KR20130142201A - Cooling device for high temperature superconducting apparatus and operation method therefor - Google Patents

Abstract

The cooling apparatus 1 of the high temperature superconducting apparatus of the present invention includes a turbo compressor 2, a main heat exchanger 3, an expansion turbine 4, a sub-heat exchanger 5 for heat-exchanging refrigerant gas and a cooling liquid, and circulation. A pump 7, a temperature measuring means 10 for measuring the temperature of the coolant, a first waste flow path L1, and a second waste flow path L2 for circulating the coolant include a sub-heat exchanger ( 5) has a path through which the refrigerant gas flows in parallel, and has a first heat exchange part 5a for exchanging the refrigerant gas with each other, and a second heat exchange part 5b for exchanging heat so that the refrigerant gas and the coolant face each other.

Description

COOLING DEVICE FOR HIGH TEMPERATURE SUPERCONDUCTING APPARATUS AND OPERATION METHOD THEREFOR}

The present invention relates to a cooling device for a high temperature superconducting device and a method of operating the same.

This application claims priority based on Japanese Patent Application No. 2012-092079 for which it applied to Japan on April 13, 2012, and uses the content here.

HTS devices such as transformers, power transmission cables, and motors using high temperature superconducting (hereinafter referred to as "HTS") need to be cooled to about 60 to 80K in order to maintain a superconducting state. In order to maintain a superconducting state, a cooling system (freezer) is indispensable, and in recent years, a refrigerator having a freezing capacity of about 2 to 10 kPa is required. The HTS apparatus is cooled by, for example, liquid nitrogen, which is circulated by the liquid nitrogen circulation device in a subcool state. The liquid nitrogen in the liquid nitrogen circulation device is cooled by the freezer.

The subcool state refers to a state in which the liquid temperature is lower than the saturation temperature. For example, in the case of liquid nitrogen under atmospheric pressure, it refers to a liquid nitrogen state having a temperature from the boiling point (about 77K) to the freezing point (about 63K). In addition, a saturation temperature means the temperature at which the pressure of a certain liquid is equal to the saturation vapor pressure.

As the freezer required for the HTS apparatus, not only its size but also its cooling performance such as cooling temperature, freezing capacity, and freezing efficiency is important. The freezing capacity (60-80 K, 0.1-0.6 kPa) of GM refrigerator or Sterling refrigerator is not applicable. In addition, the development of a GM refrigerator and a sterling refrigerator having a refrigeration capacity of several degrees is difficult due to a heat exchanger installed inside the refrigerator.

Refrigerators required for HTS appliances include Brayton Cycle Refrigerators, in addition to GM and Sterling refrigerators.

For example, as described in Patent Document 1, a Brayton cycle refrigerator using a neon gas as a refrigerant gas (a working fluid and a working fluid) and using liquid nitrogen as a cooling liquid has been developed. The neon gas circulating in the Brayton cycle freezer and the liquid nitrogen circulating in the liquid nitrogen circulating device exchange heat in the sub-heat exchanger, thereby cooling the liquid nitrogen to the subcool state.

In addition, it is considered preferable to use a plate fin heat exchanger as the sub-heat exchanger in order to efficiently subcool the liquid nitrogen by the liquid nitrogen circulation device. The plate fin heat exchanger can be miniaturized.

Japanese Unexamined Patent Publication No. 2011-106755

However, when the neon gas as the refrigerant of the Brayton cycle refrigerator is lower than the freezing point 63K of the liquid nitrogen as the cooling liquid, the liquid nitrogen coagulates in the subheat exchanger, thereby blocking the liquid nitrogen flow path in the subheat exchanger.

In the liquid nitrogen circulation device, a heating means (for example, a heater or the like) may be provided so that the liquid nitrogen flow path does not freeze before cooling the HTS device, which is the object to be cooled, and the liquid nitrogen temperature may be controlled to a temperature higher than the freezing point. have. However, a problem arises in that unnecessary equipment such as a heater is required. The original need for unnecessary equipment, such as heaters, is to overcool the liquid nitrogen, i.e. the Brayton cycle freezer does not operate efficiently.

