JPH0511766B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention detects the thermal state of the environment, which serves as control data for the air conditioner, for example, when an air conditioner provides a comfortable indoor environment for the human body. The present invention relates to a thermal sensing element for use in the human body, and particularly to one that takes into consideration humid heat radiation accompanying moisture evaporation from the skin surface of the human body.

(Prior art) In general, there is a limit to the ability to maintain a room in a thermal state that is comfortable for the human body by controlling an air conditioner based only on the indoor air temperature. It is necessary to evaluate the actual residential thermal environment by combining each physical quantity. and,
Thermal detection elements for detecting such thermal conditions are required to be manufactured in such a way that a thermal correlation is established between the element and the human body, based on the thermal equilibrium of the human body. Ru.

By the way, as this type of thermal detection element, conventionally, as disclosed in Japanese Patent Application Laid-Open No. 58-218624, an electric heating element consisting of an electric heater arranged in a hollow spherical shell, It is equipped with a temperature measuring device that measures the surface humidity of the body, and by supplying a predetermined amount of heat to the heating element by energizing the electric heater and then measuring the surface temperature, the thermal state of the environment can be calculated by taking into account radiation. Those that have been designed to detect this are known.

(Problems to be Solved by the Invention) However, in the conventional method described above, heat loss (heat dissipation) from the human body is limited to dry heat dissipation due to radiation and convection, and humid heat dissipation that occurs as moisture evaporates from the skin surface. is not considered. Therefore, it has been difficult to evaluate the thermal state in an actual living space as accurately as human sensation.

Therefore, the present invention has been made in view of the above, and an object of the present invention is to provide a heat detecting element equipped with a heating element made of a single shell such as a spherical shell as described above. By taking into account humid heat dissipation due to moisture evaporation from the surface and specifying the dimensions of the heating element and the amount of heat supplied to the optimal range to satisfy the conditions, the temperature sensing element is made to more closely approximate the actual human sensation. Therefore, the object is to be able to detect the actual indoor thermal environment with extremely high accuracy.

(Means for Solving the Problems) In order to achieve the above object, the solving means of the present invention is as shown in FIG. The shell body 3
A heating element 1 in which a radiant material layer 8 having an emissivity substantially matching the spectral emissivity based on the human body is formed on the outer surface of the heating element 1, and a temperature measuring device 7 for measuring the surface humidity Tg of the heating element 1. , assumes a thermal detection element that supplies a predetermined amount of heat to the heating element 1 and then detects the thermal state of the indoor environment based on the surface humidity Tg. Then, the dimensions of the shell 3 of the heating element 1 and the amount of heat M supplied to the heating element 1 are adjusted so that the convective heat transfer coefficient of the heating element 1 almost matches the convective heat transfer coefficient with evaporation of the human body, and the heating element By making the amount of heat supplied to the heating element 1 almost match the amount of heat dissipated from the skin surface taking into account the thermal resistance of human clothing, the thermal equilibrium characteristics of the heating element 1 become equivalent to the thermal equilibrium characteristics of the human body, taking into account moisture heat radiation. The configuration is set as follows.

Here, the dimensions of the shell 3 of the heating element 1 and the method for limiting the amount of heat M supplied to the heating element 1 will be explained in detail below.

That is, the thermal equilibrium equation for the thermal sensing element shown in Figure 1 is: M=h gr (Tg - Tr) + h gc (Tg - Ta)
...(1) (Tg: surface temperature of the heating element, Tr: average radiant temperature of the indoor environment, Ta: air temperature, h gr: radiant heat transfer coefficient of the heating element, h gc: convective heat transfer coefficient of the heating element) Become. On the other hand, when calculating the amount of heat dissipated from the skin surface of the human body under any non-isothermal environment, Hsk=R+C+E...(2 ), and the above heat losses R, C, and E are expressed by the following equations.

