WO2023040210A1

WO2023040210A1 - Refrigeration system

Info

Publication number: WO2023040210A1
Application number: PCT/CN2022/079368
Authority: WO
Inventors: 高斌; 高强
Original assignee: 广东美芝制冷设备有限公司; 广东美芝精密制造有限公司
Priority date: 2021-09-18
Filing date: 2022-03-04
Publication date: 2023-03-23
Also published as: CN113758035A

Abstract

A refrigeration system comprises a compressor assembly, a high-pressure pipeline (200) and a low-pressure pipeline (300). The compressor assembly comprises multiple compressors connected in parallel. The high-pressure pipeline (200) is connected to an exhaust end of the compressor assembly, and a first heat exchanger (210) is provided in the high-pressure pipeline (200). The low-pressure pipeline (300) is connected to an air intake end of the compressor assembly, and a second heat exchanger (310) is provided in the low-pressure pipeline (300). A throttling component (400) is disposed between the low-pressure pipeline (300) and the high-pressure pipeline (200). At least one compressor is a first compressor (100), the first compressor (100) being provided with a first air inlet pipe (110) and a first exhaust pipe (120). At least one of the first air inlet pipe (110) and the first exhaust pipe (120) is provided with a first control valve (130). The first air inlet pipe (110) and the first exhaust pipe (120) are in communication via a first pressure relief valve (140).

Description

a refrigeration system

Cross References to Related Applications

This application claims the priority of the Chinese patent application No. 202111097440.X, filed on September 18, 2021, entitled "A Refrigeration System", the entire contents of which are incorporated by reference in this application.

technical field

The invention relates to the technical field of refrigeration, in particular to a refrigeration system.

Background technique

In the related art, because the rotary compressor has many advantages such as small size, low cost, and high reliability, there is a type of refrigeration system that uses multiple rotary compressors to work in parallel to meet the requirement of refrigeration capacity. This type of refrigeration system operates at full load for multiple rotary compressors at the beginning of startup to quickly reach the set temperature condition. When the system is running stably, some rotary compressors can run to meet the requirements, and some rotary compressors can be controlled. Shutdown to save energy, with better economy, when the load increases, the shutdown rotary compressor restarts. Due to its design characteristics, the rotary compressor requires that the suction and discharge side pressures reach a balanced state when starting. Generally, the set pressure difference is less than 0.1MPa to ensure the reliability of starting. However, there is still a large pressure difference between the high and low pressure pipelines of the refrigeration system, which may easily cause the rotary compressor to fail to restart. Repeated restart failures will cause the motor to heat up rapidly, and there is even a risk of burning the motor.

Contents of the invention

The present invention aims to solve at least one of the technical problems existing in the prior art. For this reason, the present invention proposes a refrigeration system that can meet the restart conditions of the rotary compressor and avoid the risk of restart failure.

A refrigeration system according to an embodiment of the present invention includes a compressor assembly, a high-pressure pipeline, and a low-pressure pipeline, the compressor assembly includes a plurality of compressors connected in parallel, and the high-pressure pipeline is connected to the exhaust At the gas end, the high-pressure pipeline is provided with a first heat exchanger, the low-pressure pipeline is connected to the intake end of the compressor assembly, the low-pressure pipeline is provided with a second heat exchanger, and the low-pressure pipeline is A throttling component is arranged between the pipeline and the high-pressure pipeline; wherein, at least one of the compressors is a first compressor, and the first compressor has a first inlet pipe and a first exhaust pipe, and the At least one of the first intake pipe and the first exhaust pipe is provided with a first control valve, and the first air intake pipe and the first exhaust pipe are communicated through a first pressure relief valve.

The refrigerating system according to the embodiment of the present invention has at least the following beneficial effects: when the load of the refrigerating system is low, the first compressor is stopped to reduce energy consumption. Since at least one of the first intake pipe and the first discharge pipe of the first compressor is provided with a first control valve, the first compressor can be disconnected from the high-pressure pipeline and/or the low-pressure pipeline by using the first control valve, and The first pressure relief valve can quickly eliminate the pressure difference between the first intake pipe and the first exhaust pipe, meet the conditions for the restart of the first compressor, prevent the failure of the first compressor to restart, and eliminate the failure of the first compressor to restart The resulting rapid heating of the motor or even the risk of motor burnout improves the operation stability of the refrigeration system.

According to some embodiments of the present invention, the first pressure relief valve has an inlet M and an outlet N, the inlet M communicates with the first exhaust pipe through a pipeline, and the outlet N communicates with the first intake pipe through a pipeline .

According to some embodiments of the present invention, the first pressure relief valve has an inlet M and an outlet N, the first pressure relief valve is disposed inside the first compressor, and the inlet M communicates with the first row The air pipe, the outlet N communicates with the first air intake pipe.

According to some embodiments of the present invention, the opening pressure difference of the first pressure relief valve is set to Pr, which satisfies Pr≤0.8MPa.

According to some embodiments of the present invention, the first pressure relief valve is electrically connected to a controller, the controller is electrically connected to the first compressor, and the controller controls the opening of the first pressure relief valve. close.

According to some embodiments of the present invention, the plurality of compressors are all the first compressors.

According to some embodiments of the present invention, the first control valve is a one-way valve.

According to some embodiments of the present invention, the first control valve is an electromagnetic cut-off valve.

According to some embodiments of the present invention, the first intake pipe is provided with the first control valve, and the first exhaust pipe is provided with the first control valve.

According to some embodiments of the present invention, the first compressor is connected with an accumulator, the first air intake pipe is arranged at the inlet of the liquid accumulator, and the first inlet pipe arranged on the first air inlet pipe The control valve is located in the accumulator, and the first control valve arranged on the first discharge pipe is located in the first compressor.

Additional aspects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Description of drawings

Additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments when taken in conjunction with the following drawings, in which:

Fig. 1 is the structural representation of the refrigeration system of some embodiments of the present invention;

Fig. 2 is a schematic structural view of the first compressor in the refrigeration system of Fig. 1;

Figure 3 is a cross-sectional view of the first pressure relief valve in some embodiments of the present invention;

Fig. 4 is a schematic structural diagram of a refrigeration system according to another embodiment of the present invention;

Fig. 5 is a schematic structural diagram of a refrigeration system according to another embodiment of the present invention;

Fig. 6 is a schematic structural view of the first compressor in the refrigeration system of Fig. 5;

Fig. 7 is a partially enlarged view at G of Fig. 6;

Figure 8 is a cross-sectional view of a check valve in some embodiments of the present invention;

Fig. 9 is a schematic structural diagram of a refrigeration system according to another embodiment of the present invention;

Fig. 10 is a schematic structural diagram of a refrigeration system according to another embodiment of the present invention; and

Fig. 11 is a schematic structural diagram of the first compressor in the refrigeration system of Fig. 10 .

The attached reference numbers are as follows:

The first compressor 100, the first intake pipe 110, the first exhaust pipe 120, the first control valve 130, the housing 131, the first pressure relief valve 140, the valve body 141, and the accumulator 150;

High pressure pipeline 200, first heat exchanger 210;

Low pressure pipeline 300, second heat exchanger 310;

Throttle member 400.

Detailed ways

Embodiments of the present invention are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference numerals designate the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the figures are exemplary only for explaining the present invention and should not be construed as limiting the present invention.

In the description of the present invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc. indicated orientations or positional relationships are based on the orientations or positional relationships shown in the drawings, and are only In order to facilitate the description of the present invention and simplify the description, it does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention.

In the description of the present invention, if the first and the second are described only for the purpose of distinguishing technical features, it cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or implicitly indicating The sequence of the indicated technical features.

In the description of the present invention, unless otherwise clearly defined, words such as setting, installation, and connection should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

Rotary compressor is a type of compressor widely used in refrigeration equipment at present. The motor of the rotary compressor does not need to convert the rotary motion of the rotor into the reciprocating motion of the piston, but directly drives the rotary piston to rotate to complete the cooling of the refrigerant. of compression. Rotary compressors are more suitable for small air conditioners, especially widely used in household air conditioners.

