JP2887976B2 - Cooling system - Google Patents

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 a vehicle, an air conditioner in 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 includes a vapor cycle unit 1 and a bypass circuit 2. The vapor cycle unit 1 connects the evaporator 3 and the condenser 4 with a refrigerant circulation circuit 5 filled with a refrigerant p such as freon gas. In the condenser 4, the refrigerant p is discharged toward the outside air r. To this end, 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 adiabatically expanding the transferred refrigerant p. An expansion valve 8 is provided, a temperature sensing part 9 for detecting the temperature of the refrigerant p in the refrigerant circulation circuit 5 on the outlet side of the evaporator 3 and the condenser 4 and an adiabatic compression of the transferred refrigerant p. A radial type compressor 10 is provided. Also disposed a motor M ₁ for driving 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 has a bypass valve 11a controlled by a detection signal a from the temperature sensing part 9. doing.

Next, the operation of the 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 water and foreign substances from the liquefied refrigerant p are removed by the filter 6,
It flows into the receiver 7. In this receiver 7, the liquefied refrigerant p is stored. 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, the liquid phase of the refrigerant p is vaporized by performing heat exchange with the air q. At this time, the air q is cooled and sent to a cooling room or the like. The temperature sensing section 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 has taken heat from the air q and has flowed to the outlet side of the evaporator 3. By adjusting the opening of the expansion valve 8 according to the detection signal a, the refrigerant p is made to flow into the compressor 10 in a substantially complete vaporized state. If the set temperature is constant, the expansion valve 8 is adjusted to the opening increasing side as the amount of the air q increases (that is, as the load increases), and the expansion valve 8 is adjusted to the opening decreasing side as the amount of the air q decreases. Become. Thus, when the refrigerant p compressed by the compressor 10 flows into the condenser 4, the refrigerant p releases its heat by heat exchange with the outside air r, and is cooled and liquefied again. By repeating such a cycle of the refrigerant p, the cooling system can operate to pump out heat by the evaporator 3 and release it by the condenser 4.

[0004] Incidentally, the compressor 10 has a problem that, when the inflowing refrigerant p is less than a required amount, surging occurs and causes a failure as a characteristic of the non-volume type. Therefore, when the expansion valve 8 is being throttled, the compressor 10 is opened by opening the bypass valve 11 a provided in the bypass circuit 2.
A part of the refrigerant p flowing out of the evaporator 3 is replenished to the refrigerant p flowing out of the evaporator 3 so as to ensure the minimum flow rate and flow into the compressor 10.

[0005]

However, when the refrigerant p is fed back 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 must be compressed at zero. Therefore, the motor M
A part of the compression work performed by the compressor 10 through the drive ₁ is wasted, resulting in a problem that the efficiency of the system is reduced. Further, although the inlet temperature of the compressor 10 (that is, the temperature of the temperature sensing portion 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. The inflow causes an increase in the inlet temperature. For this reason, a bypass temperature control circuit 12 having a bypass valve 11b is conventionally provided 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 control circuit 12 to the compressor 10 inlet. It is mixed with the refrigerant p on the side to cancel the temperature change. For this reason, the number of parts increases, and there is a drawback that costs and weight increase. Further, the radial compressor has features of being smaller and lighter than a positive displacement compressor, but a small capacity system has a small flow rate, so that the radial compressor cannot be applied.

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

[0007]

In order to achieve the above object, the present invention employs the following configuration.

That is, the cooling system according to the present invention comprises:
The evaporator and the condenser are connected by a refrigerant circulation circuit, and an expansion valve is provided 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, the fluid passing through the bypass circuit is coaxial with the compressor. A driven turbine is provided.

[0009]

With this configuration, when a turbine is provided, when the refrigerant compressed by the compressor passes through the turbine, it performs expansion work on the turbine,
The energy of the refrigerant is converted into mechanical energy and transmitted to a compressor disposed coaxially with the turbine. Therefore, the driving force of the motor can be reduced by the mechanical energy obtained by the turbine, and the system efficiency is improved. In addition, the temperature of the refrigerant is reduced from the temperature at the compressor outlet side by performing expansion work on the turbine. It can be unnecessary.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG. In addition, the same reference numerals are given to portions common to FIG.

This cooling system has the basic configuration shown in FIG. 2 and includes a turbine 13 driven by a fluid passing through a bypass valve 11a in the bypass circuit 2. The turbine 13, which has bound to the compressor 10 on a single axis, are disposed motor M ₂ to drive the compressor 10.

When such a configuration is adopted, when a part of the refrigerant p compressed by the compressor 10 passes through the turbine 13, it performs expansion work on the turbine 13,
The energy of the refrigerant p is converted into mechanical energy,
The power is transmitted to the turbine 13 and the compressor 10 disposed on a single shaft. In other words, a part of the compression work performed by the compressor 10 is recovered by the turbine 13. Therefore, driving force of the motor M _2, the turbine 1
3 will be is be small than an amount corresponding driving force of the motor M ₁ of the mechanical energy to win, it is possible to reliably improve the system efficiency as compared with the prior art. Also, the refrigerant p
Is lower than the temperature at the exit of the compressor 10 due to the expansion work on the turbine 13, so that there is no large rise in temperature at the entrance of the compressor 10. For this reason, an extra component such as the conventional bypass temperature adjustment circuit 12 can be eliminated, and the system can be reduced in size and weight, and the reliability of the system can be improved.

Note that the present invention is not limited to the above embodiment. For example, in the above-described embodiment, a radial type compressor is used as a non-displacement type compressor, but an axial flow type compressor may be used. Further, when the temperature of the refrigerant flowing into the compressor through the bypass circuit increases due to loss in the compressor and the turbine, a bypass temperature adjustment circuit may be connected. Also in this case, the system efficiency is definitely improved. Further, as a method of controlling the cooling capacity, a method of controlling the number of revolutions of a compressor using an inverter may be used together. Furthermore, this cooling system can 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 mechanical energy obtained by the turbine. It is possible to improve the efficiency. Further, the radial compressor can be applied to a small-capacity cooling system, and can be made smaller and lighter than a positive displacement compressor. Furthermore, since a bypass temperature adjusting circuit is not required, the size and weight of the system can be reduced, 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 and miniaturization as possible. This is effective in improving system efficiency.

[Brief description of the drawings]

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

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

[Explanation of symbols]

 DESCRIPTION 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)

(57) [Claims] An evaporator and a condenser are connected by a refrigerant circulation circuit, and an expansion valve is provided between the condenser outlet and the evaporator inlet, and an expansion valve is provided between the evaporator outlet and the condenser inlet. In a cooling system in which a non-displacement type compressor is arranged to form a vapor cycle section, and the compressor outlet side and the compressor inlet side are connected by a bypass circuit, A cooling system comprising a turbine driven by a fluid passing through the cooling system.