JPS62255749A - Defrosting operation control device for air conditioner - Google Patents

Abstract

PURPOSE:To reduce a defrosting time in a heat pump type air conditioner by a method wherein an outdoor unit is defrosted if a defrosting start signal is already produced when a disired temperature is attained under a heating operation just after the defrosting operation is completed with a defrosting time-up signal. CONSTITUTION:If a condition setting change-over switch 24 is set at a defrosting wait timer 16, a defrosting thermostat 15 is turned on and a defrosting wait timer 16 is set. A defrosting operation circuit 18 and a timer 17 are operated after the timer 16 is timed up and then the defrosting is carried out. After the defrosting time is elapsed, the operation circuit 18 and the defrosting wait timer 16 are reset and the change-over switch 24 is changed over to AND circuit 21. Each of the timers 16, 17 and 20, operation circuit 18 and a restarting timer 21 is reset after the thermostat 15 is turned on again. On-signal of the defrosting thermostat 15 and Off-signal of a room temperature sensor 19 are checked by AND circuit 21 to perform a defrosting action. With this arrangement, it is possible to shorten the defrosting time.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a heat pump type air conditioner, and in particular to a defrosting method of an air conditioning method for defrosting an outdoor heat exchanger during heating operation. This invention relates to an operation control device.

(Prior Art) First, a general heat pump type air conditioning cellar will be explained with reference to FIG.

In FIG. 3, a compressor 1, a four-way valve 2, an indoor heat exchanger 3, a pressure reducing device 4, and a π external heat exchanger 5 are sequentially connected to form a refrigeration cycle.

A heat exchange sensor 7 and a room temperature sensor (
The detection output of the room thermostat) 8 is input to the control tllZ6, and indoor heating/cooling is controlled on and off according to the temperatures detected by both sensors 7 and 8.

The outdoor heat exchanger 5 is provided with a defrosting thermostat 9,
If moisture in the outside air freezes and forms frost on the outdoor heat exchanger 5 during heating operation, the refrigeration cycle is switched to heating operation, that is, the cycle in which the refrigerant flows from the indoor heat exchanger 3 to the outdoor heat exchanger 5, and vice versa. The refrigerant is switched to the cycle, and the a-temperature, high-pressure refrigerant is allowed to flow through the outdoor heat exchanger 5 for defrosting.

Conventionally, in this defrosting control, for example, after the temperature of the outdoor heat exchanger 5 becomes below a certain temperature, defrosting is started after a predetermined period of time has elapsed, and when the temperature becomes above a predetermined temperature, defrosting is ended, and I! A method of returning to full cell operation is often used.

However, the temperature at which defrosting of the outdoor heat exchanger 5 should start, the temperature at which defrosting should end, the defrosting operation time, etc. are experimentally determined values, and during actual use, the conditions at the time of the experiment ( In particular, when defrosting is completed, the defrosting time may become too long and the heating effect may be impaired if only the temperature of the outdoor heat exchanger is detected.

For this reason, a defrosting operation control device as shown in FIG. 4 has been proposed.

The defrosting operation control device in FIG. 4 includes a defrosting thermostat 9 that detects the temperature of the outdoor heat exchanger 5, a timer 10 for starting defrosting that is activated by the defrosting thermostat 9, and a timer 10 that is activated by the timer 10. Defrosting operation circuit 11, and
A timer 12 is provided which is operated by the timer 10 to regulate the defrosting operation time and returns from the defrosting operation to the heating operation when the timer expires.

The defrosting start and heating return operations by this device will be explained with reference to the flowchart in FIG. ), when it becomes less than the set value, the defrosting start timer 10 is operated, and after a predetermined time has elapsed by the start timer 10, the defrosting operation is performed (step 43.44). This defrosting operation (
Defrosting is performed in step 44), and the defrosting thermostat 9 detects the humidity of the outdoor heat exchanger 5 during defrosting.
Step 45: Determine whether the temperature is above a predetermined value.
), if it exceeds a predetermined value, a defrosting end signal is output (step 47), and heating operation is started (step 4) to indicate the end of defrosting.
Return to 1).

Further, if the temperature of the outdoor heat exchanger 5 is below a predetermined value, the heating return timer 12 activated by the defrosting thermostat 9 monitors the defrosting time (step 46), and when the predetermined time elapses, Even if the temperature of
) to return to heating operation (step 41).

