Air conditioning system

An air conditioning system can automatically increase or decrease a desired temperature of an indoor unit at a variable gradient smaller than the variable gradient per predetermined time of an outdoor temperature. Hence, the user does not have to directly change the desired temperature, thus increasing user's convenience. Also, in the event of a significant diurnal range in temperature, air conditioning sickness can be prevented since an optimum indoor temperature can be maintained. Moreover, the variable gradient of the desired temperature of a room is smaller than the variable gradient of an outdoor temperature, thus keeping the room pleasant.

This nonprovisional application claims priority under 35 U.S.C. §119(a) on Patent Application No. 10-2007-0135501 filed in Republic of Korea on Dec. 21, 2007, the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an air conditioning system, and more particularly, to an air conditioning system, which can automatically increase or decrease a desired temperature of an indoor unit based on an increase or decrease in outdoor temperature.

2. Description of the Conventional Art

Generally, air conditioner is provided for cooling, heating, and air cleaning, and installed so as to discharge cool/warm air to a room and clean indoor air, thereby providing people with a more pleasant indoor environment. The air conditioner is separated into an indoor unit comprised of a heat exchanger and an outdoor unit comprised of a compressor, a heat exchanger, and so on for control purpose. Recently, there has been a wide spread of a multi-type air conditioner which is controlled by comprising an outdoor unit and a plurality of indoor units sharing the outdoor unit on one floor or in one building in order to enhance energy efficiency. Such a multi-type air conditioner uses a power divider in order to distribute power to the respective indoor units.

However, in the conventional air conditioner, a desired temperature inputted by a user or by the initial setting of the air conditioner is fixed at the time of applying power and setting a driving operation. In the event of a significant diurnal range in temperature, the difference between an indoor temperature and an outdoor temperature is not properly maintained, and this may cause an air conditioning sickness. If the desired temperature is changed during operation, the user has to directly manipulate the air conditioner to change the desired temperature, thereby increasing user's inconvenience.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an air conditioning system, which can automatically increase or decrease a desired temperature of an indoor unit based on an increase or decrease in outdoor temperature.

The present invention provides an air conditioning system, which comprises a remote controller, the remote controller comprising: an air conditioner including at least one indoor unit; an outdoor temperature detection unit for detecting an outdoor temperature of the place where the indoor unit is installed; and a control unit for calculating a deviation temperature having a predetermined deviation from the outdoor temperature detected in the outdoor temperature detecting unit, wherein the control unit varies the deviation between the outdoor temperature and the deviation temperature.

The air conditioning system according to the present invention can automatically increase or decrease a desired temperature of an indoor unit at a variable gradient smaller than the variable gradient per predetermined time of an outdoor temperature. Hence, the user does not have to directly change the desired temperature, thus increasing user's convenience. Also, in the event of a significant diurnal range in temperature, air conditioning sickness can be prevented since an optimum indoor temperature can be maintained. Moreover, the variable gradient of the desired temperature of a room is smaller than the variable gradient of an outdoor temperature, thus keeping the room pleasant.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1is a block diagram showing the configuration of an air conditioning system in accordance with one embodiment of the present invention.FIG. 2is a block diagram showing the internal configuration of a remote controller as shown inFIG. 1.

Referring toFIG. 1, the air conditioning system100of the present invention includes an air conditioner140and a remote controller150. The air conditioner140includes at least one indoor unit130and an outdoor unit120. While the air conditioner140includes one outdoor unit120and one indoor unit130, the present invention is not limited thereto. The air conditioner140may include one outdoor unit120and a plurality of indoor units130, or include a plurality of outdoor units120and a plurality of indoor units130. Each indoor unit130is provided with an indoor temperature sensor135for detecting an indoor temperature of the place where the indoor unit is placed and an outdoor temperature detecting unit136for detecting an outdoor temperature of the place where the indoor unit130is installed. The outdoor temperature detecting unit136may be an outdoor temperature sensor which is provided separately for each indoor unit130and attached to the outside of the indoor unit130to detect an outdoor temperature.

The indoor units130are respectively disposed in indoor spaces, and the outdoor unit120is disposed in an outdoor space. The indoor units130and the outdoor unit120are communicatively connected to each other via a network161. RS-485 communication is performed over the network161. However, the present invention is not limited to the above communication method.

