Air conditioner

Abstract

To disclose one example of an air conditioner that can suppress deterioration in efficiency of the air conditioner and instability of a room temperature by suppressing frequent repetition of thermo-on and thermo-off.SOLUTION: In an air conditioner 1, when a thermo-off function is executed more than a predetermined number of times until a predetermined period of time has elapsed from the time at which the thermo-off function is executed, after an addition value change function is executed and a startup temperature Tu is changed to a changed startup temperature Tu, a thermo-on function or the thermo-off function is executed. Consequently, since it is possible to prevent the thermo-on function and the thermo-off function from being repeated frequently, it is possible to prevent the efficiency of the air conditioner from deteriorating and a room temperature from becoming unstable. The additional value change function is a function to make the startup temperature Tu higher than a current temperature.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to an air conditioner for indoor use.

Background Art

[0002] When the air conditioner operates in a state where the heat load is small, a state in which thermo-on and thermo-off are frequently repeated is likely to occur. In this state, there is a possibility that the efficiency of the air conditioner decreases and the room temperature becomes unstable.

[0003] In contrast, for example, in Patent Document 1, when the thermo-off state is reached and the outside air temperature or humidity satisfies a condition of being equal to or lower than a predetermined threshold value, a thermo-off time extension mode is executed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In view of the above points, the present disclosure discloses an example of an air conditioner capable of suppressing a decrease in the efficiency of the air conditioner and instability of the room temperature by suppressing frequent repetition of thermo-on and thermo-off.

Means for Solving the Problems

[0006] The air conditioner preferably includes at least one of the following components. That is, the component includes a heat exchanger (5) that cools the air supplied to the room, a temperature sensor (S1) that detects the temperature of the air before being cooled by the heat exchanger or the temperature of the air after being cooled by the heat exchanger, and a control unit (6) that controls the cooling capacity generated by the heat exchanger. The control unit (6) can execute a normal control function, a thermo-off function, a thermo-on function, and an added value change function.

[0007] The normal control function is a function that controls the cooling capacity generated by the heat exchanger (5) using the detected temperature (Ti) of the temperature sensor (S1). The thermo-off function is a function that stops the generation of cooling capacity when at least a condition (hereinafter referred to as the thermo-off condition) including that the detected temperature (Ti) is equal to or lower than the thermo-off temperature (Tc) is satisfied.

[0008] The thermo-on function is a function that generates cooling capacity when the detected temperature (Ti) exceeds the activation temperature (Tu), where the activation temperature (Tu) is the temperature obtained by adding a value of 0 or more (hereinafter referred to as the added value (α)) to the thermo-off temperature (Tc).

[0009] The added value change function is a function that increases the added value (α) to be larger than the current added value (α) when the thermo-off function or the thermo-on function is executed a predetermined number of times or more before a predetermined time elapses from when the thermo-off function is executed.

[0010] Thereby, it is possible to suppress the frequent repetition of thermo-on and thermo-off, so that it is possible to suppress a decrease in the efficiency of the air conditioner and instability of the room temperature.

[0011] Incidentally, the reference numerals in the above parentheses are examples showing the correspondence with the specific configurations and the like described in the embodiments described later, and the present disclosure is not limited to the specific configurations and the like indicated by the reference numerals in the above parentheses.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Mode for Carrying Out the Invention

[0013] The following "Embodiment of the Invention" shows an example of embodiments belonging to the technical scope of the present disclosure. That is, the invention specific matters described in the claims are not limited to the specific configurations and structures shown in the following embodiments.

[0014] At least the members or parts described with reference numerals are provided with at least one, unless otherwise stated such as "one". That is, when there is no statement such as "one", two or more of the members may be provided. The air conditioner shown in the present disclosure includes at least the components described with reference numerals and the structural elements shown in the drawings.

[0015] (First Embodiment) <1. Outline of the air conditioner> In the present embodiment, an example of the air conditioner according to the present disclosure is applied to an air conditioner that air-conditions a server room such as a data center or a communication machine room. As shown in FIG. 1, the air conditioner 1 is a so-called "package air conditioner" composed of a vapor compression refrigerator.

