JPS6166037A - Defrosting control unit of air conditioner - Google Patents

Abstract

PURPOSE:To make it possible to carry out a sufficient space heating operation from the time of starting the operation in any case by determining a defrosting operation time by comparing the temperature of outdoor atmosphere and the temperature of an outdoor heat exchanger with a set temperature at the time of finishing the space heating operation thereby to carry out an operation finish defrosting operation. CONSTITUTION:Firstly, an operation time from the operation starting or the defrosting operation finishing is integrated. When an operation stop signal of the air conditioner is input, a heat exchanger temperature T1 and an external air temperature T2 are detected by a temperature detector 7 and an external temperature detector 8 of a heat exchanger 5. In this case, when the external air temperature T2 is of a value greater than a set temperature Ta which is greater than 0 deg.C, the operation is finished as it is. When the external air temperature is 0 deg.C or less, a required defrosting operation time tD is determined from the relationship between the integrated operation time and the frosting amount, and the mode of the operation enters a defrosting operation. In a case where the external air temperature T2 is 0 deg.C or more and less than the set temperature Ta, when the heat exchanger temperature T1 is 0 deg.C or less, a blower 6 is operated by a time (t) in accordance with the integrated operation time to remove frost at the external air temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an air conditioner that performs heating operation using an air source heat pump.

Configuration of conventional example and its problems Conventionally, this type of air conditioner has a compressor 1, a four-way switching valve 2, an indoor heat exchanger 3, a pressure reducing device 4,
and an outdoor heat exchanger 5 respectively.

During cooling, the four-way switching valve 2 is switched to connect the compressor discharge circuit a to the outdoor heat exchanger 5.
, connect the compressor suction circuit a2 to the indoor heat exchanger 3,
It performs indoor cooling operation using the well-known endothermic action, and during heating,
Switch the four-way switching valve 2 so that it is in the opposite direction during cooling,
Heating operation can be performed using the well-known heat dissipation function. In such an air heat source type heat pump, when the outdoor temperature drops during heating operation, frost grows on the surface of the outdoor heat exchanger 5 and the heating capacity decreases. A defrosting operation is performed in which the temperature of the outdoor heat exchanger 5 is detected and the cumulative operating time is used to perform a temporary cooling operation during the heating operation to melt 117 of the outdoor heat exchanger 5, and then the heating operation is performed again. For example, after heating operation has been performed for one hour (heating operation is performed even when compressor 1 is stopped due to room temperature control), the temperature of outdoor heat exchanger 5 is detected, and if the temperature is below the set temperature, control is performed to perform defrosting operation. I am using it.

Here, if you stop the heating operation immediately before the defrosting operation and start the heating operation again (for example, stop the operation before going to bed and start the heating operation again the next morning), if the outside temperature is 0°C.
In the following cases, the frost from the previous operation remains in the heat exchanger 5, the capacity decreases significantly during the next operation, and sufficient heating operation cannot be performed, or the defrosting operation time performed at the start of operation is too long. It had some drawbacks, such as being long.

OBJECTS OF THE INVENTION The present invention is intended to solve the above-mentioned problems, and it is an object of the present invention to enable sufficient heating operation from the start of operation in any case.

Structure of the Invention In order to achieve this object, the present invention provides a temperature detection device for detecting the outdoor temperature and a heat exchanger temperature detection device, so that after an air conditioner operation stop signal is input, the outdoor temperature is set to the set temperature. The defrosting control device performs defrosting operation when the temperature is lower than that of the heat exchanger, and changes the defrosting operation depending on the comparison between the temperature of the heat exchanger and the set temperature.

With this configuration, it is possible to determine the situation when the heating operation is stopped and perform the defrosting operation so that no frost remains on the outdoor heat exchanger when the heating operation is stopped.

DESCRIPTION OF THE EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 2 to 6.

First, the configuration of the air conditioner will be explained with reference to FIG. It should be noted that the same parts as in FIG. 1 are given the same numbers and their explanations will be omitted.

In the figure, 7 indicates a heat exchanger temperature detection device, and 8 indicates an outside air temperature detection device. Further, FIG. 3 shows a block diagram of control in the configuration of FIG. 2.

As shown in the same control block diagram, the defrosting control device receives information from the outdoor heat exchanger temperature detection device #7 and the outside temperature sensor 8, and the microcomputer 9 determines that the defrosting signal is sent after the operation ends. The defrost control circuit performs defrosting operation for the required time.

