JP2008026179A - Radiant heat sensor and method of measuring radiant heat - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve a highly useful high precision radiant heat sensor even with an extremely simple configuration. <P>SOLUTION: (1) Because measurement is performed while exhausting heat from a light reception surface so that a temperature of the light reception surface for the radiant heat is kept equal to the temperature of a measurement environment, outflow of heat from the light reception surface to the surroundings of the incident side does not occur, thereby performing precise measurement. (2) A thermoelectric element is used for the measurement of a heat flow value. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a radiant heat sensor and a radiant heat measurement method.

It is important for heat and energy management to know exactly how much light radiation and radiant energy is emitted from a certain object or how much light radiation and radiant energy reaches a certain place. By doing so, it is possible to take measures to prevent the wasteful flow of energy, and it is possible to predict the danger of high temperatures due to excessive energy accumulation. It can also be used to calibrate infrared radiation thermometers that are widely used today.

Thus, conventionally, a radiant heat sensor using a thermistor or a thermocouple has been proposed.
For example, there is disclosed a radiant heat sensor in which an inverted bowl-shaped concave mirror having an open front surface and a thermistor provided near the focal point of the concave mirror are provided, and radiant heat from the outside is collected by the concave mirror. (Patent Document 1)
In addition, a radiant heat receiving object is fixed with a support pin in a vacuum sealed chamber made of glass and a sealing plug, a thermocouple temperature measuring unit is joined to the radiant heat receiving object, and a thermocouple conductor is connected to the vacuum sealed chamber through the sealing plug. A radiant heat sensor is disclosed in which only a heat input by radiant heating is introduced into a radiant heat receiving object, and only a radiant heat transfer amount is measured by a temperature measuring part of a thermocouple joined to the radiant heat receiving object. (Patent Document 2)
Alternatively, when a bridge circuit is assembled with two thermosensitive elements having the same characteristics and two resistors, a switching means is provided, and the two thermosensitive elements are switched to a radiant heat detection element or an ambient temperature compensation element and switched. A differential amplifier amplifies the potential difference at the midpoint between each of the two thermosensitive elements and the two resistors, and stores the output voltage in the memory circuit unit. Thus, there is disclosed a radiant heat sensor in which the sensitivity is doubled, and the fluctuation of the detection value due to the fluctuation of the ambient temperature is extremely small and the measurement accuracy is improved. (Patent Document 3)

JP-A-5-079676 JP-A-7-128149 Japanese Patent Laid-Open No. 9-005169

However, the conventional radiant heat sensor has the following problems and is insufficient for accurate radiant heat measurement.
In Patent Document 1, the radiation heat flow measurement method / apparatus uses a phenomenon in which the temperature of the light receiving surface increases due to radiant heat, and calculates the amount of incident energy from the increased temperature. In this method, heat flows out from the high temperature light receiving surface to the incident side due to the rise in the light receiving surface temperature, and it is difficult to accurately measure the amount of incident energy.

Therefore, in Patent Document 2, in order to prevent the influence of the rise in the temperature of the light receiving surface, at least a part of an object having a coating that easily absorbs radiant heat such as black plating or black paint is applied to at least a part of the radiant heat receiving surface, and radiant heat such as glass is applied. It is characterized in that it is structured to absorb only radiant heating by being fixed in a vacuum or reduced pressure sealed container made of a transmitting material, and the temperature rise of this object is measured from the outside with an infrared radiation thermometer or the like. However, it is difficult to manufacture an object provided with a film that easily absorbs radiant heat in a sealed container that is vacuumed or decompressed. Also, this method can eliminate heat conduction due to air around the detector and heat outflow due to convection, but it cannot reduce heat release due to radiation.

Patent Document 3 is a thermistor bolometer type radiant heat sensor. Switching means for switching between the two sensors, for example, changing the angle of the rotating reflector to alternately switch the radiant heat to one of the heat sensitive elements, or forming the heat sensitive element into a thin film and sandwiching the heat insulating sheet A device that controls the rotation angle of the motor and switches it alternately so that either one of the heat-sensitive elements detects radiant heat by rotating with the bonding motor is required. Again, heat leaks from the temperature riser cannot be eliminated. Also, thermistors need to be corrected due to aging. Therefore, the present invention has been made in view of such circumstances, and an object thereof is to provide a highly accurate radiant heat sensor with an extremely simple configuration.

The present inventors previously filed a patent application for a method for evaluating the characteristics of thermoelectric elements, and developed and used a highly sensitive and reliable thermal measurement method and apparatus using the thermoelectric element as a heat flow sensor. . In addition, we have applied for a patent related to the “assembled desktop experiment system” and are continuing to develop a small experimental device that can be used in a desktop space. With this assembly-type desktop experiment system, we have intensively developed a radiant heat sensor used for radiant heat energy experiments.

