present invention, in which (a) is a top view, (b) is a side view, (c) is a bottom view, and (d) is a cross-sectional view taken along the line AA in (b). [Figure 4] FIG. 2 is a flow chart showing an example of a procedure of a thermal conductance measurement method according to an embodiment of the present invention. [Diagram 5] (a) is a schematic diagram showing the relationship between heat quantity and temperature, and (b) is an excerpt showing the thermal conductance in the schematic diagram of (a). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Hereinafter, the same or corresponding parts will be indicated by the same reference numerals throughout the drawings. Furthermore, detailed description of the same or corresponding parts as those in the prior art will be omitted. Fig. 1 shows an example of the configuration of a thermal conductance measurement system 10 according to an embodiment of the present invention for measuring the thermal conductance on a heat-receiving surface that can be extracted from a heat source 50 (see Fig. 2) to be measured, and for measuring the thermal resistance inside the heat source 50. As shown in the figure, the thermal conductance measurement system 10 includes a thermal conduction modulation unit 12, a cooling source 36, a heating element control unit 40, a temperature measurement unit 44, and a calculation processing unit 48. In addition, the thermal conduction modulation unit 12 includes a heating element 14 and two thermal conduction media 16, and Fig. 3 shows an example of a detailed structure of the thermal conduction modulation unit 12.

[0028] As shown in FIG. 3, the thermal conduction modulation section 12 has a configuration in which the heating element 14 is sandwiched between two thermally conductive media 16. In this embodiment, two cylindrical thermally conductive media 16 are connected by four bolts 24, and the heating element 14 is disposed between them. The heating element 14 is configured to vary the amount of heat generated by receiving varying heating energy, and in this embodiment, is formed by a Peltier element 14A, and a control line 32 is connected to supply power as heating energy to the Peltier element 14A. In addition, as can be seen in FIG. 3(d), a heat dissipation sheet 28 is disposed between the Peltier element 14A and the two thermally conductive media 16, thereby enhancing thermal conductivity. The surfaces of the two thermally conductive media 16 facing each other are provided with recesses for disposing the heat dissipation sheet 28 and a part of the Peltier element 14A.

[0029] The two heat conducting media 16 are formed of a material with a known thermal conductivity, such as aluminum or copper, but are not limited thereto. In addition, three measurement holes 20 are drilled in one of the two heat conducting media 16, the heat conducting medium 16A. In this embodiment, these three measurement holes 20 extend toward the center of the heat conducting medium 16A, which is circular in plan view as shown in FIG. 3(a), at positions equally spaced from each other in the vertical direction in FIG. 3(b) and (d). In addition, the three measurement holes 20 have temperature measurement points MP1 to MP3 set at positions near the center of the heat conducting medium 16A, which is circular in plan view. Therefore, the three temperature measurement points MP1 to MP3 are equally spaced from each other in the vertical direction in FIG. 3(d).

[0030] In contrast, one measurement hole 20 is drilled in the other heat conductive medium 16B of the two heat conductive media 16, and this one measurement hole 20 extends toward the center of the heat conductive medium 16B, which is circular in bottom view as shown in FIG. 3(c). A temperature measurement point MP4 is also set in the measurement hole 20 of this heat conductive medium 16B at a position near the center of the heat conductive medium 16B, which is circular in bottom view. That is, the temperature measurement points MP1 to MP4 are set near the heat conductive medium 14 in a positional relationship that sandwiches the heat conductive medium 14. Due to the number of measurement holes 20 and temperature measurement points MP as described above, the heat conductive medium 16A is larger in the vertical width in FIGS. 3(b) and (d) than the other heat conductive medium 16B.

[0031] The thermal conduction modulation unit 12 configured as above is used as a part of a thermal conduction path 54 that is installed so that heat is diverted from the heat source 50 to be measured, as shown in FIG. 2. In the embodiment of FIG. 2, a heat exchanger is installed through a heat outlet from the heat source 50, and the thermal conduction modulation unit 12 is further installed there through a thermal joint member. At this time, the thermal conduction modulation unit 12 is installed so that heat from the heat source 50 is conducted to one thermal conduction medium 16A, in other words, one thermal conduction medium 16A is arranged on the upper side in FIG. 2. Therefore, in the thermal conduction modulation unit 12, heat is conducted from the upper side to the lower side in FIG. 3(b) and (d). The other thermal conduction medium 16B of the thermal conduction modulation unit 12, which is to be arranged on the lower side in FIG. 2, is connected to the cooling source 36 also shown in FIG. 1 through a thermal joint member.

[0032] The cooling source 36 has a lower temperature than the heat source 50 to be measured, which generates a heat flow in which heat diverted from the heat source 50 flows toward the cooling source 36. For this reason, a model evaluation circuit is shown on the right side of Fig. 2, which likens the heat flow to an electrical flow, from the V heat source to GND via multiple R resistors. As can be seen from this circuit, each member constituting the heat conduction path 54 through which heat flows has a thermal resistance, and these thermal resistances can be understood by knowing the thermal conductivity, etc., of the materials constituting each member except for the heat source 50. 2 may be any heat source that contains unused thermal energy. Examples of such heat sources 50 include, but are not limited to, industrial plant equipment that handles thermal energy, various devices that use heat sources, combustion devices, internal combustion engines, incinerators, flow paths through which hot spring water flows, exhaust ducts, chimneys, steam pipes, and the like.