In addition, if the state where the liquid nitrogen is solidified in this way, the operation change of the Brayton cycle freezer cannot be appropriately performed in response to the case where the operation state of the HTS device is changed rapidly, and as a result, the HTS device is cooled to a constant temperature. There was a problem in that the liquid nitrogen temperature to be maintained at an appropriate temperature could not be maintained.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and it is possible to make the subcool state without solidifying the cooling liquid and to maintain the cooling liquid at an appropriate temperature even when the operating state of the cooled object changes drastically. It is an object of the present invention to provide a cooling device and a driving method thereof.

To solve these challenges,

The first aspect of the present invention is a turbo compressor for compressing and circulating a refrigerant gas,

A main heat exchanger for cooling the compressed refrigerant gas by heat exchange with the returned refrigerant gas (refrigerant gas before compression);

An expansion turbine for thermally expanding and expanding the cooled refrigerant gas;

A sub-heat exchanger for heat-exchanging the cryogenic refrigerant gas and the cooling liquid exiting the expansion turbine,

A circulation pump for circulating the coolant between the sub-heat exchanger and the object to be cooled,

Temperature measuring means for measuring a temperature of the cooling liquid;

A first waste flow passage constituting a circulation path for circulating the refrigerant gas after the heat exchange in the sub-heat exchanger to the turbo compressor via the main heat exchanger;

A second waste flow passage constituting a circulation path for circulating the cooling liquid after the heat exchange in the sub-heat exchanger to the circulation pump,

The subheat exchanger

A first heat exchange part having a path in which the refrigerant gas flows in parallel, and wherein the refrigerant gas exchanges heat with each other;

Provided is a cooling apparatus for a high temperature superconducting device having a second heat exchanger configured to exchange heat between the refrigerant gas heat exchanged in the first heat exchanger and the cooling liquid.

Moreover, in the 1st aspect of this invention, it is preferable that the said temperature measuring means measures the temperature of the said cooling liquid after heat-exchanging in the said sub heat exchanger.

In addition, in the first aspect of the present invention, the refrigerant gas is a mixed gas of neon gas, helium gas and neon gas, a mixed gas of hydrogen and neon gas, a mixed gas of hydrogen and helium gas, or neon gas, helium gas or It is preferable that it is any of the mixed gas which mixed the inert gas with the said mixed gas.

Moreover, in 1st aspect of this invention, it is preferable that the said cooling liquid is liquid nitrogen.

Moreover, the 2nd aspect of this invention is an operation method of the cooling apparatus of the high temperature superconducting apparatus of the 1st aspect of this invention,

A method of operating a cooling apparatus of a high temperature superconducting device which controls the temperature of a refrigerant gas by the rotational speed of a turbo compressor so that the cooling liquid in a 2nd waste flow path becomes a subcool state.

Moreover, in the 2nd aspect of this invention, when the temperature of the cooling liquid in a said 2nd waste flow path becomes low, it is preferable to reduce the rotation speed of the said turbo compressor.

Moreover, in the 2nd aspect of this invention, when the temperature of the cooling liquid in a said 2nd waste flow path becomes high, it is preferable to raise the rotation speed of the said turbo compressor.

Moreover, in the 2nd aspect of this invention, the circulation flow volume of the said cooling liquid is controlled by the rotation speed of the said circulation pump so that the cooling liquid in a 2nd waste flow path may become a subcool state, and the rotation of the said circulation pump is carried out. It is preferable to control the number by inverter control.

According to the cooling apparatus of the high temperature superconducting apparatus of the present invention, a subheat exchanger for subcooling the coolant in the second waste flow passage is provided in the cooling apparatus, and the first heat exchange part in the subheat exchanger is used in the first waste flow passage. Since the refrigerant gas is heat-exchanged by itself and the cooling liquid in the second waste flow path is cooled by the second heat exchanger, the cooling liquid is not solidified in the sub-heat exchanger.

Moreover, according to the operating method of the cooling device of the high temperature superconducting apparatus of this invention, since the rotation speed of the turbocompressor installed in the 1st waste flow path is controlled only according to the temperature change of the cooling liquid of the exit side of a subheat exchanger, the to-be-cooled body Even when there is a sudden change in the operating state, the cooled object can be cooled appropriately and efficiently without solidifying the cooling liquid in the sub-heat exchanger.

BRIEF DESCRIPTION OF THE DRAWINGS It is a system diagram which shows the cooling device of the high temperature superconducting apparatus which is one Embodiment of this invention.
FIG. 2 is an enlarged schematic diagram showing a sub-heat exchanger used for a cooling device of a high temperature superconducting device according to one embodiment of the present invention. FIG.
3 is a graph showing the relationship between the freezing capacity of the Brayton cycle refrigerator to which the present invention is applied and the liquid nitrogen temperature at the outlet of the sub-heat exchanger.

EMBODIMENT OF THE INVENTION Hereinafter, the refrigerator which is one Embodiment which applied the cooling apparatus of the high temperature superconducting apparatus of this invention is demonstrated in detail using drawing with the operation method. In addition, the drawing used for the following description may expand and show the part which becomes a feature for convenience, and it cannot be concluded that the dimension ratio etc. of each component are the same as the said apparatus actually. In addition, in this invention, the "freezer" and the "cooling device" mean the same content, and the same code | symbol 1 is attached | subjected.

First, the structure of the refrigerator of this embodiment is demonstrated.

As shown in FIG. 1, the combination of the refrigerator 1 and the to-be-cooled body 6 of this embodiment is the turbo compressor 2, the main heat exchanger 3, the expansion turbine 4, and the sub heat exchanger 5. The second circulation path (first waste passage) (L1) provided, the second heat exchanger (5), the to-be-cooled body (6), the circulation pump (7), and the temperature measuring means (10) are installed. 2, a waste flow path (L2) is roughly configured, and the refrigerant gas circulating in the first circulation path (L1) and the coolant circulating in the second circulation path (L2) are allowed to exchange heat in the sub-heat exchanger (5). It is.

More specifically, the refrigerator 1 includes a turbo compressor 2, a main heat exchanger 3, an expansion turbine 4, a subheat exchanger 5, a temperature measuring means 10, and a circulation pump 7. It is comprised and only the to-be-cooled body 6 is provided in the exterior of the refrigerator 1. As shown in FIG. In addition, all the components of the refrigerator 1 other than the to-be-cooled body 6 are accommodated in the same vacuum container (cold box).

In addition, as shown in FIG. 1, the refrigerator 1 of this embodiment heat-compresses and compresses refrigerant gas, such as neon gas, by the turbo compressor 2, and the refrigerant gas of the high pressure side and the low pressure side of the main heat exchanger 3 are carried out. When the returned refrigerant gas exchanges heat, the refrigerant gas on the high pressure side is cooled, and the cooled refrigerant gas is thermally expanded in the expansion turbine 4 so that the refrigerant gas itself becomes cryogenic and the cryogenic refrigerant gas in the sub-heat exchanger 5. And a cooling liquid such as liquid nitrogen sent out from the circulation pump 7 cool the cooling liquid by heat exchange, and for example, the cooled object 6 such as an HTS apparatus is cooled by the cooling liquid.

As the refrigerant gas, helium, neon or hydrogen having a boiling point lower than nitrogen and a mixed gas thereof, or a mixed gas obtained by mixing some gases with an inert gas such as nitrogen or argon can be used.

In addition, as a cooling liquid, although it does not specifically limit, For example, liquid nitrogen can be used.

The first circulation path L1 includes a turbo compressor 2 for compressing and circulating refrigerant gas, a main heat exchanger 3 for cooling the adiabatic compressed refrigerant gas by heat exchange with the returned refrigerant gas, and the cooled refrigerant gas. Is a circulation path circulated to the turbocompressor 2 via an expansion turbine 4 for adiabatic expansion, and a sub-heat exchanger for heat-exchanging the cryogenic refrigerant gas and the cooling liquid derived from the expansion turbine 4.

The turbo compressor 2 is provided in the 1st circulation path L1 in order to adiabatic-compress and circulate a refrigerant gas. In this embodiment, although the one-stage turbo compressor is illustrated, it is not limited to this. In addition, it is good also as a two stage turbo compressor provided with an intercooler.

In addition, the turbo compressor 2 may use what is driven by an inverter. When the turbo compressor is driven by the inverter, when the outlet side pressure of the turbo compressor 2 is higher than a predetermined value, the output frequency of the inverter can be changed to reduce the rotation speed of the turbo compressor 2. Therefore, it is possible to maintain the outlet side pressure of the turbocompressor 2 below a predetermined value. In this way, if the turbo compressor 2 can control the inverter, the rotation speed can be preferably controlled. Moreover, when the output frequency of an inverter is changed and the rotation speed of the turbo compressor 2 is made large, the outlet pressure of the turbo compressor 2 can be made high.

In addition, a heat exchanger may be provided at the rear end of the outlet of the turbo compressor 2. In this heat exchanger, the hot refrigerant gas from the turbo compressor 2 can be cooled to near the ambient temperature. For example, a water-cooled after cooler is mentioned.

As shown in FIG. 1, the main heat exchanger 3 is provided between the turbo compressor 2 and the expansion turbine 4 in the first circulation path L1, and is thermally compressed by the turbo compressor 2. The refrigerant gas from the turbo compressor 2 is cooled by heat-exchanging the refrigerant gas and the refrigerant gas returned from the sub-heat exchanger 5.

As shown in FIG. 1, the expansion turbine 4 is provided at the rear end of the main heat exchanger 3 in the first circulation path L1, and thermally expands and cools the refrigerant gas cooled by the main heat exchanger 3. Is refrigerant gas. In addition, the expansion turbine 4 may be provided on the same shaft as the turbo compressor 2 so as to have an integral structure. By having an integrated structure, since the power for operating the expansion turbine 4 and the turbo compressor 2 can be united, the refrigerator can be miniaturized.

In addition, although the outlet temperature (corresponding to the temperature of point 1 in FIG. 2) of the expansion turbine 4 depends on the type of refrigerant gas, in the cooling apparatus of the present invention in which the main heat exchanger and the sub-heat exchanger are combined, 55 K to Many are in the 65K range.

As shown in FIG. 1, the sub-heat exchanger 5 is provided at the outlet side of the expansion turbine 4 in the first circulation path L1, and is cooled by the expansion turbine 4 with the cryogenic gas and the cooled object. The cooling liquid for cooling the sieve 6 cools the cooling liquid by heat exchange. That is, the refrigerant to be cooled is cooled by the refrigerant gas cooling the cooling liquid.

As shown in FIG. 1, the circulation pump 7 circulates the cooling liquid in the second circulation path L2.

1, the temperature measuring means 10 for measuring the temperature of the coolant which flows out from the sub-heat exchanger 5 is provided in the 2nd circulation path L2. As the temperature measuring means 10, a thermocouple etc. are mentioned, for example.

Moreover, as the to-be-cooled body 6, HTS apparatuses, such as a superconducting power transmission cable, a superconducting transformer, and a superconducting motor, are mentioned, for example.

Next, the operation method of the refrigerator 1 of this embodiment is demonstrated.

First, in the first circulation path L1, the refrigerant gas is adiabaticly compressed by the turbo compressor 2. Next, the refrigerant gas is introduced into the main heat exchanger 3 to exchange heat with the refrigerant gas (refrigerant gas before thermal insulation compression) returned from the sub-heat exchanger 5. At this time, the adiabatic compressed refrigerant gas is cooled to 65 to 70K.

