JP3480076B2 - Outdoor unit - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner or the like which uses a refrigerant as a working fluid which is harmful to the global environment and whose future production is planned to be reduced or prohibited. Related to a refrigeration apparatus. 2. Description of the Related Art The control of a refrigeration cycle applied to an air conditioner is disclosed in JP-A-2-230055, in which the temperature of the refrigeration cycle is detected by a detecting device, and the detected value is detected. There is known a method of controlling an expansion opening degree to a predetermined temperature by a control device based on the above. Another known method is to detect the temperature and pressure during a cycle by a detecting device and to control the compressor operating frequency, blower air flow, bypass solenoid valve on / off, bypass expansion valve, and the like by a control device. As described in JP-A-2-230054, there is known a method of detecting the temperature of a refrigeration cycle by a detection device, performing a control to determine an abnormality by a control device based on the detected value, and stopping the compressor. ing. Further, there is known a method in which a controller detects a cycle abnormality by detecting each temperature, pressure, and current value in a refrigeration cycle by a detector. [0003] In recent years, there has been a plan to restrict or prohibit the production of fluorocarbon-based refrigerants containing chlorine that destroys ozone by means of the so-called Montreal Protocol Parties, etc. from the viewpoint of environmental protection. But are negotiated internationally. In the future, if the production of fluorinated hydrocarbon-based refrigerants containing chlorine is reduced or banned, the availability is expected to deteriorate and the price will rise. For the time being, if a refrigeration system using a fluorocarbon refrigerant containing chlorine to be manufactured needs to open the refrigeration cycle for replacement of parts due to maintenance, failure, etc. It is anticipated that there will be a need to switch to a fluorocarbon-based refrigerant containing no chlorine which does not destroy the ozone layer. However, when the refrigerant is simply replaced, the refrigerating machine oil has a problem in that the thermodynamic properties and the transport characteristics of the refrigerant are different, so that some parts cannot be applied by the same control as before the refrigerant replacement. [0004] The refrigerant of the refrigeration system is, for example, R2
According to 2, there is a case where the capacity is remarkably changed due to the relationship between the density, latent heat and specific heat of the refrigerant without changing the equipment to be replaced with R134a, for example. At this time, it is necessary to change not only the control content but also the circulation amount of the compressor in order to obtain the same capacity as the refrigerant before the replacement. Also, depending on the refrigerant and the refrigerating machine oil after replacement, the compatibility with organic materials such as polyester-based insulating materials, enamels and varnishes used in the compressor is poor, which may lead to deterioration and deterioration of the organic materials and refrigerating machine oil. There is a problem that the reliability of the compressor is reduced. [0005] Further, if there is no means for confirming the used refrigerant after changing the refrigerant, the refrigerant used in the refrigeration system cannot be known, and there is a problem that the refrigerant is erroneously sealed during service. An object of the present invention is to provide a refrigeration system that can operate normally even when the refrigerant used for the refrigeration system is changed. Still another object of the present invention is to provide a refrigeration apparatus that can easily confirm the type of refrigerant used even when the refrigerant used for the refrigeration apparatus is changed. [0007] In order to achieve the above object, according to the present invention, a control method suitable for at least one new refrigerant as a substitute candidate is provided in the control device in advance, and the refrigerant of the refrigerating device is provided. When the fluorine-containing hydrocarbon refrigerant containing chlorine is replaced with a fluorine-containing hydrocarbon refrigerant that does not contain chlorine and is used, a switching means is used to change the control method to a control method suitable for the chlorine-free fluorine-containing hydrocarbon refrigerant. Further, in order to achieve the above object, means for changing the control content and changing the refrigerant compression device to one adapted to the new refrigerant is adopted. Further, in order to achieve the above-mentioned object, there is provided a display means capable of confirming the type of the refrigerant in conjunction with the switching means. According to the present invention, in a refrigeration system using a fluorinated hydrocarbon-based refrigerant containing chlorine as a working fluid, if the refrigerant is discharged and re-sealed due to maintenance, failure, etc., the sealing is performed. Even if the refrigerant is changed to a fluorinated hydrocarbon-based refrigerant that does not contain chlorine, it is possible to operate the refrigeration cycle normally by changing the control to a control suitable for the refrigerant after the change by using the above means. Become. Further, by changing the compressor to one adapted to the new refrigerant, the amount of circulation can be changed, and furthermore, the deterioration and deterioration of the organic material used in the compressor and the refrigerating machine oil can be prevented. In addition, by displaying the type of the refrigerant used as the working fluid in conjunction with the switching means, the type of the refrigerant sealed in the refrigerating apparatus can be easily confirmed. An embodiment of the present invention will be described below. FIG. 1 shows a refrigeration cycle of an air conditioner according to an embodiment of the present invention, and shows an example of an air conditioner capable of performing cooling and heating operations by combining one outdoor unit with one indoor unit. I have. First, the configuration of the embodiment will be described. First, the outdoor unit has a compressor 1, a four-way valve 2, an outdoor blower 4, an outdoor expansion valve 5,
