US20140366564A1

US20140366564A1 - Air-conditioning apparatus and method for controlling same

Info

Publication number: US20140366564A1
Application number: US14/364,114
Authority: US
Inventors: Eunjun Cho; Beomsoo Seo
Original assignee: LG Electronics Inc
Current assignee: LG Electronics Inc
Priority date: 2011-12-14
Filing date: 2012-12-14
Publication date: 2014-12-18
Also published as: EP2801765A4; CN103988027B; WO2013089484A1; EP2801765A1; KR101832765B1; EP2801765B1; KR20130067935A; CN103988027A

Abstract

The present invention relates to an air-conditioning apparatus which is capable of performing a cooling operation in a stable manner in an environment having a low outside temperature. The air-conditioning apparatus according to the present invention comprises: a housing including an inlet, a bypass inlet, and an outlet; a fan configured to introduce air into the housing and discharge the air from the housing; a heat-exchange flow path deposed between the inlet and the outlet; a heat exchanger disposed at the heat exchange flow path; and a bypass flow path disposed between the bypass inlet and the outlet.

Description

TECHNICAL FIELD

The present invention relates to an air conditioning apparatus, and more particularly to an air conditioning apparatus which is capable of performing a cooling operation in a stable manner under an environment having a low outside temperature.

BACKGROUND ART

In general, an air conditioning apparatus is designed to cool or warm an indoor space, such as a residence, a restaurant, an office or the like.
In addition, such an air conditioning apparatus may include an outdoor unit installed in an outdoor space and an indoor unit installed in an indoor space. The outdoor unit may include a compressor for compression of refrigerant, an outdoor heat exchanger for heat exchange between outdoor air and refrigerant, a blowing fan and various pipes for connection between the compressor and the indoor unit. The indoor unit may include an indoor heat exchanger for heat exchange between indoor air and refrigerant and an expansion valve.
Meanwhile, in a case in which an outdoor unit is connected to a plurality of indoor units, in order to increase heat exchange area, the outdoor unit is provided with a large-scale outdoor heat exchanger. A compressor, an oil separator, an accumulator and the like for compression of refrigerant circulating in an air conditioning cycle, a fan for forced flow and a motor for rotation of the fan are mounted to the outdoor unit. In addition, a plurality of refrigerant pipes is received in the outdoor unit to interconnect the aforementioned components thereof and the indoor units.
FIG. 1 is a perspective view showing a conventional outdoor unit, and FIG. 2 is a view for explanation of an operational state of a fan included in the conventional outdoor unit.
Referring to FIG. 1, an outdoor unit 20 includes a housing 21 defining an external appearance of the outdoor unit, and the housing 21 has an inlet 22 and an outlet 23. A heat exchanger 24 is placed in the housing 21 near the inlet 22. In this case, air introduced through the inlet 22 is subjected to heat exchange with refrigerant while passing through the heat exchanger 24 and, thereafter, is discharged outward through the outlet 23.
Meanwhile, referring to FIG. 2, in a case in which the outdoor unit 20 performs a cooling operation under an environment having a low outside temperature (for example, −5° C.). , the condensation temperature or condensation pressure of refrigerant flowing in the heat exchanger is reduced, which prevents efficient operation of the compressor.
In this case, to adjust cooling load, the conventional outdoor unit is designed to reduce the flow rate of air introduced through the inlet 22 by reducing revolutions per minute (hereinafter referred to as RPM) of the fan.
However, when the RPM of the fan is reduced to a given RPM or less, only iterative ON/OFF control is possible due to an operation limit at low RPM. Existence of such a discontinuous control section causes hunting F1 of the condensation temperature or evaporation temperature of refrigerant in a cooling cycle, which problematically makes it impossible to provide inhabitants with pleasant cooling.

DISCLOSURE

Technical Problem

An object of the present invention is to provide an air conditioning apparatus which is capable of performing a cooling operation in a stable manner under an environment having a low outside temperature.
In addition, another object of the present invention is to provide an air conditioning apparatus which is capable of continuously controlling the flow rate of air passing through a heat exchanger even during a discontinuous control section of a fan.
In addition, a further object of the present invention is to provide an air conditioning apparatus which is capable of preventing high pressure drop due to sudden increase in the flow rate of air introduced into a heat exchanger.

