JPH09250822A - Refrigerating cycle apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove effectively moisture mixed in a refrigerant or in a refrigerating machine oil before such moisture is iced or exerts adverse effect by a reaction of the moisture with the refrigerating machine oil. SOLUTION: A dryer 6 is provided in an oil return pipe 11 between an oil separator 10 and a compressor 2, and the prioritized adsorption and removal of moisture in a refrigerating machine oil are carried out during the operation of refrigerating cycle apparatus. Further, the refrigerating machine oil to be returned to the compressor 2 via the oil separator 10 is returned directly to the compressor 2, or is returned to a suction pipe adjacent to the compressor 2, thereby holding a moisture concentration in the refrigerating machine oil at a low level and preventing the refrigerating machine oil from deteriorating. Furthermore, during trial operation, moisture is adsorbed by using the dryer while increasing an amount of a refrigerant to be circulated in the cycle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dryer for the purpose of removing water in a refrigeration cycle apparatus and a method of operating the dryer during a test operation.

[0002]

2. Description of the Related Art Refrigerant used in recent refrigeration cycle equipment is HCFC or HF which is an alternative refrigerant from conventional CFC.
It is being transferred to C. Along with this, ester-based refrigerating machine oil is often used as refrigerating machine oil corresponding to these alternative refrigerants.

[0003] However, ester-based refrigerating machine oil is hydrolyzed by reacting with water, and further reacts with a metal to form a metal salt in a closed system of the refrigerating cycle device.
This reaction promotes deterioration of refrigerating machine oil, and the generated metal salt is accumulated in the expansion device in the refrigeration cycle device,
It has been pointed out that it may cause blockage of piping. Until now, by installing a dryer in the refrigeration cycle device,
The low temperature prevented the freezing of water and the clogging of the squeezing device.

FIG. 3 is a basic block diagram of a refrigeration cycle apparatus incorporating a dryer. In FIG. 3, as the configuration of the refrigeration cycle device, one outdoor unit and one indoor unit (A and B)
The multi-air-conditioning system consisting of two units is shown, and the compressor 2, the four-way valve 3, the outdoor heat exchanger 4, the heating expansion device 5, the dryer 6, the cooling expansion devices 7-A and 7-B, the indoor heat exchange are shown. Vessels 8-A and 8-B, accumulator 9, oil separator 10, oil return pipe 11, power supply device 12, control device 1
3 is a constituent element, and the constituent elements 2 to 11 are connected by a pipe 1. The oil return pipe 11 is connected between the oil separator 10 and the compressor 2, and is connected from the oil separator 10 to the compressor 2
The HFC-based mixed refrigerant and the ester-based refrigerating machine oil are enclosed in the refrigerating cycle device.

Incidentally, the mixed refrigerant and the refrigerating machine oil contain water mixed in at the time of manufacturing or pipe construction. In order to remove the moisture, a granular molecular sieve widely used as a moisture adsorbent is enclosed inside the dryer 6, and the molecular sieve is provided at the refrigerant inlet and outlet of the dryer 6. A screen mesh is installed in order to prevent outflow into the refrigeration cycle apparatus 1.

Here, the refrigeration cycle apparatus changes the flow of the refrigerant in the pipe 1 by switching the four-way valve 3, and during the cooling operation, the outdoor heat exchanger 4 serves as a condenser and the indoor heat exchanger 8- A and 8-B are the evaporators, the compressor 2,
Four-way valve 3, outdoor heat exchanger 4, heating expansion device 5, dryer 6, cooling expansion devices 7-A and 7-B, indoor heat exchangers 8-A and 8-B, four-way valve 3, accumulator 9,
In the heating operation, the outdoor heat exchanger 4 serves as an evaporator, and the indoor heat exchangers 8-A and 8-B serve as condensers in the order of the compressor 2, the compressor 2, the four-way valve 3, and the indoor. The heat exchangers 8-A and 8-B, the cooling expansion devices 7-A and 7-B, the dryer 6, the heating expansion device 5, the outdoor heat exchanger 4, the four-way valve 3, the accumulator 9, and the compressor 2 in this order. A refrigerant flows.

Further, the oil separator 10 has a role of returning the refrigerating machine oil contained in the high-temperature and high-pressure refrigerant discharged from the compressor 2 to the compressor 2 without circulating the refrigerating machine oil through the oil return pipe 11 in the refrigeration cycle. are doing.

