JPH01296027A - Heating device for air conditioner - Google Patents

Abstract

PURPOSE:To perform proper and reliable control of energization during abnormal generation of heat through the self-temperature control function of a heat generating body and to improve safety and reliability, by a method wherein an organic PTC surface heat generating substance having a positive resistance temperature factor is used as an auxiliary heating source. CONSTITUTION:A substance in which a surface heat generating substance 10 is laminated in a plateform or a spiral state is located as a heating device 11 is juxtaposition on the upper side of the upper side of a heat exchanger 6. Similarly, the surface heat generating substance 10 is laminated as a heating device 12 in a state to be wound around a fan casing 4 of a blower 5. This constitution enables auxiliary heating of air, discharged from an air conditioner, in a proper given state by means of an organic PTC surface heat generating substance 10 incorporated as an auxiliary heating source, and actions so as to reduce production of a fluctuation in an ambient temperature through the self-temperature control function thereof. Even when, during abnormal generation of heat, e.g. failure in operation of the blower 5, a safety device, e.g. a temperature fuse, is not motioned, resistance is increased by a heat peak phenomenon, heat generation is substantially stopped, and safety of and reliability on an air condition are improved.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a heating device for an air conditioner that is incorporated into the internal air passage of an air conditioner housing to supplementally heat the air, and in particular, relates to a heating device for an air conditioner that is incorporated into the internal air passage of an air conditioner housing to supplementally heat the air. Coefficient (Positive Tempera
Organic PT with fura Coefficient)
The present invention relates to a heating device for an air conditioner that improves the safety and reliability of the air conditioner by using a C-plane heating element as an auxiliary heating source.

[Conventional technology]

Conventional heating devices for air conditioners of this type include, for example, a sheathed heater in which a heating wire such as a nichrome wire (not shown) is sealed inside a sheath as shown in FIG. 9(a), and a sheathed heater as shown in FIG. 9(b). As shown, an electric heater (see Japanese Utility Model Publication No. 81-12507, etc.) is known, in which a plurality of electric heater wires are arranged upright. The general structure of an air conditioner using such an auxiliary heater will be briefly explained using Fig. 1θ and Fig. IT.
In the air conditioner housing shown in , an air filter 2 forming a suction port is provided on the lower side of the housing l, and an air filter 2 consisting of a motor 3, a fan 4a, and a fan casing 4 is provided on the upper side of the filter 2. A PIt machine 5 is installed. Furthermore, a heat exchanger 6 is disposed at an angle in the entire space inside the blower 5 so as to block the air path of the intake air, and the lower end of the heat exchanger 5l16 is provided with a cooling and heating device. A drain pan 6a is provided to treat drain generated from the heat exchanger 6 at times. Reference numeral 7 denotes an auxiliary heating device including the aforementioned sheathed heater or electric heater (see FIGS. 9(a) and 9(b)), which is installed in parallel on the upper side of the heat exchanger 6. An air outlet 8 is formed in the upper part of the housing 1 . In the figure, 1a is a front panel, 1b is a back panel, and lc and lc are side panels that form an air passage (air path) 9 together with the two vine panels la and lb.

An air conditioner incorporating the conventional auxiliary heating device 17 has the above-mentioned configuration, and the air is transferred from the filter 2 to the blower 5, the heat exchanger 6, and the auxiliary heating device 7.
Further, the air passes through the air outlet 8 and is blown out to the outside of the housing 1 . At this time, the circulating air is cooled or warmed by the heat exchanger 6, but when the indoor or outdoor air temperature is low during heating operation and the temperature of the air warmed by the heat exchanger s6 is low, the auxiliary heating device 17 is activated. It was designed so that it could be activated to provide heating.

[Problem to be solved by the invention]

By the way, in an air conditioner incorporating the conventional auxiliary heating device W17 such as a sheathed heater or an electric heater as described above, when the blower outlet 8 is a component with a low heat resistance temperature such as a resin molded product, the blower 5 If the wind speed decreases due to failure of the filter 2 or dirt, etc. adhering to the filter 2,
As the surface temperature of the auxiliary heating device 7 increases, the ambient temperature becomes high, which may deform the air outlet 8, which has a low heat-resistant temperature, and in the worst case, there is a risk of ignition, smoke, etc. There is a need for countermeasures that can eliminate these problems.

