JP5896525B2 - Cooling equipment - Google Patents

Description

  The present invention relates to a cooling facility that includes an air conditioner for cooling a refrigerator, a freezer / refrigerated storage, and the like, and uses a natural refrigerant that is harmless to the global environment.

  A gas circulation type refrigeration apparatus using air or nitrogen gas as a refrigerant gas is known. In the gas circulation refrigeration system, refrigerant gas is adiabatically compressed by a compressor to high temperature and high pressure, cooled by an intermediate cooler, and then adiabatically expanded by an expander to be low temperature and low pressure. The low-temperature and low-pressure refrigerant gas is supplied to a freezer or the like, and the inside of the freezer is cooled by sensible heat of the refrigerant gas. Compared to vapor compression refrigeration equipment that compresses refrigerants such as alternative CFCs and NH3 to high pressure, gas circulation refrigeration equipment does not require high pressure of refrigerant gas, and has the advantage of being safe and not harmful to the environment. An ultra-low temperature refrigerant of 50 ° C. or lower can be made.

  The gas circulation refrigeration system has an open type in which the low-temperature refrigerant gas at the outlet of the expander is opened to a freezer, the refrigerant gas circulation system is closed to the atmosphere, and the low-temperature refrigerant gas and brine at the outlet of the expander are brine-cooled There is a closed type in which heat is exchanged in a vessel. The open type is disclosed in, for example, Patent Document 1, and the closed type is disclosed in, for example, Patent Document 2. FIG. 7 shows the COP (coefficient of performance) of the gas circulation refrigeration apparatus and the vapor compression refrigeration apparatus. Line A shows the COP of the gas circulation refrigeration apparatus, and line B shows the COP of the vapor compression refrigeration apparatus. The COP of the gas circulation refrigeration apparatus is smaller than the vapor compression refrigeration apparatus in a temperature range higher than −55 ° C., but larger than the vapor compression refrigeration apparatus in an ultra-low temperature range of −55 ° C. or less.

  Refrigeration equipment using NH3 as the primary refrigerant and CO2 brine as the secondary refrigerant is widely used in refrigerators as a vapor compression refrigeration equipment that is harmless to the global environment in order to perform freezing of air conditioning and freezing rooms in each room of the building. It has come to be used. This refrigeration apparatus is shown in FIG. In FIG. 8, refrigerators 01 to 04 are provided on each floor of a four-story building 05. The machine room M is provided on the first floor of the building 05, and the NH3 refrigeration apparatus 100 is provided in the machine room M. In the NH3 refrigerating apparatus 100, a compressor 104, a condenser 106, an expansion valve 108, and a CO2 liquefier 110 are provided in a circulation path 102 through which NH3 refrigerant as a primary refrigerant circulates. In the CO2 liquefier 110, the CO2 brine as the secondary refrigerant is cooled with NH3 refrigerant and liquefied.

  In the semi-underground GL of the machine room M, a CO2 liquid reservoir 114 and a liquid pump 116 are provided. The CO2 brine cooled and liquefied by the CO2 liquefier 110 passes through the CO2 circulation path 112 and is stored in the CO2 liquid reservoir 114. Air coolers 120a to 120d are provided in the refrigerators 01 to 04, respectively. The CO2 brine stored in the CO2 liquid reservoir 114 is sent to the air coolers 120a to 120d by the liquid pump 116 via the CO2 circulation path 118. The air coolers 120a to 120d are a casing 122 in which an air flow is formed by the blower 126, a cooling pipe 124 disposed in the casing 122 and connected to the CO2 circulation path 118, and an inlet of the cooling pipe 124. And a flow rate adjusting valve 128 provided in the.

  The air stream is cooled by the cooling pipe 124, and the partially vaporized CO 2 brine returns from the CO 2 circulation path 118 to the CO 2 liquid reservoir 114. The CO 2 gas returned to the CO 2 liquid reservoir 114 is cooled and liquefied by the CO 2 liquefier 110 and returns to the CO 2 liquid reservoir 114.

  The capacity of the compressor 104 of the NH3 refrigerating apparatus 100 needs to be selected in advance so as to meet the maximum total load of the respective refrigerators 01 to 04. On the other hand, in each air cooler 120a-d, the driving | running state differs according to the fluctuation | variation of load from a maximum load driving | operation to a stop state. Therefore, from the viewpoint of the maximum cooling capacity of the compressor 104, the utilization rate of the normal NH3 refrigeration apparatus 100 is low, resulting in inefficient operation, and high initial cost and running cost.

  Patent Document 3 discloses an air conditioner including means for eliminating such a decrease in utilization rate. This air conditioner has two refrigeration units, and when cooling a plurality of cooling chambers, when the cooling load of the cooling chamber requires more than the maximum capacity of the compressor of one refrigeration unit By compensating the cooling capacity with the liquid refrigerant of the other refrigeration apparatus, the maximum capacity at the time of designing the entire refrigeration apparatus can be kept low.