[0016] The air conditioner 1 generates cooling or heating (cooling in the present embodiment) for air-conditioning the server room. The air conditioner 1 includes a compressor 2, a condenser 3, an expander 4, an evaporator 5, a first blower 3A and a second blower 5A, a control unit 6, a first temperature sensor S1, a second temperature sensor S2, and the like.

[0017] The compressor 2 compresses the low-pressure gaseous refrigerant and supplies it to the condenser 3. The compressor 2 is driven by an electric motor (not shown). The electric motor is driven by an inverter type drive circuit (not shown). The operation of the drive circuit is controlled by the control unit 6.

[0018] That is, the drive circuit supplies a drive current to the electric motor and can change the frequency of the drive current (hereinafter referred to as the drive frequency). The drive circuit supplies a drive current with a drive frequency corresponding to the command frequency from the control unit 6 to the electric motor. That is, the operation of the compressor 2 is controlled by the control unit 6 via the drive circuit.

[0019] The condenser 3 is a high-pressure side heat exchanger that cools the high-pressure refrigerant compressed by the compressor 2. In the condenser 3, the gaseous refrigerant is cooled and liquefied (condensed). The decompressor 4 decompresses and expands the high-pressure refrigerant flowing out from the condenser 3 and supplies it to the evaporator 5.

[0020] The evaporator 5 evaporates the liquid-phase low-pressure refrigerant to generate cold heat. The first blower 3A blows cooling air to the condenser 3. The second blower 5A generates an air flow that passes through the evaporator 5 and is supplied into the server room.

[0021] The control unit 6 controls at least the compressor 2 and the second blower 5A. Detection signals from the first temperature sensor S1 and the second temperature sensor S2 are input to the control unit 6. The control unit 6 controls the compressor 2 and the second blower 5A using the detection signals.

[0022] The first temperature sensor S1 detects the temperature of the air before being cooled by the evaporator 5. The second temperature sensor S2 detects the temperature of the air after being cooled by the evaporator 5. Hereinafter, the detected temperature of the first temperature sensor S1 is referred to as the suction temperature Ti. The detected temperature of the second temperature sensor S2 is referred to as the blow-out temperature To.

[0023] Note that the control unit 6 is configured by a microcomputer having a CPU, ROM, RAM, etc. Then, by executing software stored in a non-volatile storage unit such as ROM by the CPU, the following controls and functions are realized.

[0024] <2. Control operation of the air conditioner> <2.1 Outline of compressor control> The control unit 6 can control the compressor 2 with a suction priority control function (hereinafter also referred to as a normal control function), a thermo-off function, or a thermo-on function. The suction priority control function controls the magnitude of the refrigerating capacity generated in the evaporator 5.

[0025] The thermo-off function is a control for stopping the compressor 2. The thermo-on function is a control for starting the compressor 2 that has been stopped by the thermo-off function. After the compressor 2 is started by the thermo-on function, the suction priority control function is executed.

[0026] <Suction priority control function> In the suction priority control function, the control unit 6 controls the rotational speed of the compressor 2 so that the suction temperature Ti becomes a preset temperature (hereinafter referred to as the set temperature Ts). Specifically, when the suction temperature is higher than the set temperature Ts, the control unit 6 increases the rotational speed of the compressor 2. When the suction temperature is lower than the set temperature Ts, the control unit 6 decreases the rotational speed of the compressor 2.

[0027] <Thermo-off function> In the thermo-off function, when the state where a predetermined condition (hereinafter referred to as a stop condition) is satisfied exceeds a predetermined time, that is, when the thermo-off condition is satisfied, the control unit 6 stops the compressor 2 to stop the generation of cold heat. The stop condition is a necessary condition for the thermo-off function to be executed.