In this control, the return from the defrosting operation to the heating operation is performed by either the defrosting thermostat 9 or the heating return timer 12, and even if the temperature of the outdoor heat exchanger 5 does not exceed a predetermined value, the return to the heating operation is performed. The timer 12 returns to heating operation, so that the defrosting time does not become too long and the heating effect is not impaired.

(Problems to be Solved by the Invention) The conventional device described above has the following problems. In other words, under actual usage conditions, defrosting may not be completely completed even if heating operation is returned to using the heating return timer, and in that case, lightning that could not be removed during defrosting may still be attached to the outdoor heat exchanger. As a result, this freezes again during heating operation. Therefore, each time the defrosting operation is repeatedly terminated by the heating return timer, the amount of ice on the outdoor heat exchanger increases, resulting in a decrease in heating capacity and user dissatisfaction.

The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a defrosting operation control device for an air conditioner with high heating efficiency that can reduce the number of defrosting operations and shorten the defrosting operation time. That is.

[Structure of the invention]

(Means for Solving the Problems) The present invention detects the state of the refrigeration cycle equipment of an air conditioner that controls the indoor temperature within a predetermined heating temperature range by on/off control of the @τ operation by the refrigeration cycle. Defrost start/end detection means that detects the start and end of defrosting of the exchanger and outputs a defrost start signal and a defrost end signal, and a defrost that outputs a defrost time-up signal after a set time has elapsed from the start of defrosting operation. and a timer means, the defrosting operation control device for an air conditioner is configured to terminate defrosting operation when at least one of the defrosting end signal and the defrosting time-up signal is input; Immediately after the heating operation ends, when the room temperature reaches a predetermined value and the heating operation ends, the refrigeration cycle is switched to the cooling operation on the condition that the defrosting start signal is output, and the outdoor heat exchange is performed. The present invention is characterized in that it is provided with a defrosting operation means for defrosting the container.

Furthermore, the present invention provides the defrosting operation control device according to the first aspect of the invention, such that the defrosting operation is not performed when the heating operation is turned off immediately after the defrosting operation by the defrosting operation means is canceled by the defrosting end signal. The device is characterized by being provided with a locking means for locking the device.

(Function) According to the present invention, the operation termination conditions of the previous defrosting operation are monitored, and when the defrosting start/end detection means is turned off, the defrosting operation is performed by the defrosting start/end detection means again this time, When the defrost timer times up, the current defrost operation can be performed according to the AND conditions of the defrost end signal and the room thermostat, making effective use of the restart time.
In the latter case, a good defrosting effect can be achieved while improving the heating operation rate.

(Embodiment) FIG. 1 shows an embodiment of a defrosting operation control device according to the present invention.

First, it is assumed that the configuration of the refrigeration cycle is the same as that shown in FIG. 3 already described.

FIG. 1 shows a block diagram of the defrosting operation control device of the present invention, in which a defrosting thermostat 15 is attached to the outdoor heat exchanger 5 (FIG. 3) as an example of defrosting start/end detection means. The on signal of this defrosting thermostat 15 is switched by a changeover switch 2 that is switched by a condition setting signal, which will be described later.
4 to the first input terminal of the defrost wait timer 16 or the AND circuit 21. When the changeover switch 24 is in the switching position on the defrosting timer 16 side, the defrosting timer 16 is set by the ON signal of the defrosting thermostat 15. The defrost operation circuit 18 is activated by the time-up signal of the defrost wait timer 16, and the defrost timer 17 is set. The defrosting operation circuit 18 and the defrosting timer 16 are reset by the time-up signal of the defrosting timer 17, and the condition setting changeover switch 24 is set to the AND circuit 2.
Switched to side 1. By turning off the defrosting thermostat 15, the defrosting timer 16, defrosting timer 17, and defrosting operation circuit 18 are reset, and the defrosting timer 20 and restart timer 21, which will be described later, are reset.