Referring toFIG. 1, respective remote controllers150are disposed in respective indoor spaces, and each of the remote controllers150manipulates operational information of the air conditioner140by communication with the indoor unit130disposed in an indoor space. The remote controller150and the indoor unit130perform communication by wires or wireless, and the remote controller150may be a wired remote control or wireless remote control.

Referring toFIG. 2, the remote controller150includes an input unit151, a display unit153, a database152, a communication module155, and a control unit154.

The communication module155of the remote controller150can transmit a control signal for controlling the operation of the air conditioner140or receive operational information of the air conditioner140through data communication with a communication module (not shown) provided in the indoor unit130.

The database152stores image data to be displayed on the display unit153to be described later, and stores operating conditions of the air conditioner140received via the communication module155. Also, changes in outdoor temperature detected through the outdoor temperature detecting unit136are stored, and the control unit154increases or decreases a desired temperature of the indoor unit130based on an increase or decrease in outdoor temperature detected in the outdoor temperature detecting unit136.

FIG. 3is a graph for explaining an operation of increasing or decreasing a temperature based on an increase or decrease in outdoor temperature in accordance with one embodiment of the present invention. Referring toFIG. 3, an outdoor temperature increases or decreases with the passage of time, and the control unit154increases or decreases a desired temperature in response to an increase or decrease in outdoor temperature. Here, the control unit154varies the desired temperature at a variable gradient smaller than the variable gradient per predetermined time of the outdoor temperature.

Referring toFIG. 3, as time passes from 0 to 1, the outdoor temperature rises at a variable gradient of a1. While the same time passes, the desired temperature rises at a variable gradient of a2. Here, the variable gradient of a2is smaller than the variable gradient of a1. In the event that the desired temperature is varied with the rise of the outdoor temperature, if the desired temperature is raised at a variable gradient same as or greater than the variable gradient of the outdoor temperature, the desired temperature of the room rises at a width same as or greater than the change of the outdoor temperature with the rise of the outdoor temperature. As the rise width of the desired temperature becomes greater, the rise width of the indoor temperature also become greater, thereby lowering the feeling of comfort of the user. Therefore, air conditioning sickness that may occur in the event of a significant diurnal range in temperature can be prevented by varying a desired temperature according to a change in outdoor temperature, and the room can be kept pleasant by varying a desired temperature at a variable gradient smaller than the variable gradient of the outdoor temperature.

Referring toFIG. 3, when the outdoor temperature falls at a variable gradient of b1while time passes from t2to t3, as well as when the outdoor temperature increases, the desired temperature falls at a variable gradient of b2which is smaller than b1, the effect of which is as described above.

FIG. 4is a graph for explaining an operation in which a desired temperature rises in accordance with one embodiment of the present invention.FIG. 5is a graph for explaining an operation in which a desired temperature falls in accordance with one embodiment of the present invention. Referring toFIG. 4, in an interval where the desired temperature varies with time, there exists a rising period, i.e., a period in which time passes from t4to t7, and the variable gradient at one segment of the rising period may be different from the variable gradient at other segments of the rising period. Concretely, as time passes from t3to t5, the desired temperature may rise at a variable gradient of c1. However, the desired temperature does not continuously rise at the same variable gradient, but may rise at a variable gradient of c2, which is smaller than c1, even in the same rising period, while time passes from t5to t6. Accordingly, it is not that the desired temperature as well rises at a constant variable gradient according to the variation of the outdoor temperature, but there may exist a segment where the desired temperature rises at a different variable gradient even in the same rising period. Thus, the control unit14can adjust the desired temperature so as to avoid the desired temperature from rising substantially. Consequently, the pleasantness of the room can be maintained within a predetermined range by varying the rising gradient of the desired temperature.

Referring toFIG. 5, in an interval where the outdoor temperature falls and the desired temperature varies with time, as well as when the desired temperature increases, a falling period exists, and the variable gradient at one segment of the falling period may be different from the variable gradient at other segments of the falling period. That is, in an interval where the desire temperature varies with time, a falling period, i.e., a period in which time passes from t4to t7, exists, and the desired temperature may fall at a falling gradient of d2, which is smaller than d1, even in the same falling period, while time passes from t9to t10. Consequently, the pleasantness of the room can be maintained within a predetermined range by varying the falling gradient of the desired temperature.

FIG. 6is a graph for explaining an operation in which a deviation temperature increases or decreases based on an increase or decrease in outdoor temperature in a cooling mode of an indoor unit130in accordance with another embodiment of the present invention.