JP 2004-317081 A Japanese Patent Laid-Open No. 10-47829 JP 63-204076 A

  In a refrigerator equipped with a plurality of cooling chambers, the cooling temperature of each cooling chamber has been diversified from C class 10 ° C. or lower to F class −30 ° C. or lower depending on the object to be cooled. For example, in FIG. 8, the refrigerator 01 is C2 class (-2 ° C to -10 ° C), the refrigerators 02 and 03 are F1 class (-20 ° C to -30 ° C), and the refrigerator 04 is C3 class (10 ° C to 10 ° C). -2 ° C). Moreover, the cold storage temperature of the refrigerators 01 to 04 is not constant and is changed according to demand. Therefore, in response to these needs, there is a need for a cooling facility that can operate a plurality of refrigerators having different cooling temperatures efficiently and at low cost.

  However, when the cooling temperatures of the refrigerators 01 to 04 are different, the pressure of the CO2 brine in the gas-liquid two-phase flow at the outlets of the air coolers 120a to 120d is different. That is, in the Class C refrigerator having a high cooling temperature, the evaporation pressure of the CO2 brine is high, and in the Class F refrigerator having a low cooling temperature, the evaporation pressure of the CO2 brine is low. Therefore, when the cooling pipes 124 of the air coolers 120a to 120d are connected to the CO2 circulation path 118 of one system as in the refrigeration apparatus 100 of FIG. 8, the return of the CO2 brine of the class F refrigerator having a low pressure is returned. Will be inhibited. Therefore, it is necessary to adjust the amount of CO2 brine supplied to the air coolers 120a to 120d in accordance with the change in the cooling temperature of the refrigerators 01 to 04, which is complicated control. In addition, the air conditioning apparatus disclosed by patent document 3 cannot respond | correspond to the several refrigerator with different cold storage temperature.

  In view of the problems of the prior art, the present invention uses a closed gas circulation refrigerating apparatus that is safe and harmless to the environment, and NH3 refrigerant that is harmless to the global environment as a primary refrigerant and vapor compression that uses CO2 brine as a secondary refrigerant. The purpose is to realize a cooling facility that can be used at high cost and can be reduced in cost for a plurality of refrigerators having different cooling temperatures in combination with a refrigerator. Another object of the present invention is to realize a cooling facility that can cope with a wide range of cooling temperatures including an ultra-low temperature region and can flexibly cope with fluctuations in the cooling temperature of the refrigerator. It is another object of the present invention to prevent the CO2 brine returning from the air cooler provided in each refrigerator from obstructing the flow of other CO2 brines.

  In order to achieve such an object, the cooling equipment of the present invention is disposed in a closed type gas circulation refrigeration apparatus using air or nitrogen gas as a refrigerant, an NH3 refrigeration apparatus using NH3 as a refrigerant, and a plurality of cooling chambers, respectively. A plurality of air coolers and a plurality of brine supply devices for supplying CO2 brine to the plurality of air coolers, respectively. In this way, by using a closed gas circulation refrigeration apparatus that enables a refrigerant temperature in an ultra-low temperature range of −50 ° C. or less and an NH 3 refrigeration apparatus that has a high cooling capacity in a temperature range of −50 ° C. or more in combination, COP It is possible to cope with a wide range of cooling temperatures including an ultra-low temperature range without lowering.

  A closed-type gas circulation type refrigeration apparatus used in the present invention includes a compressor and an expander coupled to a single output shaft of a drive motor, a magnetic bearing that rotatably supports the output shaft, and a compressor. It has an intermediate cooler that cools the discharged refrigerant gas, and a brine cooler that exchanges heat between the refrigerant gas discharged from the expander and the CO 2 brine. Thus, since the compressor and the expander are connected to a single output shaft, the power required for driving the compressor can be reduced with the power recovered by the expander.

  Further, since the output shaft is rotatably supported by a magnetic bearing, no lubricating oil is required, and air or nitrogen gas that is harmless to the earth is used as a refrigerant, so that ultimate zero emission can be achieved. In addition, cooling to an ultra-low temperature of −55 ° C. or lower is possible with a COP higher than that of the vapor compression refrigeration apparatus. Therefore, it can cope with a wide range of cooling temperatures including an ultra-low temperature region. Moreover, since the refrigerant gas does not become a high pressure of 2 MPa (gauge pressure) or more, it is safe and the pressure resistance strength is not required for the equipment, so that the cost is reduced.

  The NH3 refrigeration apparatus includes an NH3 circulation path and refrigeration cycle components that are provided in the NH3 circulation path and include a CO2 liquefier. The COP of the NH3 refrigerating apparatus is larger than the closed gas circulation refrigerating apparatus at −50 ° C. or higher. Therefore, depending on the set temperature and load of the cooling chamber, it is possible to operate with high efficiency as a whole by operating either or both of them. For example, when the load is 30% or less, only the closed gas circulation refrigeration apparatus is operated, and when the load exceeds 30%, both are operated. Or, during the daytime when the load is high or in the time zone such as the summer, both are operated, and during the time zone such as the nighttime when the load is low, only the closed-type gas circulation refrigeration unit is operated to store the low-temperature CO2 brine. To.

