JP6405675B2 - Cooling system - Google Patents

Description

  The present invention relates to a cooling device, and more particularly to a cooling device including an expansion valve, an evaporator, and a flow rate adjusting valve that adjusts the amount of refrigerant flowing out of the evaporator.

  Conventionally, a cooling device including an expansion valve, an evaporator, and a flow rate adjusting valve that adjusts the amount of refrigerant flowing out of the evaporator is known (see, for example, Patent Document 1).

  Patent Document 1 discloses an expansion valve that expands liquid refrigerant, a cooler (evaporator) that evaporates the refrigerant expanded by the expansion valve, and an evaporation pressure adjustment valve (flow rate adjustment valve) that adjusts the evaporation pressure of the cooler. And a showcase (cooling device). In the showcase described in Patent Document 1, an operation mode in which the capacity of the cooler is effectively obtained without using the evaporation pressure adjusting valve and the inside of the refrigerator is maintained in the refrigeration temperature zone, and the evaporation pressure adjusting valve is used. The operation mode for maintaining the inside of the refrigerator in the refrigeration temperature zone while suppressing the capacity of the cooler is configured to be switchable.

  Here, the evaporating pressure adjusting valve (EPR) provides a flow resistance (pressure loss) to the refrigerant flowing between the evaporator and the compressor so that the evaporating pressure adjusting valve corresponds to the suction pressure of the compressor. It has the role of increasing the evaporation pressure (evaporation temperature) in the evaporator by the amount of pressure loss that occurs. And the rise in evaporation temperature brings about suppression of cooling capacity. The evaporating pressure adjusting valve has a built-in valve body that opens and closes the throttle, and the evaporating pressure is increased by the amount of the pressing force of the spring that presses the valve body. Further, the spring pressure is set to a predetermined value (fixed value) by the user (operation manager) turning the adjusting screw before operation. Therefore, during operation of the refrigeration cycle apparatus, the evaporation pressure adjusting valve is normally operated in a state where it is set to a fixed value, and the evaporation pressure (evaporation temperature) is kept substantially constant. In addition, in the showcase described in the said patent document 1, it is thought that this general evaporating pressure control valve is used.

JP-A-5-332658

  However, in the showcase described in Patent Document 1, an evaporating pressure adjusting valve whose spring pressure is set to a predetermined value (fixed value) in advance by the user is used. Is not changed. For this reason, even if the proper value of the evaporation temperature of the cooler (evaporator) changes according to the heat load in the warehouse, the operation is continued while the evaporation temperature (evaporation pressure) is kept constant. End up. In particular, in the operating state where the refrigerant heat temperature is too low (the difference between the evaporation temperature and the internal temperature is too large) even though the internal heat load is small and the cooling capacity is to be suppressed, the internal cooling temperature is reduced. There is a problem that it cannot be stably controlled.

  The present invention has been made to solve the above-described problems, and one object of the present invention is to provide a cooling device capable of stably controlling the cooling temperature in accordance with fluctuations in heat load. Is to provide.

In order to achieve the above object, a cooling device according to one aspect of the present invention includes a compressor that compresses a refrigerant, a condenser that condenses the refrigerant, an electronic expansion valve that expands the refrigerant condensed by the condenser, An evaporator that evaporates the refrigerant expanded by the electronic expansion valve, a flow rate adjustment valve that adjusts the flow rate of the refrigerant flowing out of the evaporator according to the opening degree, a refrigerant temperature near the inlet of the evaporator, or a refrigerant inside the evaporator A first refrigerant temperature detector that detects at least one of the temperatures, a second refrigerant temperature detector that detects a refrigerant temperature in the vicinity of the outlet of the evaporator, a refrigerant temperature detected by the first refrigerant temperature detector, and a second refrigerant structure as by controlling the opening of flow control valve based on the degree of superheat of the refrigerant in the vicinity of the outlet of the evaporator based on has been the refrigerant temperature detected by the temperature detection section, controls the evaporation temperature of the refrigerant in the evaporator And a control unit which is, control unit, under the evaporation temperature which is adjusted by the opening control of the flow control valve, the refrigerant temperature and the second refrigerant temperature detecting unit detected by the first refrigerant temperature detector superheat of the refrigerant at the outlet vicinity of the evaporator on the basis of the refrigerant temperature detected by has been configured to control the opening degree of the electronic expansion valve to a predetermined value.

In the cooling device according to one aspect of the present invention, as described above, the evaporation temperature of the refrigerant in the evaporator is controlled by controlling the opening degree of the flow rate adjustment valve based on the degree of superheat of the refrigerant in the evaporator. A configured control unit is provided. As a result, based on the degree of superheat of the refrigerant in the evaporator, while grasping the difference between the cooling capacity of the evaporator being controlled and the actually required cooling capacity, the opening degree of the flow control valve is controlled to achieve proper evaporation. The state of the evaporator can be adjusted to have pressure (evaporation temperature). As a result, since the evaporation temperature of the evaporator can be made to follow according to the fluctuation of the heat load, the cooling temperature can be controlled stably.
Thereby, the state of the evaporator can be accurately grasped based on the degree of superheat of the refrigerant grasped by the first refrigerant temperature detecting portion and the second refrigerant temperature detecting portion. As a result, it is possible to appropriately follow the evaporation temperature of the evaporator in accordance with the accurately grasped fluctuation of the heat load.
As a result, the superheat degree of the refrigerant in the vicinity of the outlet of the evaporator can be further finely controlled under the evaporation temperature appropriately adjusted according to the fluctuation of the heat load. That is, it is possible to optimize the degree of refrigerant evaporation by adjusting the opening of the electronic expansion valve while grasping the degree of refrigerant evaporation in the evaporator whose evaporation temperature has been adjusted. As a result, the evaporator can be used most effectively and efficiently with respect to the evaporation of the refrigerant. As a result, the heat exchange efficiency of the entire evaporator can be maintained high.

  In the configuration further including the first refrigerant temperature detection unit and the second refrigerant temperature detection unit, the first refrigerant temperature detection unit preferably includes an internal refrigerant temperature detection unit that detects a refrigerant temperature inside the evaporator, and is controlled. And the opening of the flow rate adjustment valve based on the degree of superheat of the refrigerant in the vicinity of the outlet of the evaporator based on the refrigerant temperature detected by the internal refrigerant temperature detector and the refrigerant temperature detected by the second refrigerant temperature detector. Based on the refrigerant temperature detected by the internal refrigerant temperature detector and the refrigerant temperature detected by the second refrigerant temperature detector under the evaporation temperature adjusted by the opening degree control of the flow regulating valve. The opening degree of the electronic expansion valve is controlled. If comprised in this way, the superheat degree control of the refrigerant | coolant in the exit of an evaporator can be performed in consideration of the pressure loss inside an evaporator. That is, depending on the size of the evaporator (the length of the heat transfer tube), the refrigerant evaporates inside the evaporator rather than the evaporation temperature near the inlet of the evaporator due to the pressure loss (evaporation pressure drop) in the refrigerant flow path. Sometimes the temperature is low. Therefore, the refrigerant based on the degree of superheat of the refrigerant in the vicinity of the outlet of the evaporator based on the refrigerant temperature (evaporation temperature) inside the evaporator detected by the internal refrigerant temperature detector instead of the refrigerant temperature in the vicinity of the inlet By performing this flow rate control, the superheat degree control of the refrigerant at the outlet of the evaporator can be performed with higher accuracy. As a result, the evaporation completion point of the refrigerant in the evaporator can be positioned more reliably in the vicinity of the outlet of the evaporator, so that almost all refrigerant flow paths from the inlet to the outlet of the evaporator are used as the evaporation region. Can do. As a result, the heat exchange performance (cooling capacity) of the evaporator can be maximized.

  In the cooling device according to the above aspect, each of the plurality of evaporators is preferably connected in parallel to each other, and an electronic expansion valve is provided upstream of each of the evaporators. The controller is provided corresponding to each of the evaporators, and the control unit controls the opening degree of the flow rate adjusting valve corresponding to each of the evaporators based on the degree of superheat of the refrigerant included in each evaporator, thereby The evaporating temperature is individually controlled. If comprised in this way, the whole cooling device can be operation-controlled so that it may become the evaporation pressure (evaporation temperature) suitable for each, grasping | ascertaining the cooling capability requested | required for every evaporator individually. Further, since the cooling temperature for each evaporator can be stably controlled, the cooling device can be efficiently operated.

