JPS60164820A - Control circuit of heat exchanger for cooling - Google Patents

Abstract

PURPOSE:To prevent freezing and boiling of a cooling medium and to perform a stable and sure cooling operation by switching one freezer to the start state and the stop state in accordance with variance of temperature of a region to be cooled. CONSTITUTION:When a freezer 17 or/and a freezer 18 are operated and the temperature of gas in a region 11 to be cooled is not varied, outputs of two comparing circuits in a control circuit 22 are logical ''0'' together, and a stop signal S and a start signal K are not generated, and a stable cooling operation is performed. If the temperature of gas in the region 11 is lowered when two freezers are operated, outputs of comparing circuits are logical ''1'', and the signal S is generated to stop operation of the freezer 18, and the freezing force of a cooler 14 is weakened. If the temperature of gas in the region 11 is raised when only the freezer 17 is operated, outputs of comparing circuits are logical ''1'', and the signal K is generated to start the freezer 18, and the freezing force of the cooler 14 is strengthened.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cooling heat exchange device, and particularly to a control circuit for controlling a refrigerator for cooling a refrigerant.

As is well known, a cooling heat exchange device has conventionally been constructed as shown in FIG. That is, the area to be cooled 11
The atmosphere inside (hereinafter referred to as gas) is supplied to a cooling heat exchanger (hereinafter referred to as cooler) 14 via a duct 13 by the action of a blower 12 . At this time, the gas is cooled by exchanging heat with the refrigerant within the cooler 14. Then, this cooled gas is returned to the region to be cooled 11 via the duct 13, thereby cooling the region to be cooled 11.

On the other hand, the refrigerant heated to a high temperature by exchanging heat with the gas is divided and guided to a plurality of (two in the illustrated case) refrigerators 17 and 18 via piping 16 by the action of the circulation pump 15. The refrigerant is then cooled by the refrigerator '17, J8, and guided to the cooler 14 again via the pipe 16.
This is used for cooling the above gas.

However, in the conventional cooling heat exchange device as described above, for example, if the temperature of the gas in the cooled area 11 decreases due to the influence of disturbance etc., relatively speaking, the temperature of the gas in the cooled area 11 decreases.
Since the refrigerating capacity is increased compared to No. 1, the temperature of the refrigerant drops too much and the refrigerant freezes, causing problems such as damage to the cooling heat exchange device or loss of its cooling function. Conversely, two refrigerators 17.
If one of the refrigerators 18 is stopped and only one refrigerator 17 or 18 continues to operate, and the temperature □ of the gas in the region to be cooled 11 rises, the temperature in the region to be cooled 11 increases. This means that the refrigerating capacity of the single operating refrigerator 17 or 18 is insufficient to suppress the temperature rise of the refrigerant, and the refrigerant reaches its boiling point, resulting in a cooling failure. This may cause problems such as damage to the heat exchange equipment used or loss of its cooling function.

This invention has been made in consideration of the above circumstances, and is an extremely good cooling heat exchanger that prevents the refrigerating capacity from becoming insufficient due to temperature fluctuations in the area to be cooled, and always performs stable and reliable cooling operation. The purpose is to provide a control circuit for the device.

That is, the control circuit of the cooling heat exchange device according to the present invention includes a refrigerant circulation path in which the refrigerant flowing out from the cooling heat exchanger is divided into a plurality of refrigerators to be cooled and then flows into the cooling heat exchanger. A cooling heat exchange device having a measuring means for measuring the temperature and flow rate of the refrigerant flowing into and out of the cooling heat exchanger, and a measuring means for measuring the temperature and flow rate of the refrigerant flowing into and out of the cooling heat exchanger, refrigeration capacity calculation means for calculating the refrigeration capacity for the refrigerating capacity; refrigeration capacity lower limit calculation means for calculating the lower limit of the refrigeration capacity based on the output data from the measurement means and the first refrigerant temperature setting value; □ Refrigerating capacity upper limit calculating means for calculating the above-mentioned refrigeration capacity upper limit based on the output data from the measuring means and the second refrigerant film production constant value; MAT control means for selectively controlling the plurality of refrigerators to start and stop states by comparing the output data from the capacity limit and upper limit calculation means, respectively. □ Hereinafter, an example m1 of the present invention will be explained in detail with reference to the drawings. Only the different parts will be explained here. That is, in the piping 16 on the side into which the refrigerant of the cooler 14 is introduced, there is a cooler 14'.
Temperature detector 1 for detecting the temperature gate of the refrigerant flowing into the
Further, in the piping 1θ on the side from which the refrigerant of the cooler 14 is discharged, a temperature detector 20 is provided for detecting the temperature of the refrigerant discharged from the cooler 14.
is provided. Further, in the piping 16, between the temperature detector 20 and the circulation pump 15, there is a flow rate of the refrigerant before being divided to the two refrigerators 17 and 18, that is, the flow rate of the refrigerant passing through the cooler 14. A flow rate detector 2j is provided to detect the flow rate of the refrigerant. 'And', the temperature sensor 19, 20 and the flow rate sensor 2
Each temperature data θe output from 1.

θa and flow rate data wFi, respectively control circuit 22
is supplied to. Although the details will be described later, this control circuit 22 sends an excitation signal K or a stop signal to the chiller freezer 8 according to the temperature change of the region to be cooled 11 based on the above-mentioned data θe, θa, and W. Presented in outputting S: Freezing-1
8 is activated or stopped to change the freezing ability of the cooler 14 for the region 11 to be cooled.
There are five things to do. □ Here, before explaining the detailed configuration of the control circuit 22, I would like to explain the basic operation of the M system i-plane road. That is, the refrigerating capacity of the cooler 14 for the area to be cooled 11 Qc il:% Qe=θBCw−θecw (1) However, C
is the specific heat and its unit is [K''/].

Further, the units of temperature data θa and θe are C°C], the units of flow rate data W are (''/)tc, and the units of 1-ha refrigerating capacity Qe are ('/)min.

becomes. Here, a case will be considered in which the temperature of the gas in the region to be cooled 11 decreases while the two refrigerators 17.11j are both operating. First, the temperature of the refrigerant is 17.18
The temperature is the lowest between when it flows out from the cooler 14 and when it flows into the cooler 14, so in short, unless the temperature data θe of the refrigerant flowing into the cooler 14 becomes lower than the freezing temperature θf of the refrigerant, freezing of the refrigerant can be prevented. It is something that can be done.

Therefore, the above equation (1) is applied to the temperature data θe, and in order for the refrigerant not to freeze, it is sufficient that the above-mentioned conditions are satisfied. In other words, regarding the refrigerating capacity Qc, from the above formula, Qc < (θa−θf)
Cw - (3), and if the refrigerating capacity Qe is smaller than the value determined by the right side of the above equation (3) (hereinafter referred to as the lower limit calculation value of the refrigerating capacity), the refrigerant will not freeze.

Next, consider a case where the temperature of the gas in the region to be cooled 11 increases while only the refrigerator 17 is operated and the refrigerator 18 is stopped. Then, since the temperature of the refrigerant is highest between when it flows out from the cooler 14 and when it flows into the refrigerator 17, in short, unless the temperature data θa of the refrigerant flowing out from the cooler 14 exceeds the boiling point temperature θb of the refrigerant, It can prevent boiling of the refrigerant.

Therefore, when the above equation (1) is solved for the temperature data θa, it becomes: In order for the refrigerant not to boil, the following conditions need to be satisfied, as described above. In other words, regarding the refrigerating capacity Qc, from the above equation, Qe < (θ
b-θe ) Cw -010, (5), and if the refrigerating capacity Qc is smaller than the value determined by the right side of the above equation (5) (hereinafter referred to as the calculated upper limit of the refrigerating capacity), the refrigerant will not boil.

Therefore, the control circuit 22 calculates the above equation (3) and (
5) Perform the calculation shown in equation (3), and when equation (3) is no longer satisfied, generate a stop signal S to the refrigerator 18, and perform the calculation shown in equation (5).
) is no longer satisfied, the refrigerator 18 is threatened with a start signal K.

FIG. 3 shows details of the control circuit 22.

That is, 23, 24, and 25 in the figure are input terminals to which the above-mentioned temperature data θa, θe and flow rate data W are respectively supplied, and 26 in the figure calculates the refrigerating capacity Qe shown by the above equation (1). It is a refrigerating capacity calculation circuit, and subtracts temperature data θa and θe by a subtraction unit 26a,
The subtraction result (θa −ee) is multiplied by the multiplier 26b, and the specific heat C is added to the flow rate data W using the potentiometer 27.
By multiplying the value Cw multiplied by (θa−
011) CW The refrigerating capacity Qe is calculated.

Further, 28 in the figure is a refrigerating capacity lower limit calculation circuit that calculates the refrigerating capacity lower limit calculation value, and the subtracting unit 28a subtracts the freezing temperature θf preset in the setting unit 28b from the temperature data θa, and the subtraction result is By multiplying (θa-θf) by the output value Cw of the potentiometer 27 by the multiplier 28c, (θa-θf)Cw
is calculated.

Further, numeral 29 in the figure is a refrigerating capacity upper limit calculation circuit that calculates the refrigerating capacity upper limit calculation value, and the subtracting unit 29a subtracts the temperature data θe from the boiling point temperature θb preset in the setting unit 29b, and the subtraction result is (θb−θe)
(θb−θe)CW is calculated by fully multiplying the output value Cw of the potentiometer 27 by the multiplier 29c.

Here, the refrigerating capacity Qc calculated as described above and the lower and upper limit calculated values of the refrigerating capacity are as follows. '
31, respectively. Of these, the comparison circuit 30 compares the refrigerating capacity Qc and the lower limit calculation value of the refrigerating capacity (θa−θ
When f) Cw satisfies the relationship of equation (3) above, a logical value at Ou is output, and when the relationship is no longer satisfied, a logical value tL III is output. Further, the comparison circuit 31 compares the refrigeration capacity Qc and the refrigeration capacity upper limit calculation value (θ
When b−θe)Cw satisfies the relationship of equation (5) above, a logical value Pa0'' is output, and when the relationship is no longer satisfied, a logical value It 1 ## is output.

The output of the comparison circuit 30 is supplied to the stop signal generation circuit 32 and also supplied to one input terminal of the AND circuit 34 via the NOT circuit 33. This stop signal generation circuit 32 generates a stop signal S when the logical value "1" is supplied, and outputs the stop signal S to the refrigerator 18 via an output terminal 35.
This is what is output to. Further, the output of the AND circuit 34 is supplied to one input terminal of an OR circuit 36. on the other hand,
The output of the comparison circuit 31 is supplied to the other input terminal of the OR circuit 36.

The output of the OR circuit 36 is supplied to the activation signal generation circuit 37 and also to the other input terminal of the AND circuit 34. This starting signal generation circuit 37 generates a starting signal K when the logical value "1#" is supplied, and outputs it to the refrigerator 18 via an output terminal 38.

For this reason, first, if two refrigerators 77, 78 or one refrigerator 17 are operated and there is no temperature fluctuation in the gas in the region to be cooled 1 due to disturbance etc., the above-mentioned (3)
Since the relationship between equations and θ(5) are both satisfied, the outputs of comparator circuits 3.0 and 31 both have a logic value of "0", and both the stop signal S and the start signal have an i output. In addition, when the refrigerators 17 and 18 are both operating, the temperature of the gas in the region 11 to be cooled decreases, and the relationship in equation (3) above is satisfied. Suppose you are no longer satisfied. Then, the output of the comparison □ circuit 30 becomes the logical value "'1", so a stop signal i is generated, the operation of the refrigerator 18 is stopped, and the refrigerating capacity of the i cooler 14 is weakened. Therefore, it is possible to prevent the refrigerant from freezing.

Furthermore, assume that the temperature of the gas in the region to be cooled 11 increases while only one refrigerator 17 is being operated, and the relationship in equation (5) is no longer satisfied. Then, since the output of the comparison circuit 31 becomes the logical value u1at, a start signal K is generated, the refrigerator 18 is started, and the refrigerating capacity of the cooler 14 is strengthened. Therefore, it is possible to prevent the refrigerant from boiling.

Therefore, according to the configuration of the above embodiment, one of the refrigerators 18 is switched between the start state and the stop state according to temperature fluctuations in the cooled area '11, thereby preventing freezing and boiling of the refrigerant. This makes it possible to perform stable and reliable cooling operations. Further, the values θf and θb set in the setting units 28b and 29b can be set with a margin higher and lower than the actual freezing temperature and boiling point temperature of the refrigerant, respectively, for even more effective results. This is the result.

Therefore, as described in detail above, according to the present invention, there is provided a refrigerant circulation path that cools the refrigerant flowing out from the cooling heat exchanger by dividing it into a plurality of refrigerators, and causes the refrigerant to flow into the cooling heat exchanger. The cooling heat exchange device includes a measuring means for measuring the temperature and flow rate of the refrigerant flowing into and out of the cooling heat exchanger, and a measuring means for measuring the temperature and flow rate of the refrigerant flowing into and out of the cooling heat exchanger, and a measuring means for measuring the temperature and flow rate of the refrigerant flowing into and out of the cooling heat exchanger, and a measuring means for measuring the temperature and flow rate of the refrigerant flowing into and out of the cooling heat exchanger, and measuring means for measuring the temperature and flow rate of the refrigerant flowing into and out of the cooling heat exchanger, and measuring means for measuring the temperature and flow rate of the refrigerant flowing into and out of the cooling heat exchanger. refrigeration capacity calculation means for calculating the refrigeration capacity of the refrigeration capacity, refrigeration capacity lower limit calculation means for calculating the lower limit of the refrigeration capacity based on the output data from the measurement means and the first refrigerant temperature setting value, refrigeration capacity upper limit calculation means for calculating the upper limit of the refrigeration capacity based on output data and a second refrigerant temperature setting value; and output data of the refrigeration capacity calculation means and each output data from the refrigeration capacity lower limit and upper limit calculation means. and a control means for selectively controlling the plurality of refrigerators to a starting state and a stopping state by comparing the above, respectively, so that it is possible to prevent additions or deficiencies in the refrigeration capacity due to temperature fluctuations in the cooled area. However, it is possible to provide an extremely good control circuit for a cooling heat exchange device that can always perform stable and reliable cooling operations.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a conventional cooling heat exchange device, FIG. 2 is a block diagram showing an embodiment of the control circuit of the cooling heat exchange device according to the present invention, and FIG. 3 is the same embodiment. FIG. 11... Area to be cooled, 12... Blower, 13 River duct, 14... Cooler, 15... Circulation pump, 16
...Piping, 17. J, 9°... Refrigerator, 19.20.
...Temperature detector, 21...Flow rate detector, 22...Control circuit, 23-25...Input terminal, 26...Refrigerating capacity calculation circuit, 27...Potentiometer, 2B01.
Refrigeration capacity lower limit calculation circuit, 29... Refrigeration capacity upper limit calculation circuit, 30.31... Comparison circuit, 32... Stop signal generation circuit, 33... Knot circuit, 34... AND circuit, 35. ...Output terminal, 36...OR circuit, 37...
- Start signal generation circuit, 38...output terminal.

Claims (1)

[Claims] In a cooling heat exchange device having a refrigerant circulation path in which the refrigerant flowing out from the cooling heat exchanger is divided into a plurality of refrigerators for cooling and flowing into the cooling heat exchanger, the cooling heat exchanger is cooled. a measuring means for measuring the temperature and flow rate of the refrigerant flowing into and out of the refrigerant; a refrigerating capacity calculating means for calculating the refrigerating capacity for the area to be cooled based on output data from the measuring means; refrigeration capacity lower limit calculation means for calculating the lower limit of the refrigeration capacity based on the output data from the means and the first refrigerant temperature setting value; A refrigeration capacity upper limit calculation means for calculating an upper limit of refrigeration capacity;
control means for selectively controlling the plurality of refrigerators to start and stop states by comparing the output data of the refrigeration capacity calculation means and each output data from the refrigeration capacity lower limit and upper limit calculation means, respectively; A control circuit for a cooling heat exchange device characterized by: