JP2000274851A - Air cycle type cooler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently continue operating even if air conditions are changed by connecting an expansion means to a rotary shaft of a motor through a transmission, and controlling a reduction gear ratio of the transmission in response to a torque of the shaft or an input of a motor driving element. SOLUTION: A scroll fluid machine 3 in the air cycle type cooler 1 has a compressor 8 and an expansion unit 9. The compressor 8 is connected directly to one end of a rotary shaft 54 of a motor 11, and the unit 9 is connected to the other end of the shaft 54 through a continuously variable transmission 126. A sensor 125 for detecting a torque of the shaft 54 is attached to the shaft 54, and an output of the sensor is input to a controller 124 together with data of an input value (power) of the motor 11. The transmission 126 is controlled so that, if a compression ratio of the compressor 8 is larger than that of the unit 9, a reduction gear ratio of the transmission 126 is reduced while, in its reverse case, the ratio is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air cycle type cooling apparatus using air as a working medium, and comprising a compression means, an expansion means, and a cooler for cooling compressed air.

[0002]

2. Description of the Related Art Conventionally, an air cycle type cooling apparatus of this type has a compressor (compression means) and an expander (expansion means) as disclosed in Japanese Patent Application Laid-Open No. Hei 5-223376 as an air cycle type air conditioner. And comprises a cooler for cooling the compressed air and an electric element having a rotating shaft, and the like, and the air sucked from the space to be cooled is compressed by the compressor driven by the rotating shaft, and then cooled by the cooler, The low temperature and high pressure air is then expanded by an expander to further lower the temperature,
The cooling effect was exerted by blowing out into the space to be cooled.

In this case, the excluded volume of the compressor is VC, the volumetric efficiency of the compressor is ηC, the excluded volume of the expander is VE, the volumetric efficiency of the expander is ηE, the outlet air density of the compressor is ρ1, and the volume of the expander is Assuming that the inlet air density is ρ2, the following relational expression holds.

ΗC * VC * ρ1 = ηE * VE * ρ2 VC / VE = (ηE * ρ2) / (ηC * ρ1) That is, the respective excluded volume ratios are the outlet air density of the compressor and the inlet air density of the expander. It is designed with the ratio of

[0005]

As is apparent from this relational expression, when each air condition changes, all the right sides of the above relational expression become variables. Therefore, when the pressure (flow rate) of the air flowing into the expander changes and the expansion ratio of the expander and the compression ratio of the compressor differ from the design value, the power recovery rate changes, and the intake air When the conditions change or transition, the expansion machine speeds up or decelerates, making it impossible to recover the expansion work of the air. As a result, the power (input) recovery rate of the electric elements deteriorates and the system efficiency deteriorates. there were.

The present invention has been made to solve the above-mentioned conventional technical problem, and provides an air cycle type cooling device capable of performing efficient operation even when air conditions change. The purpose is to:

[0007]

That is, an air cycle type cooling device according to the present invention uses air as a working medium, compressing means,
An expansion means and a cooler for cooling the compressed air, comprising an electric element having a rotating shaft, the compression means being driven by the rotating shaft, and the expanding means being attached to the rotating shaft via a transmission. The control device controls the reduction ratio of the transmission according to the torque of the rotating shaft or the input of the electric element.

According to a second aspect of the present invention, in addition to the above, in addition to the above, the control unit controls the compression ratio of the compression unit and the expansion of the expansion unit based on the torque of the rotating shaft or the input of the electric element. When the compression ratio is greater than the expansion ratio, the reduction ratio of the transmission is reduced, and when the expansion ratio is greater than the compression ratio, the reduction ratio of the transmission is increased.

Further, in the air cycle type cooling device according to the third aspect of the present invention, in addition to the above inventions, the control device executes the reduction ratio control of the transmission after a predetermined mask time.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a configuration diagram of an air cycle type cooling device 1 to which the present invention is applied. The cooling device 1
For example, it cools the inside of a prefabricated refrigerator / refrigerator or the inside of a low-temperature tank (hereinafter, referred to as a cooled space 2). A water heat exchanger 4 and an air-air heat exchanger 6
And a dehumidifier 7.