In the trial operation mode in the conventional refrigeration cycle apparatus, after the construction of the refrigeration cycle apparatus 1, the frequency of the compressor is short in the vicinity of the frequency during normal operation for the purpose of checking the operation of the refrigeration cycle system and the control system. I'm only doing it.

[0009]

By using a dryer to adsorb all the water mixed in the refrigeration cycle, hydrolysis of the ester-based refrigerating machine oil can be prevented. At this time, the molecular sieve in the dryer removes the water. The relationship between the adsorbing speed and the speed at which ester-based refrigerating machine oil reacts with water to cause ester decomposition becomes a problem. In other words, if the water reacts with the refrigerating machine oil and is hydrolyzed before the water is adsorbed by the molecular sieve, the deterioration of the refrigerating machine oil, which is the purpose of installing the dryer, cannot be prevented. Although it is not possible to make a simple comparison between the rate of water adsorption by the molecular sieve and the rate of hydrolysis by the refrigerating machine oil, it is essential to adsorb moisture by the molecular sieve as soon as possible during the trial run of the refrigeration cycle apparatus.

In practice, however, the operation of the refrigeration cycle was only checked in a short time, and no operation was devised to adsorb and remove water with a dryer as quickly as possible. Further, in order to reduce the reaction with the refrigerating machine oil, it is considered effective to reduce the water concentration in the refrigerating machine oil of the refrigeration cycle device as much as possible. It wasn't done at all.

From this point of view, the present invention effectively removes the water mixed in the refrigeration cycle, particularly while keeping the water concentration in the refrigeration oil preferentially low, to thereby achieve the refrigeration cycle oil in the refrigeration cycle apparatus. The purpose of this is to prevent deterioration due to hydrolysis and to improve reliability.

[0012]

According to the present invention, a drier for the purpose of reducing the water concentration in refrigerating machine oil is installed in an oil return pipe section, and refrigerating machine oil discharged from a compressor passes through an oil separator. The moisture in the refrigerating machine oil is adsorbed and removed by the dryer in the oil return pipe section while circulating to the compressor again, so that the moisture concentration in the refrigerating machine oil is always kept low and hydrolysis in the refrigerating machine oil is prevented. It is characterized in that the moisture is adsorbed through the dryer while being suppressed.

Further, according to the present invention, when the refrigerating machine oil is circulated in the system in which the refrigerating machine oil enters the oil separator through the high pressure discharge pipe from the compressor and returns to the compressor through the oil return pipe in the trial operation (initial operation mode) In the refrigeration cycle apparatus, it is characterized in that it prevents passage from the evaporator outlet having a relatively high water content through the pipe portion of the compressor suction pipe. At this time, in order to make the refrigerating machine oil returning to the compressor as little as possible through the suction pipe, the oil return pipe is directly connected to the compressor or is connected to the suction pipe as close as possible to the compressor. As a result, the water concentration in the refrigerating machine oil becomes low, and it becomes possible to prevent the refrigerating machine oil from undergoing a hydrolysis reaction with water.

Further, according to the present invention, in order to solve the above-mentioned problems, in the trial operation mode performed after the construction of the refrigeration cycle apparatus, the compressor is operated at a high frequency, depending on the scale of the refrigeration cycle apparatus and the amount of mixed water. By increasing the refrigerant circulation amount and continuously operating for a set time according to the scale of the refrigeration cycle device, the efficiency of water adsorption by the molecular sieve is improved, and by the molecular sieve before the refrigerating machine oil undergoes hydrolysis reaction with water. By adsorbing water, deterioration of refrigerating machine oil can be suppressed.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention (1) The most important thing for suppressing hydrolysis is to keep the water concentration in the refrigerating machine oil as low as possible until the water adsorption by the molecular sieve is completed, Further, (2) a configuration made based on a new finding that most of the water mixed in the refrigeration cycle device is condensed and accumulated in the piping part of the compressor suction pipe from the evaporator outlet where the temperature is low and low pressure, and (3) The moisture adsorption rate in the molecular sieve is based on the fact that it is faster as the refrigerant around the molecular sieve is actively flowing.

