Description:TECHNICAL FIELD
The present subject matter relates generally to field of cooling towers. Particularly, but not exclusively the disclosure relates to method and system for controlling a cooling tower in an industrial plant based on atmospheric conditions.
BACKGROUND
Cooling towers are one of the significant components along with many other heavy machineries in an industrial unit. Cooling towers are unit operations that are used in large numbers in different kind of industries. Typically, in a cooling tower operation, hot process water is pumped at top of cooling towers and sprayed by sparges. Air is blown in the cooling towers with help of draft fans which cool down water by evaporation. Cold water then flows in cold well and finally pumped back to process by cold pumps. This is a cyclic process, so over a period of operation, Total Dissolved Solids (TDS) of water tends to increase. Hence, periodic blowdown of water is performed in cooling towers to control the TDS of water in circulation.
Generally, performance of the cooling towers is a function of climatic conditions. Two prime parameters of climate i.e., humidity and ambient air temperature, control cooling efficiency and hence power consumption of the cooling towers. Typically, contribution of humidity is about 85 percentage more than ambient air temperature. This is because during evaporative cooling of water, there are two types of heat loss i.e., sensible heat loss and latent heat loss. Quantity of latent heat loss is about 85 percentage higher than sensible heat loss and humidity contributes to this latent heat loss by phase change. Thus, both humidity and ambient air temperature is used to calculate wet bulb temperature. The wet bulb temperature is defined as lowest temperature to which water can be cooled at given climatic conditions. During manufacturing of the cooling towers, design is mostly based on calculating approach of cooling tower. Ideally, wet bulb temperature should be equal to cooling tower outlet water temperature. But this is impractical as it would require infinite long column making it a highly energy intensive system. So, optimal range of approach for any cooling tower design is kept between (7-8) ?. Initial selection of the cooling towers with respect to design wet bulb temperature is always made based on climatic conditions existing at tower site. That is, the wet temperature selected is generally close to the average maximum ambient air temperature for summer months and humidity average maximum for monsoon months. Thus, throughout a year, the cooling towers currently run at full designed capacities which is not required as wet bulb temperature fluctuate drastically over different seasons. Hence, there is a need to reduce energy consumption of cooling towers.
Further, since the wet bulb temperature varies with seasons so does the range of cooling tower. Range of cooling tower is mathematically denoted as difference between inlet and outlet temperature of cooling tower water. Range is indicative of overall cooling tower performance. Optimal range for any cooling tower is (7-8) ?, but due to fixed design conditions, the range exceeds beyond (11-12) ? during operations in some seasons signifying unnecessary wastage of power. However, in actual, calculated power consumption of a cooling tower at a given climatic condition is significantly less than actual power consumption.
The information disclosed in this background of the disclosure section is only for enhancement of understanding of the general background of the disclosure and should not be taken as an acknowledgement or any form of suggestion that this information forms prior art already known to a person skilled in the art.
SUMMARY
One or more shortcomings of the prior art may be overcome, and additional advantages may be provided through the present disclosure. Additional features and advantages may be realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed disclosure.

In a non-limiting embodiment of the disclosure, a method of controlling a cooling tower in an industrial plant based on atmospheric conditions is disclosed. The method includes receiving, by a control system communicatively connected with a cooling tower system of a cooling tower, values of a plurality of parameters of the cooling tower from a plurality of sensors placed at predetermined locations in the cooling tower. The method includes determining a value of a wet bulb temperature (T2) associated with the cooling tower based on the values of the plurality of parameters. Further, the method includes validating a plurality of predefined conditions of each of one or more hot pumps and cooling tower fans associated with the cooling tower based on the value of the wet bulb temperature, the values of the plurality of parameters and threshold set points. Thereafter, the method includes determining a control value for each variable frequency drive associated with respective one or more hot pumps and cooling tower fans based on the validation, for controlling the cooling tower.
In an embodiment of the disclosure, the plurality of parameters of the cooling tower comprises dry bulb temperature (T1), Relative Humidity (RH), cooling tower outlet temperature (T3), cold well temperature (T4), cooling tower inlet temperature (T5), Total Dissolved Solids (TDS) value, Blow Down Valve (BDV).

In an embodiment of the disclosure, the value of the wet bulb temperature (T2) is determined based on dry bulb temperature (T1) and Relative Humidity (RH).

In an embodiment of the disclosure, the plurality of sensors comprises dry bulb temperature sensor (T1), cooling tower outlet temperature sensor (T3), a cold well temperature sensor (T4), a hot well temperature sensor (T5), a TDS sensor (TDS), a relative humidity sensor (RH).

In an embodiment of the disclosure, the dry bulb temperature sensor (T1) is placed in a climatic site at which the cooling tower is located for measuring ambient air temperature.

In an embodiment of the disclosure, the cooling tower outlet temperature sensor (T3) is located at cooling tower outlet line to measure cooled water temperature and the cold well temperature sensor (T4) is located at a cold well of the cooling tower.

In an embodiment of the disclosure, the hot well temperature sensor (T5) is placed at a header of a cooling tower inlet line to measure hot water temperature and the TDS sensor (TDS) is placed in a hot water inlet line to measure total dissolved solids of cooling tower inlet water, and the relative humidity sensor (RH) is placed along with the dry bulb temperature sensor (T1).

In an embodiment of the disclosure, the control value corresponds to a value of speed for the one or more hot pumps and cooling tower fans.

In an embodiment of the disclosure, the speed for the one or more hot pumps is increased when difference between value of cooling tower inlet temperature and cold well temperature (T5-T4) is greater than threshold differential temperature between hot well and cold well temperature, or when difference between value of the cold well temperature and cooling tower outlet temperature (T4-T3) is greater than threshold differential temperature between cold well and CT outlet temperature.

In an embodiment of the disclosure, the speed for the one or more hot pumps is decreased when value of cooling tower inlet temperature and cold well temperature (T5-T4) is less than threshold differential temperature between hot well and cold well temperature.

In an embodiment of the disclosure, the speed of the one or more hot pumps is maximum when a value of relative humidity is less than a minimum threshold relative humidity value.