The AND circuit 21 checks the AND condition of the ON signal of the defrosting thermostat 15 and the OFF signal of the room thermostat 19 guided through the changeover switch 24, and when the condition is met, the defrosting operation circuit 18 starts the second defrosting operation. A frost timer 20 and a restart timer 21 are each set. The room thermostat 19 is provided as a means for detecting the temperature at the start and end of heating operation, is attached to the indoor heat exchanger 3, and is turned on when the room temperature falls below a predetermined value and exceeds a predetermined value higher than that. When it is, it turns off. The defrost operation circuit 18 is reset by the time-up signal of the defrost timer 20. The heating operation is started via the AND circuit 22 based on the time-up signal of the restart timer 21 and the ON signal of the room thermostat 19.

Defrosting operation is performed by switching the four-way valve 2 to the cooling operation side, turning off the outdoor fan and indoor fan (not shown), operating the compressor 1, and flowing high-temperature, high-pressure refrigerant to the outdoor heat exchanger 5. This is done by

The reason why the restart timer 21 is provided is that when the compressor 1 is once stopped, an excessive load is applied to the compressor 1 when restarted due to the pressure difference between the high pressure side and the low pressure side. This may result in a situation where smooth startup is not possible.
The goal is to prevent this. According to the above embodiment, since the four-way valve 2 is once switched, the pressure is balanced;
Excessive pressure will not be applied to the compressor 1 when restarting.

Next, the operation of the defrosting operation control device shown in FIG. 1 will be explained with reference to the flowchart shown in FIG.

During heating operation, the defrosting thermostat 15 turns off the outdoor heat exchanger 5.
The temperature is monitored (Step 101), and when the temperature falls below the defrosting start temperature, it is turned on and the defrost wait timer 16 is started (set) via the changeover switch 24 (Step 102).
. The defrosting timer 16 is used to prevent defrosting operation from starting due to a single malfunction of the defrosting thermostat 15, and is a timer that provides the time required for the inside of the refrigeration cycle to stabilize. Defrost thermostat 1~
If the detected temperature in step 15 does not fall below the defrosting start humidity,
The heating operation is continued (step 103). When performing the defrosting operation, following step 102, the presence or absence of the condition setting is determined by the switching position of the changeover switch 24 (step 104). This means that there is a condition setting in step 116, which will be described later, and corresponds to the state in which the selector switch 24 is switched to the AND circuit 21 side."No condition setting" means that there is a condition setting in step 116, which will be described later.
16, and corresponds to a state where the changeover switch 24 is switched to the defrost wait timer 16 side. In the latter case, that is, when no conditions are set, the defrosting operation is controlled according to the routine from step 112 to step 117, except that step 116 for setting conditions is newly provided. For example, the operation control operation is the same as that of the conventional device already described with reference to FIGS. 4 and 5. When this routine is entered, the defrost operation circuit 18 is activated when the defrost wait timer 16 times up (step 112), and defrost operation is started, and the defrost timer 17 is started (step 113). In this state, defrost thermostat 1
5 is monitored (step 114), and when it returns to the off state, a reset signal is sent to the defrost operation circuit 18 to cancel the defrost operation (step 117), and the defrost wait timer 16 and defrost Reset the frost timer 17. As long as the defrosting thermostat 15 continues to be on, the time counting operation of the defrosting timer 17 continues (steps 114 and 115), and when the time is up, the condition setting signal is turned on (step 116) to start the defrosting operation. Release (step 117).

The condition setting signal obtained in step 116 is used to switch the changeover switch 24 to the defrosting timer 16 side in order to execute the routine from step 105 to step 111 during the next de-N operation. Note that the defrost wait timer 1 is activated by the time-up signal of the defrost timer 17.
6 and its own reset operation is performed.

After the above defrosting operation, when the defrosting thermostat 101 turns on, the defrosting wait timer 16 starts as described above.
is set (steps 101 and 102), and the AND circuit 21 detects whether or not the condition setting signal is on, and whether or not the room thermostat 19 is off.Step 104
．． 105), the four-way valve 2 is activated by the output signal of the AND circuit 21 without waiting for the defrosting timer 16 to time up.
is reversed, the defrost timer 20 is set, the restart timer 21 is set, the compression mode is turned on, and the outdoor fan is stopped, and the defrost operation begins (step 106>. From then on, the defrost thermostat 15 and the defrost timer Steps 107 and 108) to monitor the operating status of the defrosting thermostat 1.
If 5 is turned off first, compression 1fi1 is turned off and the defrosting operation is canceled. However, the outdoor fan and the indoor fan are kept in a stopped state (step 109). In this state, the AND circuit 22 monitors whether or not the A N +) condition of the restart timer 21 time-up and the room thermostat 19 turning on is satisfied (step 110), and if the condition is met, the AND circuit 22 The heating operation begins (step 111). In step 107, even if the defrosting thermostat 15 is on (branch No.), when the defrosting timer 20 times up (step 108), the defrosting operation is canceled.