Referring toFIG. 6, the control unit154calculates a deviation temperature having a predetermined deviation from an outdoor temperature detected in the outdoor temperature detecting unit136, and compares the deviation temperature and a desired temperature to set a new desired temperature. That is to say, in the event that a desired temperature is varied, the desired temperature is not calculated immediately with the variation of an outdoor temperature, but a deviation temperature is calculated, and then the calculated deviation temperature and the current desired temperature are compared to thus calculate a new desired temperature. Here, as the outdoor temperature varies, the control unit154varies the deviation between the outdoor temperature and the deviation temperature.

Referring toFIG. 6, if the indoor unit130performs a cooling operation, the outdoor temperature varies along a predetermined rising period A and falling period B. First, in the interval A in which the outdoor temperature rises, the control unit calculates a deviation temperature having a predetermined deviation d1and d2from the outdoor temperature. For example, if the current desired temperature is 25° C. and the outdoor temperature at a specific time of the interval A is 35° C. and 40° C., respectively, d1may be set to 5° C. and d2may be set to 8° C. In this case, the deviation temperature is 30° C. (35−5) and 32° C. (40−8), respectively. That is, with the rise of the outdoor temperature, the deviation is varied from d1(5° C.) to d2(8° C.), and the deviation temperature also increases from 30° C. to 32° C. In other words, even if the outdoor temperature rises, a deviation temperature having the same deviation as that of the outdoor temperature is not calculated, but the deviation is varied and then a deviation temperature is calculated.

The control unit154compares the calculated deviation temperature and the current desired temperature of 25° C., and sets the larger value as a new desired temperature. That is, if the desired temperature of 25° C. and the calculated temperature of 30° C. are compared with each other, the deviation temperature is the larger value, and hence the deviation temperature (30° C.) is set as a new desired temperature. Likewise, even when the newly calculated deviation temperature is 32° C. after the passage of time, the deviation temperature is the larger value, and hence the deviation temperature (32° C.) is set as a new desired temperature. The reason why the deviation temperature and the current desired temperature are compared with each other and the larger value is set as a new desired temperature is because in the event of the cooling mode of the indoor unit130, it is possible to prevent the desired temperature from being set too low, thus preventing the room from being too cold and resultantly preventing an increase of power consumption of the indoor unit.

Referring toFIG. 6, as the outdoor temperature rises, the deviation becomes larger. That is to say, in the interval A ofFIG. 6, d2becomes larger than d1with the rise of the outdoor temperature, and hence the rise width of the deviation temperature becomes smaller than the rise width of the outdoor temperature. Therefore, when setting a new desired temperature based on the deviation temperature, the new desired temperature can be maintained not to change substantially, thereby keeping the room pleasant.

Referring toFIG. 6, as the outdoor temperature falls, the deviation becomes smaller. That is to say, in the interval B ofFIG. 6, d4becomes smaller than d3with the fall of the outdoor temperature, and hence the fall width of the deviation temperature becomes smaller. Therefore, when setting a new desired temperature based on the deviation temperature, the new desired temperature can be maintained not to change substantially, thereby keeping the room pleasant.

FIG. 7is a graph for explaining an operation in which a deviation temperature increases or decreases based on an increase or decrease in outdoor temperature in a heating mode of an indoor unit in accordance with still another embodiment of the present invention.

Referring toFIG. 7, the control unit154calculates a deviation temperature having a predetermined deviation d5, d6, d7, and d8from an outdoor temperature detected in the outdoor temperature detecting unit136, and compares the deviation temperature and a desired temperature to set a new desired temperature, which is the same as in the above-described cooling operation.

In the heating operation as well, as the outdoor temperature varies, the control unit154varies the deviation between the outdoor temperature and the deviation temperature. Referring toFIG. 7, if the indoor unit130performs a heating operation, the outdoor temperature varies along a predetermined rising period C and falling period D. First, in the interval D in which the outdoor temperature rises, the control unit calculates a deviation temperature having a predetermined deviation d5and d6from the outdoor temperature. For example, if the current desired temperature is 20° C. and the outdoor temperature at a specific time of the interval C is 5° C. and 10° C., respectively, d5may be set to 10° C. and d6may be set to 8° C. In this case, the deviation temperature is 15° C. (5+10) and 18° C. (10+8), respectively. That is, with the rise of the outdoor temperature, the deviation is varied from d5(10° C.) to d6(8° C.), and the deviation temperature also increases from 15° C. to 18° C. In other words, even if the outdoor temperature rises, a deviation temperature having the same deviation as that of the outdoor temperature is not calculated, but the deviation is varied and then a deviation temperature is calculated.

