JPH0587416A - Cooling system - Google Patents

Abstract

PURPOSE:To improve the efficiency of a system and to reduce the size and the weight of a system by reducing the drive force of a motor and simplifying a circuit. CONSTITUTION:A turbine 13 monoaxially coupled to a compressor 10 is disposed to a bypass circuit 2. In the feedback of a refrigerant (p), a power is recovered by causing the refrigerant (p) to effect an expansion work and the temperature of the refrigerant (p) itself is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling system used for an air conditioner for an aircraft, an air conditioner for an automobile, an air conditioner for a room, and the like.

[0002]

2. Description of the Related Art FIG. 2 shows an example of a conventional cooling system used for air conditioning. This cooling system is composed of a vapor cycle unit 1 and a bypass circuit 2. The vapor cycle unit 1 connects between the evaporator 3 and the condenser 4 by a refrigerant circulation circuit 5 filled with a refrigerant p such as Freon gas, and the amount of heat received by the refrigerant p in the evaporator 3 from the air q to be cooled is In the condenser 4, the refrigerant p is discharged to the outside air r. Therefore, a filter 6 for purifying the refrigerant p in the refrigerant circulation circuit 5 on the outlet side of the condenser 4 and the inlet side of the evaporator 3, a receiver 7 for storing the refrigerant p, and an adiabatic expansion of the transferred refrigerant p. An expansion valve 8 is provided, and a temperature sensing unit 9 for detecting the temperature of the refrigerant p is provided in the refrigerant circulation circuit 5 at the outlet side of the evaporator 3 and the inlet side of the condenser 4, and the transferred refrigerant p is adiabatically compressed. A radial type compressor 10 is provided. Further, a motor M ₁ is arranged to drive the compressor 10. On the other hand, the bypass circuit 2
Is a circuit for transferring a part of the refrigerant p flowing out from the outlet side of the compressor 10 to the inlet side of the compressor 10, and is provided with a bypass valve 11a controlled by a detection signal a from the temperature sensing unit 9. is doing.

Next, the operation of this cooling system will be described. The refrigerant p is first compressed by the compressor 10 and flows into the condenser 4. Here, it is cooled and liquefied by exchanging heat with the outside air r. Then, after removing water and foreign substances from the liquefied refrigerant p by the filter 6,
It flows into the receiver 7. The receiver 7 stores the liquefied refrigerant p. Then, the refrigerant p in the receiver 7
Is transferred to the expansion valve 8 and expanded by the expansion valve 8, whereby the refrigerant p enters a low-temperature gas-liquid mixed state and flows into the evaporator 3. In the evaporator 3, heat exchange with the air q is performed to vaporize the liquid phase of the refrigerant p, and at this time, the air q is cooled and sent to a cooling room or the like. The temperature sensing unit 9 is for preventing the refrigerant p from flowing into the compressor 10 in a liquefied state, and detects the temperature of the refrigerant p that takes heat from the air q and flows out to the outlet side of the evaporator 3. By adjusting the opening degree of the expansion valve 8 in accordance with the detection signal a, the refrigerant p is made to be in a substantially completely vaporized state and flow into the compressor 10. If the set temperature is constant, the expansion valve 8 is adjusted to the opening increase side as the amount of air q increases (that is, the load increases), and to the opening decrease side as the amount decreases. Become. Then, the refrigerant p compressed by the compressor 10 releases its heat by heat exchange with the outside air r when flowing into the condenser 4, and is cooled and liquefied again. By repeating such a cycle of the refrigerant p, this cooling system can perform the function of pumping out heat from the evaporator 3 and discharging it from the condenser 4.

By the way, the compressor 10 has a problem that, as a characteristic of the non-volume type, when the inflowing refrigerant p is less than a required amount, surging causes a failure. Therefore, when the expansion valve 8 is throttled, the compressor 10 is opened by opening the bypass valve 11a provided in the bypass circuit 2.
A part of the refrigerant p flowing out from the evaporator 3 is replenished with the refrigerant p flowing out from the evaporator 3 to ensure a minimum flow rate, and the refrigerant p is made to flow into the compressor 10.

[0005]

However, when the refrigerant p is returned from the outlet side to the inlet side of the compressor 10 through the bypass circuit 2, the refrigerant p is returned to the compressor 1 again.
It will have to be compressed at zero. Therefore, the motor M
A part of the compression work performed by the compressor 10 through the driving of _{No. 1} is wasted, and the efficiency of the system is reduced. In addition, although the inlet temperature of the compressor 10 (that is, the temperature of the temperature sensing unit 9) needs to be always maintained at a predetermined temperature, the compressed refrigerant p flows from the outlet side of the compressor 10 to the inlet side. Inflow causes rise in inlet temperature. From this, conventionally, a bypass temperature adjusting circuit 12 having a bypass valve 11b is attached as shown in FIG. 2, and a part of the low temperature refrigerant p stored in the receiver 7 is passed through the bypass temperature adjusting circuit 12 to the inlet of the compressor 10. It is mixed with the refrigerant p on the side to offset the temperature change. For this reason, the number of parts increases, and there is a drawback that the cost and the weight increase. Further, the radial compressor has a feature that it is smaller and lighter than the displacement type compressor, but since the flow rate becomes smaller in a small capacity system, the radial compressor cannot be applied.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a cooling system capable of improving the efficiency of the system and reducing the size and weight.