  The air cooler of the present invention includes a cooling pipe through which CO2 brine supplied from a brine supply device flows, and a blower that forms an air flow along the surface of the cooling pipe. Further, the brine supply device of the present invention includes a CO2 brine reservoir that stores a CO2 brine solution cooled by a brine cooler and a CO2 brine solution that is cooled by a CO2 liquefier, and a CO2 brine stored in the CO2 reservoir. And a liquid pump for sending the liquid to the air cooler. The brine cooler and the brine supply device are configured by independent piping systems for each of the plurality of cooling chambers.

  Thus, since the brine cooler and the brine supply device are provided independently for each cooling chamber, the amount and temperature of the CO 2 brine supplied to each cooling chamber can be adjusted for each cooling chamber. Therefore, it is possible to easily control a plurality of cooling chambers having different cooling temperatures to the set temperature, and to flexibly cope with frequent changes in the set temperature of the cooling chamber. Further, even if the pressure of the CO2 brine of each brine cooler is different, the flow of other CO2 brines is not disturbed.

  In the present invention, the brine cooler is arranged in series with respect to the flow path of the refrigerant gas discharged from the expander, and the brine cooler corresponding to the cooling chamber having a lower cooling temperature is located closer to the upstream side portion of the refrigerant gas flow path. It should be arranged. As described above, the brine cooler corresponding to the cooling chamber having the low set temperature is arranged on the upstream side, and the brine cooler corresponding to the cooling chamber having the high set temperature is arranged on the downstream side, so that the refrigerant gas and the CO 2 Heat exchange with brine can be performed with high efficiency. Therefore, a plurality of CO2 brines having different cooling temperatures can be efficiently cooled to a desired temperature range.

  In the present invention, a plurality of cooling chambers each provided with a temperature sensor for detecting a room temperature, and a detected value of the temperature sensor is input, and a blower provided in a closed-type gas circulation refrigeration apparatus, NH3 refrigeration apparatus, and air cooler Control device that controls the flow rate of CO2 brine sent from the CO2 liquid reservoir to the air cooler, brine cooler, and CO2 liquefier, and controls the cooling temperature of a plurality of cooling chambers to a set temperature. It is good to have. Thereby, the temperature of the plurality of cooling chambers having different set temperatures can be controlled efficiently and accurately. For example, if a closed-type gas circulation refrigeration system is operated and low-temperature CO2 brine is stored in the CO2 reservoir, the controller cools the air cooler, brine cooler, and CO2 liquefier from the CO2 reservoir. By controlling the flow rate of the CO2 brine to be sent to, it is possible to control the plurality of cooling chambers to an arbitrary temperature within a range equal to or higher than the temperature of the CO2 brine stored in the CO2 liquid reservoir.

  In the present invention, a plurality of NH3 refrigeration apparatuses can be provided independently for each brine supply apparatus. In such a configuration, the supply system for supplying the CO2 brine to the cooling chamber and the temperature control device for the CO2 brine can be completely independent. Therefore, the cooling temperature of the CO2 brine and the cooling chamber to which the CO2 brine is supplied can be easily and accurately controlled. Further, since a plurality of NH3 refrigeration apparatuses are provided in the cooling chamber according to the number, each NH3 refrigeration apparatus can be reduced in size.

  In the present invention, the NH3 refrigeration apparatus has one NH3 circulation path and a set of refrigeration cycle components provided in the NH3 circulation path, and a plurality of CO2 liquefiers are provided for each brine supply apparatus. The CO2 liquefier may be connected in parallel to the NH3 circuit. Accordingly, since only one NH3 refrigeration apparatus is provided, the facility can be simplified and the cost can be reduced.

  According to the present invention, a closed gas circulation refrigeration apparatus, an NH3 refrigeration apparatus, a plurality of air coolers respectively disposed in a plurality of cooling chambers, and a plurality of CO2 brines supplied to the plurality of air coolers, respectively. This system is equipped with a brine supply device that is harmless to the global environment and can cool multiple cooling chambers with different cooling temperatures, enabling high utilization and low costs, and a wide range of cooling including ultra-low temperatures. It is possible to realize a cooling facility that can respond to the temperature and can flexibly cope with fluctuations in the cooling temperature of the cooling chamber. Further, it is possible to prevent the CO2 brine returning from the air cooler provided in each cooling chamber from obstructing the flow of other CO2 brines.