In an embodiment of the disclosure, the speed of the one or more cooling fans is increased when difference between a value of cooling tower outlet temperature and a wet bulb temperature (T3-T2) is greater than a target value.

In an embodiment of the disclosure, the speed of the one or more cooling fans is deceased when difference between a value of cooling tower outlet temperature and a wet bulb temperature (T3-T2) is less than a target value.

In one non-limiting embodiment of the disclosure, a control system for controlling a cooling tower in an industrial plant based on atmospheric conditions is disclosed. The control system comprises a processor and a memory communicatively coupled to the processor, where the memory stores processor executable instructions, which, on execution, may cause the control system to receive values of a plurality of parameters of the cooling tower from a plurality of sensors placed at predetermined locations in the cooling tower. The control system determines a value of a wet bulb temperature (T2) associated with the cooling tower based on the values of the plurality of parameters. Further, the control system validates a plurality of predefined conditions of each of one or more hot pumps and cooling tower fans associated with the cooling tower based on the value of the wet bulb temperature, the values of the plurality of parameters and threshold set points. Thereafter, the control system determines a control value for each variable frequency drive associated with respective one or more hot pumps and cooling tower fans based on the validation, for controlling the cooling tower.

The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

BRIEF DESCRIPTION OF THE ACCOMPANYING DIAGRAMS

The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate exemplary embodiments and, together with the description, serve to explain the disclosed principles. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system and/or methods in accordance with embodiments of the present subject matter are now described, by way of example only, and with reference to the accompanying figures, in which:

FIGURE.1A-1B show exemplary embodiments for controlling a cooling tower in an industrial plant based on atmospheric conditions in accordance with some embodiments of the present disclosure;

FIGURE.2 shows a detailed block diagram of a control system in accordance with some embodiments of the present disclosure;

FIGURES.3A-3C show flowcharts for controlling cooling fan, hot pumps and blow down valve, respectively in accordance with some embodiments of the present disclosure;

FIGURE.4 is a flowchart illustrating a method for controlling a cooling tower in an industrial plant based on atmospheric conditions in accordance with some embodiments of the present disclosure;

FIGURE.5A shows exemplary graphs for power comparison before and after implementation of control system in cooling towers of a wire rod mill, respectively in accordance with some embodiments of the present disclosure;
FIGURE.5B shows exemplary graph representing range of cooling tower of a wire rod mill in accordance with some embodiments of the present disclosure;
FIGURES 5C-5D show exemplary graphs representing percentage change in variable frequency drive frequency corresponding to energy savings in accordance with some embodiments of the present disclosure; and
FIGURE.6 is a block diagram of an exemplary computer system for implementing embodiments consistent with the present disclosure.
It should be appreciated by those skilled in the art that any block diagrams herein represent conceptual views of illustrative systems embodying the principles of the present subject matter. Similarly, it will be appreciated that any flow charts, flow diagrams, state transition diagrams, pseudo code, and the like represent various processes which may be substantially represented in computer readable medium and executed by a computer or processor, whether or not such computer or processor is explicitly shown.

DETAILED DESCRIPTION

In the present document, the word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment or implementation of the present subject matter described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.
While the disclosure is susceptible to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the drawings and will be described in detail below. It should be understood, however that it is not intended to limit the disclosure to the forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative falling within the scope of the disclosure.
The terms “comprises,” “comprising,” “includes” or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a setup, device, or method that includes a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup, device, or method. In other words, one or more elements in a system or apparatus proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or method.
Disclosed herein is a method and a system for controlling a cooling tower in an industrial plant based on atmospheric conditions. Generally, cooling towers run at full designed capacities throughout a year which is actually not required as wet bulb temperature (defined as lowest temperature to which water can be cooled at given climatic conditions) fluctuate drastically over different seasons. Currently, the design of cooling towers is fixed. Hence, though optimal range for any cooling tower is (7-8) ? but due to fixed design conditions, the range exceeds beyond (11-12) ? during operations in some seasons signifying unnecessary wastage of power.
Therefore, to solve the above problem, the present disclosure discloses a control system integrated with a cooling tower to control the cooling tower based on atmospheric conditions. Particularly, the control system controls one or more hot pumps and cooling tower fans of the cooling tower based on respective control value determined based on a plurality of validated predefined conditions corresponding to each of one or more hot pumps and cooling tower fans. The predefined conditions are validated based on values of a plurality of parameters which are obtained from a plurality of sensors placed at predetermined locations in the cooling tower. Thus, the present disclosure enables controlling the cooling tower based on atmospheric conditions and aids in reduction of power consumption in the cooling tower.

In the following detailed description of the embodiments of the disclosure, reference is made to the accompanying drawings that form a part hereof, and in which are shown by way of illustration specific embodiments in which the disclosure may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, and it is to be understood that other embodiments may be utilized and that changes may be made without departing from the scope of the present disclosure. The following description is, therefore, not to be taken in a limiting sense.

FIGURE.1A-1B show exemplary embodiments for controlling a cooling tower in an industrial plant based on atmospheric conditions in accordance with some embodiments of the present disclosure.

FIGURE.1A shows an exemplary cooling tower system 100 communicatively connected with a control system 101 for controlling the cooling tower based on atmospheric conditions. The cooling tower system 100 may be associated with any industrial plant. The control system 101 is show in Figure.1B. The control system 101 may include any computing device such as, a desktop computer, a laptop, a server, and the like. A person skilled in the art would understand that the scope of the present disclosure may encompass any other control system, not mentioned herein explicitly. The control system 101 includes an Input/ Output (I/O) interface 129, a processor 131 and a memory 130 for storing instructions executable by the processor 131. The I/O interface 129 is coupled with the processor 131 through which an input signal or/and an output signal is communicated. Further, the control system 101 may include a Human Machine Interface (HMI) display for displaying total current and power consumption of the cooling tower system 100 to operator of the control system 101.
Returning to Figure.1A, the cooling tower system 100 comprises a hot well 103, a cooling tower 105 and a cold well 107. The hot well 103 includes one or more hot pumps (121-123) and respective variable frequency drive (124-126) for controlling associated hot pump. While the cooling tower 105 includes cooling tower fans along with respective variable frequency drive (127-128) for controlling the associated cooling tower fan. Generally, hot water from a process such as, blast furnace may flow to hot well 103 from where the hot water is pumped to cooling tower 105. The hot water is sprayed in cooling tower 105 where the cooling tower fans operate at full rated speeds throughout a year to cool down the hot water by evaporation. The cool water then flows to cold well 107 and is pumped back to components associated with the process. This is a continuous cyclic operation where the one or more hot pumps (121-123) and cooling tower fans operate at designed speed throughout the year irrespective of any season.

