Drift detection device, system and method

Abstract

In one aspect, an air contactor has an airflow generator for generating an airflow, a liquid dispensing system operable to dispense liquid contacted by the airflow, and a sensor configured to detect an air variable of the airflow. The controller is configured to determine an operational variable of at least one of the gas flow generator and the liquid dispensing system. The controller is further configured to determine a drift condition of the air contactor based at least in part on an air variable of the airflow and an operational variable of at least one of the airflow generator and the liquid distribution system.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 394,687, filed on August 3, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present disclosure relates to air contactors, and in particular, to monitoring drift in air contactors. Background Art

[0003] Various types of air contactors are known, including heat exchanger systems, such as direct heat exchanger systems and indirect heat exchanger systems. Some direct heat exchanger systems operate by dispensing a hot process liquid (e.g., water) onto a packing sheet and directing ambient air through the liquid-covered packing sheet to remove heat from the process fluid. As the air passes through the liquid-covered packing sheet, heat is transferred from the liquid to the air, and the process fluid is cooled.

[0004] Some indirect heat exchanger systems are considered wet indirect heat exchanger systems, including indirect heat exchangers such as coils, pillow heat exchangers, plate heat exchangers, and / or fin-tube heat exchangers. A hot process fluid (e.g., water, steam, refrigerant) is directed through the channels of the indirect heat exchanger. The system distributes an evaporative liquid to the indirect heat exchanger and generates an airflow through the indirect heat exchanger covered by the evaporative liquid. The evaporative liquid indirectly absorbs heat from the process fluid to cool the process fluid. As the liquid travels along the outer surface of the indirect heat exchanger, a portion of the evaporative liquid evaporates.

[0005] One disadvantage of some existing heat exchanger systems that distribute liquid (e.g., distributing process liquid to filler sheets or distributing evaporative liquid to indirect heat exchangers as described above) is that some liquid particles are picked up by the air flowing through the heat exchanger and carried out of the heat exchanger. Liquid particles carried by the air flow, referred to herein as "drift," may be undesirable due to chemicals and bacteria in the liquid particles. For example, liquid particles may fall on components outside the heat exchanger, causing corrosion and / or accumulation of scale and minerals. Some heat exchangers include drift eliminators to reduce the amount of drift leaving the heat exchanger, however, such drift eliminators are generally unable to remove all drift from the air flowing through the heat exchanger. Summary of the invention

[0006] In one aspect of the present disclosure, an air contactor is provided, comprising: an airflow generator for generating an airflow; a liquid distribution system operable to distribute a liquid contacted by the airflow; and a sensor configured to detect an air variable of the airflow. The air variable may include, for example, relative humidity, temperature, and / or particulate matter of the airflow. The air contactor also includes a controller configured to determine an operating variable of at least one of the airflow generator and the liquid distribution system. For example, the airflow generator may include a fan assembly, and the liquid distribution system includes a pump. The controller may determine the airflow generator operating variable (including the speed of the fan assembly) and the liquid distribution system operating variable (including whether the pump is turned on or off). The controller is also configured to determine the drift condition of the air contactor based at least in part on the air variable of the airflow and the operating variable of at least one of the airflow generator and the liquid distribution system. In this way, the controller is able to accurately assess the drift of the air contactor using the air variable of the airflow in the air contactor and the operating variable of at least one of the airflow generator and the liquid distribution system.

[0007] The present disclosure also provides a method for operating an air contactor, which has an airflow generator that generates an airflow. The method includes operating a liquid distribution system of the air contactor to distribute a liquid, and the airflow contacts the liquid. The method also includes: detecting an air variable of the airflow by a sensor of the air contactor; and determining an operating variable of at least one of the airflow generator and the liquid distribution system. The method includes determining a drift condition of the air contactor based at least in part on the air variable of the airflow and the operating variable of at least one of the airflow generator and the liquid distribution system. The method is therefore conducive to determining a drift condition using the air variable of the airflow and the operating variable of the air contactor, rather than relying solely on sensing the airflow.

[0008] In another aspect, a device for sensing drift in an airflow of an air contactor is provided, the airflow having a first velocity in the air contactor. The device includes an inlet for receiving a portion of the airflow, and an outlet. The device also includes an airflow generator, which is configured to cause the portion of the airflow to have a second velocity corresponding to the first velocity of the airflow of the air contactor. When the portion of the airflow travels at the second velocity, the sensor is operable to detect a variable of the portion of the airflow. The corresponding air velocities inside and outside the device cause the flow rates of particles and water vapor inside and outside the device to be similar, so that the sensing of the air variables inside the device represents the sensing of the air outside the device.

[0009] A method for sensing drift in an airflow of an air contactor is also provided. The method includes determining a variable representing a first speed of the airflow of the air contactor. The method also includes controlling a drift sensing device so that a portion of the airflow entering the drift sensing device at a first speed travels in a channel of the drift sensing device at a second speed corresponding to the first speed. The method includes detecting a variable of the portion of the airflow by a sensor when the portion of the airflow travels in the channel at the second speed. The corresponding air speeds inside and outside the drift sensing device allow the sensing of the variable of the portion of the airflow in the drift sensing device to be representative of the variable of the airflow outside the drift sensing device. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1A is a schematic diagram of a direct heat exchanger system including drift measurement sensors at the outlet and inlet of the heat exchanger system.

[0011] Figure 1B yes Figure 1A Example block diagram of a cooling tower.

[0012] Figure 2 It is shown Figure 1A Example graph of the relationship between monitored variables for a heat exchanger system.

[0013] Figures 3A to 3F is to show how to use Figure 1A Example graph of a heat exchanger system with changing conditions to detect drift changes.

[0014] Figure 4 According to an implementation scheme Figure 1A Schematic diagram of the drift measurement sensor.

[0015] Figure 5 , 6 , 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34 and 35 are according to other embodiments Figure 1A Schematic diagram of the drift measurement sensor.

[0016] Fig.36A is a schematic diagram of a heat exchange device with indirect heat exchangers and drift measurement sensors at the outlet and inlet of the heat exchange device.

[0017] Fig.36B yes Fig.36A Schematic diagram of an alternative configuration of a heat exchange device, Fig.36B The heat exchange device of the invention has a drift measuring sensor between an indirect heat exchanger and a fan of the heat exchange device.

[0018] Fig.37A is a schematic diagram of a heat exchange device having an indirect heat exchanger and an adiabatic precooler upstream of the indirect heat exchanger, the heat exchange device comprising drift measurement sensors at the air outlet and the air inlet of the heat exchange device.

[0019] Fig.37B yes Fig.37A Schematic diagram of an alternative configuration of a heat exchange device, Fig.37B The heat exchange device has a drift measuring sensor between the adiabatic cooler and the indirect heat exchanger of the heat exchange device.

[0020] Fig.38 , 39 , 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, and 53 are schematic diagrams of drift measurement sensors according to other embodiments.

[0021] Fig.54 and Fig.55 According to other embodiments Figure 1A Schematic diagram of the drift measurement sensor.

[0022] Figures 56A to 56E Instructions on how to use Figure 1A Example graph of a heat exchanger system with changing conditions to detect drift changes. DETAILED DESCRIPTION

[0023] In one aspect of the present disclosure, a drift measurement sensor is disclosed, which can be used to monitor the condition of an air contactor to determine the drift rate and / or change in the drift rate of the air contactor. The air contactor contacts a process fluid, such as a liquid or a liquid / gas mixture (e.g., water and water vapor), with air. The air contactor can, for example, transfer heat and / or mass between the fluid and the air. Examples of air contactors include air pollutant capture systems, packed absorption towers, rotary dryer systems, and heat exchange devices (e.g., cooling tower 100). The drift measurement sensor can be installed at the air inlet and / or outlet of the cooling tower, and includes one or more sensors to monitor air variables of the air flowing into and out of the cooling tower. The air variables can include variables representing the air itself, such as dry bulbs, wet bulbs, and / or air pressure, as well as variables representing particles carried by the air. The particles carried by the air can include, for example, liquid water, aqueous solutions, and / or other liquids, such as carbon dioxide capture solutions. In one embodiment, the drift (e.g., liquid water droplets) can be condensed and collected, and the one or more sensors include sensors for detecting variables of the liquid, such as conductivity, pH, alkalinity, free chlorine, oxidation-reduction potential (ORP), and / or microorganisms of the collected water. As another example, the air variable can include a particulate matter sensor configured to detect the accumulation rate of particles of different sizes (e.g., salts and other minerals dissolved in the drifting liquid water droplets). The cooling tower 100 can include a controller 162 configured to monitor operating variables of the cooling tower, such as the speed of a fan assembly of the cooling tower, whether a liquid distribution system of the cooling tower is dispensing liquid, and / or variables of the liquid distributed by the liquid distribution system. The controller 162 can be configured to determine a drift condition based on changes in the air variables and the operating variables of the cooling tower 100, such as an unacceptable change in the drift rate.