It is a whole lineblock diagram of the cooling equipment concerning a 1st embodiment of the present invention. It is a partial enlarged view of the cooling facility which concerns on the said 1st Embodiment. It is a block diagram which shows the control apparatus of the cooling equipment which concerns on the said 1st Embodiment. It is explanatory drawing which shows the temperature gradient of the air refrigerant which concerns on the said 1st Embodiment. It is a diagram which shows the fluctuation | variation of the load factor of the cooling facility which concerns on the said 1st Embodiment. It is a whole block diagram of the cooling equipment which concerns on 2nd Embodiment of this invention. It is a diagram which shows COP of a gas circulation refrigerating apparatus and a vapor compression refrigerating apparatus. It is a whole block diagram of the conventional NH3 freezing apparatus.

  Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this embodiment are not intended to limit the scope of the present invention to that unless otherwise specified.

(Embodiment 1)
1st Embodiment of this invention apparatus is described based on FIGS. In FIG. 1, a four-story building 5 has four refrigerators 1 to 4 on each floor, and the cooling facility 10 </ b> A of this embodiment sets the refrigerators 1 to 4 to different cooling temperatures. It is to be cooled. The cooling facility 10A includes a closed-type air circulation refrigeration apparatus 12 that uses refrigerant, four NH3 refrigeration apparatuses 14a to 14d that use NH3 as a refrigerant, and four air cooling units provided in each of the refrigerators 1 to 4, respectively. Devices 16a to 16d and four brine supply devices 18a to 18d for supplying CO2 brine to the respective refrigerators 1 to 4, respectively.

  The closed-type air circulation refrigeration apparatus 12 is provided on the roof of the building 5 or the like. The closed-type air circulation type refrigeration apparatus 12 includes a compression / expansion unit 22, a water-cooled heat exchanger 24, a heat recovery heat exchanger 26, and a brine cooler 28a in a refrigerant circulation path 20 through which air as a refrigerant circulates. To d. The compression / expansion unit 22 includes a centrifugal compressor 30, a drive motor 32, and a turbine expander 34. The compressor 30 and the expander 34 are coupled to a single rotating shaft 32a of the drive motor 32 and rotate coaxially.

  As shown in FIG. 2, a magnetic bearing 36 is used as a bearing that rotatably supports the rotating shaft 32 a between the compressor 30, the drive motor 32, and the casing (not shown) of the expander 34. Therefore, no lubricating oil is required, and the zero-emission refrigeration apparatus uses air as the refrigerant gas. The water-cooled heat exchanger 24 is provided across the compressor discharge side portion of the refrigerant circuit 20 and the cooling water circuit 38. The cooling water circulation path 38 is provided with a cooling water pump 40 that circulates the cooling water in the direction of the arrow and a cooling tower 42 that cools the cooling water heated by the water-cooled heat exchanger 24.

  Four brine coolers 28a to 28d that are independent from each other are provided in series in the discharge-side refrigerant circulation path 20 of the expander 34. The brine coolers 28a to 28d exchange heat between the air discharged from the expander 34 and the CO2 brine to cool the CO2 brine. The heat recovery heat exchanger 26 is provided across the refrigerant circulation path 20 on the outlet side of the water-cooled heat exchanger 24 and the refrigerant circulation path 20 on the outlet side of the brine coolers 28a to 28d.

  In such a configuration, the air used as the refrigerant is adiabatically compressed by the compressor 30 and discharged at a high temperature and high pressure within a discharge pressure range of 2.0 MPa or less. The air discharged from the compressor 30 is primarily cooled by the cooling water circulating in the cooling water circulation path 38 in the water-cooled heat exchanger 24. The primary cooled air is secondarily cooled by the low temperature (−40 ° C. to −50 ° C.) air returned from the brine coolers 28a to 28d by the heat recovery heat exchanger 26. The secondary-cooled air is adiabatically expanded by the expander 34 and discharged as ultra-low temperature (−60 ° C. to −70 ° C.) and low-pressure air below atmospheric pressure. On the other hand, the air returned from the brine coolers 28 a to 28 d is sucked into the suction port of the compressor 30.

  The brine coolers 28a to 28d are arranged in the order of 28c, 28b, 28a, and 28d from the upstream side of the refrigerant circulation path 20. Brine circulation paths 72a to 72d are led to the brine coolers 28a to 28d, respectively. That is, a brine circulation path 72a is installed in the brine cooler 28a, a brine circulation path 46b is installed in the brine cooler 28b, and a brine circulation path 72c is installed in the brine cooler 28c. A brine circulation path 72d is led to 28d. The brine circulation paths 72a to 72d are independent of each other.

  The low-temperature and low-pressure air discharged from the expander 34 is subjected to heat exchange with the CO2 brine gas flowing in the brine circulation paths 72a to 72d in order from the upstream side by the brine coolers 28a to 28d, and the gaseous CO2 brine is cooled and liquefied. Let

  The four NH3 refrigeration apparatuses 14a to 14d are arranged in parallel to the brine supply apparatuses 18a to 18d described later and have the same configuration. Taking the NH3 refrigerating apparatus 14a as an example, the configuration of the NH3 refrigerating apparatuses 14a to 14d will be described. The NH3 refrigerating apparatus 14a includes a compressor 48a, an evaporative condenser 50a, a liquid receiver 52a, an expansion valve 54a, a CO2 liquefier, which are refrigeration cycle components, in an NH3 circulation path 46a through which NH3 circulates as a refrigerant. 56a. The compressor 48a is driven by a drive motor 49a, and the NH3 refrigerant adiabatically compressed by the compressor 48a is cooled and liquefied by the evaporative condenser 50a. The liquefied NH3 refrigerant is temporarily stored in the liquid receiver 52a, then depressurized through the expansion valve 54a, and sent to the CO2 liquefier 56a.