Technical Solution

In accordance with one aspect of the present invention, the objects of the present invention can be achieved by providing an air conditioning apparatus including a housing including an inlet, a bypass inlet and an outlet, a fan configured to introduce air into the housing and to discharge the air from the housing, a heat exchange flow path defined between the inlet and the outlet, a heat exchanger located in the heat exchange flow path, and a bypass flow path defined between the bypass inlet and the outlet.
In accordance with another aspect of the present invention, there is provided an air conditioning apparatus including an outdoor unit and one or more indoor units connected to the outdoor unit, wherein the outdoor unit includes a housing including an inlet, a bypass inlet and an outlet, a fan configured to introduce air into the housing through the inlet and the bypass inlet and to discharge the air from the housing through the outlet, and a controller configured to control driving of the fan.
Here, the inlet may be in indirect communication with the outlet through a heat exchanger and the bypass inlet may be in direct communication with the outlet. The controller may vary the flow rate of air introduced through the inlet by adjusting the flow ate of air introduced through the bypass inlet.
In accordance with a further aspect of the present invention, there is provided a control method of an air conditioning apparatus, the control method including sensing a condensation pressure or condensation temperature of refrigerant in an outdoor unit, implementing constant speed operation of a fan in which a fan motor of the outdoor unit is controlled so as to be operated at minimum control RPM and the flow rate of air introduced into a heat exchanger is varied when the sensed result is below a first predetermined value, and implementing variable speed operation of the fan in which the fan motor of the outdoor unit is controlled so as to be operated at RPM exceeding the minimum control RPM when the sensed result is the first predetermined value or more.

Advantageous Effects

As is apparent from the above description, an air conditioning apparatus according to one embodiment of the present invention is configured to perform a cooling operation in a stable manner under an environment having a low outside temperature.
In addition, an air conditioning apparatus according to one embodiment of the present invention is configured to continuously control the flow rate of air passing through a heat exchanger even during a discontinuous control section of a fan.
In addition, an air conditioning apparatus according to one embodiment of the present invention is configured to prevent high pressure drop due to sudden increase in the flow rate of air introduced into a heat exchanger.

DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view showing a conventional outdoor unit.

FIG. 2 is a view for explanation of an operational state of a fan included in the conventional outdoor unit.

FIG. 3 is a block diagram showing configuration of an air conditioning apparatus according to one embodiment of the present invention.

FIG. 4 is a perspective view of the air conditioning apparatus according to one embodiment of the present invention.

FIG. 5 is a conceptual view for explanation of inlet flow to the air conditioning apparatus according to one embodiment of the present invention.

FIG. 6 is a view for explanation of an operational state of a fan included in the air conditioning apparatus according to one embodiment of the present invention.

FIG. 7 is a perspective view of an air conditioning apparatus according to another embodiment of the present invention.

FIG. 8 is a flowchart showing a control method of the air conditioning apparatus according to one embodiment of the present invention.