The main advantages of rotary compressors are: due to the rotary motion of the piston, the compression work is smooth, stable and balanced. In addition, the rotary air compressor has no clearance volume and no interference from re-expansion gas, so it has high compression efficiency, few parts, small volume, light weight, good balance performance, low noise, complete protection measures and low power consumption, etc. advantage. The disadvantage is that the rotary compressor has higher requirements on material, machining accuracy, heat treatment, assembly process and lubrication system. With the advancement of technology, rotary compressors have obvious advantages over other types of air compressors, and are widely used in household air conditioners and refrigerators. From the perspective of development trends, rotary air compressors will become market leading products.

In related technologies, there is a type of large-scale refrigeration system that uses multiple rotary compressors to work in parallel to meet the demand for large-scale changes in refrigeration load. This type of refrigeration system operates with full load of multiple rotary compressors at the beginning of startup to quickly reach the set temperature condition. When the system is running stably, some rotary compressors can run to meet the cooling load and control the rotation of the other part. The compressor is shut down to save energy, which is more economical. When the load on the refrigeration system increases, the stopped rotary compressor restarts to provide sufficient cooling capacity. Due to its design characteristics, the rotary compressor requires that the suction and discharge side pressures reach a balanced state when starting, and the pressure difference is less than 0.1MPa, so as to ensure the reliability of starting. However, there is still a large pressure difference between the high and low pressure pipelines of the refrigeration system, which is likely to cause the rotary compressor to fail to restart. Repeated restart failures will cause the motor of the rotary compressor to heat up rapidly, and there is even a risk of burning the motor, seriously affecting use.

Referring to Figures 1 to 6, an embodiment of the present invention proposes a refrigeration system, including a compressor assembly composed of multiple parallel compressors. It can be understood that the compressors here are mainly rotary compressors, and can also be Extended application to other types of compressors, balancing the pressure on the intake and discharge sides, is beneficial for all types of compressor start-ups. In the following, the compressor assembly adopts multiple parallel rotary compressors as an example for description. In addition, a plurality of rotary compressors of the compressor assembly can be stopped, and the rotary compressor that can be stopped is defined as the first compressor 100. As shown in FIG. 1, the compressor assembly includes a plurality of parallel first compressors 100. During the operation of the refrigeration system, the start and stop of multiple first compressors 100 are controlled according to the refrigeration load, which can not only meet the demand for refrigeration capacity, but also reduce energy consumption, and has better economy.

The refrigeration system also includes a high-pressure pipeline 200 and a low-pressure pipeline 300. The exhaust end of the compressor assembly is connected to the high-pressure pipeline 200, and the intake end of the compressor assembly is connected to the low-pressure pipeline 300, that is, multiple parallel first compressors The exhaust of 100 is input into the high-pressure pipeline 200, the intake air of multiple parallel first compressors 100 comes from the low-pressure pipeline 300, the high-pressure pipeline 200 has a first heat exchanger 210, and the low-pressure pipeline 300 With the second heat exchanger 310 , the throttling component 400 is disposed between the low-pressure pipeline 300 and the high-pressure pipeline 200 , that is, the throttling component 400 is located between the first heat exchanger 210 and the second heat exchanger 310 . When the refrigeration system is running, the compressor assembly outputs high-temperature, high-pressure refrigerant gas. The high-temperature, high-pressure refrigerant gas cools down through the first heat exchanger 210, and then outputs refrigerant liquid through the throttling effect of the throttling component 400. The second heat exchanger 310 is evaporated into a low-temperature, low-pressure refrigerant gas, and at the same time, the second heat exchanger 310 is used to produce cold air to meet the demand for cooling capacity. The low-temperature, low-pressure refrigerant gas is transported from the low-pressure pipeline 300 back to the compressor assembly. Once the refrigerant cycle is completed, the refrigerant circulates continuously, and the refrigeration system can continuously provide cooling capacity.

After the operation of the refrigeration system enters a stable state, the demand for cooling capacity decreases, and some of the first compressors 100 are shut down. Referring to Fig. 2, the intake end of the first compressor 100 is provided with a first intake pipe 110, and the exhaust end is provided with a first exhaust pipe 120, that is, a plurality of parallel first compressors 100 all pass through the first intake pipe. 110 communicates with the low-pressure pipeline 300, and communicates with the high-pressure pipeline 200 through the first exhaust pipe 120. Both the first intake pipe 110 and the first exhaust pipe 120 are provided with a first control valve 130, and the first compressor 100 is shut down. state, the first control valve 130 can cut off the first intake pipe 110 and the low-pressure pipe 300, and at the same time cut off the first exhaust pipe 120 and the high-pressure pipe 200, the first compressor 100 is independent of the pipeline of the refrigeration system, and A first pressure relief valve 140 is provided between the first intake pipe 110 and the first exhaust pipe 120, and the first pressure relief valve 140 can connect the intake end and the exhaust end of the first compressor 100 to eliminate the pressure difference . It can be understood that the first pressure relief valve 140 is located between the first control valve 130 on the first intake pipe 110 and the first control valve 130 on the first exhaust pipe 120 , and is not affected by the high-pressure pipeline 200 during pressure relief. and the impact of the low pressure line 300.

When the load of the refrigeration system is low, part of the first compressors 100 or all of the first compressors 100 are stopped to reduce energy consumption, and the first compressor 100 is isolated by the first control valve 130, and then quickly Eliminating the pressure difference between the intake end and the exhaust end satisfies the condition for restarting the first compressor 100 . When the load changes, some of the first compressors 100 or all of the first compressors 100 are restarted, which solves the problem of the failure of the first compressor 100 to restart, and eliminates the risk of rapid heating of the motor or even motor burnout caused by the failure of the first compressor 100 to restart , improve the stability of the refrigeration system.

It can be understood that the intake end of the first compressor 100 may be provided with a first intake pipe 110, and the discharge end may be provided with a first exhaust pipe 120, that is, a plurality of parallel first compressors 100 all pass through the first compressor 100. An intake pipe 110 communicates with the low-pressure pipeline 300 and communicates with the high-pressure pipeline 200 through the first exhaust pipe 120 . The first air intake pipe 110 is provided with a first control valve 130 . When the first compressor 100 is in the shutdown state, the first air intake pipe 110 and the low-pressure pipeline 300 can be cut off by the first control valve 130 , the first compressor 100 is only connected to the high-pressure pipeline 200 , and the first pressure relief valve 140 is used to conduct The inlet end and the exhaust end of the first compressor 100 are both at a pressure close to the high-pressure pipeline 200 , which can also eliminate the pressure difference.

Alternatively, the intake end of the first compressor 100 is provided with a first intake pipe 110, and the exhaust end is provided with a first exhaust pipe 120, that is, a plurality of parallel first compressors 100 all pass through the first intake pipe 110. It communicates with the low-pressure pipeline 300 and communicates with the high-pressure pipeline 200 through the first exhaust pipe 120 , and the first exhaust pipe 120 is provided with a first control valve 130 . When the first compressor 100 is in the shutdown state, the first exhaust pipe 120 and the high-pressure pipeline 200 can be cut off by the first control valve 130, and the first compressor 100 is only connected to the low-pressure pipeline 300, and the first pressure relief valve 140 is used to guide Through the intake end and the exhaust end of the first compressor 100, the pressure of the intake end and the exhaust end is close to the low-pressure pipeline 300, which can also eliminate the pressure difference.

It can be understood that only some of the plurality of compressors of the compression assembly can be stopped, such as one or two. Taking the refrigeration system with a first compressor 100 as an example, the first compressor 100 communicates with the low-pressure pipeline 300 through the first inlet pipe 110, and at the same time communicates with the high-pressure pipeline 200 through the first exhaust pipe 120, and the high-pressure pipeline 200 has The first heat exchanger 210 has the second heat exchanger 310 on the low-pressure pipeline 300, and the throttling component 400 is arranged between the low-pressure pipeline 300 and the high-pressure pipeline 200, that is, the throttling component 400 is located in the first heat exchanger 210 and the second heat exchanger 310; the first intake pipe 110 and the first exhaust pipe 120 are provided with a first control valve 130, and the first compressor 100 can be controlled by the first control valve 130 when the first compressor 100 is stopped. Cut off the first intake pipe 110 and the low-pressure pipeline 300, the first exhaust pipe 120 and the high-pressure pipeline 200 can be cut off through the first control valve 130, the first compressor 100 is independent of the pipeline of the refrigeration system, and the first intake pipe A first pressure relief valve 140 is provided between the first exhaust pipe 110 and the first exhaust pipe 120. The first pressure relief valve 140 can connect the intake end and the exhaust end of the first compressor 100 to eliminate the pressure difference.

When the load of the refrigeration system is low, only the first compressor 100 is stopped to reduce energy consumption; when the load changes, the first compressor 100 is restarted, which solves the problem of restart failure of the first compressor 100 and eliminates the need for the first compressor 100 The risk of rapid motor heating or even motor burnout caused by restart failure improves the operation stability of the refrigeration system.

It can be understood that, as shown in FIG. 3 , the first pressure relief valve 140 includes a valve body 141, and a through valve cavity is arranged in the valve body 141, and a valve plate F and a spring E are arranged in the valve cavity. The inlet M of the valve 140 is connected to the exhaust end of the first compressor 100, and the outlet N is connected to the inlet end of the first compressor 100. Under normal conditions, the spring E pushes the valve plate F, and the valve plate F leaves the valve port, and the first pressure release Valve 140 is in an open state. When the first compressor 100 is running, the pressure difference between the inlet M and the outlet N acts on the valve plate F with a pressure force greater than the elastic force of the spring E, and the valve plate F closes the first pressure relief valve 140 . When the first compressor 100 stops, the pressure at the exhaust end and the intake end tends to be balanced, and the pressure difference between the inlet M and the outlet N decreases. When the pressure difference acting on the valve plate F is smaller than the spring force of the spring E, The valve plate F is pushed open by the spring force, and the first pressure relief valve 140 is opened, and the exhaust end and the intake end of the first compressor 100 are quickly released through the first pressure relief valve 1407 to achieve pressure balance, satisfying the requirements of the first compressor. 100 restart conditions.

It can be understood that the opening pressure difference of the first pressure relief valve 140 is usually defined as Pr, and it is required that Pr≤0.8Mpa. When the pressure difference between the inlet M and the outlet N≤0.8Mpa, the pressure difference force acting on the valve plate F The spring force of the spring E is smaller than that of the spring E, the valve plate F is pushed open by the spring force, and the first pressure relief valve 140 is opened, and the exhaust end and the intake end of the first compressor 100 are quickly released through the first pressure relief valve 1407 to achieve pressure balance , meeting the condition for restarting the first compressor 100 .

2, it can be understood that the first pressure relief valve 140 can be arranged outside the first compressor 100, the inlet M of the first pressure relief valve 140 communicates with the first exhaust pipe 120 through a pipeline, and the pipeline is located at the first Between a control valve 130 and the exhaust end of the first compressor 100, the outlet N of the first pressure relief valve 140 is connected to the first intake pipe 110 through a pipeline, and the pipeline is located between the first control valve 130 and the first compressor 100 Between the intake ends, it is easy to assemble and has a simple structure.

5 to 7, it can be understood that the first pressure relief valve 140 can also be arranged inside the first compressor 100, the first compressor 100 has an accumulator 150, and the accumulator 150 is arranged in the first On the intake pipe 110, the inlet M of the first pressure relief valve 140 communicates with the first exhaust pipe 120 through the inner space of the first compressor 100, and the outlet N of the first pressure relief valve 140 and the first intake pipe 110 are located at the first compression The ports in machine 100 are directly connected. The first pressure relief valve 140 is placed inside the first compressor 100, and the structure of the first compressor 100 is more compact, which is beneficial to the layout of the refrigeration system.

Referring to FIG. 4 , it can be understood that the first pressure relief valve 140 can also be controlled by a controller, and the controller is electrically connected to the first compressor 100 at the same time. After the first compressor 100 stops, the controller controls the first pressure relief valve 140. The valve 140 is opened for pressure relief, and when the first compressor 100 is started, the first pressure relief valve 140 is automatically closed; or the first pressure relief valve 140 is an externally controlled valve, and the first pressure relief valve is controlled by an external signal The switch of 140, such as controlling the first pressure relief valve 140 through a relay, after the first compressor 100 stops, after the set time, the first pressure relief valve 140 automatically opens to release pressure, and when the first compressor 100 starts, The first pressure relief valve 140 is automatically closed.

