JP2013083396A - Temperature control device, and temperature maintaining facility - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a temperature control device which: is optimal for a refrigerating chamber and a freezing chamber constructed by combining elements of a commercially available compressor etc.; satisfies specifications of a customer; and can reduce electric power consumption.SOLUTION: The temperature control device 1 includes: a refrigerant circulation passage 2 in which a refrigerant sent out from a compressor 8 is circulated; a control valve 3 controlling the amount of the refrigerant circulating in the refrigerant circulation passage 2; a temperature detector 4 measuring a temperature of a temperature maintenance chamber 7 maintained at a level near a target temperature by heat exchange of the refrigerant; and a control portion 5 controlling the control valve 3. The control portion 5 controls the control valve 3 in accordance with a PID (proportional integral derivative) control method for a change period from a first temperature which is higher than the target temperature by a predetermined temperature to a second temperature which is lower than the target temperature by a predetermined temperature (hereinafter referred to as "first period"), and reduces opening of the control valve 3 for a change period from the second temperature to the first temperature (hereinafter referred to as "second period").

Description

  The present invention relates to a temperature control device that is suitably used for equipment that needs to maintain a temperature within a certain range, such as a refrigerator room, a freezer room, and a temperature-controlled room, and a temperature maintenance equipment that uses the temperature control apparatus.

  Equipment such as refrigerator rooms, freezer rooms and temperature-controlled rooms are used in various ways in food factories, precision instrument factories, chemical improvement, research laboratories and other offices. In these establishments, it is necessary to store raw materials, parts, products, etc. under certain temperature conditions, and to perform production and experiments using them. For this reason, facilities, such as a refrigerator compartment, a freezer compartment, and a temperature-controlled room, maintain the inside at predetermined temperature using the compressor which circulates a refrigerant | coolant. In particular, a technique for maintaining (that is, cooling) a temperature lower than a general room temperature or an outside air temperature (that is, cooling) is a very delicate technique and requires various elemental techniques and a combination thereof.

  Here, there are provided devices such as a so-called refrigerator, freezer, and thermostatic chamber integrated with a compressor, a compressor control device, a refrigerant circulation path, and a heat exchanger that performs indoor temperature exchange in the refrigerant circulation. These devices are manufactured and sold with all necessary elements, and the purchaser need only install them as they are. Such a device that only needs to be installed in an integrated type is not so high in accuracy required for temperature control as long as it can maintain a temperature within a certain range. For this reason, the integrated device is used for small-scale and low-precision refrigeration and freezing.

  On the other hand, there are a refrigerator room, a freezer room, and a temperature-controlled room as facilities to be designed and constructed according to customer requirements. For example, in a business establishment, there are specifications and conditions such as a predetermined area, a predetermined volume, an object, and a temperature to be maintained, and it is designed by combining units and elements necessary for constructing a refrigerator compartment or a freezer compartment. There are refrigerator rooms, freezer rooms, and temperature-controlled rooms. Demand for such facilities as refrigerated rooms and freezer rooms is increasing with the diversification and sophistication of business establishments.

  In particular, as the precision of raw materials and parts stored and used in business establishments has improved, the level of demand for refrigerated rooms and freezer rooms to be constructed is increasing year by year. For this reason, the request | requirement with respect to the temperature conditions with respect to the refrigerator compartment and freezer compartment to be constructed is also increasing. For example, the required temperature for the set temperature and the temperature range is becoming severe as the set temperature in the refrigerator compartment is 5 ° C. and the temperature range is 1 ° C. up and down.

  Here, refrigeration rooms and freezer rooms that are constructed according to customer requirements are based on commercially available compressors, and contractors design refrigerant circulation paths, refrigerator rooms, heat exchangers, control devices, etc. Then, the final refrigerator compartment and freezer compartment are installed in combination with the compressor. In other words, the contractor satisfies the customer's request by improving and improving the refrigerant circulation path, the refrigerator compartment, the heat exchanger, the control device, and the like. The demand for temperature conditions is also realized by special design and construction of these elements and units.

  In order to satisfy the temperature condition, in the refrigerator compartment or freezer compartment as such equipment, the operation of the compressor is controlled, and various techniques have been proposed (for example, Patent Document 1, 2).

JP 2009-174730 A JP 2011-64412 A

  In the prior art, in order to satisfy the temperature condition, there is a technique for detecting the temperature in the refrigerator compartment or the freezer compartment and stopping the operation of the compressor when a predetermined first temperature lower than the set temperature is reached. Conversely, when the predetermined second temperature higher than the set temperature is reached, the operation of the compressor is resumed. As described above, there is a technique for controlling the temperature of a refrigerator compartment or a freezer compartment that is a temperature control target by operating and stopping the compressor (ON control and OFF control).

  Such a temperature control technology for switching between operation and stop of the compressor is a simple technology and has an advantage of low manufacturing cost and design cost. However, every time the compressor is stopped and restarted, Operating energy is required and power consumption increases. This is because a large amount of starting energy is required to change from the stopped state to the operating state. Further, the temperature control technique for switching between operation and stop shortens the time required for the change between the first temperature and the second temperature, and repeats operation and stop in a fine cycle. As a result, there is a problem that the operation period of the compressor per unit time becomes long and the power consumption becomes high.

  Patent Document 1 discloses a technique for controlling the rotational speed of a compressor in a refrigeration apparatus using a compressor. In particular, a technique is disclosed in which, when the compressor is in operation, rotation of the compressor is stopped using proportional integral differential control (hereinafter referred to as “PID control”) when the temperature becomes a predetermined temperature or lower.

  However, since Patent Document 1 controls the rotational speed of the compressor (including stopping the rotational speed), the burden on the compressor increases. When the burden increases, the power consumption of the compressor and the freezer apparatus as a whole increases. In addition, since the rotation of the compressor is frequently stopped and restarted, there is a problem that the noise becomes severe.

  On the other hand, the freezer which patent document 1 makes object is a freezer as an apparatus with which a compressor, a heat exchanger, etc. are manufactured integrally. For this reason, since the compressor and the freezer itself are small and integrated, it is assumed that there is little influence on the power consumption of the compressor even if the rotation speed of the compressor is stopped and restarted according to the temperature in the freezer. A technique for controlling the rotational speed of a compressor using PID control has been proposed.

  However, in refrigeration rooms and freezer rooms as equipment installed in factories and business establishments, temperature control technology that directly controls the rotation speed of the compressor frequently causes the operation and stoppage of the compressor, resulting in power consumption and Noise problems will occur. Moreover, in the refrigerator compartment and freezer compartment as equipment, a commercially available compressor is often used. A commercially available compressor sends out a liquid refrigerant, and receives a reflux of the gas refrigerant. At this time, when the pressure of the refrigerant in the refluxing gas becomes low, the compressor stops its rotation.

  Controlling the rotation of the compressor based on temperature as in Patent Document 1 (also Patent Document 2 described later) suddenly stops the compressor, increasing the burden on the compressor. Of course, the fact that the rotation of the compressor is stopped means that the rotation of the compressor must be restarted, which also increases the burden on the compressor. When restarting, the compressor must circulate refrigerant in a liquid state with a high pressure and a gas state with a low pressure, so that the operation burden when restarting the compressor increases. Naturally, power consumption also increases. A heavy burden on the compressor leads to deterioration of the compressor, and causes a problem of increasing costs.

  Similarly to Patent Document 1, Patent Document 2 discloses a technique for controlling the rotation of the compressor using PID control. Patent Document 2 discloses a technique for simultaneously controlling a fan in addition to rotation of a compressor.

  However, Patent Document 2 discloses controlling the rotational speed of the compressor and the fan using PID control, but does not disclose details of an actual cycle and control. For this reason, when actually setting the set temperature as a target, it is unclear what control method is used to control the compressor and the like. Moreover, when stopping the rotation speed of a compressor, there exists a problem similar to patent document 1. FIG.

  As described above, in the prior art, (1) the power consumption increases in the control technology of repeated operation and stop, and (2) the power consumption and noise problems occur in the technology for controlling the rotation speed of the compressor. (3) When the compressor is stopped and restarted at the temperature, there is a problem that a burden on the compressor becomes large. In particular, in the case of a refrigerator compartment or a freezer compartment as a facility for constructing a refrigerator compartment or a freezer compartment using a commercially available compressor, the problem of (1) to (3) arises because the compressor is large. growing.

  In addition, it is fundamentally difficult to control the rotation of the compressor. This is because commercially available compressors are often pre-installed with a structure that operates and stops according to the pressure of the refluxing gaseous refrigerant. In order to construct a refrigeration facility or a refrigeration facility using a commercially available compressor, it is difficult to modify the compressor so as to control the rotation of the compressor. This is because the quality of the commercially available compressors including the control mechanism is guaranteed, and remodeling the compressors may cause quality problems. Patent document 1 etc. can control rotation of a compressor because it is intended to manufacture a freezer including the compressor itself.

  In other words, with regard to refrigeration rooms and freezer rooms as equipment to be designed and constructed according to customer specifications using various elements and units including commercially available compressors, conventional temperature control can reduce power consumption. There was a problem that it was insufficient in terms of ease of control.

  In addition, refrigeration rooms and freezer rooms with reduced power consumption are required to protect the environment and save power. However, conventional refrigeration rooms and freezer rooms have a problem that power consumption is not sufficiently reduced. It was. Thus, there has been a demand for a control device that is optimal for setting the target temperature and can reduce power consumption without modifying the operation of the compressor itself.

  In view of the above-described problems, the present invention provides a temperature control device that is optimal for a refrigerator room or a freezer room that satisfies the specifications of a customer who puts together components such as a commercially available compressor and can reduce power consumption. For the purpose.

  In view of the above-described problems, the temperature control device of the present invention provides a target with a refrigerant circulation path for circulating the refrigerant sent from the compressor, a control valve for adjusting the amount of refrigerant circulating in the refrigerant circulation path, and heat exchange of the refrigerant. A temperature detection unit that measures the temperature of the temperature maintenance chamber that is maintained near the temperature, and a control unit that controls the control valve. The control unit has a first temperature that is higher than the target temperature by a predetermined temperature and a predetermined temperature that is higher than the target temperature. In the change period from the low temperature to the second temperature (hereinafter referred to as “first period”), the control valve is controlled based on the PID control method, and the change period from the second temperature to the first temperature (hereinafter, referred to as “first period”). In the “second period”), the opening of the control valve is reduced.

  Since the temperature control device of the present invention controls the amount of refrigerant delivered from the compressor in the refrigerant circuit, there is no need to control the commercially available compressor itself. For this reason, temperature control can be performed without improving the compressor itself. In addition, since the temperature is controlled by controlling the amount of refrigerant, the burden on the compressor is reduced.

  In addition, by controlling the amount of refrigerant to a predetermined temperature by PID control and stopping the refrigerant at a predetermined temperature, PID control and stop control are repeated, so that the temperature change of the refrigerator compartment and freezer compartment on the time axis is gentle. become. For this reason, the cycle of temperature change in a predetermined time becomes gentle, and reduction of power consumption is realized. This is because the power consumption time due to the rotation of the compressor at a high frequency and the time for consuming the power for activation are reduced within a predetermined time. Moreover, by using PID control, power consumption can be reduced by eliminating the need to overcool the refrigerator compartment or the freezer compartment.

  As a result, the temperature control device of the present invention can realize environmental protection and power saving.

It is a block diagram which shows the temperature control apparatus in Embodiment 1 of this invention, and its periphery. It is a temperature curve which shows an example of the temperature controlled by the temperature control apparatus in Embodiment 1 of this invention. It is a front view of the heat exchanger 6 in Embodiment 1 of this invention. It is a graph which shows the opening and closing of the control valve in Embodiment 1 of this invention. It is a graph explaining control of the control valve in Embodiment 1 of this invention. It is a schematic diagram of the refrigeration equipment in Embodiment 2 of the present invention. It is a block diagram of the temperature control apparatus which has the temperature control apparatus in Embodiment 3 of this invention, and its periphery. It is a block diagram of the temperature maintenance installation in Embodiment 4 of this invention. It is a schematic diagram of the temperature maintenance installation in Embodiment 5 of this invention.

  A temperature control device according to a first aspect of the present invention includes a refrigerant circulation path that circulates refrigerant sent from a compressor, a control valve that adjusts the amount of refrigerant circulating in the refrigerant circulation path, and heat exchange of the refrigerant. A temperature detection unit that measures the temperature of the temperature maintenance chamber that is maintained near the target temperature; and a control unit that controls the control valve, the control unit starting from a first temperature that is a predetermined temperature higher than the target temperature, from the target temperature In the change period from the second temperature to the second temperature (hereinafter referred to as “first period”), the control valve is controlled based on the PID control method, and the change period from the second temperature to the first temperature (hereinafter referred to as “first period”). , “Second period”), the opening of the control valve is reduced.

  With this configuration, the temperature control device can moderate the temperature change near the target temperature while maintaining the temperature in the temperature maintenance chamber near the target temperature.

  In the temperature control device according to the second aspect of the present invention, in addition to the first aspect, in the first period, the control unit controls the amount of refrigerant passing through the control valve in unit time so as to control the amount of refrigerant. Controls the opening and closing of.

  With this configuration, the temperature control device can maintain the temperature while reducing the burden on the compressor.

  In the temperature control device according to the third aspect of the present invention, in addition to the second aspect, in the first period, the control unit controls the amount of refrigerant passing through the control valve by opening and closing the control valve.

  With this configuration, the temperature control device can maintain the temperature while reducing the burden on the compressor. In addition, the temperature control device can moderate temperature changes and reduce power consumption.

  In the temperature control device according to the fourth aspect of the present invention, in addition to the second aspect, in the first period, the control unit controls the amount of refrigerant passing through the control valve by increasing or decreasing the opening area of the control valve. To do.

  With this configuration, the control unit can adjust the amount of refrigerant passing therethrough in an analog manner.

  In the temperature control device according to the fifth aspect of the present invention, in addition to the third or fourth aspect, the control unit opens and closes the control valve in the first period based on the PID control method.

  With this configuration, the control unit can realize a temperature change in the first period by a gradual temperature change.

  In the temperature control device according to the sixth aspect of the present invention, in addition to any one of the first to fifth aspects, in the second period, the control unit closes the control valve.

  With this configuration, the control unit can realize a temperature change in the second period.

  In the temperature control device according to the seventh aspect of the present invention, in addition to any one of the first to sixth aspects, the compressor is configured such that when the pressure of the refrigerant returning through the refrigerant circulation path is equal to or lower than a predetermined value, Stop its rotation.

  With this configuration, the operation of the compressor is linked to the refrigerant pressure control by the control unit.

  In the temperature control device according to the eighth aspect of the present invention, in addition to any of the first to seventh aspects, the temperature detection unit is located at the rear end of the air circulation in the temperature maintenance chamber.

  The temperature control apparatus according to a ninth aspect of the present invention, in addition to any one of the first to eighth aspects, further includes a heat exchanger provided in the temperature maintenance chamber in the middle of the refrigerant circulation path, The part is located on the intake side of the heat exchanger.

  With these configurations, the temperature detection unit can detect the temperature of the temperature maintenance chamber more accurately.

  In the temperature control device according to the tenth aspect of the present invention, in addition to any of the first to ninth aspects, the difference value between the target temperature and the first temperature is the difference value between the target temperature and the second temperature. Bigger than.

  With this configuration, the control unit can prevent the temperature from being excessively lowered in the first period.

  In the temperature control device according to the eleventh aspect of the present invention, in addition to any of the first to tenth aspects, the temperature maintenance room is at least one of a refrigerator room, a freezer room, and a temperature-controlled room.

  With this configuration, the temperature control device is applied to various uses that require temperature control.

  In the temperature control device according to the twelfth aspect of the present invention, in addition to any one of the first to eleventh aspects, a buffer tank is provided in the refrigerant circulation path at a position where the refrigerant returns to the thermal compressor.

  With this configuration, the pressure of the refrigerant returning to the compressor is maintained, and the frequency of stopping the compressor can be reduced. As a result, power consumption can be reduced.

  In the temperature control device according to the thirteenth aspect of the present invention, in addition to the twelfth aspect, the buffer tank temporarily stores a predetermined amount of vaporized refrigerant that recirculates the refrigerant circulation path to the compressor.

  With this configuration, the buffer tank can maintain a constant pressure for a predetermined time.

  In the temperature control device according to the fourteenth invention of the present invention, in addition to the twelfth or thirteenth invention, the refrigerant reflux path sends vaporized refrigerant to the bottom surface of the buffer tank, and the buffer tank contains vaporized refrigerant to be stored, It sends out to the compressor from the bottom of the buffer tank.

  With this configuration, the pressure in the buffer tank can be reliably maintained.

  The temperature control apparatus according to the fifteenth aspect of the present invention further includes a second control unit for controlling the humidity and the atmospheric pressure in the temperature maintenance chamber in addition to any of the first to fourteenth aspects.

  With this configuration, the temperature control device can expand the environmental maintenance of the temperature maintenance chamber.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  (Embodiment 1)

  Embodiment 1 will be described.

(Overview)
First, an overall outline of the temperature control apparatus according to Embodiment 1 of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a block diagram showing a temperature control device and its surroundings in Embodiment 1 of the present invention. The temperature control device 1 includes only elements necessary for the temperature control device in the elements shown in FIG. 1, but is shown together with the whole including the periphery of the temperature control device 1 for convenience of illustration. . FIG. 2 is a temperature curve showing an example of the temperature controlled by the temperature control device in Embodiment 1 of the present invention.

  The temperature control device 1 is mainly used for temperature control of a temperature maintenance chamber that is maintained near a target temperature. Of course, since it is mainly, the temperature control apparatus 1 may be used for various applications such as facilities and equipment to be controlled to a predetermined temperature.

  The temperature control device 1 includes a refrigerant circulation path 2, a control valve 3, a temperature detection unit 4, and a control unit 5. The refrigerant circulation path 2 circulates the refrigerant sent from the compressor 8. The refrigerant circulates in the refrigerant circulation path 2 and plays a role of heat exchange in the heat exchanger 6 provided in the temperature maintenance chamber 7. That is, the refrigerant circulation path 2 circulates a low-temperature refrigerant (in a liquid state) delivered from the compressor 8 to the heat exchanger 6, and returns the refrigerant evaporated by temperature exchange in the heat exchanger 6 to the compressor 8.

  The adjustment valve 3 adjusts the amount of refrigerant passing through the refrigerant circuit 2. The control valve 3 is provided outside the refrigerant circuit 2 and the refrigerant circuit 2 and adjusts the amount of refrigerant circulating in the refrigerant circuit 2. The heat exchange capability in the heat exchanger 6 varies depending on the adjustment of the refrigerant amount.

  The temperature detection unit 4 measures the temperature of the temperature maintenance chamber 7 at which the temperature is maintained near a predetermined target temperature by the temperature control device 1. That is, the temperature detection unit 4 can check the control by the temperature control device 1 by detecting the temperature state of the target controlled by the temperature control device 1. The temperature detection unit 4 outputs the detected temperature information to the temperature control device 1.

  The control unit 5 controls the adjustment valve 3. The amount of refrigerant circulating in the refrigerant circulation path 2 is controlled by controlling the degree of opening of the control valve 3 and the like. By controlling the amount of refrigerant, the temperature of the temperature maintenance chamber 7 by the heat exchanger 6 is controlled near the target temperature. At this time, the control unit 5 changes a change period (hereinafter referred to as “first period”) from a first temperature that is a predetermined temperature higher than the target temperature that is a target value maintained in the temperature maintenance chamber 7 to a second temperature that is lower than the target temperature by a predetermined temperature. The control valve 3 is adjusted based on PID control. On the other hand, in the change period from the second temperature to the first temperature (hereinafter referred to as “second period”), the control unit 5 reduces the open state of the control valve 3.

  PID control is a mechanism known as proportional-integral-derivative control, and the control unit 5 controls the degree of opening of the control valve 3 using this PID control in the first period. When performing PID control, the degree of temperature change is moderated, unlike the simple opening of the control valve 3. The temperature maintenance chamber 7 is often maintained at a temperature lower than the outside air temperature as a target temperature. The first period is a temperature change period of the temperature maintenance chamber 7 when the target temperature is aimed from a state higher than the target temperature. At this time, if the circulation of the refrigerant stops when the target temperature is reached, the heat exchange in the heat exchanger 6 ends, and the temperature of the temperature maintenance chamber 7 immediately exceeds the target temperature. For this reason, it is preferable that the refrigerant circulates and heat exchange (cooling) by the heat exchanger 6 is maintained up to a second temperature lower than the target temperature.

  Based on these situations, the control unit 5 opens the control valve 3 at the first temperature higher than the target temperature (the state in which it is necessary to reduce the temperature of the temperature maintaining chamber 7 by circulating the refrigerant) and Start circulation. When the refrigerant circulation is performed, heat exchange by the heat exchanger 6 is performed and the temperature of the temperature maintaining chamber 7 is lowered. In the graph of FIG. 2, the temperature decreases in the first period. This state continues until the second temperature lower than the target temperature. In the first period, the control unit 5 controls the control valve 3 by PID control. Since the PID control uses proportional integral differentiation including a predetermined correction rather than simply opening the control valve 3, the temperature change becomes gentle during the control period by the PID control.

  The controller 5 reduces the opening of the control valve 3 in the second period. Due to the reduction, the amount of refrigerant circulating in the refrigerant circulation path 2 is reduced, and heat exchange in the temperature maintaining chamber 7 via the heat exchanger 6 is reduced. As a result, the temperature of the temperature maintenance chamber 7 gradually increases from the second temperature, and eventually reaches the first temperature above the target temperature. When the first temperature is reached, the control unit 5 controls the control valve 3 again based on the PID control. The control valve 3 is opened, the refrigerant circulates through the refrigerant circulation path 2, and the temperature of the temperature maintenance chamber 7 decreases via the heat exchanger 6. That is, the first period is started again.

  Here, in the first period under the control by PID control, the temperature change becomes gentle. In addition, also in the second period, the controller 5 does not stop the rotation speed of the compressor 8, but reduces the opening of the control valve 3, so that the refrigerant circulation does not stop suddenly. For this reason, the temperature change in the second period also becomes moderate. As shown in the graph of FIG.

  The fact that the temperature change in the first period and the second period is gradual means that the temperature control device 1 keeps the temperature of the temperature maintenance chamber 7 at the target temperature (the equipment having the temperature maintenance chamber 7 is in operation). The number of cycles in the first period and the second period is reduced. When the number of cycles is small, the period during which the compressor 8 is operating, the number of times the compressor 8 is started, and the starting time of the compressor 8 are reduced. As a result, facilities such as a refrigeration facility including the temperature control device 1 can reduce power consumption. Naturally, refrigeration equipment and refrigeration equipment with low power consumption are useful for environmental protection and cost reduction.

  The graph of FIG. 2 also shows a curve when the compressor 8 is operated and stopped. Compared with this curve, the number of cycles in the first period and the second period is the temperature control of the first embodiment. It can be seen that there is less in the device 1. This graph also shows that the power consumption of the facility using the temperature control device 1 is reduced.

  Moreover, the temperature control apparatus 1 controls not the number of rotations of the compressor 8 as in the prior art but the amount of refrigerant that is sent from the compressor 8 and circulated. In a refrigeration apparatus or a refrigeration facility that is constructed and used as a facility in a factory or business, the compressor 7 is often a commercially available compressor. A commercially available compressor has a function of stopping or restarting its operation (rotation) by the pressure of a refrigerant that recirculates to the compressor (often a vaporized refrigerant that is vaporized). There are many cases. Since such a commercially available compressor is often used as the compressor 8 of the refrigeration apparatus or the refrigeration apparatus to which FIG. 1 is applied, the temperature control apparatus 1 does not control the rotational speed of the compressor 8. difficult. This is because it is necessary to modify the compressor 8 and the like, which is related to the construction cost and period, the reliability of the refrigeration equipment to be constructed, and the like.

  On the other hand, the temperature control device 1 in the first embodiment controls the amount of refrigerant circulating through the refrigerant circulation path 2 instead of the compressor 8, so there is no need for such modification. As a result, it has a positive effect on the cost, period, and reliability in refrigeration equipment and refrigeration equipment construction including the temperature control device 1. In addition, by controlling the amount of the refrigerant circulating in the refrigerant circulation path 2 through the control of the control valve 3 instead of controlling the rotation of the compressor 8, the number of operation and stop cycles of the compressor 8 can be reduced. You can also. As a result, the facility in which the temperature control device 1 is used can reduce power consumption due to the cycle of the compressor 8. Further, since the number of operation / stop cycles of the compressor 8 is reduced, the burden on the compressor 8 can be reduced. If the burden on the compressor 8 is reduced, there is an advantage that the life as equipment of the refrigeration equipment and the refrigeration equipment is extended.

  Thus, the temperature control apparatus 1 of Embodiment 1 can reduce the power consumption of the facility in which the temperature control apparatus 1 is used by the function of controlling the control valve 3 instead of the compressor 8 and the control function by PID control. . In addition, the cost, construction period, life span, reliability, and the like of the refrigeration equipment and refrigeration equipment can be increased.

  Next, the detail of each part is demonstrated.

(Compressor)
The compressor 8 is an element having a function of circulating the refrigerant. A compressor that is generally used or commercially available may be used. The compressor 8 may further include a condenser, and the refrigerant that is refluxed as a gas is condensed and liquefied by the condenser. The compressor 8 sends the liquefied liquid refrigerant to the refrigerant circuit 2. As described above, the compressor 8 sends the liquid refrigerant to the refrigerant circulation path 2 and receives the reflux of the gaseous refrigerant.

  The compressor 8 may send out the refrigerant by various mechanisms. In order to send out the refrigerant, it has a rotating operation, and the delivery amount can be controlled by this rotational speed. Commercially available compressors have various characteristics, but often control rotation to reduce power consumption. In particular, the compressor often stops or restarts its rotation depending on the pressure of the refluxing gaseous refrigerant. For example, the compressor stops rotating when the pressure of the refluxing gaseous refrigerant decreases. On the other hand, when the pressure of the refluxing gaseous refrigerant increases, the compressor resumes rotation. In the refrigeration facility and the refrigeration facility shown in FIG. 1, a temperature maintenance room required in a factory or business office is constructed while combining various commercially available elements. For this reason, since the compressor used is also a commercially available one, the compressor 8 stops or restarts the operation according to the pressure of the refluxing gaseous refrigerant.

  When the control valve 3 is controlled by the control unit 5, the amount of the circulating refrigerant changes, and as a result, the pressure of the gaseous refrigerant that recirculates also changes. The operation of the compressor 8 is stopped or restarted according to this pressure change. Since the temperature control device 1 does not directly control the compressor 8, there is no need to improve the compressor 8, and the construction cost is reduced.

(Refrigerant circuit)
The refrigerant circulation path 2 is connected to the compressor 8 and circulates the refrigerant sent from the compressor 8. The refrigerant circuit 2 circulates the liquid refrigerant to the heat exchanger 6. The heat exchanger 6 reduces the temperature of the temperature maintenance chamber 7 using the heat of vaporization of the refrigerant. That is, the refrigerant is vaporized by the heat exchanger 6. The refrigerant circulation path 2 circulates the vaporized refrigerant and returns it to the compressor 8. Thus, the refrigerant circulation path 2 circulates the liquid refrigerant and the gaseous refrigerant. For this reason, the refrigerant circulation path 2 is connected to the compressor 8 and the heat exchanger 6.

  The refrigerant circulation path 2 may be formed of a metal pipe, a resin pipe, or an alloy pipe, but a metal pipe is often used in consideration of durability, strength, and the like. The refrigerant circulation path 2 is constructed together with the temperature maintenance chamber 7. Since the refrigerant circulation path 2 often depends on the structure of the factory or business place where the refrigeration equipment or refrigeration equipment is constructed, it may be arranged according to the structure of the factory or business place. Alternatively, an already constructed pipe line may be used as the refrigerant circulation path 2.

(Control valve)
The adjustment valve 3 adjusts the amount of refrigerant circulating in the refrigerant circulation path 2. The control valve 3 is provided in the refrigerant circulation path 2 and adjusts the degree of circulation opening in a portion of the refrigerant circulation path 2. When the control valve 3 is closed, a part of the refrigerant circulation path 2 is closed, and the circulation of the refrigerant is stopped (the refrigerant cannot pass through the control valve 3). When the control valve 3 is opened, the refrigerant circulates through the refrigerant circulation path 2. Depending on the degree of opening of the control valve 3, the amount of refrigerant passing through the portion of the refrigerant circuit 2 provided with the control valve 3 changes.

  Thus, the amount of refrigerant circulating through the refrigerant circulation path 2 can be adjusted by adjusting the degree of opening of the control valve 3. If the amount of refrigerant can be adjusted, the pressure of the refrigerant returning to the compressor 8 can also be controlled. As a result, the operation of the compressor 8 is also controlled by adjusting the control valve 3.

  The control valve 3 may be configured by a member that adjusts the degree of opening inside the refrigerant circulation path 2 or may be configured by an electronic device such as an electromagnetic valve. In any case, any valve may be used as long as it is provided at a portion of the refrigerant circulation path 2 and has a mechanism capable of adjusting the amount of refrigerant passing therethrough.

(Heat exchanger)
The heat exchanger 6 uses the refrigerant circulating in the refrigerant circulation path 2 to maintain the temperature inside the temperature maintenance chamber 7 near the target temperature. The heat exchanger 6 is installed inside the temperature maintenance chamber 7 and reduces the ambient temperature by the heat of vaporization of the circulating refrigerant. For the heat exchanger 6, various known members may be used. For example, a member in which the refrigerant circulation path 2 is connected to a metal plate material having high thermal conductivity and the refrigerant circulates inside the plate material may be used.

  FIG. 3 is a front view of the heat exchanger 6 according to Embodiment 1 of the present invention. FIG. 3 shows an example of the heat exchanger 6. The heat exchanger 6 includes a plate material 61 and an internal circulation path 62 inside the plate material 61. The internal circulation path 62 is indicated by a broken line. The internal circulation path 62 is connected to the refrigerant circulation path 2, and the refrigerant that has circulated through the refrigerant circulation path 2 circulates inside the internal circulation path 62. At this time, the refrigerant is input from the inlet 21 and is output from the outlet 22. Since the internal circulation path 62 is provided in a state of circling the inside of the plate member 61, the area in which the refrigerant in the heat exchanger 6 is in thermal contact with the outside becomes large. Due to this large contact area, the heat exchanger 6 vaporizes the refrigerant and lowers the ambient temperature.

  The heat exchanger 6 may be provided inside the temperature maintenance chamber 7 as shown in FIG. 1, but may be integrated with the wall surface of the temperature maintenance chamber 7 or provided outside the temperature maintenance chamber 7 and indirectly. Alternatively, the inside of the temperature maintenance chamber 7 may be cooled.

  The heat exchanger 6 may have a blower fan or the like. The blower fan sends wind to the surface of the heat exchanger 6, and the wind causes the cooling air from the heat exchanger 6 to spread throughout the temperature maintenance chamber 7 throughout the temperature maintenance chamber 7. As a result, the cooling effect in the temperature maintaining chamber 7 is increased, and the cooling capacity of the temperature maintaining chamber 7 by the refrigerant circulation is increased. When such a blower fan is provided in the heat exchanger 6, the cooled air circulates inside the temperature maintenance chamber 7. For this reason, the cool air sent out from the heat exchanger 6 cools while circulating the entire temperature maintenance chamber 7. The cold air returns to the heat exchanger 6 again according to the air flow generated by the blower fan while circulating inside the temperature maintenance chamber 7. That is, the cold air circulates so as to be sucked into the heat exchanger 6.

  Thus, the heat exchanger 6 maintains the temperature maintenance chamber 7 in the vicinity of the target temperature by the action of the circulating refrigerant. The heat exchanger 6 may be integrated with the refrigerant circulation path 2 or may be a separate body. Similarly, the heat exchanger 6 may be integrated with the temperature maintenance chamber 7 or may be a separate body.

(Temperature maintenance room)
The temperature maintenance chamber 7 is a space in which the internal temperature is maintained near a predetermined target temperature by the temperature control device 1 (and the compressor 8 and the heat exchanger 6 that perform an actual cooling function). The temperature maintenance room 7 is an element that becomes a refrigeration room such as a refrigeration facility installed and installed in a factory or business place. For this reason, the temperature maintenance chamber 7 is at least one of a refrigerator compartment, a freezer compartment, and a temperature-controlled room. It is a space constructed for any of these purposes.

  Moreover, the temperature maintenance room 7 may be a space (equipment) newly constructed in accordance with construction of a refrigeration facility, a freezing facility, or the like, or a space already provided in a factory or business place is used. That's fine. The temperature control device 1 is finally combined with the temperature maintenance chamber 7 to construct a refrigeration facility or a refrigeration facility.

  Since the temperature maintaining chamber 7 needs to be cooled, the temperature maintaining chamber 7 includes the heat exchanger 6 described above, and at least a part of the refrigerant circulation path 2 is provided as necessary. The control unit 5 may be installed inside or outside the temperature maintenance chamber 7. For example, the control unit 5 may be installed on the wall surface of the temperature maintenance chamber 7.

  Since the temperature maintenance chamber 7 is constructed and maintained at a target temperature in a factory or business place, it is preferable that the temperature maintenance chamber 7 is formed of a material having high heat insulation. For example, it is appropriate to be surrounded by concrete. Of course, it may be surrounded by a metal plate.

  Whether the temperature maintenance room 7 is used as a refrigerator room, a freezer room, or a temperature-controlled room may be determined by the structure and material of the temperature maintenance room 7 itself, and the structure and material of the temperature maintenance room 7 as equipment are as follows: In common, depending on the temperature characteristics controlled by the compressor 8 and the temperature control device 1, it may be determined whether the temperature maintenance chamber 7 is used as a refrigerator compartment, a freezer compartment, or a temperature-controlled room. That is, even if the temperature maintaining chamber 7 is the same, the temperature maintaining chamber 7 is used as one of the refrigerator compartment, the freezer compartment, and the temperature-controlled room depending on the target temperature (value and characteristics) set by the temperature control device 1. There can be.

  It is also useful for the entire facility that the temperature maintenance chamber 7 has strength and durability in addition to heat insulation.

(Control part)
The control unit 5 controls the degree of opening of the control valve 3. If the opening degree of the control valve 3 is controlled, the amount of refrigerant circulating in the refrigerant circulation path 2 varies, and the inside of the temperature maintenance chamber 7 is cooled or not cooled by the heat exchanger 6. As a result, the temperature control device 1 can maintain the temperature maintaining chamber 7 near the target temperature without performing the compressor 8 and the refrigerant circulation in full time. In practice, as shown in FIG. 2, the temperature control device 1 controls the temperature maintaining chamber 7 so as to swing within the range before and after the target temperature (the range depending on the first temperature and the second temperature).

  The control unit 5 controls the control valve 3 according to PID control in the first period. In the first period, the control unit 5 opens the adjustment valve 3 and allows the refrigerant to pass through the adjustment valve 3 in the refrigerant circulation path 2. That is, the refrigerant is circulated in the refrigerant circulation path 2. As a result, the refrigerant circulates through the refrigerant circulation path 2, and the temperature of the temperature maintenance chamber 7 decreases (as shown in FIG. 2). Here, in the control of the control valve 3 according to the PID control, the control unit 5 controls the amount of refrigerant passing through the control valve 3 by varying the degree of opening of the control valve 3 by various methods. By appropriately controlling the amount of the refrigerant, a rapid temperature drop is prevented in the first period, or overcooling that reaches the second temperature or less is prevented. As a result, the number of rotations of the compressor 8 is also reduced and power consumption is reduced.

  In the second period, the control unit 5 reduces the pressure of the circulating refrigerant by reducing the opening of the control valve 3. Thereby, in the second period, the temperature is gradually increased, and the compressor 8 is stopped due to the pressure drop of the refrigerant returning to the compressor 8. As described above, the gradual temperature change in the second period and the stoppage of the compressor 8 reduce the power consumption of the refrigeration equipment including the compressor 8 and the like.

  The control unit 5 controls the control valve 3 in the first period by various methods.

(Control in the first period)
First, control of the control valve 3 in the first period by the control unit 5 will be described.

(Opening / closing control of control valve 3)
As an example, the control unit 5 can control the amount of refrigerant that passes through the control valve 3 per unit time by opening and closing the control valve 3. Since the control valve 3 is opened and closed, the amount of refrigerant passing therethrough decreases as a result of repeated opening and closing compared to the open state. As a result, the amount of refrigerant passing through the refrigerant circuit 2 decreases. If it decreases, the heat exchange capacity in the heat exchanger 6 decreases, and the temperature inside the temperature maintenance chamber 7 gradually rises as shown by the rising curve in FIG.

  FIG. 4 is a graph showing opening and closing of the control valve in Embodiment 1 of the present invention. FIG. 4 shows a case where the control valve 3 is in an open state and a case where the control valve 3 repeatedly opens and closes. 4A is the former, and FIG. 4B is the latter. In each graph of FIG. 4 (A) and FIG. 4 (B), the horizontal axis represents time, and the vertical axis represents the degree of opening of the control valve 3. The upper part of the vertical axis indicates a state in which the control valve 3 is largely opened (shows a state in which the amount of refrigerant passing through the control valve 3 is large). The horizontal axis is a time axis, but is defined in the graph of FIG. 4 with a certain time width as a unit time.