BEST MODE

Hereinafter, an air conditioning apparatus according to one embodiment of the present invention will be described in detail with reference to the accompanying drawings. It is to be understood that the accompanying drawings which illustrate the exemplary configuration of the present invention is merely given for more detailed description of the present invention and is not intended to limit the technical scope of the present invention.
In addition, the same or similar elements are denoted by the same reference numerals even though they are depicted in different drawings and a repeated description thereof will be omitted. For convenience of description, in the drawings, sizes and shapes of respective constituent members may be exaggerated or reduced.
Meanwhile, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms and are used simply to discriminate any one element from other elements.
FIG. 3 is a block diagram showing configuration of an air conditioning apparatus according to one embodiment of the present invention, FIG. 4 is a perspective view of the air conditioning apparatus according to one embodiment of the present invention, and FIG. 5 is a conceptual view for explanation of inlet flow to the air conditioning apparatus according to one embodiment of the present invention.
The air conditioning apparatus according to one embodiment of the present invention may include an outdoor unit 300 installed in an outdoor space and an indoor unit 500 installed in an indoor space. The outdoor unit 300 may include a compressor 200 for compression of refrigerant, an outdoor heat exchanger 320 for heat exchange between outdoor air and refrigerant, a fan (not shown), a fan motor 350 to drive the fan and various pipes (not shown) for connection between the compressor 200, the outdoor heat exchanger 320 and the indoor unit 500. The pipes are provided with temperature sensors and pressure sensors which are capable of measuring the temperature and pressure of refrigerant.
In addition, the indoor unit 500 may include an indoor heat exchanger (not shown) for heat exchange between indoor air and refrigerant, an expansion valve (not shown), a fan (not shown) and a fan motor 550 to drive the fan.
In addition, the air conditioning apparatus includes a controller 100 to control operations of the outdoor unit 300 and the indoor unit 500.
Meanwhile, the air conditioning apparatus according to one embodiment of the present invention includes a refrigeration cycle consisting of the compressor 200, the outdoor heat exchanger 320, the expansion valve and the indoor heat exchanger.
Considering the refrigeration cycle in detail, gas-phase refrigerant compressed in the compressor is introduced into the outdoor heat exchanger and changed into liquid-phase refrigerant. The refrigerant radiates heat outward during phase change in the outdoor heat exchanger. Thereafter, the refrigerant discharged from the outdoor heat exchanger is expanded while passing through the expansion valve and then introduced into the indoor heat exchanger.
Thereafter, the liquid-phase refrigerant introduced into the indoor heat exchanger is changed into gas-phase refrigerant. Likewise, the refrigerant absorbs outside heat during phase change in the indoor heat exchanger.
In this document, the air conditioning apparatus may be both an outdoor unit and an indoor unit or may be only an outdoor unit. Hereinafter, for convenience of description, the air conditioning apparatus will be limitedly described with reference to an outdoor unit alone.
The air conditioning apparatus 300 according to one embodiment of the present invention includes a housing 310 including an inlet 311, a bypass inlet 313 and an outlet 312, a fan configured to introduce air into the housing 310 and to discharge the air from the housing 310, a heat exchange flow path defined between the inlet 311 and the outlet 312, the heat exchanger 320 located in the heat exchange flow path and a bypass flow path defined between the bypass inlet 313 and the outlet 312.
The housing 310 has at least one inlet 311 through which outside air is introduced and moved to the heat exchanger 320. In one embodiment, a pair of inlets 311 may be formed respectively in both lateral surfaces of the housing 310. In addition, the housing 310 has the outlet 312 through which air moved by the fan is discharged. In one embodiment, a plurality of outlets 312 may be formed in an upper surface of the housing 310.
At least one heat exchanger 320 may be arranged in a lower space of the housing 310, and at least one fan may be arranged in an upper space. In addition, a pair of heat exchangers 320 may be located in the housing 310 near both lateral ends of the housing so as to correspond to the inlets 311 respectively. The heat exchangers may have an “L”-shaped or “U”-shaped form in order to increase heat exchange area.
Here, the heat exchange flow path refers to a path defined between the inlet 311 and the outlet 312. Air introduced through the inlet 311 is subjected to heat exchange with refrigerant while passing through the heat exchanger 320.
In addition, the housing 310 has at least one bypass inlet 313. Air introduced through the bypass inlet 313 does not directly pass through the heat exchanger 320. Accordingly, in a case in which the inlets 311 are formed respectively in both lateral surfaces of the housing 310, the bypass inlet 313 may be formed in a front surface of the housing 310.