  In the configuration in which the flow rate adjusting valve is provided corresponding to each of the plurality of evaporators, preferably, the flow rate adjusting valve is provided in parallel with the flow rate adjusting valve, bypassing the flow rate adjusting valve, the outlet side of the evaporator and the suction of the compressor A bypass passage that connects to the side of the plurality of evaporators, and the control unit bypasses the evaporator when the evaporation temperature of the refrigerant corresponding to the refrigerant passage provided with the bypass passage is the lowest. The degree of superheat of the refrigerant corresponding to each of the evaporators other than the evaporator having the lowest evaporation temperature in the state where the refrigerant is circulated through the bypass flow path without flowing the refrigerant through the flow rate adjusting valve parallel to the flow path. The evaporating temperature of the refrigerant for each evaporator is individually controlled by controlling the opening degree of the flow rate adjusting valve based on the above. With this configuration, when the evaporation temperature of a specific evaporator is the lowest among the plurality of evaporators, an unnecessary throttle (flow resistance) by the flow rate adjusting valve is formed in the refrigerant flow path on the downstream side of the evaporator. It can be avoided. Therefore, even when operating a cooling device with a mixture of evaporators with different cooling capacities, it is possible to suppress the load on the compressor (increase in compression ratio) due to unnecessary restriction (circulation resistance). can do.

  According to the present invention, as described above, it is possible to provide a cooling device capable of stably controlling the cooling temperature in accordance with the fluctuation of the thermal load.

It is the figure which showed schematic structure of the cooling device by 1st Embodiment of this invention. It is the block diagram which showed the control structure of the cooling device by 1st Embodiment of this invention. It is the figure which showed schematic structure of the cooling device by 2nd Embodiment of this invention. It is the block diagram which showed the control structure of the cooling device by 2nd Embodiment of this invention. It is the figure which showed schematic structure of the cooling device by 3rd Embodiment of this invention. It is the block diagram which showed the control structure of the cooling device by 3rd Embodiment of this invention. It is the figure which showed schematic structure of the cooling device by 4th Embodiment of this invention. It is the block diagram which showed the control structure of the cooling device by 4th Embodiment of this invention.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below with reference to the drawings.

(First embodiment)
With reference to FIG. 1 and FIG. 2, the structure of the cooling device 100 by 1st Embodiment of this invention is demonstrated.

As shown in FIG. 1, the cooling device 100 according to the first embodiment of the present invention is configured to be able to form a predetermined refrigeration cycle using a CO ₂ refrigerant. Specifically, the cooling device 100 includes a compressor 10, a gas cooler (heat radiator) 20, an electronic expansion valve 30a (30b and 30c), an evaporator 40a (40b and 40c), and a refrigerant pipe (mainly, connecting them). A discharge pipe 1, a liquid pipe 2 and a suction pipe (gas pipe) 3) are provided. The gas cooler 20 is an example of the “condenser” in the present invention, and the electronic expansion valves 30a to 30c are examples of the “expansion valve” in the present invention.

  The cooling device 100 is installed to maintain a refrigerated warehouse 105 for storing articles (not shown) at a predetermined temperature. Here, the refrigerated warehouse 105 is a refrigerated warehouse having a plurality of accommodation areas (accommodations) A to C (indicated by two-dot chain lines) that can be maintained at different temperatures (refrigeration temperature or freezing temperature). Therefore, the cooling device 100 includes the evaporators 40a to 40c for cooling the objects to be cooled (articles) stored in the storage areas A to C of the refrigerated warehouse 105, respectively. The evaporator 40 a is provided mainly for cooling the storage area A in the refrigerated warehouse 105. The evaporator 40b mainly cools the storage area B, and the evaporator 40c is provided to mainly cool the storage area C.

  Moreover, the evaporators 40a-40c are mutually connected in parallel by the low voltage | pressure side of one refrigeration cycle (refrigerant circuit which comprises the cooling device 100). That is, the liquid pipe 2 on the high pressure side is branched into three systems of liquid pipes 2a, 2b and 2c. An electronic expansion valve 30a and an evaporator 40a are connected in series to the liquid pipe 2a, and an electronic expansion valve 30b and an evaporator 40b are connected in series to the liquid pipe 2b. An electronic expansion valve 30c and an evaporator 40c are connected in series to the liquid pipe 2c. Then, the refrigerant pipes 5 a to 5 c connected to the downstream side of each of the evaporators 40 a to 40 c on the low pressure side merge together to become the suction pipe 3, and the suction pipe 3 is connected to the compressor 10.

  Each functional component constituting the cooling device 100 will be briefly described. The compressor 10 has a role of compressing the sucked gas refrigerant and discharging it to the high pressure side (discharge pipe 1). The compressor 10 is an inverter-controlled compressor that can control the refrigerant discharge amount based on the rotational speed control. The gas cooler 20 has a function of cooling the superheated gas refrigerant flowing through the inside using outside air (air) blown by the blower 21. The refrigerant condensed (liquefied) in the gas cooler 20 flows through the liquid pipe 2a and flows into the electronic expansion valve 30a.

  The electronic expansion valve 30a has a role of expanding and supplying the refrigerant cooled (liquefied) by the gas cooler 20 to the evaporator 40a. Further, the electronic expansion valve 30a opens and closes the valve mechanism using the driving force of a stepping motor driven by pulse control. Further, the flow rate of the refrigerant flowing into the evaporator 40a is controlled according to the opening degree of the electronic expansion valve 30a. In addition, the liquid refrigerant expanded and throttled by the electronic expansion valve 30a flows into the evaporator 40a through the refrigerant pipe 4a while being in a gas-liquid two-phase state.

  The evaporator 40a has a function of evaporating the gas-liquid two-phase refrigerant supplied from the electronic expansion valve 30a. The refrigerant evaporates while obtaining latent heat of vaporization when flowing through the evaporator 40a, and at this time, heat is taken away from the air flowing through the storage area A. Although not shown in detail, the evaporator 40a is a fin-and-tube type air heat exchanger in which a refrigerant flows through the heat transfer tube. That is, the evaporator 40a is fixed to the outer peripheral wall of the heat transfer tube group that reciprocates between a pair of end plates (end plates) and the heat transfer tube group arranged in parallel, and has a plurality of fins arranged at equal pitch intervals. And a member. In addition, the refrigerant after evaporation in the evaporator 40 a is in a gas state containing a large amount of gas phase, is circulated in the order of the refrigerant pipe 5 a and the suction pipe 3, and is returned to the compressor 10.

In the cooling device 100, the refrigerant (CO ₂ ) discharged from the compressor 10 is discharged from the discharge pipe 1, the gas cooler 20, the liquid pipes 2a (2b and 2c), the electronic expansion valve 30a (30b and 30c), and the evaporator 40a (40b). 40c), the refrigerant pipes 5a (5b and 5c), and the suction pipe 3 are passed in the direction of the arrow P in this order, and the cycle of returning to the compressor 10 again is repeated.

  In addition, as shown in FIG. 2, the cooling device 100 is provided with a control unit 70 for performing operation control of the compressor 10 and the electronic expansion valves 30 a to 30 c. In addition, air temperature sensors 91a to 91c for detecting the respective current temperatures are provided in the accommodating areas A to C, respectively. The cooling device 100 is configured such that the respective capacities (cooling capacities) of the evaporators 40a to 40c are individually controlled by the control unit 70 based on the detection results of the air temperature sensors 91a to 91c.

  Specifically, as shown in FIG. 1, the respective capacities of the evaporators 40 a to 40 c are adjusted according to the current cooling load with respect to the set temperature in the refrigerated warehouse 105. When the current temperature is higher than the set temperature of each of the storage areas A to C, each of the evaporators 40a to 40c is controlled by the rotation speed control of the compressor 10 and the opening control of each of the electronic expansion valves 30a to 30c. Operation control for increasing the cooling capacity is performed. On the other hand, when the difference between the set temperature (target value) of each of the storage areas A to C and the current temperature is small, the operation of gradually decreasing the cooling capacity of each of the evaporators 40a to 40c according to the difference. Control is performed.

  In this case, the evaporator 40a plays a role of maintaining the storage area A in a low temperature range (for example, a refrigeration temperature of around −20 ° C.). The evaporator 40b plays a role of maintaining the storage area B in an intermediate temperature range (for example, a refrigeration temperature range of about −5 ° C. to about 0 ° C.). The evaporator 40c plays a role of maintaining the accommodation region C in a high temperature region (for example, a range where the refrigeration temperature is about 5 ° C. or more and about 8 ° C. or less). That is, the evaporator 40a is required to have a relatively large cooling capacity, while the evaporators 40b and 40c are required to have a smaller cooling capacity in this order with respect to the evaporator 40a. Therefore, the capacities of the evaporators 40a to 40c are controlled so as to exhibit a cooling capacity corresponding to each set temperature range (required cooling load).

  Note that the correspondence relationship between the accommodation regions A, B, and C described above and the set temperature (low temperature region, middle temperature region, and high temperature region) is an example, and this correspondence relationship can be changed. For example, since the types of articles stored in the refrigerated warehouse 105 change depending on the season, the individual correspondence between the storage areas A to C and the low temperature range to the high temperature range is also changed. In addition, a certain range is also provided for the temperature setting value for each storage area corresponding to the type of article to be stored. This also varies the cooling load on the evaporators 40a to 40c individually. That is, it is desirable that the evaporation temperature (evaporation pressure) of the refrigerant included in each of the evaporators 40 a to 40 c is automatically and frequently adjusted according to the change in the usage mode of the refrigerated warehouse 105. In the following, the evaporator 40a is responsible for the low temperature range (around −20 ° C.), the evaporator 40b is responsible for the medium temperature range (about −5 ° C. to about 0 ° C.), and the evaporator 40c is the high temperature range (about 5 ° C.). The description will be given by taking as an example a mode that bears about 8 ° C. or less.

  In the cooling device 100, the rotation speed (operating frequency) of the compressor 10 is set to a command of the control unit 70 (see FIG. 2) so that it is close to the target evaporation temperature Tga required for the evaporator 40a that requires the most cooling capacity. Control based on. That is, the low pressure (evaporation pressure) is adjusted by increasing or decreasing the rotation speed of the compressor 10. Thereby, the evaporating temperature Tea of the evaporator 40a becomes the vicinity of the target evaporating temperature Tga, and the refrigerating cycle state which can cool the accommodating area | region A is formed. And the optimal flow volume of the refrigerant | coolant inside the evaporator 40a is ensured by the opening degree control of the electronic expansion valve 30a. At the same time, the superheat degree H1a of the refrigerant gas at the outlet of the evaporator 40a is kept within a certain range. In this manner, the evaporator 40a exhibits the cooling ability for maintaining the storage area A in the low temperature range.

  On the other hand, with respect to the evaporator 40b that does not require a cooling capacity as compared with the evaporator 40a, the evaporation pressure (evaporation temperature) is too low with the rotation speed of the compressor 10 adjusted based on the evaporator 40a. Therefore, control is performed to raise the evaporation temperature Teb of the evaporator 40b in accordance with the set temperature (about −5 ° C. or more and about 0 ° C. or less) of the accommodation region B that is relatively higher than the accommodation region A.

  Here, in 1st Embodiment, as shown in FIG. 1, the flow volume adjustment valve 52 is provided in the refrigerant | coolant piping 5b downstream from the evaporator 40b. The flow rate adjustment valve 52 is disposed between the evaporator 40 b and the compressor 10. The flow rate adjusting valve 52 opens and closes the valve mechanism using the driving force of the stepping motor driven by pulse control. Further, the flow rate of the refrigerant flowing out of the evaporator 40b is controlled according to the opening degree of the flow rate adjusting valve 52.

  The flow rate adjustment valve 52 squeezes the refrigerant passing therethrough and applies a pressure loss (pressure difference). That is, the evaporation pressure in the evaporator 40b on the upstream side by the pressure loss caused by the flow rate adjustment valve 52 with respect to the low pressure (intake pressure) determined by the rotation speed of the compressor 10 with the evaporator 40a as a reference. (Evaporation temperature Teb) is raised. Then, in a state where the evaporation temperature Teb of the evaporator 40b is raised by narrowing the flow rate adjustment valve 52, the opening degree control (fine adjustment control of the superheat degree H1b) of the electronic expansion valve 30b related to the evaporator 40b is performed. Thereby, the cooling capacity for maintaining the storage area B in the intermediate temperature range (about −5 ° C. or more and about 0 ° C. or less) is exhibited in the evaporator 40b.

  In the first embodiment, the refrigerant temperature sensor 81b is provided in the refrigerant pipe 4b upstream of the evaporator 40b and immediately after the electronic expansion valve 30b. A refrigerant temperature sensor 82b is provided in the refrigerant pipe 5b downstream of the evaporator 40b and between the evaporator 40b and the flow rate adjustment valve 52. The refrigerant temperature sensor 81b has a function of detecting the refrigerant temperature T1b in the vicinity of the inlet portion flowing into the evaporator 40b. The refrigerant temperature sensor 82b has a function of detecting the refrigerant temperature T2b in the vicinity of the outlet that flows out of the evaporator 40b. The refrigerant temperature sensors 81b and 82b are examples of the “first refrigerant temperature detection unit” and the “second refrigerant temperature detection unit” of the present invention, respectively.

  Thereby, the evaporation temperature Teb of the evaporator 40b is grasped in a control manner based on the refrigerant temperature T1b detected by the refrigerant temperature sensor 81b. Therefore, the cooling capacity required for the evaporator 40b is calculated by the control unit 70 (see FIG. 2) based on the difference between the set temperature of the storage area B and the current temperature. A target evaporation temperature Tgb corresponding to the calculated cooling capacity is set. Then, the evaporation temperature Teb is adjusted so that the difference between the target evaporation temperature Tgb and the current evaporation temperature Teb of the evaporator 40b is zero. That is, when the cooling capacity of the evaporator 40b is excessive, the control proceeds in the direction of increasing the evaporation temperature Teb.

  At this time, first, the degree of opening of the electronic expansion valve 30b is controlled, and the flow rate of the refrigerant flowing into the evaporator 40b is adjusted to near an appropriate amount. Further, a predetermined amount of superheat H1b is generated in the vicinity of the outlet of the evaporator 40b according to the opening of the electronic expansion valve 30b. The degree of superheat H1b is grasped based on the refrigerant temperature T1b detected by the refrigerant temperature sensor 81b and the refrigerant temperature T2b detected by the refrigerant temperature sensor 82b. And the opening degree of the flow regulating valve 52 is further controlled based on the superheat degree H1b of the refrigerant. Thereby, the evaporation temperature Teb is brought close to a level commensurate with the cooling capacity required for the evaporator 40b. In this case, the evaporation temperature Teb is larger (higher) than the evaporation temperature Tea.

  Note that when the flow rate adjustment valve 52 is controlled to be throttled (decreasing the opening), the evaporation temperature Teb is raised. That is, as the opening degree of the flow rate adjustment valve 52 decreases, the refrigerant is further throttled and the pressure loss (pressure difference) increases. Since the refrigerant pressure (low pressure) in the suction pipe 3 is determined on the compressor 10 side, the evaporation pressure (evaporation temperature Teb) in the evaporator 40b is increased by an increase in pressure loss (pressure difference). Since the evaporation temperature Teb is increased, the temperature difference during heat exchange with the air side in the evaporator 40b becomes smaller. Since the refrigerant in the evaporator 40b is evaporated while maintaining the gas-liquid two-phase state for a longer time, the superheat degree H1b at the outlet of the evaporator 40b is gradually reduced.

  Further, when the flow rate adjustment valve 52 is controlled to open (increase the opening), the evaporation temperature Teb is lowered. That is, as the opening degree of the flow regulating valve 52 increases, the throttle of the refrigerant is loosened, and the pressure loss (pressure difference) decreases. Further, the decrease in pressure loss (pressure difference) reduces the evaporation pressure (evaporation temperature Teb) in the evaporator 40b. Since the evaporation temperature Teb is lowered, the temperature difference during heat exchange with the air in the evaporator 40b becomes larger. Therefore, since the refrigerant in the evaporator 40b finishes the vapor-liquid two-phase state in a shorter time and completes the evaporation, the degree of superheat H1b at the outlet of the evaporator 40b gradually increases.

  In this way, the evaporation temperature Teb is brought closer to the target evaporation temperature Tgb by repeatedly increasing or decreasing the opening degree of the flow rate adjusting valve 52 with reference to the degree of superheat H1b.

  In the first embodiment, the degree of superheating H1b of the refrigerant in the vicinity of the outlet of the evaporator 40b (= refrigerant temperature T2b−refrigerant temperature T1b) based on the evaporation temperature Teb adjusted by the opening degree control of the flow regulating valve 52. The opening degree of the electronic expansion valve 30b is finely controlled so that becomes a predetermined value. Also at this time, the degree of superheat H1b is grasped as needed based on the refrigerant temperature T1b detected by the refrigerant temperature sensor 81b and the refrigerant temperature T2b detected by the refrigerant temperature sensor 82b.