[0024] The drift measurement sensor described herein can be used in various air contactors to determine drift conditions. For example, one or more drift measurement sensors disclosed herein can be used with an air pollutant capture device that removes pollutants from the air. For example, the air pollutant capture device can utilize a capture medium, such as a liquid capture solution (e.g., a CO2 capture solution) and a support (e.g., a filler sheet). The liquid capture solution may include, for example, an aqueous solution of a hydroxide or potassium hydroxide. The liquid capture solution can be sprayed onto the filler sheet, the CO2 capture solution travels along the filler sheet and entrains CO2 in the air into the liquid, and the CO2 capture solution is collected in a liquid collection tank of the air pollutant capture device. In some cases, spraying the carbon dioxide capture solution onto the filler may cause the carbon dioxide capture solution to drift within the air pollutant capture device. A controller associated with the air pollutant capture device can utilize air variables (e.g., pH values ​​of CO2 capture solution drift) and operating variables of the air pollutant capture device to determine whether the detected drift change is unacceptable, and adjust the operation of the air pollutant capture device to resolve the drift condition.

[0025] refer to Figure 1A , a heat exchange device (e.g., a cooling tower 100) is provided that monitors changes in drift within the cooling tower 100. Although a cooling tower is provided herein by way of example, the concepts disclosed in the following discussion can be similarly used for other heat exchanger systems, including, for example, swamp coolers, building humidification systems, air handlers, and various applications, such as heat exchanger systems for hospitals, greenhouses, and / or livestock farming. The heat exchanger system can utilize a direct heat exchanger, a wet indirect heat exchanger, and / or adiabatic cooling. In addition, although a cooling tower 100 with a direct heat exchanger is provided by way of example, the concepts disclosed in the following discussion can be similarly used for other heat exchange systems that discharge liquids, such as indirect heat exchangers. The cooling tower 100 has an airflow generator (e.g., a fan assembly 102) and a heat exchanger 103 (e.g., a direct heat exchanger including a filler 104) and a liquid distribution system 106 for distributing a process fluid to the filler 104.

[0026] The fan assembly 102 includes a fan 110 and a motor 112 that rotates the fan to generate an airflow along a path 114 relative to a housing 115 of the cooling tower 100. Specifically, the fan assembly 102 draws air into an air inlet 118 of the housing 115, through the outer surface of the fill 104, and from the fill 104 to an outlet 130. The air inlet 118 may include a filter 120 mounted within an opening of the air inlet 118 that filters debris from the air upstream of the fill 104. Alternatively or additionally, the air inlet 118 may include a damper (e.g., a shutter) that prevents liquid from splashing out or leaving the cooling tower 100 through the air inlet 118. The shutter may also prevent ultraviolet light from directly contacting the water, which may, for example, inhibit the growth of algae. The fan assembly 102 includes one or more sensors for monitoring the operation of the motor 112, such as a motor speed sensor 102A and a motor power sensor 102B.

[0027] While flowing through the fill 104, the air flows through the drift eliminator 122. The drift eliminator 122 provides a tortuous path for the airflow so that as the air travels through the drift eliminator 122, water in the air strikes and collects on the surface of the drift eliminator 122. For example, the drift eliminator 122 may include vanes or baffles through which the air and drift flow from the fill 104 to the outlet 130. The baffles may form a curved and / or angled flow path that changes the direction of the air flowing through the drift eliminator 122 so that the drift in the air strikes the baffles and collects in the drift eliminator 122. For example, when the drift strikes the baffles, the drift loses velocity and collects on the inner surface of the drift eliminator 122. The water collected by the drift eliminator 122 travels downwardly into the sump 132 under the action of gravity.

[0028] Although drift eliminators reduce drift in the air, conventional drift eliminators are unable to remove all drift from the air and allow some drift to pass through. Specifically, drift having smaller particle sizes (e.g., less than 10 microns) is often able to flow through conventional drift eliminators. Drift having such smaller particle sizes may be carried great distances in the air and, as described above, may contain chemicals and / or bacteria. It may be desirable to limit drift in the cooling tower 100 downstream of the drift eliminator 122, as well as to limit drift discharged from the cooling tower 100.

[0029] The liquid distribution system 106 includes a conduit 124 through which a process fluid flows to the cooling tower 100. The process fluid may include, for example, water and / or glycol (e.g., propylene, ethylene). The process fluid may be a fluid heated by a chiller system and transported to the cooling tower 100 for cooling. The liquid distribution system 106 includes a pump 126, which is operable to pump the process fluid through the conduit 124 and into the cooling tower 100. The pump 126 may operate in response to a control signal from a controller 162. For example, the pump 126 may receive a control signal to operate at a certain speed. A speed sensor 127 may monitor a speed variable of the pump 126, such as a pump RPM. The speed sensor 127 may collect speed data and send it to the controller 162. A power sensor 128 may monitor a power variable associated with the power consumed by the pump 126, such as kW. The power sensor 128 may collect power data and communicate it to the controller 162. The liquid distribution system 106 may include a temperature sensor 146 for detecting a temperature variable, such as degrees Fahrenheit (°F), of the process fluid flowing into the conduit 124 of the cooling tower 100. The liquid distribution system 106 may include a flow meter 148 for detecting a flow variable, such as gallons per minute, of the process fluid flowing through the conduit 124 into the cooling tower 100. The controller 162 may receive data from the temperature sensor 146 and / or the flow meter 148.

[0030] The liquid distribution system 106 includes one or more openings, such as nozzles 129, through which the process fluid is pumped and distributed to the filler 104. The nozzle 129 can be fluidly connected to the conduit 124 so that the process fluid pumped by the conduit 124 is pumped through the nozzle 129. The nozzle 129 sprays the process fluid onto the filler 104, and the process fluid flows through the filler 104 and drains into the sump 132. As some examples, the filler 104 can include cubes and / or thin sheets. In one embodiment, the filler 104 includes thin sheets, and the process fluid travels downward along the ridges, valleys, etc. of the outer surface of the filler sheet under the influence of gravity. In another embodiment, the liquid distribution system can include one or more slots with openings that allow the liquid to fall onto the filler below the slot.

[0031] As the process fluid flows through the fill 104 to the sump 132, the process fluid is cooled by the airflow generated by the fan assembly 102. The rotation of the fan 110 causes air to move from the air inlet 118, through the fill 104, up through the fan assembly 102, and out of the air outlet 130 of the cooling tower 100. In one approach, the temperature of the process fluid flowing through the fill 104 is higher than the temperature of the air flowing through the fill 104, such that heat is transferred from the higher temperature process fluid to the cooler airflow moving through the fill 104.

[0032] The cooled process fluid is collected in the sump 132 and exits the cooling tower 100 through the outlet 133. For example, the pump 135 can direct the cooled process fluid to a chiller system. The cooling tower 100 can include a fill level sensor 136, such as a float, which provides a signal indicating the volume of liquid in the sump. The cooling tower 100 can include a temperature sensor 158 and a conductivity sensor 160 within the sump 132 for monitoring the temperature and conductivity of the fluid within the sump 132. The controller 162 can receive data from the temperature sensor 158 and / or the conductivity sensor 160. The cooling tower 100 can additionally or alternatively include sensors for measuring other variables of the fluid in the sump 132, such as pH, alkalinity, free chlorine, oxidation-reduction potential (ORP), and / or microorganisms of the fluid within the sump 132. The sump 132 may have a drain valve 138 that may be opened to drain fluid from the sump 132 and out of circulation within the cooling tower 100. For example, the drain valve 138 may be opened to drain fluid from the sump 132 when the conductivity and / or pH of the process fluid exceeds a threshold, such as as part of a fluid switching process.

[0033] The cooling tower 100 may include one or more drift measurement sensors 150 to monitor one or more variables of the cooling tower 100, such as variables related to air quality conditions. Figure 1A , the cooling tower 100 may include a drift measurement sensor 150 located at the air outlet 130 and one or both air inlets 118 of the cooling tower 100. The drift measurement sensor 150 may include a sensor for monitoring a variable indicative of drift, as discussed in more detail below.

[0034] In one embodiment, one or more drift measurement sensors 150 include a temperature sensor 152, a relative humidity sensor 154, and a particle sensor 156. The temperature sensor 152 can detect the dry bulb temperature of the air. The particle sensor 156 is operable to detect the number of particles in the air, for example, water particles carried in the air and / or carried in droplets in the air. The particle sensor 156 can provide a rate of particles (e.g., particle counts per minute or per hour). The particle sensor 156 can detect particles in the air such as dust, smoke, smog, and other chemicals or pollutants, such as those emitted by power plants, industrial facilities, and / or automobiles. Some particle sensors 156 may include a membrane configured to allow particles of a specific size to pass through. The particle sensor 156 may be operable to detect particles passing through the membrane to measure the amount of particles in the air and drift. Some particle sensors 156 can use light scattering techniques to detect the concentration of particles in the air, for example, passing a light beam through an air sample and detecting the scattering of the light beam by particles in the air sample. The particulate matter sensor 156 may include multiple sensors for detecting particles of different size ranges, for example, a PM2.5 sensor for detecting particles less than 2.5 microns in width and a PM10 sensor for detecting particles less than 10 microns in width. Other particulate matter sensors may additionally or alternatively be used to measure particles of other sizes, for example, a PM1 sensor for detecting particles less than 1 micron in width.

[0035] refer to Figure 1B, the cooling tower 100 is associated with a controller 162, which controls the operation of the cooling tower 100, which includes a fan assembly 102 and a liquid distribution system 106. The controller 162 can be integrated with the cooling tower 100 or away from the cooling tower 100. The controller 162 includes a processor 164, a memory 166, and a communication circuit 168. The processor 164 communicates with the memory 166 to provide functions for the cooling tower 100. The processor 164 can be configured to provide information processing capabilities and can include multiple processing units that communicate with each other. As an example, the processor 164 may include a digital processor, an analog processor, a PID controller, a microprocessor, a microcontroller, an application specific integrated circuit (ASIC), and / or a system on a chip. The memory 166 can store logic, instructions, and operating variables accessible to the processor 164 to operate the cooling tower 100. The memory 166 may include, for example, RAM, DRAM, SDRAM, EEPROM, ROM, flash memory, and / or a hard drive. As an example, the communication circuit 168 may include a wired and / or wireless interface. Examples include an Ethernet interface, a Wi-Fi network interface, and / or a Bluetooth interface. The processor 164 receives data from sensors of the cooling tower 100 to monitor the operation of the cooling tower 100. For example, the processor 164 can receive data from the drift measurement sensor 150, the inlet process fluid temperature sensor 146, the flow sensor 148, the pump speed sensor 127, the pump power sensor 128, the sump fluid temperature sensor 158, the sump fluid conductivity sensor 160, and other sensors of the cooling tower 100. The processor 164 can receive control signals from a remote computer (e.g., an HVAC system controller) via the communication circuit 168 and communicate data with the remote computer. As another example, the processor 164 can communicate with a remote device (e.g., a server computer) and / or a technician's portable electronic device (e.g., a smart phone, tablet, or laptop).

[0036] The processor 164 can receive a control signal including a set point temperature of the process fluid (e.g., the temperature of the process fluid leaving the cooling tower 100 through the outlet 133). The processor 164 can determine the operating variables of the cooling tower 100 to meet the set point temperature. For example, the processor 164 can control the speed of the inlet pump 126 and / or the fan assembly 102. The processor 164 can communicate the control signal to the fan assembly 102 and / or the liquid distribution system 106 to meet the set point temperature. The processor 164 can communicate the control signal to the fan assembly 102 and / or the liquid distribution system 106 via the communication circuit 168. As an example, the controller 162 can be connected to a plurality of cooling towers 100 and configured to operate each cooling tower 100 to meet the cooling demand of the associated building. The communication circuit 168 can be configured to communicate via a wired and / or wireless communication protocol (e.g., Ethernet, Wi-Fi, Bluetooth, cellular, etc.).

[0037] The controller 162 operates the fan assembly 102 to generate airflow through the cooling tower 100. The controller 162 can operate the fan assembly 102 to draw air through the fill 104 to cool the fluid flowing through the fill 104. The controller 162 can also operate the liquid distribution system 106 to control the distribution of the process fluid on the fill 104. For example, the controller 162 can adjust the speed of the feed pump 126 to increase or decrease the flow rate of the process fluid through the conduit 124.

[0038] Operating the fan assembly 102 and / or the feed pump 126 at high or low speeds may increase drift in the air downstream of the drift eliminator 122. As described above, the drift eliminator 122 is generally unable to remove all drift from the air, so the drift may flow toward the fan assembly 102 and out of the cooling tower 100. Drift eliminators are generally most effective in the middle of the designed airflow velocity range and less effective at lower and higher airflow velocities within the designed airflow velocity range.

[0039] Drift leaving a cooling tower is generally undesirable due to, for example, corrosion caused by drift, mineral deposits left behind by drift, and the visual appearance of drift as it leaves the cooling tower 100. The controller 162 can detect drift of the cooling tower 100 by monitoring variables of the cooling tower 100. In one embodiment, the controller 162 detects changes in drift based on changes in variables of the cooling tower 100 collected by sensors of the cooling tower 100, and responds accordingly. For example, if the controller 162 determines that drift downstream of the drift eliminator 122 is increasing, the controller 162 can adjust the operation of the cooling tower 100 to reduce drift and / or warn a user that drift is increasing, such as by sending an SMS message or email.

[0040] refer to Figure 2, an example graph 200 is provided that illustrates a relationship between variables monitored by a cooling tower 100 that may be used to determine a change in the drift rate of the cooling tower 100. The controller 162 may receive data from the drift measurement sensors 150 mounted at the air inlet 118 and the air outlet 130 of the cooling tower 100. Line 202 indicates the amount of particulate matter less than 2.5 microns detected by the particle sensor 156 of the drift measurement sensor 150 at the air inlet 118 of the cooling tower 100 over time. Line 204 indicates the amount of particulate matter less than 10 microns detected by the particle sensor 156 of the drift measurement sensor 150 at the air inlet 118 of the cooling tower 100 over time. Line 206 indicates the speed of the fan assembly 102 when the controller 162 operates the fan assembly 102 to cool the process fluid flowing through the fill 104 over time. Line 208 indicates the process fluid 134 in the sump 132 (see Figure 1A ) over time. The controller 162 may detect the conductivity of the liquid using the conductivity sensor 160 of the sump 132. As the process fluid is recirculated through the cooling tower 100, some of the water in the process fluid may evaporate, which increases the concentration of salts and other particulates in the water and causes the conductivity of the liquid to increase. Line 210 indicates the amount of particulate matter having a particle size of less than 2.5 microns detected by the particle sensor 156 of the drift measurement sensor 150 at the air outlet 130 of the cooling tower 100 over time. Line 212 indicates the amount of particulate matter having a particle size of less than 10 microns detected by the particle sensor 156 at the air outlet 130 of the cooling tower 100 over time. The controller 162 may monitor changes in the particulate matter at the air outlet 130 to determine whether the drift rate of the cooling tower 100 is increasing or whether the amount of particulate matter at the air outlet 130 is attributable to other factors, such as changes in the drift rate of the cooling tower 100. FIG. 3A to FIG. 3F As shown, as the conductivity of the fluid increases (as shown by line 208 ), the amount of particulate matter detected at the air outlet 130 of the cooling tower 100 increases, which may indicate that the drift rate of the cooling tower 100 increases.

[0041] refer to FIG. 3A to FIG. 3F, example graphs are provided that illustrate how changing conditions of the cooling tower 100 can be used to detect changes in the drift rate of the cooling tower 100. In these examples, the controller 162 monitors cooling tower variables, including cooling tower operating variables, such as the speed of the fan assembly 102, whether the liquid distribution system 106 is dispensing liquid, and the conductivity of the liquid distributed by the liquid distribution system 106. The cooling tower operating variables also include air variables, such as particulate matter (PM2.5 and PM10) at the air inlet 118 and the air outlet 130 of the cooling tower 100, and the relative humidity and temperature of the air at the air inlet 118 and the air outlet 130 of the cooling tower 100. These conditions are provided by way of example, and fewer or more variables can be monitored and / or used to evaluate drift conditions. For example, the controller 162 can monitor the flow rate of the liquid distribution system 106. Based on the monitored variables, changes in the drift rate of the cooling tower 100 can be detected. For example, a change in the amount of particulate matter at the air outlet 130 may be evaluated to determine whether the change is due to a change in drift rate, or whether the change is attributable to other changing conditions of the cooling tower 100. In some embodiments, the controller 162 may be programmed to evaluate the changing conditions of the cooling tower 100 to determine whether the change is due to a change in drift rate, or whether the change is attributable to other changing conditions of the cooling tower 100. FIG. 3A to FIG. 3F The example discussed determines whether the drift rate of the cooling tower 100 is a normal amount of change or an abnormal amount of change. If the controller 162 determines that the change in the drift rate is abnormal or unacceptable, the controller 162 can be programmed to change the operation of the cooling tower 100 to reduce the drift rate, such as changing the cooling tower 100 from a wet mode to a dry mode, reducing the fan speed, and / or notifying a maintenance worker. The fan speed is provided as a decimal representing a percentage, such as 0.80 indicating that the fan assembly is operating at 80% of the maximum fan speed.

[0042] refer to Figure 3A , an example graph 300 is provided in which the condition of the cooling tower 100 changes from a baseline condition ("baseline 1") to a new condition A or a new condition B. When changing from baseline 1 to new condition A, the conductivity 302 of the liquid in the liquid distribution system 106 increases from 1250 μS / cm to 1550 μS / cm. Similarly, the amount of PM2.5 and PM10 particulate matter 304 at the outlet 130 increases from 25 μg / cm to 300 μg / cm, respectively. 3 and 30 μg / cm 3 Increased to 28μS / cm 3 and 34μS / cm 3The increase in particulate matter at the outlet 130 may be attributed to an increase in the conductivity of the liquid of the liquid distribution system 106. For example, the amount of particulates in the drifting droplets carried from the fill 104 may have increased because the concentration of particles in the process fluid of the liquid distribution system 106 has increased, as shown by the increase in conductivity 302. However, the amount of droplets carried in the gas stream may have increased within a predetermined range of an expected increase in the amount of droplets carried in the gas stream, which may be attributed to an increase in water surface tension due to an increase in the concentration of particles in the process fluid. Therefore, the system controller determines that an expected or normal change in the drift rate of the cooling tower 100 has occurred.