In addition, since the refrigerant gas heat-insulated and compressed by the turbocompressor 2 becomes high temperature, a heat exchanger may be provided at the rear end of the turbocompressor 2 and the refrigerant gas may be cooled to near the ambient temperature.

Next, in the expansion turbine 4, the pressure (low pressure side pressure, 0.5 to 1 MPa) derived from the expansion turbine 4 at a pressure (high pressure side pressure, 1 to 2 MPa) for introducing refrigerant gas into the expansion turbine 4. ) Is adiabatically expanded to lower the temperature of the refrigerant gas to 55 to 65K.

Next, the refrigerant gas cooled to 55 to 65K by the expansion turbine 4 is introduced into the sub-heat exchanger 5 and heat-exchanges with the cooling liquid for cooling the object to be cooled 6. At this time, the cooling liquid is cooled to a subcool state. For example, when cooling liquid nitrogen to 65K, refrigerant gas temperature rises to about 65-70K.

On the other hand, the coolant in the subcool state circulates through the second circulation path L2 so as to maintain the cooled object 6 at a constant temperature by the circulation pump 7. The temperature range of the subcooled cooling liquid is, for example, the temperature from the boiling point (about 77K) to the freezing point (about 63K) in the case of liquid nitrogen at atmospheric pressure. Moreover, the temperature of the cooling liquid which cools the to-be-cooled body 6 is always monitored by the temperature measuring means 10. FIG. Although the temperature to hold the to-be-cooled body 6 differs somewhat according to HTS apparatuses, in most cases, it maintains cooling about about 70K.

Next, the refrigerant gas (returned refrigerant gas) derived from the sub-heat exchanger (5) is returned to the main heat exchanger (3), and is heat-exchanged with the refrigerant gas thermally compressed by the turbo compressor (2). At this time, the temperature of the refrigerant gas (returned refrigerant gas) derived from the sub-heat exchanger 5 further rises to near the atmospheric temperature. Thereafter, the refrigerant gas (returned refrigerant gas) derived from the subheat exchanger 5 is returned to the inlet side of the turbo compressor.

Thus, in the 1st circulation path L1 provided in the refrigerator 1 of this embodiment, it is the structure which refrigerant gas circulates, and comprises the Brayton cycle.

When the pressure loss of the cooling gas is large in the sub-heat exchanger 5, the expansion turbine 4 is connected to the rear end of the sub-heat exchanger 5 in the first circulation path L1, that is, the main heat exchanger 3 It may be provided at the front end, and a refrigerant gas having a high pressure of 1 to 2 MPa may be introduced into the subheat exchanger 5. Thereby, even if the pressure loss of cooling gas is large in the subheat exchanger 5, it can respond.

Next, the subheat exchanger 5 of this embodiment is demonstrated in more detail based on FIG.

As shown in FIG. 2, in the sub-heat exchanger 5, the first circulation path L1 through which the refrigerant gas flows is parallel to the path L1a and the path L1b (the refrigerant gas in the path L1a and the path ( The first heat exchange part 5a is formed so that the refrigerant gas in L1b) may be parallel flow. Further, in the sub-heat exchanger 5, the second heat exchange part such that the path L2a through which the coolant flows is opposed to the path L1b through which the refrigerant gas flows (the path L1b and the path L2a are opposed to each other). (5b) is formed.

By providing such a flow path in the sub-heat exchanger 5, in the parallel flow part of the 1st heat exchange part 5a, refrigerant gas exchanges with each other, and the temperature of the refrigerant gas cooled by the expansion turbine 4 is more than the freezing point of a cooling liquid. In addition, in the counter flow part of the 2nd heat exchange part 5b, the cooling liquid (subcool state) which cools this refrigerant gas and the to-be-cooled body 6 is heat-exchanged, and cools a cooling liquid.