In this way, the present invention defrosts air by switching the four-way valve to flow high-temperature, high-pressure refrigerant into the outdoor heat exchanger when the air temperature rises above a set value during heating operation and heating operation is to be stopped. Do the following. Conventionally, compression is stopped when the air temperature rises or the room thermostat is turned off, and a restart timer (commonly referred to as a "3-minute timer") is set. Maximize the setting time,
Perform maximum defrost until the defrost thermostat returns to normal.

According to the above embodiment, the defrosting operation is not performed every time the room thermostat 19 is turned off, but the snow removal operation when the room thermostat is turned off is performed immediately after the defrosting operation is canceled by the defrosting timer 17. This is only when 19 is off. Therefore, the generation of refrigerant noise due to four-way valve switching can also be suppressed to a minimum.

In the above embodiment, the start and end of defrosting was detected based on the outdoor heat exchanger temperature, but instead, the state of the refrigeration cycle equipment, such as the compressor discharge side temperature and the input current of the compressor drive motor, was detected. You may do so.

(Effects of the Invention) As described above, according to the present invention, it is possible to realize effective defrosting by effectively using the time when the room thermostat is off, which does not require the heating operation. Efficiency improvements can be achieved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the defrosting operation control device for an air conditioner according to the present invention, FIG. 2 is a flowchart for explaining the operation of the device shown in FIG. 1, and FIG. System diagram showing the refrigeration cycle of the air conditioner to be applied, Part 4
The figure is a block diagram of a conventional defrosting operation control device, and FIG. 5 is a flowchart for explaining the operation of the device shown in FIG. 1... Compressor, 2... Four-way valve, 3... Indoor heat exchanger, 5... Outdoor heat exchanger, 15... Defrost thermostat, 17.20... Defrost timer, 18...Defrosting operation circuit, 19...Room thermostat, 21...
Condition setting changeover switch.

Claims (1)

[Claims] 1. Start defrosting of the outdoor heat exchanger by detecting the state of the refrigeration cycle equipment of the air conditioner that controls the indoor temperature within a predetermined heating temperature range by on/off control of the heating operation using the refrigeration cycle. Defrost start/end detection means detects the end and outputs a defrost start signal and a defrost end signal, and a defrost release timer means outputs a defrost time up signal after a set time elapses from the start of the defrost operation. , a defrosting operation control device for an air conditioner that terminates defrosting operation when at least one of the defrosting end signal and the defrosting time up signal is input,
When the room temperature reaches a predetermined value due to the heating operation immediately after the defrosting operation is terminated by the defrosting time-up signal and the heating operation is terminated, the refrigeration cycle is started on the condition that the defrosting start signal is output. A defrosting operation control device for an air conditioner, comprising a defrosting operation means for switching to cooling operation and defrosting the outdoor heat exchanger. 2. Detects the state of the refrigeration cycle equipment of the air conditioner, which controls the indoor temperature within a predetermined heating temperature range by on/off control of heating operation using the refrigeration cycle, and detects the start and end of defrosting of the outdoor heat exchanger. Defrost start/end detection means outputs a defrost start signal and defrost end signal, and defrost release timer means outputs a defrost time-up signal after a set time elapses from the start of defrosting operation, and the defrost end signal is detected. A defrosting operation control device for an air conditioner that terminates the defrosting operation when at least one of the defrosting time-up signal and the defrosting time-up signal is input,
When the room temperature reaches a predetermined value due to the heating operation immediately after the defrosting operation is terminated by the defrosting time-up signal and the heating operation is terminated, the refrigeration cycle is started on the condition that the defrosting start signal is output. a defrosting operation means that switches to cooling operation and performs defrosting operation on the outdoor heat exchanger;
An air conditioner characterized in that it is provided with a locking means for locking the defrosting operation from being performed when the heating operation is turned off immediately after the defrosting operation by the defrosting operation means is canceled by the defrosting end signal. Defrosting operation control device.