[0043] When changing from baseline 1 to new condition B, the amount distribution of PM2.5 and PM10 particles 308 detected at the outlet 130 of the cooling tower 100 changes from 25 μS / cm 3 and 30μS / cm 3 Increase to 35μS / cm 3 and 42μS / cm 3 , while the other monitored variables remain unchanged. The controller 162 determines that the drift rate of the cooling tower 100 has increased abnormally because other variables of the cooling tower 100 have not changed to cause an increase in the amount of particulate matter at the air outlet 130, and the change in the amount of particulate matter exceeds a predetermined range of expected changes in particulate matter. For example, the controller 162 may determine that the increase in particulate matter is not the result of a change in another monitored variable of the cooling tower 100, but is caused by an increase in the drift rate of the cooling tower 100.

[0044] refer to Figure 3B , an example graph 310 is provided, which shows an evaluation of the effect of the change in the rotation speed of the fan assembly 102 on the drift rate determination. When changing from baseline 2 to new condition C, the rotation speed 311 of the fan assembly 102 increases by 20%, and the amount of PM2.5 and PM10 particles 312 at the outlet 130 increases from 17μg / cm3 to 27μg / cm3, respectively. 3 and from 19 μg / cm 3 Increased to 32 μg / cm 3 The increase in PM2.5 and PM10 particulate matter may be attributed to the increase in the rotational speed of the fan assembly 102, without the drift rate of the cooling tower 100 being significantly increased or exceeding the expected drift rate of the cooling tower 100 under these operating conditions. For example, increasing the rotational speed of the fan assembly 102 may cause a greater volume of air to move relative to the PM2.5 and PM10 sensors, thereby resulting in higher PM2.5 and PM10 readings.

[0045] When changing from baseline 2 to new condition D, the speed 314 of the fan assembly 102 increases by 5%, and the amount of PM2.5 and PM10 particulate matter 315 detected increases by more than double. For example, the magnitude of the increase in PM2.5 and PM10 particulate matter is higher due to the increase in the speed of the fan assembly 102 than when changing from the same baseline 2 to new condition C. It can be determined that the drift rate of the cooling tower 100 has increased because the increase in particulate matter at the air outlet 130 cannot be attributed entirely to an increase in the speed of the fan assembly 102 or any other monitored condition. In other words, as with new condition C, some of the increase in PM2.5 and PM10 particulate matter readings can be attributed to the increase in the speed of the fan assembly 102; however, when the magnitude of the increase in the PM2.5 and PM10 particulate matter readings is disproportionately high compared to the increase in the speed of the fan assembly 102 in new condition D, it can be determined that the drift rate has increased abnormally, for example, exceeding an acceptable or expected drift rate for the cooling tower 100 under these operating conditions. Although particulate matter increases when changing from Baseline 2 to New Condition C and New Condition D, only the increase in particulate matter from Baseline 2 to New Condition D is considered abnormal and triggers a determination of an unacceptable or abnormal increase in drift.

[0046] refer to Figure 3C , an example graph 320 is provided that illustrates an assessment of the magnitude change in particulate matter at the air inlet 118 of the cooling tower 100 while other monitored variables remain constant. When changing from the baseline condition of baseline 3 to new conditions E and F, the amount of PM2.5 and PM10 particulate matter 321, 322 at the air inlet 118 increases by the same amount. Then, when changing to new condition F, the amount of PM2.5 and PM10 particulate matter 323 at the air outlet 130 increases by a greater amount than the amount of PM2.5 and PM10 particulate matter 324 during the transition from baseline 3 to new condition E. For new condition E, the increase in PM2.5 and PM10 particulate matter 324 at the air outlet 130 can be attributed to the increase in particulate matter entering the cooling tower 100 at the air inlet 118, and therefore it can be determined that the drift rate has not increased significantly. For new condition F, the particulate matter 323 at the air outlet 130 increases significantly and / or disproportionately relative to the increase in particulate matter at the air inlet 118 (e.g., compared to the change from the baseline condition of baseline 3 to new condition E). Therefore, it can be determined that the drift rate of the cooling tower 100 has increased abnormally, exceeding the acceptable or expected drift rate under these conditions.

[0047] refer to Figure 3D, an example graph 330 is provided, which shows an evaluation of the change in the rotation speed of the fan assembly 102 and the change in the conductivity of the liquid of the liquid distribution system 106. When changing from the baseline condition of baseline 4 to the new conditions G and H, the rotation speed 331, 332 of the fan assembly decreases by 15%, while the conductivity 333, 334 of the water increases. However, under the new condition H, the amount of PM2.5 and PM10 particles 336 at the outlet 130 of the cooling tower 100 is greater than the amount of particles 335 under the new condition G. Under the new condition G, although the rotation speed 331 of the fan assembly 102 is reduced, the increase in PM2.5 and PM10 particles 335 at the outlet 130 can be attributed to the increase in the conductivity of the liquid of the liquid distribution system 106, so the drift rate does not increase significantly. Under the new condition H, the amount of particulate matter 336 at the air outlet 130 increases significantly and / or disproportionately relative to the increase in the conductivity 334 of the liquid in the liquid distribution system 106 and the decrease in the speed 332 of the fan assembly 102 (e.g., compared to the change to the new condition G). The controller 162 determines that the increase in particulate matter 336 at the air outlet 130 is due to an abnormal increase in the drift rate of the cooling tower 100 that is beyond the acceptable or expected drift rate under these conditions because the increase in particulate matter 335 cannot be attributed entirely to an increase in the conductivity 334 of the liquid or any other monitored condition.

[0048] refer to Figure 3E and Fig.36A, an example chart 340 of a heat exchange device (e.g., heat exchange device 700) having an indirect heat exchanger is provided. Chart 340 shows an evaluation of a change in the speed of the fan assembly 702 and the position at which the liquid distribution system 706 begins to distribute fluid on the indirect heat exchanger (e.g., pillow plate heat exchanger 717). For example, in addition to passing cool air over the pillow plate heat exchanger 717 through the fan assembly 702, the liquid distribution system 706 can also be turned on to spray water on the pillow plate heat exchanger 717 to help cool the process fluid. When changing from the baseline condition of baseline 5 to the new conditions I and J, the speed 341, 342 of the fan assembly 702 is reduced by 35% and the liquid distribution system 706 is turned on 343, 344. Under the new condition J, the amount of PM2.5 and PM10 particles 345 at the outlet 713 of the heat exchange device 700 is greater than the particles 346 under the new condition I. With respect to the change to new condition I, the increase in PM2.5 and PM10 particulate matter at the air outlet 713 can be attributed to the liquid dispensing system 706 now spraying or dispensing liquid, even when the speed of the fan assembly 702 is reduced, and is not indicative of a significant increase in the drift rate. With respect to the change to new condition J, the increase in particulate matter 345 at the air outlet 713 is significantly greater than the increase attributable solely to the spraying of liquid by the liquid dispensing system 706. Because the increase in particulate matter 345 at the air outlet 713 is not entirely attributable to the monitored conditions, it is determined that the drift rate of the heat exchange device 700 has increased to exceed the acceptable or expected drift rate of the heat exchange device 700 under these operating conditions.

[0049] refer to Figure 3F , an example chart 350 is provided, which shows an evaluation of the change in particulate matter at the outlet 713 of the heat exchange device 700 to determine whether the drift rate has changed. When changing from the baseline condition of baseline 6 to the new condition K, the rotation speed 351 of the fan assembly 702 is reduced, the liquid distribution system 706 remains closed 352 (e.g., not spraying liquid), the particulate matter 353 at the inlet 711 increases, and the particulate matter 354 at the outlet 713 increases. When changing to the new condition K, the drift rate does not increase because when the liquid distribution system 706 is closed and no liquid is distributed, a large amount of drift cannot occur. When the liquid distribution system 706 is closed, no droplets are sprayed out by the liquid distribution system 706 and are swept away by the air flowing from the inlet 711 to the outlet 713. Therefore, the increase in particulate matter at the outlet 713 can be attributed to the increase in particulate matter entering the heat exchange device at the inlet 711.

[0050] In changing from baseline 6 to new condition L, the speed 355 of fan assembly 702 decreases, liquid distribution system 706 is turned on 356, the conductivity 357 of the liquid in the liquid distribution system decreases, particulate matter 358 at air inlet 711 increases, and particulate matter 359 at air outlet 713 increases. Although the fan speed and the conductivity of the liquid decrease, the particulate matter at air outlet 713 increases significantly. The significant increase in particulate matter at air outlet 130 cannot be entirely attributed to the increase in particulate matter at air inlet 711 and the turning on of liquid distribution system 706. Therefore, controller 162 can determine that the drift rate of heat exchange device 700 has increased to exceed an acceptable or expected drift rate under these conditions.

[0051] In some forms, a controller 162 of a heat exchange device (e.g., cooling tower 100 or heat exchange device 700) monitors changes in conditions of the heat exchange device and determines whether the drift rate has increased. To determine whether the drift rate of the heat exchange device has changed (e.g., increased), the controller 162 may compare the changes in conditions of the heat exchange device with a data set known to correspond to changes in drift conditions or a data set known to correspond to no significant changes in drift conditions (e.g., FIG. 3A to FIG. 3F In some forms, controller 162 processes the monitored variables using a machine learning algorithm to determine, for example, whether an increase in particulate matter at the outlet of the heat exchange device is attributable to a change in the condition of the heat exchange device, or is the result of an increase in the drift rate of the heat exchange device.

