JPH0672814B2 - 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 Conventionally, as shown in FIG. 5, a conventional heat detecting device of this type coats a heating element 1 with a coating 2 made of a jelly-like substance which substantially matches the temperature transfer coefficient of the skin of a human body, and the coating The detection body 3 including a thermocouple for detecting the temperature of the body 2 is provided,
A cover 5 formed in a spherical shape with a resin such as polyethylene having a large number of vent holes 4 and transmitting radiant heat is provided on the outside of the covering body 2, and has a power supply line 6 for the heating element 1 and the detection. An application has been filed for a heat detection element having a configuration in which a signal line 7 from the body 3 is provided (for example, Japanese Patent Laid-Open No. 60-170731). A signal corresponding to the thermal state of the environment is obtained from the signal line 7.

Problems to be Solved by the Invention However, in the above-mentioned configuration, the heating element and the temperature detecting element are separately required, and since a special material called a jelly-like substance is used, the structure is complicated and the productivity is poor. Also, in order to obtain a constant power supply circuit for constantly supplying a constant power to the temperature sensing element and a signal from the thermocouple as a temperature, a complicated and expensive circuit including a circuit such as reference temperature junction compensation and voltage amplification is required. There was a problem that it was necessary separately.

The present invention solves such a conventional problem, and while maintaining high productivity and low price with a small number of components and a simple structure, it can be used for collective detection of thermal effects of temperature, air flow, and radiant temperature, and microcomputer control. By realizing a suitable signal output with a self-heating element and a simple circuit, based on the information corresponding to the thermal sensation of the human body, the air conditioner can be controlled more finely than before and a comfortable warm space can be created. The purpose is to provide.

Means for Solving the Problems In order to solve the above problems, the heat detection device of the present invention is
A hollow body having an opening and an inner surface having good reflectivity to light and heat, a heating element made of a substance whose electric resistance value changes according to its own temperature provided inside the hollow body, and the heating element is fixed. The control means for maintaining the temperature of 1) and the judgment means for judging the thermal state of the environment from the change of the electric power supplied from the control means to the heating element.

Action The present invention has the above-mentioned configuration, and the heat generating element passes through the opening and is reflected by the surface of the hollow body to exchange radiant heat with surrounding objects and solar radiation, and at the same time, convective heat exchange with the secondary airflow inside the hollow body caused by ambient airflow. However, at this time, the shape and dimensions of the hollow body are formed so that the ratios of convective heat transfer and radiant heat transfer between the heating element and the surrounding environment substantially match those of the human body. The magnitude of the load for maintaining the constant temperature by the control means is obtained corresponding to the load for maintaining the constant body temperature of the human body. Since this load can be extracted as an electric signal and the thermal sensation of the human body can be judged from this output, a comfortable space can be easily realized by controlling the air conditioner based on this judgment. .

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. Ten
Is a heating element using a thermistor. As shown in detail in the partially cut-away perspective view of FIG. 2, the inner surface 13 is formed of aluminum or the like having an opening 12 and having good reflectivity for light and heat. It is composed of a hollow body 11.

The heating element 10 is controlled by the control means 14 so as to always generate heat at a constant temperature, and the determination means 15 can obtain information corresponding to the thermal sensation of the human body from the signal of the control load of the control means 14 at this time.

FIG. 3 shows an embodiment of the control means. The heating element 10, the operational amplifier 16, the fixed resistor 17, and the fixed resistor 1 are shown in FIG.
8.The temperature of the heating element 10 is controlled to be constant with the fixed resistor 19, and when the circuit is operated, the heating element 10 has the fixed resistor 17, the fixed resistor 19, and the fixed resistor 20. And the temperature of the heating element 10-heats to a certain temperature determined by the resistance characteristic.Here, any of the ambient air temperature, air flow, and radiant temperature is changed so that the temperature of the heating element is lowered. When working on, the thermistor heating element
Since the resistance of 10 rises and the potential at point b rises, the potential difference between points a and b is amplified by the operational amplifier 16 and the potential at point c rises, resulting in an increase in the current flowing through the heating element 10. The amount of heat generated by the heating element 10 increases due to the increase in the current, and the temperature of the heating element 10 rises and stabilizes at the original temperature. At this time, the potential at the point b or the point c is taken out to the control means 15 and the following processing is performed. The heat balance between the surface of the heating element 10 and the environment is expressed by the following equation.

