JPS6017639Y2 - Heat pump air conditioner - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a heat pump type air conditioner, and more particularly to a heat pump type air conditioner that is equipped with a four-way switching valve and can be heated or cooled by operating the switching valve.

Conventionally, in this type of air conditioner, when frosting occurs, a four-way selector valve is switched to circulate refrigerant in a reverse cycle to perform defrosting using high-humidity, high-pressure hot gas.

When a factory switches to defrost operation by operating a four-way selector valve, the evaporator is in a floft state, so the high pressure of hot gas passing through the evaporator is difficult to rise, resulting in a decrease in compressor input, and the defrost operation is reduced. There is a problem that the amount of heat required for defrosting is reduced and the defrost time becomes longer.

In addition, the switching operation of the four-way selector valve may cause liquid refrigerant to pack up from the condenser and damage the compression mechanism, or the differential pressure between high and low pressures may not reach a certain large value, causing lubricating oil to reach the lubricating part of the compression mechanism. There was a problem that the product was no longer supplied, resulting in a shortened lifespan.

However, the present invention was devised in view of the above problems, and it stops the flow of hot gas into the four-way switching valve during defrosting without switching the four-way switching valve, and controls the high pressure of the hot gas to the high-pressure control valve. to maintain a predetermined set pressure on the inlet side of the control valve, the high-pressure control valve is opened to allow hot gas to flow into the evaporator or the vicinity of the evaporator, and return to the compressor through the four-way selector valve. By shaping the cycle and increasing the work of the compressor during the cycle to a large amount commensurate with the set pressure of the high pressure, defrosting can be completed quickly and reliably using hot gas having a large amount of heat, and In addition to suppressing the liquid backflow that occurs when defrosting is performed by switching the conventional four-way switching valve,
This completely eliminates the problem of damage to the compression mechanism due to insufficient supply of lubricating oil.

That is, the present invention is a heat pump type air conditioner equipped with a four-way switching valve and capable of heating and cooling by operating the switching valve,
One end of the hot gas bypass pipe is connected to the discharge pipe between the discharge port of the compressor and the four-way switching valve, and the other end of the bypass pipe is connected to the discharge pipe between the heating expansion mechanism and the four-way switching valve. It is connected to the refrigerant passage that includes an outdoor coil that serves as a condenser during cooling and an evaporator during heating, and opens when the high pressure in the bypass pipe becomes higher than the high pressure during heating and cooling operation. A high pressure control valve is interposed, and an on-off valve is interposed in the discharge pipe between the connection part of the bypass pipe to the discharge pipe and the four-way switching valve, and when the outdoor coil frosts, the on-off valve It is characterized by the fact that it closes and defrosts the air.

The heat pump type air conditioner of the present invention will be described below based on embodiments and drawings.

In the drawings, A is an outdoor unit, B is an outdoor unit, and these units A and B are connected via a connecting pipe C9C.

The outdoor unit A includes a compressor 1, a four-way switching valve 2, an outdoor coil 3 that becomes a condenser during cooling and an evaporator during heating, an expansion mechanism 4 for heating such as a capillary tube, and the expansion mechanism 4.
A check valve 6 and a liquid receiver 7 are installed in the bypass pipe 5 that bypasses the
, an accumulator 8, and these devices are connected by a refrigerant pipe 9.

The indoor unit) B is an indoor coil 10 that serves as an evaporator during cooling and a condenser during heating, an expansion mechanism 11 for cooling such as a capillary tube, and a non-return check interposed in a bypass pipe 12 that bypasses the expansion mechanism 11. A valve 13 is provided, and these devices are connected by a refrigerant pipe 14.

The refrigerant pipes 9.14 of each of the units A and B are connected by the communication pipe C9C.

Further, 18 is an outdoor fan provided on the outdoor coil 3, and 19 is an indoor fan provided on the indoor coil 10.

