KR102615320B1 - PCM Air Dryer - Google Patents

Abstract

A PCM air dryer according to an embodiment of the present invention is an air chiller in which compressed air and refrigerant are introduced, the refrigerant vaporizes, lowers the temperature of the compressed air, and discharges the cooled air. It is connected to the air chiller, and the refrigerant A screw refrigerator that compresses, sets the pressure dew point, and controls the capacity so that the pressure dew point is kept constant, a condenser that is water-cooled and liquefies the refrigerant compressed by the screw refrigerator, is connected to the condenser, and has a PCM inside. It is provided and includes a PCM storage that lowers the condensing pressure of the condenser and an expansion valve that expands the refrigerant liquefied by the condenser, and the PCM storage is where coolant is input, and the temperature of the input coolant is lower than the phase change temperature of the PCM. If it is high, the PCM changes phase, and the temperature of the coolant can be lowered by the latent heat generated during the phase change.

Description

PCM Air Dryer {PCM Air Dryer}

The present invention relates to a PCM air dryer, and more specifically, to a PCM air dryer that saves energy by lowering condensing pressure using PCM and allows precise stepless capacity control using a screw refrigerator.

Compressed air is used throughout industrial facilities. If compressed air is used without the moisture contained in it being removed, breakdowns and problems with various devices may occur, so it is common to use an air dryer to dehumidify compressed air. Conventional air dryers have to be continuously operated for dehumidification even when compressed air is not used, resulting in the problem of unnecessary energy being wasted.

Korean Patent No. 10-1945843 discloses an air dryer that can be operated only when necessary in conjunction with a fluctuating load to solve the problem of energy wastage. However, reducing power consumption through freezer ON/OFF control is fatal to the lifespan of the freezer, causes large dew point fluctuations, uses a lot of electricity, and cannot use screw refrigeration compressors applied to large capacity, making precise stepless capacity control impossible.

Therefore, research is required on PCM air dryers that save energy by lowering condensation pressure using PCM (Phase Change Material) and enable precise stepless capacity control using screw refrigerators.

Korean Patent No. 10-1945843

The purpose of the present invention is to provide a PCM air dryer in which PCM storage is provided to lower the temperature of the cooling water, thereby lowering the refrigerant condensation pressure and thus lowering the compression ratio, thereby reducing the power consumption of the refrigerator.

In addition, another object of the present invention is that by providing a screw refrigerator, the effect of reducing refrigerator power consumption can be maximized when the amount of compressed air used is low, in winter and in spring and fall when temperatures are not high, and by setting the pressure dew point and maintaining uniformity. The purpose is to provide a PCM air dryer capable of precise capacity control to create a refrigeration system that can be maintained efficiently.

In addition, another object of the present invention is to save energy by recovering waste heat (waste cold water) by cooling the PCM by supplying cold condensate of 4°C to 10°C discharged from the water separator by the PCM water chiller. It provides PCM air dryer.

In addition, another object of the present invention is to provide a PCM air dryer that is provided with a solenoid valve to control the supply of refrigerant to the PCM water chiller, thereby preventing unnecessary energy consumption.

A PCM air dryer according to an embodiment of the present invention is an air chiller in which compressed air and refrigerant are introduced, the refrigerant vaporizes, lowers the temperature of the compressed air, and discharges the cooled air. It is connected to the air chiller, and the refrigerant A screw refrigerator that compresses, sets the pressure dew point, and controls the capacity so that the pressure dew point is kept constant, a condenser that is water-cooled and liquefies the refrigerant compressed by the screw refrigerator, is connected to the condenser, and has a PCM inside. It is provided and includes a PCM storage that lowers the condensing pressure of the condenser and an expansion valve that expands the refrigerant liquefied by the condenser, and the PCM storage is where coolant is input, and the temperature of the input coolant is lower than the phase change temperature of the PCM. If it is high, the PCM changes phase, and the temperature of the coolant can be lowered by the latent heat generated during the phase change.

In addition, the PCM air dryer according to an embodiment of the present invention is connected to the air chiller, and includes a moisture separator that separates the moisture contained in the discharged cold air into condensate and discharges the cold, dry air from which the moisture has been removed. More may be included.

In addition, the PCM air dryer according to an embodiment of the present invention is connected to the PCM storage and a moisture separator, and includes a PCM water chiller that cools the PCM by receiving condensate of 4°C to 10°C from the moisture separator. More may be included.