In order to prevent such overheating of the auxiliary heating device M7,
Conventionally, it has been common practice to attach a safety circuit for temperature control using a temperature fuse or the like to a part of the energizing circuit to the heater, but this increases the complexity of the entire device and requires space for its installation. There are also problems such as the overall size of the air conditioner due to the increase in the size of the air conditioner.Furthermore, countermeasures in the event that such safety circuits do not operate are necessary to ensure the safety and reliability of the air conditioner. , these points must be taken into consideration.

The present invention was made in view of these circumstances, and uses an organic heating element made of an organic PTC material or the like having a positive temperature coefficient of resistance and capable of exhibiting a self-temperature control function. Even if the safety devices installed around the heating element do not operate in the event of an abnormality such as a failure of the blower, the heating element itself will cause a heat peak phenomenon and virtually stop the electricity supply. Air IAI can improve the safety and reliability of air conditioners! The purpose is to obtain a heating device for a 4-way machine.

[i! Means to solve IIM]

The heating device for an air conditioner according to the present invention uses an organic PTC surface heating element with a positive temperature coefficient of resistance as an auxiliary heating source for the air conditioner, and uses the self-temperature control function of the heating element to prevent abnormal heat generation. The structure is such that energization control can be performed appropriately and reliably.

[Effect]

According to the invention, organic PT incorporated as an auxiliary heating source
The C-plane heating element etc. can appropriately auxiliary heat the blown air in the air conditioner, and the heating element's own temperature control function acts to reduce fluctuations in ambient temperature.
Even if safety devices such as temperature fuses do not operate in the event of an abnormality such as a blower malfunction, the heating element itself can become highly resistant due to the heat peak phenomenon and perform the function of stopping heat generation, which improves safety in air conditioners. This can improve performance, reliability, etc.

〔Example〕

Hereinafter, the present invention will be explained in detail using embodiments shown in the drawings.

Figures 1 to 8 show heating v for air conditioners according to the present invention.
cW, and in these figures, the same or corresponding parts as in FIG.

Now, according to the present invention, a surface heating element 1O formed of an organic PTC material having a positive temperature coefficient of resistance is used as an auxiliary heating source for the air in the air conditioner as described above, and the heating element 10 itself is It is characterized by its self-temperature control function, which allows it to appropriately and reliably control energization in the event of abnormal heat generation such as a failure of the blower 5. Here, in FIG. 1, as illustrated in FIGS. 2 and 3, a heat exchanger 6) formed by layering surface heating elements 10 in a plate shape or a spiral shape is used as a heating device 11. : A case in which they are arranged side by side on the −E side of the side surface, and a case in which a similar surface heating element IO is bonded to the fan casing 4 of the blower 5 as the heating device 12 in a state where it is wound around it are both shown.

According to such a configuration, the PTC surface heating element 10 incorporated as an auxiliary heating source can appropriately auxiliary heat the air blown out from the air conditioner in the state of fresh snow, and the surface heating element 10 itself can The self-temperature control function works to reduce fluctuations in ambient temperature, and in the event of abnormal heat generation such as a failure of the blower 5, safety devices such as a temperature fuse (
(not shown) does not operate, this heating element l
O itself has the advantage of increasing resistance due to the heat peak phenomenon and exhibiting the function of virtually stopping heat generation.
This can improve the safety and reliability of air conditioners. That is, an organic heating element 10 in which carbon black is dispersed in a polymer as described below has an exothermic temperature of 10
It has a self-temperature control function because it has a low temperature of 0°C or less and a positive temperature coefficient of resistance. It also has a self-temperature fuse function in which a heat peak phenomenon occurs when the input power becomes excessive, irreversibly increasing the resistance, making it excellent in safety and reliability. Therefore, by employing such a heating element 10 in an air conditioner, even if a safety device as an electric circuit (temperature fuse, etc.) does not operate.

The heating element itself exhibits a self-temperature control function, and in the event of an overload, the self-temperature fuse function stops the heating element from functioning as a heat source, making it possible to use it as an extremely safe heat source.

To elaborate on this, organic PT with a positive temperature coefficient of resistance
As shown in FIG. 6, the C-plane heating element IO has a property that as the heat generation temperature (surface temperature) of the heating element increases, the specific electrical resistance of the heating element also increases.

Its specific electrical resistance (ρ) is expressed by the following formula.

