Air conditioning device

Abstract

To provide one example of an air conditioner capable of inhibiting a large decrease in the air conditioning capacity because of excessive rise of a heat load temperature.SOLUTION: When a suction temperature is higher than a predetermined temperature, an air conditioner 10 performs a bypass function to increase the amount of introduced airflow to be returned upstream of an evaporator 5 compared to the case where the suction temperature is equal to or lower than the predetermined temperature. This can inhibit a heat load (cooling load) of the evaporator 5 from becoming excessively large and exceeding the capacity of the air conditioner 10. Accordingly, it is possible to inhibit a large decrease in the air conditioning capacity because of, e.g., stoppage of the air conditioner 10 due to activation of a safety function or the like of the air conditioner 10.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an air conditioner that has a heat exchanger that cools air drawn from inside a room and supplies the cooled air to the room. [Background technology]

[0002] For example, Patent Document 1 describes an air conditioner equipped with a bypass flow path. The bypass flow path is a flow path that takes in a portion of air whose temperature has been adjusted by a cooling coil and a reheater, and returns the taken-in air to the vicinity of the air intake port. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-45770 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure discloses an example of an air conditioning device capable of suppressing a significant decrease in air conditioning capacity due to an excessive rise in heat load temperature. The heat load temperature refers to the temperature of air before being cooled by a heat exchanger or the temperature of air after being cooled by the heat exchanger. [Means for solving the problem]

[0005] An air conditioner having a heat exchanger (5) that cools air drawn from inside a room and supplies the cooled air to the room desirably has at least one of the following configuration requirements, for example.

[0006] In other words, the constituent elements include temperature sensors (S1, S2) that detect the temperature of the air before it is cooled by the heat exchanger (5) or the air after it has been cooled by the heat exchanger (5), a circulation device (8) that introduces at least a portion of the air cooled by the heat exchanger (5) (hereinafter referred to as cold air) into the upstream air flow of the heat exchanger (5), and an electric fan (6A) that blows the cold air toward the room, and when the temperature detected by the temperature sensors (S1, S2) (hereinafter referred to as the heat load temperature) is higher than a predetermined temperature (hereinafter referred to as the introduction start temperature), the circulation device (8) has the function of increasing the amount of cold air introduced upstream (hereinafter referred to as the introduction air volume) compared to when the heat load temperature is equal to or lower than the introduction start temperature.

[0007] This can prevent the heat load (cooling load) of the heat exchanger (5) from becoming excessively large and exceeding the capacity of the air conditioner, and can also prevent a significant drop in air conditioning capacity due to a safety function or the like of the air conditioner being activated, causing the air conditioner to stop.

[0008] The air conditioner may have the following configuration.

[0009] In other words, it is desirable for the reflux device (8) to be able to perform the above function when the state in which the heat load temperature is higher than the introduction start temperature continues for a predetermined period of time or longer.

[0010] It is desirable that the reflux device (8) has a function of increasing the introduced air volume when the air volume of the electric fan (6A) is greater than a predetermined air volume (hereinafter referred to as the introduction start air volume) compared with when the air volume is equal to or less than the introduction start air volume.

[0011] This can prevent the heat load (cooling load) of the heat exchanger (5) from becoming excessively large and exceeding the capacity of the air conditioner, and therefore can prevent a significant decrease in the air conditioning capacity.

[0012] In addition, it is desirable that the heat exchanger (5) is configured as a low-pressure side heat exchanger of a vapor compression type refrigerator having a compressor (2), and that the reflux device (8) has a function of increasing the amount of introduced air when the rotation speed of the compressor (2) is higher than a predetermined rotation speed (hereinafter referred to as the introduction start rotation speed) compared to when the rotation speed is equal to or lower than the introduction start rotation speed.

[0013] This can prevent the heat load (cooling load) of the heat exchanger (5) from becoming excessively large and exceeding the capacity of the air conditioner, and therefore can prevent a significant decrease in the air conditioning capacity.

[0014] It is also desirable that the radiator (3) which radiates heat absorbed in the heat exchanger (5) to the outside of the room is configured as a high-pressure side heat exchanger of a vapor compression refrigerator, and that the radiator (3) includes an outside air temperature sensor (S3) which detects an ambient temperature of the radiator (3), and that the reflux device (8) has a function of reducing the amount of introduced air when the temperature detected by the outside air temperature sensor (S3) (hereinafter referred to as the outside air temperature) is higher than a predetermined temperature (hereinafter referred to as the suppression start temperature) compared to when the outside air temperature is equal to or lower than the suppression start temperature.

[0015] When the outside air temperature is higher than the suppression start temperature, it is desirable to execute droop control to suppress an increase in the refrigerant pressure in the radiator (3).

[0016] Incidentally, the symbols in the above parentheses are examples showing the corresponding relationship with the specific configurations etc. described in the embodiments described below, and the present disclosure is not limited to the specific configurations etc. shown by the symbols in the above parentheses. [Brief description of the drawings]

[0017] [Figure 1] 1 is a diagram showing an air conditioner according to a first embodiment. [Diagram 2] 1 is a diagram showing a vapor compression refrigeration machine according to a first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The following "embodiment of the invention" shows an example of an embodiment that falls within the technical scope of the present disclosure. In other words, the invention-specific matters described in the claims are not limited to the specific configurations and structures shown in the following embodiment.

[0019] At least one of each of the components or parts described with a reference symbol is provided, unless otherwise specified by "one". In other words, unless otherwise specified by "one", two or more of the components may be provided. The air conditioner disclosed in this disclosure includes at least the components or parts described with a reference symbol, as well as the structural parts shown in the drawings.

[0020] (First embodiment) <1. Overview of air conditioning equipment, etc.> In this embodiment, the present disclosure is applied to an air conditioning device and an air conditioning system that provide air conditioning in a communication equipment room, a server room, etc. (hereinafter, referred to as a server room.) The air conditioning system is a system that includes a plurality of air conditioning devices and provides air conditioning in one server room using these plurality of air conditioning devices.

[0021] At least one rack R is installed in the server room SR as shown in Fig. 1. At least one information and communication technology device (hereinafter, referred to as ICT device) and the like are installed in the rack R.

[0022] The air conditioners 10 suck air from within the server room SR, cool the sucked air, and then supply the cooled air (hereinafter referred to as "cold air") into the server room SR.

[0023] The server room according to this embodiment is separated into a cold aisle (a space for supplying cold air) and a hot aisle (a space for exhausting hot air). The cold aisle is a space for distributing and supplying cold air to each ICT device.

[0024] The hot aisle is a space where air whose temperature has risen after cooling each ICT device gathers. The air conditioner 10 draws air from the server room SR through the hot aisle. The cold air is supplied to the cold aisle via a cold air duct provided under the floor of the server room SR.

[0025] <2. Air conditioner configuration> All of the air conditioners 10 according to this embodiment have the same configuration. Each air conditioner 10 is configured with a vapor compression refrigerator 1, for example, as shown in Fig. 2. The vapor compression refrigerator 1 has at least a compressor 2, a radiator 3, a pressure reducer 4, an evaporator 5, and an electric fan 6.

[0026] The compressor 2 is an electric compressor that compresses the low-pressure gas-phase refrigerant flowing out from the evaporator 5. The radiator 3 cools the high-pressure refrigerant discharged from the compressor 2 and whose temperature has increased. In other words, the radiator 3 radiates heat absorbed by the evaporator 5 to the outside.

[0027] The pressure reducer 4 reduces the pressure of the refrigerant flowing out from the radiator 3. The pressure reducer 4 according to this embodiment is configured with a thermostatic expansion valve. The thermostatic expansion valve automatically adjusts the opening degree (degree of pressure reduction) so that the degree of superheat of the refrigerant at the outlet side of the evaporator 5 becomes a predetermined value.

[0028] The evaporator 5 generates a refrigeration capacity, that is, cold heat, by evaporating the liquid-phase refrigerant decompressed by the pressure reducer 4. Specifically, the evaporator 5 exchanges heat between the air sucked from the server room SR and the refrigerant, and generates the cold air.

[0029] The electric fan 6 is a blower that draws in air from the server room SR and supplies it to the evaporator 5, and also blows the air cooled by the evaporator 5, i.e., cool air, into the server room SR. The type of the electric fan 6 is not important.

[0030] 1, the evaporator 5 and the electric fan 6 are housed in a single casing to form an indoor unit 7. The indoor unit 7 has an intake port 7A at an upper portion and an exhaust port 7B at a lower portion.

[0031] That is, the air in the server room SR is drawn into the indoor unit 7 through the intake port 7A. The cool air generated in the indoor unit 7 is supplied to the server room SR through the exhaust port 7B. The indoor unit 7 is provided with a bypass passage 8A and a damper 8B.

[0032] The bypass passage 8A is an air passage for introducing at least a part of the air that has passed through the evaporator 5 to the suction side of the evaporator 5, that is, to the upstream side of the air flow of the evaporator 5. In other words, the bypass passage 8A is an air passage connecting the front and rear of the evaporator 5.

[0033] The damper 8B is an intake air volume regulator for adjusting the amount of cold air (hereinafter referred to as intake air volume) flowing through the bypass passage 8A. The bypass passage 8A, the damper 8B, and the control device 9 (see FIG. 2) constitute a reflux device 8 that introduces cold air into the upstream side of the air flow of the evaporator 5.

[0034] 2, the air conditioner 10 also includes a control device 9, a suction temperature sensor S1, a discharge temperature sensor S2, and an outside air temperature sensor S3. The control device 9 controls the operation of the compressor 2, the electric fan 6, the damper 8B, and the like.

[0035] The detection values ​​of the sensors S1 to S3 are input to the control device 9. The suction temperature sensor S1 detects the air temperature before heat exchange in the evaporator 5. The discharge temperature sensor S2 detects the air temperature after heat exchange in the evaporator 5. The outside air temperature sensor S3 detects the ambient temperature of the radiator 3.

[0036] <2.1 Normal control of compressor and electric fan> The control device 9 controls the rotation speed of the compressor 2 via the drive unit 2A. The drive unit 2A is an inverter type drive circuit, and outputs a current for driving the compressor 2 (hereinafter, referred to as a drive current).

[0037] The control device 9 instructs the frequency of the drive current (hereinafter, referred to as the drive frequency) to the drive unit 2A. Therefore, the compressor 2 is driven to rotate at a rotation speed corresponding to the drive frequency instructed by the control device 9.

[0038] Then, the control device 9 controls the drive frequency by PID control or the like so that the temperature detected by the suction temperature sensor S1 (hereinafter referred to as the suction temperature) becomes a preset temperature (hereinafter referred to as the set temperature).

[0039] Specifically, when the suction temperature is higher than the set temperature, the controller 9 increases the drive frequency to increase the refrigeration capacity generated by the evaporator 5. When the suction temperature is lower than the set temperature, the controller 9 decreases the drive frequency to decrease the refrigeration capacity generated by the evaporator 5.

[0040] In addition, the control device 9 adjusts the airflow of the electric fan 6, that is, the value of the current supplied to the electric fan 6, so that the difference between the temperature detected by the blowing temperature sensor S2 (hereinafter referred to as the blowing temperature) and the suction temperature becomes a predetermined temperature difference.

[0041] <2.2 Control of the return flow device (damper)> <Bypass function> The reflux device 8, that is, the control device 9, can execute a bypass function. The bypass function is a function that increases the amount of cool air flowing through the bypass passage 8A (hereinafter referred to as the amount of introduced air) when at least one of the following multiple requirements (all of the requirements in this embodiment) is met (hereinafter referred to as the "time when the requirement is met") compared to before the requirement is met.

[0042] First requirement: The suction temperature is higher than a predetermined temperature (hereinafter referred to as the introduction start temperature).

[0043] Second requirement: The first requirement must continue for a predetermined period of time or longer.

[0044] Third requirement: The airflow rate of the electric fan 6A is greater than a predetermined airflow rate.

[0045] Fourth requirement: The rotation speed of the compressor 2 is greater than a predetermined rotation speed.

[0046] In this embodiment, when the requirements are not met, the damper 8B is closed. Therefore, the amount of introduced air when the requirements are not met is approximately 0. When the requirements are met, the damper 8B is opened and cool air flows through the bypass passage 8A.

[0047] In this embodiment, the condition not being satisfied refers to a condition where at least one of the first to fourth requirements is not satisfied. Therefore, if the condition is satisfied when at least one of the first to fourth requirements is satisfied, the condition is not satisfied when that one requirement is not satisfied.

[0048] The control device 9 according to the present embodiment uses the drive frequency to grasp the rotation speed of the compressor 2. That is, when the drive frequency is higher than a predetermined frequency, the control device 9 determines that the rotation speed of the compressor 2 is higher than the predetermined rotation speed.