Therefore, in order to solve the above-mentioned problem, if the amount of exhaust heat is measured while exhausting heat from the light receiving surface so that the temperature of the light receiving surface of radiant heat is kept equal to the temperature of the measurement environment, Accurate measurement is possible without any heat outflow. In addition, attention is paid to the fact that the structure is simple if a thermoelectric element is used to measure the heat flow value. Therefore, the present invention is configured as follows.

The invention of claim 1 includes a thermoelectric element (1) in which a thermoelectric element pair (2) is sandwiched between substrates (3A, B), an exhaust heat section (4) disposed on one of the substrates (3A), Radiant heat characterized by having a temperature sensor (5) disposed at the junction between the substrate (3A) and the exhaust heat section (4) and a temperature sensor (6) disposed on the other substrate (3B). It is a sensor.

The invention according to claim 2 is characterized in that the temperature sensor (5) disposed at the junction between the substrate (3A) and the exhaust heat section (4) has a temperature control section for controlling the temperature sensor to match the ambient temperature. The radiant heat sensor according to claim 1.

The invention of claim 3 has a current supply part for supplying current to the thermoelectric element (1) so that the temperature detected by the temperature sensor (5) of the other substrate (3A) and the ambient temperature are the same. The radiant heat sensor according to claim 1 or 2.

Invention of Claim 4 has a voltage measurement part which measures the voltage between terminals of thermoelectric element (1), It is a radiant heat sensor of any one of Claim 1 to 3 characterized by the above-mentioned.

The invention according to claim 5 is the radiant heat sensor according to any one of claims 1 to 4, wherein the surface of the substrate (3B) is a black body.

The invention according to claim 6 is the radiant heat sensor according to any one of claims 1 to 5, wherein the thermoelectric element (1) is a thermo module in which a plurality of thermoelectric element pairs (2) are combined. is there.

The invention of claim 7 collects radiant heat from the outside on the light receiving surface, exhausts heat from the light receiving surface so that the temperature of the light receiving surface is kept equal to the temperature of the measurement environment, measures the amount of exhaust heat, and determines the amount of exhaust heat. A method for measuring radiant heat, characterized in that the amount of received radiant heat is used.
The invention of claim 8 collects radiant heat from the outside in a thermoelectric element having a light receiving surface, and exhausts heat from the light receiving surface of the thermoelectric element so that the light receiving surface temperature of the radiant heat is kept equal to the temperature of the measurement environment. 8. The method of measuring radiant heat according to claim 7, wherein a potential difference between terminals of the thermoelectric element is measured, and an amount of exhaust heat is determined based on the measured value.

The invention of claim 8 collects radiant heat from the outside in a thermoelectric element having a light receiving surface, and exhausts heat from the light receiving surface of the thermoelectric element so that the light receiving surface temperature of the radiant heat is kept equal to the temperature of the measurement environment. 8. The method of measuring radiant heat according to claim 7, wherein a potential difference between terminals of the thermoelectric element is measured, and an amount of exhaust heat is determined based on the measured value.

The present invention configured as described above performs measurement while exhausting heat from the light receiving surface so that the temperature of the light receiving surface of the radiant heat is kept equal to the temperature of the measurement environment. It is possible to accurately measure the amount of incident energy without heat flowing out to the side periphery.

Further, since a thermoelectric element is used for measuring the heat flow value, the structure is relatively simple. Since it is not necessary to fix it in a vacuum or reduced pressure sealed container, it is easy to manufacture and can be miniaturized. Therefore, it can be implemented as a small experimental device module that can be assembled and used in a desktop space.

Embodiments of the present invention (hereinafter referred to as the present invention) will be described below with reference to the drawings. The technical scope of the present invention is not limited to the examples.

(Basic structure)
A thermoelectric element (thermo module, TM) 1 is used as a heat flow sensor. The TM arrangement is shown in FIG. TM1 has a structure in which a large number of thermoelectric element pairs (TE) 2 are sandwiched between two insulating substrates (A, B) 3. One substrate 3A is attached to the heat exhausting portion (HS) 4, and the temperature sensor (TS1) 5 is attached to the joint. Various heat radiation components such as a stack fin, an air cooling fan, a Peltier module, a heat pipe, and a water-cooled heat sink can be used for the exhaust heat unit.
(Temperature control)

In the present invention configured as described above, control is performed so that the temperature at TS1 matches the ambient temperature Tr. The other substrate 3B of TM is used as a radiant heat receiving portion, and a temperature sensor (TS2) 6 is attached to the light receiving surface of the substrate 3B. When constant radiant heat _JR is incident on the light receiving surface, the temperature of TS2 rises and eventually reaches a steady value Ts.
(The heat flow inside the TN)

When current I is passed through TM1 and Peltier heat transport occurs, the value of Ts changes. For example, Ts = Tr can be obtained by adjusting the direction and magnitude of this current to an appropriate value by a switching power supply. The current at this time is I ₀ . At this time, the temperature distribution inside TM1 is as shown in FIG. 1b, and there is a temperature difference ΔT between the upper and lower contacts of TE2.

