JPH023894B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention provides a method for controlling the room temperature of an air conditioner that prevents the feeling of cold air when heating is being performed at a relatively low set temperature (for example, 17 degrees Celsius or lower). This relates to a control method.

"Conventional technology" In general, variable capacity (inverter type) air conditioners increase the operating frequency of the compressor as the difference between the room temperature and the set temperature increases, and decrease the operating frequency when the room temperature approaches the set temperature. to maintain room temperature.

However, with such inverter systems, conventional methods to prevent cold air from blowing out during low-temperature heating are to detect the temperature of the heat exchanger and, when the temperature drops below a certain level (for example, 30°C), turn off the indoor fan. It was supposed to switch to a light breeze or stoppage.

``Problem that the invention seeks to solve'' However, the set temperature of the room temperature is low (for example, 16
℃), the heating load is low, so the compressor operates at the lowest frequency (for example, 30Hz), and the temperature of the heat exchanger also decreases. Moreover, as the set temperature of the room temperature is lower, the outlet temperature also decreases as shown by the dotted line characteristic (A) in Figure 2 compared to the normal set temperature (for example, 21℃), so the outlet air temperature in weak winds decreases. The temperature is only around 30℃, and you often feel a cold breeze. For this reason, conventionally, the cold air prevention function described above operates to create ultra-light air, resulting in an increase in the temperature of the blown air.
However, due to the small amount of airflow, the room temperature distribution deteriorated, resulting in a feeling of cold air, such as cold feet.

"Means for Solving the Problems" The present invention was made to solve the above-mentioned problems, and it changes the operating frequency of the compressor according to the difference between the room temperature and the set temperature. In a variable capacity air conditioner with a minimum operating frequency set, the minimum operating frequency of the compressor when the room temperature setting is low enough to feel a cold breeze is set slightly higher than the minimum operating frequency at the normal setting temperature. This control method prevents the blowout temperature from decreasing.

``Effect'' When the room temperature setting is low, for example 16℃, the lowest frequency of compressor operation becomes slightly higher than when the normal temperature setting (for example 18℃ or higher) is used, which causes the temperature of the blown air to rise and cool air to flow. The feeling disappears.

"Example" Hereinafter, one example of the present invention will be described based on the drawings.

1 is a room temperature detection circuit, 2 is a heat exchanger temperature detection circuit, and these circuits 1 and 2 are each composed of thermistors 3, 4, resistors 5, 6, 7, 8, 9, 10, capacitors 11, 12, etc. has been done. These room temperature detection circuit 1 and heat exchanger temperature detection circuit 2 are coupled to the input side of a microcomputer (hereinafter referred to as microcomputer) 14 via an analog-to-digital conversion circuit (hereinafter referred to as A/D conversion circuit) 13. A remote controller (hereinafter referred to as remote control) 15 for inputting a set temperature is coupled to the other input side of the microcomputer 14. An inverter 16 is connected to the frequency command signal output side of the microcomputer 14, and a compressor 17 is connected to the inverter 16.

In the above configuration, the analog signal of the room temperature (Tr) detected by the room temperature detection circuit 1 and the analog signal of the heat exchanger temperature (Tc) detected by the heat exchanger temperature detection circuit 2 are The conversion circuit 13 converts it into a digital value and sends it to the microcomputer 14 every moment. Further, a signal corresponding to the set temperature (Ts) is sent from the remote control 15 to the microcomputer 14. In the microcomputer 14, the larger the difference between the set temperature (Ts) and the room temperature (Tr), the higher the operating frequency (f).
The inverter 16 is commanded to increase the . Then, the inverter 16 outputs a signal with a corresponding operating frequency (f), and the operation of the compressor 17 is controlled. When the room temperature (Tr) approaches the set temperature (Ts), the operating frequency (f) decreases to maintain the room temperature (Tr) at the set temperature (Ts).

Here, according to the control method of the present invention, the lowest frequency (fmin) is set to 30Hz when the indoor set temperature (Ts) is above a predetermined value (for example, 18℃), but when it is below the predetermined value (for example, 18℃) Set to 40Hz. Therefore, when the indoor temperature setting (Ts) is set to less than 18℃, when the room temperature (Tr) approaches this setting temperature (Ts), the minimum frequency (fmin) becomes 40°C.
It does not drop below Hz. This means that the blowout temperature during operation at the lowest frequency (fmin) becomes higher than before, as shown by the solid line characteristic (B) in FIG. 2, and the cold air feeling disappears.

"Effects of the Invention" As described above, the present invention controls the operation of the compressor so that the lowest frequency of the compressor operation is higher than that at the normal set temperature below a certain set temperature, thereby reducing the blowout temperature. This prevents the feeling of cold air, resulting in more comfortable heating operation.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an air conditioner control circuit for realizing the room temperature control method according to the present invention, and FIG. 2 is a temperature characteristic diagram at the lowest frequency of the compressor. 1... Room temperature detection circuit, 2... Heat exchanger temperature detection circuit, 3, 4... Thermistor, 13... A/D conversion circuit, 14... Microcomputer, 15... Remote control,
16...Inverter, 17...Compressor.

[Claims]

1 In response to indoor load fluctuations, the indoor thermostat sends an opening/closing control signal to the variable air volume machine at the end of the duct, and this variable air volume machine opens and closes to fluctuate the air volume, minimizing the accompanying fluctuations in the static pressure inside the duct. This is a variable air volume method in which an air volume control signal is sent to the blower and exhaust fan to control the blower and exhaust fan, thereby varying the air volume and exhaust volume. An intake air speed sensor that detects the amount of air passing through the supply air and an exhaust air speed sensor that detects the amount of air that passes through the exhaust air are installed at each sufficiently rectified position of the air supply system. A static pressure sensor is provided, and the detection signal from the static pressure sensor sends a supply air volume control signal to the blower to control the rotation speed in order to minimize fluctuations in the static pressure inside the duct, and also controls the supply and exhaust air volume. The upper and lower limit values of the ratio are set in advance, and compared with the current supply/exhaust air volume ratio detected by each wind speed sensor, the rotation speed is controlled so that the current supply/exhaust air volume ratio is within the range of the above set values. A variable air volume method for air conditioning, characterized in that an exhaust air volume control signal is sent to the exhaust fan.