[0033] Returning to FIG. 1, the heating element control unit 40 controls the heating element 14 by applying a fluctuating heating energy to the heating element 14 of the thermal conduction modulation unit 12. In this embodiment, AC power (modulation power) of a predetermined frequency is supplied to the Peltier element 14A as heating energy via a control line 32 as shown in FIG. 3. The predetermined frequency of the AC power is set to a frequency different from the fluctuating frequency of the heat flow from the heat source 50 that is previously grasped. The temperature measurement unit 44 measures the temperature of the temperature measurement point MP set as described above in the thermal conduction medium 16 of the thermal conduction modulation unit 12. The temperature measurement unit 44 of this embodiment is configured to obtain the temperature of the temperature measurement point MP via, for example, platinum Pt100 or a thermocouple as a resistance temperature detector, and measure it quickly in a wide temperature range, although this is not limited thereto. The calculation processing unit 48 performs various calculation processes in the thermal conductance measurement system 10. Details of some of the calculation processes performed by such a calculation processing unit 48 will be described later.

[0034] Here, the thermal conductance measurement system 10 according to the embodiment of the present invention is not limited to the configuration shown in FIGS. 1 to 3, and some of the components shown in FIGS. 1 to 3 may be deleted or replaced, or new components may be added. Furthermore, each component in FIG. 1 shows the configuration of the thermal conductance measurement system 10 divided functionally, and does not show each device constituting the thermal conductance measurement system 10 as it is, but is composed of various hardware, software, or a combination thereof. For example, the heat generating body 14 may be composed of something other than the Peltier element 14A as long as it can be controlled so that the amount of heat generated varies. In addition, the heat conduction path 54 may be different from the configuration shown in FIG. 2 as long as it includes the heat conduction modulation unit 12 and the cooling source 36. Furthermore, the shape and number of each member of the heat conduction modulation unit 12 may be different from the embodiment of FIG. 3, and the number and positions of the temperature measurement points MP may be set arbitrarily.

[0035] Next, a thermal conductance measurement method according to an embodiment of the present invention, which is executed by using the above-mentioned thermal conductance measurement system 10, will be described with reference to Fig. 4. For the configuration of the thermal conductance measurement system 10, please refer to Figs. 1 to 3 as appropriate. Note that the flow diagram shown in Fig. 4 shows an example of the procedure flow of the thermal conductance measurement method, and the procedure of the thermal conductance measurement method is not limited to this flow diagram. For this reason, some of the steps shown in Fig. 4 may be changed, deleted, or rearranged, and new steps may be added.

[0036] S10 (connecting the heat conduction path): For example, as shown in Fig. 2, a heat conduction path 54 having a cooling source 36 at one end and a heat conduction modulation unit 12 in the middle is connected to the heat source 50 to be measured. At the same time, other components of the thermal conductance measurement system 10 are installed and connected. For example, the heat acquisition part of the temperature measurement unit 44 is installed at the temperature measurement point MP set in the heat conduction medium 16 of the heat conduction modulation unit 12. S20 (heating element control): The heating element control unit 40 starts to control the heating element 14 of the thermal conduction modulation unit 12. That is, in this embodiment, AC power having a predetermined frequency (modulation frequency) different from the fluctuation frequency of the heat flow from the heat source 50 is supplied to the Peltier element 14A so that the current waveform becomes a sine wave, for example.

[0037] S30 (temperature measurement): The temperature measurement unit 44 measures the temperature at the temperature measurement points MP set on the heat conductive medium 16. Specifically, the temperature is measured at the temperature measurement points MP1 to MP3 set on one heat conductive medium 16A of the heat conduction modulation unit 12 and the temperature measurement point MP4 set on the other heat conductive medium 16B. At this time, the measurement is performed at a sampling interval that is at least twice the modulation frequency of the AC power supplied from the heating element control unit 40 to the Peltier element 14A. Furthermore, for subsequent processing, the measured analog temperature data is converted to digital temperature data by the calculation processing unit 48 or a separately provided A / D converter. It is preferable that the A / D conversion at this time is performed with as high a resolution as possible. The temperature measured in this step corresponds to the first temperature (see symbol TW in FIG. 5(a)) when the temperature is affected by heat generated by the heating element 14 (when the temperature is modulated).

[0038] S40 (state determination): The calculation processing unit 48 determines whether the heat flow from the heat source 50 is in a steady state and whether the amount of heat passing through the thermal conduction modulation unit 12 is normal. First, the determination of the heat flow will be described. The calculation processing unit 48 determines the heat flow using the temperatures measured at the three temperature measurement points MP1 to MP3 of one of the heat conductive mediums 16A and the intervals between the three temperature measurement points MP1 to MP3. Specifically, if the heat flow from the heat source 50 is in a steady state, it is assumed that the heat flow from the heat source 50 side to the cooling source 36 side will linearly decrease. For this reason, in this embodiment in which the three temperature measurement points MP1 to MP3 are set at equal intervals, it is considered that the temperature difference between the temperature measurement point MP1 on the heat source 50 side and the central temperature measurement point MP2 in the heat conductive medium 16A and the temperature difference between the central temperature measurement point MP2 in the heat conductive medium 16A and the temperature measurement point MP3 on the cooling source 36 side will be approximately equal. On the other hand, if the heat flow from the heat source 50 is in a transient state, the above relationship breaks down, and an event occurs in which the temperature difference between the temperature measurement points MP1 and MP3 divided by 2 is not equal to the temperature difference between the temperature measurement points MP1 and MP2 or the temperature difference between the temperature measurement points MP2 and MP3. Using these, the calculation processing unit 48 judges whether the heat flow from the heat source 50 is in a steady state. Note that even if four or more temperature measurement points MP are set in one of the heat conductive media 16A, the heat flow can be judged using the above relationship.

[0039] Next, the determination of the amount of heat will be described. The calculation processing unit 48 determines the amount of heat by utilizing the magnitude relationship between the temperatures measured at the three temperature measurement points MP1 to MP3 of one heat conduction medium 16A and the temperature measured at the temperature measurement point MP4 of the other heat conduction medium 16B. Specifically, if the amount of heat passing through the heat conduction modulation unit 12 is normal, it is assumed that the temperature gradually decreases from the heat source 50 side to the cooling source 36 side. For this reason, in this embodiment, it is assumed that the measured temperatures at the temperature measurement points MP1, MP2, MP3, and MP4, which are arranged along the temperature transfer direction from the heat source 50 side to the cooling source 36 side, are in descending order in the order of their description.

