JP3160069B2 - refrigerator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerator that saves energy by using a refrigerant having a large pressure difference between a condensing pressure and an evaporation pressure as a refrigerant and recovering the pressure difference as power.

[0002]

2. Description of the Related Art In recent years, it has been found that ozone is decomposed by chlorofluorocarbons, which has become a serious problem for the global environment. In other words, when CFCs are released into the atmosphere from refrigerators, etc., they rise in the atmosphere and reach the ozone layer that is formed so as to enclose the earth, where they decompose ozone, a component of the ozone layer. become. Therefore, there is a risk that the ozone layer will disappear if Freon continues to be released, and a large amount of harmful rays such as ultraviolet rays, which are conventionally blocked by the ozone layer, will reach the earth. It was also found that CFCs, together with carbon dioxide, cause global warming. This will have a serious effect on ecosystems and the like, and may also destroy the global environment. For this reason, in the near future, the production of all types of CFC-based refrigerants may be stopped.

[0003] Therefore, a CFC-based refrigerant which has been conventionally used in equipment such as a refrigerator is changed to a non-CFC-based refrigerant which does not affect the global environment.
At present, use of ammonia which is inexpensive and has a good coefficient of performance has been proposed as the non-CFC-based refrigerant.

[0004] Recently, the inventor has proposed an energy-saving refrigerator using an ammonia refrigerant. This utilizes the fact that ammonia is significantly overheated when compressed by a compressor. That is, the gas refrigerant discharged from the compressor is once subjected to heat exchange with a hot water heat exchanger or the like to lower the temperature and is then introduced into the condenser. This makes the condenser smaller and
Hot water can be obtained by the hot water heat exchanger. Therefore, it can be supplied to a building or the like via hot water supply means such as a hot water supply pipe or the like, so that hot water supply equipment can be eliminated or reduced, and a remarkable energy-saving refrigerator can be obtained.

[0005]

However, when ammonia is used as a refrigerant, there are the following problems. In other words, since ammonia has a much lower specific gravity than Freon-based refrigerants, especially in a turbo refrigerator that compresses using the centrifugal force of refrigerant gas molecules, high efficiency is required to obtain sufficient pressure during compression. It is necessary to use a multi-stage compressor. Further, the pressure difference between the condensing pressure and the evaporating pressure in the centrifugal chiller is about 11.5 kg in the case of ammonia.
/ Cm 2, which is considerably larger than about 1.4 kg / cm 2 of Freon 11 which is a common Freon-based refrigerant used in refrigerators. Therefore, in order to smoothly drive the compressor, the power of the electric motor is set to be slightly larger than that of the conventional CFC-based refrigerant. This results in, for example, an increase in the size of the electric motor as compared with the related art, which is against energy saving.

The present invention has been proposed to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a refrigerating machine which can efficiently drive a compressor to save energy and save energy. It is to be.

[0007]

According to a first aspect of the present invention, there is provided a refrigerator in which a compressor, a condenser, and an evaporator are driven by an electric motor. An expansion turbine is provided between the evaporator and the evaporator. The expansion turbine is provided so as to obtain power by a pressure difference of the refrigerant, and the power from the expansion turbine is used as a part of the driving force of the electric motor. It is provided so as to be recovered, and ammonia is used as the refrigerant.

[0008]

The operation of the refrigerator of the present invention having the above-described structure is as follows.

That is, an expansion turbine is provided between the condenser and the evaporator, and the expansion turbine is provided so that power can be obtained by the pressure difference of the refrigerant.
In the expansion turbine, power is obtained from the pressure difference between the condensing pressure and the evaporation pressure, and the power is recovered as part of the driving force of the electric motor that drives the compressor, so that the driving power can be reduced. Thus, it is possible to provide a high-efficiency and energy-saving refrigerator.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the refrigerator of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the refrigerator of this embodiment includes a compressor 2 driven by an electric motor 1, a condenser 3 and an evaporator 4, and is connected by a refrigerant pipe 5.
An expansion turbine 6 is provided in a refrigeration circuit in which ammonia is used as a refrigerant. The expansion turbine 6 is disposed between the condenser 3 and the evaporator 4 and is a part of a refrigeration circuit. The rotation shaft 6a of the expansion turbine 6 is connected by a connecting means 7 such as a shaft joint or a gear coupling. It is directly connected to the rotating shaft 1a of the electric motor 1. Although not shown, the inside of such an expansion turbine 6 is provided with an impeller-like runner around a rotating shaft, and when a refrigerant is supplied, a radial inflow type flows in from the outer periphery of the runner and flows out from the center of the runner. Is configured.