The scroll fluid machine 3 includes a compressor (compression means) 8, an expander (expansion means) 9, and a motor (electric element) 11. The compressor 8 is a motor 11
The expander 9 is connected to one end of the rotating shaft 54 and driven, and the expander 9 is connected to the rotating shaft 54 via a continuously variable transmission 126 described later.
Is connected to the other end.

The suction port 1 formed in the space to be cooled 2
2 is connected to an air pipe 13. After passing through the heat exchanger 6, the air pipe 13 passes through the suction port 8 of the compressor 8.
Connected to S.

An air pipe 14 is connected to a discharge port 8D of the compressor 8, and the air pipe 14 passes through the heat exchanger 4 and further passes through the heat exchanger 6, and It is connected to the inlet 9S. An air pipe 16 is connected to a discharge port 9 </ b> D of the expander 9, and is connected via a dehumidifier 7 to an air outlet 17 provided in the space 2 to be cooled.

In the cooling device 1, the air in the space to be cooled 2 is sucked from the suction port 12 by the compressor 8 driven by the motor 11, passes through the air pipe 13, and passes through the heat exchanger 6. Is sucked into the compressor 8 from the suction port 8S and compressed. The compressed high-temperature and high-pressure air enters the air pipe 14 from the discharge port 8D, passes through the heat exchanger 4, and
It passes through the heat exchanger 6 and is sucked into the suction port 9S of the expander 9.

The heat exchanger 4 is provided with a water pipe 18, and the high-temperature and high-pressure air discharged into the air pipe 14 exchanges heat with the cooling water flowing through the water pipe 18 while passing through the heat exchanger 4. And cooled. Further, even in the process of passing through the heat exchanger 6, heat is exchanged with the intake air flowing through the air pipe 13 to be further cooled.

As a result, the air that has exited the heat exchanger 6 enters the expander 9 at a low temperature and a high pressure. The low-temperature and high-pressure air expands in the expander 9 to reduce the pressure, and the air that has flowed out from the discharge port 9D of the expander 9 to the air pipe 16 has a lower temperature due to the pressure drop. And after being dehumidified through the dehumidifier 7,
The air is blown out from the air outlet 17 into the space to be cooled 2. By repeating the compression-cooling-expansion cycle using the direct air as a medium as described above, the inside of the cooled space 2 can be cooled to the freezing temperature.

Here, a sensor 125 for detecting the torque of the rotating shaft 54 is connected to the rotating shaft 54 of the motor 11, and the output of the sensor 125 and the data of the input value (power) of the motor 11 are stored in the control device. 124. The continuously variable transmission 126 is controlled by the control device 124 to adjust the rotation speed of the expander 9.

The control device 124 controls the reduction ratio of the continuously variable transmission 126 according to the torque of the rotating shaft 54 detected by the sensor 125 (or the input value of the motor 11).
That is, the control device 124 controls the torque (or
Based on the input value of the motor 11), the compressor 8
Of the compressor 8 and the expansion ratio of the expander 9 are compared.
Is smaller than the expansion ratio of the expander 9, the reduction ratio of the continuously variable transmission 126 is reduced. If the expansion ratio of the expander 9 is larger than the compression ratio of the compressor 8, Increase the reduction ratio.

The control device 124 includes a continuously variable transmission 126.
When changing the speed reduction ratio, the speed reduction ratio is controlled after a predetermined mask time. That is, the control device 124 determines the torque of the rotating shaft 54 detected by the sensor 125 (or the input value of the motor 11).
After a certain mask time has passed since the detection of the speed change, the reduction ratio of the continuously variable transmission 126 is controlled.

The operation of the above configuration will now be described. When the motor 11 is rotated, its rotational force is transmitted to the compressor 8 via the rotary shaft 54 and also to the expander 9 via the continuously variable transmission 126. In the compressor 8, the suction port 8S
Is compressed, and the compressed air is discharged from the discharge port 8D.

The high-temperature and high-pressure air discharged from the compressor 8 in this manner is cooled by the heat exchangers 4 and 6 as described above, and then becomes low-temperature and high-pressure, and enters the intake port 9S of the expander 9. Reach. The expander 9 expands the air flowing from the suction port 9S. The air whose temperature has decreased due to this expansion is discharged to the discharge port 9D.
Is discharged from.