Referring to Fig. 4 and Fig. 8, it can be understood that the first control valve 130 can be a one-way valve, and the one-way valve includes a housing 131, and a power mechanism such as a spring for automatically pushing the valve plate D to close the valve port is provided in the housing 131 C. When no refrigerant flows from the inlet A of the check valve to the outlet B, the spring C pushes the valve piece D to close the check valve; when there is fluid flowing from the inlet A of the check valve to the outlet B, the fluid overcomes the spring force of the spring C , open the one-way valve. Figure 8 shows only a common one-way valve structure, and all one-way valves with automatic closing function can be applied to the embodiment of the present invention.

9, it can be understood that the first control valve 130 can also be an electromagnetic cut-off valve. After the first compressor 100 stops, the electromagnetic cut-off valve will automatically close to isolate the first compressor 100 and prevent the high-pressure pipeline 200 from being connected to the low-pressure pipeline. The pressure difference in the pipeline 300 affects the restart of the first compressor 100; when the first compressor 100 restarts, the electromagnetic shut-off valve is automatically opened.

Referring to FIG. 10 and FIG. 11 , it can be understood that the electromagnetic cut-off valve can also be arranged inside the first compressor 100 , and the two electromagnetic cut-off valves and the first pressure relief valve 140 are both located inside the first compressor 100 . The electromagnetic shut-off valve connected to the first air intake pipe 110 is arranged inside the accumulator 150, and the electromagnetic shut-off valve connected to the first exhaust pipe 120 is located inside the first compressor 100. The structure of the first compressor 100 is more compact and has Conducive to the layout of the refrigeration system.

The embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned embodiments. Within the scope of knowledge of those of ordinary skill in the art, various modifications can be made without departing from the gist of the present invention. kind of change.

Claims

A refrigeration system comprising:

a compressor assembly comprising a plurality of compressors connected in parallel;

a high-pressure pipeline connected to the exhaust end of the compressor assembly, and a first heat exchanger is arranged in the high-pressure pipeline; and

a low-pressure pipeline connected to the intake end of the compressor assembly, a second heat exchanger is arranged in the low-pressure pipeline, and a throttling component is arranged between the low-pressure pipeline and the high-pressure pipeline;

Wherein, at least one of the compressors is a first compressor, and the first compressor has a first intake pipe and a first exhaust pipe, and at least one of the first air intake pipe and the first exhaust pipe A first control valve is provided, and the first air intake pipe communicates with the first exhaust pipe through a first pressure relief valve.
The refrigeration system according to claim 1, wherein the first pressure relief valve has an inlet and an outlet, the inlet communicates with the first exhaust pipe through a pipe, and the outlet communicates with the first intake pipe through a pipe .
The refrigeration system according to claim 1, wherein the first pressure relief valve has an inlet and an outlet, the first pressure relief valve is disposed inside the first compressor, and the inlet communicates with the first An exhaust pipe, the outlet communicates with the first air intake pipe.
The refrigeration system according to claim 2 or 3, wherein the opening pressure difference of the first pressure relief valve is set as Pr, satisfying Pr≤0.8MPa.
The refrigeration system according to claim 2 or 3, wherein the first pressure relief valve is electrically connected to a controller, the controller is electrically connected to the first compressor, and the controller controls the first Opening and closing of a pressure relief valve.
The refrigeration system according to claim 1, wherein a plurality of said compressors are all said first compressors.
The refrigeration system according to claim 1, wherein said first control valve is a one-way valve.
The refrigeration system according to claim 1, wherein the first control valve is an electromagnetic stop valve.
The refrigeration system according to claim 7 or 8, wherein the first intake pipe is provided with the first control valve, and the first discharge pipe is provided with the first control valve.
The refrigeration system according to claim 9, wherein the first compressor is connected to an accumulator, the first air inlet pipe is arranged at the inlet of the liquid accumulator, and the air inlet pipe arranged on the first air inlet pipe The first control valve is located in the accumulator, and the first control valve provided on the first exhaust pipe is located in the first compressor.