EP1626230B1

EP1626230B1 - Operation control method for unitary air conditioner

Info

Publication number: EP1626230B1
Application number: EP05101612A
Authority: EP
Inventors: Won-Hee Lee; Yoon-Jei Hwang; Seung-Youp Daerim 2-cha Woosung Apt.102-1303 Hyun; Jae-Hoon Sim
Original assignee: LG Electronics Inc
Current assignee: LG Electronics Inc
Priority date: 2004-08-14
Filing date: 2005-03-02
Publication date: 2011-08-10
Anticipated expiration: 2025-03-02
Also published as: EP1626230A3; US20060032252A1; CN1734384B; EP1626230A2; CN1734384A; KR20060015381A; KR100619733B1

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a unitary air conditioner, and more particularly, to an operation control method for a unitary air conditioner which improves the load response capabilities of compressors and improves energy efficiency and amenity.

2. Description of the Background Art

Generally, a unitary air conditioning system is a kind of centralized cooling and heating system which creates a hot air or hot air in one place using a cooling and heating system and supplies it to an individual space through a duct.
Fig. 1 is a schematic view illustrating a conventional unitary air conditioner of heat pump type using a cooling cycle.
Fig. 2 is a system view of the conventional unitary air conditioner of Fig. 1.
As shown in Figs. 1 and 2, the conventional unitary air conditioner comprises one outdoor unit 1 fixedly disposed outside a building, a cold and hot air unit 2 connected to a first exchange 1b of the outdoor unit 1 and fixedly disposed in the basement, outbuilding, etc. of the basement, an air supply duct 3 and an exhaust duct 4 connected by a refrigerant pipe to an air supplying opening and an exhaust opening, respectively, of the cold and hot air unit 2 and separately buried in the wall body of each floor of the building and region controllers 5a to 5d disposed in the middle of the air supply duct 3 and exhaust duct 4 and discriminating air supply and air exhaustion to each floor.
The outdoor unit 1 comprises one or more compressor 1a disposed inside a case and compressing a refrigerant gas, a firs heat exchange 1b connected to the compressor 1 a by a refrigerant pipe and condensing the refrigerant gas (in a cooling operation) or absorbing a latent heat (in a heating operation), an inflating device 1 c reducing and inflating the pressure of the refrigerant gas, and an outdoor fan (not shown) supplying an external air to the first heat exchange and increasing the heat exchange performance of the heat exchange 1b.
The cold and hot air unit 2 comprises a second heat exchange 2a disposed inside a case and connecting one end thereof to the first heat exchange 1b and the other end to the expansion device 1 c simultaneously and a supply ventilating fan (not shown) guiding a hot air or hot air to the air supply duct 3. Further, the case of the cold and hot air unit generally has an air channel of 'U' shape formed therein so as to receive the second heat exchange 2a and the supply ventilating fan (not shown), the air supply duct 3 and the exhaust duct 4 being connected respectively to the air supply side and exhaust side of the air channel.
The air supply duct 3 and the exhaust duct 4, as stated above, are connected to the air supplying opening and exhaust opening of the cold and hot air unit 2 and separately buried in corresponding regions Z1 and Z2. The air supply duct and 3 and the exhaust duct 4 are provided with a discharge opening 3a supplying cold air or hot air to the corresponding regions and a suction opening 4a sucking cold air or hot air to circulate indoor air.
The region controllers 5a to 5d are a kind of valves which are disposed in the middle of the air supply duct 3 and of the exhaust duct buried in the corresponding regions Z1 and Z2 so as to supply cold air or hot air to the corresponding regions separately. They are connected to a control section (not shown) so that they can be automatically turned on/off by detecting the temperature, humidity, etc. of the corresponding regions and comparing the detected values with set values, or they are configured to be operated manually.
Fig. 3 is an exemplified view illustrating the operating mode of a compressor being determined through a thermostat in the conventional unitary air conditioner.
As shown in Fig. 3, the unitary air conditioner conventionally commercialized operates the compressor in the minimum operation mode or in the maximum operation mode by controlling the indoor unit or outdoor unit by a low cold temperature or high cold temperature operation control signal provided from the thermostat.
For example, in case the unitary air conditioner is a single-stage model, it conducts only the operation (such as the maximum operation) set according to an operation control signal provided from the thermostat. Further, in case the unitary air conditioner is a two-stage model, when a high cold temperature operation control signal is provided from the thermostat, both indoor unit and outdoor unit conduct their operation in the minimum operation mode.
As described above, although the conventional unitary air conditioner uses two compressors, it operates only either the compressor in the minimum operation mode or in the maximum operation mode. Therefore, the conventional unitary air conditioner has the defect of decreasing the load response capabilities of the compressors and of increasing of power consumption by operating the compressors only in the two-stage operation mode.