The control unit154compares the calculated deviation temperature and the current desired temperature of 20° C., and sets the smaller value as a new desired temperature. That is, if the desired temperature of 20° C. and the calculated temperature of 15° C. are compared with each other, the deviation temperature is the smaller value, and hence the deviation temperature (15° C.) is set as a new desired temperature. Likewise, even when the newly calculated deviation temperature is 18° C. after the passage of time, the deviation temperature is the larger value than the desired temperature of 20° C., and hence the deviation temperature (18° C.) is set as a new desired temperature. The reason why the deviation temperature and the current desired temperature are compared with each other and the larger value is set as a new desired temperature is because in the event of the heating mode of the indoor unit130, it is possible to prevent the desired temperature from being set too high, thus preventing the room from being too hot and resultantly preventing an increase of power consumption of the indoor unit.

Referring toFIG. 7, as the outdoor temperature rises, the deviation becomes larger. That is to say, in the interval C ofFIG. 7, d6becomes smaller than d5with the rise of the outdoor temperature, and hence the rise width of the deviation temperature becomes smaller than the rise width of the outdoor temperature. Therefore, when setting a new desired temperature based on the deviation temperature, the new desired temperature can be maintained not to change substantially, thereby keeping the room pleasant.

Referring toFIG. 7, as the outdoor temperature falls, the deviation becomes larger. That is to say, in the interval D ofFIG. 7, d8becomes smaller than d7with the fall of the outdoor temperature, and hence the fall width of the deviation temperature becomes smaller. Therefore, when setting a new desired temperature based on the deviation temperature, the new desired temperature can be maintained not to change substantially, thereby keeping the room pleasant.

FIG. 8is a plan view showing an input unit and a display unit of the remote controller as shown inFIG. 1. Referring toFIG. 8, the user inputs a manipulation signal to manipulate operating conditions of the air conditioner through the input unit151. As stated above, the remote controller150may be a wired remote control or wireless remote control, and the input unit151may be a plurality of function keys provided at the wired remote control or wireless remote control.

The plurality of function keys operable by the user include a first function key151afor inputting a manipulation signal to enter a predetermined setting mode, second function keys151band151cfor indicating a predetermined direction, a third function key151dfor indicating set/clear, a fourth key151efor indicating exit, and sub function keys.

At least one of a desired temperature of the indoor unit130and an initial value of the deviation (d1and d2ofFIG. 5) is inputtable based on the manipulation signal inputted from the input unit151. Referring toFIG. 8, when the user presses the first function key51a,a temperatures setting mode for inputting a desired temperature or an initial value of the deviation is entered. InFIG. 8, the temperature setting mode for inputting a deviation is entered by the user's pressing the first function key151aon the display window153aof the display unit153. The user can select a desired temperature or an initial value of the deviation by pressing the second function keys151band151cto move the cursor up and down or left and right. When a desired temperature or an initial value of the deviation is selected, the user presses the third function key151dto complete setting.

The display unit153displays operational information of the air conditioner140. The display unit153displays operating conditions of the air conditioner140in various images. Concretely, the display window153aof the display unit153has an LCD panel structure, and the LCD panel structure is an FSTN (Film Super Twist Nematics). The LCD panel structure is divided into a TN LCD (Twsited Nematic LCD), a CTN (Complementary Tn), an STN (Super Twisted Nematic), a DSTN (Double Layer Super Twisted Nematic), an FSTN (Film Super Twist Nematics) and so forth depending on the physical properties of liquid crystal, the material of the panel, etc. The FSTN type uses a very thin polymerized film in place of a color compensating liquid crystal cell, and the display window153aof the display unit153of the present invention employs an LCD panel structure of FSTN type that can obtain a wide view angle and is suitable for thinning. An image represented on the display window153aof the display unit153is a set of dots which is represented as one dot on the coordinate plane. That is, display window153aof the display unit153is a dot type LCD which represents an image in the set of dots, and can represent image data as an image by lighting the dots with the use of the image data stored in the database152.

As a desired temperature varies, the display unit153displays the varied desired temperature. Unlike a variable gradient of an outdoor temperature or a variable value of a deviation temperature, a varied desired temperature is information in which the user is mainly interested, and information about a desired temperature varied in real time can be provided through the display unit153.