Further, the cooling tower system 100 is configured with a plurality of sensors at predetermined locations. The plurality of sensors is connected with the control system 101 for performing the controlling of the cooling tower system 100. The plurality of sensors includes a dry bulb temperature sensor (T1) 109, a relative humidity sensor (RH) 111, a cooling tower outlet temperature sensor (T3) 113, a cold well temperature sensor (T4) 115, a hot well temperature sensor (T5) 117 and a TDS sensor (TDS) 119 along with a blow down valve 120. The dry bulb temperature (T1) 109 is placed in a climatic site at which the cooling tower system 100 is located for measuring ambient air temperature. The RH sensor 111 is placed in association with the T1 109. The T3 113 is located at cooling tower outlet line to measure cooled water temperature and the T4 115 is located at the cold well 107. The T5 117 is placed at a header of a cooling tower inlet line to measure hot water temperature and the TDS sensor 119 is placed in a hot water inlet line to measure total dissolved solids of cooling tower inlet water.

In such environment, the plurality of sensors (109-119) obtains and transmit values of a plurality of parameters of the cooling tower system 100 to the control system 101. In an embodiment, the values of the plurality of parameters may be in digital format. The plurality of parameters of the cooling tower system 100 comprises dry bulb temperature (T1), Relative Humidity (RH), cooling tower outlet temperature (T3), cold well temperature (T4), cooling tower inlet temperature (T5), Total Dissolved Solids (TDS) value and Blow Down Valve (BDV). The control system 101 determines a value of a wet bulb temperature (T2) associated with the cooling tower system 100 based on the values of the plurality of parameters. Particularly, the control system 101 may determine the value of the wet bulb temperature (T2) based on the dry bulb temperature (T1) and the Relative Humidity (RH). Further, the control system 101 may validate a plurality of predefined conditions of each of one or more hot pumps (121-123) and cooling tower fans associated with the cooling tower 105 based on the value of the determined wet bulb temperature, the values of the plurality of parameters and threshold set points. The plurality of predefined conditions is explained in subsequent figures of the present disclosure.

Thereafter, the control system 101 may determine a control value for each variable frequency drive (124-128) associated with respective one or more hot pumps (121-123) and cooling tower fans based on the validation. Particularly, the control value corresponds to a value of speed for the one or more hot pumps (121-123) and the cooling tower fans. For instance, the speed for the one or more hot pumps (121-123) is increased when difference between value of cooling tower inlet temperature and cold well temperature (T5-T4) is greater than threshold differential temperature between hot well and cold well temperature.

Alternatively, the speed for the one or more hot pumps (121-123) is increased when difference between value of the cold well temperature and cooling tower outlet temperature (T4-T3) is greater than threshold differential temperature between cold well and CT outlet temperature. On the other hand, the speed for the one or more hot pumps (121-123) is decreased when value of the cooling tower inlet temperature and the cold well temperature (T5-T4) is less than threshold differential temperature between hot well and cold well temperature. Further, the speed of the one or more hot pumps (121-123) is maximum when a value of relative humidity is less than a minimum threshold relative humidity value. Likewise, the speed of the one or more cooling fans is increased when difference between a value of cooling tower outlet temperature and a wet bulb temperature (T3-T2) is greater than a target value. While the speed of the one or more cooling fans is deceased when difference between a value of cooling tower outlet temperature and a wet bulb temperature (T3-T2) is less than a target value. Further, the
blow down valve 120 may be controller based on the value of TDS. For instance, if the value of TDS is more than threshold TDS, the blow down valve 120 is switched ON.

Thus, on receiving the control value from the control system 101 for each of the one or more hot pumps (121-123) and the cooling tower fans, the variable frequency drive (124-126) and variable frequency drive (127-128) may either increase or decrease the speed of one or more hot pumps (121-123) and the cooling tower fans, respectively.

A description of an embodiment with several components in communication with each other does not imply that all such components are required. On the contrary, a variety of optional components are described to illustrate the wide variety of possible embodiments of the invention.

FIGURE.2 shows a detailed block diagram of a control system in accordance with some embodiments of the present disclosure.

In some implementations, the control system 101 may include data 200 and modules 213. As an example, the data 200 is stored in the memory 130 associated with the control system 101. In some embodiments, the data 200 may include parameter data 201, wet temperature data 203, predefined condition data 205, control data 207 and other data 209. In some embodiments, the data 200 may be stored in the memory 130 in form of various data structures.

The parameter data 201 may include values of the plurality of parameters of the cooling tower system 100 received from the plurality of sensors. The plurality of parameters may include the dry bulb temperature (T1), the Relative Humidity (RH), the cooling tower outlet temperature (T3), the cold well temperature (T4), the cooling tower inlet temperature (T5), the Total Dissolved Solids (TDS) value and the Blow Down Valve (BDV).

The wet temperature data 203 includes the value of the wet bulb temperature (T2) associated with the cooling tower system 100 determined based on the values of the dry bulb temperature (T1) and the Relative Humidity (RH). The wet bulb temperature may vary accordingly during different atmospheric conditions.

The predefined condition data 205 may include one or more preset conditions for the one or more hot pumps (121-123) and the cooling tower fans. The one or more preset conditions may be a function of value of the wet bulb temperature, the values of the plurality of parameters and threshold set points associated with each of the plurality of parameters.

The control data 207 may include the control value determined for each variable frequency drive (124-128) associated with respective one or more hot pumps (121-123) and cooling tower fans.

