JPH0131103B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an air conditioner that can accurately estimate outdoor temperature indoors using at least indoor humidity.

Conventionally, in separate type air conditioners, an outdoor temperature detector using a temperature sensing element such as a thermistor is installed on the outside wall of the outdoor unit, and the detected amount is used to display the outdoor temperature on the indoor unit, or to display the outdoor temperature in response to the outdoor temperature. The indoor temperature was controlled by

However, such outdoor temperature detectors usually have air circulation holes all over the surface and have a waterproof thermistor placed inside a white-painted case, so they cannot be exposed to direct sunlight, etc. Not only could the effects of thermal radiation not be sufficiently removed, but there was also the drawback that deterioration due to rain and dew, the aforementioned thermal radiation, etc. was severe.

Also, if the thermistor wiring is bundled with the power line, noise from the power line will enter and cause malfunction, so it is necessary to wire it separately.
This also had the disadvantage of requiring a lot of construction work.

The present invention relates to an air conditioner that improves the above-mentioned disadvantages and estimates the outdoor temperature on the indoor side.

FIG. 1 is a block diagram showing an embodiment that is the basis of this invention. In the figure, 10 is an indoor unit, 11 is an indoor heat exchanger (evaporator), 12 is a blower with three speeds: high speed (H), medium speed (M), and low speed (L). Heat exchange is performed between the indoor air blown in the direction of the arrow by the rotation of the blower 12 and the refrigerant supplied to the heat exchanger 11. 20 is an outdoor unit, 21 is an outdoor heat exchanger (condenser), 22 is a two-speed blower of high speed (H) and low speed (L), 23 is an electric compressor that compresses the refrigerant, and 24 is a pressure reducing valve. The heat exchanger 21 exchanges heat between the outdoor air blown by the rotation of the blower 22 and the refrigerant supplied to the heat exchanger 21 . Heat exchanger 11, 21, compressor 2
3. The pressure reducing valve 24 is connected by refrigerant piping as shown in the figure, and is connected to a heat pump type refrigeration cycle (circuit).
form.

31 is an air temperature detector that detects the temperature Tai on the inflow side (inlet side) of indoor air to the heat exchanger 11; 32 is an air temperature detector that detects the temperature Tao on the outflow side (outlet side) of the indoor air to the heat exchanger 11; A temperature sensor is placed in the room air flow and generates an electrical signal depending on the temperature. 3
3 is a refrigerant temperature detector that detects the temperature Tei on the inflow side (inlet side) of the refrigerant to the heat exchanger 11, and 34 is a refrigerant temperature detector that detects the temperature Teo on the outflow side (outlet side) of the refrigerant with respect to the heat exchanger 11. These refrigerant temperature detectors 33, 3
Reference numeral 4 is provided on the pipe wall of the refrigerant pipe near the heat exchanger 11, and generates an electric signal according to the refrigerant temperature. 3
5 receives the outputs of the temperature detectors 31 to 34, calculates and estimates the temperature To of the outdoor air, outputs the value to the outdoor temperature display 36, and uses that value to control the temperature To from the indoor temperature setting device 38. This is an outdoor temperature estimation control device that changes a set value, compares and determines this value with the indoor temperature detected by the air temperature detector 31, and controls operation/stop of the compressor 23.