[0028] The stop condition according to this embodiment refers to a temperature condition in which the suction temperature Ti is equal to or lower than a predetermined temperature (hereinafter referred to as the thermo-off temperature Tc), and the rotational speed of the compressor 2 is equal to or lower than a predetermined rotational speed (hereinafter referred to as the lower limit rotational speed). The thermo-off temperature Tc is the same temperature as the set temperature Ts or a temperature lower than the set temperature Ts.

[0029] The control unit 6 according to this embodiment grasps the "rotation speed of the compressor 2" based on the driving frequency. That is, when the suction temperature Ti drops below the thermo-off temperature Tc and the driving frequency becomes equal to or lower than the frequency corresponding to the lower limit rotation speed (hereinafter referred to as the minimum frequency) and this state continues for a predetermined time, the control unit 6 stops the compressor 2.

[0030] <Thermo-on function> The thermo-on function is a function that starts the compressor 2 to generate cooling when the suction temperature Ti exceeds the start temperature Tu. The start temperature Tu is the temperature obtained by adding a value of 0 or more (hereinafter referred to as the addition value α) to the thermo-off temperature Tc.

[0031] <Addition value change function> The addition value change function is a function that increases the addition value α to be larger than the current addition value α when the thermo-off function or the thermo-on function (in this embodiment, the thermo-off function) is executed a predetermined number of times or more within a predetermined time (hereinafter referred to as "within the predetermined time") from when the thermo-off function is executed.

[0032] Note that the current addition value α is, for example, a value determined in advance as an initial value. Hereinafter, the start temperature Tu when the initial value is used as the addition value α is referred to as the initial start temperature Tu. That is, in this embodiment, two types of start temperatures Tu are used: the initial start temperature Tu and the start temperature Tu after the addition value change function is executed (hereinafter referred to as the changed start temperature Tu).

[0033] <Start temperature return function> The start temperature return function is a function that returns the changed start temperature Tu to the start temperature Tu before the change after executing the thermo-on function at the changed start temperature Tu. Note that the addition value change function and the start temperature return function are functions that are executed independently and in parallel with the thermo-off function and the thermo-on function.

[0034] Therefore, until a predetermined time elapses after the thermo-off function is executed, when the suction temperature Ti exceeds the initial startup temperature Tu, the thermo-on function is executed, and when the thermo-off condition is satisfied, the thermo-off function is executed.

[0035] And, if the thermo-off function is executed more than a predetermined number of times until a predetermined time elapses after the thermo-off function is executed, the addition value change function is executed, and after the startup temperature Tu is changed to the changed startup temperature Tu, the thermo-on function or the thermo-off function is executed.

[0036] At this time, when the thermo-on function is executed at the changed startup temperature Tu and the compressor 2 is started, the startup temperature Tu is changed from the changed startup temperature Tu to the initial startup temperature Tu. After that, again, when the suction temperature Ti exceeds the initial startup temperature Tu, the thermo-on function is executed, and when the thermo-off condition is satisfied, the thermo-off function is executed.

[0037] Specifically, as shown in FIG. 2, the addition value change function and the startup temperature return function are executed.

[0038] That is, when the air conditioner 1 is started, the control unit 6 determines whether or not a predetermined time has elapsed after the execution of the thermo-off function (S1). If a predetermined time has elapsed after the execution of the thermo-off function (S1: YES), the control unit 6 determines whether or not the number of executions of the thermo-off function is equal to or greater than a predetermined number (S3).

[0039] If the number of executions of the thermo-off function is equal to or greater than a predetermined number (S3: YES), the control unit 6 executes the addition value change function (S5), and then determines whether or not the thermo-on function is executed at the changed startup temperature Tu (S7).

[0040] If the thermo-on function is executed at the changed startup temperature Tu (S7: YES), the control unit 6 executes the startup temperature return function (S9), and then executes S1 again. Note that these controls are executed independently and in parallel with the suction priority control function, the thermo-off function, and the thermo-on function as described above.

[0041] <3. Features of the air conditioner according to this embodiment> In the air conditioner 1 according to this embodiment, when the thermo-off function is executed more than a predetermined number of times until a predetermined time elapses after the thermo-off function is executed, the addition value change function is executed and the start temperature Tu is changed to the changed start temperature Tu, and then the thermo-on function or the thermo-off function is executed.