That is, in the sub-heat exchanger 5, the refrigerant gas and the cooling liquid are heat-exchanged in a state where the cooling liquid is in a sub-cooling state and above the freezing point.

By the way, as shown in FIG. 1, the temperature of a cooling liquid changes with the load fluctuation | variation and operation change of the to-be-cooled body (HTS apparatus) 6. As shown in FIG. On the other hand, according to the refrigerator 1 of this embodiment, since the temperature measuring means 10 is provided in the rear end (namely, the front end of the to-be-cooled body 6) of the sub-heat exchanger 5, the to-be-cooled body ( The temperature of the cooling liquid for cooling 6) can be measured at all times. Moreover, the rotation speed of the turbo compressor 2 can be controlled according to the measured temperature of a cooling liquid. When the measured temperature of the coolant drops, that is, when the load of the to-be-cooled body 6 such as an HTS device is reduced, the rotation speed of the turbo compressor 2 is lowered. On the other hand, when the measurement temperature of the cooling liquid rises, that is, when the load of the to-be-cooled body 6, such as an HTS apparatus, increases, the rotation speed of the turbocompressor 2 will be made high.

As mentioned above, the refrigerating capacity of the refrigerator 1 can be changed by control of the rotation speed of the turbo compressor 2.

In addition, the expansion ratio of the expansion turbine 4 is determined by the relationship between the high pressure side pressure and the low pressure side pressure of the refrigerator 1. It is the compression ratio of the turbo compressor 2 that determines these pressures of the refrigerator 1. The expansion turbine 4 only has a function of expanding the refrigerant gas outlet pressure (high pressure side pressure) increased via the turbo compressor 2 to the refrigerant gas inlet pressure (low pressure side pressure) of the turbo compressor 2, The expansion turbine 4 itself cannot determine the expansion ratio. That is, the expansion ratio of the refrigerant gas of the expansion turbine 4 is determined in accordance with the compression ratio of the refrigerant gas in the turbo compressor 2.

In other words, when the rotation speed of the turbo compressor 2 is lowered, the compression ratio becomes smaller due to the characteristics of the turbo compressor 2, and as a result, the expansion ratio of the expansion turbine 4 becomes smaller, and therefore, the refrigerant derived from the expansion turbine 4. The gas temperature rises more than before the rotation speed is lowered.

On the contrary, when the rotation speed of the turbo compressor 2 is increased, the compression ratio becomes large due to the characteristics of the turbo compressor 2, and as a result, the expansion ratio of the expansion turbine 4 becomes large, so that the refrigerant gas derived from the expansion turbine 4 is increased. The temperature is lower than before the rotation speed is increased.

As mentioned above, according to the refrigerator 1 of this embodiment, by controlling the rotation speed of the turbocompressor 2 quickly according to the load fluctuation | variation and the operation change of the to-be-cooled body 6, such as an HTS apparatus, The temperature can be maintained at an appropriate temperature. Therefore, the to-be-cooled body 6 can be kept at a fixed temperature.

As described above, the refrigerator 1 of the present embodiment includes a sub-heat exchanger for subcooling the cooling liquid (liquid nitrogen) in the second circulation path L2 in the refrigerator 1 constituting the Brayton cycle ( 5), the first heat exchanger 5a in the sub-heat exchanger 5 heats the refrigerant gas (neon gas) in the first circulation path L1 by itself and at the second heat exchanger 5b. It is comprised so that the cooling liquid in 2nd circulation path L2 may be cooled. Therefore, the cooling liquid is not solidified in the subheat exchanger 5.

In addition, according to the operation method of the refrigerator 1 of this embodiment, the rotation of the turbocompressor 2 provided in the 1st circulation path L1 only according to the temperature change of the cooling liquid of the exit side of the sub-heat exchanger 5. Since the number is controlled, even when there is a sudden change in the operating state of the object to be cooled (HTS device) 6, the high temperature superconductor in the HTS device is appropriately and efficiently cooled without solidifying the cooling liquid in the sub-heat exchanger 5. can do.