  Note that the opening degree control of the flow rate adjustment valve 52 raises or lowers the evaporation temperature Teb as described above, but causes a temporary increase or decrease in the superheat degree H1b. However, the degree of superheat H1b is finally maintained by controlling the opening of the electronic expansion valve 30b that controls the flow rate of the refrigerant flowing into the evaporator 40b. Thus, with respect to the evaporator 40b, the superheat degree H1b is finely adjusted by adjusting the opening degree of the electronic expansion valve 30b while adjusting the rough level of the evaporation temperature Teb by controlling the opening degree of the flow rate adjusting valve 52. . Thereby, the cooling capacity of the evaporator 40b is finely adjusted in a state where the target evaporation temperature Tgb and the superheat degree H1b are stably maintained. Therefore, the storage region B is stably maintained in the middle temperature range.

  Further, the same configuration and control as in the case of performing the capacity control of the evaporator 40b is applied to the evaporator 40c that does not require further cooling capacity than the evaporator 40b. That is, control for increasing the evaporation pressure (evaporation temperature Tec) of the evaporator 40c in accordance with the set temperature (about 5 ° C. or more and about 8 ° C. or less) of the storage area C is similarly performed.

  That is, in the first embodiment, the flow rate adjustment valve 53 is provided in the refrigerant pipe 5c on the downstream side of the evaporator 40c. The flow rate adjustment valve 53 is disposed between the evaporator 40 c and the compressor 10. Further, the flow rate of the refrigerant flowing out of the evaporator 40c is controlled according to the opening degree of the flow rate adjusting valve 53. A refrigerant temperature sensor 81c is provided in the refrigerant pipe 4c, and a refrigerant temperature sensor 82c is provided in the refrigerant pipe 5c between the evaporator 40c and the flow rate adjustment valve 53. The refrigerant temperature sensor 81c detects the refrigerant temperature T1c in the vicinity of the inlet flowing into the evaporator 40c, and the refrigerant temperature sensor 82c has a function of detecting the refrigerant temperature T2c in the vicinity of the outlet flowing out of the evaporator 40c. The refrigerant temperature sensors 81c and 82c are examples of the “first refrigerant temperature detector” and the “second refrigerant temperature detector” of the present invention, respectively.

  The role of the flow rate adjustment valve 53 is the same as that of the flow rate adjustment valve 52. In the evaporator 40c, the evaporation pressure (evaporation temperature Tec) is further increased with respect to the evaporators 40a and 40b by restricting the flow rate adjusting valve 53 while referring to the degree of superheat H1c corresponding to the opening degree of the electronic expansion valve 30c. The In the evaporator 40c, the opening control of the electronic expansion valve 30c (fine adjustment control of the superheat degree H1c related to the evaporator 40c) is further performed in a state where the evaporation temperature Tec is raised by restricting the flow rate adjustment valve 53. Thereby, the cooling capacity for maintaining the storage area C in a high temperature range (about 5 ° C. or more and about 8 ° C. or less) is exhibited in the evaporator 40c.

  Also in this case, the superheat degree H1c (= refrigerant temperature T2c−refrigerant temperature T1c) of the refrigerant in the vicinity of the outlet of the evaporator 40c is predetermined based on the evaporation temperature Tec adjusted by the opening degree control of the flow rate adjusting valve 53. The opening degree of the electronic expansion valve 30c is finely controlled so as to be a value. At this time, the superheat degree H1c is grasped as needed based on the refrigerant temperature T1c detected by the refrigerant temperature sensor 81c and the refrigerant temperature T2c detected by the refrigerant temperature sensor 82c.

  While the opening degree control of the flow rate adjustment valve 53 increases or decreases the evaporation temperature Tec, it temporarily causes a temporary increase or decrease in the superheat degree H1c. However, the degree of superheat H1c is finally maintained by controlling the opening of the electronic expansion valve 30c that controls the flow rate of the refrigerant flowing into the evaporator 40c. As described above, the superheat degree H1c is finely adjusted by controlling the opening degree of the electronic expansion valve 30c while adjusting the rough level of the evaporation temperature Tec by controlling the opening degree of the flow rate adjusting valve 53 in the evaporator 40c. . Thereby, the cooling capacity is finely adjusted in a state where the target evaporation temperature Tgc and the superheat degree H1c are stably maintained. Therefore, the storage region C is stably maintained in a high temperature region.

  In the first embodiment, as shown in FIG. 1, a flow rate adjusting valve 51 is provided in the refrigerant pipe 5a downstream of the evaporator 40a in the refrigerant circuit to which the evaporator 40a is connected. Further, the flow rate of the refrigerant flowing out of the evaporator 40a is controlled according to the opening degree of the flow rate adjusting valve 51. A refrigerant temperature sensor 81a is provided in the refrigerant pipe 4a, and a refrigerant temperature sensor 82a is provided in the refrigerant pipe 5a between the evaporator 40a and the flow rate adjustment valve 51. The refrigerant temperature sensor 81a detects the refrigerant temperature T1a in the vicinity of the inlet flowing into the evaporator 40a, and the refrigerant temperature sensor 82a has a function of detecting the refrigerant temperature T2a in the vicinity of the outlet flowing out of the evaporator 40a. The refrigerant temperature sensors 81a and 82a are examples of the “first refrigerant temperature detection unit” and the “second refrigerant temperature detection unit” of the present invention, respectively.

  Therefore, for example, when the storage area A is kept in a low temperature range (around −20 ° C.) and there are few objects to be cooled (articles) and the heat load is small, the flow rate adjusting valve 51 is also related to the evaporator 40a. The opening degree control is performed. That is, similarly to the evaporators 40b and 40c, the cooling capacity of the evaporator 40a is also suppressed. Also in this case, the superheat degree H1a of the refrigerant in the vicinity of the outlet of the evaporator 40a (= refrigerant temperature T2a−refrigerant temperature T1a) under the evaporation temperature Tea adjusted by the opening degree control of the flow rate adjusting valve 51 based on the superheat degree H1a. ) Is finely controlled so that the opening of the electronic expansion valve 30a becomes a predetermined value. Also at this time, the degree of superheat H1a is grasped as needed based on the refrigerant temperature T1a detected by the refrigerant temperature sensor 81a and the refrigerant temperature T2a detected by the refrigerant temperature sensor 82a.

  As described above, regarding the evaporator 40a as well, first, the opening degree control of the electronic expansion valve 30a is performed, and the flow rate of the refrigerant flowing into the evaporator 40a is adjusted to near an appropriate amount. The rough level of the evaporation temperature Tea is adjusted by opening control of the flow rate adjustment valve 51 based on the degree of superheat H1a corresponding to the opening of the electronic expansion valve 30a. Further, the superheat degree H1a is finely adjusted by the subsequent opening degree control of the electronic expansion valve 30a in a state where the evaporation temperature Tea is adjusted in the vicinity of the target evaporation temperature Tga. Thereby, the cooling capacity of the evaporator 40a is suppressed in a state where the target evaporation temperature Tga and the superheat degree H1a are stably maintained. Further, the cooling capacity of the evaporator 40a is finely adjusted. Therefore, the accommodation region A is stably maintained in a low temperature region with a small thermal load.

  Since the flow rate adjustment valve 51 is provided downstream of the evaporator 40a, the storage area A can be maintained not only in the low temperature range but also in the middle temperature range or the high temperature range. That is, in the cooling device 100, the cooling capacity of the evaporator 40a is greatly reduced by restricting the flow rate adjusting valve 51, while the flow rate adjusting valve 52 or the flow rate adjusting valve 53 is fully opened (pressure loss is minimized). Thus, the refrigerant pressure (evaporation pressure (evaporation temperature Teb or evaporation temperature Tec)) in the evaporator 40b or the evaporator 40c can be reduced. That is, the evaporation temperature Teb and / or the evaporation temperature Tec can be lowered below the evaporation temperature Tea. Accordingly, it is possible to set the storage area A to the middle temperature range and set the storage areas B and C to the low temperature range to use the refrigerated warehouse 105.