Specific examples of the present invention will be described below. (Embodiment 1) FIG. 1 shows an embodiment of the refrigeration cycle apparatus of the present invention. It should be noted that elements common to those in FIG. 3 showing the basic configuration are designated by the same reference numerals and described. FIG. 1 shows a multi-air-conditioning system with one indoor unit and two indoor units as the configuration of the refrigeration cycle apparatus. The compressor 2, the four-way valve 3, the outdoor heat exchanger 4, the heating expansion device 5 are shown. , Dryer 6,
Cooling expansion devices 7-A and 7-B, indoor heat exchanger 8-
A and 8-B, the accumulator 9, the oil separator 10, the oil return pipe 11, the power supply device 12, and the dryer 14, and the compressor 2, the heating expansion device 5, and the cooling expansion device 7-A. Control device 1 for controlling 7-B, etc.
The refrigeration cycle apparatus is composed of three. 2 to 11
The respective equipments 14 and 14 are connected by a connection pipe 1 to form a heat pump cycle, and an HFC-based mixed refrigerant and an ester-based refrigerating machine oil are enclosed in the refrigerating cycle device. Here, the oil return pipe 11 is connected to the compressor 2
It serves to return the refrigerating machine oil discharged from the compressor to the compressor again via the oil separator 10.

In the dryer 6 and the dryer 14,
Granular molecular sieves widely used as a water adsorbent are enclosed, and the molecular sieves flow into the refrigeration cycle apparatus 1 at the refrigerant / oil inlets and outlets of the dryer 6 and the dryer 14. To prevent this, a screen mesh is installed.

The outdoor unit includes a compressor 2, a four-way valve 3,
The indoor heat exchanger 4, the heating expansion device 5, the dryer 6, the accumulator 9, the oil separator 10, the oil return pipe 11, the power supply device 12, and the control device 13 are composed of the indoor unit A and the indoor unit. B are cooling expansion devices 7-A and 7-B, and indoor heat exchangers 8-A and 8-B, respectively.
It is composed of

In the refrigerating cycle apparatus, the water dissolved in the refrigerant and the refrigerating machine oil when the refrigerant and the refrigerating machine oil are enclosed, and the water entering from the pipe 1 temporarily opened to the outside during construction are , It is mixed in the refrigeration cycle device.

In the test operation immediately after construction of the refrigeration cycle apparatus in FIG. 1, most of the refrigerating machine oil discharged from the compressor 2 is separated from the refrigerant by the oil separator 10, and the refrigerating machine oil passes through the oil return pipe 11 and the compressor. Returned to 2. On this occasion,
The dryer 14 installed in the suction pipe 14 to the compressor 2 adsorbs and removes the water dissolved in the oil, so that the water concentration contained in the refrigerating machine oil is kept low preferentially and the refrigerating machine oil and the water are separated. It becomes possible to suppress hydrolysis.

(Embodiment 2) Further, during the trial operation of the refrigeration cycle apparatus, the oil separator 10 separates the refrigerating machine oil contained in the high temperature and high pressure refrigerant discharged from the compressor 2 by using the oil separator 10 as much as possible. However, by not returning it to the constituent elements of the refrigeration cycle apparatus including the four-way valve 3 or less, but directly returning to the compressor 2 / the suction pipe 14 close to the compressor 2, the evaporator inlet to
By performing lubrication in the compressor 2 without passing through a portion of the suction pipe 1 of the compressor 2 where much water is accumulated,
Since the amount of water in the refrigerating machine oil can be kept low without impairing the function of the refrigerating machine oil, deterioration of the refrigerating machine oil due to water can be prevented as a result.

(Embodiment 3) Further, in performing the initial operation (test operation), the frequency of the compressor 2 is operated at a high capacity of the operation mode set in the refrigeration cycle apparatus, and the refrigerant circulation amount in the refrigeration cycle apparatus is increased. The moisture is removed by using the dryer 6 and the dryer 14 while increasing the temperature.

FIG. 2 shows a typical example of changes in the amount of water in the refrigeration cycle apparatus when the compressor frequency is operated at a low speed and when it is operated at a high speed. In FIG. 2, the horizontal axis represents the passage of time and the vertical axis represents the change in the amount of water in the refrigeration cycle apparatus. As shown in FIG. 2, it can be seen that the amount of water in the refrigeration cycle apparatus decreases in a short time when the compressor is operated at a high frequency.

It is also confirmed from experiments that this is because the amount of the refrigerant circulating in the dryer 6 and the dryer 14 is increased, and the moisture adsorption rate and efficiency of the molecular sieve in the dryer 6 and the dryer 14 are improved. There is. In this way, by operating the compressor at a high frequency for a set time according to the scale of the refrigeration cycle device,
Moisture in the refrigeration cycle apparatus can be absorbed in a short time, and as a result, deterioration of refrigerating machine oil can be prevented.

[0025]

As described above, after performing the operation in the refrigeration cycle apparatus, when performing the operation with at least one of the purposes of removing the water mixed in the refrigeration cycle apparatus using the dryer, By installing a dryer in the oil return pipe section that returns the refrigeration oil from the oil separator to the compressor, and adsorbing and removing the moisture, the moisture mixed in the refrigeration oil is preferentially removed, thereby preventing deterioration due to hydrolysis of the refrigeration oil. It becomes possible to prevent it.

Further, the refrigerating machine oil is returned to the compressor or the suction pipe section near the compressor by an oil separator installed between the compressor and the four-way valve, and the refrigerating machine oil is circulated between the compressor and the oil separator. Thus, the water concentration in the refrigerating machine oil can be kept low, and deterioration of the refrigerating machine oil due to hydrolysis can be prevented.

Further, by increasing the circulation speed of the refrigerant and operating for a set time or longer, it becomes possible to adsorb and remove the water dissolved in the refrigerant more quickly by using a dryer.

By the means as described above, the moisture in the refrigeration cycle apparatus is adsorbed and removed, and the deterioration of the refrigerating machine oil in the refrigeration cycle apparatus is prevented, so that the reliability can be improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a refrigeration cycle apparatus according to one embodiment of the present invention.

FIG. 2 is a diagram showing changes in the amount of water in the refrigeration cycle apparatus according to one embodiment of the present invention.

FIG. 3 is a configuration diagram of a conventional refrigeration cycle device.

[Explanation of symbols]

 1 Connection piping 2 Compressor 3 Four-way valve 4 Outdoor heat exchanger 5 Heating expansion device 6 Dryer 7-A, 7-B Cooling expansion device 8-A, 8-B Indoor heat exchanger 9 Accumulator 10 Oil separator 11 Oil return piping 12 Power supply device 13 Refrigeration cycle device control device 14 Oil separator dryer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuji Yoshida 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (3)

[Claims] 1. A compressor, an outdoor heat exchanger, a throttle device, an indoor heat exchanger, at least one accumulator, and a four-way valve, each of which is connected by a pipe to form a heat pump cycle. Then, a refrigerant and an ester-based refrigerating machine oil are enclosed inside, an oil separator is installed between the compressor and the four-way valve, and the refrigerating machine oil is fed from the oil separator to the compressor or the compressor suction pipe. A refrigeration cycle device characterized in that a dryer is provided on the oil return pipe for returning the oil. 2. A compressor, an outdoor heat exchanger, a throttling device, an indoor heat exchanger, at least one accumulator and four-way valve, each of which is connected by a pipe to form a heat pump cycle. Then, a refrigerant and an ester-based refrigerating machine oil are enclosed inside, an oil separator is installed between the compressor and the four-way valve, and the refrigerating machine oil is fed from the oil separator to the compressor or the compressor suction pipe. A refrigeration cycle apparatus characterized in that an oil return pipe for returning the oil is provided, and the refrigerating machine oil discharged from the compressor is returned directly to the compressor through the oil return pipe or to an intake pipe close to the compressor. . 3. A compressor, an outdoor heat exchanger, a throttle device, an indoor heat exchanger, at least one accumulator and a four-way valve, each of which is connected by a pipe to form a heat pump cycle. Then, a dryer for the purpose of adsorbing water is installed at at least one place of the heat pump cycle, and after the refrigerant and the ester-based refrigerating machine oil are filled in the refrigerating cycle device, the refrigerant of the refrigerating cycle device and Adsorption and removal of water through the dryer while mixing in the refrigerating machine oil and operating the compressor in a set high-frequency operation mode for a predetermined time or longer to increase the amount of circulating refrigerant passing through the dryer. A refrigeration cycle apparatus having an operation mode for performing the above.