(Control of the rotation speed of the circulation pump 7)

In the cooling apparatus of the high temperature superconducting apparatus of the present invention, the rotation speed of the turbo compressor 2 is controlled to make the temperature 10 at the cooling liquid outlet (point 4) of the sub-heat exchanger 5 constant. Therefore, if the circulation flow rate of the cooling liquid is constant, the temperature of the cooling liquid inlet (point 3) of the sub-heat exchanger 5 depends on the load of the object to be cooled 6.

When the load of the to-be-cooled body 6 decreases, the temperature of the cooling liquid inlet (point 3) of the subheat exchanger 5 falls, and the temperature of the refrigerant gas returned to the main heat exchanger 3 also decreases. In addition, the inlet temperature of the expansion turbine 4 is also lowered. On the other hand, when the load of the to-be-cooled body 6 decreases, automatic control which lowers the rotation speed of the turbocompressor 2 is performed in order to reduce the refrigerating capacity. When the rotation speed of the turbo compressor 2 decreases, the compression ratio of the refrigerant gas decreases with the flow rate. At this time, the reduction of the inlet temperature of the expansion turbine 4 and the reduction of the expansion ratio occur simultaneously. However, the outlet temperature of the expansion turbine may rise or fall depending on the characteristics of the turbo compressor 2 and the expansion turbine 4 used.

When the outlet temperature of the expansion turbine 4 rises, the temperature of the refrigerant gas inlet (point 1) of the subheat exchanger 5 rises, so that liquid nitrogen (coolant) solidifies in the subheat exchanger 5. There is no case. On the other hand, when the outlet temperature of the expansion turbine 4 decreases, the temperature of the refrigerant gas inlet (point 1) of the subheat exchanger 5 becomes low, so that there is a risk that the coolant solidifies in the subheat exchanger 5. have. In order to avoid solidification of the cooling liquid, it is preferable to reduce the rotation speed of the circulation pump 7 based on the temperature of the refrigerant gas inlet (point 1) of the sub-heat exchanger 5 to reduce the circulation flow rate of the cooling liquid. . When the circulation flow rate of the cooling liquid decreases, the temperature of the cooling liquid rises under the influence of the object to be cooled 6. As a result, in the sub-heat exchanger 5, the refrigerant gas having a lower temperature and the cooling gas having a higher temperature are subjected to heat exchange, so that solidification of the cooling liquid in the sub-heat exchanger 5 can be prevented.

When the load of the to-be-cooled body 6 rises and returns to normal, the rotation speed of the turbo compressor 2 and the rotation speed of the circulation pump 7 are immediately increased to the original value, thereby restoring the circulation flow rate of the cooling liquid. Let's do it. Thereby, the temperature of the cooling liquid in the 2nd waste flow path L2 can be kept in the temperature range which becomes a subcool state, and the temperature of the whole system can be stably maintained. General inverter control is applicable to the rotation speed control of the circulation pump 7.

Example

Hereinafter, the effect of this invention is made clear by an Example. In addition, this invention is not limited to a following example, It can change suitably and can implement in the range which does not change the summary.

(Example 1)

The refrigerator to which the cooling apparatus of the high temperature superconducting apparatus of this invention shown in FIG. 1 was applied was operated until it turned into a steady state. Neon gas was used as the refrigerant gas and liquid nitrogen was used as the cooling liquid. The results of measuring the temperature at each point (measurement point) shown in FIG. 2 are shown in Table 1 below.

As shown in the said Table 1, the temperature of the point 1a shown in FIG. 2 was 64.8K, the temperature of the point 1c was 65.4K, and the temperature of the point 4 was 67.0K. Here, the nitrogen temperature of the subcool state under atmospheric pressure is from a boiling point (about 77K) to a freezing point (about 63K). Therefore, according to the refrigerator of the present invention, the refrigerant gas temperature can be maintained at a temperature at which the cooling liquid does not solidify without using a heater or the like for heating the cooling liquid.

