JP6842818B2 - Freezing / refrigerating system - Google Patents

Description

The present invention relates to a freezing system or a refrigerating system using a unit cooler (hereinafter collectively referred to as a "freezing / refrigerating system"), and specifically, refrigerating / freezing in which a refrigerant is divided into a plurality of circuits of cooling coils in the unit cooler. Regarding system improvement.

In the secondary refrigeration system that sends the refrigerant cooled to a predetermined temperature to the heat exchanger and the liquid pump type refrigeration system, the conventional manifold (liquid header) is used to connect the unit cooler. By flowing the refrigerant into each circuit of the cooling coil, the refrigerant is evaporated inside the cooling coil, and the heat of vaporization is used to exchange heat between the outside air of the cooling coil and the refrigerant.

By the way, when the refrigerant flows into the unit cooler cooling coil composed of multiple circuits, a pressure loss is generated for each circuit due to the evaporation action (vaporization) that occurs at the same time. When a manifold is used, the pressure loss becomes different for each circuit, it becomes difficult to allow a uniform amount of refrigerant to flow into each circuit, and the heat transfer action on the effective heat transfer surface is reduced.

Specifically, among the circuits of the cooling coil, in one circuit, the refrigerant liquid flows to the outlet, and in another circuit, the overheated gas passes through the outlet, resulting in an uneven flow. As a result, the heat transfer action on the heat transfer surface cannot be effectively utilized, and there arises a problem that the operating efficiency of the refrigeration system is significantly lowered.

Further, when the unit cooler is arranged below the receiver tank (downstream side of the refrigerant), there is a risk that the unevaporated refrigerant liquid stays in the suction pipe unless the refrigerant flow rate is properly controlled. It is difficult to evaporate the liquid refrigerant staying in the suction pipe, and it becomes a resistance to the refrigerant gas that continuously evaporates inside the unit cooler, making it difficult for the refrigerant to pass through the cooling coil. As a result, the pressure inside the unit cooler rises, that is, the refrigerant temperature rises, and the refrigerating capacity is lowered due to the reduction of the temperature difference.

In order to avoid the inconvenience, there is a method of adjusting the flow rate of the refrigerant by a needle valve or the like with reference to a circuit in which the refrigerant flows in from several circuits without evaporation in a plurality of circuits. However, the flow rate adjustment by the needle valve or the manual expansion valve is not a means for detecting the dryness of the cooling coil outlet and ensuring an appropriate flow rate. That is, the heat transfer rate changes due to the temperature difference with the air passing through when heat exchange is performed with the cooling coil, which does not ensure an appropriate superheat range for the pipe length of the cooling coil, but under all operating conditions. It is only a flow rate adjustment to prevent the unevaporated refrigerant liquid from returning at the outlet of the cooling coil.

If a distributor (refrigerant shunt) can be used when the refrigerant flows into each circuit of the cooling coil of the unit cooler, the refrigerant should be evenly distributed to the refrigerant circuit and the heat transfer surface on the refrigerant side should be used effectively. Can be done, and the efficiency of the system can be greatly improved. As a background technique for using such a distributor, for example, there is a refrigeration system described in Patent Document 1 below. By arranging the refrigerant flow passages in the plurality of cooling coil systems in consideration of the temperature distribution, it is possible to eliminate the temperature unevenness of the outlet air, suppress the decrease in the capacity of the refrigerator, and enable energy-saving operation. The purpose is to provide a refrigerant to the inlet side of the refrigerant flow passages of each cooling coil system, and a distributor is connected to each refrigerant flow passage.

Japanese Unexamined Patent Publication No. 2012-172919

By the way, when using a distributor, in the case of the pressure drop type, although it depends on the thermodynamic characteristics of the refrigerant, for example, if a pressure drop of about 50 kPa is not obtained in the nozzle and about 20 kPa is not obtained in the tube, the refrigerant is evenly divided. There is a restriction that it cannot be done. Also, when using a Venturi type distributor, the pressure restoration effect can be obtained after passing through the streamline, but due to its structure, the distributable range is said to be limited to about 20 circuits, so it is limited to small unit coolers. To. In fact, as a result of performing performance tests of various sizes of Venturi type, it was not possible to perform uniform diversion with the required accuracy.

In addition, in the liquid pump type refrigeration system, the pressure of the liquid refrigerant sent by the liquid pump is low as the discharge pressure is only increased by about 150 kPa to 250 kPa with respect to the saturation pressure of the refrigerant itself. The temperature of the supplied liquid refrigerant is close to the evaporation temperature of the refrigerant that evaporates in the heat exchanger. Therefore, for the expansion valve that automatically adjusts the flow rate and the refrigerant that passes through the distributor, the discharge pressure of the pump and the pressure of the liquid column are added, or the pressure is reduced only by subtracting the lift from the discharge pressure of the pump. Since there is only a region, it will pass through the expansion valve and the diversion device, respectively, with the liquid phase unchanged.

At this time, the expansion valve does not expand the throttle, the distributor cannot expect gasification due to the dryness that occurs in front of the nozzle, and the turbulent flow that accompanies the generation of the jet flow when passing through the nozzle does not occur. For this reason, it has not been possible to respond with a design method based on the knowledge up to now.

The present invention focuses on the above points, and an object of the present invention is to evenly distribute the refrigerant to a plurality of circuits of cooling coils in a unit cooler . Another purpose is to maximize the heat transfer surface of the unit cooler, effectively perform the heat transfer action, and improve the operating efficiency of the freezing / refrigerating system.

The present invention is a freezing / refrigerating system that freezes or refrigerates using a unit cooler having a cooling coil composed of a plurality of circuits in a liquid pump type refrigerating / refrigerating system, and is a refrigerant for the unit cooler. The pump means for feeding the refrigerant, the flow rate adjusting means for adjusting the flow rate of the refrigerant sent from the pump means to the unit cooler, and the refrigerant whose flow rate is adjusted by the flow rate adjusting means are distributed to each circuit of the cooling coil of the unit cooler. The flow rate adjusting means includes an expansion valve having an orifice for adjusting the flow rate of the refrigerant sent from the pump means to the unit cooler, and the degree of overheating of the refrigerant on the refrigerant outlet side of the unit cooler. Based on this, a superheat degree controller that controls the flow rate of the refrigerant by the orifice of the expansion valve is provided, and the distributor has the nozzle and a cooling coil composed of a plurality of circuits of the unit cooler having the same length. and a plurality of tubes to be connected to the nozzle to obtain from the measured, and the relationship between the pressure drop of the distributor nozzles and tubing to the unit cooler refrigeration capacity, equivalent shunt can range and equivalents of the relationship A distributor having the refrigerating capacity of the unit cooler to be used and having the inner diameter of the nozzle, the length of the tube, and the inner diameter of the tube, which is the freezing capacity of the unit cooler to be used, is selected from the relationship of the non-dividing region, and the expansion is performed. The nozzle diameter of the valve orifice is larger than the nozzle diameter corresponding to the cross-sectional area obtained from the DD.Will equation based on the refrigerating / refrigerating capacity of the unit cooler and the type of refrigerant, and the flow rate can be adjusted. It is characterized by having a nozzle diameter.

According to one of the main forms, the refrigerating / refrigerating system includes a primary cooling system and a secondary cooling system, and the pump means, the expansion valve, and the distributor are provided in the secondary cooling system. It is characterized by. One other form, to the unit coolers, when a receiver for supplying the coolant is positioned on the lower side, the drop amount of pressure by the distributor and the expansion valve, the said unit cooler receiver The pressurizing capacity of the refrigerant in the pump means is set so that the pressurizing capacity corresponds to the height difference between the pump means and the unit cooler, and the receiver that supplies the refrigerant is located on the upper side. When the pressure is applied, the pressure of the refrigerant in the pump means is increased so that the pressure is obtained by subtracting the pressure corresponding to the height difference between the unit cooler and the receiver from the amount of pressure drop by the expansion valve and the distributor. It is characterized by setting the ability.

