KR101203581B1 - Heat pump - Google Patents

Abstract

The heat pump according to the present invention is configured such that at least some of the refrigerant condensed in the indoor heat exchanger during the heating operation is bypassed to the accumulator, whereby the bypassed refrigerant raises the refrigerant temperature in the accumulator by heat exchange, thereby Intake temperature and evaporation pressure of the is increased, there is an effect that can prevent frost from forming on the surface of the outdoor heat exchanger.

Description

Heat Pump {HEAT PUMP}

The present invention relates to a heat pump, and more particularly, to a heat pump that can prevent the phenomenon of frost on the outdoor heat exchanger during the heating operation.

In general, an air conditioner is a device for cooling or heating an indoor space by performing a process of compressing, condensing, expanding, and evaporating a refrigerant. The air conditioner is classified into a general air conditioner in which one indoor unit is connected to an outdoor unit, and a multi air conditioner in which a plurality of indoor units are connected to the outdoor unit. The air conditioner includes a compressor, a condenser, an expansion valve, and an evaporator. The refrigerant discharged from the compressor is condensed in the condenser and then expanded in the expansion valve. The expanded refrigerant is evaporated in the evaporator and then sucked into the compressor.

In the case of a heat pump capable of both cooling operation and heating operation, the outdoor heat exchanger acts as a condenser to condense the high temperature and high pressure refrigerant discharged from the compressor during the cooling operation with the outdoor heat exchanger and condense it into liquid refrigerant. The heat exchanger acts as an evaporator. On the other hand, during the heating operation of the air conditioner, the outdoor heat exchanger serves as an evaporator for heat-exchanging the refrigerant in a mixed state of the gas and liquid recovered from the indoor heat exchanger with the outdoor heat exchanger and evaporating the refrigerant in the gas state. It acts as a condenser.

However, when the temperature of the outdoor air is below a certain temperature or the humidity is high, condensation occurs on the surface of the outdoor heat exchanger to form water droplets, and freezing occurs at a temperature below zero. When freezing occurs in the outdoor heat exchanger as described above, since the heat exchange between the outdoor air and the refrigerant is prevented, there is a problem of lowering the heating performance.

An object of the present invention is to provide a heat pump capable of raising the refrigerant temperature in the accumulator during heating operation to increase the suction temperature and evaporation pressure of the compression, and to prevent frost on the outdoor heat exchanger.

The heat pump according to the present invention for solving the above problems, a compressor for compressing the refrigerant, an indoor heat exchanger for condensing the refrigerant compressed by the compressor during the heating operation, an expansion device for expanding the refrigerant from the indoor heat exchanger And an outdoor heat exchanger for evaporating the refrigerant from the expansion device during the heating operation, an accumulator for separating gaseous refrigerant from the refrigerant from the outdoor heat exchanger and sending it to the compressor, and a low temperature refrigerant from the indoor heat exchanger during the heating operation. A bypass flow path for bypassing heat exchange while at least a portion passes through the accumulator, and a difference between a temperature of the refrigerant passing through the accumulator and a temperature of the refrigerant from the indoor heat exchanger during heating operation maintains a preset value. Flow rate of refrigerant bypassed to the bypass flow path It includes a heat pump including a control unit for controlling.

In an embodiment of the present invention, further comprising a refrigerant passage connecting the indoor heat exchanger and the outdoor heat exchanger, wherein the bypass passage is branched from the refrigerant passage, passes through the accumulator, and is then connected to the refrigerant passage again.

In the present invention, it may further include a flow rate control valve for heating disposed in the coolant flow path for controlling the flow rate of the refrigerant to be bypassed to the bypass flow path during the heating operation.

In the present invention, the cooling flow rate control valve disposed in the bypass flow path for controlling the flow rate of the refrigerant bypassed to the bypass flow path from the refrigerant condensed in the outdoor heat exchanger during the cooling operation may further include. have.

In the present invention, it further comprises a bypass flow path temperature sensor disposed in the bypass flow path for measuring the temperature of the refrigerant passing through the accumulator during the heating operation.

In the present invention, it further comprises a refrigerant flow path temperature sensor disposed in the refrigerant flow path, for measuring the temperature of the refrigerant from the indoor heat exchanger during the heating operation.

In the present invention, the control unit for controlling the opening degree of the heating control valve so that the temperature difference sensed by the bypass flow path temperature sensor and the refrigerant flow path temperature sensor maintains a preset value.

In the present invention, the bypass passage includes a refrigerant pipe inserted into the lower portion of the accumulator.

The heat pump according to the present invention is configured such that at least some of the refrigerant condensed in the indoor heat exchanger during the heating operation is bypassed to the accumulator, whereby the bypassed refrigerant raises the refrigerant temperature in the accumulator by heat exchange, thereby Intake temperature and evaporation pressure of the is increased, there is an effect that can prevent frost from forming on the surface of the outdoor heat exchanger.

In addition, there is an advantage that the heating performance can be improved by increasing the discharge temperature of the compressor.

In addition, the heat pump according to the present invention bypasses the refrigerant condensed in the outdoor heat exchanger to the accumulator during the cooling operation, so that the bypass flow path and the accumulator serve as the supercooler, so that a separate subcooling heat exchanger is required. There is an advantage of not being.

1 is a view showing the refrigerant flow inside the outdoor unit when the heat pump is a heating operation according to an embodiment of the present invention.
2 is a view showing a refrigerant flow inside the outdoor unit when the heat pump according to an embodiment of the present invention is a heating operation and the outdoor temperature is less than the set temperature.
3 is a view showing the refrigerant flow inside the outdoor unit when the heat pump is a cooling operation according to an embodiment of the present invention.
4 is a view schematically showing an accumulator according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

1 is a view showing the refrigerant flow inside the outdoor unit when the heat pump is a heating operation according to an embodiment of the present invention. 2 is a view showing a refrigerant flow inside the outdoor unit when the heat pump according to an embodiment of the present invention is a heating operation and the outdoor temperature is less than the set temperature. 3 is a view showing the refrigerant flow inside the outdoor unit when the heat pump is a cooling operation according to an embodiment of the present invention. 4 is a view schematically showing an accumulator according to an embodiment of the present invention.

1 to 3, the heat pump according to the present invention is a compressor 10 for compressing a refrigerant in a state of high temperature and high pressure, and is installed in the room to act as an evaporator during the cooling operation and a condenser during the heating operation A heat exchanger (not shown), an outdoor heat exchanger 20 installed outdoors to serve as a condenser in a cooling operation and an evaporator in a heating operation, an expansion device for expanding a refrigerant passing through the condenser, and the compressor ( 10 includes a four-way valve 30 for switching the flow path such that the refrigerant flowing from the indoor heat exchanger (not shown) or the outdoor heat exchanger 20 according to the cooling and heating operation.

In addition, the heat pump further includes an accumulator 40 for allowing only the gas refrigerant of the refrigerant evaporated from the evaporator to flow into the compressor 10.

The compressor 10 may include a plurality of compressors, which will be described as including a variable compressor 11 and a constant speed compressor 12 in this embodiment.

A hot gas flow passage 13 is connected to the discharge side of the compressor 10 to allow the refrigerant passing through the compressor 10 to flow into the suction side of the compressor 10, that is, the accumulator 40. The gas flow passage 13 may be provided with a hot gas valve 14 for controlling the amount of refrigerant.

An inlet 41 through which the refrigerant evaporated in the evaporator and the refrigerant in the hot gas flow passage 13 is formed at one upper side of the accumulator 40. On the other side of the upper part of the accumulator 40, a discharge port 42 for discharging the refrigerant in the gas state to the compressor 10 is formed. The discharge port 42 is connected to the suction side of the compressor 10.

The indoor heat exchanger (not shown) and the outdoor heat exchanger 20 are connected by a refrigerant passage 22.

The heat pump further includes a bypass flow path 50 for bypassing at least a portion of the low temperature refrigerant from the indoor heat exchanger (not shown) to the accumulator 40 side during the heating operation.

The bypass flow path 50 branches off from the coolant flow path 22 and passes through the accumulator 40, and then is connected to the coolant flow path 22 again. That is, the bypass passage 50 is connected to the first passage 50a branched from the refrigerant passage 22 and the second passage 50b connected to the first passage 50a and disposed in the accumulator 40. ) And a third passage 50b connected to the second passage 50b and connected to the refrigerant passage 22.

Referring to FIG. 3, the second flow path 50b is a refrigerant pipe inserted into the accumulator 40, and the refrigerant pipe is wound in a spiral shape to secure a heat exchange area. Since the accumulator 40 has a liquid refrigerant sinking in the lower portion, the second flow path 50b is preferably disposed under the accumulator 40.

The refrigerant flow passage 22 is provided with a heating flow control valve 24 for controlling the flow rate of the refrigerant bypassed to the bypass flow passage during the heating operation.

In the bypass flow path 50, a cooling flow control valve 52 for controlling the flow rate of the refrigerant bypassed to the bypass flow path 50 among the refrigerant condensed in the outdoor heat exchanger 20 during the cooling operation. Is installed.

The cooling flow rate control valve 52 may be installed at the inlet side during the cooling operation of the accumulator 40 on the bypass flow path 50.