R=hr・Fcl・(Tsk−Tr) …(3) C=hc・Fcl・(Tsk−Ta) …(4) E=w・k・hc・Fpcl・(Psk−φa・Pa)
...(5) (However, hr: radiation transfer coefficient of the human body, hc: convective heat transfer coefficient of the human body, Tsk: average skin temperature, φa: relative humidity, Psk: saturated vapor pressure at average skin temperature Tsk,
Pa: saturated vapor pressure at temperature Ta, w: skin wet area ratio, Fcl: coefficient indicating thermal resistance of clothing, Fpcl: permeability of clothing to water vapor evaporating from the skin surface to the surroundings, k: Lewis relationship 2.2 at sea level) Here, we will evaluate indoor thermal comfort by introducing a new standard effective temperature SET ^* , which has been set by the American Air Hygiene Society ASHRAE and is closely related to human thermal sensation and comfort. In this case, if SET ^* is determined so that the amount of dissipated heat calculated based on the theory is equal to Hsk in equation (2) above, Hsk = hs・Fcls (Tsk − SET ^* ) + w・k・hcs・
Fpcls (Psk−0.5P _SET ^* ) …(6) (where, hcs: convective heat transfer coefficient of the human body in standard airflow, hs: radiant heat transfer coefficient of the human body, hcs) Added heat transfer coefficient, P _SET
^* : Saturated water vapor pressure at SET ^* , Fcls: Clothing amount 0.6clo
Thermal resistance coefficient of clothing, Fpcls: amount of clothing
Transmittance of clothing to evaporated water vapor at 0.6clo). In other words, SET ^* is given by equation (2)
The amount of heat equal to Hsk in the standard state (clothing amount 0.6clo,
The temperature is defined as an isothermal environment where airflow velocity is 0.1 to 0.15 m/s, humidity is 50%, Tr = Ta) and can be dissipated under equal physiological conditions (Tsk, w are equal),
Depends on the air temperature Ta, average radiant temperature Tr, and airflow velocity.For example, amount of clothing is 0.6clo, humidity is 50%, heat production is 1Met (=
58.2W/m ² ) air flow velocity is 0.1-0.15m/
When s, if SET ^* is SET ^* = 22.2 to 25.6℃
More than 80% of people are thermally comfortable
It is approved by ASHRAE.

In the thermal equilibrium equation of the human body shown by equation (2) above,
Considering the moisture heat dissipation, the temperature is around the comfortable range (temperature 22-26
C+E on the right side can be approximated by C+E=hc′・Fcl(Tsk −Ta) …(7) (where hc′: convective heat transfer coefficient with evaporation), the above equation (2) is: Hsk/Fcl=hr(Tsk−Tr)+hc′(Tsk−Ta ) ...(8) can be rewritten.

When comparing equations (1) and (8) above, if the following relationships hold: h gr=hr...(9) h gc=hc'...(10) M=Hsk/Fcl...(11) , when the surface temperature Tg of the heating element becomes equal to the average skin temperature Tsk of the human body, Tg=Tsk...(12) Display Tg as KET ^* ).

On the other hand, when ^moisture heat radiation is incorporated into convective heat loss in SET ^* mentioned above, the above equation (6) becomes The total heat transfer coefficient due to convection, evaporation, and radiation is From equations (12) and (13) above, SET ^* = KET ^* −Hsk/(Fcls・hs′) …(14), and considering the vicinity of the comfort zone, the second right-hand side of equation (14)
The term can be approximated as a constant.

Therefore, by measuring the heating element surface temperature KET ^* that has a transfer characteristic that satisfies the conditions of equations (9) to (11) above, SET ^* can be approximately determined, and the thermal sensing element This means that thermal evaluation can be performed strictly under the actual living environment.

Therefore, in the present invention, in order to satisfy the conditions of equations (9) to (11) above, we have developed the characteristics regarding the air flow velocity and average radiant temperature of SET ^* considering humid heat radiation in the standard state and near the comfort zone, and the above heating element. The amount of heat M supplied to the heating element (1) is adjusted to match the same characteristics of the surface temperature KET ^* .
and its dimensions.

In other words, when the air velocity is 0.1 m/s as the reference state, and the air velocity changes from the reference state to 1 m/s, each change in SET ^* and KET ^* due to the change in air velocity Amount △SET ^* , △
The average value of the square of the difference between KET ^* S S = (△ ^* −△ ^* ) ² ...(15) was calculated, and the dimensions of the shell (3) of the heating element (1) were set to various values. If we calculate the amount of heat M to be supplied such that the average value S is the minimum for each dimension above, and plot the minimum average value S for each dimension, we get
For example, if the shell (3) is a spherical shell, the characteristics shown in FIG. 2 can be obtained by taking the diameter D on the horizontal axis. In addition, the surface temperature Tg of the heating element (1) is calculated based on equation (1), and the convective heat transfer coefficient h gc of the heating element (1) is related to the forced convection heat transfer of the sphere shown in (16) below. Use an empirical formula.

Nu=2+0.645Re ^0.505 ...(16) (Nu: Nusselt number, Re: Reynolds number) In addition, Fig. 3 shows the amount of heat supplied M (Met=58.2W/ m ² ) is shown, and once the diameter D is determined, the optimum amount of heat to be supplied M that minimizes the root mean square value S at that time is determined. FIG. 4 shows changes in the optimum amount of heat M to be supplied when the diameter D of the spherical shell changes. Therefore, from these figures 2 to 4, in order to reduce the root mean square value S and obtain a highly accurate thermal sensing element, the amount of heat supplied M and the spherical shell diameter D
It turns out that it is necessary to specify.

In addition, in the same way as above, the state where the average radiant temperature Tr and the air temperature Ta are equal (Tr = Ta) is set as the reference state, and when Tr-Ta changes from -5℃ to +5℃, that Tr-Ta changes. If the above-mentioned root mean square value S regarding the amount of change ΔSET ^* and ΔKET ^* in SET ^* and KET ^* due to the increase/decrease change is plotted for each diameter D, the characteristics shown in FIG. 5 are obtained.
The amount of heat M to be supplied to the heating element (1) is the value determined when determining the characteristics related to the change in air flow velocity (Fig. 4 shows the optimum amount of heat M to be supplied for each diameter D).

Therefore, in the present invention, in the case of a spherical shell, △SET ^* and △ are calculated based on the characteristics shown in FIGS. 2 and 5 for each change in air velocity and the difference between the average radiant temperature Tr and the air temperature Ta. In order to establish an extremely close correlation with KET ^* , the diameter D of the heating element (1) is set to D = 60.
Specify the range of ~150 mm, and calculate the amount of heat M supplied to the heating element (1) for this diameter D range from M=76 to
It can be specified in the range of 105W/ ^m2 .

That is, to explain the specific reason, as shown in FIG. 5, as the diameter D of the spherical shell becomes smaller, the root mean square value S increases significantly, and the performance as a sensing element deteriorates. Here, when the average radiant temperature Tr is changed, △KET ^* is directly proportional to this Tr,
△SET ^* is also almost directly proportional to Tr, so
As Tr increases, (△SET ^* −△KET ^* ) also increases. Therefore, if we allow (△SET ^* -△KET ^* ) up to 0.1°C for a 1°C change in the above average radiation temperature Tr, then in Figure 5, Tr is changed from -5°C to +5°C, so The root mean square value S becomes S=0.1 from the above equation (15). From Fig. 5, the range where S≦0.1 is D for the diameter D of the spherical shell.
≧60mm. On the other hand, since it is easier to use the temperature sensing element if its size and dimensions are small, the upper limit of the diameter D was set to 150 mm. This diameter D = 60~150mm
From Fig. 4, the optimal amount of heat to be supplied M corresponding to M =
76 to 105 (W/m ² )=1.3 to 1.8 (Met).

Note that the shape of the shell (3) is not limited to the above-mentioned spherical shape, and various shapes such as a cylindrical shape and a spheroidal shape can be adopted. In these cases, the same method as above is used to make the dimensions of the heating element (1) and the amount of heat M supplied to the heating element (1) equivalent to the thermal equilibrium characteristics of the human body, taking into account the moisture heat radiation. can be specified. As an example, in the case of a cylinder, using the equation of Igarashi and Hirata regarding forced convection heat transfer of the cylinder below, Nu=0.373Re ^1/2 +0.057Re ^2/3 ...(17) As in the case of a sphere, (15) above for the diameter D of
When the values of the root mean square value S obtained by the formula are plotted, the change characteristics with respect to the air velocity and the average radiant temperature are shown in Figs. 6 and 7, respectively.
In this case, it is found that the diameter D is preferably 80 mm or more. In addition, the optimal amount of heat supplied at this time M is 76W/m ²
That's all.

(Function) With the above configuration, in the present invention, the dimensions of the shell (3) of the heating element (1) in the thermal detection element and the heating element
Since the amount of heat M supplied to (1) is set after taking into account the humid heat dissipation of the human body, the thermal equilibrium of the element has a very close correlation to the thermal equilibrium of the human body, giving a sense of comfort to the human body. This means that the applied thermal state can be detected with high precision using a single sensing element.

Furthermore, the dimensions of the heating element (1) and the supplied heat amount M,
When setting the equivalence with the thermal equilibrium characteristics of the human body, moisture heat radiation was also taken into consideration, making it possible to reduce the size of the heating element (1). That is, FIG. 8 shows the convective heat transfer coefficient hgc with respect to the diameter D of the shell (3) in a thermal sensing element having a heating element (1) in the shape of a shell (3) such as a sphere or a cylinder. Convection transmissibility hc of human body
It also shows the level of the convective transmissivity hc′, which takes into account the moisture heat radiation defined by equation (7) above. As shown in the figure, as the diameter D increases, hgc decreases, so hc and hgc
From the diameter D _A , which was determined to match the
Diameter D _B determined to match hc′ and hgc
has a smaller value, and the dimensions can be reduced.

Furthermore, since a radiant material layer (8) having an emissivity that approximately matches the spectral emissivity based on the human body is formed on the outer surface of the spherical shell (3) of the heating element (1), the heating element of the sensing element
(1) The radiant heat transfer coefficient h gr of the surface can be accurately matched to the radiant heat transfer coefficient hr of the human body, and the thermal state in the actual living environment can be detected more precisely by the thermal detection element. can.

(Example) Next, an example of the present invention will be described based on the drawings.

FIG. 1 shows a thermal detection element A for controlling an air conditioner according to an embodiment of the present invention. In the same figure, 1
is a spherical heating element, and the heating element 1 has an electric heater 4 sealed in the center of a hollow spherical shell 3 made of metal such as copper, which is fixed through a pipe-shaped support rod 2. . Power supply lines 6, 6 are connected to the heater 4 to supply power to the heater 4 through an electric insulator 5 filled and fixed in the support rod 2. It is fixedly supported within the shell 3.

Further, a thermocouple 7 is fixed to the inner surface of the spherical shell 3 of the heating element 1 as a temperature measuring device for measuring the temperature Tg of the surface of the heating element 1 (spherical shell 3). The output of the thermocouple 7 is led out of the spherical shell 3 through the insulator 5 and the support rod 2, and the electric heater 4 is energized to generate heat and supply a predetermined amount of heat to the heating element 1.
In this state, the surface temperature Tg of the heating element 1 is detected by the output voltage of the thermocouple 7, and the thermal state of the indoor environment is detected based on this.

Further, on the outer surface of the spherical shell 3 of the heating element 1, a fluororesin such as tetrafluoroethylene resin (PTFE) and titanium oxide (Ti
A thin radiant material layer 8 made of a predetermined pigment such as O ₂ )
is formed.

The present invention is characterized by the diameter D of the spherical shell 3 of the heating element 1 and the amount of heat M supplied to the heating element 1.
(Electrical input to the electric heater 4) is made to be equivalent to the thermal equilibrium characteristics of the human body, taking into account moisture heat radiation.
Specifically, D=60~150mm, M=76~
It is set in the range of 105W/ ^m2 .

Therefore, in the above embodiment, the heating element 1
The diameter D of the spherical shell 3 and the amount of heat M supplied to the heating element 1
is set to be equivalent to the thermal equilibrium characteristics of the human body, taking into account wet heat dissipation, so for the reasons explained above, the thermal balance of the wet heat sensing element A can be extremely closely approximated to that of the human body. By detecting KET ^* by thermal detection element A, it is possible to accurately detect SET ^* in the actual thermal environment.

Furthermore, since a radiant material layer 8 mainly composed of a fluororesin having an emissivity that substantially matches the spectral emissivity of human skin or clothing is formed on the outer surface of the spherical shell 3 of the heating element 1, the sensing element A The radiant heat transfer coefficient h gr of the surface of the heating element 1 can be precisely matched to the radiant heat transfer coefficient hr of the human body, and the thermal state in the actual living environment can be detected even more precisely by the thermal detection element A. can do.

Furthermore, in the thermal equilibrium of the human body, the convective heat transfer coefficient hc' with evaporation is set, and the heat transfer coefficient hc' is made to match the convective transfer coefficient h gc of the heating element 1. The diameter D of the heating element 1 can be set small without using a heating element cover that covers the heating element 1 to transmit radiant heat to the heating element 1 and suppress convection.

