JPS618543A - Apparatus for controlling defrosting operation in refrigerating cycle in air conditioner - Google Patents

Abstract

PURPOSE:To reduce a generation of noise or vibration when a unit is changed over from a defrosting operation to a heating operation by a method wherein a first time measuring means for measuring a time elapsed by turning off a circuit of compressor and closing a four-way valve circuit in an indoor unit after a predetermined time is elapsed and a second time measuring means for similarly closing the circuit of compressor in the indoor unit after a predetermined time is elapsed are arranged. CONSTITUTION:When a sensing means 6 detects a releasing of condition of frosting during a defrosting operation, a four-way valve circuit contact point 8 is closed and then a four-way valve 5 is energized. A current sensor 7 may detect an energization to open the contact points 11 and 13 with a slight time delay of DELTAt after energization, the four-way valve 5 is set to a refrigerating cycle and then a compressor 1 is terminated to operate. At the same time, the contact points 17 and 18 are closed and the timer 15 measures a desired time t1, resulting in that the contact point 12 is closed to energize the four-way valve 5 and change-over the operation to a heating cycle. Subsequently, when the timer 16 measures a desired time t2, the contact point 14 is closed to operate the compressor 1 and then a heating operation is started. Since the delay in time DELTAt is sufficiently low as compared with an operating time of the four-way valve 5, a differential pressure across the four-way valve 5 is eliminated during the desired time t1 and then the noise and vibration when the four-way valve 5 is changed over are decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a defrosting operation control device for a refrigeration cycle of an air conditioner.

Configuration of conventional example and its problems The refrigeration cycle of a conventional general air conditioner consists of a compressor 1. Indoor heat exchanger 2° throttling device 3. Outdoor heat exchanger4. When the four-way valves 5 are connected in an annular manner and the four-way valve 6 is energized, the refrigerant discharged from the compressor 1 is sequentially transferred to the four-way valve 6, the indoor heat exchanger 2. Squeezing device 3
．． Outdoor heat exchanger4. The refrigerant passes through the four-way valve 6 and is drawn into the compressor 1, forming a heating operation cycle. Four-way valve6. Outdoor heat exchanger4. Squeezing device 3. Indoor heat exchanger 2. Four-way valve6. The air flows in the order of compressor 1, forming a cooling operation cycle. When performing heating operation with this type of air conditioner, if the evaporation temperature in the outdoor heat exchanger drops sufficiently due to conditions such as outdoor temperature,
Frost grows on the outdoor heat exchanger 4, interfering with heat exchange and significantly reducing heating capacity. Therefore, by using means for detecting sheathing conditions such as the temperature of the outdoor heat exchanger 4, frost formation on the outdoor heat exchanger 4 is automatically detected, and the power supply to the four-way valve 5 is cut off. The cooling cycle is constructed by flowing a high-pressure, high-temperature refrigerant through the outdoor heat exchanger 4 to melt the frost, and when the frosting condition detection means detects the melting of the frost, the four-way valve 6 is energized again to resume heating operation. It had a defrosting operation control such as returning. Further, during the defrosting operation, it is necessary to stop the indoor fan in order to cool the indoor heat exchanger 2, and therefore, a means for determining whether or not defrosting is being performed is required in the indoor unit. For this reason, for example, as shown in FIG. 5, a current detector 7 is provided in the electric circuit of the four-way valve 5 to detect the opening and closing of the four-way valve circuit. FIG. 4 is a circuit diagram of such a conventional example. When the frosting condition detecting means 6 installed in the outdoor unit A opens the contact 8 on the electric circuit of the four-way valve 5, defrosting operation starts, and at the same time the indoor A current detector 7 placed in the electric circuit of the four-way valve 6 in the machine B detects the non-energization and stops the indoor blower (not shown). Further, when the frosting condition detection means 6 determines that defrosting is not necessary, the contact 8 on the electric circuit of the four-way valve 5 is closed, and at the same time, the current detector 7 detects energization and the indoor blower (not shown) resumes operation. do.

Note that 1o is a power source.

By the way, in this type of refrigeration cycle, it has been known that when switching from defrosting operation to heating operation, large noise and vibrations are generated due to the backflow of refrigerant when the four-way valve is switched. In addition, in order to solve this problem, it is recommended to temporarily stop the operation of the compressor before energizing the four-way valve, and then energize the four-way valve once the pressure difference across the four-way valve has been sufficiently eliminated. It is being However, as is clear from the circuit configuration above, indoor unit B, where most of the electronic circuits are normally housed,
In this case, it is impossible to detect the frosting condition and cut off the circuit of the compressor 1 before the operation of the four-way valve 5 because the indoor unit detects the defrosting operation by the operation of the four-way valve. Furthermore, if a circuit for controlling the operation of the compressor 1 is provided in the outdoor unit A, such control becomes possible, but this not only results in a significant increase in cost and an increase in the complexity and size of the structure, but also in the case of outdoor equipment with severe environmental conditions. Placing an electric circuit inside machine A is undesirable in terms of safety and lifespan, so this method has the disadvantage of being difficult to adopt.

OBJECT OF THE INVENTION The present invention solves the above-mentioned conventional drawbacks, and aims to reduce noise and vibration during the transition from defrosting operation to heating operation without installing a new electric circuit inside the outdoor unit. .

Composition of the invention To achieve this blindness, a compressor and a four-way valve are used.

An indoor heat exchanger, a throttle device, and an outdoor heat exchanger are connected in a ring to form a refrigeration cycle for both cooling and heating, and it is possible to detect whether or not frost has formed on the outdoor heat exchanger inside the outdoor unit. The indoor unit is equipped with a frost condition detection means that opens and closes the four-way valve circuit, and a current detector that detects the opening and closing of the four-way valve circuit is installed in the indoor unit. A means for cutting off the valve circuit, a means for cutting off the compressor circuit in the indoor unit with the same signal, and a means for cutting off the compressor circuit and signing.
a first timer that measures the time since then and closes the four-way valve circuit within the indoor unit when a preset time has elapsed, and a second timer that closes the compressor circuit within the indoor unit when the preset time has also elapsed. It is composed of means.

With this configuration, noise at the time of switching from defrosting operation to heating operation can be reduced.

DESCRIPTION OF EMBODIMENTS The present invention will be described below with reference to FIGS. 1 and 2 showing one embodiment thereof.

The refrigeration cycle of the air conditioner of the present invention is similar to the conventional one shown in FIG. 4, and FIG. 1 shows its control circuit.

In FIG. 1, 1 is a compressor, 6 is a four-way valve, 6 is a sheathed condition detection means, 8 is a four-way valve circuit contact that is activated by the detection signal of the sheathed condition detection means 6, 7 is a current detector, 11. 1
3, 17, and 18 are contacts activated by the detection signal of the current detector 7; 15, 16 are timers each equipped with contacts 12 and 14; 10 is a power source; and the compressor 1. Four-way valve6. Frosting condition detection means 6. The four-way valve circuit contact 8 is incorporated into the outdoor unit A, and the current detector 7. Timer 15, 16. Contact 11゜12
．． 13, 14, 17, and 18 are built into indoor unit B.

Then, the timers 15 and 16 are connected to the power supply 10 at contact 1, respectively.
7.18, the compressor 1 is connected to the power supply 10 through the contact 13, the four-way valve 5 and the current detector 7 are connected in series to the power supply 1° through the contacts 8 and 11, and the A contact 12 is connected in parallel with 11, and a contact 14 is connected in parallel with contact 13. Therefore, the timer 16 is a first timing means that closes the circuit of the four-way valve 6 after a predetermined set time t1 after the circuit of the compressor 1 is cut off.
6 is a predetermined set time t2 after the circuit of the compressor 1 is cut off.
It becomes a second timer that later closes the circuit of the compressor 1.

Here, when the frosting condition detection means 6 determines that the frosting condition has been canceled during the defrosting operation, the four-way valve circuit contact 8 closes and the four-way valve 5 is energized. When the four-way valve 6 is energized, the current detector 7 detects the energization of the four-way valve 6, and after a slight time delay Δt after the four-way valve 5 is energized, contacts 11 and 13 are opened.
The four-way valve 5 enters the cooling cycle, and the compressor 1 stops.

At the same time, the contacts 17 and 18 close and the timers 15 and 16 start measuring time. When the timer 16 measures the set time t1, the contact 12 is closed and the four-way valve 5 is energized to switch to the heating cycle, and then the timer 16 starts counting the set time t2. Contact 1 when timing
4 is closed, the compressor 1 is driven, and heating operation begins.

A timing chart of the operations of the compressor 1 and the four-way valve 5 described above is as shown in FIG. Here, since the above-mentioned time delay △t is sufficiently smaller than the operating time of the four-way valve 5, the time delay △
During time t, even if the four-way valve is temporarily energized, the four-way valve does not operate, and the cooling cycle for defrosting operation is started by timer 15.
is held until the set time t1 is counted. During this time, the pressure difference before and after the four-way valve 5 is sufficiently eliminated, and the noise and vibrations caused when the four-way valve 6 is switched after the set time t1 has elapsed are suppressed to a sufficiently low level.

Effects of the Invention As is clear from the above embodiments, the defrosting operation control device for the refrigeration cycle of an air conditioner according to the present invention allows the operating time of the four-way valve to match the indoor unit without providing a new electric circuit to the outdoor unit. The compressor can be stopped before the four-way valve switches cycles by taking advantage of the fact that the current detector detects the current and stops energizing the four-way valve, which is sufficiently long compared to the time it takes to stop energizing the four-way valve. As a result, by simply adding a partial determination function to the indoor unit, it is possible to significantly reduce the large noise and vibrations at the end of defrosting, which have been a problem in the past.

[Brief Description of the Drawings] Fig. 1 is a circuit diagram of a defrosting operation control device for a refrigeration cycle of an air conditioner showing one embodiment of the present invention, Fig. 2 is an operation timing chart of the device, and Fig. 3 is a A refrigeration cycle diagram of an air conditioner, FIG. 4 is a circuit diagram of a conventional defrosting operation control device. 1... Compressor, 2... Indoor heat exchanger, 3...
... Throttle device, 4... Outdoor heat exchanger, 6.
・・Four-way valve, 6・−・Frost condition detection means, 7・・・・
Current detector, 8...Four-way valve circuit contact, 11...
・Contact (means to cut off the four-way valve circuit), 12... Contact (means to cut off the compressor circuit), 16... Timer (first time measurement means), 16... Timer (second timekeeping means), A...outdoor unit, B...indoor unit. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3

Claims (1)

[Claims] The compressor, four-way valve, indoor heat exchanger, throttling device, and outdoor heat exchanger are connected in a ring to form a refrigeration cycle for both cooling and heating, and the outdoor heat exchanger is frosted inside the outdoor unit. A frosting condition detection means is provided to detect whether or not the four-way valve circuit is open or closed, a current detector is provided in the indoor unit to detect the opening or closing of the four-way valve circuit, and upon receiving a signal from the current detector, A means for immediately interrupting the four-way valve circuit within the indoor unit, a means for interrupting the compressor circuit within the indoor unit using the same signal, and a means for measuring the time elapsed after the compressor circuit is interrupted and preset. Refrigeration of an air conditioner, comprising a first timer that closes the four-way valve circuit within the indoor unit when a preset time has elapsed, and a second timer that closes the compressor circuit within the indoor unit when a preset time has elapsed. Cycle defrosting operation control device.