The bypass passage 50 is provided with a bypass passage temperature sensor 54 for measuring the temperature of the refrigerant passing through the bypass passage 50.

The bypass flow path temperature sensor 54 is installed at the outlet side of the accumulator 40 to measure the temperature of the refrigerant passing through the accumulator 40 during the heating operation.

The refrigerant passage 22 is provided with a refrigerant passage temperature sensor 26 that measures the temperature of the refrigerant from the indoor heat exchanger (not shown) during heating operation. The coolant flow path temperature sensor 26 may be installed before a point where the bypass flow path 50 branches on the coolant flow path 22.

The outdoor heat exchanger 20 may be provided with a condensation temperature sensor 28 for detecting the condensation temperature of the refrigerant condensed in the outdoor heat exchanger 20 during the cooling operation.

The heat pump further includes a control unit (not shown) for controlling the heating flow control valve 24 and the cooling flow control valve 52.

The control unit (not shown) is an opening degree of the heating control valve 24 so that the temperature difference detected by the bypass flow path temperature sensor 54 and the refrigerant flow path temperature sensor 26 maintains a preset value during heating operation. To control. When the difference between the temperature sensed by the bypass channel temperature sensor 54 and the temperature sensed by the refrigerant channel temperature sensor 26 is less than a set value, the opening degree of the heating control valve 24 is reduced to reduce the bypass flow path ( 50) may increase the flow rate of the refrigerant bypassed.

In addition, the controller (not shown) is a temperature difference value detected by the condensation temperature sensor 28 and the refrigerant flow path temperature sensor 26, that is, the supercooling degree, in a cooling operation, within a preset range. The opening degree of the cooling flow control valve 54 may be controlled to lift. When the subcooling degree is less than a set value, the degree of subcooling may be increased by increasing the flow rate of the refrigerant cooled in the accumulator 40 by increasing the opening degree of the cooling flow rate control valve 54. At this time, the heating flow control valve 24 may be fully opened.

Looking at the operation of the heat pump according to an embodiment of the present invention configured as described above are as follows.

First, referring to FIG. 1, during the heating operation, the compressed high temperature and high pressure refrigerant is introduced into the indoor heat exchanger (not shown) through the four-way valve 30.

The refrigerant condensed in the indoor heat exchanger (not shown) is introduced into the outdoor unit through the refrigerant passage 22. The refrigerant introduced into the outdoor unit is evaporated in the outdoor heat exchanger 20 and then enters the suction side of the compressor 10 via the accumulator 40.

Referring to FIG. 2, in the heating operation, when the outdoor temperature is less than or equal to the set temperature or the temperature sensed by the outdoor heat exchanger temperature sensor 29 is less than or equal to the preset temperature, frost is prevented from forming in the outdoor heat exchanger 20. To this end, the control unit (not shown) controls the opening degree of the heating flow control valve 24.

 By controlling the opening degree of the heating flow control valve 24, it is possible to control some of the refrigerant from the indoor heat exchanger (not shown) to pass through the accumulator 40 through the bypass flow path 50. have.

In addition, the controller (not shown) controls the opening degree of the heating control valve 24 so that the temperature difference detected by the bypass flow path temperature sensor 54 and the refrigerant flow path temperature sensor 26 maintains a preset value. do. When the difference between the temperature sensed by the bypass channel temperature sensor 54 and the temperature sensed by the refrigerant channel temperature sensor 26 is less than a set value, the opening degree of the heating control valve 24 is reduced to reduce the bypass flow path ( 50) may increase the flow rate of the refrigerant bypassed.

The refrigerant bypassed to the bypass passage 50 exchanges heat with the accumulator 40 while passing through the accumulator 40. In general, the refrigerant temperature inside the accumulator 40 is much lower than the temperature of the refrigerant condensed in the indoor heat exchanger (not shown) and bypassed to the bypass flow path 50. Accordingly, the bypassed coolant is cooled by losing heat to the coolant inside the accumulator 40. The refrigerant inside the accumulator 40 absorbs heat from the bypassed refrigerant, and the refrigerant temperature inside the accumulator 40 is increased.

When the refrigerant temperature inside the accumulator 40 rises, the suction temperature and the discharge temperature of the compressor 10 increase, and the evaporation pressure rises, causing frost to form on the surface of the outdoor heat exchanger 20. Can be prevented.

Increasing the discharge temperature of the compressor 10 may also improve the indoor heating supply capability.

 When the opening degree of the heating flow control valve 24 is reduced, the flow rate of the refrigerant bypassed to the bypass flow path 50 may be increased. When the opening degree of the heating flow control valve 24 is increased, the flow rate of the refrigerant bypassed to the bypass flow path 50 may be reduced. That is, the bypass flow rate is controlled by the heating flow control valve 24, and as described above, the temperature difference detected by the bypass flow path temperature sensor 54 and the refrigerant flow path temperature sensor 26 is a preset value. The opening degree of the control valve 24 for heating is controlled to maintain.