Here, the bypass flow path is defined between the bypass inlet 311 and the outlet 312. Although some of the air introduced through the bypass inlet 311 may move to the heat exchanger 320, most of the air is discharged through the outlet 312 without passing through the heat exchanger 320.
The inlet 311 and the bypass inlet 313 differ from each other in terms of positions thereof relative to the heat exchanger. More specifically, since the heat exchanger 320 is positioned at the inlet 311, the heat exchanger 320 serves as a resistor with respect to air introduced through the inlet 311 when both the inlet 311 and the bypass inlet 313 are open. Therefore, the flow rate of air introduced through the inlet 311 is reduced as compared to a case in which the bypass inlet 313 is closed.
Accordingly, the air conditioning apparatus according to one embodiment of the present invention may control the flow rate of air introduced through the inlet 311 by adjusting the flow rate of air introduced through the bypass inlet 313, and consequently may adjust the flow rate of air that is subjected to heat exchange while passing through the heat exchangers 320, which may result in adjustment of cooling load.
To this end, the air conditioning apparatus 300 according to one embodiment of the present invention may include a bypass blocking device 330 to selectively open or close the bypass inlet 331. When the bypass blocking device 330 opens the bypass inlet 313, the flow rate of air introduced through the inlet 311 may be reduced. When the bypass blocking device 330 closes the bypass inlet 313, the flow rate of air introduced through the inlet 311 may be increased.
In addition, the air conditioning apparatus 300 according to one embodiment of the present invention may include a bypass vane 331 to adjust an opening degree of the bypass inlet. The bypass vane 331 may adjust an opening degree of the bypass inlet 313, thereby reducing the flow rate of air introduced through the inlet 311 when increasing the opening degree and increasing the flow rate of air introduced through the inlet 311 when reducing the opening degree.
In addition, the bypass blocking device 330 may take the form of the bypass vane 331, and the bypass blocking device 330 and/or the bypass vane 331 may be controlled by the aforementioned controller 100.
FIG. 6 is a view for explanation of an operational state of the fan included in the air conditioning apparatus according to one embodiment of the present invention.
As described above, when the conventional outdoor unit 20 as described above performs a cooling operation under an environment having a low outside temperature (for example, −5° C.), the condensation temperature or condensation pressure of refrigerant moving in the heat exchanger is reduced, which prevents efficient operation of the compressor.
In this case, the conventional outdoor unit adjusts cooling load by reducing revolutions per minute (hereinafter referred to as RPM) of the fan to reduce the flow rate of air introduced through the inlet 22.
However, when the RPM of the fan is reduced to a given RPM or less, only iterative ON/OFF control is possible due to an operation limit at low RPM. Existence of such a discontinuous control section causes hunting Fl of the condensation temperature or evaporation temperature of refrigerant in a cooling cycle, which problematically makes it impossible to provide inhabitants with pleasant cooling (see FIG. 2).
Meanwhile, the aforementioned controller 100 controls the RPM of the fan motor 350 that drives the fan. The controller controls the RPM of the fan motor 350 based on the condensation pressure or condensation temperature of refrigerant.
In this case, under control of the controller 100, the bypass inlet 311 may be opened when the fan motor 350 is operated at the minimum control RPM.
More specifically, differently from a conventional case in which the fan is reduced in RPM and stops operation thereof (minimum RPM control) under an environment having a low outside temperature (for example, −5° C.), the air conditioning apparatus 300 according to the present invention may adjust the flow rate of air introduced through the bypass inlet 313 without stopping operation of the fan, thereby adjusting the flow rate of air introduced into the heat exchanger 320.
Referring to FIG. 2, the conventional air conditioning apparatus has a discontinuous control section of the fan including a time t1 during which the fan is operated under an environment having a low outside temperature and a time t2 during which the fan stops. On the other hand, referring to FIG. 6, it will be appreciated that the air conditioning apparatus 300 according to the present invention exhibits an increased time t3 during which the fan is operated even under an environment having a low outside temperature, resulting in reduced hunting F2 of the condensation temperature or evaporation temperature.
In this way, the air conditioning apparatus 300 according to the present invention may perform a cooling operation in a stable manner even under an environment having a low outside temperature, may continuously control the flow rate of air passing through the heat exchanger 320 even during a discontinuous control section of the fan, and may adjust cooling load.
FIG. 7 is a perspective view of an air conditioning apparatus according to another embodiment of the present invention.
Referring to FIG. 7, the air conditioning apparatus 300 may further include a cover 340 to prevent outside air from being directly introduced into the inlet 311 in a direction perpendicular to the inlet. The cover 340 functions to prevent high pressure drop due to sudden increase in the flow rate of air introduced into the heat exchanger 320.
