JPH0352568B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an element for detecting the thermal state of an environment in an air conditioner that provides a comfortable environment for the human body.

Conventional elements for detecting the thermal state of an environment of this type include a thermal detecting element such as a thermistor attached to an indoor air intake port of an air conditioner or a space to be air conditioned to detect the air temperature.

In this case, the thermal state of the air-conditioned space is controlled by operating the air conditioner based only on the air temperature, but the comfort of people in the space is affected not only by the air temperature but also by radiant heat, airflow, and humidity. Therefore, there was a limit to controlling the temperature to a comfortable temperature using only air temperature.

In order to improve this, there are control devices that operate the air conditioner by installing a humidity sensing element, a radiation sensing element, etc. in addition to the air temperature sensing element, and logically combining the signals from those elements. , the number of elements is increasing and it is becoming more complex.

In addition, when a heating element equivalent to the thermal balance between the human body and the thermal state of the space is used as a thermal detection element, the equivalent diameter of the heating element becomes large, about 15 cm, and the thermal state of the space is detected and the air conditioner is activated. The detection element is too large to operate, making it impractical.

The present invention eliminates these conventional drawbacks and provides a compact and single thermal sensing element that correlates with human comfort in sensing the thermal status of an air-conditioned space. .

The present invention provides a heating element whose outer surface has an emissivity that roughly matches the emissivity of a human skin surface or clothing, a sensing element that detects the temperature of the heating element, and a space provided around the outer periphery of the heating element to cover the heating element. It consists of a heating element cover molded from a resin such as polyethylene and having a large number of uniform ventilation holes throughout.

With this configuration, the heating element generates heat using electric power supplied from the outside through the power supply line, transmits through the heating element cover and exchanges radiant heat with surrounding objects and sunlight, and connects with the surrounding air through the ventilation holes of the heating element cover. Due to the convective heat exchange of , a heat balance occurs and as a result the temperature of the heating element is determined. This heat balance mechanism is correlated with the heat balance of the human body, so the signal from the detector that detects the temperature of this heating element can be used to detect air temperature, airflow, and radiation, which have a significant impact on comfort, with a single thermal detection element. This means that the air conditioner can be controlled.

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

In the figure, 1 is the main body of the thermal detection element, which consists of a spherical heating element 2, a heating element cover 4 formed into a spherical shape from a resin such as polyethylene that has many ventilation holes 3 and transmits radiant heat, and a support metal fitting 5. The heating element 2 is equipped with a heater 7 inside a spherical outer shell 6 and a detection element 8 made of a thermocouple for detecting the temperature of the outer shell 6. A line 9 and a signal line 10 from the sensing body 8 are provided.

With this configuration, from the power supply line 9 to the heater 7
When a constant power Hg is supplied to the heating element 2, the heat balance of the heating element 2 is as shown below, and the temperature Tg of the heating element 2 is determined.

Hg／Ag＝αcg(Tg−Ta)＋αrg(Tg−Ta)……(1) However, Hg: Supply power Ag; Surface area of heating element αcg: Convective heat transfer coefficient between heating element and surrounding air αrg: Heat generation Radiant heat transfer coefficient between the body and the surrounding air Tg: Heating element temperature Ta: Ambient temperature Tr: Ambient radiation temperature On the other hand, the human body also generates heat and radiates that heat to the outside world, so if only dry heat radiation is considered, the heat balance is as follows.

{1+R(αcb+αrb)}Hb/Ab = αcb(Ts−Ta)+αrb(Ts−Tr) ……(2) However, Hb: Dry calorific value of the human body Ab: Body surface area of the human body αcb: Relationship between the human body and the surrounding air convective heat transfer coefficient αrb: radiation heat transfer coefficient between the human body and surrounding objects R: thermal resistance of clothing Ts: human body skin surface temperature Here, the power supplied to the heating element 2 is calculated as shown in equation (3). After adjustment, equations (1) and (2) become equation (4).

Hg＝Ag／AbHb……(3) Hb／AbR(αcb+αrb)＝αcb・Ts−αcg・Tg ＋αrb・Ts−αrg・Tg−(αcb−αcg)・Ta−(αrb−αrg)Tr… ...(4) If the emissivity of the outer surface of the heating element 2 is roughly matched to the emissivity of the surface of the human body, the equation (5) is obtained.

αrb=αrg≡αr (5) Furthermore, the heating element cover ventilation hole is opened so that the equation (6) is satisfied so as to reduce the airflow.

αcb＝αcg≡αc……(6) From equations (4), (5), and (6), Ts＝Tg＋R・Hb／Ab……(7) The relationship between Ts and thermal comfort is expressed by the third As shown in the figure, it is uniquely determined, so when Tg is obtained from the signal from the sensing body, the equation (7 )Than
Ts is determined and the comfort of the air-conditioned space is evaluated.

