JPH05180520A - Freezing cycle device - Google Patents

Abstract

PURPOSE:To prevent burning loss of a compressor caused by a lack of feeding oil to a sliding part which is produced by phenomenon of generating bubbles when the first and second compressors arranged in parallel to each other are energized. CONSTITUTION:The second compressor 2 arranged in parallel with the first compressor 1 during the same freezing cycle and driven by an inverter 11 is energized under an energizing frequency. In the case that a heating temperature of discharged gas calculated by a discharged gas refrigerant heating temperature calculation means 13 in reference to the discharged gas pressure and its temperature is more than the predetermined heating temperature set value, the first compressor 1 is energized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration cycle apparatus in which compressors are connected in parallel, and more particularly to start-up control thereof.

[0002]

2. Description of the Related Art FIG. 5 shows, for example, JP-A-63-29778.
It is a block diagram of the conventional refrigeration cycle apparatus shown by the 6th publication. In the figure, 1 is a first compressor having a predetermined capacity, 2 is a second compressor which is connected in parallel to the first compressor 1 and whose capacity is controlled by inverter drive, and 3 separates refrigerating machine oil from discharge gas. Oil separator 4, four-way switching valve for switching the refrigerant flow path, 5 non-use side heat exchanger, 6a and 6b decompressor, 7a and 7b use side heat exchanger, 8 accumulator, 9 oil separator An oil returning circuit for returning the refrigerating machine oil collected in 3; 10 is an oil equalizing pipe for equalizing the refrigerating machine oil amounts of the compressors 1 and 2; 11 is a variable driving speed of the second compressor 2 An inverter, a start control device 13 for the compressors 1 and 2, and a first timer means 12. In the figure, the solid line arrow indicates the refrigerant flow direction during the cooling operation, and the broken line arrow indicates the refrigerant flow direction during the heating operation.

Next, the operation of the refrigeration cycle will be described. During the cooling operation, the first or second compressor 1, 2
The high-temperature and high-pressure gas refrigerant compressed in (3) enters the oil separator 3 to separate refrigerating machine oil contained in the gas refrigerant, and enters the non-use side heat exchanger 5 via the switching valve 4. In the non-use side heat exchanger 5, the heat is radiated to the atmosphere or the heat source water, and the refrigerant is condensed to become a high-pressure liquid refrigerant, which is decompressed by the decompression devices 6a and 6b and becomes a low-pressure gas-liquid mixed refrigerant, and the use side It flows into the heat exchangers 7a and 7b. In the use side heat exchangers 7a and 7b, heat is taken from the indoor air to evaporate the refrigerant to achieve cooling operation. The low-pressure gas refrigerant gasified in the use-side heat exchangers 7a and 7b enters the accumulator 8 through the four-way switching valve 4, separates the unevaporated refrigerant liquid and the gas refrigerant, and only the gas refrigerant is the first or It is sucked into the second compressors 1 and 2. In addition, the operating states of the use side heat exchangers 7a and 7b can be individually selected,
When stopping, the capacity control operation is performed by closing the pressure reducing devices 6a and 6b.

Next, the operation of the refrigeration cycle during the heating operation will be described. During heating operation, by switching the four-way switching valve 4 to the side of the broken line, the high-temperature and high-pressure gas refrigerant discharged from the compressors 1 and 2 is passed through the oil separator 3 and the four-way switching valve 4 to the use side heat exchanger. The refrigerant flows into 7a and 7b and radiates heat to the room air to perform a heating operation, and the refrigerant itself is condensed into a high-pressure liquid refrigerant. This high-pressure liquid refrigerant is decompressed by the decompression devices 6a and 6b to become a low-pressure gas-liquid mixed refrigerant,
It flows into the non-use side heat exchanger 5, takes heat from the atmosphere or heat source water, evaporates, and returns to the first and second compressors 1 and 2 via the four-way switching valve 4 and the accumulator 8.