In one embodiment, the cover 340 may have a cover top inlet 324 and a cover lateral inlet 343, and may include a main body 341 configured to bypass air, directly introduced in a direction perpendicular to the inlet 311, to the cover top inlet 342 and the cover lateral inlet 343.
In addition, the air conditioning apparatus according to the present embodiment may include the outdoor unit 300 and one or more indoor units 500 connected to the outdoor unit.
Here, the outdoor unit 300, as described above, may include the housing 310 including the inlet 311, the bypass inlet 313 and the outlet 312, the fan configured to introduce air into the housing 310 through the inlet 311 and the bypass inlet 313 and to discharge the air from the housing 310 through the outlet 312 and the controller 100 to control driving of the fan.
In addition, the inlet 311 is in indirect communication with the outlet 312 through the heat exchanger 320, the bypass inlet 313 is in direct communication with the outlet 312, and the controller 100 varies the flow rate of air introduced through the inlet 311 by adjusting the flow rate of air introduced through the bypass inlet 313.
In this case, as described above, the controller 100 may control driving of the fan based on the condensation pressure or condensation temperature of refrigerant. The outdoor unit may include the bypass vane 331 which functions to selectively open or close the bypass inlet 313 and to adjust an opening degree of the bypass inlet.
In addition, the controller 100 may control the bypass vane 331 such that the bypass vane 331 is operated when the fan is driven at the minimum control PRM.
Hereinafter, a control method of the air conditioning apparatus 300 having the above-described configuration will be described in detail with reference to the accompanying drawings.
FIG. 8 is a flowchart showing a control method of an air conditioning apparatus according to one embodiment of the present invention.
The control method of the air conditioning apparatus according to one embodiment of the present invention includes sensing the condensation pressure or condensation temperature of refrigerant in an outdoor unit (S3), implementing constant speed operation of a fan in which a fan motor of the outdoor unit is controlled so as to be operated at minimum control RPM and the flow rate of air introduced into a heat exchanger is varied when the sensed result is below a first predetermined value (S5) and implementing variable speed operation of the fan in which the fan motor of the outdoor unit is controlled so as to be operated at RPM exceeding the minimum control RPM when the sensed result is the first predetermined value or more (S4).
In this case, in the constant speed operation of the fan S5, varying the flow rate of bypassed air that is not subjected to heat exchange is possible. During the constant speed operation of the fan S5, the sensed result may be compared with a second predetermined value (S6). When the sensed result is below the second predetermined value, operation of the fan stops (S7).
More specifically, when a cooling operation starts (S1) and thereafter an outdoor temperature is reduced during the cooling operation, the outdoor unit senses the condensation pressure or condensation temperature of refrigerant (S3). In this case, when the condensation pressure or condensation temperature of refrigerant is the first predetermined value or more, the variable speed operation of the fan S4 in which the RPM of the fan is varied to adjust the flow rate of air introduced into the heat exchanger is implemented.
Differently, when the condensation pressure or condensation temperature of refrigerant is below the first predetermined value, the flow rate of air introduced into the heat exchanger cannot be adjusted by varying the RPM of the fan. In this case, the constant speed operation of the fan S5 may be implemented without stopping operation of the fan. As described above, the flow rate of air introduced into the heat exchanger may be adjusted by varying the flow rate of bypassed air that is not subjected to heat exchange.
Meanwhile, the sensed result may be compared with the second predetermined value (S6) during the constant speed operation of the fan S5. When the sensed result is below the second predetermined value, operation of the fan stops (S7).
As described above, an air conditioning apparatus according to one embodiment of the present invention is configured to perform a cooling operation in a stable manner under an environment having a low outside temperature.
In addition, an air conditioning apparatus according to one embodiment of the present invention is configured to continuously control the flow rate of air passing through a heat exchanger even during a discontinuous control section of a fan.
In addition, an air conditioning apparatus according to one embodiment of the present invention is configured to prevent high pressure drop due to sudden increase in the flow rate of air introduced into a heat exchanger.
The exemplary embodiments of the present invention as described above are disclosed for illustrative purpose, and those skilled in the art will appreciate that various modifications, variations and additions can be made within spirit or scope of the present invention and these modifications, variations and additions fall in the following claims.