Meanwhile, each indoor unit130is provided with an indoor temperature sensor135for detecting an indoor temperature of the place where the indoor unit is placed, and the control unit154varies the indoor temperature detected in the indoor temperature sensor135within a predetermined upper limit and lower limit range. That is, even if a new desired temperature is set due to the variation of a desired temperature or the variation of a deviation temperature, the indoor temperature is varied within the predetermined upper limit and lower limit range. Thus, even on a day with a large diurnal range in temperature, the temperature of a room can be maintained within a given range, thereby keeping the room pleasant.

FIG. 9is a block diagram showing the configuration of an air conditioning system in accordance with another embodiment of the present invention. The following description will be focused on differences from the foregoing embodiment.

Referring toFIG. 9, the air conditioning system200includes an air conditioner240and a remote controller250. The air conditioner240includes a plurality of indoor units230and an outdoor unit220. The indoor units230and the outdoor unit220are communicatively connected to each other via a first network261. Also, the outdoor units220are communicative connected to each other via a second network262. RS-485 communication is performed over the first network261and RS-485 communication is performed over the second network262. However, the present invention is not limited to the above communication method. The remote controller250is communicatively connected to the air conditioners240via the second network262.

A control unit (not shown) of the remote controller250selects a representative indoor unit among the indoor units230, and varies a desired temperature of the representative indoor unit at a variable gradient smaller than the variable gradient per predetermined time of the outdoor temperature of the representative indoor unit. Based on the variation of the desired temperature of the representative indoor unit, desired temperatures of the other indoor units230are varied. That is, although all of the respective indoor units230may detect an outdoor temperature respectively, and varies the desired temperatures of the respective indoor units230independently, it may also be possible to vary the desired temperatures of the other indoor units230in the same way depending on the variation of the desired temperature of the representative indoor unit by selecting the representative indoor unit. The desired temperature of the representative indoor unit is a temperature commonly applied to the entire indoor units230, and is inputtable through an input unit (not shown) of the remote controller250.

In case of selecting a representative indoor unit, the control unit (not shown) is able to select a representative indoor unit based on the indoor unit addresses allocated to the plurality of indoor units230. In this case, although the control unit (not shown) may select a representative indoor unit commonly applied for all of the indoor units230, it may also be possible to select a representative indoor unit among the indoor units230currently in operation. Hereinafter, a method for selecting a representative indoor unit will be explained.

First, indoor unit addresses are respectively allocated to the plurality of indoor units230. This is because the remote controller250needs to recognize the respective indoor units230in order to perform data communication with the respective indoor units230. Since the indoor unit addresses have a different value, the remote controller250can perform communication with the indoor units230by using the indoor unit addresses.

In order to allocate an indoor unit address to each indoor unit230, generally, an installer or user can directly move to the places where each indoor unit230is installed, and set addresses by a remote control connected to the corresponding indoor unit230. However, this causes the installer or user's inconvenience of having to directly moving. Thus, for the indoor unit address of the present invention, the outdoor unit220provided with an automatic address setting function is used, thereby increasing user convenience.

FIG. 10is a block diagram showing the internal configuration of the outdoor unit as shown inFIG. 9. Referring toFIG. 10, the outdoor unit220includes an outdoor unit database223for storing address data of the indoor units230, a communication module224connected to the indoor units230for sending and receiving data, and an outdoor microcomputer221for automatically allocating indoor unit addresses to the indoor units230according to a request from the control unit (not shown). The outdoor unit database223stores the indoor unit addresses of the indoor units connected to the outdoor unit220, and stores an automatic address setting program for allocating the addresses of the indoor units230. The outdoor unit microcomputer122includes an automatic address setting unit222for allocating the addresses of the indoor units230connected to the outdoor unit220. The control unit (not shown) of the remote controller240transmits, to the outdoor unit220, a request signal for automatically allocating the addresses of the indoor units230. When the request signal is received, the automatic address setting unit222operates the automatic address setting program stored in the outdoor unit database223to allocate the address values for the respective indoor units230connected to the outdoor unit220. For example, if 16 indoor units230are connected to the outdoor unit220, the automatic address setting unit222sequentially allocates address values for the indoor units230in the order of higher values, like ‘indoor unit 1(IDU1)’, ‘indoor unit 2(IDU2)’, . . . ’indoor unit 16(IdU16)’. The outdoor unit microcomputer221stores address data of the indoor units230allocated through the automatic address setting unit222in the outdoor unit database223, and transmits them to the respective indoor units230. Moreover, the outdoor unit microcomputer221transmits the stored data of the respective indoor units to the remote controller250according to a request from the control unit (not shown) of the remote controller250, and the indoor unit address data is stored in the database (not shown) of the remote controller250.

