JP5880975B2 - Control apparatus and control method for refrigeration apparatus, and refrigeration apparatus including the control apparatus - Google Patents

Description

  The present invention relates to a control apparatus and control method for a refrigeration apparatus, and a refrigeration apparatus including the control apparatus, and more particularly, a control apparatus for a refrigeration apparatus that enables a quick and smooth start during a cold start, and The present invention relates to a control method and a refrigeration apparatus including the control device.

Conventionally, an exhaust heat recovery type heat pump has been used as an application of a refrigeration apparatus.
This exhaust heat recovery type heat pump is configured by connecting a compressor, a condenser, an electronic expansion valve whose opening degree is adjusted so that a detected superheat degree becomes a superheat degree set value, and an evaporator in this order, This is a refrigeration apparatus having a refrigerant circuit in which the refrigerant circulates. In particular, in the evaporator, the refrigerant is evaporated by recovering exhaust heat from the heat source fluid using the heat source fluid, and the heat source temperature is high. In connection with this, the evaporation temperature is also high.

In this case, the suction pipe to the compressor is normally heat-insulated, and the flow rate and heat capacity of the suction gas refrigerant are sufficiently large, so that the refrigerant sucked into the compressor undergoes recondensation in steady operation. There is no fear.
However, for example, during cold start in winter, the suction pipe to the compressor and the heat insulating material itself are in equilibrium with the outside air temperature, and the flow rate (heat capacity) of the suction refrigerant gas to the compressor is initially small. The refrigerant gas evaporated in the evaporator is cooled or cooled by the oil temperature in the compressor to re-condense, causing a liquid back to the compressor, shutting down the operation, and in some cases, the compressor May cause damage.

For example, Patent Document 1 discloses a heat pump heat recovery apparatus that solves the technical problem associated with such recondensation of refrigerant.
This heat pump type heat recovery device is configured to include a heat quantity control means for controlling the heat quantity of exhaust heat supplied to the evaporator at the time of starting the apparatus. More specifically, the heat quantity control means supplies the exhaust hot water at the inlet of the evaporator. The circuit consists of a three-way valve that mixes waste water supplied from the outside and waste water that has passed through the evaporator from the waste water outlet circuit at a required ratio. The temperature of the supplied waste water is controlled.

According to such a configuration, before starting the heat recovery operation by the heat pump after the start of operation, the refrigerant evaporation temperature is controlled to be lower than the refrigerant suction pipe temperature or the like or the oil temperature in the compressor, and evaporated by the heat recovery heat exchanger. Since the preheating operation is set to raise the temperature of the refrigerant suction pipe with the overheated refrigerant vapor, the refrigerant is rapidly cooled between the heat recovery heat exchanger and the compressor inlet after the heat recovery operation is started. The heat recovery operation can be started up without the danger that the refrigerant condenses and condenses with oil inside the compressor.

However, such a heat pump type heat recovery apparatus has the following technical problems due to the fact that the evaporator inlet temperature of the heat source side fluid is lowered at the time of starting.
That is, it is difficult to start the heat pump heat recovery device quickly and smoothly.
More specifically, when the evaporator inlet temperature of the heat source side fluid is lowered, the evaporation temperature of the refrigerant gas is lowered, but the refrigerant outlet temperature of the refrigerant is pulled closer to the evaporator inlet temperature of the heat source side fluid. Similarly to the evaporator inlet temperature of the heat source side fluid, the evaporator outlet temperature of the refrigerant gas also decreases.
In this respect, the refrigerant gas flowing out from the evaporator plays a role of heating the suction pipe cooled by the outside air from the inside. When the refrigerant gas evaporator outlet temperature is lowered, it corresponds to heating the suction pipe. Takes a lot of time.

Such a technical problem is not a problem inherent to the heat pump heat recovery device, but generally occurs in a refrigeration facility in which the evaporation temperature of the refrigerant is higher than the outside air temperature during a cold start, for example, a start in winter. It is a problem to get.
JP 2008-8595 A

  In view of the above technical problems, an object of the present invention is to provide a control device and a control method for a refrigeration apparatus that enables quick and smooth start at the time of cold start, and a refrigeration apparatus including the control device. There is to do.

In order to achieve the above object, a control device for a refrigeration apparatus of the present invention comprises:
A compressor, a condenser, an electronic expansion valve whose opening degree is adjusted so that the detected superheat degree becomes a superheat degree set value, and an evaporator are connected in this order, and a refrigerant circuit in which the refrigerant circulates is provided. In the control device of the freezing device,
A superheat setting value for adjusting the superheat setting value for the electronic expansion valve so that the evaporation temperature of the refrigerant in the evaporator is lower than the temperature of the refrigerant suction pipe to the compressor when the refrigeration apparatus is started. It has a configuration having adjustment means.

According to the control device for a refrigeration apparatus having the above-described configuration, when the refrigeration apparatus is started, the superheat degree set value adjusting means causes the refrigerant evaporation temperature in the evaporator to be lower than the temperature of the refrigerant suction pipe to the compressor. By adjusting the superheat setting value for the electronic expansion valve, for example, in the winter, even if the refrigerant suction pipe is cooled by the outside air and the temperature of the refrigerant suction pipe is low, the refrigerant evaporation temperature is It is possible to prevent the liquid back to the compressor due to recondensing of the refrigerant without the need to heat the refrigerant suction pipe separately at the time of start-up, while the operation of the refrigeration apparatus continues. As the refrigerant suction pipe is gradually heated by the refrigerant gas, the refrigeration apparatus is operated with appropriate efficiency by reducing the superheat setting value by the superheat setting value adjusting means. It is possible.

The superheat degree set value adjusting means includes heat source fluid inlet temperature detecting means for detecting an inlet temperature of the heat source fluid in the evaporator,
Refrigerant gas outlet temperature detection means for detecting the outlet temperature of the refrigerant gas in the evaporator;
A temperature difference setting means for setting a temperature difference between the inlet temperature of the heat source fluid detected by the heat source fluid inlet temperature detector and the outlet temperature of the refrigerant gas in the evaporator detected by the refrigerant gas outlet temperature detector;
Refrigerant inlet pipe temperature detecting means for detecting the temperature of the refrigerant inlet pipe;
Anti-condensation temperature margin setting means for setting a temperature margin necessary to prevent condensation of the refrigerant gas flowing out of the evaporator;
Safe evaporation temperature calculation for calculating the safe evaporation temperature of the refrigerant by subtracting the condensation prevention temperature margin set by the condensation prevention temperature margin setting means from the temperature of the refrigerant suction pipe detected by the refrigerant suction pipe temperature detection means Means,
By subtracting the safe evaporation temperature calculated by the safe evaporation temperature calculation means and the temperature difference set by the temperature difference setting means from the inlet temperature of the heat source fluid detected by the heat source fluid inlet temperature detection means, the degree of superheat It is preferable to have superheat degree set value calculating means for calculating the set value.

Furthermore, it is preferable to have a superheat degree set value transmitting means for transmitting the superheat degree set value calculated by the superheat degree set value calculating means to the superheat degree controller of the electronic expansion valve.
In addition, there is further provided a standard superheat degree set value setting means for setting a standard superheat degree set value, and when the superheat degree set value reaches the standard superheat degree set value, the superheat degree setting by the superheat degree set value adjusting means is performed. You may have a superheat degree set value adjustment cancellation | release means to cancel | release adjustment of a value.
Furthermore, the refrigeration apparatus heats water supplied from the outside to the condenser with the latent heat of condensation of the refrigerant in the condenser to supply steam and high-temperature water, and discharges the water supplied from the outside to the evaporator. A heat pump heat recovery apparatus configured to evaporate the refrigerant in the evaporator using heat as a heat source may be used.

Further, the compressor may be a scroll type having no oil sump inside.
The refrigerant suction pipe temperature detecting means may detect an outer wall temperature of the refrigerant suction pipe in the vicinity of the refrigerant suction pipe on the upstream side of the compressor.

  In order to achieve the above object, a refrigeration apparatus of the present invention is configured to include the control device for a refrigeration apparatus according to any one of claims 1 to 7.

In order to achieve the above object, a control method for a refrigeration apparatus of the present invention includes:
A compressor, a condenser, an electronic expansion valve whose opening degree is adjusted so that the detected superheat degree becomes a superheat degree set value, and an evaporator are connected in this order, and a refrigerant circuit in which the refrigerant circulates is provided. In the control method of the freezing device,
Setting a temperature difference between the inlet temperature of the heat source fluid and the outlet temperature of the refrigerant gas in the evaporator, and setting a temperature margin necessary to prevent condensation of the refrigerant gas flowing out of the evaporator;
Detecting the inlet temperature of the heat source fluid in the evaporator and the outlet temperature of the refrigerant gas, and detecting the temperature of the refrigerant suction pipe to the compressor;
Calculating a safe evaporation temperature of the refrigerant by subtracting the set condensation prevention temperature margin from the detected temperature of the refrigerant suction pipe; and
Calculating a superheat setting value by subtracting the calculated safe evaporation temperature and the set temperature difference from the detected inlet temperature of the heat source fluid; and
Thereby, when the refrigeration apparatus is started, the superheat degree set value for the electronic expansion valve is adjusted so that the evaporation temperature of the refrigerant in the evaporator is lower than the temperature of the refrigerant suction pipe to the compressor.

The adjusting step of the superheat setting value may include a step of gradually reducing the superheat setting value in accordance with an increase in the refrigerant suction pipe temperature.
Further, the temperature margin setting step may include a step of gradually reducing the temperature margin in accordance with a decrease in the rising slope of the refrigerant suction pipe temperature.

Embodiments of a control device and a control method for a refrigeration apparatus according to the present invention will be described below in detail with reference to the drawings.
In FIG. 1, the refrigeration apparatus 12 schematically includes the refrigerant outlet pipe 20 having one end connected to the discharge side of the compressor 18, and the other end of the evaporator 16 via a condenser 22 and an electronic expansion valve 24. The other end of the refrigerant return pipe 26 connected to the primary side flow path inlet and connected to one end of the primary side flow path outlet is connected to the suction side of the compressor 18 to constitute a refrigerant circuit. As for the refrigerant, for example, R22 and R23 may be used as chlorofluorocarbons, and ammonia refrigerant and carbon dioxide refrigerant may be used as non-fluorocarbons.

The evaporator 16 is configured as a dry evaporator, and a heat exchange pipe (not shown) connected to the refrigerant circuit 12 is disposed inside the evaporator 16 so that the trunk side is filled with refrigerant gas. The refrigerant is heated by heat recovery of the waste water.
More specifically, the refrigerant exchanges heat with the waste water outside the pipe, and the waste water heats the refrigerant liquid so that the refrigerant is dried at the outlet of the evaporator 16 and sucked into the compressor 18. is there.

As the compressor 18, for example, a capacity-controlled reciprocating compressor or a rotary or centrifugal compressor is used. Particularly, in the case of a reciprocating compressor, the lubricant is returned to a low pressure chamber such as a crank chamber, and in the case of a screw compressor, the lubricant is returned to a low pressure region or an intermediate pressure region of the compressor casing. The drive motor 38 of the compressor 18 in the refrigerant circuit 12 is provided with an inverter device 40 so that the rotational speed of the drive motor 38 can be controlled.
In this case, as described later, instead of measuring the oil temperature in the compressor 18, the temperature of the refrigerant return pipe 26, which is the refrigerant suction pipe upstream of the compressor 18, is measured, and this refrigerant suction pipe temperature is used. Thus, the opening degree of the electronic expansion valve 24 is adjusted, which is advantageous for a scroll type compressor having no oil sump inside, for example.

An oil separator 42 is provided on the downstream side of the compressor 18, and the lubricant separated by the oil separator 42 is returned to the compressor 18. A condenser 22 and a liquid receiver 44 are sequentially provided on the downstream side of the oil separator 42, and an electromagnetic valve (opening / closing the refrigerant circuit 12 at the start or stop of operation) is provided on the downstream side of the liquid receiver 44. (Not shown) and an expansion valve 24 are provided. The condenser 22 may be an evaporation type, a water cooling type, or an air cooling type. The refrigerant return pipe 26 upstream of the compressor 18 is provided with a temperature sensor (not shown) for detecting the refrigerant gas temperature and a pressure sensor (not shown) for detecting the refrigerant gas pressure.
A conventionally known superheat degree controller 25 is attached to the electronic expansion valve 24, and the superheat degree set value in which the detected superheat degree detected during operation is adjusted by the superheat degree set value adjusting means 100 as will be described later. The superheat degree controller 25 adjusts the opening degree of the electronic expansion valve 24 by, for example, PID control so as to be (target superheat degree).