Then, the four-way switching valve 2 is communicated as shown by the solid line to cause the refrigerant to flow in the direction of the solid line arrow to perform heating operation, and the four-way switching valve 2 is communicated as shown by the dotted line to allow the refrigerant to flow in the direction of the dotted line arrow. I am trying to run the air conditioner.

Therefore, in the heat pump type air conditioner configured as described above, the present invention provides a hot gas bypass pipe in the discharge pipe 9a between the discharge port of the compressor 1 and the four-way switching valve 2.
5 to connect the bypass pipe 15 to the refrigerant passage between the heating expansion mechanism 4 and the four-way switching valve 2 and including the outdoor coil 3. 15 is equipped with a high pressure control valve HPC that opens when the high pressure exceeds a predetermined value. An on-off valve 16 is provided so that when the outdoor coil 3 frosts, the on-off valve 16 is closed to perform defrosting.

That is, in the case shown in FIG. 1, the bypass pipe 15 connected to the discharge pipe 9a is connected to the refrigerant passage near the outlet of the outdoor coil 3 during heating, and the on-off valve 1
6, a command device 17 that issues a defrost command during defrosting;
During defrosting, the on-off valve 16 is closed in order to cause the high pressure control valve HPC to close by a command, and to set the high pressure value when the high pressure control valve HPC opens to a predetermined value higher than the high pressure value during air conditioning operation; The outdoor and indoor fans 18.19
is stopped and the hot gas discharged from the compressor is maintained near the outlet of the outdoor coil 3 by opening the control valve HPC while maintaining the predetermined high pressure value on the inflow side of the control valve HPC by the high pressure control valve HPC. is forced to flow out and return to the compressor 1 from the four-way selector valve 2 to form a defrost cycle, and the amount of work of the compressor 1 is made sufficient to match the predetermined high pressure, thereby eliminating the lack of heat. I forced myself to complete the defrost without any problems.

The on-off valve 16 uses a solenoid valve, and the command unit 17 is provided with, for example, a deicer (not shown), and the deicer detects frost and outputs an electric signal to issue a defrost command by energizing the coil of the solenoid valve. The opening/closing valve 16 is closed by the defrost command from the command unit 17.

However, in the above configuration, during heating operation, the high-temperature, high-pressure gas refrigerant shown at point A is discharged from the compressor 1 as shown in the Mollier diagram in Figure 2, condenses in the indoor coil 10, becomes liquefied, becomes a point state, and expands. It flows into the mechanism 4 and becomes the low temperature and low pressure state shown in point c.

Then, it is evaporated in the outdoor coil 3, becomes a low-pressure gas state at point 2, and flows into the compressor 1, thereby repeating the heating cycle I.

Then, a plot is generated in the outdoor coil 3, a defrost command is issued by the command unit 17, and the on-off valve 1
6 closes, the pressure of the discharged gas increases and the high pressure controller HPC
When the predetermined set pressure is reached and the state of point E in Figure 2 is reached,
The high-pressure controller HPC is opened, and the hot gas flows into the refrigerant flow path near the outlet of the outdoor coil 3 and becomes a high-temperature, low-pressure gas.

The heat held by the hot gas in this state is transferred to the outdoor coil 3.
The defrost cycle (3) is repeated where heat is conducted to the frost section of the compressor 1 to defrost the compressor 1, and the resulting low temperature and low pressure state is sucked into the compressor 1.

That is, during the defrost operation, the discharge pressure of the compressor 1 is maintained at the set pressure at point E, which is higher than the high pressure during the cooling/heating operation, so that the amount of work of the compressor 1 from point A to point A is matched to the set pressure. It is possible to make a large amount of hot gas, and the amount of heat held by the hot gas can be made sufficiently large, so that defrosting can be performed quickly without running out of heat, and the defrosting time can be shortened.

When the defrost is completed, the completion state is indicated by the command unit 1.
7 deicer detects and cancels the defrost command,
When the on-off valve 16 opens, the high pressure control valve HP
C is closed, and heating operation according to the heating cycle shown in FIG. 2 (3) is performed again.

