JPH07174440A - Defrost controller for air conditioner - Google Patents

Abstract

PURPOSE:To eliminate a refrigerant flowing sound to an indoor unit side and to shorten an interrupting time of heating by varying a period of time to switching a four-way valve to a heating operating side in response to a pressure difference of a high pressure and a low pressure at the time of finishing a defrosting operation. CONSTITUTION:An operation of a compressor 1 is stopped, a four-way valve 2 is switched to defrosting and the compressor is operated by a controller 6 according to decision of frosting. High temperature and high pressure refrigerant from the compressor is fed to an outdoor heat exchanger 5 to defrost the exchanger 5, refrigerant cooled by heat exchanging is pressure-reduced by a capillary tube 4, and returned to the compressor through an indoor heat exchanger 3 and the valve. A current value of the compressor at the time of finishing the defrosting is detected by a current detector 8, an OFF time of the compressor before the valve is switched corresponding to the current value is read from a memory 9, and this time is counted by a timer 7. The valve is switched to heating upon finishing of the counting, and the operation of the compressor is restarted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat pump type air conditioner, which reduces a switching noise of a four-way valve at the end of defrosting.

[0002]

2. Description of the Related Art When a four-way valve is switched to defrost frost attached to an outdoor heat exchanger during heating operation of a heat pump type air conditioner and to return to heating operation at the end of defrosting operation, high pressure side and low pressure side Due to the pressure difference between the two sides, the refrigerant abruptly flows into the low pressure side, that is, the indoor unit side, so that annoying refrigerant inflow noise is generated. Conventionally, in order to reduce this annoying refrigerant inflow noise,
For example, a time period is provided between the end of the defrosting operation and the switching of the four-way valve, and the four-way valve is switched when the pressure difference becomes small. Therefore, the rest time of heating is the time required for defrosting plus the time for reducing this pressure difference. This increases the number of operation pauses, which is an obstacle to comfortable heating operation.

[0003]

By the way, the defrosting operation time is set in consideration of the case where a lot of frost is formed, but the time actually required for defrosting may be shorter than the set time. In such a case, so-called "color defrosting" is performed in which the defrosting operation continues even after the defrosting ends, and the high pressure pressure of the refrigerant increases due to this color defrosting. This high pressure is
There is a proportional relationship with the current value of the compressor at the end of the defrosting operation.
The present invention focuses on this point, from the end of the defrosting operation to the four-way valve switching according to the current value of the compressor at the end of the defrosting operation so that the refrigerant inflow noise into the indoor unit does not occur due to the switching of the four-way valve. The purpose of this is to vary the time of, so that the downtime of heating operation can be shortened as much as possible, and comfortable heating can be performed.

[0004]

In order to solve the above problems, the present invention forms a refrigeration cycle by sequentially connecting a compressor, a four-way valve, an indoor heat exchanger, a capillary tube, and an outdoor heat exchanger, Cooling, heating, and defrosting operation are performed by switching the four-way valve, and a four-way valve switching corresponding to the current detection unit that detects the current value of the compressor and the current value of the compressor at the end of the defrosting operation A defrosting control device for an air conditioner is configured by a memory unit that stores data on standby time and a control unit that operates the compressor based on the data from the memory unit and switches the four-way valve to heating operation.

[0005]

With the above construction, the defrosting control device for an air conditioner according to the present invention detects the current value of the compressor at the end of the defrosting operation and heats the four-way valve in accordance with this current value. Change the time to switch to.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a defrosting control device for an air conditioner according to the present invention will be described in detail below with reference to the drawings. FIG. 1 is a main part of a refrigerant circuit and a control circuit showing an embodiment of a defrost control device for an air conditioner according to the present invention. In the figure, 1
Is a compressor, 2 is a four-way valve, 3 is an indoor heat exchanger, 4 is a capillary tube, 5 is an outdoor heat exchanger, 6 is a control unit, 7 is a timer for measuring defrosting operation time, and 8 is a compressor. A current detection unit for detecting the current value of 9 is a memory unit for storing the current value of the compressor at the end of the defrosting / defrosting operation and the data of the compressor off time before switching the four-way valve corresponding to each current value. .

During the heating operation, the refrigerant compressed to a high temperature and high pressure by the compressor 1 passes through the four-way valve 2 which is switched to "heating" by the signal from the control unit 6 and enters the indoor heat exchanger 3 as shown by the solid arrow. The indoor heat exchanger 3 exchanges heat with the air sucked from the room by the indoor fan. The refrigerant cooled by this heat exchange is decompressed by the capillary tube 4, vaporized and enters the outdoor heat exchanger 5, exchanges heat with the outdoor air by the blowing of the outdoor fan, passes through the four-way valve 2, and passes through the compressor. It circulates in the route returning to the suction side of 1.