  The CO2 liquefier 56a is provided with a brine circulation path 76a which will be described later, and gaseous CO2 brine is sent from the brine circulation path 76a. In the CO2 liquefier 56a, the NH3 refrigerant cools and liquefies gaseous CO2 brine. The liquefied CO2 brine returns to the CO2 reservoir 64a described later.

  Air coolers 16a to 16d are arranged in the upper portions of the respective coolers 1 to 4, and the configuration of the air coolers 16a to 16d will be described by taking the air cooler 16a as an example. A casing 58a having an opening through which air in the refrigerator 1 can be introduced is provided, and a brine evaporation pipe 60a meanderingly formed in the casing 58a. The brine evaporation pipe 60a is connected to a brine circulation path 66a described later. Moreover, the air blower 62a is provided in the opening exit of the casing 58a, and the air flow along the surface of the brine evaporation pipe | tube 60a is formed by the air blower 62a.

  Liquid CO2 brine is sent from the brine circulation path 66a to the brine evaporation pipe 60a. The liquid CO2 brine exchanges heat with the air flow in the brine evaporation pipe 60a, cools the air flow, and partially vaporizes itself.

  Next, the configuration of the four brine supply devices 18a to 18d will be described by taking the brine supply device 18a as an example. In the vicinity of the building 5, CO2 reservoirs 64a to 64d are provided. A brine circulation path 66a is provided between the CO2 liquid reservoir 64a and the air cooler 16a. The forward path of the brine circulation path 66a for sending the liquid CO2 brine from the CO2 liquid reservoir 64a to the air cooler 16a is connected to the lower liquid reservoir of the CO2 liquid reservoir 64a. A fluid pump 68a and a flow rate adjusting valve 70a are provided on the downstream side of the fluid pump 68a in the forward path.

  A brine circulation path 72 a is provided between the CO 2 liquid reservoir 64 a and the brine cooler 28. The forward path of the brine circulation path 72a for sending gaseous CO2 brine from the CO2 liquid reservoir 64a to the brine cooler 28a is connected to the upper part of the CO2 liquid reservoir 64a. Further, a flow rate adjusting valve 74a is provided in the forward path. Gaseous CO2 brine is sent to the brine cooler 28a from the forward path, and the gaseous CO2 brine is cooled and liquefied by the brine cooler 28a, and returns to the CO2 reservoir 64a. Similarly, the brine circulation path 72b is provided between the CO2 liquid reservoir 64b and the brine cooler 28b, and the brine circulation path 72c is provided between the CO2 liquid reservoir 64c and the brine cooler 28c. 72d is provided between the CO2 reservoir 64d and the brine cooler 28d.

  Further, a brine circulation path 76a is provided between the CO2 liquid reservoir 64a and the CO2 liquefier 56a. A flow rate adjusting valve 76a is provided in the forward path of the brine circulation path 72a for sending gaseous CO2 brine from the CO2 liquid reservoir 64a to the brine cooler 28a. Gaseous CO2 brine is sent to the CO2 liquefier 56a from the forward path, and the gaseous CO2 brine is cooled and liquefied by the CO2 liquefier 56a and returns to the CO2 reservoir 64a.

  In such a configuration, liquid CO2 brine is sent from the CO2 liquid reservoir 64a to the air cooler 16a by the liquid pump 68a, and the liquid CO2 brine is heat-exchanged with the airflow by the brine evaporation pipe 60a to cool the airflow. . The CO2 brine partially vaporized in the brine evaporation pipe 60a returns to the CO2 liquid reservoir 64a. The gaseous CO2 brine in the CO2 reservoir 64a moves by natural circulation to the brine cooler 28a located above the CO2 reservoir 64a. The gaseous CO2 brine that has moved to the brine cooler 28a is cooled by the air refrigerant in the brine cooler 28a, liquefied, and flows down to the CO2 reservoir 64a.

  Similarly, the gaseous CO2 brine in the CO2 reservoir 64a moves by natural circulation to the CO2 liquefier 56a located above the CO2 reservoir 64a. The gaseous CO2 brine moved to the CO2 liquefier 56a is cooled by the NH3 refrigerant in the CO2 liquefier 56a, liquefied, and returns to the CO2 liquid reservoir 64a. The three cooling systems that cool the other refrigerators 2 to 4 operate in the same manner. The brine circulation paths 66a, 72a and 76a connected to the CO2 liquid reservoir 64a and the brine circulation paths belonging to the other three systems of brine supply devices 18a to 18d are provided independently of each other. In FIG. 1 to FIG. 4, in the four systems of cooling devices, the same number is assigned to the same device or part, and the alphabetical characters (a to d) attached after the number belong to which system of cooling device. Has been identified.

  FIG. 3 shows a control system of the cooling facility 10A. The refrigerators 1 to 4 are provided with temperature sensors 82a to 82d for detecting the internal temperature. Detection values of the temperature sensors 82 a to 82 d are input to the control device 80. In the control device 80, based on the detection values of the temperature sensors 82a to 82d, the drive motor 32 of the compression / expansion unit 22, the drive motors 49a to 49d of the compressors 48a to 48d, the drive motors 63a to 63d of the blowers 62a to 62d, and The flow rate adjustment valves 70a to 70d, 74a to 74d, and 78a to 78d are controlled. Thereby, the internal temperature of the refrigerators 1 to 4 is controlled to the set temperature.

  Conventionally, the capacity of the cooling facility 10A such as a compressor has been selected to have a capacity corresponding to the maximum load of each of the refrigerators 1 to 4. On the other hand, at the time of normal use of the refrigerators 1 to 4, it is operated at 30 to 50% of the maximum value of the initially set load. In this embodiment, when the load fluctuation in the air coolers 16a to 16d is about 30% of the maximum load value initially set, only the closed air circulation refrigeration apparatus 12 is operated. That is, CO2 brine is cooled and liquefied by the closed air circulation type refrigeration apparatus 12 and stored in the CO2 reservoirs 64a to 64d. This CO2 brine is sent to the air coolers 16a to 16d of the refrigerators 1 to 4, and the refrigerators 1 to 4 are cooled.

  Each of the refrigerators 1 to 4 is operated at a different cooling load factor. For example, the cooling load factor of the refrigerator 1 (1F) is 30%, the cooling load factor of the refrigerator 2 (2F) is 40%, the cooling load factor of the refrigerator 3 (3F) is 50%, and the refrigerator 4 Assume that the cooling load factor of (4F) is 40%. The refrigerator 1 (1F) having a cooling load factor of 30% cools the CO2 brine by operating only the closed air circulation refrigeration apparatus 12. Therefore, the NH3 refrigeration apparatus 14a is not operated. The refrigerators 2 to 4 (2 to 4F) having a cooling load factor of 40 to 50% use the closed air circulation refrigeration device 12 and the NH3 refrigeration devices 14b to d together to cool the CO2 brine in these operations. .

  In addition, the cooling temperatures of the refrigerators 1 to 4 are also set temperatures different from the C class (10 ° C. or lower) to the F class (−30 ° C. or lower) depending on the object to be cooled. For example, cooler 1 (1F) is cooled to class C2 (-2 ° C to -10 ° C), cooler 2 (2F) and cooler 3 (3F) is cooled to class F1 (-20 ° C to -30 ° C). The storage 4 (4F) is assumed to be set to C3 class (10 ° C to -2 ° C).

  FIG. 4 shows the temperature of the air refrigerant in the refrigerant circuit 20 and the temperature of the CO2 brine in each of the brine coolers 28a to 28d. As shown in FIG. 4, the air refrigerant temperature at the outlet of the expander 34 is −70 ° C., and the air refrigerant temperature at the inlet of the heat recovery heat exchanger 26 is −50 ° C. Cold heat with a temperature difference ΔT = 20 ° C. is distributed to the brine coolers 28a-d to cool and liquefy the CO 2 brine. Heat exchange with a temperature difference ΔT of 20 ° C. is the most efficient.

  For example, in the refrigerator 1 (1F), −10 ° C. CO 2 brine cooled and liquefied by the brine cooler 28a is sent to the air cooler 16a via the CO 2 reservoir 64a. In the refrigerator 4 (4F), a low-temperature CO2 brine liquid at −5 ° C. that has been liquefied by the brine cooler 28d is sent to the air cooler 16d via the CO2 liquid reservoir 64d. In the cooler 2 (2F) and the cooler 3 (3F), the low temperature CO2 brine liquid of −35 ° C. to −30 ° C. cooled and liquefied by the brine coolers 28b and 28c passes through the CO2 liquid reservoirs 64b and 64c. Sent.

  According to this embodiment, in the closed type air circulation type refrigeration apparatus 12, the power required for driving the compressor 30 can be reduced by the power recovered by the expander 34, so that energy is saved. Further, since the output shaft 32a of the drive motor 32 is supported by the magnetic bearing 36, no lubricating oil is required and an air refrigerant that is harmless to the earth is used, so that the ultimate zero emission can be achieved. In addition, the air refrigerant can be cooled to an ultra-low temperature of −55 ° C. or lower with a COP higher than that of the vapor compression refrigeration apparatus, and thus can cope with a wide range of cooling temperatures including an ultra-low temperature region. Further, since the refrigerant gas does not become a high pressure of 2 MPa (gauge pressure) or more, it is safe, and the pressure resistance strength is not required for the equipment, resulting in a low cost.

  Moreover, it can respond to cooling of the wide temperature range including a very low temperature range by using together the closed type air circulation type | mold refrigerating device 12 or NH3 freezing device 14a-d. Moreover, high COP can be maintained as a whole by operating these refrigeration apparatuses in a temperature range where COP is high. Moreover, a normal utilization factor can be raised by using together these refrigeration apparatuses, or using separately. Therefore, equipment costs and running costs can be reduced.

  Moreover, as shown in FIG. 5, in the time zone C where the load factor of the refrigerators 1 to 4 is high, such as in the daytime, summer, and winter, the closed air circulation refrigeration apparatus 12 and the NH3 refrigeration apparatuses 14a to 14d. Use together. On the other hand, in the time zone D in which the load factor of the refrigerators 1 to 4 is low, such as at midnight, the closed air circulation refrigeration apparatus 12 is operated, and the low-temperature CO2 brine is stored in the CO2 reservoirs 64a to 64d. To do. The cold energy stored in the time zone D is used in the time zone C where the load factor is high. As a result, it is possible to flexibly cope with load fluctuations.

  Moreover, since the brine coolers 28a-d and the brine circulation paths 66a-d, 72a-d, and 76a-d are provided independently for each of the four cooling devices that cool the coolers 1 to 4, It becomes easy to adjust the amount and temperature of the CO2 brine supplied to each of the refrigerators 1 to 4 for each refrigerator. Therefore, even when the cooling temperatures of the refrigerators 1 to 4 are different, the adjustment to the cooling temperature is easy, and it is possible to flexibly cope with frequent changes in the cooling temperatures of the refrigerators 1 to 4. Further, since the piping systems of the brine coolers 28a to 28d and the brine supply devices 18a to 18d are independent, even if the CO2 brine pressures of the brine coolers 28a to 28d are different, they do not affect each other. Therefore, it does not hinder the flow of other CO2 brine.

  Further, the brine coolers 28a to 28d are arranged in series with respect to the refrigerant circulation path 20, and the brine cooler corresponding to the cooler having a low cooling temperature is arranged at the upstream side portion of the refrigerant circulation path 20, Each brine cooler 28a-d can efficiently adjust the temperature of the CO2 brine to a desired temperature. Further, the control device 80 drives the drive motor 32 of the compressor 30, the drive motors 49a to 49d of the compressors 48a to 48d, and the drive motors 63a to 63d of the blowers 62a to d based on the detection values of the temperature sensors 82a to 82d. Since the opening degree of the flow rate adjusting valves 70a to d, 74a to d and 78a to d is controlled, the inside temperatures of the plurality of refrigerators 1 to 4 having different cooling temperatures are accurately set to arbitrary temperatures. Can be controlled.

  In addition, since the NH3 refrigeration apparatuses 14a to 14d are separately provided for each of the four systems of the cooling apparatuses, the NH3 refrigeration apparatuses 14a to 14d can be reduced in size, for example, the NH3 refrigeration apparatus can be divided and arranged. In addition, when the refrigerators 1 to 4 have a low load, if the closed-type air circulation type refrigeration apparatus 12 is operated and the low-temperature CO2 brine is stored, this CO2 brine can be used at a high load, and the load changes. It can respond flexibly.

(Embodiment 2)
Next, a second embodiment of the device of the present invention will be described with reference to FIG. In the cooling facility 10B of the present embodiment shown in FIG. 6, the NH3 refrigerating device 84 includes a compressor 88 and its driving motor 89, an evaporative condenser 90, which are refrigeration cycle components, in one NH3 circulation path 86. And a liquid receiver 92 is provided. The downstream NH3 circulation path 86 of the liquid receiver 92 is branched into four branch circulation paths 94a to 94d. Each branch circulation path 94a to 94d is provided with electromagnetic open / close valves 96a to 96d and expansion valves 98a to 98d on the downstream side thereof. Each branch circulation path 94a-d is provided with CO2 liquefiers 56a-d, and brine circulation paths 76a-d are provided between the CO2 liquefiers 56a-d and CO2 liquid reservoirs 64a-d. . The electromagnetic on / off valves 96a to 96d are controlled to open / close by the controller 80.

  In the first embodiment, the control device 80 controls the drive motors 49a to 49d. However, in this embodiment, the control device 80 controls the drive motor 89. In the present embodiment, the NH3 refrigerant branches into the branch circulation paths 94a to 94d on the downstream side of the liquid receiver 92, is decompressed by the expansion valves 98a to 98d, and flows into the CO2 liquefiers 56a to 56d. The opening / closing of the branch circulation paths 94a to 94d and the flow rate of the NH3 refrigerant flowing into the branch circulation paths 94a to 94d are adjusted by controlling the electromagnetic opening / closing valves 96a to 96d by the control device 80. In each CO2 liquefier 56a-d, the NH3 refrigerant cools and liquefies the CO2 brine sent from the brine circulation paths 76a-d. Other configurations and operations are the same as those in the first embodiment.

  According to the present embodiment, in addition to the operational effects obtained in the first embodiment, it is only necessary to provide one NH 3 refrigeration apparatus 84, so that the equipment cost can be reduced compared to the first embodiment. Further, since the installation space for the NH3 refrigerating device 84 can be afforded, it is easy to arrange all the CO2 liquefiers 56a to 56d above the CO2 reservoirs 64a to 64d. Therefore, it becomes easy to return the CO2 brine liquefied by the CO2 liquefiers 56a to 56d to the CO2 reservoirs 64a to 64d by natural circulation.

  According to the present invention, it is possible to realize a cooling facility having a high utilization rate, low cost, and high efficiency for a plurality of cooling chambers that are harmless to the global environment and have different cooling temperatures.

1-4, 01-04 Refrigerator 5,05 Building 10A, 10B Cooling equipment 12 Closed air circulation refrigeration system 14a-d, 84,100 NH3 refrigeration system 16a-d, 120a-d Air cooler 18a-d Brine Supply device 20 Refrigerant circuit 22 Compression / expansion unit 24 Water-cooled heat exchanger 26 Heat recovery heat exchanger 28a-d Brine cooler 30, 48a-d, 88, 104 Compressor 32, 49a-d, 63a-d, 89 Drive motor 32a Rotating shaft 34 Expander 36 Magnetic bearing 38 Cooling water circulation path 40 Cooling water pump 42 Cooling tower 46a-d, 86, 102 NH3 circulation path 50a-d, 90 Evaporating condensers 52a-d, 92 Receiver 54a-d, 98a-d, 108 expansion valve 56a-d, 110 CO2 liquefier 58a-d, 122 casing 60a-d IN evaporating pipe 62a-d, 126 Blower 64a-d, 114 CO2 liquid reservoir 66a-d, 72a-d, 76a-d Brine circulation path 68a-d, 116 Liquid pump 70a-d, 74a-d, 78a-d 128 Flow control valve 80 Controller 82a-d Temperature sensor 94a-d Branch circuit 96a-d Electromagnetic on-off valve 106 Condenser 112, 118 CO2 circuit 124 Cooling pipe

Claims (5)

A closed gas circulation refrigeration apparatus using air or nitrogen gas as a refrigerant, an NH3 refrigeration apparatus using NH3 as a refrigerant, a plurality of air coolers respectively disposed in a plurality of cooling chambers, and the plurality of air coolers. A plurality of brine supply devices for supplying CO2 brine,
The closed-type gas circulation refrigeration apparatus includes a compressor and an expander connected to a single output shaft of a drive motor, a magnetic bearing that rotatably supports the output shaft, and a refrigerant gas discharged from the compressor An intermediate cooler that cools the refrigerant, and a brine cooler that exchanges heat between the refrigerant gas discharged from the expander and the CO2 brine,
The NH3 refrigeration apparatus includes an NH3 circulation path, and a refrigeration cycle component device provided in the NH3 circulation path and including a CO2 liquefier,
The air cooler has a cooling pipe through which CO2 brine supplied from the brine supply device flows, and a blower that forms an air flow along the surface of the cooling pipe,
The brine supply device includes a CO2 brine liquid cooled by the brine cooler and a CO2 liquid reservoir for storing the CO2 brine liquid cooled by the CO2 liquefier, and a CO2 brine liquid stored in the CO2 liquid reservoir. A liquid pump for sending the air to the air cooler,
The brine cooler and the brine supply device are configured by independent piping systems for each of the plurality of cooling chambers.   The brine cooler is arranged in series with the flow path of the refrigerant gas discharged from the expander, and the brine cooler corresponding to the cooling chamber having a lower cooling temperature is arranged at the upstream side portion of the refrigerant gas flow path. The cooling equipment according to claim 1, wherein A temperature sensor for detecting a room temperature is provided in each of the plurality of cooling chambers,
The detection value of the temperature sensor is input to control the driving of the blower provided in the closed gas circulation refrigeration apparatus, the NH3 refrigeration apparatus and the air cooler, and from the CO2 liquid reservoir to the air cooler The control apparatus which controls the flow rate of the CO2 brine sent to the brine cooler and the CO2 liquefier, and controls the cooling temperature of the plurality of cooling chambers to a set temperature. The cooling equipment described.   The cooling facility according to claim 1, wherein a plurality of the NH 3 refrigeration apparatuses are provided independently for each of the brine supply apparatuses.   The NH3 refrigeration apparatus has a single NH3 circulation path and refrigeration cycle components provided in the NH3 circulation path, and a plurality of CO2 liquefiers are provided for each of the brine supply apparatuses. The liquefier is connected to the said NH3 circulation path in parallel, The cooling equipment of Claim 1 characterized by the above-mentioned.

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