[0052] In the event that the controller 162 determines that the drift rate of the heat exchange device has increased, the controller 162 may send an alert indicating that the drift rate of the heat exchange device has increased. The controller 162 may alert an operator of the heat exchange device to allow the operator to measure the amount of drift, such as by another method, to verify whether drift exists and / or to determine whether the drift is an acceptable amount, to determine whether to adjust the operation of the heat exchange device, and / or to investigate the cause of the increased drift rate. The controller 162 may enter a fail-safe operating mode to operate the heat exchange device to reduce drift, such as operating in a dry mode or reducing the flow of evaporative liquid sprayed onto an indirect heat exchanger of the heat exchange device. In some forms, the controller 162 may notify a controller of a building's HVAC system that the drift rate of the heat exchange device is increasing to allow the HVAC system to adjust the operation of the HVAC system to reduce the drift of the heat exchange device.

[0053] Although the above example describes that the controller 162 determines whether the drift rate is acceptable based on the changing variables of the cooling tower, the controller 162 can also determine whether the drift rate of the cooling tower is acceptable based on the current variables of the cooling tower, without, for example, evaluating the change of the drift rate relative to the changing cooling tower variables. In other words, given the air quality conditions when the cooling tower is operating, the controller 162 can evaluate whether the drift rate of the cooling tower is acceptable when operating with certain operating variables at a given time. For example, the controller 162 can determine whether the drift rate is normal or abnormal by comparing the variables of the cooling tower with a data set of cooling tower variables known to correspond to normal or abnormal drift conditions. As another example, the controller 162 can use a machine learning algorithm to evaluate whether the drift rate of the cooling tower is acceptable for the current cooling tower operating variables and air variables.

[0054] refer to Figure 4, a drift measurement sensor 150 is shown according to one embodiment. The drift measurement sensor 150 includes a conduit, such as a tube 170, which defines a channel 172 through which air can flow through the drift measurement sensor 150. The tube 170 may have a sidewall extending around the channel 172. The drift measurement sensor 150 includes: an inlet 174 through which air can flow into the channel 172; and an outlet 176 through which air can leave the channel 172. The drift measurement sensor 150 includes one or more sensors mounted to the conduit 170 for measuring the condition of the air flowing through the channel 172 of the drift measurement sensor 150. The drift measurement sensor 150 may include a temperature sensor 152, a relative humidity sensor 154, and a particulate matter sensor 156 (e.g., one or more sensors for measuring PM2.5 and PM10). These sensors may be mounted closer to the outlet 176 of the drift measurement sensor 150 than the inlet 174, which may, for example, help ensure that the airflow through the drift measurement sensor 150 is substantially uniform. The sensors may be mounted within the passage 172 such that the sensors minimize obstruction to the flow of air, particles, and debris through the passage 172. This may ensure accurate readings of air quality variables while minimizing the accumulation of droplets, particles, and debris on the sensors and within the passage 172. The drift measurement sensor 150 may be positioned in the path of the airflow 114 through the cooling tower 100, with the inlet 174 of the drift measurement sensor 150 located upstream of the outlet 176 to direct the airflow into the inlet 174 of the drift measurement sensor 150. As shown in FIG. 1 , the drift measurement sensor 150 may be positioned at the air inlet 118 and the air outlet 130 of the cooling tower 100 to monitor air conditions as the air enters the cooling tower 100 and as the air leaves the cooling tower 100. In one embodiment, the drift measurement sensor 150 includes a conductivity sensor for collecting water and detecting the conductivity of the collected water (see, for example, Fig. 20 and Fig.21 ). The drift measurement sensor 150 may include a controller 151 that controls the operation of the components of the drift measurement sensor 150, including the sensors 152, 154, 156. The controller 151 may communicate with a controller 162 of the cooling tower 100 and facilitate data communication between the sensors 152, 154, 156 and the controller 151. In some forms, the controller 151 is omitted and the controller 162 of the cooling tower 100 controls the operation of the components of the drift measurement sensor 150. It should be understood that other embodiments of the drift measurement sensors disclosed herein may include controllers similar to the controller 151, but for clarity, these controllers are generally omitted from the relevant figures.

[0055] refer to Figure 5, the drift measurement sensor 150 may also include a dehumidifier, such as a heater 178. The heater 178 may be mounted to the conduit 170 and may be operated to dry the air entering the inlet 174 of the drift measurement sensor 150. The heater 178 may be mounted upstream of the sensor of the drift measurement sensor 150 to dry the air before the air passes through the sensor. The heater 178 dries the air by raising the dry bulb temperature of the air (which reduces the relative humidity of the air). The heater 178 may be used to reduce the relative humidity of the air and / or evaporate drift droplets so that the PM2.5 sensor, PM10 sensor and other sensors of the drift measurement sensor can operate correctly. In another embodiment, the dehumidifier of the drift measurement sensor 150 may include a vapor permeable membrane configured to remove water vapor in the air. The membrane may be water permeable while being non-permeable to salt and other dissolved solids. The size and shape of the membrane may be designed to limit particle aggregation on the membrane while allowing efficient removal of moisture.

[0056] Drying the air flowing into the drift measurement sensor 150 can reduce the accumulation of drifted water droplets entering the drift measurement sensor 150 on the sensor in the channel 172. The accumulation of water on the sensor may reduce the accuracy of the sensor measurement and may cause sensor failure. In some forms, the particle sensor 156 is capable of detecting salts left by evaporated water droplets. Therefore, even when the heater 178 causes the water in the drifting water droplets to evaporate, the drift measurement sensor 150 is able to detect particulate matter in the airflow. The heater 178 can be installed to minimize the obstruction of the channel 172 while heating the air flowing through the channel 172. This configuration allows the heater 178 to heat the air while minimizing the accumulation of droplets, particles and debris on the heater 178 and in the channel 172 that may interfere with the sensor readings downstream of the heater 178. For example, the heater 178 can be flush with the inner surface of the tube 170.

[0057] The controller 151 may operate the heater 178 based on the temperature and / or relative humidity of the air. For example, when the humidity of the air is high, the controller 151 may operate the heater 178 to dry the air and prevent water from accumulating inside the tube 170, the sensor, or other parts of the drift measurement sensor 150. For example, the controller may be programmed to calculate the probability of plume formation based on the temperature and humidity of the air, and operate the heater 178 to reduce the probability of plume formation and condensation (e.g., within the drift measurement sensor 150).

[0058] refer to Figure 6, the drift measurement sensor 150 may include a cooler 180, such as a cooling coil. The cooler 180 may be mounted within the channel 172 and may be operated to cool air entering the inlet 174 of the drift measurement sensor 150. The cooler 180 may be mounted upstream of the sensor of the drift measurement sensor 150 and used to condense water in the air before the air flows through the sensor. As with the heater 178, drying the air flowing into the drift measurement sensor 150 may help reduce the accumulation of water and moisture on the sensor within the channel 172. The cooler 180 may condense moisture in the air and collect drift droplets within the channel 172 before the droplets reach the sensor. The cooler 180 may be mounted in the channel 172 to minimize obstruction of the channel 172 while cooling the air flowing through the channel 172. This configuration allows the cooler 180 to cool the air and condense moisture in the air while minimizing the accumulation of droplets, particles, and debris on the cooler 180 and within the channel 172 that may interfere with the sensor readings downstream of the cooler 180. For example, the cooler 180 may have a cooling surface that is flush with the inner surface of the tube 170. In some embodiments, the cooler 180 may collect moisture condensed from the air and measure the conductivity of the condensed water to determine the drift rate of the cooling tower, as described below with respect to Fig. 20 The drift measurement sensor 400 is described in further detail.

[0059] refer to Figure 7 In another embodiment, the drift measurement sensor 150 may include a heater 178 and a cooler 180. The heater 178 and the cooler 180 may be mounted within the passage 172 to dry the air before it reaches the sensor, as described above. The cooler 180 may cool the air and condense moisture in the air before it flows through the heater 178. The heater 178 may heat the air and may also help dry the air before it flows through the sensor. The heater 178 may be operated to restore the temperature of the air to the temperature of the air entering the inlet 174. Although the heater 178 is shown as being located downstream of the cooler 180, in other forms, the heater 178 may be located upstream of the cooler 180 to increase the dry bulb temperature of the air before the cooler 180 condenses moisture in the air.

[0060] refer to Figure 8, the drift measurement sensor 150 may include additional sensors for monitoring other conditions of the air flowing through the drift measurement sensor 150. The drift measurement sensor 150 may include a carbon monoxide (CO) sensor 182, a carbon dioxide (CO2) sensor 184, and a volatile organic compound (VOC) sensor 186. These sensors may be installed in the channel 172 of the drift measurement sensor 150 to monitor the amount of carbon monoxide, carbon dioxide, and volatile organic compounds in the air. In the case where the drift measurement sensor 150 includes a heater 178 and / or a cooler 180, the CO sensor 182, the CO2 sensor 184, and the VOC sensor 186 may be installed in the channel 172 downstream of the heater 178 and / or the cooler 180. Similarly, other sensors may be included in the drift measurement sensor to measure the amount of other chemicals, bacteria, and / or organisms in the air.