The other data 209 may be stored data, including temporary data and temporary files, generated by the modules 213 for performing the various functions of the control system 101.

In an embodiment, the data 200 in the memory 130 are processed by the one or more modules 213 present within the memory 130 of the control system 101.

One or more modules 213 along with the data 200 functions to control a cooling tower in an industrial plant based on atmospheric conditions. In one implementation, the one or more modules 213 may include, but are not limited to, a communication module 215, a temperature determining module 217, a validation module 219, a control value determination module 221, and one or more other modules 223.

In an embodiment, the one or more modules 213 may be implemented as dedicated units. As used herein, the term module refers to an application specific integrated circuit (ASIC), an electronic circuit, a field-programmable gate arrays (FPGA), Programmable
(PSoC), a combinational logic circuit, and/or other suitable components that provide the described functionality. In some implementations, the one or more modules 213 may be communicatively coupled to the processor 131 for performing one or more functions of the control system 101. The said modules 213 when configured with the functionality defined in the present disclosure will result in a novel hardware.

The communication module 215 may receive the values of the plurality of parameters from the plurality of sensors (109-119). Further, the communication module 215 may transmit the control value to each of the variable frequency drive associated with the one or more hot pumps (121-123) and the cooling tower fans.
The temperature determining module 217 may determine the value of the wet bulb temperature (T2) associated with the cooling tower system 100 based on the values of the dry bulb temperature (T1) and the Relative Humidity (RH).

The validation module 219 may validate the plurality of predefined conditions of each of one or more hot pumps (121-123) and the cooling tower fans associated with the cooling tower system 100 based on the value of the wet bulb temperature, the values of the plurality of parameters and threshold set points. FIGURE.3A shows a flowchart for validating predefined conditions of cooling tower fans in accordance with some embodiments of the present disclosure. As shown in Figure.3A, at step 301, the values of the plurality of parameters are received from the plurality of sensors (109-119). At step 302, the value of the wet bulb temperature (T2) associated with the cooling tower system 100 is determined based on the values of the dry bulb temperature (T1) and the Relative Humidity (RH). At step 303, the cooling tower fans are initiated with maximum speed. At step 304, the validation module 219 may check if value of the Relative Humidity (RH) is greater than or equal to a maximum Relative Humidity (RH) (RHmax). In case of the value of the Relative Humidity (RH) is greater than or equal to the (RHmax), the speed of cooling tower fan is maximized as per step 303. Alternatively, at step 306, when the value of the Relative Humidity (RH) is not greater than or equal to the (RHmax), the validation module 219 check if difference between the value of cooling tower outlet temperature (T3) and the wet bulb temperature (T2) is equal to set target value. At step 307, difference between the value of cooling tower outlet temperature (T3) and the wet bulb temperature (T2) is equal to set target value, no change in speed of the cooling tower fan is identified. At step 308, when the difference between the value of cooling tower outlet temperature (T3) and the wet bulb temperature (T2) is not equal to set target value, the validation module checks if difference between the value of cooling tower outlet temperature (T3) and the wet bulb temperature (T2) is greater than set target value. At step 309, when difference between the value of cooling tower outlet temperature (T3) and the wet bulb temperature (T2) is greater than set target value, the validation module 219 determines to increase the speed of the cooling tower fans. While at step 310, when difference between the value of cooling tower outlet temperature (T3) and the wet bulb temperature (T2) is lesser than set target value, the validation module 219 determines to decrease speed of the cooling tower fans. In an embodiment, every change in the parameter may be maintained at a predefined time interval. In an embodiment, the speed of the cooling tower fans may be maintained at minimum set point (MSP).

FIGURE.3B shows a flowchart for validating predefined conditions of hot pumps in accordance with some embodiments of the present disclosure. As shown in Figure.3B, step 311 is same as step 301 and step 312 is same as step 302. At step 313, the hot pumps are initiated with maximum speed with ramp up time. At step 314, the validation module 219 may check if value of the Relative Humidity (RH) is less than a minimum Relative Humidity (RH) (RHmin). In case, the value of the Relative Humidity (RH) is less than the (RHmin), the speed of hot pumps is maximized as per step 313. Alternatively, at step 315, when the condition of step 314 is false, the validation module 219 may check if the value of Relative Humidity (RH) is within the range of RHmin and RHmax. If the condition of step 315 is true, condition of step 316a is evaluated. However, if the condition of step 315 is false, a condition defined in step 316b is evaluated. At step 316a, the validation module 219 may check if difference between the value of the cold well temperature and cooling tower outlet temperature (T4-T3) is greater than threshold differential temperature between cold well and CT outlet temperature (TDoff). At step 317, when the condition of step 316a is false, the validation module 219 may check difference between value of cooling tower inlet temperature and cold well temperature (T5-T4) is equal to threshold differential temperature between hot well and cold well temperature (TD). However, at step 318, when the condition of step 316a is true, the validation module 219 evaluates to increase speed of the hot pumps. At step 319, when the condition of step 317 is true, the validation module 219 evaluates no change in the speed of the hot pumps. Alternatively, at step 320, when the condition of step 317 is false, the validation module 219 checks if difference between value of (T5-T4) is greater than threshold differential temperature between hot well and cold well temperature (TD). If the condition of step 320 is true, the validation performs condition of step 318. While if the condition of step 320 is true, the validation module 219 at step 321 may evaluate to decrease the speed of the hot pumps.
At step 316b, the validation module 219 checks if the value of Relative Humidity (RH) is greater than or equal to RHmax. If the condition of step 316b is false, the condition of step 315 is re-evaluated. However, at step 322, when the condition of step 315b is true, the validation module 219 may check if the cold well temperature (T4) is equal to set point of cold well temperature (Tcw) required for plant operation. At step 323, when condition of step 322 is true, the validation module 219 may check if difference between value of (T5-T4) is equal to threshold differential temperature between hot well and cold well temperature (TD). At step 324, when the condition of step 323 is true, the validation module 219 determines no change in the speed of the hot pumps. However, at step 325, when the condition of step 322 is false, the validation module 219 may check if the cold well temperature (T4) is greater than Tcw. If the condition of step 325 is true, the validation module 219 performs the condition of step 318. On the other hand, at step 326, when the conditions of steps 323 and 325 are false, the validation module 219 may check difference between the value of cooling tower inlet temperature and cold well temperature (T5-T4) is greater than threshold differential temperature between hot well and cold well temperature (TD). If the condition of step 326 is true, the validation module 219 performs step 318. While if the condition of step 326 is false, the validation module 219 performs step 321. In an embodiment, the speed of the one or more hot pumps (121-123) may be maintained at minimum set point (MSP).