In order to have a heat balance equivalent to that of the human body, the radiant heat transfer coefficient αr and the convective heat transfer coefficient αc of the human body and the thermal sensing element must be roughly matched.
In other words, in order to match the radiation heat transfer coefficient αr, the emissivity of the surface of the human body and the emissivity of the outer surface of the heating element 2 in the thermal detection element should be roughly matched, and attenuation due to radiation transmission through the heating element cover 4 should be made. In order to suppress this as much as possible, it is essential to use a material with high radiation transmittance, such as polyethylene.

As shown in Figure 4, the convective heat transfer coefficient αc is the relationship between the equivalent diameter of the object and the wind speed around the object; the larger the equivalent diameter, the smaller αc, and the larger the wind speed, the larger αc. be.

When the wind speed v around the human body is v ₁ , the convective heat transfer coefficient αc of the human body is αcb, but at the same wind speed v ₁ , the convective heat transfer coefficient αc of a heating element whose diameter is equivalently smaller than that of the human body is αcg, which is an order of magnitude larger. Therefore, it can be seen that in order to match αcb and αcg, the equivalent diameter must be approximately 15 cm.

Conversely, for a heating element with an equivalent small diameter to obtain a convective heat transfer coefficient of the same value as αcb, the wind speed v around the heating element must be reduced to v ₂ .

As a means to reduce this, a heating element cover 4 having a large number of ventilation holes 3 is provided.

That is, as shown in FIG. 5, most of the airflow having a wind speed of v ₁ in front of the sensing element flows backward along the outer periphery of the heating element cover 4. A part of it passes through the ventilation hole 3 of the heating element cover 4, flows around the heating element 2, and flows out from the ventilation hole 3 at the rear.

The airflow flowing in and out through the ventilation hole 3 is attenuated by the fluid resistance at the ventilation hole 3, and in order to sulfurize only a part of the front flow, the airflow is attenuated to a wind speed v ₂ as shown in FIG. The convective heat transfer coefficient αc of the heating element 2 at that time approximately matches the convective heat transfer coefficient αcb of the human body.

As described above, the temperature, airflow, and radiation as the thermal state of an air-conditioned space can be detected using a small and single thermal detection element that correlates with human comfort.

Furthermore, the working conditions and clothing conditions of people in the space can be given as parameters, making it possible to obtain even more detailed control and maintain comfort.

As described above, according to the thermal sensing element of the present invention,
By using a heating element cover that transmits radiant heat to the heating element and reduces airflow, it is possible to detect temperature, airflow, and radiation as a thermal state with a small and single element, and to detect multiple The air conditioner can be operated to easily provide a comfortable thermal state without requiring a complicated control device using elements.

In addition, the heating element is covered with a heating element cover that has a space around the outer periphery and a large number of uniform ventilation holes throughout, and the airflow that hits the heating element passes from the ventilation hole through the space on the outer periphery, and from the opposite ventilation hole. Since the airflow is attenuated while being discharged and does not directly hit the heating element, the convective heat transfer coefficient is reduced, and the size of the heating element can be reduced to achieve a heat transfer coefficient equivalent to that of the human body. Furthermore, due to the miniaturization, the response to environmental changes becomes faster and the control performance of the air conditioner is improved. Furthermore, since the heating element cover is not just a protective member but is composed of uniform porous holes throughout and a radiation transmitting material such as polyethylene, it also has heat transfer by radiation.

[Brief explanation of drawings]

Fig. 1 is an external view showing one embodiment of the thermal sensing element of the present invention, Fig. 2 is a sectional view of the thermal sensing element, and Fig. 3 is a relationship diagram showing the correlation between the skin surface temperature of the human body and comfort. , Fig. 4 is a relationship diagram showing the correlation between wind speed and convective heat transfer coefficient, Fig. 5 is an explanatory diagram of a thermal detection element in an air flow with wind speed, and Fig. 6 is a diagram showing the relationship between wind speed around a heating element and around a human body. It is a relationship diagram showing a relationship. 1...Main body, 2...Heating element, 3...Vent hole, 4
...Heating element cover, 8...Detector.

Claims (1)

[Claims] 1. A heating element whose outer surface emissivity roughly matches the emissivity of the human skin surface or clothing, a sensing element that detects the temperature of this heating element, and a space provided around the outer periphery of the heating element to ensure uniformity throughout the entire covering. A heat sensing element consisting of a heating element cover made of resin molding such as polyethylene and having a large number of ventilation holes.