Next, according to FIG. 6, the outdoor temperature estimation control device 35
(hereinafter abbreviated as the estimation control device) will be explained in detail.
The estimation control device 35 is a microprocessor or the like.
CPU 40 and multiplexer (multi-point switch) 4
1, analog/digital signal converter (A/D converter) 42, input interface 43, output interface 44, memory 45, and relay 4
6, each of the temperature detectors 31, 32,
A constant DC voltage is applied to 33 and 34 via a resistor 31 or the like, and a temperature change is input to a multiplexer 41 as a voltage change. Room temperature setting device 38
is made up of a variable resistor, etc., and a constant DC voltage is applied to both ends of the resistor, and the voltage changes in accordance with changes in its position, and this is also input to one point of the input terminal of the multiplexer 41. Each of the above inputs is switched by a multiplexer 41, converted into a signal one by one by an A/D converter 42, and then sent via an input interface 43.
It is input to the CPU 40. The CPU 40 calculates the outdoor temperature based on these inputs and a predetermined program and data stored in the memory 45, and uses the calculated value to set the room temperature set value by software to follow the estimated outdoor temperature during cooling operation, for example. The set value after the change is compared with the above room temperature, and the relay 46 is activated via the output interface 44.
The compressor 23, which is connected to the power supply 50 through its contacts, is operated and stopped by turning it on and off.

FIG. 7 is a flowchart of the arithmetic and control program, which starts and sets the switching channel of the multiplexer 41 to the first channel in step (60). At step (61), the A/D converter 42
converts the analog signal into a digital signal and sends it to the CPU 40 via the input interface 43.
In step (62), the read voltage is converted into temperature and stored in the memory 45. Step (63) judges the channel (for example, here there are 5 input points, and whether or not all 5 points have been read), and if all reading has not been completed, step (64) is executed.
Switch the channel to the next channel and repeat steps (61) to (63).
Proceeding to the next step (65), the outside air temperature is calculated from the read temperature. In step (66), the set value of the room temperature is changed according to the outside temperature, and in step (67), the set value is compared with the room temperature. For example, if the room temperature during cooling is higher than the set temperature, the process goes to step (68). The compressor 23 is operated, and when the temperature is low, the compressor 23 is stopped at step (69). The above flow is repeated at a predetermined interval time.

Now, the inventor conducted various experiments on the configuration shown in Figure 1, and as a result of correlation analysis, found that the outdoor temperature
We found that To can be calculated and estimated using the following equation. First, when the outdoor fan 22 is operated at high speed (H), To=f(Tai, △Te)≒0.527Tai−1.2
64△Te+21.55……(1) When the outdoor fan 22 is operated at low speed (L), To=f(Tao, △Te)≒0.624Tao−1.1
97△Te+27.04……(2) However, △Te=Teo−Tei.

These equations (1) and (2) are stored in the outdoor temperature estimating device 35, and selected according to the operating state of the blower 22, and from the temperature detectors 31 to 34, Tai,
By providing Tao, Tei, and Teo, the estimation device 35 outputs an electrical signal according to To.

Figure 2 is a chart showing data actually obtained when the indoor humidity is 50%. Note that this data was obtained at an indoor humidity of 50% using a Mitsubishi Electric Corporation MS-2203R air conditioner (standard cooling capacity 2240.0 Kcal/h, 60 Hz). As is clear from this Figure 2, the error between the actual outside air temperature (outdoor air temperature) and the estimated outside air temperature is between 0.1 and
The temperature is 1.5℃, which is sufficiently practical.

FIG. 3 is a chart showing data actually obtained when the indoor humidity is 70%. This data is also for when the same air conditioner as in Figure 2 is used. As is clear from FIG. 3, when the indoor humidity changes to 70%, the error between the actual outside temperature and the estimated outside air temperature is 2 to 9 degrees Celsius, making it difficult to put it into practical use. In order to deal with this problem, the inventor conducted various experiments again and performed correlation analysis, and as a result, was able to obtain the following improved arithmetic expression.

(a) When the indoor fan 12 is operated at high speed (H), To=f(Tai, Tao, △Te, Tao ² , Tei ² )≒72.64+1.43T
ai−9.42Tao−0.317△Te +0.187Tao ² +0.145Tei ² ...(3) (b) When the indoor fan 12 is operated at medium speed (M), To=f(Tai, Teo, △Ta ² , Tei ² )≒86.43−4.128Tai−
0.509Teo+0.188△Ta ² +0.239Tei ² ...(4) However, △Ta=Tao−Tai (c) When the indoor fan 12 is operated at low speed (L), To=f(Tao, Teo, Tei ² )≒93.66−9.79Tao
−0.23Teo+0.543Tei ² ...(5) Equations (3), (4), and (5) are stored in the storage device in the estimation device 35, and they are selected and calculated according to the operating state of the blower 12. .