As shown in FIG. 2, the superheat setting value adjusting means 100 includes a heat source fluid inlet temperature detecting means 102 that detects the inlet temperature of the heat source fluid in the evaporator 16, and a refrigerant gas that detects the outlet temperature of the refrigerant gas in the evaporator. The temperature difference between the inlet temperature of the heat source fluid detected by the outlet temperature detection means 104, the heat source fluid inlet temperature detection means 102, and the outlet temperature of the refrigerant gas in the evaporator 16 detected by the refrigerant gas outlet temperature detection means 104 is calculated. The temperature difference setting means 106 to be set, the refrigerant suction pipe temperature detection means 108 for detecting the temperature of the refrigerant suction pipe, and the condensation prevention for setting a temperature margin necessary for preventing condensation of the refrigerant gas flowing out from the evaporator 16 From the temperature of the refrigerant suction pipe detected by the temperature margin setting means 110 and the refrigerant suction pipe temperature detection means 108, a condensation prevention temperature margin is obtained. By reducing the condensation prevention temperature margin set by the fixing means 110, the safe evaporation temperature calculating means 112 for calculating the safe evaporation temperature of the refrigerant, and the inlet temperature of the heat source fluid detected by the heat source fluid inlet temperature detecting means 108, And a superheat degree set value calculating means 114 for calculating a superheat degree set value by subtracting the temperature difference set by the safe evaporation temperature calculated by the safe evaporation temperature calculating means 112 and the temperature difference setting means.
The heat source fluid inlet temperature detection means 108 is preferably installed at a position where the temperature in the vicinity of the compressor 18 is most unlikely to rise.
Furthermore, it has the superheat degree set value transmission means 116 which transmits the superheat degree set value calculated by the superheat degree set value calculation means 114 to the superheat degree controller 25 of the electronic expansion valve.
Furthermore, it has a standard superheat degree set value setting means 118 for setting a standard superheat degree set value, and when the superheat degree set value reaches the standard superheat degree set value, the superheat degree set value by the superheat degree set value adjusting means 100 is set. The superheat degree set value adjustment release means 120 for releasing the adjustment is provided.
As shown in FIG. 2, the release signal from the superheat degree set value adjustment release means 120 may be transmitted directly to the superheat degree controller 25 or may be sent to the superheat degree set value transmission means 116.

In the evaporator 16, the refrigerant liquid is vaporized by heat exchange with the heat source fluid, and is sucked into the compressor 18 through the refrigerant return pipe 26. At this time, from the viewpoint of preventing liquid compression, the degree of superheat (detection of the operating state) is detected. (Superheat degree) is adjusted to the target superheat degree. Hereinafter, adjustment of the degree of superheat of the refrigerant circuit 12 will be described.
As shown in FIG. 3, the refrigerant pressure PL and the refrigerant temperature T1 on the suction side of the compressor 18 are detected, PL is converted into a saturated steam temperature T2, and the superheat degree SH is calculated by T1-T2, and this superheat degree is calculated. The electronic expansion valve 24 is controlled so that becomes the target superheat degree SH.
More specifically, the superheat degree SH is obtained by the following formula.
Superheat degree SH = (refrigerant outlet refrigerant gas temperature T1) − (refrigerant evaporation pressure equivalent saturation temperature T2)
In the formula, the refrigerant outlet refrigerant gas temperature T1 of the refrigerant is detected by a temperature sensor. The saturation temperature T2 corresponding to the evaporation pressure of the refrigerant in the evaporator 16 is converted by the controller from the evaporation pressure PL of the refrigerant detected by the pressure sensor, and the equation is calculated by the controller to obtain the superheat degree SH of the refrigerant.

When the operation is started, the refrigerant starts to circulate in the refrigerant circuit 12 in the circuit, and the opening degree of the electronic expansion valve 24 is set to 0% in this state. Next, an operation amount in the opening direction of the expansion valve 24 is calculated by the controller. The operation of the expansion valve 24 is, for example, PID controlled by a controller. The target value of the refrigerant SH is set to SV = 6 ° C., for example.

The expansion valve 24 is operated by the PID control in the range of MV = 0 to 100% by the controller so that the selected operation amount is obtained.
The above is the case where the electronic expansion valve 24 operates in the positive direction of operation (opening direction), but the same control is performed even when the expansion valve 24 operates in the negative direction of operation (closed direction).
In the controller, an electric signal is transmitted to the expansion valve 24 in order to adjust the opening degree of the electronic expansion valve 24. In this case, for example, an electric signal of 0 to 20 mA is linearly associated with a superheat degree of 0 to 30K.

The operation of the control apparatus for the refrigeration apparatus having the above configuration will be described with reference to FIG.
As shown in FIG. 4, when the heat source side temperature gradient curve decreases from the evaporator inlet temperature toward the evaporator outlet temperature, the refrigerant side temperature gradient curve increases from the evaporator inlet temperature toward the evaporator outlet temperature. In addition, the difference between the heat source side evaporator inlet temperature A and the refrigerant side evaporator outlet temperature is set as the reference approach B, and from the viewpoint of preventing liquid back to the compressor, the condensation prevention temperature with respect to the suction pipe temperature C A difference E (temperature margin) is set, whereby the safe evaporation temperature D is calculated as D = CE.
Next, the superheat setting value F is calculated by the following calculation formula (a).
F = A-D-B = A- (CE) -B (a)

Based on the equation (a), the superheat degree set value F is calculated, and the superheat degree set value F is transmitted to the superheat degree controller 25 so that the detected superheat degree becomes the superheat degree set value F.

In this case, in equation (a), based on the heat source side evaporator inlet temperature A and the suction pipe temperature C measured during the cooling operation, using the set reference approach B and the condensation prevention temperature difference E, the degree of superheat Since the set value F is calculated, the condensation prevention temperature difference E is ensured by controlling the detected superheat degree to be the superheat degree set value F.
The superheat degree set value F calculated based on the equation (a) is transmitted to the superheat degree controller 25, and the degree of opening of the electronic expansion valve is set so that the detected superheat degree becomes the superheat degree set value F in the superheat degree controller 25. Adjust.
In particular, when the refrigeration apparatus is started, if the detected superheat degree is controlled to be the superheat degree set value F,
For example, even if the suction pipe temperature C is low in winter, the safe evaporation temperature D is set lower than the suction pipe temperature C by the condensation prevention temperature difference E. Therefore, the liquid back to the compressor is obtained by recondensing the refrigerant. Can be prevented.
The set values of the reference approach B and the condensation prevention temperature difference E may be set, for example, based on the test operation result of the refrigeration apparatus.
In particular, the larger the anti-condensation temperature difference E is, that is, the larger the superheat setting value F is, the more reliably the liquid back to the compressor can be prevented, but the flow rate of the refrigerant is reduced. Refrigeration capacity of the refrigeration apparatus increases because the refrigerant flow rate increases as the anti-condensation temperature difference E decreases, that is, as the superheat setting value F decreases. However, since the risk of liquid back to the compressor increases, the determination may be made in consideration of prevention of liquid back to the compressor and the refrigerating capacity of the refrigeration apparatus.

FIG. 5 is a diagram illustrating an example of a temporal change in the superheat degree set value controlled by the control device of the refrigeration apparatus.
As shown in FIG. 5, for example, the refrigerant intake pipe temperature is low immediately after the start of operation as in the operation of the refrigeration apparatus in winter, and gradually increases with the lapse of time as the operation continues, and becomes substantially constant after time T1. On the contrary, the superheat setting value is large immediately after the start of the refrigeration apparatus, gradually decreases with time, and is substantially constant after time T1.
After time T1, as shown by the equation (a), the superheat setting value is maintained constant as long as the heat source side evaporator inlet temperature A is constant. In this case, the standard superheat setting value setting is set. A standard superheat degree set value is set in advance by means 118, and when the superheat degree set value reaches the standard superheat degree set value, superheat by the superheat degree set value adjustment means 100 is overheated by the superheat degree set value adjustment release means 120. The adjustment of the degree setting value may be canceled.
At that time, the standard superheat degree set value may be determined by trial and error by trial operation, for example, and may be set to the superheat degree set value at time T1.
Further, as a modification, when the rising slope of the rising curve of the refrigerant suction pipe temperature becomes gentle with time, the condensation prevention temperature difference E (temperature margin) is set according to the reduction of the rising slope of the refrigerant suction pipe temperature. You may make it reduce gradually.
As a result, in the operation up to time T1, liquid back prevention to the compressor is achieved, and the condensation prevention temperature difference E (temperature margin) is gradually reduced, thereby making the condensation prevention temperature difference E (temperature margin) constant. Compared with the case where it does, it is also possible to accelerate | stimulate reduction of a superheat degree setting value and to utilize the freezing capacity of a freezing apparatus effectively.

According to the control device of the refrigeration apparatus 10 having the above-described configuration, when the refrigeration apparatus 10 is started, the superheat degree setting value adjusting unit 100 causes the evaporation temperature of the refrigerant in the evaporator 16 to be the temperature of the refrigerant suction pipe to the compressor 18. By adjusting the superheat setting value for the electronic expansion valve 24 so as to be lower, the evaporating temperature of the refrigerant is in this way even in the winter, even when the temperature of the refrigerant suction pipe is low due to cooling by the outside air. It is possible to prevent the liquid back to the compressor 18 due to recondensation of the refrigerant without the need to heat the refrigerant suction pipe separately at the time of starting so that the temperature of the refrigerant suction pipe becomes lower. As the refrigerant suction pipe is gradually heated as the operation of the refrigeration apparatus 10 is continued, the refrigeration apparatus is configured to reduce the superheat degree setting value by the superheat degree setting value adjusting means 100. 0 it is possible to operate with the appropriate efficiency.

The embodiments of the present invention have been described in detail above, but various modifications or changes can be made by those skilled in the art without departing from the scope of the present invention.
For example, in the present embodiment, the control device or the control method for the heat pump heat recovery device has been described. However, the present invention is not limited to this, and during cold start, for example, start in winter, the evaporation temperature of the refrigerant is the ambient temperature. Applicable to higher refrigeration facilities in general.
Further, for example, in the present embodiment, the case where the superheat setting value is adjusted when the refrigerant suction pipe temperature fluctuates has been described. However, the present invention is not limited to this, and the refrigerant suction pipe temperature is substantially constant. It is also applicable when the heat source side evaporator inlet temperature fluctuates.

1 is an overall configuration diagram of a refrigeration apparatus according to an embodiment of the present invention. It is a block diagram of the control part of the superheat degree of the freezing apparatus which concerns on embodiment of this invention. It is the schematic of the part which concerns on the detection of the superheat degree of the freezing apparatus which concerns on embodiment of this invention. It is a temperature gradient curve figure which shows the concept of control of the superheat degree of the freezing apparatus which concerns on embodiment of this invention. It is a figure which shows an example of the time change of the superheat degree setting value controlled by the control apparatus of the freezing apparatus which concerns on embodiment of this invention.

DESCRIPTION OF SYMBOLS 10 Refrigeration apparatus 12 Refrigerant circuit 16 Evaporator 18 Compressor 20 Refrigerant outbound pipe 22 Condenser 24 Electronic expansion valve 26 Refrigerant return pipe 38 Driving motor 40 Inverter apparatus 42 Oil separator 44 Liquid receiver 47 Accumulator 52 Control part 100 Superheat degree Set value adjusting means 102 Heat source fluid inlet temperature detecting means 104 Refrigerant gas outlet temperature detecting means 106 Temperature difference setting means 108 Refrigerant intake pipe temperature detecting means 110 Condensation prevention temperature margin setting means 112 Safe evaporation temperature calculating means 114 Superheat setting value calculating means 116 Superheat setting value transmitting means 118 Standard superheat setting value setting means 120 Superheat setting value adjustment canceling means

Claims (10)

A compressor, a condenser, an electronic expansion valve whose opening degree is adjusted so that the detected superheat degree becomes a superheat degree set value, and an evaporator are connected in this order, and a refrigerant circuit in which the refrigerant circulates is provided. In the control device for the refrigeration apparatus, a refrigerant suction pipe temperature detecting means for detecting an outer wall temperature of the refrigerant suction pipe to the compressor is provided in the vicinity of the upstream side of the compressor, and when the refrigeration apparatus is started, The degree of superheat is set so that the evaporation temperature of the refrigerant in the evaporator is lower than the temperature of the refrigerant suction pipe, and is set according to the degree of heating of the refrigerant suction pipe by the refrigerant gas detected by the refrigerant suction pipe temperature detecting means A control device for a refrigeration apparatus, comprising: a superheat degree set value adjusting means for adjusting a superheat degree set value for the electronic expansion valve that reduces the degree of superheat . The superheat degree set value adjusting means includes heat source fluid inlet temperature detecting means for detecting the inlet temperature of the heat source fluid in the evaporator,
Refrigerant gas outlet temperature detection means for detecting the outlet temperature of the refrigerant gas in the evaporator;
A temperature difference setting means for setting a temperature difference between the inlet temperature of the heat source fluid detected by the heat source fluid inlet temperature detector and the outlet temperature of the refrigerant gas in the evaporator detected by the refrigerant gas outlet temperature detector;
Anti-condensation temperature margin setting means for setting a temperature margin necessary to prevent condensation of the refrigerant gas flowing out of the evaporator;
Safe evaporation temperature calculation for calculating the safe evaporation temperature of the refrigerant by subtracting the condensation prevention temperature margin set by the condensation prevention temperature margin setting means from the temperature of the refrigerant suction pipe detected by the refrigerant suction pipe temperature detection means Means,
By subtracting the safe evaporation temperature calculated by the safe evaporation temperature calculation means and the temperature difference set by the temperature difference setting means from the inlet temperature of the heat source fluid detected by the heat source fluid inlet temperature detection means, the degree of superheat The control device for a refrigeration apparatus according to claim 1, further comprising a superheat degree set value calculation means for calculating a set value. Furthermore, the control apparatus of the refrigerating apparatus of Claim 2 which has a superheat degree setting value transmission means which transmits the superheat degree setting value calculated by the said superheat degree setting value calculation means to the superheat degree controller of the said electronic expansion valve. Furthermore, it has a standard superheat degree set value setting means for setting a standard superheat degree set value, and when the superheat degree set value reaches the standard superheat degree set value, the superheat degree set value by the superheat degree set value adjusting means The control device for a refrigeration apparatus according to claim 2 or 3, further comprising a superheat degree set value adjustment release means for releasing the adjustment. The refrigeration apparatus heats water supplied from the outside to the condenser by condensation latent heat of the refrigerant in the condenser to supply steam / high-temperature water, and exhaust heat supplied from the outside to the evaporator as a heat source The control device for a refrigeration apparatus according to any one of claims 1 to 4, which is a heat pump heat recovery device configured to evaporate a refrigerant in the evaporator. The control device for a refrigerating apparatus according to claim 1, wherein the compressor is a scroll type having no oil sump inside. A refrigeration apparatus comprising the control device for a refrigeration apparatus according to any one of claims 1 to 6. A compressor, a condenser, an electronic expansion valve whose opening degree is adjusted so that the detected superheat degree becomes a superheat degree set value, and an evaporator are connected in this order, and a refrigerant circuit in which the refrigerant circulates is provided. In the control method of the freezing device,
Setting a temperature difference between the inlet temperature of the heat source fluid and the outlet temperature of the refrigerant gas in the evaporator, and setting a temperature margin necessary to prevent condensation of the refrigerant gas flowing out of the evaporator;
Detecting the inlet temperature of the heat source fluid in the evaporator and the outlet temperature of the refrigerant gas, and detecting the temperature of the refrigerant suction pipe to the compressor;
Calculating a safe evaporation temperature of the refrigerant by subtracting the set condensation prevention temperature margin from the detected temperature of the refrigerant suction pipe; and
Calculating a superheat setting value by subtracting the calculated safe evaporation temperature and the set temperature difference from the detected inlet temperature of the heat source fluid; and
Thereby, when starting the refrigeration system, the superheat degree setting value for the electronic expansion valve is adjusted so that the evaporation temperature of the refrigerant in the evaporator is lower than the temperature of the refrigerant suction pipe to the compressor. Control method of refrigeration equipment. The method of controlling a refrigeration apparatus according to claim 8, wherein the adjustment step of the superheat degree set value includes a step of gradually reducing the superheat degree set value in accordance with an increase in the refrigerant suction pipe temperature. The method of controlling a refrigeration apparatus according to claim 8, wherein the temperature margin setting step includes a step of gradually reducing the temperature margin in accordance with a decrease in the rising slope of the refrigerant suction pipe temperature.

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