[0040] On the other hand, if the amount of heat is abnormal due to excessive modulation by the heating element 14 (Peltier element 14A), the above relationship is lost, and for example, the temperatures at the temperature measurement points MP1 to MP3 become approximately equal, or the temperatures become lower than the temperature at the temperature measurement point MP4. Using this, the calculation processing unit 48 judges whether the amount of heat passing through the thermal conduction modulation unit 12 is normal or not. Note that even if two or less or four or more temperature measurement points MP are set in one thermal conduction medium 16A, or even if two or more temperature measurement points MP are set in the other thermal conduction medium 16B, the amount of heat can be judged using the above relationship. Then, in this step S40, if it is determined that the heat flow from the heat source 50 is in a steady state and the amount of heat passing through the thermal conduction modulation unit 12 is normal, the process proceeds to the next step. If a transient state of the heat flow or an abnormality in the amount of heat is detected, the configuration of the heat conduction path 54, the measurement timing, the AC power supplied to the Peltier element 14A, and the like are reviewed.

[0041] S50 (average temperature calculation): The calculation processing unit 48 calculates the average temperature of the temperatures measured in S30. That is, in this embodiment, since the Peltier element 14A is supplied with AC power to vary the heat generation amount, the influence (modulation) of the temperature fluctuation by the Peltier element 14A causes the temperature to fluctuate up and down in an AC manner. Therefore, for example, by calculating the average temperature by a moving average, temperature data that excludes the influence of the temperature fluctuation by the Peltier element 14A is extracted. At this time, processing is performed using a low-pass filter or the like set to filter characteristics that do not fluctuate the components that fluctuate due to modulation. Such calculation of the average temperature is performed for each temperature measurement point MP, or is performed only for a specific temperature measurement point MP, and the subsequent processing is performed using the data at the temperature measurement point MP where the average temperature was calculated in this step. Note that the temperature calculated in this step corresponds to the second temperature (see symbol T0 in FIG. 5(a)) when there is no influence of heat generation by the heating element 14 (unmodulated state).

[0042] S60 (difference calculation): The calculation processing unit 48 calculates the difference between the temperature (first temperature) measured in S30 above and the average temperature (second temperature) calculated in S50 above. This extracts temperature change data (see symbol ΔT in FIG. 5(a)) that has changed due to the influence (modulation) of the temperature fluctuation caused by the Peltier element 14A. S70 (frequency component extraction): The calculation processing unit 48 extracts data on the frequency components of the frequency (modulation frequency) of the AC power applied to the Peltier element 14A from the temperature change data calculated in S60. This eliminates noise such as fluctuation components of the heat flow from the heat source 50. Note that the extraction method here can be, for example, a method of extracting only the vicinity of the modulation frequency using a low-pass filter, a method of extracting using a band-pass filter centered on the modulation frequency, a method of performing synchronous detection (baseband detection), a method of performing two-stage shift detection using baseband detection or PSN modulators in multiple stages, and the like, but detailed explanations thereof will be omitted here.

[0043] S80 (calculation of thermal conductance): The calculation processing unit 48 calculates the thermal conductance of the heat source 50 to be measured. Here, Fig. 5(a) shows a schematic relationship between the amount of heat (unit: J) and the temperature (unit: K), where the mass of the heat source 50 is indicated by the symbol m, the specific heat of the heat source 50 is indicated by the symbol c, the temperature in the modulated state (first temperature) is indicated by the symbol TW, the temperature in the unmodulated state (second temperature) is indicated by the symbol T0, the original amount of heat of the heat source 50 is indicated by the symbol Q0, and the amount of heat including the heat generated by the heating element 14 is indicated by the symbol QW. That is, in a range where there is no phase change and the temperature change is minute, the amount of heat is proportional to the temperature with the mass m and the specific heat c as constants, so that the relationship shown in Fig. 5(a) is obtained and is expressed by the following formula. Q0(J)=m c T0(K) QW(J)=m c TW(K) FIG. 5(a) also shows that the heating energy applied to Peltier element 14A during modulation is designated by the symbol W (unit: J), and the difference between temperature TW in the modulated state and temperature T0 in the unmodulated state is designated by the symbol ΔT, and shows the relationship in the following formula and that the temperature has increased by ΔT due to the addition of heating energy W. QW(J)=Q0(J)+W(J)

[0044] From the above relationship, the following formula is established. m c = Q0(J) / T0(K) = QW(J) / TW(K) Furthermore, the following equation also holds for the temperature change ΔT caused in response to the heating energy W: m c = W (J) / ΔT (K) From these equations, the following relationship holds: Q0(J) / T0(K)=W(J) / ΔT(K) Q0(J)=T0(K) / ΔT(K)·W(J) However, since this formula does not include the ratio of each thermal resistance in the heat conduction path 54 shown in Fig. 2, it is necessary to take the modulation efficiency into consideration. Furthermore, since the heating energy W given to the Peltier element 14A during modulation is actually modulation power (AC power), the code for this is set to P (unit: W), and the modulation efficiency is expressed by the code η, taking into consideration the conversion between the heating energy W (J) and the modulation power P (W), resulting in the following formula: Q0(J)=T0(K) / ΔT(K)·P(W)·η(%) This formula shows that the heat quantity of the heat source 50 can be estimated based only on the temperature information that changes due to modulation, and if the modulation power P and modulation efficiency η are values ​​specific to the thermal conductance measurement system 10, then since only the thermal resistance of the heat source 50 is the unknown quantity, it shows that the thermal conductance of the heat source 50 can be estimated based on this formula.