Next, the starting control device 20 for the first and second compressors 1 and 2 will be described with reference to the flow chart shown in FIG.
The starting method by will be described. When the operation is started, the second compressor 2 is started at the starting frequency in step S1, and the process proceeds to step 2. In step S2, the first timer means 12 for starting timekeeping when the second compressor 2 is started up.
It is determined whether or not the integrated time T _{1 due to} is greater than or equal to the activation delay time t ₁ . The start-up delay time t ₁ is set to about several seconds in order to reduce the rush current at the start-up. When the integrated time T ₁ becomes the start-up delay time t ₁ or more, the process proceeds to step S3 to start the first compressor 1. Let In step S4, the integrated time T ₁ is determined whether the startup control time t ₂ or more, and terminates the start control proceeds to step S5 if elapsed activation control time t _2.

[0006]

The conventional air conditioner is configured as described above, and since the first compressor 1 is started after a lapse of a fixed time after the second compressor 2 is started, When the refrigerant liquid is stored in each of the compressors 1 and 2 before starting, a rapid foaming phenomenon occurs. Since the second compressor 2 is started at a low speed by the inverter 10, a load applied to a sliding portion such as a bearing is small, but since the first compressor 1 is directly started by a commercial power source, it is frozen due to a foaming phenomenon. There was a problem that the function of the refrigeration cycle device could not be exerted due to insufficient supply of machine oil and seizure of sliding parts.

The present invention has been made to solve the above-mentioned problems, and even if the refrigerant liquid is stored in the compressor, it can be started without causing seizure of the sliding portion. The object is to obtain a refrigeration cycle device that can be used.

[0008]

A refrigeration cycle apparatus according to the present invention detects the discharge gas refrigerant pressure and temperature of a second compressor provided in parallel with the first compressor and driven by an inverter in the same cycle. Pressure and temperature detecting device, discharge gas refrigerant heating degree calculating means for calculating the discharge gas refrigerant heating degree by the discharge gas refrigerant pressure and the discharge gas refrigerant temperature detected by the both detecting devices, and the starting frequency via the inverter The second compressor is started with, and the calculated discharge gas refrigerant heating degree is compared with a preset superheat degree set value. When the discharge gas refrigerant heating degree is equal to or higher than the superheat degree set value, the second compressor is activated. And a start control device for controlling to drive the first compressor.

Further, when the discharge gas refrigerant heating degree is equal to or higher than the superheat degree set value and the integrated time from the start of the second compressor has passed a preset start delay time, Start the compressor of 1.

Further, the oil reservoirs of the first and second compressors are heated by a heating device, the second compressor is started at a starting frequency via the inverter, and the start is sent to the heating device. At the time of the first start after energization, the starting time t ₁ corresponding to the cumulative time t ₃ from when the heating device is energized and the second time
In comparison with the cumulative time T ₁ from the startup of the compressor, the first compressor is started when the cumulative time T ₁ is the startup delay time t ₁ or more.

[0011]

According to the present invention, the start control means starts the second compressor of the first and second compressors provided in parallel at a start frequency at which a load applied to a sliding portion such as a bearing is small.
When the degree of heating of the discharged gas refrigerant after startup becomes equal to or higher than the preset degree of superheat, the first compressor is started.

Further, the first compressor is started after the heating degree of the discharged gas refrigerant becomes equal to or higher than a preset superheat degree and a predetermined time has elapsed after the second compressor was started.

Further, the oil reservoirs of the first and second compressors provided in parallel are heated by the heating device and the second compressor is started at the starting frequency, and the integrated time from the start is The first compressor is started when the start delay time t ₁ according to the accumulated time from the time when the heating device is energized has elapsed.

[0014]

【Example】

Example 1. The block diagram of the refrigeration cycle apparatus according to the embodiment of the present invention shown in FIG. 1 will be described below. Figure 1
5, the same reference numerals as those in FIG. 5 indicate corresponding parts, and therefore their explanations are omitted. Reference numeral 15 is a pressure detecting means for detecting the discharge gas refrigerant pressure of the first and second compressors 1 and 2 connected in parallel, and 16 is the pressure detecting means of the first and second compressors 1 and 2 connected in parallel. Temperature detection means for detecting the discharge gas refrigerant temperature, 1
Reference numeral 3 is a discharge gas refrigerant superheat degree calculating means for calculating the superheat degree of the discharge gas refrigerant based on the discharge gas refrigerant pressure detected by the pressure detecting means 15 and the discharge gas refrigerant temperature detected by the temperature detecting means 16, and 14 is a first and a second. Is a startup control device for controlling startup of the compressor.