  As described above, the refrigerated warehouse 105 includes the cooling device 100 in which the evaporators 40a to 40c that require different cooling capacities between the storage areas A to C are connected in parallel to one refrigeration cycle (refrigerant circuit). Yes. In the cooling device 100, the evaporation pressure (cycle low pressure) of the evaporator 40a that requires the most cooling capacity (heat load) is determined by controlling the rotation speed of the compressor 10, while the flow rate adjusting valve 52 is used to determine the evaporator. The evaporation pressure (evaporation temperature Teb) of 40b is independently controlled, and the evaporation pressure (evaporation temperature Tec) of the evaporator 40c is uniquely controlled using the flow rate adjusting valve 53. Furthermore, when the set temperature (heat load) of the storage area A is small, the evaporation pressure (evaporation temperature Tea) of the evaporator 40a can be independently controlled using the flow rate adjustment valve 51. Therefore, not only the seasonal variation of the storage contents of the article but also the case where the environment where the refrigerated warehouse 105 is installed causes a daily fluctuation, the cooling device 100 is operated following the daily fluctuation. Thereby, it is comprised so that the cooling temperature (internal temperature) always requested | required may be stably maintained regarding any of storage area | region AC.

  Moreover, as a control structure of the cooling device 100, as shown in FIG. 2, in addition to the control part 70 which consists of CPU, ROM71 and RAM72 are provided. The controller 70 makes a predetermined determination based on input signals from the refrigerant temperature sensors 81a to 81c, the refrigerant temperature sensors 82a to 82c, and the air temperature sensors 91a to 91c. Further, based on the determination result, various functional components such as the compressor 10, the blower 21, the electronic expansion valves 30a to 30c, the flow rate adjustment valves 51 to 53, and the internal blower (not shown) are appropriately driven. It is configured.

  The ROM 71 includes an opening degree control table (not shown) used for opening degree control of each of the electronic expansion valves 30a to 30c and the flow rate adjusting valves 51 to 53 in addition to the control program executed by the control unit 70. A frequency control table (not shown) relating to the rotation speed control of the compressor 10 is stored. In the opening degree control table, the valve opening degree of each of the electronic expansion valves 30a to 30c is changed according to the values of the superheat degrees H1a to H1c calculated from the refrigerant temperature sensors 81a to 81c and the refrigerant temperature sensors 82a to 82c. The amount (number of pulses) is specified. Further, the opening degree control table includes values of evaporation temperatures Tea to Tec based on the refrigerant temperature sensors 81a to 81c (more precisely, target evaporation temperatures Tga (Tgb and Tgc) and current evaporation temperatures Tea (Teb and Tec). The amount of change (number of pulses) of the valve opening degree of each of the flow rate adjustment valves 51 to 53 according to the difference) is defined. The RAM 72 temporarily stores control parameters used when the control program is executed. The cooling device 100 in the first embodiment is configured as described above.

  In the first embodiment, the following effects can be obtained.

  In the first embodiment, as described above, the evaporation temperature Tea of the refrigerant in the evaporator 40a is controlled by controlling the opening degree of the flow rate adjustment valve 51 based on the superheat degree H1a of the refrigerant in the evaporator 40a. A configured control unit 70 is provided. Accordingly, the opening degree of the flow rate adjusting valve 51 is controlled while grasping the difference between the cooling capacity of the evaporator 40a being controlled and the actually required cooling capacity based on the superheat degree H1a of the refrigerant in the evaporator 40a. Therefore, the state of the evaporator 40a can be adjusted so as to have an appropriate evaporation pressure (evaporation temperature Tea). As a result, since the evaporation temperature Tea of the evaporator 40a can be made to follow according to the fluctuation | variation of the thermal load which the accommodating area | region A has, the cooling temperature can be controlled stably. The above effect is the same when the evaporator 40b cools the storage area B and when the evaporator 40c cools the storage area C.

  In the first embodiment, a refrigerant temperature sensor 81a that detects the refrigerant temperature T1a in the vicinity of the inlet of the evaporator 40a and a refrigerant temperature sensor 82a that detects the refrigerant temperature T2a in the vicinity of the outlet of the evaporator 40a are provided. Then, based on the refrigerant temperature T1a detected by the refrigerant temperature sensor 81a and the refrigerant temperature T2a detected by the refrigerant temperature sensor 82a, the opening degree of the flow rate adjustment valve 51 based on the superheat degree H1a of the refrigerant in the vicinity of the outlet of the evaporator 40a. By controlling the above, the control unit 70 is configured to control the evaporation temperature Tea. Thereby, the state of the evaporator 40a can be accurately grasped based on the superheat degree H1a of the refrigerant grasped by the refrigerant temperature sensor 81a and the refrigerant temperature sensor 82a. Therefore, it is possible to appropriately follow the evaporation temperature Tea of the evaporator 40a in accordance with the accurately grasped fluctuation of the heat load. The above effect is the same for the evaporator 40b and the evaporator 40c.

  In the first embodiment, the refrigerant temperature T1a detected by the refrigerant temperature sensor 81a and the refrigerant temperature detected by the refrigerant temperature sensor 82a under the evaporation temperature Tea adjusted by the opening degree control of the flow rate adjustment valve 51. Based on T2a, the controller 70 is configured to control the opening degree of the electronic expansion valve 30a so that the superheat degree H1a of the refrigerant in the vicinity of the outlet of the evaporator 40a becomes a predetermined value. Thereby, the superheat degree H1a of the refrigerant in the vicinity of the outlet of the evaporator 40a can be further finely controlled under the evaporation temperature Tea appropriately adjusted according to the fluctuation of the heat load. That is, the degree of refrigerant evaporation can be optimized by adjusting the opening of the electronic expansion valve 30a while grasping the degree of evaporation of the refrigerant in the evaporator 40a whose evaporation temperature Tea has been adjusted. Thereby, the evaporator 40a can be used most effectively and efficiently with respect to the evaporation of the refrigerant. As a result, the heat exchange efficiency of the entire evaporator 40a can be maintained high. The above effect is the same for the evaporator 40b and the evaporator 40c.

  Moreover, in 1st Embodiment, the flow regulating valves 51, 52, and 53 are provided corresponding to each of the evaporators 40a, 40b, and 40c, respectively. Then, the evaporators 40a, 40b are controlled by controlling the opening degree of the flow rate adjusting valves 51, 52, 53 corresponding to the respective refrigerant superheat degrees H1a, H1b, and H1c based on the refrigerant superheat degrees H1a, H1b, and H1c. And the control part 70 is comprised so that the evaporation temperature Tea, Teb, and Tec of the refrigerant | coolant for every 40c may be controlled separately. As a result, the entire cooling device 100 can be operated and controlled so that the evaporation pressures (evaporation temperatures Tea, Teb and Tec) suitable for each of the evaporators 40a, 40b and 40c can be obtained while grasping the cooling capacity required for each of the evaporators 40a, 40b and 40c. it can. Moreover, since the cooling temperature of each of the evaporators 40a, 40b, and 40c can be stably controlled, the cooling device 100 can be efficiently operated.

(Second Embodiment)
The second embodiment will be described with reference to FIGS. 3 and 4. In the second embodiment, unlike the first embodiment, the evaporator 40a (40b and 40c) 40a is added to the refrigerant temperature sensor 82a (82b and 82c) provided in the refrigerant pipe 5a (5b and 5c). (40b and 40c) An example will be described in which the refrigerant temperature sensor 83a (83b and 83c) is also provided in the refrigerant pipe portion inside to control the opening degree of the electronic expansion valve 30a (30b and 30c). Each of the refrigerant temperature sensors 83a to 83c is an example of the “internal refrigerant temperature detector” of the present invention. In the drawing, the same reference numerals as those in the first embodiment are attached to the same components as those in the first embodiment.

  In the cooling device 200 according to the second embodiment of the present invention, as shown in FIGS. 3 and 4, the refrigerant temperature sensor 83a (83b and 83c) is provided in the refrigerant pipe portion inside the evaporator 40a (40b and 40c). Yes. The refrigerant temperature sensors 83a to 83c are connected to the control unit 270 (see FIG. 4). The refrigerant temperature sensor 83a (83b and 83c) has a role of detecting the refrigerant temperature T3a (T3b and T3c) of the refrigerant that individually flows through the evaporator 40a (40b and 40c). The cooling device 200 is installed in a refrigerated warehouse 205 (see FIG. 3).

  Thereby, in 2nd Embodiment, about the evaporator 40a which cools the storage area | region A (low temperature region: around -20 degreeC) of the refrigerator warehouse 205, the refrigerant | coolant temperature T2a detected by the refrigerant | coolant temperature sensor 82a and the refrigerant | coolant temperature sensor 83a. The opening degree of the electronic expansion valve 30a is controlled based on the refrigerant temperature T3a detected by. More specifically, electronic expansion is performed so that the superheat degree H2a of the refrigerant in the vicinity of the outlet of the evaporator 40a based on the refrigerant temperature T3a and the refrigerant temperature T2a (= refrigerant temperature T2a−refrigerant temperature T3a) is maintained at a predetermined value. The opening degree of the valve 30a is finely controlled.