US 2004/0107709 A1 discloses set-up of four compressors operated in three cooling modes.
US 2004/0118135 and US 2002/134094 A1 disclose schemes of addition of various compressors and analyzing their effect on the cooling capacity over a prolonged time before adjusting said capacity.
EP-0 543 622 A2 discloses usage of compressors with variable capacity to be adjusted according to the cooling needs.

SUMMARY OF THE INVENTION

Therefore, an object of the present invention is to provide an operation control method for a unitary air conditioner according to claim 1, which is able to improve the load response capabilities of compressors by operating the compressors in the three-stage operation mode upon driving one or more compressors.
It is another object of the present invention to provide an operation control method for a unitary conditioner which improves energy efficiency and amenity by checking the previous operation status of the compressors and determining the operation mode of the compressors based on the previous operation status.
There is provided an operation control method for a unitary air conditioner with two compressors, in accordance with the present invention, comprises the steps of: operating the compressors for a predetermined time by a user's selecting a low cold temperature cooling mode or a high cold temperature cooling mode; and operating the compressors in either the minimum operation mode or the intermediate operation mode according to a low cold temperature signal generated from a thermostat by the selection of the low cold temperature cooling mode.
There is provided an operation control method for a unitary air conditioner with two compressors, in accordance with the present invention, comprises the steps of: a user's selecting a low cold temperature cooling mode or a high cold temperature cooling mode; when a high cold temperature signal is inputted from a thermostat by selecting the high cold temperature cooling mode, operating the compressors in the maximum operation mode; and when a low cold temperature signal is inputted from the thermostat by selecting the low cold temperature cooling mode, checking the previous operation status based on the size of the load at the indoor side and operating the compressors in either the minimum operation mode or the intermediate operation mode.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.
In the drawings:

Fig. 1 is a schematic view illustrating a conventional unitary air conditioner of heat pump type using a cooling cycle;
Fig. 2 is a system view of the conventional unitary air conditioner involved with Fig. 2;
Fig. 3 is an exemplified view illustrating the operating mode of a compressor being determined through a thermostat in the conventional unitary air conditioner;
Fig. 4 is a flow chart of one embodiment of an operation control method for a unitary air conditioner in accordance with the present invention;
Figs. 5A and 5B are flow charts of another embodiment of an operation control method for a unitary air conditioner in accordance with the present invention;
Figs. 6A and 6B are flow charts of yet another embodiment of an operation control method for a unitary air conditioner in accordance with the present invention;
Fig. 7 is a graph illustrating the comparison of changes in indoor air temperature between the present invention and the conventional art; and
Fig. 8 is a comparison chart illustrating load response capabilities and power consumption with respect to the present invention and the conventional art.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, preferred embodiments relating to an operation control method for a unitary air conditioner with one or more compressor, which is able to increase the energy efficiency with a reduction of power consumption and improve the amenity a user feels with an improvement of response capabilities to a load, in accordance with the present invention will be described in detail with reference to the accompanying drawings. Although the embodiments of the present invention have been described with respect to a unitary air conditioner with two compressors having a different capacity from each other for convenience of explanation, it also may be applicable to a unitary air conditioner with one or more compressor.
A system for control the operation of a unitary air conditioner in accordance with the present invention may comprise two compressors with a different capacity, a heat exchange, a fan, a fan motor, an accumulator, etc. At this moment, in the present invention, a three-stage operation is conducted using two compressors with a different capacity while using a conventionally used two-stage thermostat as it is. In other words, the unitary air conditioner is operated in the maximum operation mode by operating both of the two compressors, or is operated in the intermediate operation mode (60% operation) by operating only the compressor with a large capacity out of the two compressors, or is operated in the minimum operation mode (40% operation) by operating only the compressor with a smaller capacity out of the two compressors.
The embodiments relating to the operation control method for a unitary air conditioner of the present invention in accordance with the aforementioned construction will be described below.
Fig. 4 is a flow chart of one embodiment of an operation control method for a unitary air conditioner in accordance with the present invention.
As shown in Fig. 4, the operation control method for a unitary air conditioner, the unitary air conditioner being provided with two compressors having a different capacity, in accordance with the present invention, comprises the steps of: operating one or two of the compressors for a predetermined time by a user's selecting a low cold temperature cooling mode or a high cold temperature cooling mode (S41); detecting a room temperature and comparing the room temperature with a desired temperature (S42 and S43); judging the size of a load at the indoor side based on the result of comparison between the room temperature and the desired temperature (S44); when a low cold temperature signal Y1 is inputted from a thermostat by selecting the low cold temperature cooling mode, checking the previous operation status based on the size of the load at the indoor side and operating the compressor in either the minimum operation mode or the intermediate operation mode (S46 and S47); when a high cold temperature signal Y2 is inputted from the thermostat by the user's selecting the cooling mode, operating both compressors in the maximum operation mode (S45). In other words, in the present invention, when a low cold temperature signal is generated from the thermostat, the size of the load at the indoor side is judged to thus determine the operation of the compressors in the minimum or intermediate operation mode, and the size of the load at the indoor side means a gap between the room temperature and the desired temperature. Further, the previous operation status is determined based on a gap between the room temperature and the desired temperature, an outdoor temperature or the like.
Therefore, in the operation control method for the unitary air conditioner in accordance with the present invention, when a low cold temperature signal is generated from the thermostat, the minimum operation mode allows to operate only the compressor with a smaller capacity out of the two compressors, and the intermediate operation mode allows to operate only the compressor with a larger capacity out of the two compressors. Hence, when the indoor side load is large, only the larger capacity compressor (60% operation) is used to thus increase the response capabilities to the load, or when the indoor side load is small, only the smaller capacity compressor (40% operation) is used to thus reduce the power consumption.
The embodiments of the operation control method for the unitary air conditioner will be described in more detail.
Figs. 5A and 5B are flow charts of another embodiment of an operation control method for a unitary air conditioner in accordance with the present invention.
As shown in Figs. 5A and 5B, upon an initial start-up, the unitary air conditioner generates a low cold temperature signal from a thermostat according to a user's selection of a cooling mode, and operates a larger capacity compressor (e.g., 60% operation) according to the low cold temperature signal (S51 to S53).
Thereafter, when a predetermined time elapses during which an indoor load is eliminated, a room temperature and a desired temperature are compared, and then when the thermostat generates a compressor on/off control signal Y2 for generating a low cold temperature based on the result of the comparison, both smaller capacity and large capacity compressors are operated (e.g., 100% operation) to thus eliminate the indoor load (S54 to S56).
Thereafter, when a predetermined time elapses since the smaller capacity and larger capacity compressors have been operated, a room temperature and a desired temperature are compared again, and then when the thermostat generates a compressor on/off signal Y1 for generating a low cold temperature signal based on the result of the comparison, the larger capacity compressor is operated (e.g., 60% operation) (S57 to S59).