According to still another embodiment, the degree of superheat of the refrigerant on the refrigerant outlet side of the unit cooler is detected from the detection results of the temperature sensor and the pressure sensor provided on the refrigerant outlet side of the unit cooler . The above and other objects, features and advantages of the present invention will be clarified from the following detailed description and accompanying drawings.

According to the present invention, the efficiency of the refrigerating / refrigerating system can be improved by uniformly dividing the refrigerant into each circuit of the cooling coil of the unit cooler by an appropriate design of the distributor and by combining the superheat degree control by the expansion valve. Can be planned.

It is a figure which shows the structure of Example 1 of this invention. (A) is an overall view, and (B) is a diagram showing the main part. It is a figure which shows the distributor in the said Example. (A) is a diagram showing the configuration, and (B) and (C) are graphs showing the relationship between the refrigerating capacity and the amount of pressure drop. FIG. 3 is a diagram showing a state of the refrigerant in each circuit of the cooling coil. (A) shows the case of this embodiment, (B) shows the case without a nozzle, and (C) shows the case of the prior art. It is a figure which shows the relationship between the high-low position of a receiver 110 and a unit cooler 150, and a pump pressure. It is a figure which shows the structure of Example 2 of this invention.

Hereinafter, embodiments for carrying out the present invention will be described in detail based on examples.

Example 1 of the present invention will be described with reference to FIGS. 1 and 2. This example is an example in which the present invention is applied to a liquid pump type refrigeration system. FIG. 1A shows the entire refrigeration system 100 of this embodiment. In the figure, on the sending side of the gasified refrigerant in the low receiver 110, the refrigerator (compressor) 114 → the condenser (condenser) 116 → the receiver 118 → the flow rate adjusting valve (needle valve) 120 in that order. A circulation circuit is configured which is connected so that the gasified refrigerant is liquefied and returned to the low receiver 110.

On the other hand, on the delivery side of the liquefied refrigerant in the low receiver 110, the liquid feed pump 130 → the expansion valve 132 → the distributor 140 → the unit cooler 150 → the merging manifold 152 are connected by pipes in this order, and the gasified refrigerant is connected. Is returning to the low receiver 110 again.

A temperature sensor 154 and a pressure sensor 156 are attached to the refrigerant outlet side of the unit cooler 150, and these are connected to the superheat degree controller 158. The control output side of the superheat controller 158 is connected to the expansion valve 132. The superheat degree controller 158 detects the difference from the measured value by the temperature sensor 154, that is, the superheat degree based on the detection result of the refrigerant pressure equivalent temperature by the pressure sensor 156, and the opening degree of the expansion valve 132 is increased based on the result. It is designed to be controlled.

Explaining the general operation of the refrigeration system configured as described above, the gasified refrigerant in the low receiver 110 is compressed by the refrigerator 114 and then condensed by the condenser 116, whereby the liquefied refrigerant is produced. Sent to receiver 118. The refrigerant stored in the receiver 118 is expanded by the flow rate adjusting valve 120 and returned to the low receiver 110.

The liquefied refrigerant in the low receiver 110 is sent by the liquid feed pump 130 to the distributor 140 via the expansion valve 132, whereby the refrigerant is diverted and sent to each cooling coil of the unit cooler 150. The refrigerant that has passed through the unit cooler 150 is gasified, merged by the merging manifold 152, and then returned to the low receiver 110 again. A temperature sensor 154 and a pressure sensor 156 are provided on the refrigerant outlet side of the unit cooler 150, and the detection results thereof are input to the superheat controller 158. The superheat degree controller 158 detects the superheat degree by subtracting the actually measured value read by the temperature sensor 154 from the pressure equivalent saturation temperature converted from the detection result of the pressure sensor 156. Then, the flow rate of the refrigerant is controlled by the expansion valve 132 according to the detected superheat degree, and further, the superheat degree in the unit cooler 150 is controlled.