Bypass solenoid valves 11, 12, liquid bypass expansion valve 13, temperature sensor 14 provided on the compressor discharge side, discharge pressure sensor 15, suction pressure sensor 1 provided on the compressor suction side
6. The outside air temperature sensor 17 provided on the outdoor suction side is connected to the outdoor control device 22 by a signal line. The outdoor control board 27 includes a control switching device 23, a display device 26, and an outdoor control device 22. The control switching device 23 and the display device 26 are connected to the outdoor control device 22. Further, an accumulator 10, a receiver 6, and an outdoor heat exchanger 3 are provided. On the indoor unit side, the indoor blower 9, the indoor expansion valve 7, the indoor liquid pipe temperature sensor 18, the indoor gas pipe temperature sensor 1
9, indoor air temperature sensor 20, indoor air temperature sensor 21
Are connected to the indoor control device 24 via signal lines. Also,
An indoor heat exchanger 8 is provided. A remote controller 25 that can set air conditions such as an indoor air temperature where the indoor unit is installed and an indoor control device 24 are connected by a transmission line, and the indoor control device 24 and the outdoor control device 22 are connected by a signal line. It is connected. By the way, the outdoor control device 22 stores control contents suitable for several kinds of refrigerants as candidates for the alternative refrigerant when the air conditioner needs to replace the refrigerant with the alternative refrigerant. If the refrigerant is replaced,
The control switching device 23 switches the control content of the outdoor control device 22. In this figure, the flow of the refrigerant is in the direction of the solid line during the cooling operation and in the direction of the dotted line during the heating operation. Next, the operation of the air conditioner of this embodiment will be described. As an example, the operation of the compressor 1, the liquid bypass expansion valve 13, and the indoor expansion valve 8 during the cooling operation will be described. The operating frequency of the compressor 1 is controlled so that the control target suction pressure calculated by the outdoor controller 22 is obtained from the value detected by the suction pressure sensor 16. For example, when the room temperature becomes low and the evaporation capacity of the indoor heat exchanger 8 decreases, the suction pressure decreases. When the suction pressure falls below the target value, control is performed to reduce the compressor operating frequency, and the suction pressure rises due to a decrease in the circulation amount, and stabilizes at the target suction pressure. Here, when the refrigerant of the working fluid is changed, the compressor 1
The control operation of the outdoor control device 22 is controlled by the control switching device 23 in consideration of the difference in the saturation pressure of the refrigerant after the change, and the compressor operation such as the target suction pressure, the speed at which the operating frequency of the compressor 1 increases and decreases, and the amount of the increase and decrease. By driving with the control changed to the specification, the refrigeration apparatus can operate normally. The liquid bypass expansion valve 13 is controlled so that the control target discharge temperature calculated by the outdoor control device 22 from the value detected by the discharge temperature sensor 14 is obtained.
Is controlled. For example, when the value detected by the discharge temperature sensor 14 increases, the opening degree of the liquid bypass expansion valve 13 increases, the amount of the liquid refrigerant flowing into the accumulator 10 increases, and the enthalpy of the refrigerant sucked into the compressor 1 decreases. By doing so, the discharge temperature decreases and stabilizes at the target discharge temperature. Here, when the refrigerant of the working fluid is changed, a difference in the thermodynamic characteristics and transport characteristics of the refrigerant, and when the changed refrigerant has two or more components, the composition ratio of the refrigerant in the accumulator changes, and the like. A change occurs in the thermodynamic characteristics and transport characteristics of the refrigerant. Therefore, the liquid bypass expansion valve 13
The control switching device 23 changes the control content of the outdoor control device 22 into the target discharge temperature and the opening / closing speed of the opening / closing rate of the liquid bypass expansion valve 13 in consideration of the above-mentioned characteristics of the changed refrigerant. Normal operation is possible by driving with the control changed to the specification. The indoor expansion valve 7 is provided with an indoor liquid pipe temperature sensor 18.
The opening is controlled so that the difference between the indoor heat exchange inlet temperature detected by the indoor gas pipe temperature sensor 19 and the indoor heat exchange outlet temperature becomes the target temperature difference, and the amount of refrigerant flowing into the indoor heat exchanger 8 is adjusted. . Here, when the refrigerant of the working fluid is changed to the non-azeotropic mixed refrigerant, and when the composition of the refrigerant is one, the difference between the indoor heat exchange inlet temperature and the indoor heat exchange outlet temperature is determined by the indoor heat exchanger 8. The temperature becomes the sum of the temperature drop due to the pressure loss of the refrigerant between the inlet and the outlet and the degree of superheat. By the way, in the evaporation process under the condition of equal pressure, the temperature of the refrigerant does not increase when the composition of the refrigerant is one, but the temperature of the refrigerant increases due to the temperature gradient of the non-azeotropic mixed refrigerant. That is, in the non-azeotropic refrigerant mixture, the difference between the indoor heat exchange inlet temperature and the indoor heat exchange outlet temperature is determined by the temperature gradient in the evaporation process and the indoor heat exchanger 8 inlet,
The temperature is the sum of the temperature drop due to the pressure loss between the outlets and the degree of superheat. Therefore, when the target temperature difference between the indoor heat exchange inlet temperature and the indoor heat exchange outlet temperature is changed to a non-azeotropic mixed refrigerant, it must be set to a value in consideration of the temperature gradient. Therefore, the indoor expansion valve 7 is provided with a target temperature difference between the indoor heat exchange inlet temperature and the indoor heat exchange outlet temperature in consideration of the characteristics of the refrigerant after the control content of the outdoor control device 22 is changed by the control switching device 23, and the indoor expansion valve. By driving with the control changed to the opening specification such as the speed of increase / decrease change and the amount of increase / decrease change of the opening of 7,
The refrigeration system can operate normally. Next, a description will be given of an embodiment of a device for displaying the type of refrigerant whose control content is switched by the control switching device 23 of FIG. When the control switching device 23 is set to control a predetermined refrigerant, the outdoor control device 22 identifies the type of the refrigerant and displays the type of the refrigerant on the display device 26. By displaying the type of the refrigerant on the display device 26, the refrigerant used in the refrigeration system can be clearly identified, and if the refrigerant replacement operation occurs due to replacement of a component due to a failure after the refrigerant exchange, the operation can be performed smoothly. Further, since the control switching device 23 and the display device 26 are connected, it is possible to confirm whether the refrigerant used as the working fluid in the refrigeration device matches the setting of the control switching device 23. Also,
A remote controller 25 having a display function for displaying a refrigerant type, an outdoor unit control board 27 having an LED,
A method of displaying the type of refrigerant by providing seven segments, a method of displaying the type of refrigerant on a failure diagnosis system for diagnosing a failure from outside, or a centralized management system for centrally controlling a plurality of outdoor units and indoor units may be used. . Next, FIGS. 2, 3, 4 and 5 show an embodiment of a control switching device provided on the outdoor control board 27. FIG.
FIG. 2 shows a switch that can be set on / off. By providing several switches that can be set to this ON / OFF, it is possible to switch several types of control contents by a combination of ON / OFF. In addition, the combination of ON / OFF setting and ON / OFF may be a combination of not cutting the plurality of wirings as shown in FIG. In FIG. 4, several types of control can be switched by turning a dial type switch and setting the dial to a predetermined position. Further, it can be switched by setting a slide switch as shown in FIG. 5 to a predetermined position. Table 1 shows examples of refrigerants that are compatible with one embodiment of the present invention. [Table 1] As a refrigerant whose production is to be reduced or prohibited to destroy the ozone layer, HCFC2 shown in the table is used.