Next, the operation will be described. The operation of the refrigerating cycle during cooling and heating is the same as that of the conventional refrigerating cycle device described above, and therefore its explanation is omitted. Hereinafter, based on the flowchart shown in FIG. 2, the startup control device 13
The starting control of the first and second compressors 1 and 2 by the above will be described. First, the power supply (not shown) of the refrigeration cycle apparatus is turned on, and then the start switch (not shown) is turned on for the cooling and heating operation, the ON signal is input and the start control process is started, and at step S1 The inverter is controlled so as to output a starting frequency signal that sequentially increases to the frequency, the second compressor 2 is started by this starting frequency signal, and the time counting of the first timer means 12 is started, and the process proceeds to step S10. Step S10
Then, the discharge gas refrigerant pressure and the discharge gas refrigerant temperature detected by the pressure detecting means 15 and the temperature detecting means 16 are input, the saturation temperature is calculated based on the discharge gas refrigerant pressure input in step 11, and the input discharge is performed. The superheat degree SH of the discharged gas refrigerant is calculated by taking the temperature difference from the gas refrigerant temperature. Next, in step S12, a preset superheat degree set value ta (for example, 15 to 15) is determined in which there is no excess liquid refrigerant inside the first and second compressors 1 and 2 and it is determined that there is no liquid compression.
It is determined whether the calculated superheat degree SH of the discharged gas refrigerant is higher than 20 deg.), And if not, the process returns to step S10 to reheat the discharged gas refrigerant SH.
To judge. When the superheat degree SH of the discharged gas refrigerant is high, it is determined that there is no excess refrigerant liquid inside the first and second compressors 1 and 2, and the process proceeds to step S2. In step S2, the cumulative time T ₁ from the start of the second compressor 2 by the first timer means 12 is the first and second compressors 1 and 2.
A preset start delay time t ₁ (for example, 1 to 2 minutes) required for the refrigerant liquid to be substantially discharged from the tank and the distribution of the refrigerant in the accumulator 8 and the indoor / outdoor heat exchangers 7a, 7b, 5 and the like to be substantially uniform Whether or not the above is determined, and if the activation delay time t ₁ has elapsed, the process proceeds to step S3 and the first
The compressor 1 is started. If the integrated time T ₁ is shorter than the activation delay time t ₁ , the process returns to step S10.
Next, at step 4, the integrated time T ₁ is set to a predetermined start control time t ₂ (for example, 4 to 4) required for stabilizing the refrigerating machine oil concentrations in the first and second compressors 1 and 2 to an appropriate concentration.
5 minutes) or more, and if not, the first and second compressors 1 and 2 are held in the above-mentioned activated state. If the startup control time t ₂ has elapsed, the process proceeds to step S5 to end the startup control, release the hold of the startup state, and shift to the normal operation.

Example 2. 3 is a block diagram of a refrigeration cycle apparatus according to another embodiment of the present invention. In FIG.
The same reference numerals as those in FIG. 5 indicate corresponding parts, and thus the description thereof will be omitted. Reference numerals 17 and 18 denote heating devices that heat the oil reservoirs of the first and second compressors 1 and 2 to evaporate the refrigerant liquid dissolved in the refrigerating machine oil stored in the oil reservoirs. It is energized at the same time when the power source (not shown) of the device is turned on.
Reference numeral 19 is a second timer means for starting time counting when the power source (not shown) of the refrigeration cycle apparatus is turned on.