  That is, in the second embodiment, the superheat degree control of the refrigerant at the outlet of the evaporator 40a is performed in consideration of the pressure loss of the refrigerant flowing through the evaporator 40a. In other words, depending on the size of the evaporator 40a (the length of the heat transfer tube that reciprocally meanders), the refrigerant temperature T1a (in the vicinity of the inlet of the evaporator 40a) due to the pressure loss of the refrigerant pipe (a phenomenon in which the evaporation pressure drops) In some cases, the evaporation temperature (saturated vapor temperature) of the refrigerant in the evaporator 40a is lower than the evaporation temperature (saturated vapor temperature). Therefore, in this case, the refrigerant temperature T3a (evaporation temperature Tea) inside the evaporator 40a (intermediate part of the refrigerant pipe from the inlet to the outlet) detected by the refrigerant temperature sensor 83a, not the refrigerant temperature T1a in the vicinity of the inlet. The flow rate control of the refrigerant is performed based on the superheat degree H2a of the refrigerant in the vicinity of the outlet of the evaporator 40a. Thereby, it is comprised so that the superheat degree control of the refrigerant | coolant in the exit part of the evaporator 40a may be performed more accurately.

  The same applies to the evaporator 40b and the evaporator 40c. The evaporator 40b that cools the storage area B is detected by the refrigerant temperature T3b detected by the refrigerant temperature sensor 83b and the refrigerant temperature sensor 82b under the evaporation temperature Teb adjusted by the opening degree control of the flow rate adjustment valve 52. The degree of opening of the electronic expansion valve 30b is finely controlled so that the superheat degree H1b of the refrigerant in the vicinity of the outlet of the evaporator 40b (= refrigerant temperature T2b-refrigerant temperature T3b) becomes a predetermined value based on the refrigerant temperature T2b. The For the evaporator 40c that cools the storage area C, the refrigerant temperature T3c and the refrigerant temperature sensor 82c detected by the refrigerant temperature sensor 83c under the evaporation temperature Tec adjusted by the opening degree control of the flow rate adjustment valve 53. The degree of opening of the electronic expansion valve 30c is finely adjusted so that the superheat degree H1c of the refrigerant in the vicinity of the outlet of the evaporator 40c (= refrigerant temperature T2c−refrigerant temperature T3c) becomes a predetermined value based on the refrigerant temperature T2c detected by Be controlled.

  Also in this case, the cooling device 200 determines the low pressure in the refrigeration cycle by controlling the rotation speed of the compressor 10, while using the flow rate adjustment valve 51 according to the set temperature (heat load) of the storage areas A to C. Thus, the evaporation pressure (evaporation temperature Tea) of the evaporator 40a is independently controlled, and the evaporation pressure (evaporation temperature Teb) of the evaporator 40b is uniquely controlled using the flow rate adjustment valve 52. Furthermore, the evaporation pressure (evaporation temperature Teb) of the evaporator 40c is independently controlled using the flow rate adjusting valve 53. At this time, the flow rate adjustment valves 51 to 53 are based on the evaporation temperature Tea to the evaporation temperature Tec that are accurately detected by the refrigerant temperature sensors 83a to 83c in real time and considering each pressure loss in the evaporators 40a to 40c. Each of the valve openings is freely increased or decreased. Thereby, the cooling capacity of each of the evaporators 40a to 40c is finely adjusted so as to have a desired size. In addition, the other structure of the cooling device 200 by 2nd Embodiment is the same as that of the said 1st Embodiment.

  In the second embodiment, the following effects can be obtained.

  In 2nd Embodiment, the refrigerant | coolant temperature sensor 83a which detects the refrigerant | coolant temperature T3a inside the evaporator 40a is provided. Then, based on the refrigerant temperature T3a detected by the refrigerant temperature sensor 83a and the refrigerant temperature T2a detected by the refrigerant temperature sensor 82a, the opening degree of the flow rate adjustment valve 51 based on the superheat degree H2a of the refrigerant in the vicinity of the outlet of the evaporator 40a. And the refrigerant temperature T3a detected by the refrigerant temperature sensor 83a and the refrigerant temperature T2a detected by the refrigerant temperature sensor 82a under the evaporation temperature Tea adjusted by the opening degree control of the flow rate adjusting valve 51. Based on this, the control unit 270 is configured to control the opening degree of the electronic expansion valve 30a.

  Thereby, the superheat degree control of the refrigerant at the outlet of the evaporator 40a can be performed in consideration of the pressure loss inside the evaporator 40a. That is, depending on the size of the evaporator 40a (the length of the heat transfer tube), it evaporates more than the evaporation temperature (refrigerant temperature T1a) near the inlet of the evaporator 40a due to the pressure loss (evaporation pressure drop) of the refrigerant flow path. There is a case where the refrigerant evaporation temperature (refrigerant temperature T3a) inside the container 40a is low. Therefore, the refrigerant is based on the superheat degree H2a of the refrigerant in the vicinity of the outlet of the evaporator 40a when the refrigerant temperature T3a in the evaporator 40a detected by the refrigerant temperature sensor 83a is used as a reference instead of the refrigerant temperature T1a in the vicinity of the inlet. By performing this flow rate control, the superheat degree control of the refrigerant at the outlet of the evaporator 40a can be performed with higher accuracy. As a result, the evaporation completion point of the refrigerant in the evaporator 40a can be more reliably positioned in the vicinity of the outlet of the evaporator 40a, so that almost all refrigerant flow paths from the inlet to the outlet of the evaporator 40a are used as the evaporation region. Can be used. As a result, the heat exchange performance (cooling capacity) of the evaporator 40a can be maximized. The above effect is the same for the evaporators 40b and 40c. The remaining effects of the second embodiment are similar to those of the aforementioned first embodiment.

(Third embodiment)
The third embodiment will be described with reference to FIGS. 3, 5, and 6. In the third embodiment, unlike the first and second embodiments, an example in which the cooling device 300 is configured by providing the refrigerant pipe 5a that bypasses the flow rate adjustment valve 51 in the refrigerant pipe 5a corresponding to the evaporator 40a. explain. The refrigerant pipe 5d is an example of the “bypass channel” in the present invention. In the figure, the same reference numerals as those in the first and second embodiments are attached to the same configurations as those in the first and second embodiments.

  The cooling device 300 according to the third embodiment of the present invention is installed in a refrigerated warehouse 305 (see FIG. 5). As shown in FIGS. 5 and 6, in the cooling device 300, the refrigerant pipe 5a provided with the flow rate adjusting valve 51 bypasses the flow rate adjusting valve 51 and the outlet portion of the evaporator 40a, the suction pipe 3, and the like. A refrigerant pipe 5d that directly connects the two is provided. In addition, an electromagnetic valve 54 and an electromagnetic valve 55 are provided for selectively switching the flow of the refrigerant through the flow rate adjustment valve 51 and the flow of the refrigerant not through the flow rate adjustment valve 51, respectively. The electromagnetic valves 54 and 55 are electrically connected to the control unit 370 (see FIG. 6).

  Here, when the electromagnetic valve 54 is open, the electromagnetic valve 55 is closed and the refrigerant flowing out of the evaporator 40 a is circulated only to the flow rate adjustment valve 51. On the contrary, when the solenoid valve 54 is closed, the solenoid valve 55 is opened, and the refrigerant flowing out of the evaporator 40 a completely bypasses the flow rate adjusting valve 51 and flows to the suction pipe 3.

  Thereby, in 3rd Embodiment, when the solenoid valve 54 is an open state and the solenoid valve 55 is a closed state, based on the instruction | command of the control part 370 (refer FIG. 6), the cooling device 200 in the said 2nd Embodiment. Operation control similar to that shown in FIG. 3 is performed. That is, according to the set temperature (heat load) of the storage areas A to C, the evaporation temperature Tea of the evaporator 40a using the flow rate adjustment valve 51 based on the degree of superheat H2a and the flow rate adjustment valve 52 based on the degree of superheat H2b were used. The evaporation temperature Teb of the evaporator 40b and the evaporation temperature Tec of the evaporator 40c using the flow rate adjustment valve 53 based on the superheat degree H2c are independently controlled.

  On the other hand, when the solenoid valve 54 is closed and the solenoid valve 55 is open, the cooling capacity of the evaporator 40a is controlled based on the superheat degree control only by the electronic expansion valve 30a without using the flow rate adjustment valve 51. It is comprised so that.

  That is, in 3rd Embodiment, when the evaporation temperature Tea of the refrigerant | coolant of the evaporator 40a in which the refrigerant | coolant piping 5d (bypass flow path) was provided is the lowest among the evaporators 40a-40c, the flow volume parallel to the refrigerant | coolant piping 5d. Control is performed to circulate the refrigerant through the refrigerant pipe 5d without causing the refrigerant to flow through the regulating valve 51. In this state, the evaporation temperature Teb of the evaporator 40b using the flow rate adjustment valve 52 based on the degree of superheat H2b, and the evaporation temperature Tec of the evaporator 40c using the flow rate adjustment valve 53 based on the degree of superheat H2c, respectively. Be controlled. In addition, in the control part 370 (refer FIG. 6), the magnitude relationship of target evaporation temperature Tga-Tgc grasped | ascertained based on the setting temperature of accommodation area | region AC is compared. When Tga <Tgb and Tga <Tgc, it is determined that the evaporation temperature Tea of the evaporator 40a needs to be maintained at the lowest level. In this case, the solenoid valve 54 is closed and the solenoid valve 55 is switched to the open state.

  When the target evaporation temperature Tga of the evaporator 40a is the lowest, the control unit 370 adjusts the rotation speed of the compressor 10 so as to obtain an evaporation pressure (low pressure) corresponding to the target evaporation temperature Tga. Thereby, the evaporation pressure (evaporation temperature Tea) of the evaporator 40a is directly determined by the rotation speed of the compressor 10. On the other hand, with respect to the evaporator 40b (40c), the opening degree of the flow rate adjustment valve 52 (53) is increased or decreased while referring to the degree of superheat H1b (H1c), and the evaporation temperature Teb (Tec) becomes the target evaporation temperature Tgb (Tgc). ).

  As described above, in the cooling device 300, the flow rate adjusting valve 51 is used to largely adjust the evaporation temperature Tea of the evaporator 40a, and the cooling device 300 is determined by the rotation speed of the compressor 10 without significantly adjusting the evaporation temperature Tea. The case where the low pressure (intake pressure) is used as it is and the evaporator 40a exhibits a large cooling capacity can be switched. Even when the flow rate adjustment valve 51 is fully opened without providing the refrigerant pipe 5d, an unnecessary restriction (circulation resistance) that remains in the flow rate adjustment valve 51 is generated. By providing the refrigerant pipe 5d and bypassing the flow rate adjustment valve 51, unnecessary pressure loss is avoided on the downstream side of the evaporator 40a. Further, since unnecessary pressure loss does not occur in the refrigerant pipe 5d, the compression ratio (the ratio between the high pressure and the low pressure) of the compressor 10 is prevented from increasing unnecessarily. In addition, the other structure of the cooling device 300 by 3rd Embodiment is the same as that of the said 1st Embodiment.

  In the third embodiment, the following effects can be obtained.

  In the third embodiment, the refrigerant pipe 5d is provided in parallel with the flow rate adjustment valve 51 and bypasses the flow rate adjustment valve 51 and connects the outlet side of the evaporator 40a and the suction pipe 3 (the suction side of the compressor 10). Is provided. And when the evaporation temperature Tea of the refrigerant | coolant of the evaporator 40a corresponding to the refrigerant | coolant flow path in which the refrigerant | coolant piping 5d was provided among the evaporators 40a-40c is the lowest, it is refrigerant | coolant to the flow regulating valve 51 parallel to the refrigerant | coolant piping 5d. The refrigerant 40b and 40c other than the evaporator 40a having the lowest refrigerant evaporation temperature Tea in a state where the refrigerant is circulated through the refrigerant pipe 5d without circulating the refrigerant, based on the corresponding superheat degrees H2b and H2c of the refrigerant. Thus, the control unit 370 is configured to individually control the evaporation temperatures Tea to Tec of the refrigerant in the evaporators 40a to 40c by controlling the opening degrees of the flow rate adjusting valves 52 and 53, respectively.

  Thereby, when the evaporation temperature Tea of the specific evaporator 40a is the lowest among the evaporators 40a to 40c, an unnecessary throttle (circulation resistance) by the flow rate adjusting valve 51 causes the refrigerant pipe 5d on the downstream side of the evaporator 40a. Can be avoided. Therefore, even when operating the cooling device 300 in which the evaporators 40a to 40c having different cooling capacities are operated, a load is applied to the compressor 10 due to unnecessary restriction (circulation resistance) (the compression ratio increases). Can be suppressed. The remaining effects of the third embodiment are similar to those of the aforementioned first embodiment.

(Fourth embodiment)
The fourth embodiment will be described with reference to FIGS. 1, 5, 7 and 8. In the fourth embodiment, unlike the first embodiment, an example in which the cooling device 400 is configured such that the flow rate adjustment valve 51 (see FIG. 1) is not provided in the refrigerant pipe 5a corresponding to the evaporator 40a will be described. To do. In the drawing, the same reference numerals as those in the first embodiment are attached to the same components as those in the first embodiment.

  The cooling device 400 according to the fourth embodiment of the present invention is installed in a refrigerated warehouse 405 (see FIG. 7). As shown in FIGS. 7 and 8, in the cooling device 400, the flow rate adjustment valve 52 is provided in the refrigerant pipe 5b corresponding to the evaporator 40b that cools the storage area B to the middle temperature range, and the storage area C is set in the high temperature range. A flow rate adjustment valve 53 is provided in the refrigerant pipe 5c corresponding to the evaporator 40c that cools the air. On the other hand, the flow rate adjustment valve 51 (see FIG. 1) is not provided in the refrigerant pipe 5a on the downstream side of the evaporator 40a that cools the containing area A to the low temperature area.

  Thereby, the evaporator 40a always exhibits the greatest cooling capability among the evaporators 40a to 40c by using the low pressure (intake pressure) determined by the rotation speed of the compressor 10 as it is. This state corresponds to a circuit configuration when the electromagnetic valve 54 is switched to the closed state and the electromagnetic valve 55 is switched to the opened state in the cooling device 300 (see FIG. 5) in the third embodiment. In addition, the other structure of the cooling device 400 by 4th Embodiment is the same as that of the said 1st Embodiment.

  In the fourth embodiment, the following effects can be obtained.

  In 4th Embodiment, the flow volume adjustment valve 51 is not provided in the downstream of the evaporator 40a which requires the cooling capacity most among the evaporators 40a-40c. Thus, unlike the case where the refrigerant pipe 5d that bypasses the flow rate adjustment valve 51 and the electromagnetic valves 54 and 55 that switch the flow path are provided as in the third embodiment, the configuration of the refrigerant circuit is simplified. The evaporator 40a can exhibit a large cooling capacity. Thus, when it is known that the evaporator 40a requires the most cooling capacity, evaporation obtained directly from the rotation speed control of the compressor 10 while simplifying the configuration of the cooling device 400. The evaporator 40a can be made to function using the pressure (evaporation temperature Tea). The remaining effects of the fourth embodiment are similar to those of the aforementioned third embodiment.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, in the first to fourth embodiments, the example in which the three evaporators 40a to 40c are connected in parallel to each other on the low-pressure side with respect to one refrigerant circuit is shown, but the present invention is not limited to this. . In other words, the “flow rate adjusting valve” of the present invention may be provided for a cooling device consisting of only one evaporator to control the evaporation temperature, or a cooling device in which four or more evaporators are connected in parallel. On the other hand, the flow rate adjusting valve of the present invention may be provided to individually control the evaporation temperature (evaporation pressure) of each evaporator.

  Moreover, in the said 3rd Embodiment, although the example which provided the refrigerant | coolant piping 5d which bypasses the flow volume adjusting valve 51 only in the refrigerant | coolant piping 5a corresponding to the evaporator 40a was shown, this invention is not limited to this. The “bypass channel” of the present invention may be provided not only in the refrigerant pipe 5a corresponding to the evaporator 40a but also in the refrigerant pipe 5b corresponding to the evaporator 40b and the refrigerant pipe 5c corresponding to the evaporator 40c. By providing a bypass flow path that bypasses the flow rate adjustment valve 52 and a bypass flow path that bypasses the flow rate adjustment valve 53, any of the evaporators 40a to 40c provided with the bypass flow path has a refrigerant flow rate. When the evaporation temperature is the lowest, the corresponding bypass flow paths can be opened. That is, it is possible to adjust the cooling capacity by simply controlling the degree of superheat without circulating the refrigerant through the flow rate adjusting valve in the circuit in which the bypass flow path is opened.