FIG. 1B shows an enlarged connection portion between the distributor 140 and the unit cooler 150, and the distributor 140 is provided with a nozzle 142 and a tube 144. Each cooling coil of the distributor 140 and the unit cooler 150 is connected by a tube 144 of the same length. In the illustrated example, the unit cooler 150 is provided with five cooling coils, and thus also has five tubes 144.

The present inventor pays attention to the pressure of the liquid feed pump 130 for feeding the pre-cooled refrigerant in the low receiver 110, and the pressure on the refrigerant inlet side of the unit cooler 150 is 100 kPa or more with respect to the saturation pressure of the refrigerant. We have proposed a refrigerant distribution method that favorably distributes the refrigerant by the pressure drop type distributor 140 by securing the liquid pressure so as to be, and the distributor when "R-404A" is used as the refrigerant. It is reported that even if the pressure drop at 140 is 65 kPa, even diversion is possible (for example, Japan Refrigeration and Air Conditioning Society "Frozen" October 2007, Vol. 82, No. 960, P817-P824, "Environment". What is a refrigeration system that supports a friendly cold chain? ”). Generally, in order for the distributor 140 to evenly distribute the refrigerant to each cooling coil, a pressure drop of a certain level or more is required on the nozzle 142 side and the tube 144 side, respectively.

As shown in FIG. 2A, the pressure drop in the distributor 140 is mainly related to the diameter (inner diameter) Dn of the nozzle 142 and the length Lt and the diameter (inner diameter) Dt of the tube 144. FIG. (B) shows an example of the relationship between the pressure drop amount of the nozzle 142 and the refrigerating capacity or cooling capacity (including the case of refrigeration). This graph is an example in the case where the inner diameter Dn = 4.5 mm, and when the pressure drop amount is 35 kPa or less, uniform flow separation of the refrigerant is impossible regardless of the refrigerating capacity. FIG. (C) shows an example of the relationship between the pressure drop amount of the tube 144 and the refrigerating capacity. This graph is an example when the inner diameter is Dt = 3.25 mm (outer diameter is 3/16 inch) and the length is Lt = 1500 mm. When the pressure drop is 15 kPa or less, the refrigerant is equal regardless of the refrigerating capacity. Divergence is impossible.

Next, a design method will be described based on a specific example. For example, it is assumed that carbon dioxide (R-744) is used as the refrigerant and the unit cooler 150 having the specifications shown in Table 1 below is used. In the case of this example, as shown by the arrow, at TD (difference between the refrigerant evaporation temperature in the evaporator and the temperature inside the refrigerator) = 10 ° C., a refrigerating capacity of about 30 kW can be obtained, and the temperature difference of the passing air is It is about 4 ° C.

Next, a calculation example of the orifice of the expansion valve 132 is shown in Tables 2 and 3 below. Table 2 shows the conditions and the DDWILL equation, and Table 3 (A) shows the relationship between the nozzle diameter, cross-sectional area, and mass flow rate of the orifice of the expansion valve 132. Table 3 (B) shows the relationship between the nozzle diameter and the capacity. The coefficient "5020" of the DDWILL equation in Table 2 is a numerical value obtained from an experiment by the inventor Nakayama. Generally, when the refrigerant is ammonia, it is "3880", when it is R22, it is "5470", and when it is methyl chloride, it is "4660". In these tables, for example, looking at the case of the above-mentioned refrigerating capacity of 30 kW, the nozzle diameter of the orifice is 3 mm from Table 3 (B). Since the flow rate is adjusted around this, the nozzle diameter of the orifice should be 4 to 4.5 mm, if a margin is taken into consideration. The difference between the inlet side pressure P1 and the outlet side pressure P2 in the expansion valve 132 is 125 kPa. As described above, even if a general expansion valve is used, by deriving the diameter of the orifice from the DDWILL formula, it is possible to secure the required mass flow rate of the refrigerant even with a very small differential pressure of about 100 kPa. Under this condition, the refrigerant liquid passes through the expansion valve 132 without any change in the state of the liquid phase / gas phase or the change of dryness.

Next, assuming that the distributor 140 shown in FIG. 2 is used, when the refrigerating capacity is 30 kW, the pressure drop amount of the nozzle 142 is 49 kPa (see FIG. 2 (B)), and the pressure drop amount of the tube 144. Is 26 kPa (see FIG. 2 (C)). In each case, the flow separation range exceeds the flow separation impossible range, and good uniform refrigerant flow can be performed. In other words, a distributor having a nozzle diameter of Dn, a tube diameter of Dt, and a tube length of Lt is selected so that the amount of pressure drop in the diversion range in the refrigerating capacity is large. Under this condition, when the refrigerant liquid passes through the nozzle 142 and the tube 144 of the distributor 140, an appropriate pressure drop can be obtained even with a saturated liquid having no gas due to the dryness of the refrigerant.

The situation is shown in FIG. FIG. 6A shows the case of this embodiment, and the expansion valve 132 and the distributor 140 under the above-mentioned conditions are used. According to this, the refrigerant supplied to the distributor 140 at -30 ° C is evenly distributed to each cooling coil of the unit cooler 150 and gasified near the outlet of each cooling coil, and the temperature is around −29 ° C. It has become. The temperature of the air on the inlet side of the unit cooler 150 is -20.3 ° C, while the temperature on the outlet side is -24.6 ° C, and the temperature difference is 4.3 ° C. Since the unit cooler 150 shown in Table 1 has a refrigerating capacity of 30 kW and an air temperature difference of about 4 ° C., the capacity of the unit cooler 150 is almost achieved by designing as in this embodiment. The operation is very efficient.

Distributor 141 of FIG. 3B shows an example in the case where the nozzle 142 is not provided, and in each cooling coil of the unit cooler 150, an excess or deficiency occurs in the circuit in the coil due to the uneven flow of the refrigerant. Therefore, the temperature on the outlet side of each cooling coil varies. Further, since the vaporized refrigerant does not have the ability to cool the air, an ineffective region of the heat transfer surface of the unit cooler 150 is generated, and the cooling capacity of the air is lowered as a whole. It is only cooled to 9 ° C.

FIG. 3C is an example in the case of the conventional manifold system, and in the manifold 151, the refrigerant is not evenly divided as in the case of FIG. 3B. In this example, air at -20.3 ° C is cooled only to -23.3 ° C, and the performance of each cooling coil of the unit cooler 150 is not fully utilized.

As described above, according to the present embodiment, by designing the distributor 140 so that the refrigerant is evenly distributed to each cooling coil of the unit cooler 150, heat exchange (heat transfer action) in the unit cooler 150 is effective. This will be done, and the operating efficiency of the refrigeration system can be improved.

In addition, the expansion valve 132 accurately controls the flow rate according to the degree of superheat, so that the standard and simple control system of the direct expansion system fully demonstrates the refrigerating capacity of the unit cooler in the liquid pump system, and the refrigeration system. System efficiency can be significantly improved from the present. Further, since the liquid pump type automatic operation is performed, it is possible to operate with the optimum dryness by the cooling coil composed of a plurality of circuits of the unit cooler 150 while controlling the degree of superheat.

Furthermore, since it was decided to combine the equal distribution of the refrigerant to each cooling coil of the unit cooler 150 by the distributor 140 and the superheat degree control by the expansion valve 132, the invalid region of the heat transfer surface due to the uneven flow is eliminated. As a whole, it is possible to provide a highly efficient and suitable refrigeration system. That is, as shown in FIG. 3A, since the refrigerant is in a gas-liquid two-phase state in almost the entire length of each circuit of the cooling coil of the unit cooler 150, heat exchange is performed in the entire unit cooler 150. And efficient operation will be performed.

If there is a height difference between the low receiver 110 and the unit cooler 150, it is necessary to determine the capacity of the liquid feed pump 130 in consideration of this difference. In the example of FIG. 4A, the low receiver 110 is located below the unit cooler 150, and the height difference is ha. Therefore, the liquid feed pump 130 is required to have a pressurizing capacity corresponding to the height difference ha in addition to the pressure drop amount by the expansion valve 132 and the distributor 140. For example, assuming that the refrigerant pressure in front of the expansion valve of the unit cooler 150 is 200 kPa, a pressurizing capacity equivalent to 200 + ha, which is the sum of this and the height difference ha, is required at a minimum. In the example of FIG. 4B, the low receiver 110 is located above the unit cooler 150, and the height difference thereof is hb. In this case, since the pressure of the liquid column is added to the discharge pressure of the liquid feed pump 130, if the pressure of the liquid column is subtracted from the discharge pressure of the liquid feed pump 130 and the refrigerant pressure in front of the expansion valve of the unit cooler 150 becomes 200 kPa. Good.

Next, Example 2 of the present invention will be described with reference to FIG. The same reference numerals are used for the same or common components as in the first embodiment. The refrigeration system 200 of the second embodiment includes a primary cooling system 202 and a secondary cooling system 204, and has a configuration in which a heat exchanger 210 is provided between the two. The primary cooling system 202 is composed of a refrigerator 114, a condenser 116, a receiver 118, an expansion valve 232, a temperature sensor 254, a pressure sensor 256, a superheat controller 258, and a heat exchanger 210 on the primary side. The secondary cooling system 204 includes a secondary refrigerant receiver 111, a liquid feed pump 130, an expansion valve 132, a distributor 140, a unit cooler 150, a merging manifold 152, a temperature sensor 154, a pressure sensor 156, a superheat controller 158, and a heat exchanger 210. It is composed of the secondary side of.

The gasified secondary refrigerant in the secondary refrigerant receiver 111 of the secondary cooling system 204 is cooled and liquefied by the primary refrigeration system supplied from the receiver 118 of the primary cooling system 202 in the heat exchanger 210. The refrigerant returns to the secondary refrigerant receiver 110. On the other hand, the primary refrigerant gasified by the heat exchanger 210 is liquefied again by the refrigerator 114 and the condenser 116 and returned to the receiver 118. The operation of the expansion valve 232, the temperature sensor 254, the pressure sensor 256 and the superheat degree controller 258 in the primary cooling system 202 is the operation of the expansion valve 132, the temperature sensor 154, the pressure sensor 156 and the superheat degree controller 158 in the secondary cooling system 204. Similar to the operation, the detection result by the temperature sensor 254 and the pressure sensor 256 at the primary side outlet of the heat exchanger 210 is input to the superheat degree controller 158, and the superheat degree is detected. Then, the flow rate of the refrigerant is controlled by the expansion valve 232 according to the detected degree of superheat. The primary refrigerant, for example, refrigerant such as ammonia or R410A may be used. The secondary refrigerant, e.g., refrigerant such as carbon dioxide or ammonia is used.

Even in such a secondary cooling system, the same effect can be obtained by designing the expansion valve 132 and the distributor 140 of the secondary cooling system 204 in the same manner as in the above embodiment.

The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention. For example, the following are also included.
(1) The above-mentioned embodiment is an example in which the present invention is mainly applied to a refrigerating system, but it can be similarly applied to a refrigerating system and a freezing system. For example, it can be applied to various systems that need to evenly distribute the refrigerant to multiple circuits, such as a plate-type ice maker that uses a shunt for a plurality of plates.
(2) The system configuration shown in the above embodiment is an example, and the present invention can be applied to various known configurations. For example, in the above embodiment, the case where the number of unit coolers is one is shown, but the number of installed units may be increased or decreased as needed. The same applies to the number of distribution cooling coils of the distributor.
(3) The numerical values shown in the above examples are also examples, and may be appropriately changed as necessary.

According to the present invention, the refrigerant is evenly divided into each circuit of the cooling coil of the unit cooler by an appropriate design of the distributor , and the superheat degree control by the expansion valve is combined. Therefore, the refrigerant is combined with the multiple circuits of the cooling coil. It is suitable for a freezing / refrigerating system that evenly distributes.

100: Refrigeration system 110: Low receiver 111: Secondary refrigerant receiver 114: Refrigerator 116: Condenser 118: Receiver 120: Flow control valve 130: Liquid transfer pump 132: Expansion valve 140, 141: Distributor 142: Nozzle 144: Tube 150 : Unit cooler 151: Manifold 152: Confluence manifold 156: Pressure sensor 154: Temperature sensor 158: Superheat controller 200: Refrigeration system 202: Primary cooling system 204: Secondary cooling system 210: Heat exchanger Dn: Nozzle inner diameter Dt: Tube inner diameter Lt: Tube length

Claims (4)

A liquid pump type freezing / refrigerating system that uses a unit cooler with cooling coils composed of multiple circuits to freeze or refrigerate.
Pump means that sends refrigerant to the unit cooler,
A flow rate adjusting means for adjusting the flow rate of the refrigerant sent from the pump means to the unit cooler,
A distributor that distributes the refrigerant whose flow rate has been adjusted by this flow rate adjusting means to each circuit of the cooling coil of the unit cooler.
Is equipped with
The flow rate adjusting means includes an expansion valve having an orifice for adjusting the flow rate of the refrigerant sent from the pump means to the unit cooler, and the expansion valve based on the degree of overheating of the refrigerant on the refrigerant outlet side of the unit cooler. Equipped with an overheat controller that controls the flow rate of refrigerant through an orifice.
The distributor includes a nozzle and a plurality of tubes for connecting a cooling coil composed of a plurality of circuits of the unit cooler to the nozzle with the same length.
The unit to be used is based on the relationship between the pressure drop amount of the nozzle and tube of the distributor and the refrigerating capacity of the unit cooler obtained from the actual measurement, and the relationship between the equal shuntable region and the uniform non- shuntable region in this relationship. Select a distributor that has the refrigerating capacity of the cooler and the inner diameter of the nozzle, the length of the tube, and the inner diameter thereof, which are in the diversion range.
The nozzle diameter of the orifice of the expansion valve is larger than the nozzle diameter corresponding to the cross-sectional area obtained from the DD.Will equation based on the refrigerating / refrigerating capacity of the unit cooler and the type of refrigerant, and the flow rate is adjusted. A freezing / refrigerating system characterized by a possible nozzle diameter. The freezing / refrigerating system includes a primary cooling system and a secondary cooling system.
The freezing / refrigerating system according to claim 1, wherein the pump means, an expansion valve, and a distributor are provided in the secondary cooling system. When the receiver that supplies the refrigerant is located below the unit cooler, the pressure that corresponds to the height difference between the unit cooler and the receiver is the amount of downward pressure generated by the expansion valve and the distributor. The pressurizing capacity of the refrigerant in the pump means is set so that the pressurizing capacity is the sum of the above.
When the receiver that supplies the refrigerant is located above the unit cooler, the pressure corresponding to the height difference between the unit cooler and the receiver is applied from the amount of falling pressure by the expansion valve and the distributor. The freezing / refrigerating system according to claim 1 or 2, wherein the pressurizing capacity of the refrigerant in the pump means is set so as to be the deducted pressurizing capacity. Any one of claims 1 to 3, wherein the degree of superheat of the refrigerant on the refrigerant outlet side of the unit cooler is detected from the detection results of the temperature sensor and the pressure sensor provided on the refrigerant outlet side of the unit cooler. Freezing / refrigerating system described in.

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