Next, the starting control of the first and second compressors 1 and 2 by the starting control device 20 will be described with reference to the flow chart shown in FIG. First, the power supply (not shown) of the refrigeration cycle apparatus is turned on. At the same time when this power is turned on, the heating devices 17 and 18 and the second timer means 19 are energized, the heating devices 17 and 18 heat the oil reservoirs of the first and second compressors 1 and 2, and the second The time is measured by the timer means after the power is turned on. Next, when the start switch (not shown) is turned on for the air conditioning operation, the ON signal is input to the start control device 20 to start the start control process, and in step S1, a start frequency signal that sequentially increases to a predetermined frequency is output. The inverter 11 is controlled so that the second compressor 2 is started by this starting frequency signal, and the second timer means 12 starts the time measurement, and the process proceeds to step S20. In step S20, it is determined whether the second compressor 2 is started up for the first time after the power is turned on,
In the case of the first activation, the process proceeds to step S21 and step S21.
In step 21, the post-power-on time t ₃ , which is the integrated time from the power-on time measured by the second timer means 19 to the first startup of the second compressor 2, is read, and the process proceeds to step S22. In step S22, after the power is turned on, which is read from the data of the start delay time t ₁ and the start control time t ₂ which are set in advance and written in the memory unit (not shown) and which change according to the time t ₃ after the power is turned on. Based on time t ₃ ,
At this time, proper start delay time t ₁ and start control time t ₂
Is read and the process proceeds to step S2. Incidentally, the startup delay time t ₁ and the heating device 17 after power on time t ₃ becomes large,
18 and the first by become second warming effect of the oil reservoir of the compressor 1 is sufficiently and after power time t ₃ the refrigerant liquid is a small amount that is the reservoir with the refrigerating machine oil in the oil reservoir The larger it is, the smaller it is set, and the start control time t ₂ is set to a time corresponding to the start delay time t ₁ . As a specific setting example, when the time t ₃ after the power is turned on is about 1 hour, the start delay time t ₁ is set to 4 to 5 minutes and the start control time t ₂ is set to 6 to 7 minutes. When t ₃ is about 4 hours, the activation delay time t ₁ is 1 to 2 minutes and the activation control time t ₂ is 3 to 4
When the power-on time t ₃ is 6 hours or more, the start delay time t ₁ is set to 0.5 to 1 minute and the start control time t ₂ is set to a relatively short time of ₂ to 3 minutes.

In step S2, if the number of startups after power-on is other than the first time, the process proceeds to step S23, and in step S23, the startup delay time t ₁ and the startup control time t ₂ in the case other than the first time are stored in the memory unit (not shown). No.) to read step S2. It should be noted that the startup delay time t ₁ and the startup control time t ₂ in cases other than the first time can be solved by solving the problems such as the storage of the refrigerant liquid in the oil reservoirs of the first and second compressors 1 and 2 at the first startup. Therefore, the start delay time t ₁ is set to 0.5 to 1 minute and the start control time t ₂ is set to ₂ to 3 minutes in a relatively short time. Whether the integrated time T ₁ from the start of the second compressor 2 integrated by the first timer means 12 in step S2 is equal to or longer than the startup delay time t ₁ read in step S22 or step S23 If the activation delay time t ₁ has elapsed, the routine proceeds to step S3, the first compressor 1 is activated, and the routine proceeds to step S4. In step S4, it is determined whether or not the integrated time T ₁ is equal to or longer than the startup control time t ₂ read in step S22 or step S23. If not, the first and second compressors 1 and 2 are set to the startup state. If the start control time t ₂ has elapsed, the process proceeds to step S5 to end the start control, release the hold of the start state, and shift to normal operation.

[0019]

As described above, according to the present invention, the discharge refrigerant pressure and the discharge refrigerant temperature of the first and second compressors provided in parallel are detected to calculate the superheat degree of the discharge gas refrigerant. , When the degree of superheat exceeds a preset degree of superheat
Since the compressor is configured to be started, an accident such as seizure of the compressor due to insufficient oil supply to the sliding portion due to a foaming phenomenon at the time of start can be prevented.

When the degree of superheat of the discharged gas refrigerant is equal to or higher than a predetermined value and the integrated time from the start of the second compressor is equal to or longer than a predetermined start delay time, the first compressor is used. Since it is configured to start, the first compressor is not started in the time zone in which the superheat degree is unstable due to the transient liquid back from the accumulator, so that the reliability is further improved.

Further, a start delay corresponding to an integrated time t ₃ from when the heating device for heating the oil reservoirs of the first and second compressors provided in parallel is energized to the start of the second compressor. Time t ₁
And the cumulative time T ₁ from the start of the second compressor are compared, and the _first compressor is started when the cumulative time T ₁ becomes equal to or longer than the startup delay time. The refrigerant liquid is less accumulated at the time of starting the compressor, the foaming phenomenon at the time of starting is alleviated, and accidents such as seizure of the compressor are prevented.