Now, the actual data when estimated using the above equations (3), (4), and (5) are shown in Figure 4 as estimated outside air temperature (To) ₁
Shown below. This data was obtained using the same air conditioner as in Figure 2. As is clear from (To) ₁ in Figure 4, when formulas (3), (4), and (5) are used, the error from the actual outside temperature is 0.1 to 3.3 (℃), which is sufficient for practical use. Ta.

This invention aims to further improve the estimation accuracy based on the above-mentioned experiment, and examples of the invention will be described below. In this embodiment, as shown in FIG. 5, a resistance-type indoor humidity detector 39 made of, for example, metal oxide ceramic is further installed in the indoor unit 10 on the indoor air suction side of the heat exchanger 11.
is added, which supplies an electric signal to the estimation device 35 according to the relative humidity _i of the indoor air. It has been found that the calculation formula including this relative humidity _i should be as follows.

(a) When the indoor fan 12 is operated at high speed (H), To = f (△Te, e, Tao ² , Tei ² , i) ≒ 58.9 + 0.214
△Te−3.07e+0.047Tao ² +0.089Tei ² −0.185i ……(6) However, e=Tei+Teo/2 (b) When the indoor fan 12 is operated at medium speed (M), To=f(Tai, Teo, Tao ² , i)≒40.2+0.37Tai−1.
0Teo＋0.211Tao ² −0.818i……(7) (c) When the indoor blower 12 is operated at low speed (L), To=f(Tao, Teo, i)≒20.12+6.723Tao−
1.171Teo−0.956i……(8) Estimated temperature (To) from these calculation formulas ₃ to 4th
Shown in (To) ₂ in the rightmost column of the figure. As is clear from this data, when the relative humidity _i is introduced and estimated using equations (6), (7), and (8), the error from the actual outside air temperature is 0.1 to 1.3 (℃), which is more Highly accurate estimation becomes possible.

As described above, according to the device of the present invention that utilizes at least the indoor humidity, it is possible to estimate the outdoor temperature with high accuracy on the indoor side, and it is possible to display the outdoor temperature and control the compressor with a simple configuration.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment that is the basis of this invention; FIGS. 2, 3, and 4 are diagrams showing obtained data; FIG. 5 is a block diagram of an embodiment of the inventive device; FIG. 6 is an electric circuit block diagram of the circuit shown in FIG. 1, and FIG. 7 is a flowchart of the circuit shown in FIG. In the figure, 11 is an indoor heat exchanger, 21 is an outdoor heat exchanger, 23 is a compressor, 24 is a pressure reducing means, 31,
32, 33, and 34 are temperature detectors, 39 is a relative humidity detector, and 35 is an outdoor temperature estimation device. In the figure,
The same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] 1. An indoor heat exchanger for exchanging heat between the refrigerant and indoor air; an outdoor heat exchanger connected to the indoor heat exchanger for exchanging heat between the refrigerant and outdoor air; a temperature detector that detects the air temperature on the indoor air inflow side of the indoor heat exchanger, a temperature detector that detects the air temperature on the indoor air outflow side of the indoor heat exchanger, and a temperature detector that detects the air temperature on the refrigerant inflow side of the indoor heat exchanger. an outdoor temperature estimating device that generates an output signal according to the temperature of outdoor air based on a combination of outputs of a temperature detector that detects the refrigerant temperature on the refrigerant outflow side of the indoor heat exchanger; An air conditioner comprising: an outdoor temperature estimation device for estimating outdoor air temperature based on the outputs of the temperature detectors and the indoor humidity detector; air conditioning equipment.