The operation of the embodiment constructed as described above is as follows.
It looks like this: The compressor 2 is driven by the rotation of the electric motor 1, and the ammonia refrigerant is compressed by the compressor 2,
The refrigerant is discharged to the refrigerant pipe 5 as a high-pressure gas refrigerant. This gas refrigerant is supplied to the condenser 3 and exchanges heat with the cooling water, and is condensed and completely liquefied. This high-pressure liquid refrigerant is supplied to the expansion turbine 6 via the refrigerant pipe 5. In the expansion turbine 6, when the runner (not shown) flows in, it is rapidly expanded to a low pressure and low temperature, and the runner is rotated by the pressure difference from the runner outflow. Expansion turbine 6
Is discharged to the evaporator 4. In the evaporator 4, heat exchange is performed with cold water or brine of an air conditioner or the like, and evaporates at a low temperature to become a gas refrigerant, which is sucked into the compressor 2. In this way, it works as a refrigeration circuit. By the way, in the expansion turbine 6, the rotation shaft 6a is rotated by the rotation of the runner due to the pressure difference at the time of expansion of the refrigerant, and the rotation shaft 1a of the motor 1 directly connected to the rotation shaft is rotated to drive the motor 1. Will be done. At this time, the rotation speed of the runner (not shown) is about 3000 to 3600 rpm.
, And the rotation speed of the rotating shaft 1a of the electric motor 1 becomes the same as the rotation speed of the rotating shaft 1a. The flow rate of the refrigerant during use of the above-described refrigeration circuit is always constant.

As described above, in the refrigerator of this embodiment, since the expansion turbine 6 is provided, the pressure difference between the condensing pressure and the evaporation pressure of the refrigerant can be recovered as power. The driving power can be reduced, and the energy can be significantly reduced. In particular, since the refrigerant is ammonia, the pressure difference in the centrifugal chiller is about 11.
Since it is as large as 5 kg / cm @ 2, the runner of the expansion turbine 6 can be sufficiently rotated to recover a large amount of refrigerant compression power. At this time, the coefficient of performance, which is the refrigeration capacity with respect to the input of the electric motor 1, is improved to about 5 to 6 as compared with about 3 to 4 of the conventional centrifugal chiller. Therefore, the power for compression is required to be slightly larger than that of the CFC refrigerant having a pressure difference of about 1.4 kg / cm2, but by recovering the power, it can be sufficiently compressed by a small motor like the CFC refrigerant. Can be performed.

The refrigerator of the present invention is not limited to the above-described embodiment, and the specific shape of each member, or the mounting position and method of each member can be appropriately changed. For example, the refrigeration circuit can be appropriately changed, such as a circuit using a liquid receiver. In addition, the above-described embodiment is not limited to the turbo type compressor, but can be applied to a screw type, a rotary type, a scroll type, etc. as appropriate, and can obtain a refrigerator that saves energy. Further, the refrigerant used in the refrigerator is not limited to ammonia, and a non-CFC-based refrigerant capable of recovering power, which has a large pressure difference between the condensing pressure and the evaporating pressure, can be used as appropriate.

The rotation speed of the expansion turbine 6 is about 500.
In the case where the speed is higher than that of the electric motor 1 such as 0 rpm, a speed reducing means 8 such as an automatic clutch which can be automatically engaged and disengaged is provided between the electric motor 1 and the expansion turbine 6 as shown in FIG. It is possible to drive the electric motor 1 with the recovered power at a reduced speed.

[0016]

The refrigerator of the present invention can recover power by utilizing the pressure difference between the condensing pressure and the evaporating pressure, thereby reducing the driving power of the motor driving the compressor. And a refrigerator that is highly efficient and energy saving can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an embodiment of a refrigerator of the present invention.

FIG. 2 is a schematic view showing another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Electric motor 2 ... Compressor 3 ... Condenser 4 ... Evaporator 5 ... Refrigerant piping 6 ... Expansion turbine 7 ... Connection means 8 ... Reduction means

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-57-108555 (JP, A) JP-A-63-15045 (JP, A) JP-A-4-128570 (JP, A) JP-A-5-108 98902 (JP, A) Japanese Utility Model Showa 58-144261 (JP, U) Japanese Utility Model Showa 61-98954 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F25B 11/02 F25B 11 / 00 F25B 9/06

Claims (1)

(57) [Claims] 1. A refrigerator in which a compressor, a condenser, and an evaporator are driven by an electric motor, wherein an expansion turbine is disposed between the condenser and the evaporator, and the expansion turbine has a pressure difference of refrigerant. And power is provided by the expansion turbine so as to be recovered as part of the driving force of the electric motor, and ammonia is used as the refrigerant. Machine.