In other words, it is necessary to detect the heat exchanger temperature T and the outside air temperature T2 by the heat exchanger temperature detection device 7 and the outside air temperature detection device 8 at the same time as the operation switch of the air conditioner is turned off, and to defrost the operation after the operation is stopped. It is determined whether or not the operation is completed, and the operation time for defrosting is determined, and defrosting operation is started. At this point, the indoor and outdoor blowers 6 are stopped, the four-way switching valve 2 is switched to the cooling cycle/off side, and the compressor 1 is in continuous operation. After the defrosting operation time has elapsed after the completion of the A rotation, all operations are stopped.

Next, specific operation control will be explained with reference to the control flowchart shown in FIG.

First, the operating time from the start of operation or the end of defrosting operation is accumulated. When the air conditioner operation stop signal is input, the heat exchanger temperature T1 and the outside air temperature T2 are detected. First, the outside air temperature T2 is determined, and if the outside air temperature is equal to or higher than the set temperature Ta, which is higher than 0°C, the operation is immediately terminated. Moreover, when the outside air temperature T2 is 0° C. or lower, it is determined that the outdoor heat exchanger 5 is frosted and that a defrosting operation is necessary. Here, FIG. 5 shows the relationship between the cumulative operating time and the amount of frost formation. That is, if the operation is started or the defrosting operation is ended at time O, there is no significant frost growth until the time O, and no defrosting operation is required. Still, FIG. 6 shows the relationship between the cumulative operating time and the required defrosting operating time tD. Defrosting operation is not required until time I, and after time 1, defrosting operation is required at defrosting operation time tD as shown in the figure.

Next, when the outside air temperature T2 is greater than or equal to 0°C and less than or equal to the set temperature Ta, the heat exchanger temperature T1 is determined, and the heat exchanger temperature T1 is
When the temperature is below 'C, there is no need to operate the blower 6 during clearing operation.

Therefore, even if the outdoor heat exchanger 5 is closed at the end of operation, no frost remains, and therefore sufficient heating capacity can be obtained at the start of operation.

Effects of the Invention As described above, the present invention determines the defrosting operation time by comparing the outside air temperature and the temperature of the outdoor heat exchanger with the set temperature at the end of operation of an air conditioner that performs heating operation using an air heat pump. This is a defrosting control for air conditioners that performs end-of-operation defrosting operation, and since defrosting can be reliably performed at the end of operation, sufficient heating capacity can be obtained at the start of the next operation, reducing startup time. The performance of the heater can be greatly improved, such as by providing a good heating feeling. Furthermore, since the defrosting operation is performed only when necessary, wasteful power consumption is prevented, and it can be realized with a simple configuration, which has many advantages.

[Brief explanation of drawings]

Fig. 1 is a refrigeration cycle diagram showing a conventional example, Fig. 2 is a refrigeration cycle diagram showing an embodiment of the present invention, Fig. 3 is a control block diagram of the same, Fig. 4 is a control flow diagram of the same, and Fig. 5 is an integration diagram. FIG. 6 is a characteristic diagram showing the relationship between the operating time and the amount of frost formation, and FIG. 6 is a characteristic diagram showing the relationship between the cumulative operating time and the required defrosting operating time. 1... Compressor, 2... Four-way switching valve, 3
... Indoor heat exchanger, 4 ... Pressure reduction device, 5
... Outdoor heat exchanger, 6... Outdoor blower, 7 ・
- Heat exchanger temperature detection device, 8... Outside temperature detection device. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure 3 Figure 4

Claims (1)

[Claims] A refrigerant circuit consisting of a compressor, a four-way switching valve, an outdoor heat exchanger, an indoor heat exchanger, etc., a heat exchanger temperature detection device that detects the temperature of the outdoor heat exchanger, and an outside temperature detection device that detects the outside temperature. and a defrost control device that controls defrosting operation of the outdoor heat exchanger, and the defrost control device controls the temperature detected by the heat exchanger temperature detection device and the outside temperature detection device and a preset temperature. After the air conditioner operation stop signal is input, a defrosting operation is performed when the outside temperature is lower than the set temperature, and the detected temperature from the heat exchanger temperature detection device is compared with the set temperature. A defrosting control device for an air conditioner configured to have different operating methods.