Also, the heat flow inside TM1 is as shown by the arrows in FIG. 1a. Where J _R is the incident radiant heat flow, Jr is the reflected heat flow at the light receiving surface, J _NB is the conduction heat flow in the substrate 3B, J _NE is the conduction heat flow in TE2, J _P is the Peltier transport heat, and J _NA is the substrate A The conduction heat flow in, J _NHS, is the conduction heat flow in HS4. The heat flow J _N flowing through the TM is as follows.
(Measurement of radiant heat)

Accordingly, (see by the inventors reference 1) in the circuit configuration of the block diagram shown in FIG. 2, by measuring the potential difference V _m between TM7 terminals in conduction, the value of J _N is the determined by the following equation. In the figure, 7 is TM) (thermo module), and 8 is a heat exhausting part.
Here, n is the logarithm of the thermoelectric element, Π is the Peltier coefficient, η is the Seebeck coefficient, Z is the thermal resistance of TE, and R is the electrical resistance of TE. The values of Π, η, Z, and R can be measured by the method described in Reference 2 by the present inventors. FIG. 3 shows an example of the measurement step. These are controlled by a personal computer to display the measurement results.
(High precision)

The reflected heat flow Jr on the light receiving surface depends on the state of the light receiving surface. This can be reduced at least by making the surface of the substrate 3B a black body.
(References by the inventors)

1) K. Tozaki, Y. Kido, Y. Koga and K. Nishikawa; Novel
Method of Measuring Heat Capacity of Supercritical Fluid Using Peltier
Elements, Jpn. J. Appl. Phys., 45 (2006) 269-273
2) K. Tozaki and K. Sou; Novel Determination of
Peltier Coefficient, Seebeck Coefficient and Thermal Resistance of
Thermoelectric Module, Jpn. J. Appl. Phys. 45 (2006) 5272-5273

As described above, the present invention is extremely useful because a highly accurate radiant heat sensor can be realized with an extremely simple configuration in spite of an extremely simple configuration.

Configuration of the radiant heat sensor of the present invention, internal heat flow (a), TM internal temperature distribution (b). The block diagram of the measurement system of this invention. Measurement process of the present invention

Explanation of symbols

1 ... Thermoelectric element (Thermo module, TM)
2 ... Thermoelectric element pair (TE)
3 ... Board (A, B)
4 ... Waste heat section 5 ... Temperature sensor (TS1) 5
6 ... Temperature sensor (TS2) 6
7 ... Thermoelectric element (Thermo module, TM)
8 ... Waste heat section

Claims (8)

A thermoelectric element (1) having a thermoelectric element pair (2) sandwiched between substrates (3A, B);
An exhaust heat section (4) disposed on one side of the substrate (3A);
A temperature sensor (5) disposed at a joint between the substrate (3A) and the exhaust heat section (4);
A radiant heat sensor comprising a temperature sensor (6) disposed on the other substrate (3B). The temperature sensor (5) disposed at the junction between the substrate (3A) and the exhaust heat section (4) has a temperature control section for controlling the temperature sensor to match the ambient temperature. Radiant heat sensor. 2. A current supply unit for supplying current to the thermoelectric element (1) so that the temperature detected by the temperature sensor (5) of the other substrate (3A) and the ambient temperature are the same. Or the radiant heat sensor of 2. The radiant heat sensor according to any one of claims 1 to 3, further comprising a voltage measuring unit that measures a voltage between terminals of the thermoelectric element (1). The radiant heat sensor according to any one of claims 1 to 4, wherein the surface of the substrate (3) is a black body. The radiant heat sensor according to any one of claims 1 to 5, wherein the thermoelectric element (1) is a thermo module in which a plurality of thermoelectric element pairs (2) are combined. Collecting radiant heat from the outside to the light receiving surface, exhausting heat from the light receiving surface so that the temperature of the light receiving surface is kept equal to the temperature of the measurement environment, measuring the amount of exhausted heat, and making the amount of exhausted heat the amount of received radiant heat A characteristic method of measuring radiant heat. Radiation heat from the outside is collected in a thermoelectric element having a light receiving surface, and the temperature of the light receiving surface of the radiant heat is exhausted from the light receiving surface of the thermoelectric element so as to be kept equal to the temperature of the measurement environment. The method of measuring radiant heat according to claim 7, wherein the amount of exhaust heat is determined from the measured value.