  Moreover, although the said 4th Embodiment showed about the example which comprised the cooling device 400 so that the flow regulating valve 51 might not be provided downstream of the evaporator 40a among the evaporators 40a-40c, this invention is limited to this. Absent. That is, the cooling device 400 may be configured such that the flow rate adjusting valve 53 is provided only downstream of the evaporator 40c without providing the flow rate adjusting valves 51 and 52 downstream of the evaporators 40a and 40b.

  Moreover, although the said 1st-4th embodiment showed about the example using the inverter control type compressor which can control refrigerant | coolant discharge amount by the rotation speed change to the compressor 10, this invention is not limited to this. . For example, the cooling devices 100 to 400 may be configured using a constant speed (non-variable capacity) compressor 10 that does not use inverter control. Further, as the compressor 10, any of a reciprocating compressor, a rotary compressor, a scroll compressor, a screw compressor, and the like may be used regardless of the control method (inverter control type or constant speed type). .

  Moreover, although the said 1st-4th embodiment showed about the example which comprised the cooling devices 100-400 using the one compressor 10, this invention is not limited to this. That is, a plurality of compressors may be connected in parallel (tandem arrangement) to one refrigeration cycle (refrigerant circuit constituting the cooling device).

  In the first to fourth embodiments, the so-called refrigerator built-in type (integrated type) cooling device 100 to 400 in which the refrigerator unit (condensing unit) including the compressor 10 and the gas cooler 20 is built is refrigerated. Although the example installed in the warehouses 105 to 405 is shown, the present invention is not limited to this. For example, only the cooling unit (indoor unit) including the electronic expansion valves 30a to 30c, the evaporators 40a to 40c, and the flow rate adjusting valves 51 to 53 is provided on the side of the refrigerator warehouse 105 to 405, and includes the compressor 10 and the gas cooler 20 and the like. A refrigerator (outdoor unit) may be arranged outdoors. Then, the present invention is applied to a separate type (separation type) cooling device configured by connecting a cooling unit and a refrigerator with refrigerant pipes (liquid pipe 2 and suction pipe (gas pipe) 3). Also good.

  Moreover, although the said 1st-4th embodiment showed about the example which applied the "cooling apparatus" of this invention to the refrigeration warehouses 105-405, this invention is not limited to this. For example, for other than refrigerated warehouses, such as showcases, commercial refrigerators, household refrigerators, air conditioners (especially air conditioning systems for facilities such as computer rooms where cooling operation (cooling operation) is required throughout the year), etc. A “cooling device” may be applied. In addition, the present invention may be applied to a refrigerator car having a freezer compartment divided into different cooling temperature zones. Further, the “cooling device” of the present invention includes a heat pump device capable of switching between a cooling operation and a heating operation, and can be applied during the cooling operation in this case.

  Moreover, in the said 1st-4th embodiment, although this invention was applied with respect to the cooling device with which the fin and tube type air heat exchanger was used for the evaporator, it is not this limitation. That is, the present invention is applied to a cooling device including an evaporator capable of exchanging heat with another heat exchange fluid (water, brine, etc.) via a pressure vessel in which the refrigerant can evaporate at a predetermined evaporation temperature. May be.

  Moreover, in the said 1st-4th embodiment, the accommodating area | region A is maintained in a low temperature range by the evaporator 40a as an example, the accommodating area | region B is maintained in an intermediate temperature range by the evaporator 40b, and the accommodating area | region C is maintained by the evaporator 40c. Although the example which comprised the cooling devices 100-400 so that it might maintain in a high temperature range was shown, this invention is not limited to this. That is, the individual correspondence relationship between the storage areas A to C and the low temperature range to the high temperature range may be other than the above.

In the above-mentioned first to fourth embodiments, carbon dioxide (CO ₂₎ is shown an example of operating the cooling device 100 to 400 by using a refrigerant, the present invention is not limited thereto. A natural refrigerant other than the carbon dioxide refrigerant may be used, or an alternative chlorofluorocarbon refrigerant having an ozone layer depletion coefficient of zero may be used.

4a, 4b, 4c Refrigerant piping 5a, 5b, 5c Refrigerant piping 5d Refrigerant piping (bypass flow path)
10 Compressor 20 Gas cooler (condenser)
30a, 30b, 30c Electronic expansion valve (expansion valve)
40a, 40b, 40c Evaporator 51, 52, 53 Flow rate adjusting valve 54, 55 Solenoid valve 70, 270, 370 Controller 81a, 81b, 81c Refrigerant temperature sensor (first refrigerant temperature detector)
82a, 82b, 82c Refrigerant temperature sensor (second refrigerant temperature detector)
83a, 83b, 83c Refrigerant temperature sensor (first refrigerant temperature detector, internal refrigerant temperature detector)
91a, 91b, 91c Air temperature sensor 100, 200, 300, 400 Cooling device 105, 205, 305, 405 Refrigerated warehouse

Claims (4)

A compressor for compressing the refrigerant;
A condenser that condenses the refrigerant;
An electronic expansion valve for expanding the refrigerant condensed by the condenser;
An evaporator for evaporating the refrigerant expanded by the electronic expansion valve;
A flow rate adjusting valve for adjusting the flow rate of the refrigerant flowing out of the evaporator according to the opening;
A first refrigerant temperature detector that detects at least one of a refrigerant temperature near the inlet of the evaporator or a refrigerant temperature inside the evaporator;
A second refrigerant temperature detector for detecting a refrigerant temperature in the vicinity of the outlet of the evaporator;
The flow rate adjustment valve is opened based on the degree of superheat of the refrigerant in the vicinity of the outlet of the evaporator based on the refrigerant temperature detected by the first refrigerant temperature detector and the refrigerant temperature detected by the second refrigerant temperature detector. A control unit configured to control the evaporation temperature of the refrigerant in the evaporator by controlling the degree ,
The control unit is detected by the refrigerant temperature detected by the first refrigerant temperature detection unit and the second refrigerant temperature detection unit based on the evaporation temperature adjusted by opening control of the flow rate adjustment valve. superheat of the refrigerant at the outlet vicinity of the evaporator based on the refrigerant temperature has been configured to control an opening degree of the electronic expansion valve to a predetermined value, the cooling device. The first refrigerant temperature detection unit includes an internal refrigerant temperature detection unit that detects a refrigerant temperature inside the evaporator,
The control unit is configured to control the flow rate based on the degree of superheat of the refrigerant in the vicinity of the outlet of the evaporator based on the refrigerant temperature detected by the internal refrigerant temperature detection unit and the refrigerant temperature detected by the second refrigerant temperature detection unit. While controlling the opening degree of the regulating valve, the refrigerant temperature detected by the internal refrigerant temperature detecting unit and the second refrigerant temperature detecting unit based on the evaporation temperature adjusted by the opening degree control of the flow rate adjusting valve The cooling device according to claim 1 , wherein the cooling device is configured to control an opening degree of the electronic expansion valve based on the refrigerant temperature detected by the step. Each of the plurality of evaporators is connected in parallel with each other, and the electronic expansion valve is provided upstream of each of the evaporators,
The flow rate adjusting valve is provided corresponding to each of the plurality of evaporators,
The control unit individually controls the evaporation temperature of the refrigerant for each evaporator by controlling the opening degree of the flow rate adjustment valve corresponding to each of the evaporators based on the degree of superheat of the refrigerant for each evaporator. is configured, the cooling device according to claim 1 or 2. Provided in parallel with the flow rate adjustment valve, further comprising a bypass flow path that bypasses the flow rate adjustment valve and connects the outlet side of the evaporator and the suction side of the compressor;
The control unit adjusts the flow rate in parallel with the bypass flow path when the evaporation temperature of the refrigerant of the evaporator corresponding to the refrigerant flow path provided with the bypass flow path is the lowest among the plurality of evaporators. The flow rate adjustment based on the degree of superheat of the corresponding refrigerant with respect to an evaporator other than the evaporator having the lowest refrigerant evaporation temperature in a state where the refrigerant is circulated through the bypass channel without circulating the refrigerant through the valve The cooling device according to claim 3 , wherein the cooling device is configured to individually control the evaporation temperature of the refrigerant for each of the evaporators by controlling the opening of the valve.

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