(Example 2)

The Brayton cycle freezer to which the cooling device of the high temperature superconducting apparatus of this invention shown in FIG. 1 was applied was subjected to load change operation. Neon gas was used as the refrigerant gas and liquid nitrogen was used as the cooling liquid.

As a result of varying the load of the HTS device, controlling the rotational speed of the turbo compressor, and controlling the refrigeration capacity of the refrigerator, even when the load of the HTS device varied from 0.7 to 2.5 kW, as shown in FIG. The temperature of the liquid nitrogen outlet (point 4) of the group was constant at 67K. Therefore, according to the cooling apparatus of the high temperature superconducting apparatus of the present invention, even when the load fluctuation operation is performed, the refrigerant gas temperature can be maintained at a temperature at which the cooling liquid does not solidify without using a heater or the like for heating the cooling liquid.

1: freezer (cooling unit)
2: turbo compressor
3: main heat exchanger
4: expansion turbine
5: sub-heat exchanger
5a: first heat exchanger
5b: second heat exchanger
6: coolant
7: circulation pump
10: temperature measuring means
L1: first circulation path (first waste flow path)
L2: second circulation path (second waste flow path)

Claims (8)

A turbo compressor for compressing and circulating refrigerant gas,
A main heat exchanger for cooling the compressed refrigerant gas by heat exchange with the returned refrigerant gas,
An expansion turbine for thermally expanding and expanding the cooled refrigerant gas;
A sub-heat exchanger for heat-exchanging the cryogenic refrigerant gas and the cooling liquid exiting the expansion turbine,
A circulation pump for circulating the coolant between the sub-heat exchanger and the object to be cooled,
Temperature measuring means for measuring a temperature of the cooling liquid;
A first waste flow passage constituting a circulation path for circulating the refrigerant gas after heat exchange in the sub-heat exchanger to the turbo compressor via the main heat exchanger;
A second waste flow passage constituting a circulation path for circulating the cooling liquid after the heat exchange in the sub-heat exchanger to the circulation pump,
The subheat exchanger
A first heat exchange part having a path in which the refrigerant gas flows in parallel, and wherein the refrigerant gas exchanges heat with each other;
And a second heat exchanger configured to exchange heat between the refrigerant gas heat exchanged in the first heat exchanger and the cooling liquid. The method of claim 1,
And the temperature measuring means measures a temperature of the cooling liquid after heat exchange in the sub-heat exchanger. The method of claim 1,
The refrigerant gas is a mixed gas of neon gas, helium gas and neon gas, a mixed gas of hydrogen and neon gas, a mixed gas of hydrogen and helium gas, or a mixed gas in which neon gas, helium gas, or the inert gas is mixed with the mixed gas. Any of the high temperature superconducting apparatus cooling apparatus. The method of claim 1,
And said coolant is liquid nitrogen. As a driving method of the cooling device of the high temperature superconducting apparatus of any one of Claims 1-4,
The operating method of the cooling device of the high temperature superconducting apparatus which controls the temperature of refrigerant gas by the rotation speed of a turbo compressor so that the temperature of the cooling liquid in a 2nd waste channel may become a subcool state. The method of claim 5, wherein
And operating the cooling device of the high temperature superconducting device to lower the rotation speed of the turbo compressor when the temperature of the cooling liquid in the second waste oil passage decreases. The method of claim 5, wherein
And a method of operating a cooling apparatus of a high temperature superconducting device that increases the rotation speed of the turbo compressor when the temperature of the cooling liquid in the second waste passage increases. The method of claim 5, wherein
The circulation flow rate of the said cooling liquid is controlled by the rotation speed of the said circulation pump so that the cooling liquid in a 2nd waste channel may become a subcool state,
A driving method of a cooling device of a high temperature superconducting device that controls the rotation speed of the circulation pump by inverter control.

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