In the above description, the hot gas bypass pipe 15 is
Although it is connected to the refrigerant passage near the outlet of the outdoor coil 3 during heating, it may also be connected in the middle of the outdoor coil 3, or between the outdoor coil 3 and the heating expansion mechanism 4 as shown by the dotted line in Figure 1. It may also be connected to the refrigerant path of
Defrosting can be performed more reliably.

In addition, since the predetermined value of the high pressure when the high pressure control valve HPC opens is set higher than the high pressure value during heating and cooling, it goes without saying that hot gas will not bypass to the low pressure side during heating and cooling. Even when the bypass pipe 15 is connected to the downstream side of the outdoor coil 3 during cooling as shown by the dotted line, bypassing to the connection position does not occur.

Furthermore, on the outlet side of the high pressure control valve HPC in the bypass pipe 15, there is a solenoid valve 2 that opens only during defrost, as shown by the dotted line in Figure 1.
0 may be provided, and it is possible to more reliably prevent hot gas from bypassing during cooling and heating.

As described above, the present invention connects the hot gas bypass pipe from the discharge pipe to the refrigerant passage between the heating expansion mechanism and the four-way switching valve, and also provides a high pressure in the bypass pipe that is higher than the high pressure during heating and cooling operation. a high-pressure control valve that opens when I tried to defrost it by
Since the pressure of the gas refrigerant discharged from the compressor during defrosting can be constantly maintained at a higher pressure than the high pressure set by the high pressure control valve during cooling/heating operation, the workload of the compressor can be adjusted to a level corresponding to the set pressure. The amount of heat held by the hot gas can be made sufficiently large, so defrosting can be performed quickly without running out of heat, and the defrosting time can be shortened.

Also, since the four-way selector valve is not switched at all during defrost, there is a problem caused by switching the four-way selector valve, as in the case of defrosting with a reverse cycle, that is, the liquid receptacle backs up from the outdoor coil that was performing the condensing action. Compared to the conventional method, damage to the compression mechanism can be suppressed, and the differential pressure between high and low pressures will not reach a certain large value, and lubricating oil will not be reliably supplied to the lubricating parts of the compression mechanism, which will shorten the service life. Furthermore, since refrigerant does not flow to the outdoor coil during defrosting, the indoor coil does not act as a cooling agent and reduce the heating effect, as is the case with reverse cycle defrosting. Not at all.

[Brief explanation of the drawing]

FIG. 1 is a refrigerant piping system diagram showing an embodiment of the present invention, and FIG. 2 is a Mollier diagram. 1... Compressor, 2... Four-way switching valve, 3
...Outdoor coil, 4...Heating expansion mechanism, 9a...Discharge pipe, 15...Bypass pipe, 16...Opening/closing valve , RPC...High pressure control valve.

Claims (1)

[Scope of utility model registration request] A heat pump type air conditioner equipped with a four-way switching valve 2 and capable of heating and cooling by operating the switching valve 2, in which a discharge pipe 9a between the discharge port of the compressor 1 and the four-way switching valve 2 ,
One end of the hot gas bypass pipe 15 is connected, and the other end of the bypass pipe 15 is connected to the refrigerant passage between the heating expansion mechanism 4 and the four-way switching valve 2, and serves as a condenser during cooling and evaporates during heating. A high pressure control valve HPC is connected to the refrigerant passage including the outdoor coil 3 serving as a container, and the bypass pipe 15 has a high pressure control valve HPC that opens when the high pressure becomes higher than the high pressure during air conditioning operation.
and further an on-off valve 16 is interposed in the discharge pipe 9a between the connection part of the bypass pipe 15 to the discharge pipe 9a and the four-way switching valve 2, and when the outdoor coil 3 is frosted, A heat pump type air conditioner characterized in that defrosting is performed by closing the on-off valve 16.