In addition, the PCM air dryer according to an embodiment of the present invention has a temperature sensor provided in the PCM storage outlet pipe to measure the temperature of the coolant discharged from the PCM storage, and a temperature sensor installed in the PCM water chiller inlet pipe connected to the condenser. It may further include a PCM water chiller expansion valve and a solenoid valve provided on one side of the PCM water chiller expansion valve, which determines whether to block the supply of refrigerant according to the measured value of the temperature sensor.

In addition, the solenoid valve according to an embodiment of the present invention supplies refrigerant to the PCM water chiller through the PCM water chiller expansion valve when the measured value exceeds the phase change temperature of the PCM, and the measured value is When the phase change temperature of the PCM is reached, the refrigerant supply to the PCM water chiller expansion valve may be blocked.

In addition, the PCM air dryer according to an embodiment of the present invention, when the average error (A _err ) of the temperature sensor calculated by the following [Equation 1] is greater than the preset limit error (S _err ), the temperature It may further include a sensor monitoring unit that determines that the sensor is broken.

[Equation 1]

(Here, A _err is the average error, T _aver is the overall average of the measured values measured by the temperature sensor, P _aver is the partial average of n measured values measured by the temperature sensor, and T _σ is the average of the measured values measured by the temperature sensor. refers to the overall standard deviation of one measurement value)

The PCM air dryer according to an embodiment of the present invention has the effect of lowering the temperature of the cooling water by providing PCM storage, thereby lowering the refrigerant condensation pressure and thus lowering the compression ratio, thereby reducing power consumption of the refrigerator.

In addition, the PCM air dryer according to an embodiment of the present invention is equipped with a screw refrigerator, so that the refrigerator power consumption reduction effect can be maximized when the amount of compressed air used is low and in winter and spring and fall seasons when temperatures are not high. It has the effect of enabling precise capacity control to create a refrigeration system that can set and maintain the pressure dew point uniformly.

In addition, in the PCM air dryer according to an embodiment of the present invention, the PCM water chiller receives cold condensate of 4°C to 10°C discharged from the moisture separator to cool the PCM, thereby recovering waste heat (waste cold water). It has the effect of saving energy.

In addition, the PCM air dryer according to an embodiment of the present invention is provided with a solenoid valve to control the supply of refrigerant to the PCM water chiller, thereby preventing unnecessary energy consumption.

1 is a block diagram showing a PCM air dryer according to an embodiment of the present invention.
Figure 2 is a block diagram showing a PCM air dryer according to another embodiment of the present invention.
Figure 3 is a circuit diagram showing a PCM air dryer according to an embodiment of the present invention.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings. However, the idea of the present invention is not limited to the presented embodiments, and those skilled in the art who understand the idea of the present invention can add, change, or delete other components within the scope of the same idea, thereby creating other degenerative inventions or the present invention. Other embodiments that are included within the scope of the invention can be easily proposed, but this will also be said to be included within the scope of the invention of the present application.

Hereinafter, the PCM air dryer 100 of the present invention will be described in detail with reference to the attached FIGS. 1 to 3.

Figure 1 is a block diagram showing a PCM air dryer according to an embodiment of the present invention, Figure 2 is a block diagram showing a PCM air dryer according to another embodiment of the present invention, and Figure 3 is an embodiment of the present invention. This is a circuit diagram showing a PCM air dryer according to an example.

Referring to FIG. 1, the PCM air dryer 100 according to an embodiment of the present invention includes an air chiller 110, a screw refrigerator 120, a condenser 130, a PCM storage 140, and an expansion valve 150. It can be included.

Compressed air and refrigerant are introduced into the air chiller 110, and the refrigerant vaporizes, lowering the temperature of the compressed air and discharging the cooled air.

The screw refrigerator 120 is connected to the air chiller 110, compresses the refrigerant, sets a pressure dew point, and can control capacity to keep the pressure dew point constant. By providing the screw refrigerator 120, the effect of reducing refrigerator power consumption can be maximized when the amount of compressed air used is low, in winter and in spring and fall when temperatures are not high, and the pressure dew point can be set and maintained uniformly. It can have the effect of enabling precise capacity control so that it can be used as a refrigeration system.

The condenser 130 is water-cooled and can liquefy the refrigerant compressed by the screw refrigerator 120.

The PCM storage 140 is connected to the condenser 130, and a PCM (Phase Change Material) is provided therein to lower the condensation pressure of the condenser 130. The PCM storage 140 is configured to change the phase of the PCM when coolant is introduced and the temperature of the coolant is higher than the phase change temperature of the PCM, and the water temperature of the coolant is changed using latent heat generated during the phase change. It can be lowered. The phase change temperature of the PCM can be set to 30°C to 40°C. As the PCM storage 140 lowers the temperature of the coolant, the refrigerant condensation pressure (high pressure) decreases, and the compression ratio (the ratio between high and low pressure) decreases accordingly, thereby reducing power consumption of the refrigerator. For reference, since the power consumption of a refrigeration compressor is precisely proportional to the high pressure of the refrigerant (condensing pressure, high pressure), it is important to keep the condensing pressure low in order to save energy in the dryer.

The expansion valve 150 can expand the refrigerant liquefied by the condenser 130.

Referring to Figure 2, the PCM air dryer 100 according to an embodiment of the present invention includes a moisture separator 115, a PCM water chiller 160, a temperature sensor 170, a PCM water chiller expansion valve 180, and a solenoid. It may further include a valve 190.

The moisture separator 115 is connected to the air chiller 110, separates the moisture contained in the discharged cold air into condensate, and discharges the cold, dry air from which the moisture has been removed.

The PCM water chiller 160 is connected to the PCM storage 140 and the moisture separator 115, and can cool the PCM by receiving condensed water from the moisture separator 115. The PCM water chiller 160 receives condensed water discharged from the water separator 115 and cools the PCM, thereby recovering waste heat (waste cold water) and saving energy.

The temperature sensor 170 is provided in the outlet pipe of the PCM storage 140 and can measure the temperature of the coolant discharged from the PCM storage 140.

The PCM water chiller expansion valve 180 may be provided in the inlet pipe of the PCM water chiller 160 connected to the condenser 130.

The solenoid valve 190 is provided on one side of the PCM water chiller expansion valve 180, and can determine whether to block the supply of refrigerant according to the measured value of the temperature sensor 170. The solenoid valve 190 supplies refrigerant to the PCM water chiller 160 through the PCM water chiller expansion valve 180 when the measured value exceeds the phase change temperature of the PCM, and the measured value When the phase change temperature of the PCM is reached, provision may be made to block the supply of refrigerant to the PCM water chiller expansion valve 180. By controlling the supply of refrigerant through the solenoid valve 190, unnecessary energy consumption can be prevented.

In addition, the PCM air dryer 100 according to an embodiment of the present invention has an average error (A _err ) of the temperature sensor 170 calculated by the following [Equation 1] than the preset limit error (S _err ). In large cases, it may further include a sensor monitoring unit (not shown) that determines that the temperature sensor 170 is broken.

If the average error (A _err ) of the temperature sensor 170 is greater than the preset limit error (S _err ), the sensor monitoring unit may determine that the temperature sensor 170 is broken.

[Equation 1]

(Here, A _err is the average error, T _aver is the overall average of the measured values measured by the temperature sensor 170, P _aver is the partial average of n measured values measured by the temperature sensor 170, T _σ means the overall standard deviation of the measured value measured by the temperature sensor 170)

More specifically, T _aver is the overall average of the measured values measured by the temperature sensor 170, and is sensed by collecting a large number of data during a preset period (ex. one month) during which the temperature sensor 170 operates normally. It means a value calculated by calculating the overall average of the measured values, and T _σ means a value calculated by calculating the overall standard deviation of the measured values sensed by collecting a large number of data during the preset period (ex. one month).

In addition, P _aver is a partial average of n measured values of the temperature sensor 170, and in the process of installing and using the temperature sensor 170 in the field, a preset number (n) of measured values are input in real time and the above It calculates the average of a preset number (n) of measured values, and can be referred to as a partial average because it corresponds to the average of some measured values.

At this time, if the estimated average value is calculated with 95% confidence using partial averages, the estimated average value (μ) is It has a range.

Therefore, the average error (A _err ), which is the difference between the upper or lower limit of the estimated average value (μ) and the overall average (T _aver ), can be calculated as in [Equation 1] above.

Therefore, the fact that the average error (A _err ) calculated by [Equation 1] is greater than the preset limit error (S _err ) means that the preset number (n) of measured values received in real time are measured by the temperature sensor 170. Since it means that there is a very high possibility that the temperature sensor 170 is incorrectly input due to a malfunction, the sensor monitoring unit (not shown) can determine that the temperature sensor 170 is broken when the above conditions are met.

Meanwhile, the sensor monitoring unit compares the average value (A _err ) calculated by [Equation 1] and the preset limit value (S _err ) to determine whether there is an error in the measured value, and at the same time, the temperature sensor 170 By measuring the temperature, whether the measured temperature is outside the preset range, whether the real-time measured value shows a pattern that is periodically repeated within the preset section size, and measuring the humidity around the temperature sensor 170 When the measured humidity is outside the preset range, the ratio of the operating time and non-operating time of the sensor is analyzed to determine whether the ratio is outside the preset ratio range, and at least one of the above conditions is satisfied. It may be determined that an error has occurred in the measured value.

Hereinafter, the specific details of the above error determination methods will be described in detail.

First, in order to measure the temperature of the temperature sensor 170 and determine whether the measured temperature is outside the preset range, a separate monitoring temperature sensor is provided within a preset distance from the temperature sensor 170, and the monitoring The temperature of the temperature sensor 170 can be monitored in real time through the temperature sensor. This uses the technical principle of maintaining the heat generation temperature within an allowable range (preset heat generation temperature range) when the temperature sensor 170 is operating normally. If the heat generation is excessive or there is no heat generation at all, it is overloaded. Since it can be assumed that the temperature sensor 170 is not operating at all, in that case it can be determined that an error has occurred in the temperature sensor 170, which can be inferred that an error has occurred in the real-time measured value.

Next, in order to determine whether there is an error in the measured value, it is possible to monitor whether the measured value shows a pattern that is periodically repeated within a preset section size, which is when foreign matter enters the temperature sensor 170. , it uses the technical principle that measurement values can be repeatedly output in a specific pattern within a preset section size due to incoming foreign substances. At this time, the preset section size can be determined according to [Equation 2] below.

[Equation 2]

A _range = {(T _aver + D _max ) - (T _aver - D _max )}*0.3

A _range is the preset section size, T _aver is the overall average during the preset period, and D _max means the maximum deviation during the preset period.

For example, if the overall average during the preset period is 70 and the maximum deviation is 20, the A _range is 12, so periodically repeating values are output in the range where the difference between the maximum and minimum values does not exceed 12 (ex. 52, 62 , 52, 62, 53, 62, 52, 63, etc. are repeatedly output, it can be assumed that foreign matter has entered the temperature sensor 170 and an error has occurred in the measured value.

Next, in order to measure the humidity of the temperature sensor 170 and determine whether the measured humidity exceeds a preset value, a humidity sensor is separately provided within a preset distance from the temperature sensor 170, and the humidity sensor is Through this, the humidity of the temperature sensor 170 can be monitored in real time. This uses the technical principle that if moisture flows into the temperature sensor 170, it operates abnormally. If the humidity exceeds a preset value, it can be assumed that moisture has flowed into the temperature sensor 170. Therefore, in this case, it can be determined that an error has occurred in the temperature sensor 170, which can be inferred to have resulted in an error in the measured value.

Finally, by analyzing the ratio of the operating time and non-operating time of the temperature sensor 170, it is possible to determine whether the ratio is outside the preset ratio range, and based on the results, it is determined that an error has occurred in the measured value. You can judge.

For example, if the temperature sensor 170 installed in the field is set to collect measured values by 0.1 seconds every second to save power, the ratio of operating time to non-operating time is 10:1, but analysis is performed through real-time monitoring. As a result, if the ratio is reversed to 1:10 or changes to a significantly different ratio (ex. ratio change of 30% or more), it can be determined that the temperature sensor 170 is malfunctioning and an error has occurred in the measured value.

As described above, in one embodiment of the present invention, the sensor monitoring unit can determine whether there is an error in the measured value by considering all the multiple fault diagnosis methods, and all the multiple fault diagnosis methods are as shown in [Equation 3] below. The final judgment may be made based on the reflected S _total value.

[Equation 3]

S _total = W1*R _aver + W2*R _tem + W3*R _rep + W4*R _hum + W5*R _rat

Here, S _total is the sum of multiple error judgment values, and R _aver is _the error judgment value ( _error A value between 0 and 1 depending on whether the temperature is outside the preset range), R _tem is a value that determines whether there is an error depending on whether the temperature is outside the preset range (a value between 0 and 1 depending on whether there is an error), R _rep is a value that determines whether there is an error depending on whether a repeating pattern appears (a value between 0 and 1 depending on whether there is an error), and R _hum is a value that determines whether there is an error depending on whether the humidity is outside the preset range (error either 0 or 1 depending on whether R _rat is the value determined for error by analyzing the ratio of operating time and non-operating time (either 0 or 1 depending on whether there is an error), W1 is the R _aver item weight, W2 is the R _tem item weight, and W3 is R. _Rep item weight, W4 means R _hum item weight, and W5 means R _rat item weight, respectively.

For example, if S _total is more than 4, it can be preset to indicate that there is an error in the measured value. If the heating temperature is a very important parameter, W2 can be preset to 3, and W1, W3, W4, and W5 are all set to 1. Can be preset.

Under these conditions, as a result of monitoring errors according to the above multiple fault diagnosis methods, if R _aver is 1, R _tem is 1, R _rep is 0, R _hum is 0, and R _rat is 0, then S _total is 4. Therefore, it can be finally determined that there is an error in the measured value.

As seen above, according to an embodiment of the present invention, PCM storage is provided to lower the water temperature of the cooling water, thereby lowering the refrigerant condensation pressure, thereby lowering the compression ratio, thereby reducing the power consumption of the refrigerator, and screw By providing a refrigerator, the effect of reducing refrigerator power consumption can be maximized when compressed air usage is low, in winter and in spring and fall when temperatures are not high, and a refrigeration system can be created that can set and maintain the pressure dew point uniformly. It has the effect of enabling precise capacity control.

In addition, in the PCM air dryer according to an embodiment of the present invention, the PCM water chiller receives cold condensate of 4°C to 10°C discharged from the moisture separator to cool the PCM, thereby recovering waste heat (waste cold water). Energy can be saved, and a solenoid valve is provided to control the supply of refrigerant, thereby preventing unnecessary energy consumption.

As described above, although one embodiment of the present invention has been described with limited examples and drawings, one embodiment of the present invention is not limited to the above-described embodiment, which is based on common knowledge in the field to which the present invention pertains. Anyone who has the knowledge can make various modifications and variations from this description. Accordingly, an embodiment of the present invention should be understood only by the scope of the claims set forth below, and all equivalent or equivalent modifications thereof shall fall within the scope of the spirit of the present invention.

100: PCM air dryer
110: Air chiller
115: Moisture separator
120: Screw freezer
130: condenser
140: PCM storage
150: Expansion valve
160: PCM water chiller
170: Temperature sensor
180: PCM water chiller expansion valve
190: Solenoid valve

Claims (5)

An air chiller (110) into which compressed air and refrigerant are introduced, the refrigerant vaporizes, lowers the temperature of the compressed air, and discharges the cooled air;
A screw refrigerator 120 connected to the air chiller 110, compressing the refrigerant, setting a pressure dew point, and controlling capacity to keep the pressure dew point constant;
A condenser 130 that is water-cooled and liquefies the refrigerant compressed by the screw refrigerator 120;
A PCM storage 140 connected to the condenser 130 and provided with a PCM (Phase Change Material) therein to lower the condensing pressure of the condenser 130; and
An expansion valve 150 that expands the refrigerant liquefied by the condenser 130;
Including,
The PCM storage 140 is,
When coolant is introduced, and the temperature of the introduced coolant is higher than the phase change temperature of the PCM, the PCM undergoes a phase change, and the latent heat generated during the phase change lowers the water temperature of the coolant,
A moisture separator (115) connected to the air chiller (110), separates moisture contained in the discharged cold air into condensate, and discharges cold, dry air from which the moisture has been removed;
A PCM water chiller (160) connected to the PCM storage (140) and the moisture separator (115) and cooling the PCM by receiving condensate of 4°C to 10°C from the moisture separator (115);
A temperature sensor 170 provided in the outlet pipe of the PCM storage 140 to measure the temperature of the coolant discharged from the PCM storage 140;
A PCM water chiller expansion valve (180) provided in the inlet pipe of the PCM water chiller (160) connected to the condenser (130); and
A solenoid valve 190 provided on one side of the PCM water chiller expansion valve 180 and determining whether to block the supply of refrigerant according to the measured value of the temperature sensor 170;
It further includes,
The solenoid valve 190 is,
If the measured value exceeds the phase change temperature of the PCM, refrigerant is supplied to the PCM water chiller (160) through the PCM water chiller expansion valve (180),
When the measured value reaches the phase change temperature of the PCM, the refrigerant supply to the PCM water chiller expansion valve 180 is blocked,
If the average error (A _err ) of the temperature sensor 170 calculated by the following [Equation 1] is greater than the preset limit error (S _err ), the sensor monitoring unit determines that the temperature sensor 170 is broken. (not shown);
A PCM air dryer further comprising:
[Equation 1]

(Here, A _err is the average error, T _aver is the overall average of the measured values measured by the temperature sensor 170, P _aver is the partial average of n measured values measured by the temperature sensor 170, T _σ means the overall standard deviation of the measured value measured by the temperature sensor 170) delete delete delete delete