Similarly, FIGURE.3C shows a flowchart for validating predefined conditions of blow down valve in accordance with some embodiments of the present disclosure. As shown in Figure.3C, step 327 is same as step 311. At step 328, the validation module 219 may check if the threshold differential temperature between hot well and cold well temperature (TD) is greater than maximum permissible TDS (TDSmax). At step 329, when the condition of step 328 is false, the blow down valve is switched off. Alternatively, at step 330, when the condition of step 328 is true, the blow down valve is switched on. In an embodiment, for every iteration, the validation module 219 may check frequency change is 1 Hz and change of each of the parameter is maintained at a predefined time interval (DTime).

Returning to Figure.2, the control value determination module 221 may determine the control value for each of the variable frequency drive (124-126) of the one or more hot pumps (121-123) based on the validation as shown in Figure.3B. Further, the control value determination module 221 may determine the control value for each of the variable frequency drive (127-127) of the cooling tower fans based on the validation as shown in Figure.3A. The control value may correspond to a value of the speed for the one or more hot pumps (121-123) and cooling tower fans.

FIGURE.4 is a flowchart illustrating a method for controlling a cooling tower in an industrial plant based on atmospheric conditions in accordance with some embodiments of the present disclosure.

As illustrated in FIGURE.4, the method 400 comprises one or more blocks illustrating a method of controlling a cooling tower in an industrial plant based on atmospheric conditions in accordance with some embodiments of the present disclosure. The method 400 may be described in the general context of computer-executable instructions. Generally, computer-executable instructions can include routines, programs, objects, components, data structures, procedures, modules, and functions, which perform functions or implement abstract data types.

The order in which the method 400 is described is not intended to be construed as a limitation, and any number of the described method blocks can be combined in any order to implement the method 400. Additionally, individual blocks may be deleted from the methods without departing from scope of the subject matter described herein. Furthermore, the method 400 can be implemented in any suitable hardware, software, firmware, or combination thereof.

At block 401, the method 400 may include receiving, by the communication module 215, values of the plurality of parameters of the cooling tower from the plurality of sensors (109-119) placed at the predetermined locations in the cooling tower system 100. Thet plurality of parameters of the cooling tower comprises the dry bulb temperature (T1), the Relative Humidity (RH), the cooling tower outlet temperature (T3), the cold well temperature (T4), cooling tower inlet temperature (T5), the Total Dissolved Solids (TDS) value, the Blow Down Valve (BDV).

At block 403, the method 400 may include determining, by the temperature determining module 217, a value of the wet bulb temperature (T2) associated with the cooling tower based on the values of the plurality of parameters. Particularly, the value of the wet bulb temperature (T2) is determined based on the dry bulb temperature (T1) and the Relative Humidity (RH).

At block 405, the method 400 may include validating, by the validation module 219, the plurality of predefined conditions of each of one or more hot pumps (121-123) and the cooling tower fans associated with the cooling tower based on the value of the wet bulb temperature, the values of the plurality of parameters and threshold set points.

At block 405, the method 400 may include determining, by the control value determination module 221, the control value for each variable frequency drive (124-128) associated with respective one or more hot pumps (121-123) and the cooling tower fans based on the validation, for controlling the cooling tower. The control value corresponds to the value of the speed for the one or more hot pumps (121-123) and the cooling tower fans.

The present invention can be implemented for the cooling towers associated with different industrial plants. For instance, consider a wire rod mill, wherein the cooling tower system 100 associated with the wire rod mill is coupled with the control system 101. Further, the plurality of sensors (109-119) may be located at the predetermined locations of the cooling tower system 100. The values of the plurality of sensors (109-119) are transmitted to the control system 101 which may calculate the wet blub temperature based on current atmospheric condition and validate and compare one or more condition of hot pumps and cooling tower fans of the cooling tower system 100 of the wire rod mill and provides control value as output to respective variable frequency drives to control the speed of the hot pumps and the cooling tower fans. FIGURE.5A shows exemplary graphs for power comparison before and after implementation of control system in cooling tower of the wire rod mill, respectively in accordance with some embodiments of the present disclosure. As shown in first graph, before implementation of the present invention, the power consumption (of cooling tower fans and hot pumps) at full loads is 42.67 kW which reduced to 17.1 kW after the integration of the control system 101. This leads to a significant energy savings of approximately 60 percentage. This is evident from reduction in individual current of the hot pumps and cooling tower fans as shown in second graph. FIGURE.5B shows exemplary graph representing range of cooling tower of the wire rod mill in accordance with some embodiments of the present disclosure. As shown, the range of cooling tower i.e., difference between inlet and outlet temperatures is stabilised at a constant optimal value of around (7-8) ? after implementation of the control system 101 which was earlier at a higher side of (11-12) ? due to additional power intake which was not required. FIGURES 5C-5D show exemplary graphs representing percentage change in variable frequency drive frequency corresponding to energy savings in accordance with some embodiments of the present disclosure. Graphs shown in Figures 5C-5D represent a percentage change in frequency of the variable frequency drives corresponding to energy savings. As shown in Figure.5C, for 22 percentage change in speed of the hot pump, an energy savings of 44 percentage is achieved. While, for the cooling tower fans as shown in Figure.5D, 61 percentage change in speed lead to 83 percentage savings in energy. In an embodiment, considering a base value of 5 INR per kWh electricity, the electricity savings achieved in the wire rod mill is around 25.57 kWh. Further, due to reduction in the speed of the cooling tower fans, a reduction in drift and evaporation losses is achieved which in turn reduced requirement of water by 30 percentage. Further, in an embodiment, 1 kWh corresponds to an emission of 0.5 kg carbon dioxide. Hence, a savings of 25.57 kWh electricity by implementing the control system 101 may correspond to a reduction of 110 tons of carbon dioxide emissions annually.
FIGURE.6 is a block diagram of an exemplary computer system for implementing embodiments consistent with the present disclosure.
In some embodiments, FIGURE.6 illustrates a block diagram of an exemplary computer system 600 for implementing embodiments consistent with the present disclosure. In some embodiments, the computer system 600 can be the control system 101 that comprises a processor (also referred as a processor 602 in this FIGURE.6). The processor 602 may include at least one data processor for executing program components for executing user or system-generated business processes. The processor 602 may include specialized processing units such as integrated system (bus) controllers, memory management control units, floating point units, graphics processing units, digital signal processing units, etc.
The processor 602 may be disposed in communication with input devices 611 and output devices 612 via I/O interface 601. The I/O interface 601 may employ communication protocols/methods such as, without limitation, audio, analog, digital, stereo, IEEE-1394, serial bus, Universal Serial Bus (USB), infrared, PS/2, BNC, coaxial, component, composite, Digital Visual Interface (DVI), high-definition multimedia interface (HDMI), Radio Frequency (RF) antennas, S-Video, Video Graphics Array (VGA), IEEE 802.n /b/g/n/x, Bluetooth, cellular (e.g., Code-Division Multiple Access (CDMA), High-Speed Packet Access (HSPA+), Global System For Mobile Communications (GSM), Long-Term Evolution (LTE), WiMax, or the like), etc.
Using the I/O interface 601, computer system 600 may communicate with input devices 611 and output devices 612.
In some embodiments, the processor 602 may be disposed in communication with a communication network 609 via a network interface 603. The network interface 603 may communicate with the communication network 609. The network interface 603 may employ connection protocols including, without limitation, direct connect, Ethernet (e.g., twisted pair 10/100/1000 Base T), Transmission Control Protocol/Internet Protocol (TCP/IP), token ring, IEEE 802.11a/b/g/n/x, etc. Using the network interface 603 and the communication network 609, the computer system 600 may communicate with the plurality of sensors (109-119).
The communication network 609 can be implemented as one of the different types of networks, such as intranet or Local Area Network (LAN) and such within the organization. The communication network 609 may either be a dedicated network or a shared network, which represents an association of the different types of networks that use a variety of protocols, for example, Hypertext Transfer Protocol (HTTP), Transmission Control Protocol/Internet Protocol (TCP/IP), Wireless Application Protocol (WAP), etc., to communicate with each other.
Further, the communication network 609 may include a variety of network devices, including routers, bridges, servers, computing devices, storage devices, etc. In some embodiments, the processor 602 may be disposed in communication with a memory 605 (e.g., RAM, ROM, etc. not shown in FIGURE.6) via a storage interface 604. The storage interface 604 may connect to memory 605 including, without limitation, memory drives, removable disc drives, etc., employing connection protocols such as Serial Advanced Technology Attachment (SATA), Integrated Drive Electronics (IDE), IEEE-1394, Universal Serial Bus (USB), fibre channel, Small Computer Systems Interface (SCSI), etc. The memory drives may further include a drum, magnetic disc drive, magneto-optical drive, optical drive, Redundant Array of Independent Discs (RAID), solid-state memory devices, solid-state drives, etc.
The memory 605 may store a collection of program or database components, including, without limitation, a user interface 606, an operating system 607, a web browser 608 etc. In some embodiments, the computer system 600 may store user/application data, such as the data, variables, records, etc. as described in this invention. Such databases may be implemented as fault-tolerant, relational, scalable, secure databases such as Oracle or Sybase.
Operating system 607 may facilitate resource management and operation of computer system 600. Examples of operating systems include, without limitation, APPLE® MACINTOSH® OS X®, UNIX®, UNIX-like system distributions (E.G., BERKELEY SOFTWARE DISTRIBUTION® (BSD), FREEBSD®, NETBSD®, OPENBSD, etc.), LINUX® DISTRIBUTIONS (E.G., RED HAT®, UBUNTU®, KUBUNTU®, etc.), IBM®OS/2®, MICROSOFT® WINDOWS® (XP®, VISTA®/7/8, 10 etc.), APPLE® IOS®, GOOGLETM ANDROIDTM, BLACKBERRY® OS, or the like. User interface 606 may facilitate display, execution, interaction, manipulation, or operation of program components through textual or graphical facilities. For example, user interfaces may provide computer interaction interface elements on a display system operatively connected to computer system 600, such as cursors, icons, check boxes, menus, scrollers, windows, widgets, etc. Graphical User Interfaces (GUIs) may be employed, including, without limitation, Apple® Macintosh® operating systems’ Aqua®, IBM® OS/2®, Microsoft® Windows® (e.g., Aero, Metro, etc.), web interface libraries (e.g., ActiveX®, Java®, Javascript®, AJAX, HTML, Adobe® Flash®, etc.), or the like.
Computer system 600 may implement web browser 608 stored program components. Web browser 608 may be a hypertext viewing application, such as MICROSOFT® INTERNET EXPLORER®, GOOGLETM CHROMETM, MOZILLA® FIREFOX®, APPLE® SAFARI®, etc. Secure web browsing may be provided using Secure Hypertext Transport Protocol (HTTPS), Secure Sockets Layer (SSL), Transport Layer Security (TLS), etc. Web browsers 608 may utilize facilities such as AJAX, DHTML, ADOBE® FLASH®, JAVASCRIPT®, JAVA®, Application Programming Interfaces (APIs), etc. Computer system 600 may implement a mail server stored program component. The mail server may be an Internet mail server such as Microsoft Exchange, or the like. The mail server may utilize facilities such as ASP, ACTIVEX®, ANSI® C++/C#, MICROSOFT®,. NET, CGI SCRIPTS, JAVA®, JAVASCRIPT®, PERL®, PHP, PYTHON®, WEBOBJECTS®, etc. The mail server may utilize communication protocols such as Internet Message Access Protocol (IMAP), Messaging Application Programming Interface (MAPI), MICROSOFT® exchange, Post Office Protocol (POP), Simple Mail Transfer Protocol (SMTP), or the like. In some embodiments, the computer system 600 may implement a mail client stored program component. The mail client may be a mail viewing application, such as APPLE® MAIL, MICROSOFT® ENTOURAGE®, MICROSOFT® OUTLOOK®, MOZILLA® THUNDERBIRD®, etc.
Furthermore, one or more computer-readable storage media may be utilized in implementing embodiments consistent with the present invention. A computer-readable storage medium refers to any type of physical memory on which information or data readable by a processor may be stored. Thus, a computer-readable storage medium may store instructions for execution by one or more processors, including instructions for causing the processor(s) to perform steps or stages consistent with the embodiments described herein. The term “computer-readable medium” should be understood to include tangible items and exclude carrier waves and transient signals, i.e., non-transitory. Examples include Random Access Memory (RAM), Read-Only Memory (ROM), volatile memory, non-volatile memory, hard drives, Compact Disc (CD) ROMs, Digital Video Disc (DVDs), flash drives, disks, and any other known physical storage media.
An embodiment of the present disclosure enables controlling the cooling tower based on atmospheric conditions and aids in reduction of power consumption in the cooling tower.

An embodiment of the present disclosure helps in reduction of power consumption in cooling tower operation.

An embodiment of the present disclosure aids in reduction of water consumption and carbon dioxide.

Equivalents:
A description of an embodiment with several components in communication with each other does not imply that all such components are required. On the contrary a variety of optional components are described to illustrate the wide variety of possible embodiments of the invention. When a single device or article is described herein, it will be apparent that more than one device/article (whether or not they cooperate) may be used in place of a single device/article. Similarly, where more than one device or article is described herein (whether or not they cooperate), it will be apparent that a single device/article may be used in place of the more than one device or article, or a different number of devices/articles may be used instead of the shown number of devices or programs. The functionality and/or the features of a device may be alternatively embodied by one or more other devices which are not explicitly described as having such functionality/features. Thus, other embodiments of the invention need not include the device itself.

The specification has described a system and a method for determining and operating caster at an optimum casting speed in real-time. The illustrated steps are set out to explain the exemplary embodiments shown, and it should be anticipated that on-going technological development will change the manner in which particular functions are performed. These examples are presented herein for purposes of illustration, and not limitation. Further, the boundaries of the functional building blocks have been arbitrarily defined herein for the convenience of the description. Alternative boundaries can be defined so long as the specified functions and relationships thereof are appropriately performed. Alternatives (including equivalents, extensions, variations, deviations, etc., of those described herein) will be apparent to persons skilled in the relevant art(s) based on the teachings contained herein. Such alternatives fall within the scope and spirit of the disclosed embodiments. Also, the words "comprising," "having," "containing," and "including," and other similar forms are intended to be equivalent in meaning and be open-ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items or meant to be limited to only the listed item or items. It must also be noted that as used herein and in the appended claims, the singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise.
Finally, the language used in the specification has been principally selected for readability and instructional purposes, and it may not have been selected to delineate or circumscribe the inventive subject matter. It is therefore intended that the scope of the invention be limited not by this detailed description, but rather by any claims that issue on an application based here on. Accordingly, the embodiments of the present invention are intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the following claims.
Referral numerals
Reference Number Description
100 Cooling tower system
101 Control system
103 Hot well
105 Cooling tower
107 Cold well
109 Dry bulb temperature
111 Relative Humidity sensor (RH)
113 Cooling tower outlet temperature sensor (T3)
115 Cold well temperature sensor (T4)
117 Hot well temperature sensor (T5)
119 TDS sensor (TDS)
121-123 One or more hot pumps
124-126 Variable frequency drives for one or more hot pumps
127-128 Variable frequency drives for cooling tower fans
129 I/O interface
130 Memory
131 Processor
200 Data
201 Parameter data
203 Wet temperature data
205 Predefined condition data
207 Control data
209 Other data
213 Modules
215 Communication module
217 Temperature determining module
219 Validation module
221 Control value determination module
223 Other modules
600 Exemplary computer system
601 I/O Interface of the exemplary computer system
602 Processor of the exemplary computer system
603 Network interface
604 Storage interface
605 Memory of the exemplary computer system
606 User interface
607 Operating system
608 Web browser
609 Communication network
611 Input devices
612 Output devices
, Claims:1. A method of controlling a cooling tower in an industrial plant based on atmospheric conditions, the method comprising:
receiving, by a control system (101) communicatively connected with a cooling tower system (100) of a cooling tower, values of a plurality of parameters of the cooling tower from a plurality of sensors (109-119) placed at predetermined locations in the cooling tower;
determining, by the control system (101), a value of a wet bulb temperature (T2) associated with the cooling tower based on the values of the plurality of parameters;
validating, by the control system (101), a plurality of predefined conditions of each of one or more hot pumps (121-123) and cooling tower fans associated with the cooling tower based on the value of the wet bulb temperature, the values of the plurality of parameters and threshold set points; and
determining, by the control system (101), a control value for each variable frequency drive (124-128) associated with respective one or more hot pumps (121-123) and cooling tower fans based on the validation, for controlling the cooling tower.

2. The method as claimed in claim 1, wherein the plurality of parameters of the cooling tower comprises dry bulb temperature (T1), Relative Humidity (RH), cooling tower outlet temperature (T3), cold well temperature (T4), cooling tower inlet temperature (T5), Total Dissolved Solids (TDS) value, Blow Down Valve (BDV).

3. The method as claimed in claim 1, wherein the value of the wet bulb temperature (T2) is determined based on dry bulb temperature (T1) and Relative Humidity (RH).

4. The method as claimed in claim 1, wherein the plurality of sensors (109-119) comprises dry bulb temperature sensor (T1), cooling tower outlet temperature sensor (T3), a cold well temperature sensor (T4), a hot well temperature sensor (T5), a TDS sensor (TDS), a relative humidity sensor (RH).

5. The method as claimed in claim 4, wherein the dry bulb temperature sensor (T1) (109) is placed in a climatic site at which the cooling tower is located for measuring ambient air temperature.

6. The method as claimed in claim 4, wherein the cooling tower outlet temperature sensor (T3) (113) is located at cooling tower outlet line to measure cooled water temperature and the cold well temperature sensor (T4) (115) is located at a cold well (107) of the cooling tower.

7. The method as claimed in claim 4, wherein the hot well temperature sensor (T5) (117) is placed at a header of a cooling tower inlet line to measure hot water temperature and the TDS sensor (TDS) (119) is placed in a hot water inlet line to measure total dissolved solids of cooling tower inlet water, and the relative humidity sensor (RH) (111) is placed along with the dry bulb temperature sensor (T1) (109).

8. The method as claimed in claim 1, wherein the control value corresponds to a value of speed for the one or more hot pumps (121-123) and cooling tower fans.

9. The method as claimed in claim 8, wherein the speed for the one or more hot pumps (121-123) is increased when:
difference between value of cooling tower inlet temperature and cold well temperature (T5-T4) is greater than threshold differential temperature between hot well and cold well temperature; or
difference between value of the cold well temperature and cooling tower outlet temperature (T4-T3) is greater than threshold differential temperature between cold well and CT outlet temperature.
10. The method as claimed in claim 8, wherein the speed for the one or more hot pumps (121-123) is decreased when value of cooling tower inlet temperature and cold well temperature (T5-T4) is less than threshold differential temperature between hot well and cold well temperature.

11. The method as claimed in claim 8, wherein the speed of the one or more hot pumps (121-123) is maximum when a value of relative humidity is less than a minimum threshold relative humidity value.

12. The method as claimed in claim 8, wherein the speed of the one or more cooling fans is increased when difference between a value of cooling tower outlet temperature and a wet bulb temperature (T3-T2) is greater than a target value.

13. The method as claimed in claim 8, wherein the speed of the one or more cooling fans is deceased when difference between a value of cooling tower outlet temperature and a wet bulb temperature (T3-T2) is less than a target value.

14. A control system (101) for controlling a cooling tower in an industrial plant based on atmospheric conditions. comprising:

a processor (131); and
a memory (130) communicatively coupled to the processor (131), wherein the memory (130) stores processor instructions, which, on execution, causes the processor (131) to:
receive values of a plurality of parameters of the cooling tower from a plurality of sensors (109-119) placed at predetermined locations in the cooling tower;
determine a value of a wet bulb temperature (T2) associated with the cooling tower based on the values of the plurality of parameters;
validate a plurality of predefined conditions of each of one or more hot pumps (121-123) and cooling tower fans associated with the cooling tower based on the value of the wet bulb temperature, the values of the plurality of parameters and threshold set points; and
determine a control value for each variable frequency drive (124-128) associated with respective one or more hot pumps (121-123) and cooling tower fans based on the validation, for controlling the cooling tower.

15. The control system (101) as claimed in claim 14, wherein the plurality of parameters of the cooling tower comprises dry bulb temperature (T1), Relative Humidity (RH), cooling tower outlet temperature (T3), cold well temperature (T4), cooling tower inlet temperature (T5), Total Dissolved Solids (TDS) value, Blow Down Valve (BDV).

16. The control system (101) as claimed in claim 14, wherein the processor (131) determines the value of the wet bulb temperature (T2) based on dry bulb temperature (T1) and Relative Humidity (RH).

17. The control system (101) as claimed in claim 14, wherein the plurality of sensors (109-119) comprises dry bulb temperature sensor (T1), cooling tower outlet temperature sensor (T3), a cold well temperature sensor (T4), a hot well temperature sensor (T5), a TDS sensor (TDS), a relative humidity sensor (RH).

18. The control system (101) as claimed in claim 17, wherein the dry bulb temperature sensor (T1) (109) is placed in a climatic site at which the cooling tower is located for measuring ambient air temperature.

19. The control system (101) as claimed in claim 17, wherein the cooling tower outlet temperature sensor (T3) (113) is located at cooling tower outlet line to measure cooled water temperature and the cold well temperature sensor (T4) (115) is located at a cold well (107) of the cooling tower.

20. The control system (101) as claimed in claim 17, wherein the hot well temperature sensor (T5) (117) is placed at a header of a cooling tower inlet line to measure hot water temperature and the TDS sensor (TDS) (119) is placed in a hot water inlet line to measure total dissolved solids of cooling tower inlet water, and the relative humidity sensor (RH) (111) is placed along with the dry bulb temperature sensor (T1) (109).

21. The control system (101) as claimed in claim 14, wherein the control value corresponds to a value of speed for the one or more hot pumps (121-123) and cooling tower fans.

22. The control system (101) as claimed in claim 21, wherein the processor (131) increases the speed for the one or more hot pumps (121-123) when:
difference between value of cooling tower inlet temperature and cold well temperature (T5-T4) is greater than threshold differential temperature between hot well and cold well temperature; or
difference between value of the cold well temperature and cooling tower outlet temperature (T4-T3) is greater than threshold differential temperature between cold well and CT outlet temperature.
23. The control system (101) as claimed in claim 21, wherein the processor (131) decreases the speed for the one or more hot pumps (121-123) when value of cooling tower inlet temperature and cold well temperature (T5-T4) is less than threshold differential temperature between hot well and cold well temperature.

24. The control system (101) as claimed in claim 21, wherein the speed of the one or more hot pumps (121-123) is maximum when a value of relative humidity is less than a minimum threshold relative humidity value.

25. The control system (101) as claimed in claim 21, wherein the processor (131) increases the speed of the one or more cooling fans when difference between a value of cooling tower outlet temperature and a wet bulb temperature (T3-T2) is greater than a target value.

26. The control system (101) as claimed in claim 21, wherein the processor (131) decreases the speed of the one or more cooling fans when difference between a value of cooling tower outlet temperature and a wet bulb temperature (T3-T2) is less than a target value.