2 is mentioned. As a substitute refrigerant for the HCFC 22, a refrigerant using a fluorinated hydrocarbon-based refrigerant containing no chlorine alone or in a mixture is influential, and there is a refrigerant which can achieve the same performance without a hardware change of equipment. In addition, a refrigerant developed as an alternative refrigerant to R502 can be used in some cases, and control suitable for at least one fluorinated hydrocarbon-based refrigerant containing no chlorine as shown in Table 1. By setting the contents in the control device in advance, the control contents can be selected and used appropriately by switching means such as switches. The refrigerant numbers shown in the table are given by ASHRAE,
These refrigerants are being studied for practical use. By the way, when the refrigerant of the refrigeration system is changed from R22 to, for example, R134a, the refrigerant density, latent heat,
In some cases, the capacity varies significantly depending on the specific heat. At this time, in order to obtain the same capacity as the refrigerant before the exchange, it is necessary to change not only the control content but also the circulation amount of the compressor. In addition, some non-chlorine-based refrigerants and refrigerating machine oil refrigerants suitable for the non-chlorine-based refrigerants chemically react with organic materials such as polyester-based insulating materials, enamels, and varnishes used in compressors, thereby transforming the organic materials and refrigerating machine oil. , May deteriorate. In such a case, as in the case of the switching of the control shown in the present embodiment, if the method of changing the compressor to the one adapted to the replaced refrigerant is adopted, a refrigeration device more suitable for the replaced refrigerant can be used, and the compressor can be used for the compressor. Organic materials,
In addition, deterioration and deterioration of the refrigerating machine oil can be suppressed, and the reliability can be improved. According to the present invention, the normal operation of the refrigeration cycle is switched to the control suitable for the refrigerant to be used by the switching device, even if the type of the refrigerant used for the refrigeration system is changed. Since it becomes possible by this, even if the refrigeration system using a fluorinated hydrocarbon-based refrigerant containing chlorine as a working fluid is changed to a fluorinated hydrocarbon-based refrigerant containing no chlorine as an alternative refrigerant,
It can be easily changed to a refrigerating device that supports the alternative refrigerant, and normal operation can be performed. Also, by displaying the type of the refrigerant used as the working fluid in conjunction with the switching means, the type of the refrigerant sealed in the refrigeration apparatus can be easily confirmed. Reliable operation of refrigerant change. In addition, since the type of the refrigerant after the change can be displayed, the operation of confirming the type of the refrigerant becomes easy. From the above, maintenance workability can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a refrigeration cycle of an air conditioner according to an embodiment of the present invention. FIG. 2 is an explanatory diagram of one embodiment of a control switching device. FIG. 3 is an explanatory diagram of a second embodiment of the control switching device. FIG. 4 is an explanatory diagram of a third embodiment of the control switching device. FIG. 5 is an explanatory diagram of a fourth embodiment of the control switching device. [Description of Signs] 1 ... Compressor, 3 ... Outdoor heat exchanger, 5 ... Outdoor expansion valve, 7 ...
Indoor expansion valve, 8: indoor heat exchanger, 10: accumulator, 11, 12: bypass solenoid valve, 13: bypass expansion valve, 15, 16: pressure sensor, 14, 17 to 21: temperature sensor, 22: outdoor control device , 23 ... Control switching device, 2
6. Display device.

Continuation of the front page (72) Inventor Hiroaki Matsushima 502 Kandachi-cho, Tsuchiura-shi, Ibaraki Machinery Research Laboratory, Hitachi, Ltd. (56) References JP-A-6-193981 (JP, A) JP-A-5-272851 (JP) , A) JP-A-7-253250 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F25B 1/00 395 F25B 49/02 510

Claims (1)

(57) [Claims] [Claim 1] Compressor, four-way valve, outdoor heat exchanger, outdoor expansion
Valves are sequentially connected and provided on the discharge side of the compressor.
Temperature sensor and discharge pressure sensor, provided on the suction side
Suction pressure sensor, outside air temperature sensor provided on the outdoor suction side
In the outdoor unit in which the temperature sensor, the discharge pressure sensor, the suction pressure sensor, and the outside air temperature sensor are connected by signal lines, and an outdoor control device in which control contents suitable for a plurality of refrigerants are stored; A control switching device for switching the contents and a display device for displaying the type of refrigerant are provided, and the type of the refrigerant is displayed in conjunction with the control switching device.
At the same time, the compressor increases or decreases the target suction pressure and operating frequency.
It is driven by the control contents with the change speed and the change amount changed.
An outdoor unit, characterized in that: