JPS6029562A - Defroster for air conditioner - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

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

Structure of the conventional example and its problems A conventional air conditioner, for example, as shown in Fig. 1, has a compressor (1), a four-way valve (2), an indoor heat exchanger (3), a pressure reducer (4), and an outdoor air conditioner. A υ refrigeration cycle is constructed by sequentially connecting the heat exchangers (5) with refrigerant piping and returning to the compressor (1) from the four-way valve (2) via the accumulator (6). As shown in Figure 1, the defrosting method in such a refrigeration cycle involves switching the four-way valve (2) from the heating mode of the refrigeration cycle to the cooling mode, and converting the frosted outdoor heat into an evaporator at low pressure during heating. Generally, defrosting is carried out by replacing the exchanger (5) with a condenser. However, in such a conventional defrosting system, the indoor heat exchanger (3) serves as an evaporator during defrosting operation, so if left as is, a cold draft will occur. Therefore, in order to prevent such cold drafts, an auxiliary heater Qυ is usually provided close to the indoor heat exchanger (3), and in order to suppress the refrigerant flowing into the indoor heat exchanger (3) as much as possible, ? J? 1 (3), (via pressure reducer (4)) l<
A bypass circuit 00 was provided, and control was performed to open the solenoid valve 00 in the bypass circuit 01. In addition, in this type of system, even if the indoor heat exchanger (3), which functioned as an evaporator during defrosting, returns to heating mode and returns to the condenser, the rise in pressure and temperature is slow due to its history. However, it had the disadvantage of lacking comfort because it took time to reach a steady state.

Purpose of the Invention The present invention has been made in view of the drawbacks of the conventional example, and
The purpose of this is to improve comfort by speeding up the start-up of heating capacity when the heating cycle is resumed after defrosting.

Structure of the Invention In order to achieve the above object, the present invention connects a compressor, a four-way valve, an indoor heat exchanger, a flow rate control valve, and an outdoor heat exchanger in sequence with refrigerant piping, and further provides the The indoor heat exchanger is connected to the compressor in return and constitutes a refrigeration cycle /I/ in which the four-way valve is opened in a first state, and the indoor heat exchanger is branched from between the flow rate control valve and the outdoor heat exchanger. A bypass circuit is provided for connecting the suction side of the compressor to the other end of the bypass circuit or the four-way valve via a three-way valve, and when the outdoor heat exchanger is frosted, the four-way valve is set to the second state, the discharge port of the compressor is guided to the outdoor heat exchanger, and the flow control valve is closed, and the three-way valve is switched to the bypass circuit side to direct the discharge port of the compressor to the outdoor heat exchanger. A control circuit is provided to cut off the valve side flow path opening.

With this configuration, high-temperature, high-pressure liquid refrigerant is confined within the indoor heat exchanger by the action of the flow control valve and three-way valve during defrosting operation.
This speeds up the start-up of heating capacity after defrosting.

Description of examples Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a refrigeration cycle according to an embodiment of the present invention, FIG. 8 is an electric circuit diagram thereof, and FIG. 4 is a diagram showing changes in heating capacity and a control method thereof.

In Figure 2, (1) is a compressor, (2) is a four-way valve, (
3) is an indoor heat exchanger, θ is an electric expansion valve, (5) is an outdoor heat exchanger, (A) is a three-way valve, and (6) is an accumulator, which are sequentially connected by refrigerant piping 08), A refrigeration cycle is constructed in which the four-way valve (2) is in the first state shown by the solid line and the refrigerant is passed in the above order. In addition, electric expansion valve α
A bypass circuit a including a pressure reducer (9) and a three-way valve (a) is connected from the outlet side of ``4'', and an accumulator (6
) is connected to the bypass circuit Q0 or the four-way valve (2) via the three-way valve.

In addition, the handle is an indoor heat exchanger.3) Nodame's temperature detector, (
7) and (8) are the blowers for the indoor heat exchanger (3) and the outdoor heat exchanger (5), respectively, and θ is the frost detector for the outdoor heat exchanger (5), and the electric expansion The valve θ has both a throttling action and the function of closing the pipe.

In Fig. 3, 04) is a power supply, to which the motor (1a) of the compressor (1) is connected in series via the operation switch θ0 and the start/stop switch (A) of the compressor (1). has been done. 0O is a control circuit that operates/stops the compressor (1) and defrosts the compressor (1) according to the numbers from the temperature detector (1) and the frost detector (11), and connects the power supply α4) via the switch 00. The connected switch αη switches between heating mode and defrosting mode. switch Q
Between the contact point (17a) of 7) and the other power line (c), there is an electromagnetic coil (2) that drives the four-way valve (2).
a), an electromagnetic coil (1) for driving the electric expansion valve Q2;
2a), the motor (7a) of the indoor heat exchanger blower (7)
), and the motor (8a) of the outdoor heat exchanger blower (8)
) is connected, and the other contact (17b
) and the line (c) are connected with an electromagnetic coil (22a) for driving the three-way valve.

In addition, when the three-way valve (a) is energized to the electromagnetic coil 1v (22a),
Connect to bypass circuit. In such a circuit configuration, by switching the switch 07), the contact (17a
) and (17b) are selectively connected to the power supply 04 via the operation switch (1).

Next, the operation of this embodiment will be described with reference to FIG. 4, focusing on the relationship between the temporal change in heating capacity, the defrosting cycle, and each valve control.

First, when the operation switch 00 is closed when the temperature of the air-conditioned room during heating is lower than the desired set temperature, the control device 0e receives a "low temperature" signal from the temperature detector 0e and closes the switch (c). At the same time, the switch 01 is brought into close contact with the contact (17a).

As a result, the compressor motor (1a), the indoor/outdoor heat exchanger fan motors (7a) and (8a), and the electromagnetic coils (2a) and (12&) are energized. This results in
The four-way valve (2) is in the heating mode shown by the solid line in Fig. 2, the electric expansion valve 02 is in the open state, and the compressor (1) is in the heating mode.
, the indoor heat exchanger blower (7), and the outdoor heat exchanger blower (8) are started. At this time, the three-way valve (a) connects the four-way valve (2) and the accumulator (6). As a result, the gas refrigerant compressed to high temperature and high pressure by the compressor (1) is condensed in the indoor heat exchanger (3) to become high temperature and high pressure liquid refrigerant, and is further depressurized by the electric expansion valve 0 to become low temperature and low pressure gas. It becomes a liquid two-phase refrigerant. This refrigerant flows into the outdoor heat exchanger (5), evaporates, passes through the four-way valve (2), the three-way valve (a), and the accumulator (6), and returns to the compressor Q). At this time, heat exchange is performed with the surrounding indoor air in the indoor heat exchanger (3), and warm air is blown toward the air-conditioned room by the indoor heat exchanger blower (7). That is, in FIG. 4, by closing the operation switch (10) and starting the heating mode at time 0,
The heating capacity increases over time, and the temperature of the air-conditioned room rises. After that, it is in a steady state for a certain period of time, but the outdoor heat exchanger (5)
The condensed moisture forms frost, which reduces the heat absorbing ability, so it is necessary to remove the frost.

Therefore, when the formed frost reaches a certain level, the frost detector 0υ detects the state and sends a signal to the control device Oe to switch it to the defrosting mode. In other words, the control device 06) operates the operating element of the switch θ to close the contact (17b) based on the signal from the frost detector (1]). As a result, motors (7a) and (8a),
Since the electromagnetic coils (2a) and (12&) are de-energized, the four-way valve (2) switches to the defrosting mode shown by the broken line in Fig. 2, and the electric expansion valve 0 becomes closed. , the indoor heat exchanger blower (7) and the outdoor heat exchanger blower (8) stop. At the same time, the three-way valve @O electromagnetic coil (22&) is energized, so the three-way valve (a) connects the bypass circuit 0 and the accumulator (6).

In this way, the high-temperature, high-pressure gas refrigerant discharged from the compressor (1) flows into the outdoor heat exchanger (5) and condenses, and due to the heat radiation effect in the process of becoming a high-temperature, high-pressure liquid refrigerant,
Melt the frost formed on the outdoor heat exchanger (5). The refrigerant flowing out from the outdoor heat exchanger (5) passes through the pressure reducer (9) and three-way valve (a) installed near the bypass circuit 0, returns to the compressor (1) from the accumulator (6), and returns to the compressor (1) from the accumulator (6). come. In this case, the electric expansion valve (i) and the three-way valve (c) confine the liquid refrigerant that was at high temperature and pressure during heating operation in the indoor heat exchanger (3).Then, after a certain period of time, it is removed. When the defrosting end signal is sent by the frost detector 01 which has recognized the frost condition, the control device (In is the switch Q
The operating element 71 is operated to close the contact (17a).

In this way, the four-way valve (2) switches to heating mode, and the three-way valve (a) returns to its original state because the electromagnetic coil (22 & ) that drives it to the second state is de-energized. The four-way valve (2) and the accumulator (6) are connected, and the electric expansion valve a is opened, and the blowers (7) and (8) are started, so that the heating operation is started again.

In this way, the present invention has an indoor heat exchanger (three
) during defrosting, the flow path opening is closed by the electric expansion valve 0 and the three-way valve, so the refrigerant state is maintained close to that during steady heating, that is, the inside of the container is maintained at high temperature and high pressure.
By sealing in the liquid refrigerant, when the defrosting mode is canceled and the heating mode is returned to, the amount of heat required to raise the indoor heat exchanger (3) to high temperature and high pressure is required. In addition, the retained liquid refrigerant immediately passes through the electric expansion valve a and flows into the outdoor heat exchanger to exert an endothermic effect, so that the heating capacity can be increased quickly.

In addition, some percentage of the total amount of refrigerant charged in the refrigeration cycle is trapped in the indoor heat exchanger (3) by two valves during defrosting operation, so the compressor Liquid compression can be prevented. This is because in the past, liquid refrigerant that could not be evaporated during defrosting would accumulate in the accumulator (6), overflow and be sucked into the compressor (1), causing liquid compression. It is thought that such a problem will not occur due to the control method as described above.

In this example, the main circuit was closed during the defrosting operation by using an electric expansion valve with both a throttling action and a circuit-closing function. Even when used in combination with a solenoid valve, the same function as the electric expansion valve described above can be achieved.In addition, the pressure reducer in the bypass circuit is especially suitable if it can be used in common with the pressure reducer in the main circuit. There's no need.

Further, in this embodiment, switching of the four-way valve (2) and control of other valves are synchronized, but these controls may have a certain degree of time difference. However, it is more effective to close the flow control valve 0 at the same time as switching the four-way valve (2), or a little earlier, and switch the three-way valve (A).

As described in detail, the present invention switches the four-way valve during defrosting operation to guide the compressed gas refrigerant to the outdoor heat exchanger, while at the same time maintaining the refrigerant state close to the steady state of heating in the indoor heat exchanger. By doing so, the heating capacity can be started up quickly after defrosting, and comfort can be improved. However, it still exhibits excellent effects such as being able to prevent liquid compression.

[Brief explanation of the drawing]

Fig. 1 is a refrigeration cycle configuration diagram showing a conventional example, Fig. 2 is a refrigeration cycle configuration diagram showing an embodiment of the present invention, Fig. 3 is an electric circuit diagram in an embodiment of the present invention, and Fig. 4 is a heating cycle diagram. It is a graph showing a change in capacity over time and each valve control. (1)・・・・・・・・・・・・Compressor (2)・
・・・・・・・・・・・・・・・Four-way valve (3)・・・・・・
・・・・・・・・・Indoor heat exchanger (5)・・・・・・
......Outdoor heat exchanger 0...
・・・・・・Flow rate control valve 0e・・・・・・・・・・・・
...Control circuit 0... Bypass circuit (a) ... Three-way valve patent applicant Matsushita Electric Industrial Co., Ltd. Agent Shinji Kenbu (1 other person) Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] A compressor, a four-way valve, an indoor heat exchanger, a flow rate control valve, and an outdoor heat exchanger are sequentially connected by refrigerant piping, and further connected back to the compressor via the four-way valve, and the four-way valve is brought into a first state. A refrigeration cycle opened to traffic is configured, and a bypass circuit for the indoor heat exchanger is provided that branches from between the flow rate control valve and the outdoor heat exchanger, and the suction side of the compressor is connected to the suction side of the compressor through a three-way valve. and connect the bypass circuit to the other end of the bypass circuit or the four-way valve, and when the outdoor heat exchanger is frosted, the four-way valve is set to a second state to guide the discharge port of the compressor to the outdoor heat exchanger. , and before ffp
A defrosting device for an air conditioner, comprising a control circuit that closes a quantity control valve and further switches the three-way valve to a bypass circuit side to cut off a four-way valve side flow path opening of the indoor heat exchanger.