[0049] Then, after starting the bypass function, the control device 9 stops the bypass function when the suction temperature becomes equal to or lower than the introduction start temperature. Also, when the duration of the bypass function execution reaches or exceeds a predetermined time, the control device 9 increases the rotation speed of the electric fan 6 of the other air conditioner 10.

[0050] In other words, when the duration of execution of the bypass function reaches or exceeds a predetermined time, the control device 9 of the air conditioner 10 that is executing the bypass function issues a command to increase the airflow volume to the control device 9 of the air conditioner that is not executing the bypass function.

[0051] <Bypass suppression function> The control device 9 can execute a bypass suppression function. The bypass suppression function is a function that reduces the amount of introduced airflow when the temperature detected by the outside air temperature sensor S3 (hereinafter referred to as the outside air temperature) is higher than a predetermined temperature (hereinafter referred to as the suppression start temperature) compared to when the outside air temperature is equal to or lower than the suppression start temperature.

[0052] Specifically, when the outside air temperature becomes higher than the suppression start temperature, the control device 9 performs control such as reducing the current amount of introduced air or closing the damper 8B to stop the bypass function and reducing the rotation speed of the compressor 2 (also called droop control).

[0053] In addition, when the outside air temperature drops below the suppression start temperature, the control device 9 stops the droop control, controls the compressor 2 using normal control, and determines whether the requirements for executing the bypass function are met.

[0054] 3. Features of the Air Conditioner and Air Conditioning System According to the Present Embodiment In the air conditioner 10 according to this embodiment, when the suction temperature is higher than the introduction start temperature, a bypass function is executed to increase the amount of introduced air compared to when the suction temperature is equal to or lower than the introduction start temperature.

[0055] This can prevent the heat load (cooling load) of the evaporator 5 from becoming excessively large and exceeding the capacity of the air conditioner 10. In turn, it can prevent a significant drop in air conditioning capacity due to a safety function or the like of the air conditioner 10 being activated, causing the air conditioner 10 to stop.

[0056] When the airflow rate of electric fan 6A is equal to or lower than a predetermined airflow rate (referred to as the introduction start airflow rate), air conditioner 10 increases the introduction airflow rate compared to when the airflow rate is equal to or lower than the introduction start airflow rate.

[0057] This can prevent the heat load (cooling load) of the evaporator 5 from becoming excessively large and exceeding the capacity of the air conditioner, and therefore can prevent a significant decrease in the air conditioning capacity.

[0058] When the rotation speed of the compressor 2 is higher than a predetermined rotation speed (hereinafter referred to as the introduction start rotation speed), the air conditioner 10 increases the amount of introduced air compared to when the rotation speed is equal to or lower than the introduction start rotation speed.

[0059] This can prevent the heat load (cooling load) of the evaporator 5 from becoming excessively large and exceeding the capacity of the air conditioner, and therefore can prevent a significant decrease in the air conditioning capacity.

[0060] When the outside air temperature becomes higher than the suppression start temperature, the air conditioner 10 reduces the amount of introduced air from the current amount, or closes the damper 8B to stop the bypass function and executes drooping control.

[0061] This can prevent the heat load of the air conditioner 10 from becoming excessively large, which can prevent the high-pressure side pressure, i.e., the refrigerant pressure in the radiator 3, from rising excessively. Furthermore, it can prevent a large decrease in air conditioning capacity due to a safety function or the like being activated due to an increase in the high-pressure side pressure, which can cause the air conditioner 10 to stop.

[0062] In the air conditioning system according to this embodiment, when the duration of the bypass function execution reaches or exceeds a predetermined time, the control device 9 of the air conditioner 10 executing the bypass function issues a command to increase the airflow to the control device 9 of the air conditioner not executing the bypass function. This can prevent the room temperature in the server room SR from rising excessively.

[0063] (Other embodiments) The control device 9 according to the embodiment described above stops the bypass function when the suction temperature becomes equal to or lower than the introduction start temperature after the bypass function starts to be executed. However, the present disclosure is not limited to this. That is, the present disclosure may be configured such that the bypass function stops when the requirements are not met, that is, when any of the first to fourth requirements is not met.

[0064] In the above embodiment, the control device 9 of the air conditioner 10 executing the bypass function issues a command to increase the airflow rate to the control device 9 of the air conditioner not executing the bypass function when the duration of execution of the bypass function reaches or exceeds a predetermined time. However, the present disclosure is not limited to this.