  In each graph of FIG. 4 (A) and FIG. 4 (B), a curve 51 indicates a change in the degree of opening of the control valve 3. In FIG. 4A, the control valve 3 maintains a sufficiently open state, so the curve 51 is in a straight line state. In other words, control that only opens the control valve 3 is shown, such as so-called ON control.

  In FIG. 4A, since the regulating valve 3 is opened as shown by a curve 51, the refrigerant passes through the regulating valve 3 according to the opening. A region 52 indicates the amount of refrigerant that passes in accordance with the opening of the control valve 3. As can be seen from the region 52 in FIG. 4A, the amount of refrigerant passing through the control valve 3 per unit time is large. As a result, the amount of the refrigerant circulating in the refrigerant circulation path 2 increases, and the cooling of the temperature maintenance chamber 7 via the heat exchanger 6 proceeds at a stretch and falls below the target temperature in a short time.

  On the other hand, the open / closed state of the control valve 3 in FIG. 4B is an example of control of the control valve 3 by the control unit 5 in the first period. The controller 5 controls the amount of refrigerant that passes through the unit time by repeatedly opening and closing the control valve 3. By controlling the amount of refrigerant passing therethrough, it is possible to prevent the temperature of the temperature maintaining chamber 7 from being rapidly lowered. A curve 51 in FIG. 4B shows a state where the control valve 3 repeats opening and closing. Region 52 indicates that the refrigerant is passing when the control valve 3 is open, and indicates that no refrigerant is passing when the control valve 3 is closed. That is, when viewed in unit time, the amount of refrigerant passing through the control valve 3 is relatively smaller than when the valve is simply opened. When the amount of refrigerant passing therethrough is small, the amount of refrigerant circulating in the refrigerant circulation path 2 is small, and the temperature maintenance chamber 7 is gradually cooled via the heat exchanger 6. As a result, as shown in the graph of FIG. 2, the temperature of the temperature maintaining chamber 7 changes gradually from the first temperature to the second temperature. This indicates that the rotational speed and operation load in the compressor 8 are reduced, and the power consumption is reduced.

  As described above, the control unit 5 can control the amount of refrigerant passing through the control valve 3 in unit time by controlling the opening and closing of the control valve 3. That is, in the first period, as shown in the graph of FIG. 4B, the control unit 5 controls the control valve 3 to control the refrigerant circulation amount, from the first temperature to the second temperature. Control the temperature change of In the first period, since the refrigerant circulation amount decreases, the pressure of the vaporized refrigerant flowing back to the compressor 8 decreases. As a result, the power consumption of the compressor 8 is also reduced.

  In addition, regarding opening and closing, opening means not only that the control valve 3 is completely opened, but indicates an opened state that can accommodate the passage of refrigerant, and closing means that the valve is completely closed. It is not limited to this, and it shows that the refrigerant is in a state that is difficult to pass through.

(Control valve opening area control)
As another example, the control unit 5 controls refrigerant circulation in the first period by controlling the amount of refrigerant passing through the regulating valve 3 per unit time by controlling increase / decrease in the opening area of the regulating valve 3. To do. When the control valve 3 is provided in the refrigerant circuit 2, the control valve 3 can adjust the degree of opening in a part of the refrigerant circuit 2. That is, the control valve 3 can serve as an open / close door at a position where the refrigerant circulation path 2 is located. For this reason, the regulating valve 3 can vary the amount of refrigerant passing through the regulating valve 3 by adjusting the opening area.

  FIG. 5 is a graph for explaining control of the control valve according to Embodiment 1 of the present invention. FIG. 5 shows a case where the control unit 5 increases or decreases the opening area of the control valve 3, unlike FIG. 4. FIG. 5 (A) shows a case where the control valve 3 maintains a constant open state, as in the case of FIG. 4 (A). For this reason, the amount of refrigerant passing through the control valve 3 per unit time is constant and increases as a whole.

  FIG. 5B shows a state where the control unit 5 increases or decreases the opening area of the control valve 3. A curve 51 in FIG. 5B shows an increase / decrease state. Since the open state of the control valve 3 follows this curve 51, an amount of refrigerant corresponding to the region 52 such as a half-moon shape passes through the control valve 3. As can be seen by comparing FIG. 5 (A) and FIG. 5 (B), the region 52 in FIG. 5 (B) is small, and the amount of refrigerant passing in a unit time decreases with the increase / decrease in the opening area. I understand. As the amount of refrigerant per unit time decreases, the temperature of the temperature maintenance chamber 7 gradually decreases during the first period. That is, the first temperature changes to the second temperature. Of course, since it changes slowly, less power is required.

  As described above, the control unit 5 controls the amount of refrigerant passing through the control valve 3 per unit time by controlling the degree of opening of the control valve 3 in various ways. Of course, it may be controlled by methods other than those described above.

(Control in the second period)
Next, control in the second period will be described.

  The controller 5 reduces the opening of the control valve 3 in the second period. Since the opening of the control valve 3 can be reduced, the amount of refrigerant circulating in the refrigerant circulation path 2 is reduced. As the amount of refrigerant decreases, the pressure of the refrigerant returning to the compressor 8 decreases. Due to the decrease in pressure, the compressor 8 stops or the rotational speed is reduced. As a result, in the second period, the temperature gradually increases as shown in the graph of FIG. The temperature rises from the second temperature to the first temperature. If it raises to 1st temperature, the control part 5 will circulate a refrigerant | coolant by PID control again.

  Here, not only the opening of the control valve 3 is reduced, but the control unit 5 may close the control valve 3. By closing, the amount of refrigerant passing through the control valve 3 is almost eliminated, and the cooling of the temperature maintaining chamber 7 via the heat exchanger 6 is weakened. Further, the compressor 8 often has a function of stopping its rotation when the pressure of the recirculating refrigerant is equal to or lower than a predetermined value. For this reason, the control part 3 closes the control valve 3, and the pressure of the refrigerant | coolant which recirculate | refluxs to the compressor 8 reduces. As a result, the compressor 8 stops and power consumption can be reduced.

  Thus, in the second period, the control unit 5 reduces the amount of refrigerant passing therethrough by reducing the opening of the control valve 3 or closing the control valve 3 in some cases, so that the temperature falls below the second temperature. The entire power consumption is reduced while preventing the temperature of the maintenance chamber 7 from decreasing.

  In addition, as shown in the graph of FIG. 2, it is preferable that the difference value between the first temperature and the target temperature is larger than the difference value between the second temperature and the target temperature. For example, in the graph of FIG. 2, the target temperature is 5 ° C., the first temperature is 1 ° C. higher 6 ° C., and the second temperature is 0.8 ° C. lower 4.2 ° C. Thus, since the difference value of 1st temperature and target temperature is larger than the difference value of 2nd temperature and target temperature, the temperature fall in the 1st period when a temperature change arises because refrigerant circulation is performed more. It becomes gradual and overcooling is prevented. This is because in the first period, the refrigerant circulation is performed and the temperature lowers more artificially. This is because if the second temperature, which is the threshold value for the first period, is set in the same manner as the first temperature, there is a possibility that a positive temperature decrease due to the refrigerant circulation will be excessive.

  On the other hand, in the second period, the temperature naturally increases as the refrigerant circulation is reduced or stopped. For this reason, even if the difference value between the first temperature and the target temperature at the end of the second period is large, a problem hardly occurs. From these, it is also preferable that the difference value between the first temperature and the target temperature is larger than the difference value between the second temperature and the target temperature.