Claims

1. An air conditioning apparatus comprising:

a housing including an inlet, a bypass inlet and an outlet;

a fan configured to introduce air into the housing and to discharge the air from the housing;

a heat exchange flow path defined between the inlet and the outlet;

a heat exchanger located in the heat exchange flow path; and

a bypass flow path defined between the bypass inlet and the outlet.

2. The apparatus according to claim 1, further comprising a bypass blocking device configured to selectively open or close the bypass inlet.

3. The apparatus according to claim 1, further comprising a bypass vane configured to adjust an opening degree of the bypass inlet.

4. The apparatus according to claim 1, further comprising a controller configured to control revolutions per minute (RPM) of a fan motor, the fan motor serving to drive the fan.

5. The apparatus according to claim 4, wherein the controller controls the RPM of the fan motor based on a condensation pressure or condensation temperature of refrigerant.

6. The apparatus according to claim 5, wherein the controller controls the fan motor so as to be operated at minimum control RPM when the condensation pressure or condensation temperature is below a first predetermined value, and

wherein the controller controls the fan motor to stop operation thereof when the condensation pressure or condensation temperature is below a second predetermined value, the second predetermined value being less than the first predetermined value.

7. The apparatus according to claim 5, further comprising a bypass vane configured to selectively open or close the bypass inlet and to adjust an opening degree of the bypass inlet.

8. The apparatus according to claim 7, wherein the controller controls the bypass vane to open the bypass inlet when the fan motor is operated at minimum control RPM.

9. The apparatus according to claim 8, wherein the controller increases the opening degree of the bypass inlet when the fan motor is operated at the minimum control RPM, thereby increasing the flow rate of air introduced through the bypass inlet and reduces the flow rate of air introduced through the inlet.

10. The apparatus according to claim 1, further comprising a cover configured to prevent outside air from being directly introduced into the inlet in a direction perpendicular to the inlet.

11. The apparatus according to claim 10, wherein the cover has a cover top inlet and a cover lateral inlet and includes a main body configured to bypass the air, directly introduced in the direction perpendicular to the inlet of the housing, to the cover top inlet and the cover lateral inlet.

12. An air conditioning apparatus comprising an outdoor unit and one or more indoor units connected to the outdoor unit,

wherein the outdoor unit comprises:

a housing including an inlet, a bypass inlet and an outlet;

a fan configured to introduce air into the housing through the inlet and the bypass inlet and to discharge the air from the housing through the outlet; and

a controller configured to control driving of the fan,

wherein the inlet is in indirect communication with the outlet through a heat exchanger and the bypass inlet is in direct communication with the outlet, and

wherein the controller varies the flow rate of air introduced through the inlet by adjusting the flow ate of air introduced through the bypass inlet.

13. The apparatus according to claim 12, wherein the controller controls driving of the fan based on a condensation pressure or condensation temperature of refrigerant.

14. The apparatus according to claim 12, further comprising a bypass vane configured to selectively open or close the bypass inlet and to adjust an opening degree of the bypass inlet.

15. The apparatus according to claim 14, wherein the controller controls the bypass vane so as to be operated when a fan motor is operated at minimum control RPM.

16. A control method of an air conditioning apparatus, the control method comprising:

sensing a condensation pressure or condensation temperature of refrigerant in an outdoor unit;

implementing constant speed operation of a fan in which a fan motor of the outdoor unit is controlled so as to be operated at minimum control RPM and the flow rate of air introduced into a heat exchanger is varied when the sensed result is below a first predetermined value; and

implementing variable speed operation of the fan in which the fan motor of the outdoor unit is controlled so as to be operated at RPM exceeding the minimum control RPM when the sensed result is the first predetermined value or more.

17. The control method according to claim 16, wherein, in the constant speed operation of the fan, the flow rate of bypassed air not subjected to heat exchange is varied.

18. The control method according to claim 17, wherein, in the constant speed operation of the fan, the flow rate of bypassed air through the bypass inlet is increased to reduce the flow rate of air introduced into the heat exchanger through the inlet.

19. The control method according to claim 16, wherein operation of the fan stops during the constant speed operation of the fan when the sensed result is below a second predetermined value.