[0061] refer to Fig. 9 , the drift measurement sensor 150 may include a filter 188. The filter 188 may be mounted at the inlet 174 of the drift measurement sensor 150 and allow air and drift particles to pass through while preventing debris and larger particles from flowing through the drift measurement sensor 150. For example, the filter 188 may prevent leaves, dust, and other such debris from entering the drift measurement sensor 150. Such debris may interfere with the measurement of the sensor within the channel 172 of the drift measurement sensor 150. In addition, such debris may clog the channel 172, which may hinder or restrict the airflow through the channel. For example, the filter 188 may include a mesh screen having a pore size in the range of about 1 mm to about 2 mm. The filter 188 may be a relatively coarse screen to prevent the entry of large particles and debris while reducing the interference of the filter 188 with particulate matter carried in the air entering the drift measurement sensor 150.

[0062] refer to Fig.10 , the drift measurement sensor 150 has an air sampling device 150A that includes a duct 170 and a damper 190 that cooperate to provide an air velocity in the duct 170 that corresponds to an air velocity outside the duct 170. The damper 190 can be mounted at the inlet 174 and can prevent debris (e.g., leaves) from entering the drift measurement sensor 150. The damper 190 helps prevent debris from entering the passage 172 and reaching the sensor, which could interfere with measurements made by the sensor and / or could block the passage 172. The damper 190 can also be adjusted to provide a specific air velocity through the passage 172.

[0063] The damper 190 can be pivoted to close or open the inlet 174 to prevent or allow air to flow through the drift measurement sensor 150. For example, the damper 190 can be closed when the drift measurement sensor 150 is not used or when it is raining. For example, the damper 190 can be pivoted by a motor, for example, in response to a control signal from the controller 162. Fig.11 In another embodiment, the drift measurement sensor 150 may include a damper 192 mounted at the outlet 176, in addition to or in place of the damper 190 at the inlet 174. The damper 192 may prevent debris from entering the drift measurement sensor 150 through the outlet 176, which may interfere with sensor measurements and / or block the passage 172. The damper 192 may be pivoted to close or open the outlet 176 to prevent or allow air to flow into or out of the drift measurement sensor 150 through the outlet 176. For example, the damper 192 may be closed when the drift measurement sensor 150 is not in use or when it is raining. For example, the damper 192 may be pivoted by a motor, for example, in response to a control signal from the controller 162. The damper 192 may be adjusted to provide a specific air velocity through the passage 172.

[0064] refer to Fig.12 , shows a drift measurement sensor 400, which is similar in many respects to the drift measurement sensor 150 discussed above, so the differences will be highlighted in the following discussion. The drift measurement sensor 400 can be installed at the air inlet 118 and / or the air outlet 130 of the cooling tower 100 to monitor the quality of the air when entering the cooling tower 100 and / or after leaving the cooling tower 100. The drift measurement sensor 400 includes a conduit, such as a tube 402, having a channel 404 extending from an inlet 406 to an outlet 408. As with the drift measurement sensor 150 described above, the drift measurement sensor 400 can similarly include a temperature sensor 420, a relative humidity sensor 422, and a particulate matter sensor 424.

[0065] The conduit 402 of the drift measurement sensor 400 may have a curved portion, such as an elbow 410, which changes the direction of air flow in the channel 404 as the air extends from the inlet 406 to the outlet 408. The elbow 410 changes the direction of the airflow in the conduit 402 and promotes isokinetic or similar air velocities within the channel 404 relative to the airflow of the cooling tower 100. Similar air velocities inside and outside the channel 404 ensure that all particle sizes in the airflow outside the drift measurement sensor 400 can enter the channel 404. In the example embodiment shown, the conduit 402 has a first portion 412 extending from the inlet 406 to the elbow 410 and a second portion 414 extending from the elbow 410 to the outlet 408. The first portion 412 and the second portion 414 extend transversely to each other. In one embodiment, the elbow 410 is a 90 degree elbow so that the air leaves the drift measurement sensor 400 in a direction substantially perpendicular to the direction in which the air enters the drift measurement sensor 400. Although a 90 degree elbow is shown, elbows of other angles may be used, including, for example, elbows of 10 to 89 degrees. Including elbow 410 in conduit 402 causes a portion of the air and drift to impact the side walls of channel 404 because elbow 410 is bent to direct the airflow in a different direction, such as toward outlet 408. As the air flows around elbow 410, the drift carried in the air is separated from the air due to inertial impact. In other words, as the air and drift flow around elbow 410, the air and drift impact the side walls of channel 404, causing the drift in the air to lose speed and / or accumulate on the side walls of channel 404. Therefore, elbow 410 removes some of the drift from the airflow, thereby reducing the amount of water droplets reaching sensors 420, 422, 424. As described above, water on the sensor can reduce the accuracy of the sensor data and / or can cause sensor failure. In one embodiment, the drift measurement sensor 400 is oriented with the first portion 412 vertically lower than the second portion 414 so that gravity pulls the drift collected at the elbow 410 downward and out of the tube 402 through the inlet 406 .

[0066] refer to Fig.13 In one embodiment, the drift measurement sensor 400 may include a heater 426 to heat and dry the air flowing through the passage 404 before the air flows through the sensors 420, 422, 424. The heater 426 may be installed downstream of the elbow 410 to dry the air after removing some of the water from the air flowing around the elbow 410 as described above.

[0067] refer to Fig.14, the drift measurement sensor 400 may include a cooler 428 to cool and condense moisture in the air. Thus, the cooler 428 may dry the air flowing through the passage 404 before the air flows through the sensors 420, 422, 424. The cooler 428 may be installed downstream of the elbow 410 to dry the air after removing some of the water from the air flowing around the elbow 410 as described above. Fig.15 , the drift measurement sensor 400 may include a heater 426 and a cooler 428 , which may be operated to heat and dry the air before the air flows through the sensors 420 , 422 , 424 .

[0068] refer to Fig.16 , the drift measurement sensor 400 may include additional sensors for monitoring other conditions of the air flowing through the drift measurement sensor 400. The drift measurement sensor 400 may include a CO sensor 430, a CO2 sensor 432, and a VOC sensor 434. These sensors may be installed in the channel 404 of the drift measurement sensor 400 to monitor the amount of carbon monoxide, carbon dioxide, and volatile organic compounds in the air. After removing some larger droplets from the airflow around the elbow 410, the CO sensor 430, the CO2 sensor 432, and the VOC sensor 434 may be installed downstream of the elbow 410. In the case where the drift measurement sensor 400 includes a heater 426 and / or a cooler 428, the CO sensor 430, the CO2 sensor 432, and the VOC sensor 434 may be installed in the channel 172 downstream of the heater 426 and / or the cooler 428. Similarly, other sensors may be included in the drift measurement sensor to measure air quality, such as the amount of other chemicals, bacteria, or organisms in the air.

[0069] refer to Fig.17 , the drift measurement sensor 400 may include a filter 436 mounted at the inlet 406 of the drift measurement sensor 400 to prevent debris from flowing into or through the drift measurement sensor 400, as described above with respect to the above embodiments. Fig.18 , the drift measurement sensor 400 may include a damper 438 mounted at the inlet 406 to selectively open or close the inlet 406 and / or prevent debris from flowing into or through the drift measurement sensor 400, as described above. Fig.19 The drift measurement sensor 400 may further include a damper 440 installed at the outlet 408 to selectively open or close the outlet 408 and / or prevent debris from flowing into the drift measurement sensor 400 through the outlet, as described with respect to the above embodiments.

[0070] refer to Fig. 20, the cooler 428 may include a drain pipe 442 to drain condensed water from the drift measurement sensor 400. For example, when air flows through the channel 404 of the conduit 402, the cooler 428 may be operated to condense moisture in the air. The condensed moisture may be collected and / or directed to the drain pipe 442 to remove moisture from the drift measurement sensor 400. The condensed moisture may flow through the channel 444 of the drain pipe 442 and away from the drift measurement sensor 400. For example, the condensed moisture may flow through the drain pipe 442 into the sump 132 of the cooling tower 100. The drift measurement sensor 400 may include a conductivity sensor 446 for measuring the conductivity of the liquid flowing through the drain pipe 442. In another embodiment, the drift measurement sensor 400 includes a pH sensor as a replacement or supplement for the conductivity sensor 446. Data from the drift measurement sensor 400 regarding the pH of water collected by the drift measurement sensor 400 may be used to determine abnormal changes in drift in a manner similar to the methods discussed herein for conductivity data and particulate matter data.

[0071] The controller 162 may receive conductivity data of the condensate from the conductivity sensor 446 and may use the conductivity data to evaluate the drift condition of the cooling tower 100. For example, the conductivity of the condensate of the drift measurement sensor 400 installed at the air outlet 130 of the cooling tower 100 may be compared to the conductivity of the condensate of the drift measurement sensor 400 installed at the air inlet 118. As another example, the conductivity of the condensate may be compared to the conductivity of the fluid in the sump 132 to detect whether the drift rate of the cooling tower 100 is increasing. In one example where drift is not occurring, the conductivity of the liquid collected in the drift measurement sensor 400 may be approximately 0 μS / cm. In the case where the amount of drift in the cooling tower 100 is normal or acceptable, a portion of the liquid collected by the drift measurement sensor 400 may be drifting, which will increase the conductivity of the liquid collected by the drift measurement sensor 400. For example, where the conductivity of the fluid in the basin is 1500 μS / cm and the drift rate is a normal amount of about 0.005%, the conductivity of the liquid collected by the drift measurement sensor 400 may be about 50 μS / cm. Where the drift amount is abnormally high, a larger portion of the liquid collected by the drift measurement sensor 400 is drifting, which further increases the conductivity of the collected liquid. Continuing with the above example, where the conductivity of the fluid in the basin is 1500 μS / cm and the drift rate is high at about 0.015%, the conductivity of the liquid collected by the drift measurement sensor 400 may be about 150 μS / cm. The controller 162 may determine that the drift rate is high based on the conductivity of the liquid collected by the drift measurement sensor 400, for example, the conductivity of the collected liquid is outside the expected range of normal drift rates, for example, the range of 50 μS / cm + / - 25 μS / cm.

[0072] refer to Fig.21 , the drift measurement sensor 400 may include a cooler 428 , which may be used to condense and sample the condensate, instead of the temperature sensor 420 , the relative humidity sensor 422 , and / or the particulate matter sensor 424 .

[0073] refer to Fig. 22 , shows a drift measurement sensor 500 according to another embodiment, which is similar to the drift measurement sensor discussed above in many aspects, so the differences will be highlighted in the following discussion. The drift measurement sensor 500 has a conduit 502, which defines a channel 504. The conduit 502 includes a first elbow 505 and a second elbow 507. Air and drift enter the conduit 502 through an inlet 506 and flow through a straight pipe portion 508 of the channel 504 to reach the first elbow 505. The first elbow 505 is a U-shaped elbow, which is bent about 180 degrees. When the air flows around the first elbow 505, due to the inertial impact as described above, the drift carried in the air is separated from the air when the air flows around the elbow 505. The air and the remaining drift flow from the first elbow 505 to the second elbow 507, where the drift can be further separated from the air by inertial impact. The second elbow 507 is a U-shaped elbow, which is bent about 180 degrees. The drift removed from the air by redirecting the air at the first elbow 505 and the second elbow 507 can be collected in the second elbow 507 for testing and / or removal from the drift measurement sensor 500. The second elbow 507 can be oriented so that the center portion 510 of the second elbow 507 is vertically lower than the end portions 512, 514 of the elbow 507 to help collect the separated drift due to gravity. The air and any remaining drift in the air flows from the second elbow 507 through the straight pipe portion 516 to the outlet 518.

[0074] A drain pipe 520 may be mounted to the conduit 502 at the second elbow 507 to drain the accumulated drift (e.g., water and particulate matter) from the drift measurement sensor 500, as described above. The drain pipe 520 may be mounted at the center portion 510, for example, at the vertical lowest point, so that the accumulated drift is collected and directed into the drain pipe 520. A conductivity sensor 522 may be mounted to the drain pipe 520 to measure the conductivity of the accumulated drift flowing through the drain pipe 520. The conductivity of the accumulated drift may be used to determine the amount of particles in the air, for example, the amount of particles removed due to inertial impact when the air and drift flow around the first elbow 504 and the second elbow 507.

[0075] In one embodiment, Fig. 22The drift measurement sensor 500 of the other figures includes a dehumidifier 513 to increase the collection of water. The water collected by the dehumidifier is drift water, which can make the analysis of the collected water more accurate than mixing the water with water condensed from the ambient air. The dehumidifier can include, for example, a cooler, a heater and cooler combination, and / or a vapor permeable membrane.

[0076] refer to Fig.23 In one embodiment, the drift measurement sensor 500 includes a temperature sensor 524, a relative humidity sensor 526, and a particulate matter sensor 528 for monitoring other aspects of the air flowing through the drift measurement sensor 500. The temperature sensor 524, the relative humidity sensor 526, and the particulate matter sensor 528 can be installed in a portion of the conduit 502 so that the drift is in contact with the air after being separated from the air at the first elbow 504 and / or the second elbow 507. Other sensors can also communicate with the channel 504 of the drift measurement sensor 500, including, for example, a CO sensor, a CO2 sensor, and / or a VOC sensor. The sensor can be installed in the straight pipe section 516 of the conduit, downstream of the second elbow 507.

[0077] refer to Fig.24 , shows a drift measurement sensor 600 according to another embodiment, which is similar in many respects to the drift measurement sensors of other embodiments discussed above, so the differences will be highlighted in the following discussion. The drift measurement sensor 600 includes an air sampling device having a body (e.g., a conduit 602) having an interior or channel 604 through which air and drift can flow. The conduit 602 may include a sidewall extending around the channel 604. The conduit 602 includes one or more inlet openings 606 and an outlet 608. Air and drift can enter the conduit 602 through the inlet opening 606 and flow along the channel 604 to the outlet 608. The inlet opening 606 can be a through opening formed in the sidewall of the conduit 602 so that air enters the conduit 602 substantially perpendicular to the central axis 607 of the channel 604. When the airflow changes direction to flow along the channel 604, the inertial impact of the air on the inner surface portion 609 can cause some of the drift to separate from the air.

[0078] Fig.24The air sampling device of the drift measurement sensor 600 includes a fan assembly 610 having a motor 612 that rotates a fan 614. The fan assembly 610 can be mounted at the end of the duct 602 near the outlet 608. The fan assembly 610 is operable to move air from the inlet opening 606 to the outlet 608 through the duct 602. The operation of the fan assembly 610 can draw air and drift into the duct 602 through the inlet opening 606 and exhaust the air from the duct 602 through the outlet 608. Operating the fan assembly 610 can help ensure that a representative sample of the air flowing through the drift measurement sensor 600 flows through the channel 604 of the drift measurement sensor 600 to monitor the quality of the air. For example, the fan assembly 610 can be operated to achieve a constant air flow rate through the drift measurement sensor 600, thereby providing a more uniform drift measurement at all fan speeds of the associated heat exchange device. The fan assembly 610 can be operated to move air through the drift measurement sensor 600 at approximately the same speed as the air flowing through the cooling tower around the drift measurement sensor 600. The drift measurement sensor 600 (e.g., a controller of the drift measurement sensor 600) can receive a signal indicating the airflow speed around the drift measurement sensor and increase, decrease, or maintain the speed of the fan assembly 610 to match the airflow speed in the drift measurement sensor 600 with the airflow speed outside the drift measurement sensor 600 in the cooling tower. For example, the drift measurement sensor 600 can include an air speed sensor 619 mounted to a duct to measure the airflow speed outside the drift measurement sensor 600. As another example, the cooling tower includes an air speed sensor located inside, at an inlet, or at an outlet of the cooling tower, and the controller of the cooling tower transmits the air speed data to the drift measurement sensor 600. In some forms, the drift measurement sensor 600 receives an operating variable (e.g., electrical power or current provided to the fan assembly, or the speed of the fan assembly) from the fan assembly 102 of the cooling tower, the operating variable indicating the airflow speed through the cooling tower. It should be understood that other embodiments of drift measurement sensors discussed herein that include fan assemblies may operate similarly to drift measurement sensor 600 .

[0079] The drift measurement sensor 600 includes a temperature sensor 616, a relative humidity sensor 618, and a particulate matter sensor 620 mounted in the passage 604 between the inlet opening 606 and the outlet 608. The temperature sensor 616, the relative humidity sensor 618, and the particulate matter sensor 620 may be used to assess the condition of the air flowing through the duct 602, which may be used to determine if the drift rate of the cooling tower 100 is increasing, as described above.

[0080] refer to Fig.25, the drift measurement sensor 600 may include a heater 622. The heater 622 may be positioned within the passage 604 between the inlet opening 606 and the sensor. The heater 622 may be operable to increase the temperature of the air and / or dry the air, as discussed above with respect to other embodiments, to reduce or remove water droplets in the air, thereby preventing water from accumulating on the sensor and interfering with the measurement.

[0081] refer to Fig.26 , the drift measurement sensor 600 can include a cooler 624. The cooler 624 can be positioned within the channel 604 between the inlet opening 606 and the sensor. The cooler 624 can be operated to dehumidify the air, as discussed above for other embodiments. The cooler 624 can condense moisture in the air and drift, which can prevent moisture or water from accumulating on the sensor and interfering with the measurement.

[0082] refer to Fig. 27 , the drift measurement sensor 600 may include a heater 622 and a cooler 624. The heater 622 and the cooler 624 may be mounted within the passage 604 between the inlet opening 606 and the sensor. The heater 622 and the cooler 624 may be operable to dry water droplets in the air and / or dehumidify the air upstream of the sensor, as discussed above with respect to other embodiments.

[0083] refer to Fig.28 In one embodiment, the drift measurement sensor 600 includes additional sensors for measuring and monitoring other conditions of the air flowing through the drift measurement sensor 600. The drift measurement sensor 600 may include a carbon monoxide (CO) sensor 626, a carbon dioxide (CO2) sensor 628, and a volatile organic compound (VOC) sensor 630. These sensors may be installed in the channel 604 of the drift measurement sensor 600 to monitor the amount of carbon monoxide, carbon dioxide, and volatile organic compounds in the air. In the case where the drift measurement sensor 600 includes a heater 622 and / or a cooler 624, the CO sensor 626, the CO2 sensor 628, and the VOC sensor 630 may be installed in the channel 604 downstream of the heater 622 and / or the cooler 624. Similarly, other sensors may be included in the drift measurement sensor to measure the amount of other chemicals, bacteria, or organisms in the air.

[0084] refer to Fig.29 In one embodiment, the drift measurement sensor 600 includes a filter 632 at the inlet opening 606. The filter 632 can prevent debris and large particles (relative to drift particles) from entering the drift measurement sensor 600. The filter 632 can be, for example, a mesh screen.