[0045] Here, thermal resistance is the temperature difference between two points divided by the heat flow rate (amount of heat per unit time) flowing between the two points, and is therefore shown as the slope of the graph represented by "m·c" in Figure 5(a) (see symbol θ in Figure 5(b)). Therefore, if thermal resistance is designated Rth, it can be calculated using the following formula. Rth(℃ / W)=ΔT(K) / W(J) This thermal resistance Rth includes all thermal resistances within the heat conduction path 54 shown on the right side of Figure 2. Therefore, if the unknown thermal resistance of the heat source 50 is denoted by Rrs and the thermal resistance present in the measurement system is denoted by Rse, the thermal resistance Rrs of the heat source 50 can be calculated as follows: Rrs(℃ / W)=Rth(℃ / W)-Rse(℃ / W)

[0046] Furthermore, the thermal conductance excluding the heat receiving area of ​​the heat conduction path 54 for the heat source 50 as a general-purpose unit is expressed as the reciprocal of the thermal resistance. That is, "tan θ" in FIG. 5(b) corresponds to the thermal conductance of the heat receiving surface in contact with the heat source 50. The calculation processing unit 48 calculates the thermal conductance of the heat source 50 in this manner. At this time, it is important to handle the heat value including the modulation efficiency η, and it should be noted that the modulation power P (W) shown here is a value specific to the measurement system. And since the heat amount is defined as the heat amount per unit time, if the modulation power P can be adjusted and converted to 1 (J), the value of ΔT can be used as it is. Therefore, by skillfully adjusting the ratio with the modulation power P, the calculation formula is simplified and the load on the microcomputer and the like constituting the calculation processing unit 48 is further reduced.

[0047] S80 (calculate thermal resistance): The calculation processing unit 48 calculates the thermal resistance inside the heat source 50 to be measured. As mentioned in S80 above, the thermal resistance Rth (°C / W) including all the thermal resistances in the heat conduction path 54 shown on the right side of FIG. 2 is calculated as a combined resistance value corresponding to the following formula. Rth(℃ / W)= (R heat source + R bonding material + R device) × (R device + R bonding material + R cooling source) ÷ ((R heat source + R bonding material + R device) + (R device + R bonding material + R cooling source)) This is the thermal resistance found from the temperature measurement point MP, and Kirchhoff's first law and second law (Ohm's law) used in electrical circuit networks can be applied to the thermal resistance. This Rth is the value of the thermal resistance on the heat source side connected in series, that is, the parallel connection of the series values ​​of R heat source + thermal resistance value of R bonding material on the heat source side + total value of R device on the heat source side and R cold source + R bonding material on the cold source side + total value of R device on the cold source side. This is the parallel resistance calculation formula for the electrical circuits R1 and R2. Rth can be calculated as R = (R1 x R2) / (R1 + R2). However, the thermal resistance R of the modulation device is added to both the hot and cold source sides, and the ratio takes a value specific to the device, but here it is shown as a common value. Among the thermal resistors constituting the thermal resistance Rth as described above, all except for the R heat source have known thermal conductivity and other information of the material constituting each of them, so that the thermal resistance can be grasped. Therefore, the calculation processing unit 48 uses these information to calculate the thermal resistance (R heat source) inside the heat source 50.

[0048] In this case, if the thermal conductivity and shape dimensions of the heat exchanger connected to the heat source 50 and the thermal bonding member that conducts heat from there are measured in advance, and the heat flow is divided to form a heat flow circuit as shown in FIG. 2, the unknown thermal resistance is only the thermal resistance inside the heat source 50. In other words, the thermal resistance value inside the heat source 50 is calculated without obtaining the physical properties required for calculating the thermal energy, such as the mass, specific heat, density, and pressure, of the material that transfers the thermal energy in the above-mentioned device, such as the industrial plant equipment given as an example of the heat source 50. In addition, when a function that keeps the cooling side temperature constant, such as a circulator, is used, the thermal resistance value R cooling source of the cooling source 36 can be treated as close to zero as possible, so the calculation formula is further simplified. Furthermore, if the shapes of the thermal bonding member connected to the heat exchanger on the heat source 50 side and the thermal bonding member connected to the cooling source 36 are made the same, and the heat conduction path 54 is configured so that the thermal resistance values ​​(R bonding material) of each are the same, the calculation is further simplified.

[0049] In addition, when grasping the thermal resistance that takes a known value, it is necessary to estimate the temperature of the V heat source based on the temperature information measured at the temperature measurement point MP, taking into consideration the characteristics of the heat exchanger and the thermal conduction modulation unit 12 that have a temperature function. That is, since the temperature of the heat outlet where the heat exchanger that is the V heat source is attached is generally not measured, the thermal resistance of the known material that has the above temperature characteristics is estimated from the temperature information of the temperature measurement point MP. In this estimation work, the temperature information observed at the temperature measurement points MP1 to MP4 of the thermal conduction modulation unit 12, for example, is implemented in an electric circuit simulator using an electric circuit as an equivalent model evaluation circuit shown on the right side of FIG. 2. Then, a simulation is performed to simulate the transient phenomenon in which the V heat source changes from 0 volts to a predetermined voltage, and a parametric analysis is performed on the observed changes at the temperature measurement points MP1 to MP4 and the temperature function of the heat exchanger and the thermal conduction modulation unit 12 that have a temperature coefficient. Next, a thermal resistance value table with an appropriate temperature function is adopted based on a method for matching the temperature fluctuation observed at the temperature measurement point MP with the results of a simulation performed on a circuit simulator with V heat source as the circuit power supply voltage. As a result, even if the temperature of the heat exchanger's heat outlet is not measured, the thermal resistance inside the heat source 50 is calculated using the temperature changes at the temperature measurement points MP1 to MP4, regardless of the temperature of the heat source 50.

[0050] According to the embodiment of the present invention having the above configuration, the following effects can be obtained. That is, the thermal conductance measuring method according to the embodiment of the present invention uses a system 10 as shown in Figs. 1 to 3, for example, to measure the thermal conductance of a heat source 50 having unused thermal energy that is being exhausted. Specifically, by connecting one end of a heat conduction path 54 having a cooling source 36 at one end to the heat source 50 at the other end, heat is diverted so as to flow from the heat source 50 to the cooling source 36 (see S10 in Fig. 4). The heat conduction path 54 used at this time is formed of a material whose characteristics such as thermal conductivity are known in advance. In addition, the heat generating element 14 is installed in the heat conduction path 54, that is, between one end of the heat conduction path 54 where the cooling source 36 is installed and the other end of the heat conduction path 54 connected to the heat source 50. The heat generating element 14 to be installed is one that can be controlled so that the amount of heat generated varies when a varying heating energy W is applied.

[0051] Furthermore, the temperature in the heat conduction path 54 configured as described above is measured to obtain a first temperature TW when influenced by heat generated by the heating element 14 and a second temperature T0 when not influenced by heat generated by the heating element 14 (see S30, S50 in FIG. 4 and FIG. 5(a)). Next, a difference ΔT between the obtained first temperature TW and second temperature T0 is calculated to extract temperature change data ΔT that has changed due to the influence of the fluctuating heat generated by the heating element 14 (see S60 in FIG. 4 and FIG. 5(a)). Then, the thermal conductance of the heat source 50 is calculated based on the extracted temperature change data ΔT and the heating energy W given to the heating element 14 when the first temperature TW was measured.

[0052] That is, from the relationship shown in Figure 5(a), the "product of mass and specific heat" m·c can be expressed as the value obtained by dividing the "amount of heat in a state not receiving heating energy" Q0 by the "temperature in a state not receiving heating energy (second temperature)" T0, or the value obtained by dividing the "amount of heat in a state receiving heating energy" QW by the "temperature in a state receiving heating energy (first temperature)" TW. Furthermore, if radiation and thermal conduction that creates errors are so small that they can be ignored, the "product of mass and specific heat" m·c can also be expressed as the value obtained by dividing the heating energy W by the temperature change data ΔT.

[0053] In addition, since the thermal resistance is a value obtained by dividing the temperature difference between two points by the heat flow rate (amount of heat flowing per unit time) flowing between the two points, in the above-mentioned relationship, it can be expressed as a value obtained by dividing the temperature change data ΔT by the heating energy W. Then, considering that this thermal resistance includes all the thermal resistances from the heat source 50 to the heat conduction path 54, that the thermal conductance can be expressed as the reciprocal of the thermal resistance, and that the heat receiving area of ​​the heat conduction path 54, it can be seen that the thermal conductance per unit area can be calculated from the temperature change data ΔT and the heating energy W (see S80 in FIG. 4). As a result, it is possible to calculate the thermal conductance of the heat source 50 based on the temperature change data ΔT changed by the influence of the heating element 14 and the heating energy W given to the heating element 14 at that time, without needing to grasp the specific heat c or mass m of the heat source 50. Since the thermal conductance can be grasped in this way, it is possible to contribute to the effective use of unused thermal energy possessed by the heat source 50. Moreover, the thermal conductance can be determined even when information inside the heat source 50, such as the specific heat c, pressure, and physical density of the heat source 50, is unknown, or even when the pressure and density of the heat source 50 fluctuate over time.

[0054] The thermal conductance measuring method according to the embodiment of the present invention utilizes a Peltier element 14A as the heating element 14 installed in the thermal conduction path 54. The amount of heat generated from the Peltier element 14A is alternating-currently varied by applying AC power (modulation power) P of a predetermined frequency as heating energy W to the Peltier element 14A. The predetermined frequency of the AC power P is set to a frequency different from the fluctuating frequency of the heat flow from the heat source 50 to the thermal conduction path 54. Then, after calculating the difference ΔT between the first temperature TW when the temperature is affected by the heat generated by the heating element 14 and the second temperature T0 when the temperature is not affected by the heat generated by the heating element 14, data of the frequency component of the predetermined frequency described above is extracted from the calculation result (see S70 in FIG. 4). The thermal conductance of the heat source 50 is calculated based on the temperature difference data extracted in this way and the AC power P applied to the Peltier element 14A. That is, by applying a modulation power P of a frequency different from the fluctuation frequency of the heat flow from the heat source 50 to the Peltier element 14A and extracting and using the data of the frequency component of the modulation frequency, it is possible to calculate the thermal conductance while eliminating the fluctuation component of the heat flow, etc. This makes it possible to calculate the thermal conductance with greater accuracy.

[0055] In addition, the thermal conductance measurement method according to the embodiment of the present invention measures the thermal resistance inside the heat source 50 in addition to the thermal conductance of the heat source 50. As described above, the thermal resistance calculated from the temperature change data ΔT (the difference between the first temperature TW and the second temperature T0) and the heating energy W (the heating energy when the first temperature TW is measured) is the total thermal resistance including all the thermal resistances from the heat source 50 to the heat conduction path 54. That is, this total thermal resistance includes the thermal resistance inside the heat source 50, whose information such as specific heat, pressure, and density of physical properties is unknown, the thermal resistance of the heat receiving part of the heat conduction path 54 formed of a material whose characteristics such as thermal conductivity are known, and the thermal resistance of the heat conducting part of the heat conduction path 54. Therefore, the thermal resistance inside the heat source 50 can be calculated based on the total thermal resistance as described above and the thermal resistance of the heat conduction path 54, whose thermal conductivity is known and can be obtained by forming it of a material. As a result, even if information about the inside of the heat source 50 is unknown, it is possible to grasp the thermal resistance as information about the inside of the heat source 50 from the calculated total thermal resistance and the known thermal resistance information.

[0056] On the other hand, the thermal conductance measurement system 10 according to the embodiment of the present invention measures the thermal conductance on the heat receiving surface per unit area that can be collected from a heat source 50 having unused thermal energy, and includes a thermal conduction modulation unit 12, a cooling source 36, a heat generating element control unit 40, a temperature measurement unit 44, and a calculation processing unit 48, as shown in FIG. 1. The thermal conduction modulation unit 12 has a configuration in which a heat generating element 14 is sandwiched between two heat conducting media 16, as also shown in FIG. 3, and the heat generating element 14 can be controlled so that its heat generation amount varies, and the two heat conducting media 16 are formed of materials with known thermal conductivity. The thermal conduction modulation unit 12 having such a configuration is installed so that heat is conducted from the heat source 50 to be measured to one heat conducting medium 16A of the two heat conducting media 16. The cooling source 36 has a lower temperature than the heat source 50 to be measured, and is installed so that heat is conducted from the other heat conducting medium 16B of the two heat conducting media 16. That is, the thermal conduction modulation unit 12 and the cooling source 36 are installed as part of a thermal conduction path 54 that diverts heat from the heat source 50 so that heat flows from the heat source 50 toward the cooling source 36, as shown in FIG.

[0057] The heating element control unit 40 controls the heating element 14 of the thermal conduction modulation unit 12, and controls the heating element 14 so that the amount of heat generated from the heating element 14 varies by providing the heating element 14 with a varying heating energy W. The temperature measurement unit 44 measures the temperature of the temperature measurement point MP, which is set at a predetermined position on both or either of the two thermal conduction media 16A and 16B of the thermal conduction modulation unit 12, as shown in FIG. 3(d). The calculation processing unit 48 performs various calculation processes in the present system 10, and performs the following calculations as part of the calculations. That is, the calculation processing unit 48 obtains a first temperature TW when the temperature is affected by the heat generated by the heating element 14 and a second temperature T0 when the temperature is not affected by the heat generated by the heating element 14 from the measurement results of the temperature measurement point MP by the temperature measurement unit 44, as mentioned in the thermal conductance measurement method. Then, the difference ΔT between them is calculated to extract temperature change data ΔT that has changed due to the influence of the varying heat generated by the heating element 14.

[0058] Furthermore, the calculation processing unit 48 calculates the thermal conductance of the heat source 50 to be measured, as mentioned in the thermal conductance measurement method, based on the extracted temperature change data ΔT and the heating energy W given to the heat source 14 by the heat source control unit 40 when the first temperature TW is measured by the temperature measurement unit 44. This makes it possible to calculate the thermal conductance on the heat receiving surface that can be collected from the heat source 50 without the need to know the specific heat c or mass m of the heat source 50. Moreover, since the structure is such that heat is diverted from the heat source 50 to be measured via the heat conduction path 54 including the heat conduction modulation unit 12 and the cooling source 36, and the temperature is measured in the heat conduction modulation unit 12 in the heat conduction path 54, it is possible to measure the heat source 50 in various environments, including the heat source 50 through which a corrosive gas or a gas-liquid mixture with medium density fluctuation flows. Furthermore, there is no need to consider durability such as corrosion, and it is possible to significantly improve durability and reliability.

[0059] In the thermal conductance measurement system 10 according to the embodiment of the present invention, the heating element 14 of the thermal conduction modulation unit 12 is a Peltier element 14A, and the heating energy W given to the Peltier element 14A by the heating element control unit 40 is AC power P of a predetermined frequency, so that the amount of heat generated from the Peltier element 14A fluctuates in an AC manner. The predetermined frequency of the AC power P at this time is set to a frequency different from the fluctuating frequency of the heat flow flowing from the heat source 50 to the thermal conduction modulation unit 12, etc. Then, the calculation processing unit 48 calculates the difference ΔT between the first temperature TW when influenced by the heat generated by the heating element 14 and the second temperature T0 when not influenced by the heat generated by the heating element 14, and then extracts data of the frequency component of the above-mentioned predetermined frequency from the calculation result.

[0060] Furthermore, the calculation processing unit 48 calculates the thermal conductance of the heat source 50 based on the temperature difference data ΔT extracted in this manner and the AC power P applied to the Peltier element 14A by the heating element control unit 40. That is, as mentioned in the thermal conductance measurement method, by applying to the Peltier element 14A a modulated power P having a frequency different from the fluctuation frequency of the heat flow from the heat source 50 and extracting and using data of the frequency component of the modulated frequency, it is possible to calculate the thermal conductance while eliminating the fluctuation component of the heat flow, etc. This makes it possible to calculate the thermal conductance with greater accuracy.

[0061] In addition, in the thermal conductance measurement system 10 according to the embodiment of the present invention, as shown in Fig. 3, three temperature measurement points MP1 to MP3 are set in one of the two thermal conduction media 16 of the thermal conduction modulation unit 12, the thermal conduction medium 16A that is to be disposed on the heat source 50 side. These three temperature measurement points MP1 to MP3 are set at intervals in the one thermal conduction medium 16A along the conduction direction of heat flowing from the heat source 50 (the up and down direction in Fig. 3(d)). Then, the calculation processing unit 48 uses the temperatures measured by the temperature measurement unit 44 at the three temperature measurement points MP1 to MP3 and the intervals between the three temperature measurement points MP1 to MP3 to determine whether the heat flow from the heat source 50 is in a steady state (see S40 in Fig. 4). In other words, the temperatures measured at the three temperature measurement points MP1 to MP3 set on one of the thermally conductive mediums 16A are considered to decrease linearly from the heat source 50 side depending on the spacing between the temperature measurement points MP1 to MP3, provided that the heat flow from the heat source 50 is in a steady state rather than a transient state.

[0062] For example, as in the embodiment of FIG. 3, when three temperature measurement points MP1 to MP3 are set at equal intervals, if the heat flow from the heat source 50 is in a steady state, it is considered that the temperature difference between the temperature measurement point MP1 on the heat source 50 side and the temperature measurement point MP2 in the center and the temperature measurement point MP3 on the cooling source 36 side will be approximately equal. Therefore, the calculation processing unit 48 uses such a relationship to determine whether the heat flow from the heat source 50 is in a steady state or not, and calculates the thermal conductance when it is determined that the heat flow is in a steady state. This makes it possible to prevent the thermal conductance from being measured even when the heat flow from the heat source 50 is in a transient state, and to measure the thermal conductance only when the heat flow is in a steady state, thereby improving the reliability of the thermal conductance measurement.

[0063] Furthermore, in the thermal conductance measurement system 10 according to the embodiment of the present invention, one temperature measurement point MP4 is set in the other thermal conduction medium 16B, which is to be disposed on the cooling source 36 side, of the two thermal conduction media 16 in the thermal conduction modulation unit 12. Then, the calculation processing unit 48 judges whether the amount of heat passing through the thermal conduction modulation unit 12 is normal or not based on the magnitude relationship between the temperature measured by the temperature measurement unit 44 at the temperature measurement points MP1 to MP3 of one thermal conduction medium 16A and the temperature measured at the temperature measurement point MP4 of the other thermal conduction medium 16B (see S40 in FIG. 4). In other words, if the amount of heat passing through the thermal conduction modulation unit 12 is normal, the temperature measured at the temperature measurement points MP1 to MP3 of one thermal conduction medium 16A on the heat source 50 side will be higher than the temperature measured at the temperature measurement point MP4 of the other thermal conduction medium 16B on the cooling source 36 side.

[0064] On the other hand, when the amount of heat passing through the heat source 50 is insufficient or when the influence of the heat generating body 14 is transient, it is assumed that the temperature measured at the temperature measurement point MP4 of the heat conducting medium 16B on the cooling source 36 side will be higher than the temperature measured at the temperature measurement points MP1 to MP3 of the heat conducting medium 16A on the heat source 50 side. Such a relationship in magnitude of temperature is also applied to the three temperature measurement points MP1 to MP3 set on one heat conducting medium 16A. Therefore, the calculation processing unit 48 uses such a relationship to determine whether the amount of heat passing through the heat conduction modulation unit 12 is normal or not, and calculates the thermal conductance when it is determined to be normal. This makes it possible to prevent the thermal conductance from being measured even when the amount of heat passing through the heat conduction modulation unit 12 is abnormal, and it is possible to measure the thermal conductance only when the amount of heat passing through is normal, thereby improving the reliability of the thermal conductance measurement.

[0065] Moreover, the thermal conductance measurement system 10 according to the embodiment of the present invention calculates the thermal resistance inside the heat source 50 by the calculation processing unit 48 in addition to the thermal conductance of the heat source 50. That is, as mentioned in the thermal conductance measurement method according to the embodiment of the present invention, the total thermal resistance calculated from the temperature change data ΔT and the heating energy W includes the thermal resistance inside the heat source 50, the thermal resistance of the heat receiving part of the heat conduction path 54, and the thermal resistance of the heat conducting part of the heat conduction path 54. Therefore, by using this, the calculation processing unit 48 can calculate the thermal resistance inside the heat source 50 based on the total thermal resistance as described above and the thermal resistance of the heat conduction path 54, which is obtained because it is formed of a material whose thermal conductivity, etc. is known. This makes it possible to obtain the thermal resistance inside the heat source 50 even if the information inside the heat source 50 is unknown.

[0066] More specifically, it is common to represent the heat conduction circuit shown in FIG. 2, which shows the total thermal resistance, as a thermal circuit network, and the thermal circuit network as an electrical circuit network. For example, it is known to create a model by replacing thermal resistance with electrical resistance and applying Kirchhoff's first and second laws, and to calculate the balance of heat quantities at each junction by replacing it with Kirchhoff's first law. By using this calculation method, it is possible to grasp in advance the thermal resistance of the heat receiving part, the thermal resistance of the heat conducting part, the thermal resistance of the thermoelectric modulation unit 12, and the thermal resistance of the cold heat source 36, and thus the unknown thermal resistance is limited to the thermal resistance inside the heat source 50 as seen from the heat receiving part. Therefore, by making full use of Kirchhoff's theorem and electronic circuit simulators, which have recently evolved remarkably, and their inverse analysis tools, it is possible to identify the unknown part, that is, to calculate the thermal resistance inside the heat source 50.

[0067] Going further, the thermal resistance can be regarded as a scalar quantity specific to the heat source 50, which can be captured as an instantaneous value at that time as viewed from the thermal conductance measurement system 10. The fact that the scalar quantity in the heat source 50 can be accurately measured indicates that when multiple thermal conductance measurement systems 10 are installed on the path of the same heat source 50, the thermal resistance value inside the heat source 50 at measurement points with different position information can be accurately measured. For this reason, by further extending Kirchhoff's law, the multiple measurement points are set, for example, between two points separated by a certain distance, and the thermal resistance value inside the heat source 50 is grasped at each of them. Then, as the heat flow paths of each of the heat flow paths, a heat flow circuit equivalent to a Wheatstone bridge in an electric circuit can be configured, and an unknown thermal resistance connecting two points in the Wheatstone bridge in an electric circuit can also be obtained. Since this unknown thermal resistance indicates the internal thermal resistance connecting two points on the heat flow path, the range of application is expanded, and it becomes possible to measure the thermal resistance value of the heat medium between the installed heat flow paths.

[0068] Furthermore, by calculating the internal thermal resistance value not only as a scalar quantity but also as a vector quantity, and capturing the frequency fluctuation that occurs when the thermal fluctuation frequency propagates between two points at the other end, the moving speed of the medium that generates the heat flux between these two points can also be grasped. This is because the time difference in the heat flow fluctuation between the two points is regarded as a mutual temperature fluctuation, the above-mentioned second temperature change is regarded as a frequency change, and by capturing the phase change, the moving speed of the heat medium between these two points can be indirectly measured, making it possible to calculate the moving speed of the heat medium inside the heat source 50.

[0069] Furthermore, the ability to accurately measure the thermal resistance value inside the heat source 50 indicates that it is possible to grasp the amount of recoverable heat when reusing the surplus heat of the heat source 50. In other words, since it is possible to actually measure the thermal potential of the heat source 50, it is also possible to build a system that measures the amount of recoverable heat that can be reused from the heat source 50 being measured by setting a usable temperature range. [Explanation of symbols]

[0070] 10: thermal conductance measurement system, 12: thermal conduction modulation unit, 14: heating element, 14A: Peltier element, 16 (16A, 16B): thermal conduction medium, MP (MP1 to MP4): temperature measurement point, 36: cooling source, 40: heating element control unit, 44: temperature measurement unit, 48: calculation processing unit, 50: heat source, 54: thermal conduction path, W: heating energy, P: AC power (modulation power), TW: first temperature (temperature in modulated state), T0: second temperature (temperature in unmodulated state), ΔT: difference between first temperature and second temperature (temperature change data)

Claims

1. 1. A method for measuring thermal conductance of a heat source, comprising: A heat transfer path having a cooling source at one end and the other end connected to the heat source; a heat generating element that can be controlled so that the amount of heat generated varies by applying a varying heating energy to the heat conducting path is provided; measuring a temperature in the heat conduction path to obtain a first temperature when the heat conduction path is affected by heat generated by the heating element and a second temperature when the heat conduction path is not affected by the heat conduction path; A thermal conductance measuring method comprising: calculating a thermal conductance of the heat source based on a difference between the first temperature and the second temperature and the heating energy when the first temperature is measured.

2. A Peltier element is used as the heating element, As the heating energy, AC power having a predetermined frequency different from a fluctuating frequency of the heat flow from the heat source is applied, 2. The thermal conductance measuring method according to claim 1, further comprising the steps of: extracting data of a frequency component of the specified frequency from a calculation result of the difference between the first temperature and the second temperature; and calculating the thermal conductance of the heat source based on the extraction result.

3. 3. The thermal conductance measurement method according to claim 1, further comprising the steps of: when calculating the thermal conductance of the heat source, calculating a total thermal resistance from the heat source to the heat conduction path based on the difference between the first temperature and the second temperature and the heating energy when the first temperature is measured; and calculating the thermal resistance inside the heat source based on the total thermal resistance.

4. 1. A system for measuring thermal conductance of a heat source, comprising: a heat conduction modulation unit having a configuration in which a heat generating element that can be controlled to vary the amount of heat generated is sandwiched between two heat conducting media formed of materials with known thermal conductivity, and the heat conduction modulation unit is installed so that heat is conducted from the heat source to one of the two heat conducting media; a cooling source having a lower temperature than the heat source and installed so that heat is conducted from the other of the two heat conducting media; A heating element control unit that controls the heating element by applying a varying heating energy to the heating element; a temperature measuring unit that measures the temperature at a temperature measuring point set at a predetermined position on either or both of the two heat conducting media; A calculation processing unit that performs a calculation process, The calculation processing unit includes: calculating a difference between a first temperature when the device is affected by heat generated by the heating element and a second temperature when the device is not affected by the heat generated by the heating element from a measurement result of the temperature measuring unit; The thermal conductance measurement system calculates the thermal conductance of the heat source based on the difference and the heating energy when the first temperature is measured.

5. The heating element is a Peltier element, The heat generating element control unit applies, as the heating energy, AC power having a predetermined frequency different from a fluctuating frequency of the heat flow from the heat source, 5. The thermal conductance measurement system according to claim 4, wherein the calculation processing unit extracts data of the frequency component of the specified frequency from the calculation result of the difference between the first temperature and the second temperature, and calculates the thermal conductance of the heat source based on the extraction result.

6. At least three temperature measurement points are set in the one heat conduction medium at intervals along a direction of heat conduction from the heat source, The thermal conductance measurement system described in claim 4, characterized in that the calculation processing unit uses the temperatures measured at the at least three temperature measurement points by the temperature measurement unit and the intervals between the at least three temperature measurement points to determine whether the heat flow from the heat source is in a steady state, and calculates the thermal conductance of the heat source if it is determined that the heat flow is in a steady state.

7. At least one of the temperature measurement points is set in the one heat conducting medium, and at least one of the temperature measurement points is set in the other heat conducting medium, The thermal conductance measurement system of claim 4, characterized in that the calculation processing unit determines whether the amount of heat passing through the thermal conduction modulation unit is normal based on the magnitude relationship between the temperature measured by the temperature measurement unit at the temperature measurement point of one of the thermal conduction media and the temperature measured at the temperature measurement point of the other thermal conduction medium, and calculates the thermal conductance of the heat source if it is determined to be normal.

8. A thermal conductance measurement system as described in any one of claims 4 to 7, characterized in that when calculating the thermal conductance of the heat source, the calculation processing unit further calculates a total thermal resistance from the heat source to the heat conduction path based on the difference between the first temperature and the second temperature and the heating energy when the first temperature is measured, and calculates the thermal resistance inside the heat source based on the total thermal resistance.

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