When a predetermined time elapses since the larger capacity compressor has been operated, a room temperature and a desired temperature are compared, and then when the thermostat generates a compressor on/off control signal for stopping the operation of the compressor based on the result of the comparison, the operation of the larger capacity compressor is stopped (S60 to S62).
Thereafter, after the lapse of a predetermined time, when the thermostat generates a compressor on/off signal Y1 for generating a low cold temperature signal, the smaller capacity compressor is operated (S63 to S65). In other words, when the thermostat generates a stop signal after generating a low cold temperature signal Y1 and then generates a low cold temperature signal Y1 again, it is judged that the load is eliminated to some extent and thus only the smaller capacity compressor for executing the minimum operation is operated.
Since it is judged that the indoor load is eliminated to some extent afterwards, only the smaller capacity compressor is generated upon generating a low cold temperature signal Y1 (S66 and S67). That is, when a predetermined time elapses since the smaller capacity compressor has been operated, a room temperature and a desired temperature are compared, and then when the thermostat generates a compressor on/off control signal for stopping the operation of the compressor based on the result of the comparison, the operation of the smaller capacity compressor is stopped. Then, after a predetermined time, when the thermostat generates a compressor on/off signal for generating a low cold temperature signal Y1, the smaller capacity compressor is operated.
Meanwhile after a lapse of a predetermined time since the smaller capacity and larger capacity compressors have been operated (S56), a room temperature and a desired temperature are compared (S57). And, when the thermostat generates a compressor on/off control signal for stopping the operation of the compressors based on the result of the comparison, the operation of the larger capacity and smaller capacity compressors is stopped (S68) when a predetermined time elapses since the larger capacity and smaller capacity compressors are stopped, a room temperature and a desired temperature are compared, and then when the thermostat generates a compressor on/off control signal for generating a low cold temperature signal Y1 based on the result of the comparison, the larger capacity compressor is operated (S57 to S59). That is, when a low cold temperature signal is generated by the elimination of the load after a lapse of a predetermined time since the larger capacity compressor and the smaller capacity compressor have been operated according to a high cold temperature signal, or when a low cold temperature signal is generated after the compressors are stopped for a predetermined time, the larger capacity compressor is operated to eliminate the load.
According to yet another embodiment of the present invention, the thermostat may generate a high cold temperature signal at an early stage. The algorithm of this embodiment of the present invention which generates a high cold temperature signal at an early stage will be described below.
Figs. 6A and 6B are flow charts of yet another embodiment of an operation control method for a unitary air conditioner in accordance with the present invention.
As shown in Figs. 6A and 6B, when the cooling mode is selected by a user, the thermostat generates a high cold temperature signal, and operates smaller capacity and larger capacity compressors according to the high cold temperature signal (S81 to S83).
When a predetermined time elapses since the smaller capacity and larger capacity compressors have been operated, a room temperature and a desired temperature are compared, and then when the thermostat generates a compressor on/off control signal for stopping the operation of the compressors based on the result of the comparison, the operation of the smaller capacity and larger capacity compressors is stopped (S84 to S86).
Thereafter, when a predetermined time elapses since the smaller capacity and larger capacity compressors have been stopped, a room temperature and a desired temperature are compared, and then when the thermostat generates a compressor on/off control signal for generating a low cold temperature signal based on the result of the comparison, the larger capacity compressor is operated (S87 to S89).
When a predetermined time elapses since the smaller capacity and larger capacity compressors have been operated (S83), a room temperature and a desired temperature are compared (S84), and then when the thermostat generates a compressor on/off control signal for generating a low cold temperature signal based on the result of the comparison, the operation of the larger capacity compressor is stopped (S88 to S89).
Next, when a predetermined time elapses since the larger capacity compressor has been operated, a room temperature and a desired temperature are compared, and then when the thermostat generates a compressor on/off control signal for stopping the operation of the compressor based on the result of the comparison, the operation of the larger capacity compressor is stopped (S90 to S92).
After a predetermined time, a room temperature and a desired temperature are compared again, and then when the thermostat generates a compressor on/off control signal for generating a low cold temperature signal based on the result of the comparison, the operation of the smaller capacity compressor is stopped (S93 to S95).
Thereafter, when the user enters a cooling mode end signal, the operation of the compressor is finished (S96).
Fig. 7 is a graph illustrating the comparison of changes in indoor air temperature between the present invention and the conventional art.
As shown in Fig. 7, it can be seen that the unitary air conditioner using a three-stage algorithm in accordance with the present invention has an overally smaller gradient of indoor temperature than the conventional art. This makes the user feel pleasant with the improvement of the compressors' load response capabilities.
Fig. 8 is a comparison chart illustrating load response capabilities and power consumption with respect to the present invention and the conventional art.
As shown in Fig. 8, it can be seen that the unitary air conditioner using the three-stage algorithm in accordance with the present invention increases the energy efficiency with a reduction of power consumption and improves the amenity with an improvement of response capabilities to a load.
As described in detail above, the present invention has the effect of improving the load response capabilities of the compressors by operating the compressors in the three-stage operation mode upon driving one or more compressors. Further, the present invention has the effect of improving energy efficiency and amenity with a reduction of power consumption since the operation mode of the compressors is determined by judging the previous operation status according to the size of the load at the indoor side upon a low cold temperature operation.
The invention is solely limited by the appended claims.

Claims

An operation control method for a unitary air conditioner with three operation modes, consisting of high, intermediate and low operation mode, with two compressors, including a smaller capacity compressor and a larger capacity compressor comprising the steps of:
operating the compressors for a predetermined time by a user's selection of a low cold temperature cooling mode or a high cold temperature cooling mode;

and operating the compressors in either a minimum operation mode or an intermediate operation mode when a low cold temperature signal is inputted from a thermostat by the selection of the low cold temperature cooling mode,

characterized in that

the thermostat is a two-stage thermostat, and

the minimum operation mode allows to operate only the compressor with a smaller capacity out of the two compressors, and the intermediate operation mode allows to operate only the compressor with a larger capacity out of the two compressors and

operating both the smaller capacity and the larger capacity compressors in the maximum operation mode when a high cold temperature signal is inputted from the thermostat by the selection of the high cold temperature cooling mode, and

when a low cold temperature signal is generated from said thermostat, the size of the load at the indoor side is judged to thus determine the operation of the compressors in the minimum or Intermediate operation mode, and the size of the load at the indoor side means a gap between the room temperature and the desired temperature.

when a low cold temperature signal is generated from said thermostat, the size of the load at the Indoor side is judged to thus determine the operation of the compressors in the minimum or intermediate operation mode, and the size of the load at the indoor side means a gap between the room temperature and the desired temperature and

wherein the step of operating the compressors according to a low cold temperature signal from the thermostat further comprises the step of checking the previous operation status of the cooling mode.
The method of claim 1, wherein the previous operation status is determined based on a gap between a room temperature and a desired temperature or an outdoor temperature.
The method of claim 2, wherein, when the load at the indoor side is large, the load response capabilities is increased using only the larger capacity compressor out of the two compressors.
The method of claim 2, wherein, when the load at the indoor side is small, the power consumption is reduced using only the smaller capacity compressor out of the two compressors.
The method of claim 1, wherein upon an initial start-up, the unitary air conditioner generates the low cold temperature signal from the thermostat according to a user's selection of a cooling mode, and operates a larger capacity compressor according to the low cold temperature signal (S51 to S53) and
after a predetermined time elapses during which an Indoor load is eliminated, a room temperature and a desired temperature are compared, and
then when the thermostat generates a compressor on/off control signal Y2 for generating a low cold temperature based on the result of the comparison, both smaller capacity and large capacity compressors are operated.
The method of claim 5, wherein when a predetermined time elapses since the smaller capacity and larger capacity compressors have been operated, a room temperature and a desired temperature are compared again, and then when the thermostat generates a compressor on/off signal Y1 for generating the low cold temperature signal based on the result of the comparison, the larger capacity compressor is operated.
The method of claim 6, wherein comparing a room temperature and a desired temperature after operating the larger capacity compressor for a predetermined time, a room temperature and a desired temperature are compared, and when the thermostat generates a compressor on/off control signal for stopping the operation of the larger capacity compressor based on the result of the comparison, the operation of the larger capacity compressor is stopped (S60 to S62).
The method of claim 7, wherein after the lapse of a predetermined time, when the thermostat generates a compressor on/off signal Y1 for generating the low cold temperature signal, the smaller capacity compressor is operated (S63 to S65).
The method of claim 8, further comprising the steps of:
comparing a room temperature and a desired temperature after operating the smaller capacity and the larger capacity compressors for a predetermined time; and when the thermostat generates a compressor on/off control signal for stopping the operation of the smaller capacity and larger capacity compressors based on the result of the comparison, stopping the operation of the smaller capacity and larger capacity compressors.
The method of claim 9, further comprising the steps of:
comparing a room temperature and a desired temperature after operating the smaller capacity and the larger capacity compressors for a predetermined time; and when the thermostat generates a compressor on/off control signal for generating a low cold temperature signal based on the result of the comparison, operating the larger capacity compressor.
The method of claim 1, wherein when generating a high cold temperature signal from a thermostat when a cooling mode is selected all of the compressors are operated according to the high cold temperature signal (S81 - S83); and
when a predetermined time elapses since the smaller capacity and larger capacity compressors have been operated, a room temperature and a desired temperature are compared, and then when the thermostat generates a compressor on/off control signal for stopping the operation of the compressors based on the result of the comparison, the operation of the smaller capacity and larger capacity compressors is stopped (S84 to S86); and
comparing a room temperature and a desired temperature after a predetermined time; and when the thermostat generates a compressor on/off control signal for generating a low cold temperature signal based on the result of the comparison, the larger capacity compressor out of the two compressors is operated (S87 - S89).
The method of claim 11, further comprising the steps of:
comparing a room temperature and a desired temperature after operating the smaller capacity and larger capacity compressors for a predetermined time; and when the thermostat generates a compressor on/off control signal for generating the low cold temperature signal based on the result of the comparison, operating the larger capacity compressor.