The control unit 6 determines the start of defrosting operation based on, for example, the cumulative heating operation time of the compressor 1 and the difference between the indoor heat exchanger temperature and the indoor temperature. Then, as shown in the time chart of FIG. 2, the control unit 6 stops the operation of the compressor 1 (), and after a predetermined time elapses (), the four-way valve 2 is switched to "defrost" to start the operation of the compressor 1. Then defrost. By this operation, the high-temperature and high-pressure refrigerant from the compressor 1 passes through the four-way valve 2 and is sent to the outdoor heat exchanger 5 as indicated by a dotted arrow, causing the outdoor heat exchanger 5 to generate heat and defrosting. The refrigerant that has been heat-exchanged and cooled in the outdoor heat exchanger 5 is decompressed by the capillary tube 4, returns to the suction side of the compressor 1 via the indoor heat exchanger 3 and the four-way valve 2.

At the defrosting end time measured by the timer 7 (), the operation of the compressor 1 is stopped by a signal from the control unit 6. At this time, the current value immediately before the compressor 1 is stopped is detected by the current detection unit 8, the control unit 6 reads the data of the off time “a” corresponding to the current value from the memory unit 9, and the timer 7 is used. Timekeeping. Then, when the time “a” has elapsed (), the four-way valve 2 is switched to “heating” and the compressor 1 is started. For example, when the current value of the compressor at the end of defrosting is "7 amps or less", the time "a" is the off time of the compressor before switching the four-way valve to "20", as in the example shown in FIG. Seconds "," 7 amps-10 amps "for" 40 seconds "," 10 amps-12 amps "for" 1 "
"Minute" and "12 amps or more" are preset and stored such as "1 minute 30 seconds".

That is, if the current value of the compressor 1 at the end of the defrosting operation is small, the time from the end of the defrosting operation to the restart of the heating operation is short, and if the current value of the compressor 1 at the end of the defrosting operation is large, the heating is performed. Increase the time before restarting operation. This means that the current of the compressor 1 at the end of the defrosting operation is large,
This indicates that “color defrost” was performed even after the defrosting was completed, and the high pressure is increased due to the “color defrosting”. Therefore, the switching of the four-way valve 2 is delayed and the refrigerant to the indoor unit is delayed. This is to prevent inflow noise. In the example shown in FIG. 2, since the current value at the time'is larger than the current value of the compressor 1 at the time, the time'a 'is longer than the time'a'.

[0011]

As described above, according to the defrosting control device for an air conditioner according to the present invention, the heating operation is restored depending on the magnitude of the pressure difference between the high pressure side and the low pressure side at the end of the defrosting operation. Since the time until switching the "heating" of the four-way valve for is changed, it is possible to shorten the downtime of the heating operation within the range where no annoying refrigerant inflow noise to the indoor heat exchanger is generated, and comfortable heating can be performed. It is especially effective when the outside air temperature is low.

[Brief description of drawings]

FIG. 1 is a diagram of a refrigerant circuit and a control circuit showing an embodiment of a defrost control device for an air conditioner according to the present invention.

FIG. 2 is a time chart for explaining the time from the end of the defrosting operation to the return to the heating operation.

FIG. 3 is an example of data showing the relationship between the current value of the compressor at the end of the defrosting operation and the off time of the compressor before switching the four-way valve.

[Explanation of symbols]

 1 Compressor 2 Four-way valve 3 Indoor heat exchanger 4 Capillary tube 5 Outdoor heat exchanger 6 Control unit 7 Timer 8 Current detection unit 9 Memory unit

Claims (2)

[Claims] 1. A refrigeration cycle is formed by sequentially connecting a compressor, a four-way valve, an indoor heat exchanger, a capillary tube, and an outdoor heat exchanger, and cooling, heating, and defrosting operations are performed by switching the four-way valve. The current detection unit for detecting the current value of the compressor, the memory unit for storing the data of the four-way valve switching standby time corresponding to the current value of the compressor at the end of the defrosting operation, and the memory unit A defrosting control device for an air conditioner, comprising: a control unit that operates the compressor based on data and switches the four-way valve to a heating operation. 2. The current value of the compressor at the end of defrosting is divided into a plurality of sections and the four-way valve switching standby time is stored in the memory section in association with each other. Defrost control device for air conditioner.