(Specific Example) Finally, a specific example will be described. In the thermal sensing element having the configuration of the above embodiment, the diameter D of the heating element is set to D = 100 mm, the amount of heat supplied M is set to M = 92.2 W/m ² (1.585 Met), and care is taken about the sensing element. Flow rate from 0.1 to
When we calculated the amount of change △KET ^* in KET ^* from the reference state (air velocity 0.1 m/s) when changing it in the range of 1.0 m/s, we found the characteristics shown by the solid line in Figure 9. was gotten. The broken line in the figure shows the characteristics of the amount of change ΔSET ^* in SET ^* under the same conditions.

In addition, for the same sensing element as above, the difference Tr−Ta between the average radiant temperature Tr and the air temperature Ta in the indoor environment is −
The characteristic of ΔKET ^* from the reference state (when Tr=Ta) when varied in the range of 5 to +5° C. is as shown by the solid line in FIG. In the figure, the broken line indicates the characteristics of △SET ^* .

Therefore, according to FIGS. 9 and 10, according to the thermal detection element of the present invention, △KET ^* is △ for each change in the air velocity and the difference Tr−Ta between the average radiant temperature Tr and the air temperature Ta. It can be seen that there is an extremely good correlation with SET ^* , and that the detection accuracy in the actual thermal environment can be improved.

(Effects of the Invention) As explained above, according to the thermal detection element of the present invention, the dimensions of the heating element made of a hollow shell in which an electric heater is enclosed and the amount of heat supplied by the heating element are determined in consideration of the humid heat dissipation of the human body. Since it is specified by
The thermal equilibrium of the thermal detection element is made to closely approximate the thermal equilibrium of the human body, and the thermal state in an actual living space can be evaluated to the same degree as the bodily sensation. In addition, as a result, the size of the heating element can be reduced by considering moisture heat dissipation, and it is therefore possible to provide a highly accurate and compact thermal sensing element that is ideal for controlling the operation of air conditioners. It is something.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a thermal sensing element in an embodiment of the present invention. Figure 2 is a characteristic diagram of the change in air flow velocity of the root mean square value for the diameter in the case of a spherical shell.
Figure 3 is a characteristic diagram of the change in the root mean square value with respect to the amount of heat supplied when the diameter is 100 mm, Figure 4 is a characteristic diagram of the change in the optimum amount of heat supplied with respect to the diameter, and Figure 5 is the difference between the average radiant temperature and the air temperature. It is a characteristic diagram of the root mean square value with respect to the increase/decrease change of. Figures 6 and 7 respectively show 2 for the diameter in the case of a cylindrical shell.
FIG. 8 is a characteristic diagram of the variation of the root mean value with respect to the air velocity and the average radiant temperature, and FIG. 8 is a characteristic diagram of the convective heat transfer coefficient with respect to the diameter of the shell body. Figures 9 and 10
The figures show △KET ^* for the air velocity and the difference between the average radiant temperature and the air temperature when the diameter of the heating element and the amount of heat supplied are specified to predetermined values within the range of the present invention, respectively.
It is a characteristic diagram shown in comparison with SET ^* . A... Temperature sensing element, 1... Heating element, 3... Spherical shell, 4... Electric heater, 7... Thermocouple, 8... Radiant material layer.

Claims (1)

[Claims] 1. Heat generation in which an electric heater 4 is disposed inside a hollow shell 3, and a radiant material layer 8 having an emissivity that substantially matches the spectral emissivity based on the human body is formed on the outer surface of the shell 3. body 1, and a temperature measuring device 7 for measuring the surface temperature Tg of the heating element 1,
A thermal detection element that supplies a predetermined amount of heat to the heating element 1 and detects the thermal state of the indoor environment based on the surface temperature Tg of the heating element 1. The amount of heat supplied is determined so that the convective heat transfer coefficient of the heating element 1 almost matches the convective heat transfer coefficient with evaporation of the human body, and the amount of heat supplied to the heating element 1 is determined by adjusting the amount of heat supplied to the heating element 1 from the skin surface taking into account the thermal resistance of the human body's clothing. A thermal detection element characterized in that the thermal equilibrium characteristics of the heating element 1 are set to almost match the amount of heat dissipated, and are set to be equivalent to the thermal equilibrium characteristics of the human body, taking into account even moisture heat radiation.