After the indoor unit addresses are allocated to the respective indoor units230of the air conditioner240, the control unit (not shown) of the remote controller250selects a representative indoor unit among the indoor units230. The control unit (not shown) is able to select, as the representative indoor unit, an arbitrary one of all the indoor units230allocated with the indoor unit addresses. The arbitrary indoor unit may be an indoor unit having the smallest value of the indoor unit address or an indoor unit corresponding to the indoor unit address firstly registered in the database (not shown) of the remote controller according to the user's selection.

Meanwhile, the control unit (not shown) may select, as the representative indoor unit, an arbitrary one of the indoor units230in operation, among the indoor units230allocated with the indoor unit addresses. That is, if the representative indoor unit is selected among all the indoor units230allocated with the indoor unit addresses, the indoor unit currently being stopped in operation may be selected as the representative indoor unit. Hence, by selecting the representative indoor unit among the indoor units230currently in operation, the accuracy of variation of a desired temperature can be ensured. As described above, the arbitrary indoor unit may be an indoor unit having the smallest value of the indoor unit address or an indoor unit corresponding to the indoor unit address firstly registered in the database (not shown) of the remote controller according to the user's selection.

Although the control unit (not shown) may automatically select the representative indoor unit based on the indoor unit addresses, it is possible for the user to directly select an arbitrary one of all the indoor units230or of the indoor units230in operation as the representative indoor unit based on a manipulation signal inputted from the input unit (not shown) of the remote controller250.

Meanwhile, the control unit (not shown) can calculate the average value of the variable gradients per predetermined time of the outdoor temperature of the places where the indoor units230are installed, and vary the desired temperatures of the indoor units230at a variable gradient smaller than the average value of the variable gradients per predetermined time of the outdoor temperature. In other words, the average value of the variable gradients per predetermined time of the outdoor temperature of the places where the indoor units230are installed is calculated so that the desired temperatures of the indoor units230can be collectedly varied, rather than each indoor unit230's individually performing the control for varying a desired temperature. Here, the control unit (not shown) may calculate the average value of the variable gradients per predetermined time of the outdoor temperature of the places where all the indoor units230are installed, or calculate the average value of the variable gradients per predetermined time of the outdoor temperature of the places where the indoor units230in operation are installed.

Meanwhile, the outdoor unit120as shown inFIG. 1is provided with a compressor (not shown) capable of varying the capacity. Here, the compressor may be comprised of an inverter compressor so as to compress a different amount of refrigerant depending on a required air conditioning heat quantity.

As the outdoor temperature detected in the outdoor temperature detecting unit136varies, the control unit154varies the operation factor of the compressor according to a cooling mode or heating mode when varying a desired temperature. Here, the compressor is an inverter compressor, and if the operation factor of the compressor is varied, the control unit154adjusts the operating frequency of the inverter compressor. Concretely, the control unit154varies the operating frequency for controlling the compressor in order to vary the capacity of the inverter compressor. The inverter compressor can quickly create a user-desired air conditioning environment because the number of rotations can be varied, and can eliminate noise generated upon switching on/off the compressor because a require amount of refrigerant can be compressed without the on/off control of the compressor. By the operating frequency for controlling the compressor, the number of rotations of the inverter compressor, the compression amount of refrigerant, and the air conditioning heat quantity of the air conditioner can be adjusted. As a result, the operation states of the indoor units130can be controlled by the control unit154by varying the operating frequency of the inverter compressor.

In the cooling mode, if a new desired temperature is lower than the previous desired temperature, because the load is increased, the control unit154increases the operation factor of the compressor, and if a new desired temperature is higher than the previous desired temperature, because the load is decreased, the control unit154decreases the operation factor of the compressor. Likewise, in the heating mode, if a new desired temperature is lower than the previous desired temperature, because the load is decreased, the control unit154decreases the operation factor of the compressor, and if a new desired temperature is higher than the previous desired temperature, because the load is increased, the control unit154increases the operation factor of the compressor.

Although the present invention has been described with reference to the embodiments shown in the drawings, these are merely illustrative, and those skilled in the art will understand that various modifications and equivalent other embodiments of the present invention are possible. Consequently, the true technical protective scope of the present invention must be determined based on the technical spirit of the appended claims.