ρ= /) O(t+ezpK (T-Tc))
Here, T is the exothermic temperature, and Tc is the transition temperature (5 in Figure 6).
0°C), K is the temperature coefficient of resistance, and ρG is a constant value at which the specific electrical resistance asymptotes at the heating temperature below Tc (~10°C in Figure 6).
2Ωcm).

In this Figure 6, the resistance temperature coefficients of characteristic curves ■ to ■ are as follows:
0.4, 0.8, 0.8, 1.0 and 1 respectively
．． 2 1/”O, and the larger the temperature coefficient of resistance.

This means that it has excellent PTC characteristics.

Further, the current heating characteristics of such @PTC surface heating element IO are shown in FIG. In other words, if the ambient temperature is -2
It represents the results of measuring the heat generation temperature of the heating element while varying it in the range of 0°C to 40°C, and the characteristic i! 1(I) and (II) have resistance temperature coefficients of 1.0 and 0.0, respectively.
4, and the characteristic curve (III) represents the case where the temperature coefficient of resistance is 0, that is, the heating element does not have PTC characteristics.As is clear from this FIG. It can be said that it has a self-temperature control function, with little change in heat generation temperature due to fluctuations. On the other hand, organic P
If the TC surface heating element lO supplies too much power.

The balance between heat generation and heat radiation or heat diffusion is disrupted, creating a high temperature area near the center between the electrodes. Because high-temperature parts have high resistance due to PTC characteristics, more Joule heat (ilR) is generated than other parts, and a positive feedback effect occurs in which the temperature becomes even higher, eventually causing heat to partially melt the matrix. A peak phenomenon occurs. Figure 8 shows a matrix of polyethylene with a softening temperature of 110 degrees, carbon black as a conductive filler, and a distance between electrodes of 3 degrees.
? A, B, and C in the same figure show the results of measuring the maximum input power just before the heat peak occurs when an organic PTC surface heating element IO of 10 cm in length is placed in a thermostatic chamber and energized.
and D show characteristics corresponding to inter-electrode distances of 3.5.7 and 10c. As is clear from this characteristic diagram, the maximum input power decreases as the ambient temperature increases, and the softening of the matrix It was confirmed that the value becomes 0 when the temperature is around 110 degrees. Therefore, this maximum input power increases as the distance between the electrodes becomes smaller, as it becomes easier to dissipate heat. For example, when a heating element with a distance between the electrodes of 3C is placed in a thermostat at 20°C and energized, it is approximately 5KW/m! A heat peak phenomenon occurred at an input power of This heat peak phenomenon functions as a self-temperature fuse, which is a huge advantage in ensuring safety. In other words, when an organic PTC surface heating element IO using a base polymer with a softening temperature of ~110°C is used as an auxiliary heating source for an air conditioner, if the heat generation temperature of the heating element rises for some reason, the air conditioner will normally be turned off. Safety devices such as a temperature fuse installed on the machine operate, but in the event that the temperature fuse and other safety devices do not operate, this heating element 1
0 itself causes a heat peak phenomenon, becomes high in resistance, and stops generating 1 heat, resulting in it operating as an extremely safe heating element.

In particular, such a heat peak phenomenon occurs when the P of the heating element 10
This is caused by the TC characteristics, and the higher the positive temperature coefficient of resistance, the more likely it is to occur. This positive temperature coefficient of resistance is a characteristic value determined by the amount of carbon, which is the conductive filler, and the base polymer, which is the matrix, but it functions satisfactorily as long as it is at least 0.81/''C or higher. As the organic PTC surface heating element 1O, a thermoplastic polymer having a softening temperature of 100 to 160°C is preferably used, for example, polyolefin such as polyethylene or polypropylene is suitable.In addition, as the conductive filler, in addition to carbon, Fine fibers of carbon or metal are also used for this purpose, but carbon black is preferred to ensure a high temperature coefficient of resistance.In addition, organic compounds with a low melting point are used as a tertiary material to control the self-temperature control function. Although it is added as a component, a polyolefin wax such as a low molecular weight polyethylene wax is suitably used.

Based on these results, for example, a composition in which 20 to 30% by weight of carbon is mixed with a base polymer,
After uniformly kneading with a Banbury mixer etc., it is preferable to extrude from a T-die to produce a sheet-like surface heating element.
In addition, if necessary, add 20 to 30% of low molecular weight polyethylene.
The PTC characteristics of the surface heating element manufactured in this way depend on the composition, crosstalk, and extrusion molding conditions, but it is easy to add one with a positive temperature coefficient of resistance of 0.8 17"C or more. It can be manufactured in

In addition, the width of the surface heating element IO manufactured in this way is 5
5 (a) and (b) using the electrolytic copper foil 13 of No. 11 as an electrode.
) As shown in Figure 8, the smaller the distance between the electrodes, the greater the maximum input power can be obtained, but the cost will be higher. In this example, a 5c model was manufactured. Furthermore, in order to provide electrical insulation, the heating element on the surface of the electrode material was sandwiched between polypropylene films with a thickness of 12 mils.

It is best to heat-seal the ends to produce a band-shaped heater.Such a heater structure is laminated in a plate or spiral shape with a corrugated separator, as shown in Figure 2 or Figure 3. It is good to use it as an air conditioner mJWi heat device. In addition, in these figures, the reference numeral 14 is a heater constituting the heating device 11.
Further, numeral 15 represents a corrugated separator for ensuring an air passage, but FIG. 2 shows a case where this separator 15 is omitted.

In addition, such an organic PTC surface heating element 10 causes a heat peak phenomenon due to the PTC characteristics when a temperature distribution occurs inside the heating element as described above. By bonding these together, it is possible to suppress the occurrence of temperature distribution to some extent. As a result, the occurrence of heat peaks can be suppressed more than necessary, and the life of the heater can be extended.

Further, according to the above-described organic PTC surface heating element 10, it can also be used by bonding it to the fan casing 4 of an Arshirocco fan using an air blower 115, as shown in FIGS. 1 and 4. and.

With such a configuration, the metal fan casing 4
Since the heating element functions as a heat equalizing plate, the life of the heating element is extended, and the heating element is placed in the airflow, so the efficiency of heat dissipation is high. It has the advantage that it does not require space and can be easily used as a compact heating source.

Note that the present invention is not limited to the structure of the above-described embodiments, and the shape, structure, etc. of each part of the heating device, including the air conditioner, may be modified and changed as appropriate, and various modifications may be considered.

〔Effect of the invention〕

As explained above, according to the heating device for an air conditioner according to the present invention, an organic PTC surface heating element having a positive temperature coefficient of resistance is used as an auxiliary heating source for the air conditioner, and the self-temperature of the heating element is The control function is configured to appropriately and reliably control energization in the event of abnormal heat generation, so despite the simple and inexpensive configuration, the surface heating element built in as an auxiliary heating source can be used as the required auxiliary heating source. While ensuring the function, the self-temperature 1tJI control function of this heating element itself acts to reduce fluctuations in ambient temperature, even if safety devices such as temperature fuses do not operate in the event of abnormal heat generation such as a blower failure. However, this heating element itself has a high resistance due to the heat peak phenomenon and generates heat! Since the function of stopping the air conditioner can be exhibited qualitatively, there are various excellent effects such as the ability to significantly improve the safety and reliability of the air conditioner compared to conventional ones.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram of an air conditioner showing an embodiment of heating 1Jtll for an air conditioner according to the present invention, and Figs. Figures 5(a) and 5(b) are diagrams for explaining the configuration of the heating element, and Figures 6 to 8 are characteristic diagrams showing the PTC characteristics, self-temperature control function, and current heating characteristics, respectively. , flS9 figure (a). (b) is a schematic diagram showing two auxiliary heating devices used for conventional air conditioners, and Figures 1O and 11 are conventional auxiliary heating devices! FIG. 2 is a side cross-sectional view of main parts and a front view with the front panel removed, showing a schematic configuration of an air conditioner employing the EIT. l...Air conditioner housing, 2...Air filter,
4...Fan casing, 5...Blower, 6...
... Heat exchanger, 8... Air outlet, 9... Air passage (air path), lO... Organic heating element (organic PTC surface heating element), 11.12... heating device.

Claims (1)

[Claims] In a heating device for an air conditioner that is disposed in an air path in an air conditioner housing to auxiliary heat the air, an organic heating element having a positive temperature coefficient of resistance is used as an air auxiliary heating source in the air path. Heating for an air conditioner, characterized in that the self-temperature control function of the heating element is configured to substantially stop energization due to the heat peak phenomenon of the heating element itself during abnormal operation due to failure of the blower, etc. Device.