[0007]

The present invention adopts the following constitution in order to achieve the above object.

That is, the cooling system according to the present invention is
A refrigerant circulation circuit is connected between the evaporator and the condenser, and an expansion valve is arranged between the condenser outlet side and the evaporator inlet side, and a non-volume type is provided between the evaporator outlet side and the condenser inlet side. A vapor cycle section is formed by disposing a compressor, and further, in a cooling system in which the compressor outlet side and the compressor inlet side are connected by a bypass circuit, a fluid passing through the bypass circuit is coaxial with the compressor. It is characterized in that a driven turbine is provided.

[0009]

With such a configuration, when the turbine is provided, when the refrigerant compressed by the compressor passes through the turbine, expansion work is performed on the turbine,
The energy of the refrigerant is converted into mechanical energy and transmitted to the compressor arranged coaxially with the turbine. Therefore, the driving force of the motor can be reduced by the amount of mechanical energy acquired by the turbine, and the system efficiency can be improved. Further, the temperature of the refrigerant is lower than the temperature at the compressor outlet side by performing expansion work on the turbine, so that it does not cause a large temperature rise at the compressor inlet side, and the bypass temperature adjustment circuit is used. It can be unnecessary.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. The same parts as those in FIG. 2 are designated by the same reference numerals and the description thereof will be omitted.

This cooling system has the basic structure shown in FIG. 2, and is provided with a turbine 13 driven by a fluid passing through a bypass valve 11a in the bypass circuit 2. The turbine 13 is uniaxially connected to the compressor 10, and a motor M ₂ is arranged to drive the compressor 10.

When such a structure is adopted, when a part of the refrigerant p compressed by the compressor 10 passes through the turbine 13, expansion work is performed on the turbine 13,
The energy of the refrigerant p is converted into mechanical energy,
It is transmitted to the turbine 13 and the compressor 10 arranged on a single axis. In other words, some of the compression work done by compressor 10 is recovered by turbine 13. Therefore, the driving force of the motor M ₂ is equal to that of the turbine 1
The driving force of the motor M ₁ can be made smaller than the driving force of the motor M _{1 by} the amount of mechanical energy acquired by the motor 3, and the system efficiency can be certainly improved as compared with the conventional case. Also, the refrigerant p
The temperature of is lower than the temperature at the outlet side of the compressor 10 due to the expansion work performed on the turbine 13, so that the temperature does not greatly increase at the inlet side of the compressor 10. Therefore, an extra element component such as the conventional bypass temperature adjusting circuit 12 can be eliminated, the system can be made smaller and lighter, and the reliability of the system can be improved.

The present invention is not limited to the above embodiment. For example, although the radial type compressor is used as the non-volume type compressor in the above embodiment, an axial flow type compressor may be used. Further, when the temperature of the refrigerant flowing into the compressor through the bypass circuit rises due to the loss in the compressor and the turbine, the bypass temperature adjusting circuit may be connected. Also in this case, the system efficiency is certainly improved. Further, as the cooling capacity control method, a method such as a compressor rotation speed control using an inverter may be used in combination. Furthermore, this cooling system can also be applied to cooling water for cooling equipment. Other configurations can be further modified without departing from the spirit of the present invention.

[0014]

As described above, in the cooling system according to the present invention, by providing the turbine in the bypass circuit, the driving force of the motor can be reduced by the amount of mechanical energy acquired by the turbine. It is possible to improve efficiency. In addition, the radial compressor can be applied to a small capacity cooling system, and can be made smaller and lighter than a positive displacement compressor. Further, since the bypass temperature adjusting circuit is unnecessary, the system can be made compact and lightweight, and the reliability can be improved. Therefore, this cooling system is extremely useful when applied to an air conditioning system for an aircraft that requires as high efficiency as possible and a small size and weight. It is effective in improving system efficiency.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a conventional example.

[Explanation of symbols]

 1 ... Vapor cycle part 2 ... Bypass circuit 3 ... Evaporator 4 ... Condenser 5 ... Refrigerant circulation circuit 8 ... Expansion valve 10 ... Compressor 13 ... Turbine

Claims (1)

[Claims] 1. An evaporator and a condenser are connected by a refrigerant circulation circuit, an expansion valve is provided between the condenser outlet side and the evaporator inlet side, and the evaporator outlet side and the condenser inlet side are connected. In a cooling system in which a vapor cycle unit is configured by disposing a non-volume type compressor in the cooling system, and further, the compressor outlet side and the compressor inlet side are connected by a bypass circuit, in the bypass circuit coaxial with the compressor. A cooling system comprising a turbine driven by a fluid passing through the cooling system.