Pressure fluid (air) in the expander 9
The force generated by the expansion of the motor 11 is transmitted to the rotating shaft 54 via the continuously variable transmission 126 to compensate for the rotation of the motor 11. At this time, the control device 124 controls the torque of the rotating shaft 54 (or the motor 11), the compressor 8
Is compared with the expansion ratio of the expander 9.

That is, when the torque is large, the compression ratio is larger than the expansion ratio, and it can be seen that the expander 9 is about to decelerate. When the torque is small, the expansion ratio is larger than the compression ratio, and it can be seen that the expander 9 is about to increase in speed.

Therefore, when the compression ratio of the compressor 8 is larger than the expansion ratio of the expander 9, that is, when the torque is large, the control device 124 reduces the reduction ratio of the continuously variable transmission 126 (to reduce the gear). When the expansion ratio of the expander 9 is larger than the compression ratio of the compressor 8, that is, when the torque is small,
The control device 124 increases the reduction ratio of the continuously variable transmission 126 (heavier gear). Thereby, the compressor 8 and the expander 9
To match the rotation speed.

Thus, the disadvantage that the expansion machine 9 is accelerated or decelerated during conditions such as a change in the density of the intake air or during a transition and the like, and the power recovery rate in the expansion machine 9 is reduced is prevented beforehand. Will be able to

Further, since the control device 124 controls the reduction ratio of the continuously variable transmission 126 after a predetermined mask time, it is possible to avoid useless control by using the inertia moment and the inertia energy.

[0027]

As described above in detail, according to the present invention, in a pneumatic cycle type cooling apparatus including air as a working medium, a compression means, an expansion means, and a cooler for cooling compressed air, a rotating shaft is provided. The expansion means drives the compression means by this rotation shaft, and the expansion means is connected to the rotation shaft via a transmission, and the control device controls the torque of the rotation shaft or the input of the electric element to control the transmission. Since the reduction ratio is controlled, for example, based on the torque of the rotating shaft or the input of the electric element, the control device compares the compression ratio of the compression means with the expansion ratio of the expansion means. If the ratio is greater than the expansion ratio, reduce the reduction ratio of the transmission,
When the expansion ratio is larger than the compression ratio, it is possible to make the rotation speeds of the compression unit and the expansion unit coincide by increasing the reduction ratio of the transmission.

Thus, it is possible to avoid the disadvantage that the power recovery rate of the expansion means is reduced when the intake air condition is changed or during a transition or the like, and to remarkably improve the operation efficiency of the entire apparatus. It becomes something.

According to the third aspect of the present invention, in addition to the above, the control device executes the reduction ratio control of the transmission after a predetermined mask time, so that the inertia energy of the inertia moment is used. Then, the operation efficiency can be improved without performing unnecessary fine control, and the system design becomes easy.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an air cycle type cooling device to which the present invention is applied.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 air cycle type cooling device 2 space to be cooled 3 scroll fluid machine 4 air-water heat exchanger 6 air-air heat exchanger 8 compressor 9 expander 11 motor 54 rotation axis 124 control device 125 sensor 126 stepless transmission

Claims (3)

[Claims] 1. An air cycle type cooling device comprising air as a working medium, compression means, expansion means, and a cooler for cooling compressed air, comprising: an electric element having a rotating shaft; While driving the compression means, the expansion means is connected to the rotating shaft via a transmission, and the control device controls the reduction ratio of the transmission according to the torque of the rotating shaft or the input of the electric element. An air cycle type cooling device characterized by controlling. 2. The control device compares the compression ratio of the compression means with the expansion ratio of the expansion means based on the torque of the rotating shaft or the input of the electric element. 2. The air cycle type cooling apparatus according to claim 1, wherein the reduction ratio of the transmission is reduced, and when the expansion ratio is larger than the compression ratio, the reduction ratio of the transmission is increased. 3. The air cycle type cooling device according to claim 1, wherein the control device executes reduction ratio control of the transmission after a predetermined mask time.