JP2003161501A - Control method of air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the dew condensation on the surface of equipment to be cooled even when stopping the operation of a compressor because air conditioning machine intake air temperature reaches a set temperature by automatically detecting an air conditioning load even if it is extremely low. <P>SOLUTION: When the air conditioning load is extremely low, an indoor machine fan is stopped. The tendency of dew condensation on the equipment to be cooled is automatically detected to prevent the dew condensation. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner control method and a load detection method when the air conditioning load is extremely low.

[0002]

2. Description of the Related Art Originally, an air conditioner is intended to cool air, and employs a control method for cooling it as quickly as possible. For some special purpose air conditioners, there are some products that use a temperature sensor and a humidity sensor to make the temperature of the blown air constant, but for general air conditioning, it is controlled so that it cools rapidly at startup.

[0003]

In a normal use environment for personal use, the air conditioning function and the air conditioning load are balanced to some extent, and when the air conditioner is operated, some continuous operation can be expected. On the other hand, in the case of objective air conditioning, the air conditioning function is determined according to the maximum load of the target heat load, so when the target load is significantly reduced, the operating time of the air conditioner will be shortened significantly, resulting in drainage. As a result, dehumidification occurs in the indoor installation equipment when the thermostat is turned off because the indoor humidity is high even after a lapse of time because the indoor dehumidification cannot be performed.

Therefore, one of the objects of the present invention is to provide a method for detecting an extremely low load.

Another object of the present invention is to provide a control method for preventing the occurrence of dew condensation when the environment is extremely low and the thermostat is turned off.

[0006]

According to the present invention, there is provided control for stopping the indoor unit fan or making a slight breeze during thermo-off under extremely low load conditions.

Further, according to the present invention, there is provided a method for detecting an extremely low load based on the operating time of an air conditioner.

[0008]

According to the present invention, if the operating time of an air conditioner is within a fixed time or if the decrease in the intake air temperature of the air conditioner is below a fixed rate, it is judged that the air conditioning load is extremely low.

Further, when it is determined that the air conditioning load is extremely low, the operation of the indoor unit fan during the thermostat is stopped or stopped by a slight breeze to eliminate the re-humidification of the moisture adhering to the indoor unit heat exchanger, and to dehumidify the room. coming out. (Embodiment 1) An embodiment of objective air conditioning is shown in FIG. Generally, the air conditioner installation room 3 is designed based on the space for the air conditioner 1 to be installed in the cooling target device 2 and its cooling, so that the size of the room is the cooling capacity of the air conditioner 1. Is often narrow. Therefore, the air 6 blown out from the air conditioner 1 directly hits the equipment 2 to be cooled, and the surface temperature thereof is overcooled with respect to the room air temperature. When the temperature detected by the intake air temperature sensor 4 reaches the set temperature of the air conditioner 1, the operation of the compressor is stopped, but if the device to be cooled 2 generates sufficient heat and the air conditioning load is appropriate, the operating time of the air conditioner 1 Since the drain becomes longer and the drainage is discharged to the outside of the air conditioner installation room 3, the absolute air humidity inside the air conditioner installation room 3 decreases, and even when the thermostat is turned off, the dew point temperature of the air inside the air conditioner installation room 3 becomes low. However, dew condensation does not occur on the surface of the cooling target device 2.

However, when the calorific value of the equipment 2 to be cooled is extremely small, the operating time of the air conditioner 1 also becomes extremely short, and the drain of the air conditioner 1 cannot be exhausted to the outside of the air conditioner installation room 3. Generally, during this period, the indoor unit fan 7 continues to operate, so that the moisture inside the air conditioner 1 is re-evaporated and the blown-out air 6 becomes air with high humidity and close to room temperature.

In such a state, the surface temperature of the equipment 2 to be cooled has its heat capacity, so that the temperature changes slowly and remains cooled with respect to the ambient air. Since the humid air at room temperature blows on it, dew condensation occurs when the surface temperature of the cooling target device 2 is lower than the dew point temperature of the blown air 6.

Therefore, the control method shown in the flow chart of FIG. 2 prevents dew condensation during the thermostat is off. Air conditioner 1
If the operating time is within 5 minutes, the air conditioning load in the air conditioner installation room 3 is extremely small, and it is determined that the load is extremely low, and the process proceeds to the dew condensation prevention control 11. In the dew condensation prevention control 11, the indoor unit fan 7 of the air conditioner 1 is stopped while the thermostat is off.
In the next compressor operation, the temperature of the blown air 6 of the air conditioner 1 is controlled to be higher by setting the compressor operation frequency to the lower limit.

Here, by stopping the indoor unit fan 7, the air in the air conditioner installation room 3 stays, and it becomes difficult to grasp the room temperature change status during thermo-off. Therefore, if the installation position of the intake air temperature sensor 4 is moved to the vicinity of the cooling target device 2, the uneven distribution of temperature in the air conditioner installation room 3 can be eliminated. Alternatively, although the effect of preventing dew condensation is weakened, if the indoor unit fan 7 during thermo-off is not stopped but is operated in a slight breeze, it is easy to grasp the room temperature condition.

However, if the compressor operating time is 5 minutes or more during the operation of the dew condensation prevention control 11, the equipment to be cooled 2
Normal air conditioner control 10
Move on to. (Embodiment 2) In (Embodiment 1), whether or not the air conditioning load is an extremely low load was judged by the operating time of the air conditioner 1, but it means to prevent condensation on the equipment 2 to be cooled more severely. Then, there is a flowchart of FIG. According to this, even if the device surface dew point sensor 5 in FIG. 1 detects dew condensation even when the air conditioner operating time is 5 minutes or more, the process immediately shifts to the dew condensation prevention control 18.

[0015]

As described above, according to the present invention, even if the air-conditioning load is extremely low, it can be detected to prevent dew condensation on the surface of the equipment to be cooled when the thermostat is turned off.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of an objective air conditioning system to which the present invention is applied.

FIG. 2 is a diagram showing an embodiment of a flowchart of the present invention.

FIG. 3 is a diagram showing another embodiment of the flowchart of the present invention.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kazuyuki Kuroyanagi             Hitachi, Ltd. 390 Muramatsu, Shimizu City, Shizuoka Prefecture             Air conditioning system Shimizu Production Headquarters (72) Inventor Yoshitaka Fujimoto             Hitachi, Ltd. 390 Muramatsu, Shimizu City, Shizuoka Prefecture             Air conditioning system Shimizu Production Headquarters F term (reference) 3L060 AA07 CC08 CC19 DD01 DD02                       EE02 EE05

Claims (6)

[Claims] 1. A means for automatically detecting the magnitude of an air conditioning load by measuring the operating time of an air conditioner. 2. When the room temperature reaches a set temperature and the compressor stops when the air conditioning load is very small (hereinafter referred to as "thermo off"), the indoor unit fan is stopped and the indoor unit blown air temperature is adjusted when the compressor is restarted. A control method that changes the wind direction by lowering the compressor frequency to the lower limit to raise it. 3. When the thermostat is turned off when the air conditioning load is very small, the indoor unit fan is made to have a slight airflow, and when the compressor is restarted, the compressor frequency is lowered to the lower limit so as to raise the indoor unit blown air temperature, and the wind direction is changed. Control method. 4. The control for stopping the indoor unit fan when the thermostat is turned off when the air conditioning load is very small, and for lowering the compressor frequency to the lower limit so as to raise the temperature of the indoor unit blowing air when the compressor is restarted, and changing the wind direction. Method. 5. When the temperature of air blown out of the air conditioner falls below the set temperature of the dew point sensor when the thermostat is turned off, the indoor unit fan is stopped and the compressor frequency is set to increase the temperature of air blown out of the indoor unit when the compressor is restarted. Is a control method in which the wind direction is changed to the lower limit. 6. When the temperature of air blown out of the air conditioner falls below the set temperature of the dew point sensor when the thermostat is turned off, the indoor unit fan is made to have a slight air flow, and when the compressor is restarted, the temperature of the air blown out of the indoor unit is increased so as to be high. A control method that lowers the frequency to the lower limit and changes the wind direction.