[0065] In other words, the disclosure may be configured, for example, to provide a monitoring device that performs integrated monitoring of multiple air conditioning devices 10, and to execute or stop the bypass function, and to control the airflow volume of air conditioning devices that are not executing the bypass function, based on the commands of the monitoring device.

[0066] In the droop control according to the embodiment described above, the rotation speed of the compressor 2 is reduced to suppress an excessive rise in the high-pressure side pressure, i.e., the refrigerant pressure in the radiator 3. However, the present disclosure is not limited to this. That is, the present disclosure may, for example, increase the throttle opening of the pressure reducer 4, or increase the rotation speed of the electric fan that blows cooling air to the radiator 3 to increase the blowing amount.

[0067] In the above embodiment, the bypass function is executed when all of the first to fourth requirements are met. However, the present disclosure is not limited to this. That is, the present disclosure may be configured such that the bypass function is executed when at least one of the first to fourth requirements is met, for example.

[0068] Specifically, the disclosure may be (1) a configuration in which a bypass function is executed when the first and second requirements are satisfied, (2) a configuration in which a bypass function is executed when the third requirement is satisfied, (3) a configuration in which a bypass function is executed when the fourth requirement is satisfied, or (4) a configuration in which a bypass function is executed when the first requirement is satisfied, etc.

[0069] In the normal control according to the embodiment described above, the drive frequency is controlled so that the suction temperature becomes the set temperature. However, the present disclosure is not limited to this. That is, the present disclosure may be configured, for example, so that the drive frequency is controlled so that the blowing temperature becomes a preset temperature, and the airflow rate of the electric fan 6 is controlled as a function value of the rotation speed (drive frequency) of the compressor 2.

[0070] The first requirement in the above-described embodiment is that "the suction temperature is higher than the introduction start temperature." However, the present disclosure is not limited to this. That is, the present disclosure may be configured such that the first requirement is, for example, that "the blowing temperature is higher than a predetermined temperature."

[0071] In the above embodiment, the damper 8B is closed when the requirement is not met. However, the present disclosure is not limited to this. That is, the present disclosure may be configured such that the damper 8B is slightly open when the requirement is not met, that is, the amount of introduced air is greater than 0 even when the requirement is not met.

[0072] In the above embodiment, the server room SR is separated into a cold aisle and a hot aisle, and the air conditioner 10 supplies cool air to the cold aisle. However, the present disclosure is not limited to this. That is, in the present disclosure, for example, the server room SR does not need to be separated into a cold aisle and a hot aisle.

[0073] Furthermore, the present disclosure is not limited to the above-mentioned embodiments as long as it is consistent with the gist of the disclosure described in the above-mentioned embodiments. Therefore, the present disclosure may be a configuration in which at least two of the above-mentioned embodiments are combined, or a configuration in which any of the components illustrated or the components described with reference numerals in the above-mentioned embodiments are eliminated. [Explanation of symbols]

[0074] 1. Vapor compression refrigerator 2. Compressor 3… Heatsink 4… Pressure reducer 5. Evaporator 6. Electric fan 7… Indoor unit 8A... Bypass passage 8B... Damper 8...Reflux device 9... Control device 10…Air conditioner

Claims

[Claim 1] An air conditioner that is configured with a low-pressure side heat exchanger of a vapor compression type refrigeration unit having a compressor, has a heat exchanger that cools air drawn from inside a room, and supplies the cooled air to the room, a temperature sensor that detects a temperature of the air before being cooled by the heat exchanger or the air after being cooled by the heat exchanger; a circulation device for introducing at least a portion of the air cooled by the heat exchanger (hereinafter referred to as cold air) into an air flow upstream side of the heat exchanger; Equipped with an electric fan that blows cool air into the room, The reflux device has a function of increasing the amount of cool air introduced upstream (hereinafter referred to as the introduced air volume) when the temperature detected by the temperature sensor (hereinafter referred to as the heat load temperature) is higher than a predetermined temperature (hereinafter referred to as the introduction start temperature) compared to when the heat load temperature is equal to or lower than the introduction start temperature; and The rotation speed of the compressor is a predetermined rotation speed (hereinafter referred to as the introduction start rotation speed). ) is larger than the introduction start rotation speed, the introduction air volume is increased compared to when the rotation speed is lower than the introduction start rotation speed. An air conditioning device having the above structure.

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