[0042] As a result, it is possible to suppress the frequent repetition of the thermo-on function and the thermo-off function, so that it is possible to suppress a decrease in the efficiency of the air conditioner and instability of the room temperature.

[0043] (Other embodiments) In the above-described embodiment, an example of the air conditioner according to the present disclosure was applied to an air conditioner that conditions the server room. However, the present disclosure is not limited to this. That is, the present disclosure is applicable to, for example, air conditioning of a room other than the server room.

[0044] The heat exchanger of the air conditioner 1 according to the above-described embodiment was a low-pressure side heat exchanger of a vapor compression refrigerator, that is, an evaporator. However, the present disclosure is not limited to this. That is, the present disclosure may be, for example, an air conditioner that circulates chilled water cooled by an evaporator through the heat exchanger to generate cold heat.

[0045] The air conditioner according to the above-described embodiment was a cooling device that uses cold heat. However, the present disclosure is not limited to this. That is, the present disclosure is also applicable to, for example, a heating device that uses warm heat. In this case, the start temperature Tu is a temperature obtained by subtracting the addition value α from the thermo-off temperature Tc.

[0046] The normal control function according to the above-described embodiment was a suction priority control function. However, the present disclosure is not limited thereto. That is, the present disclosure may be configured such that the normal control function is executed by a blow-out priority control function, for example. In the blow-out priority control function, cooling / heating is controlled so that the blow-out temperature To becomes the set temperature, and the second blower 5A is subjected to increase / decrease control linked to the rotational speed of the compressor 2.

[0047] Furthermore, the present disclosure only needs to conform to the gist of the disclosure described in the above-described embodiment, and is not limited to the above-described embodiment. Therefore, a configuration in which at least two of the above-described multiple embodiments are combined, or a configuration in which any one of the configuration components shown in the drawings or the configuration components described with reference numerals in the above-described embodiment is abolished may also be acceptable.

Explanation of Reference Numerals

[0048] 1... Air conditioner 2... Compressor 3... Condenser 3A... First blower 4... Throttle 5... Evaporator 5A... Second blower 6... Control unit S1... First temperature (suction temperature) sensor S2... Second temperature (blow-out temperature) sensor

Claims

1. a heat exchanger that cools the air supplied indoors; a temperature sensor that detects the temperature of the air before being cooled by the heat exchanger or the temperature of the air after being cooled by the heat exchanger; a control unit that controls the cooling capacity generated by the heat exchanger, wherein the control unit has a normal control function of controlling the cooling capacity generated by the heat exchanger using the detected temperature of the temperature sensor, a thermo-off function of stopping the generation of cooling capacity when a condition (hereinafter referred to as the thermo-off condition) including at least that the detected temperature is equal to or lower than a predetermined temperature (hereinafter referred to as the thermo-off temperature) is satisfied, a thermo-on function of generating cooling capacity when the detected temperature exceeds the activation temperature, where the activation temperature is the temperature obtained by adding a value of 0 or more (hereinafter referred to as the addition value) to the thermo-off temperature, and an addition value change function of making the addition value larger than the current addition value when the thermo-off function or the thermo-on function is executed a predetermined number of times or more before a predetermined time has elapsed since the thermo-off function was executed, when the activation temperature after the addition value change function is executed is defined as the changed activation temperature, the control unit is an air conditioner capable of executing an activation temperature return function of returning the changed activation temperature to the activation temperature before the change after executing the thermo-on function at the changed activation temperature.

2. The heat exchanger is a heat exchanger that cools air using the cooling capacity generated by a vapor compression refrigerator, wherein the thermo-off function is a control for stopping the compressor when the condition that the detected temperature is equal to or lower than the thermo-off temperature, the rotational speed of the compressor is equal to or lower than a predetermined rotational speed, and the state where the stop condition is satisfied continues for a predetermined time or more is satisfied, and the thermo-off condition is considered to be satisfied. The air conditioner according to claim 1.

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