In addition, the control unit (not shown) may control the degree of opening of the flow control valve 24 for heating, to perform the superheat degree control.

In the present embodiment, when the outdoor temperature is lower than the set temperature, such as frost on the surface of the outdoor heat exchanger 20, the opening degree of the heating flow control valve 24 is limited. As described above, the heating flow control valve 24 may also be controlled to control the superheat degree or to raise the suction side temperature of the compressor 10.

Referring to FIG. 3, the refrigerant compressed by the compressor 10 during the cooling operation is introduced into the outdoor heat exchanger 20 through the four-way valve 30. The refrigerant condensed in the outdoor heat exchanger 20 flows into the indoor heat exchanger (not shown) along the refrigerant passage 22. The refrigerant evaporated in the indoor heat exchanger (not shown) enters the suction side of the compressor 10 via the accumulator 40.

During the cooling operation, the controller (not shown) controls the opening degree of the cooling flow control valve 54 to accumulate some of the refrigerant from the outdoor heat exchanger 20 through the bypass flow path 50. (40) can be bypassed.

The refrigerant bypassed to the bypass flow path 50 exchanges heat in the accumulator 40. Since the refrigerant temperature inside the accumulator 40 is lower than the temperature of the bypassed refrigerant, the bypassed refrigerant is further lowered while passing through the accumulator 40. That is, the bypass flow path 50 and the accumulator 40 may function as a supercooler during the cooling operation.

The controller (not shown) controls the cooling flow rate such that the condensation temperature detected by the condensation temperature sensor 28 and the temperature difference value detected by the refrigerant flow path temperature sensor 26, that is, the supercooling, fall within a preset setting range. The degree of opening of the valve 54 can be controlled. When the subcooling degree is less than a set value, the degree of subcooling may be increased by increasing the flow rate of the refrigerant cooled in the accumulator 40 by increasing the opening degree of the cooling flow rate control valve 54. At this time, the heating flow control valve 24 may be fully opened.

Therefore, the cooling unit may serve as a supercooler by the bypass passage 50 and the accumulator 40 even when a separate supercooler is not installed during the cooling operation. The temperature inside the accumulator 40 may be raised to increase the suction temperature of the compressor 10.

10: compressor 20: outdoor heat exchanger
22: refrigerant flow path 24: flow control valve for heating
30: 4-way valve 40: accumulator
50: bypass flow path 54: cooling flow control valve

Claims (8)

A compressor for compressing the refrigerant;
An indoor heat exchanger configured to condense the refrigerant compressed by the compressor during a heating operation;
An expansion device for expanding the refrigerant from the indoor heat exchanger;
An outdoor heat exchanger for evaporating the refrigerant from the expansion device during a heating operation;
An accumulator for separating and sending a gaseous refrigerant from the outdoor heat exchanger to the compressor;
A bypass flow passage configured to bypass at least a portion of the low temperature refrigerant from the indoor heat exchanger to exchange heat while passing through the accumulator during a heating operation;
And a control unit configured to control a flow rate of the refrigerant bypassed to the bypass passage so that a difference between a temperature of the refrigerant passing through the accumulator and a temperature of the refrigerant from the indoor heat exchanger is maintained at a preset value during the heating operation. Pump.
The method according to claim 1,
Further comprising a refrigerant passage for connecting the indoor heat exchanger and the outdoor heat exchanger,
The bypass flow passage branches from the refrigerant flow passage and passes through the accumulator, and is then connected to the refrigerant flow passage.
The method according to claim 2,
A heating flow rate control valve disposed in the coolant flow path and controlling a flow rate of the coolant bypassed to the bypass flow path during a heating operation;
The control unit is a heat pump for controlling the opening degree of the flow control valve for heating.
The method according to claim 1,
And a cooling flow rate control valve disposed in the bypass passage to control a flow rate of the refrigerant bypassed to the bypass passage among the refrigerant condensed in the outdoor heat exchanger during the cooling operation.
The method according to claim 3,
And a bypass flow path temperature sensor disposed in the bypass flow path and configured to measure a temperature of the refrigerant passing through the accumulator during heating operation.
The method according to claim 5,
And a coolant flow path temperature sensor disposed in the coolant flow path, the coolant flow path temperature sensor measuring a temperature of the coolant from the indoor heat exchanger during a heating operation.
delete The method according to claim 1,
The bypass flow path includes a refrigerant pipe inserted in the lower portion of the accumulator.

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