[Brief description of drawings]

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

FIG. 2 is a flow chart showing a start control processing means of the start control device in FIG.

FIG. 3 is a configuration diagram showing a refrigeration cycle apparatus according to another embodiment of the present invention.

FIG. 4 is a flowchart showing a startup control processing procedure of the startup control device in FIG.

FIG. 5 is a configuration diagram showing a conventional refrigeration cycle apparatus.

FIG. 6 is a flowchart showing a startup control processing procedure of the startup control device shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st compressor 2 2nd compressor 11 Inverter 12 1st timer means 13 Discharge gas refrigerant superheat degree calculation means 14 Startup control means 15 Pressure detection means 16 Temperature detection means

[Procedure amendment]

[Submission date] April 2, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 1

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 2

[Correction method] Change

[Correction content]

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

[0008]

A refrigeration cycle apparatus according to the present invention detects the discharge gas refrigerant pressure and temperature of a second compressor provided in parallel with the first compressor and driven by an inverter in the same cycle. and pressure and temperature sensing device for a discharge gas refrigerant superheat calculation means for calculating a discharged gas refrigerant superheat by the detected discharged gas refrigerant pressure and the discharged gas refrigerant temperature at the both detection devices, start frequency through the inverter in addition to activating the second compressor, comparing the preset degree of superheat setpoint and the discharge gas refrigerant superheat that is the arithmetic, the first when the discharge gas refrigerant superheat is higher superheat setpoint And a start control device for controlling to drive the first compressor.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

Further, it becomes superheat of the discharge gas refrigerant preset degree of superheat above, and starts the first compressor after the second compressor after starting a predetermined time.

Claims (3)

[Claims] 1. A first compressor, a second compressor provided in parallel with the first compressor in the same refrigeration cycle and driven by an inverter, and first and second devices provided in parallel. A pressure detector and a temperature detector for respectively detecting the discharge gas refrigerant pressure and the discharge gas refrigerant temperature of the second compressor;
The discharge gas refrigerant heating degree calculating means for calculating the discharge gas refrigerant heating degree based on the discharge gas refrigerant pressure and the discharge gas refrigerant temperature detected by the both detectors, and the second compressor at the starting frequency via the inverter. Control is performed so that the first compressor is started when the calculated discharge gas refrigerant superheat degree is compared with a preset superheat degree set value, and the discharge gas refrigerant superheat degree is equal to or higher than the superheat set value. A refrigeration cycle apparatus, comprising: 2. A first compressor, a second compressor provided in parallel with the first compressor in the same refrigeration cycle and driven by an inverter, and the first and the second compressor provided in parallel. A pressure detector and a temperature detector for respectively detecting the discharge gas refrigerant pressure and the discharge gas refrigerant temperature of the second compressor;
Discharge gas refrigerant superheat degree calculating means for calculating a discharge gas refrigerant superheat degree based on the detected discharge gas refrigerant pressure and discharge gas refrigerant temperature, and starting the second compressor at a starting frequency via the inverter and The calculated discharge gas refrigerant superheat degree is compared with a preset superheat degree setting value, and the discharge gas refrigerant superheat degree is equal to or higher than the superheat degree set value, and the accumulated time from the start of the second compressor. A refrigeration cycle apparatus comprising: a startup control device that controls to start the first compressor when a preset startup delay time has elapsed. 3. A first compressor, a second compressor provided in parallel in the same refrigeration cycle as the first compressor and driven by an inverter, and the first and second compressors. A heating device that heats the oil sump and the second compressor is started at a starting frequency via the inverter, and when the starting is the first start after the heating device is energized, from the time when the heating device is energized. Start delay time t ₁ according to the cumulative time t ₃ of
And the cumulative time T ₁ from the startup of the second compressor are compared, and when the cumulative time T ₁ is the startup delay time t ₁ or more, the startup is controlled to start the first compressor. A refrigeration cycle apparatus comprising a control device.