Q = αc (Ts-Ta) + α r (Ts-Tr) ...... (1) However, Q: (load for controlling the temperature of the heating element constant) amount of heat radiation per unit surface area of the heat generating element alpha _c: Convective heat transfer coefficient between heating element and environment Ts: Temperature of heating element (controlled to be constant) Ta: Temperature α _r : Radiant heat transfer coefficient between heating element and environment Tr: Ambient radiation temperature The inner surface 13 is a parabolic curve surface By providing the heat generating element 10 at a position substantially at the focal point of the parabolic curved surface of the inner surface 13, radiation from the surrounding environment is converged on the heat generating element 10, and the heat generating element 10 has a hollow body around the periphery. Since it is arranged in the recess surrounded by 11, the velocity of the air flow directly contacting the heat generating element 10 is greatly attenuated, so that the radiant heat transfer coefficient α _r and the convective heat transfer of the heat generating element 10 are reduced. The coefficient α _c should be approximately equal to the radiant heat transfer coefficient and the average convective heat transfer coefficient of the human body. Therefore, the heat load for maintaining the heating element 10 at a constant temperature has a high correlation with the heat load required for the human body to maintain its 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 15, and the relationship between the load signal obtained by the control means 14 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, since it has directivity with respect to radiation, it is possible to detect the influence of radiation such as a wall surface of particular interest, and since the radiation is converged to increase the sensitivity, the heating element 10 is relatively provided.
It is possible to reduce the shape of the device and drive with low power consumption. Furthermore, the influence of the directionality on the air flow is small, and the influence can be detected equally in any direction.

Although a thermistor is used as the heating element here, a platinum resistor or the like may be used instead of the thermistor, and the inner surface 13 may be manufactured by resin-molding a curved surface and depositing a metal such as aluminum on the surface thereof. Is possible. The curved surface shape of the inner surface 13 is not limited to a simple parabolic curve, but a Winston mirror-like structure can be used.

EFFECTS OF THE INVENTION As described above, according to the heat detection device of the present invention, the following effects can be obtained.

(1) With a hollow body that reflects radiant heat and reduces the air flow, the convection and radiant heat transfer coefficient of the heating element can be made to substantially match the values of the human body, and the heating element is maintained at a constant temperature by the control means. Since there is a high correlation between the magnitude of the load and the thermal sensation of the human body, it is possible to optimally control the air conditioning equipment.

(2) Since the thermal state of the environment is detected by the change in electric power, and the level of the thermal state is determined based on this,
Information that is easy and easy to use can be given to the air conditioning equipment.

(3) Since the configuration is simple, high performance can be obtained at a low cost with a small number of parts, and it is easy to manufacture and has a wide range of applications as a sensor for heating and cooling equipment.

[Brief description of drawings]

FIG. 1 is a block diagram showing a heat detection device according to an embodiment of the present invention, FIG. 2 is a partially cutaway perspective view showing the structure of a heating element and a hollow body of the device, and FIG. 3 is a control means of the device. FIG. 4 is a characteristic diagram showing the contents of judgment made by the judgment means of the same device, and FIG. 5 is a partially cutaway perspective view showing the structure of the detection body of the conventional heat detection device. 10 ... Heating element, 11 ... Hollow body, 14 ... Control means, 15 ...
… Judgment means.

Claims (2)

[Claims] 1. A hollow body having an opening and an inner surface having good reflectivity to light and heat, and a heating element made of a substance provided in the hollow body, the electric resistance value of which changes according to its own temperature.
A heat detection device comprising: a control unit that maintains the heating element at a constant temperature; and a determination unit that determines the heating state of the environment based on a change in the power supplied from the control unit to the heating element. 2. The heat detection device according to claim 1, wherein the hollow body has a concave shape, and the heat generating element is provided at a substantially focal point of the concave shape.