  As described above, the temperature control device 1 according to Embodiment 1 is suitably used in facilities that are constructed using a commercially available compressor 8 or the like, such as a refrigeration facility, a refrigeration facility, and a constant temperature facility. In addition, by controlling the control valve 3 separately in the first period and the second period, the number of cycles of temperature change can be reduced, and the power consumption of the entire facility can be reduced.

(Embodiment 2)
Next, a second embodiment will be described. In the second embodiment, a device for installing the temperature detection unit 4 will be described.

  The temperature detection unit 4 detects the temperature of the temperature maintenance chamber 7 and notifies the control unit 5 of the detection result. The controller 5 extracts the first temperature and the second temperature at the temperature notified by the temperature detector 4, and performs the control in the first period and the second period described in the first embodiment. For this reason, the temperature of the temperature maintenance chamber 7 detected by the temperature detection unit 4 requires high accuracy.

  As an example, the temperature detection unit 4 is preferably located at the rear end of the air circulation inside the temperature maintenance chamber 7. In the temperature maintenance chamber 7, air circulates in the interior as the heat exchanger 6 exchanges heat. Convection caused by cold and warm air creates this air circulation. FIG. 6 is a schematic diagram of the refrigeration facility according to Embodiment 2 of the present invention. In FIG. 6, the temperature detection unit 4 is located at the rear end of the air circulation 71. The air circulation 71 starts to circulate from the heat exchanger 6 and returns to the heat exchanger 6 as shown by the broken arrow, and the circulation ends. The region where the circulation ends is the rear end of the air circulation. Of course, the air circulation is connected, but for the sake of clarity, the broken line arrow is stopped after about one round.

  Here, at the initial end of the air circulation (in FIG. 6, the start portion of the air circulation 71, which is a broken-line arrow), cold air from the heat exchanger 6 is generated. For this reason, the temperature tends to be detected lower than the temperature of the entire temperature maintaining chamber 7. Even if the temperature detection unit 4 is installed at this position, it is difficult to detect the accurate temperature of the temperature maintenance chamber 7. On the other hand, the end of the air circulation 71 indicated by the broken-line arrow is a portion that returns to the heat exchanger 6. This is the rear end of the air circulation. Here, since the air after the air circulation is completed exists, it is considered that the temperature of the temperature maintenance chamber 7 is reflected more accurately.

  Alternatively, if the heat exchanger 6 performs exhaust and intake, the temperature detection unit 4 is located on the intake side of the heat exchanger 6. Also in this case, since the temperature detection unit 4 is installed at a position where the air circulating through the entire temperature maintenance chamber 7 exists, the temperature detection unit 4 more accurately determines the temperature of the temperature maintenance chamber 7. It can be detected.

  As described above, the temperature detection unit 4 is located at the rear end of the air circulation 71 or is located on the intake side of the heat exchanger 6 so as to detect and control the temperature of the temperature maintaining chamber 7 more accurately. Part 5 can be notified.

(Embodiment 3)
Next, Embodiment 3 will be described. In the third embodiment, a case where a buffer tank is further provided in the refrigerant circulation path 2 will be described. FIG. 7 is a block diagram of the temperature control apparatus and the temperature maintenance facility including the periphery thereof according to Embodiment 3 of the present invention. The same elements as those described with reference to FIG.

  In the temperature maintenance facility of FIG. 7, a buffer tank 9 is provided in the middle of the refrigerant circulation path 2 and at a position where the refrigerant returns to the compressor 8. Since the buffer tank 9 is provided in the middle of the refrigerant circuit 2, the pipe of the refrigerant circuit 2 is input to the buffer tank 9, and the pipe of the refrigerant circuit 2 is output again. The pipe line that outputs the buffer tank 9 is connected to the compressor 8.

  The buffer tank 9 has a storage capacity having a predetermined capacity, and can store the vaporized refrigerant that has circulated through the refrigerant circulation path 2. That is, in the refrigerant circulation path 2, after passing through the heat exchanger 6, the refrigerant is vaporized to become a vaporized refrigerant. The vaporized refrigerant returns to the compressor 8 and is temporarily stored in the buffer tank 9 in the middle thereof. For this reason, the buffer tank 9 has a constant pressure as long as it contains the vaporized refrigerant.

  Further, since the buffer tank 9 is connected to the compressor 8 by the refrigerant circulation path 2, the buffer tank 9 contains the vaporized refrigerant accommodated so as to protrude if there is vaporized refrigerant that is input. Is output. The outputted refrigerant reaches the compressor 8. That is, the buffer tank 9 has a constant pressure as long as it contains the refrigerant.

  In the second period, the control unit 5 reduces or closes the opening of the control valve 3. As a result, the refrigerant circulating in the refrigerant circulation path 2 is eventually reduced. When the refrigerant circulating in the refrigerant circulation path 2 decreases, the pressure of the refrigerant returning to the compressor 8 also decreases. When the pressure of the refrigerant returning to the compressor 8 becomes a predetermined position or less, the compressor 8 stops its operation. That is, in the second period, the compressor 8 stops after a certain amount of time has elapsed. Here, if the compressor 8 is frequently stopped, the compressor 8 has to perform a restart operation when shifting from the second period to the first period. The resuming operation of the compressor 8 increases power consumption and increases the burden on the compressor 8.

  On the other hand, when the buffer tank 9 is provided, even if the control unit 5 reduces or closes the opening of the control valve 3 in the second period, the buffer tank 9 stores a predetermined amount of refrigerant in a certain time. Therefore, a predetermined pressure is maintained for the compressor 8. This is because the pressure of the refrigerant stored in the buffer tank 9 continues to be applied to the compressor 8 even after the control valve 3 is closed.

  Even after the regulating valve 3 is closed in this manner, the compressor 8 does not have to stop its operation by continuously applying pressure to the compressor 8. Or even if it stops, the frequency | count reduces. On the other hand, the control unit 5 can reduce or close the opening of the control valve 3 in the second period according to the detected temperature, so that the temperature change in the second period is guaranteed. In this state, the number of stoppages of the compressor 8 decreases, so that an increase in power consumption and an increase in load on the compressor 8 due to the restart operation of the compressor 8 are prevented.

  As described above, the buffer tank 9 can store a predetermined amount of the refrigerant, so that the pressure on the compressor 8 can be maintained for a predetermined time. By maintaining this pressure, the frequency of stoppage of the compressor 8 can be reduced, and the movable life can be extended while reducing power consumption in the entire temperature maintenance facility.

  The size of the buffer tank 9 (the amount of refrigerant accommodated) may be determined as appropriate. In particular, from the relationship between the value of the pressure at which the compressor 8 is stopped and the volume of the refrigerant circulation path 2, it is preferable that the compressor 8 has a size capable of maintaining a pressure at which the compressor 8 does not stop.

  In the buffer tank 9, it is preferable that the refrigerant circulation path 2 be input from the bottom surface of the buffer tank 9 and output from the bottom surface. That is, it is preferable that the refrigerant circulation path 2 feeds the vaporized refrigerant from the bottom surface of the buffer tank 9 and the refrigerant sent from the buffer tank 9 outputs the refrigerant circulation path 2 from the bottom surface of the buffer tank 9. By inputting the refrigerant from the bottom surface and outputting from the bottom surface, the refrigerant corresponding to the capacity of the buffer tank 9 is accommodated in the buffer tank 9.

  As described above, since the buffer tank 9 is provided in the middle of the refrigerant circulation path 2 and before returning to the compressor 8, the stop frequency of the compressor 8 can be reduced, resulting in reduction of power consumption and movable life. Can be extended.

(Embodiment 4)
Next, a fourth embodiment will be described.

  In the fourth embodiment, a temperature control device that further includes a second control unit that controls humidity and atmospheric pressure inside the temperature maintenance chamber 7 will be described. FIG. 8 is a block diagram of a temperature maintenance facility according to Embodiment 4 of the present invention. The temperature maintenance facility 100 includes the temperature control device 1 and the compressor 8, and maintains the temperature inside the temperature maintenance chamber 7 at a target temperature. Here, the temperature control device 1 further includes a second control unit 11. The second control unit 11 controls the humidity and atmospheric pressure inside the temperature maintenance chamber 7.

  The temperature maintenance room 7 is applied to a refrigerator room, a freezer room, a temperature-controlled room, and the like. That is, the temperature maintenance facility 100 of FIG. 8 is applied to a refrigeration facility, a refrigeration facility, and a constant temperature facility. At this time, when used in a refrigerator compartment or a freezer compartment, it may be preferable that the temperature maintenance chamber 7 also controls humidity and atmospheric pressure. Moreover, it is also suitable that these humidity and atmospheric | air pressure are controlled based on the temperature inside the temperature maintenance chamber 7. FIG. The second control unit 11 controls the humidity and atmospheric pressure inside the temperature maintenance chamber 7 based on the detection result of the temperature detection unit 4.

  Various methods may be used in controlling the humidity and atmospheric pressure by the second control unit 11. By controlling the humidity and pressure, the atmosphere control inside the temperature maintenance chamber 7 is further improved.

(Embodiment 5)
Next, a fifth embodiment will be described. In the fifth embodiment, a temperature maintenance facility including the temperature control device described in the first to fourth embodiments will be described. FIG. 9 is a schematic diagram of a temperature maintenance facility according to Embodiment 5 of the present invention. The temperature maintenance facility 100 is constructed and installed in a factory or business place. A base of the temperature maintenance facility 100 is formed by using a space, a warehouse, or the like provided in a factory or business office as the temperature maintenance room 7 or by newly constructing the temperature maintenance room 7.

  As the compressor 8, a commercially available compressor 8 is selected and installed based on the size and specifications of the temperature maintenance chamber 7. The refrigerant circulation path 2 extends from the compressor 8 and is connected to the heat exchanger 6 provided in the temperature maintenance chamber 7 to supply the refrigerant to the heat exchanger 6. The refrigerant circulation path 2 includes a control valve 3 in the middle, and the degree of opening is controlled by the control unit 5. By these assembly, the temperature maintenance equipment 100 is constructed and installed. As described in the first to fourth embodiments, the temperature control device 1 can optimally maintain the inside of the temperature maintenance chamber 7 near the target temperature while reducing the power consumption including the compressor 8.

  The temperature maintenance facility 100 is used as at least one of a refrigeration facility, a refrigeration facility, and a constant temperature facility depending on the characteristics of the temperature maintenance chamber 7.

  The temperature maintenance facility 100 may be designed and constructed from the beginning, including the temperature maintenance chamber 7, or after only the temperature maintenance chamber 7 is constructed, the compressor 8 and the temperature control device 1 may be replaced by another contractor. May be constructed, or a contractor may construct only the temperature control device 1. Alternatively, all the elements may be manufactured in a factory or the like and transported to the site, and a contractor may assemble each element. In this case, only the temperature control device 1 may be installed and adjusted by a certain contractor.

  Further, even after the temperature maintenance facility 100 of FIG. 9 has been constructed and operated, when an element needs to be replaced, it is only necessary to replace or repair the element. The advantage is that all elements are not integrated. In particular, the independent maintenance of the temperature control device 1 is advantageous in that the temperature maintenance facility 100 is used for a long period of time.

  In this way, the temperature maintenance facility 100 is designed and constructed as independent elements of the temperature maintenance chamber 7, the compressor 8, the buffer tank 9, and the temperature control device 1, and thus has high maintainability and can be used for various purposes. Optimal for the scale.

  As described above, the temperature control device and the temperature maintenance facility described in the first to fifth embodiments are examples for explaining the gist of the present invention, and include modifications and alterations without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Temperature control apparatus 2 Refrigerant circuit 3 Control valve 4 Temperature detection part 5 Control part 6 Heat exchanger 7 Temperature maintenance room 8 Compressor 9 Buffer tank

Claims (17)

A refrigerant circulation path for circulating the refrigerant delivered from the compressor;
A regulating valve for regulating the amount of refrigerant circulating in the refrigerant circuit;
A temperature detector that measures the temperature of the temperature maintenance chamber maintained near the target temperature by heat exchange of the refrigerant; and
A control unit for controlling the control valve,
In the change period (hereinafter referred to as “first period”) from a first temperature that is higher than the target temperature by a predetermined temperature to a second temperature that is lower than the target temperature by a predetermined temperature, the control unit is based on the PID control method. A temperature control device that controls the control valve to reduce the opening of the control valve during a change period from the second temperature to the first temperature (hereinafter referred to as “second period”).   2. The temperature control device according to claim 1, wherein in the first period, the control unit controls opening and closing of the control valve so as to control an amount of refrigerant passing through the control valve in a unit time.   3. The temperature control device according to claim 2, wherein in the first period, the control unit controls the amount of refrigerant passing through the control valve by opening and closing the control valve.   3. The temperature control device according to claim 2, wherein in the first period, the control unit controls an amount of refrigerant passing through the control valve by increasing or decreasing an opening area of the control valve.   The temperature control device according to claim 3 or 4, wherein the control unit performs opening and closing of the control valve in the first period based on a PID control method.   6. The temperature control device according to claim 1, wherein in the second period, the control unit closes the control valve.   The temperature control device according to any one of claims 1 to 6, wherein the compressor stops rotating when a pressure of the refrigerant returning through the refrigerant circulation path is equal to or lower than a predetermined value.   The temperature control device according to claim 1, wherein the temperature detection unit is located at a rear end of an air circulation in the temperature maintenance chamber.   The temperature control according to any one of claims 1 to 8, further comprising a heat exchanger provided in the temperature maintenance chamber in the middle of the refrigerant circulation path, wherein the temperature detection unit is located on an intake side of the heat exchanger. apparatus.   The temperature control device according to claim 1, wherein a difference value between the target temperature and the first temperature is larger than a difference value between the target temperature and the second temperature.   The temperature control device according to any one of claims 1 to 10, wherein the temperature maintaining chamber is at least one of a refrigerator compartment, a freezer compartment, and a temperature-controlled room.   The temperature control device according to any one of claims 1 to 11, wherein a buffer tank is provided at a position where the refrigerant flows back to the thermal compressor in the refrigerant circulation path.   The temperature control apparatus according to claim 12, wherein the buffer tank temporarily stores a predetermined amount of vaporized refrigerant that recirculates the refrigerant circulation path to the compressor.   The temperature control according to claim 12 or 13, wherein the refrigerant reflux path sends vaporized refrigerant to a bottom surface of the buffer tank, and the buffer tank sends vaporized refrigerant to be stored from the bottom surface of the buffer tank to the compressor. apparatus.   The temperature control apparatus according to claim 1, further comprising a second control unit that controls humidity and atmospheric pressure in the temperature maintenance chamber. A temperature control device according to any one of claims 1 to 15,
A compressor for sending refrigerant to the refrigerant circuit;
A temperature maintenance chamber to be heat-exchanged by the refrigerant circulation path;
A temperature maintenance facility comprising: a heat exchanger that keeps the temperature of the temperature maintenance chamber constant by circulation of the refrigerant.   The temperature maintenance facility according to claim 16, wherein the temperature maintenance facility is at least one of a refrigeration facility, a refrigeration facility, and a constant temperature facility.

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