JPH0672810B2 - Thermal detector - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting a thermal state of an environment in an air conditioner that provides a comfortable environment for humans.

2. Description of the Related Art A configuration considered prior to the present invention will be described with reference to FIG. In FIG. 6, reference numeral 1 is a heating element using a thermistor, and a spherical cover 2 made of polyethylene resin that transmits radiant heat is provided outside the heating element 1 and the spherical cover 2 is used to attenuate the air flow. An opening 3 is provided for guiding around the heating element 1. The heating element 1 is controlled by the control means 4 so as to always generate heat at a constant temperature. At this time, the convective heat transfer coefficient and the radiant heat transfer coefficient of the heating element 1 are substantially the same as those of the human body by the spherical cover 2. Therefore, the determination means 5 can obtain information corresponding to the thermal sensation of the human body from the signal of the control load of the control means 4.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in the above-mentioned configuration, since the heating element needs to be constantly heated to a constant temperature, the battery is consumed quickly and practically used especially when the battery is used as a power source. It had a problem that it was not appropriate.

The present invention solves such a conventional problem, and when the power consumption exceeds a certain value, the heat generation of the element is stopped to reduce the power consumption and enable the battery drive.
By realizing the collective detection of the thermal influence of airflow / radiation temperature on the human body with a self-heating element and a simple circuit, the object is to perform fine control of the air conditioner and to provide a comfortable warm space.

Means for Solving the Problems In order to solve the above problems, the heat detection device of the present invention is
A heat-generating element made of a substance whose electric resistance value changes according to its own temperature, a cover which transmits radiant heat to the heat-generating element and reduces an air flow, a control means for maintaining the heat-generating element at a constant temperature, and the heat generation. Judging means for judging the thermal state of the environment from the change of the electric power supplied to the heating element from the control means in order to keep the temperature of the element constant, and energizing the heating element according to the value of the supplied electric power. It is configured by a power limiting means for limiting and a timer.

Effect The present invention has the above-mentioned configuration, and suppresses the power by the power limiting means in accordance with the increase in the power consumption of the heating element
At the time of measurement, the heat generating element exchanges radiant heat with the surrounding object through the cover, radiant heat and convective heat exchange with ambient air, and at this time, the cover causes convective heat transfer and radiant heat transfer between the heat generating element and the ambient environment. Since the proportion is made to substantially match that of the human body, the magnitude of the load for maintaining the heating element at a constant temperature by the control means is obtained corresponding to the load for maintaining the body temperature of the human body at a constant value. Is taken out as an electric signal, and the thermal sensation of the human body can be judged from this output with power saving.

Embodiments Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a block diagram of the heat detection device of the present invention. A heating element 1 using a thermistor, a cover 2 formed of a resin such as polyethylene that transmits radiant heat, the heating element 1
To a constant temperature, a determination means 5 for determining a value corresponding to the thermal sensation of the human body based on a control load signal from the control means 4, and a heating element to the heating element according to a control load signal from the control means 4. Power control means 6 for stopping the energization of the heating element 1 and timer 7 for starting the operation when the energization of the heating element 1 is stopped by the power limiting means 6 and outputting a signal to the power limiting means 6 after counting a certain time. It is composed by. As shown in detail in the partially cut-away perspective view of FIG. 2, a cover 2 formed of a resin such as polyethylene that transmits radiant heat is provided on the outside of the heating element 1, and the cover 2 is provided to attenuate the air flow. The heating element 1
A large number of openings 3 are provided for leading to the surroundings.

A series of operations of this apparatus will be described with reference to FIG. When the power is turned on 8, the control means 4 operates 9 to generate heat in the heating element 1. At this time, at 10 the power Q supplied from the control means 4 to the heating element 1 (voltage in the circuit is changed). Is measured and the resistance of the heating element 1 is constant and known, so the power value at that time is known.
If it does not exceed Qc, the information of the power Q is output to the judging means 5.
Then, the loop 12 is rotated, but if Q> Qc, the operation of the control means 4 is stopped by the power control means 6 and then 14
Then, the counting of the timer 7 is started, and the fixed time is counted at 15. When the fixed time has elapsed, the timer 7 is reset 16, and the measurement is restarted by returning to the operation 9 of the control means. This device performs this series of operations.

FIG. 4 shows a circuit diagram of the control means 4.

When the control means 4 operates, the heating element 1 has a temperature resistance characteristic of the heating element 1 itself, a fixed resistor 17, a fixed resistor.
18, the resistance value of the fixed resistor 19 and the power supply voltage, heat is generated to a certain temperature determined by the voltage drop in the operational amplifier 20, etc.
If any of the ambient temperature, air flow, or radiant temperature changes to act to lower the temperature of the heating element, the resistance of the heating element 1 which is the thermistor rises and the potential at the point b rises. The potential difference between the points a and b is amplified by the amplifier 20 and the potential at the point c rises, resulting in an increase in the current flowing through the heating element 1. This increase in current increases the amount of heat generated by the heating element 1, The temperature of the heating element 1 rises and stabilizes at the original temperature. At this time, the potential at the point b is taken out to the judging means 5 via the voltage follower 21.

The heat balance between the surface of the heating element 1 and the environment is expressed by the following equation.

Q = α _c (T _s −T _a ) + α _r (T _s −T _r ) ... (1) However, Q: heat radiation amount per unit surface area of the heating element (load for controlling the temperature of the heating element to be constant ) Α _c : Convective heat transfer coefficient between the heating element and the environment T _s : Temperature of the heating element (constant control) _Ta : Air temperature α _r : Radiant heat transfer coefficient between the heating element and environment T _r : Ambient radiation temperature where The radiant heat transfer coefficient α _r of the surface of the heating element 1 is made to substantially match the radiant heat transfer coefficient of the surface of the human body, and the opening 3 of the cover defines the convective heat transfer coefficient α _c of the heating element 1 as the average convective heat of the human body. Since the thermal load is set to be approximately equal to the transmissibility, the thermal load obtained is highly correlated with the load required to maintain the body temperature in the same environment. A table for correcting the non-linearity of the thermistor is stored in the ROM of the one-chip microcomputer in advance in the judging means 5, and the relationship between the load signal obtained by the control means 4 as shown in FIG. 5 and the thermal sensation of the human body. Is expressed in the form of a mathematical formula or table, which allows the temperature, airflow, and
Since an output almost equivalent to the thermal sensation of the human body caused by the radiant temperature can be obtained, if the air conditioner is controlled so that this sensation is neutral, a comfortable environment is always maintained.

According to the above configuration, when the power consumption of the heating element increases, the circuit is stopped, and the circuit is activated again after a certain time has elapsed by the timer, so that the circuit can be simply configured and the power consumption can be reduced. Furthermore, in this configuration,
By connecting a voltmeter to the output of the voltage follower 21 and setting the scale corresponding to the thermal sensation, it can be used alone as a portable thermal detection device.

Effects of the Invention As described above, according to the heat detection device of the present invention, since the energization to the heating element is limited according to the power consumption of the heating element,
Energy saving that can save power consumption,
It is possible to extend the life of the battery driven by the battery.

[Brief description of drawings]

FIG. 1 is a block diagram of a heat detection device according to an embodiment of the present invention, FIG. 2 is a partially cutaway perspective view showing the configuration of a heating element and a cover of the device, and FIG. 3 is a flow chart of the operation of the device. FIG. 4 is a flow chart, FIG. 4 is a circuit diagram showing the configuration of the control means of the apparatus, FIG. 5 is a graph showing the contents of the determination made by the determination means of the apparatus, and FIG. It is a block diagram including a partially cutaway perspective view showing. 1 ... Heating element, 2 ... Cover, 4 ... Control means, 5 ...
… Judgment means, 6 …… Power limit means, 7 …… Timer.

Claims (2)

[Claims] 1. A heating element made of a substance whose electric resistance changes according to its own temperature, a cover for transmitting radiant heat to the heating element and reducing an air flow, and a control for maintaining the heating element at a constant temperature. Means for determining the temperature of the environment from the change of the electric power supplied from the control means to the heating element in order to keep the temperature of the heating element constant, and the heat generation according to the value of the supplied electric power. A thermal detection device comprising a timer and a power limiting means for limiting the power supply to the element. 2. The heat detection device according to claim 1, wherein the power limiting means stops the energization of the heating element under a certain condition and resumes the energization after a lapse of a certain time after the energization is stopped by a timer.