[0085] refer to Fig.30, the drift measurement sensor 600 may include a damper 634 at the inlet opening 606. The damper 634 may be pivoted to selectively open or close the inlet opening 606 and / or prevent debris (eg, leaves) from entering the drift measurement sensor 600, as described above with respect to other embodiments. Fig.31 , the drift measurement sensor 600 may further include a damper 636 mounted at the outlet 608. The damper 636 may pivot to selectively open or close the outlet 608 and / or prevent debris from entering the drift measurement sensor 600 through the outlet 608, as described above with respect to other embodiments.

[0086] refer to Fig.32 and Fig.33 , the drift measurement sensor 600 may include a cooler 624 having (see Fig.32 ) or not (see Fig.33 ) temperature sensor 616, relative humidity sensor 618, and / or particulate matter sensor 620. Cooler 624 may include a drain 638 through which moisture condensed from the air flowing through the drift measurement sensor 600 may be removed from the drift measurement sensor 600, as described above. Cooler 624 may collect the condensed water and direct the moisture to the drain 638. Drift measurement sensor 600 may include a conductivity sensor 641 for measuring the conductivity of the condensed water flowing through the drain 638, as described above. In one embodiment where the drift measurement sensor 600 includes a temperature sensor 616 and a relative humidity sensor 618, the temperature sensor 616 and the relative humidity sensor 618 may be used to control the operation of cooler 624. For example, the temperature and humidity measurements may be used to determine the amount of cooling provided by cooler 624 for condensing moisture in the air. Alternatively or additionally, temperature sensor 616, relative humidity sensor 618, and / or particulate matter sensor 620 may be used to monitor drift as described above.

[0087] refer to Fig.34In one embodiment, the conduit 602 of the drift measurement sensor 600 may include an elbow 640 for separating the drift from the inertial impact of the air as described above. The elbow 640 may be a substantially U-shaped elbow between the inlet 606 and the outlet 608. When the air flows through the elbow 640 along the channel 604, the drift may impact the inner surface portion of the conduit 602 and gather on the inner surface portion. The drift may flow along the sidewall of the elbow 640 and collect in the elbow 640. For example, the central portion 642 of the elbow 640 may be vertically positioned at a lower position than the inlet portion 644 and the outlet portion 646 of the elbow 640, so that the drift flows along the inner surface portion of the conduit 602 to the central portion 642 of the elbow 640 due to gravity. The drift measurement sensor 600 may include a discharge pipe 648 connected to the elbow 640, for example, at the lowest point of the elbow 640 where the drift gathers or collects. The drift flows through the drain pipe 648 and is removed from the drift measurement sensor 600. The drift measurement sensor 600 may include a conductivity sensor 641 for measuring the conductivity of the condensed water flowing through the drain pipe 648, as described above. In another embodiment, the drift measurement sensor 600 has a liquid flow sensor instead of or in addition to the conductivity sensor 641. The controller 162 may determine changes in the amount of drift in the cooling tower using data from the liquid flow sensor.

[0088] refer to Fig.35 , the drift measurement sensor 600 may also include a temperature sensor 616, a relative humidity sensor 618, and / or a particulate matter sensor 620 positioned after the elbow 640, wherein at least a portion of the drift has been removed from the air by the elbow 640, as described above.

[0089] refer to Fig.36A According to another embodiment, a heat exchange device 700 is provided. The heat exchange device 700 can be operated as a fluid cooler (e.g., a closed circuit cooling tower) or an evaporative condenser (as some examples). The heat exchange device 700 is similar in many respects to the above-mentioned Figure 1A The heat exchange device 700 is similar to the cooling tower 100 of FIG. 1 , and therefore the differences will be highlighted in the following discussion. The heat exchange device 700 includes an airflow generator (eg, fan assembly 702 ), an indirect heat exchanger 704 , and an evaporative liquid distribution system 706 for distributing a liquid (eg, water) to the indirect heat exchanger 704 .

[0090] The indirect heat exchangers 704 each include an inlet header 705 for receiving a fluid, an outlet header 707, and a heat exchange element 715, such as a pillow plate heat exchanger 717, for connecting the inlet header 705 and the outlet header 707. In other embodiments, a different heat exchange element 715 may be used in place of or in addition to the pillow plate heat exchanger 717, such as a coil, a plate heat exchanger, and / or a fin tube heat exchanger. The fluid enters the inlet header 705, travels through the pillow plate heat exchanger 717, gathers at the outlet header 707, and then flows out of the indirect heat exchanger 704. The fluid received at the inlet header 705 may include, for example, liquid water, water vapor (e.g., steam), a mixture of liquid water and water vapor, ammonia, brine, and / or glycol (e.g., propylene, ethylene). In one embodiment, the fluid received by the inlet header 705 can include a refrigerant such as R-134a, R410, R404, and / or R744. In some embodiments, the positions of the inlet header 705 and the outlet header 707 can be reversed, with the outlet header 707 located above the inlet header 705.

[0091] In embodiments where the heat exchange element 715 includes one or more coils, each coil may have a plurality of flow channels located intermediate the inlet header 705 and the outlet header 707. In one embodiment, the coil includes one or more tubes, each having an interior that allows fluid to travel therethrough and a sidewall extending around the interior. The coil may have a variety of configurations, such as straight tubes extending between headers or serpentine tubes having straight flow channels connected by elbows. The coil may or may not include fins.

[0092] Rotation of the fan of the fan assembly 702 causes air to move from the air inlet 711, through the filter 709, across the pillow plate heat exchanger 717, through the drift eliminator 734, up through the fan assembly 702, and out of the air outlet 713 of the heat exchange device 700. In one approach, the fluid in the pillow plate heat exchanger 717 has a higher temperature than the air flowing through the pillow plate heat exchanger 717, so that heat is transferred from the higher temperature fluid inside the pillow plate heat exchanger 717 to the cooler air flow moving past the outside of the pillow plate heat exchanger 717 through the tube side walls of the pillow plate heat exchanger 717.

[0093] The evaporative liquid distribution system 706 includes a liquid supply valve connected to a liquid source. The liquid utilized by the evaporative liquid distribution system 706 may include, for example, water (e.g., tap water, rainwater, and / or non-potable water). In some embodiments, the liquid distribution system 706 receives water from a water treatment system that converts raw water into treated water having properties and / or additives (e.g., antifungal, antimicrobial) suitable for distribution to the heat exchange device 700. In one embodiment, the liquid supply valve includes a replenishment valve 716 that can be opened to distribute liquid to the sump 720 of the heat exchange device 700. When the sump 720 is empty or when the liquid level in the sump 720 is low, the replenishment valve 716 can be opened to distribute liquid to the sump 720, and / or introduce fresh liquid into the heat exchange device 700.

[0094] The evaporative liquid distribution system 706 includes a pump 722, a conduit 718, and a nozzle 714. The pump 722 pumps liquid from the sump 720 through the conduit 718 to the nozzle 714 positioned above the pillow plate heat exchanger 717 of the indirect heat exchanger 704. The pump 722 can be operated to distribute liquid from the sump 720 to the pillow plate heat exchanger 717 to help cool the fluid flowing through the pillow plate heat exchanger 717. The evaporative liquid absorbs heat from the pillow plate heat exchanger 717 to remove heat from the pillow plate heat exchanger 717. In addition, a portion of the evaporative liquid evaporates, which further removes heat from the pillow plate heat exchanger 717. The unevaporated liquid falls back to the sump 720.

[0095] Thus, the liquid distribution system 706 can operate in conjunction with the fan assembly 702 to help remove heat from the fluid flowing through the pillow plate heat exchanger 717. For example, the heat exchange device 700 can have a dry mode in which the controller 162 operates the fan assembly 702 to generate airflow through the pillow plate heat exchanger 717 without operating the pump 722. The controller 162 can determine that the heat exchange device 700 in dry mode cannot meet the return fluid set point requested by the HVAC controller (for example). The controller 162 can reconfigure the heat exchange device 700 to a wet mode to meet the return fluid set point. As another example, the controller 162 can reconfigure the heat exchange device 700 to operate in a wet mode to save power or when it is more cost-effective to operate the heat exchange device 700 in a wet mode.

[0096] In wet mode, controller 162 operates pump 722 to spray evaporated liquid from sump 720 onto pillow plate heat exchanger 717. Heat exchange device 700 may include flow meter 726 and temperature sensor 728 attached to conduit 718 for monitoring the flow and temperature of liquid distributed on pillow plate heat exchanger 717.

[0097] The heat exchange device 700 may include a temperature sensor 730 and a conductivity sensor 732 for the sump 720 to monitor the temperature and conductivity of the fluid in the sump 720. The controller 162 may receive data from the temperature sensor 730 and / or the conductivity sensor 732. The sump 720 may have a drain valve 724 that may be opened (e.g., by the controller 162) to drain the fluid from the sump 720 and out of the circulation within the heat exchange device 700. For example, when there is too much liquid in the sump 720, the drain valve 724 may be opened to drain the liquid from the sump 720, or, for example, when the conductivity or pH value of the liquid exceeds a threshold, as part of a liquid switching process, the liquid may be completely drained from the sump 720.

[0098] As part of the fail-safe operation of heat exchange device 700, drain valve 724 can also be opened to drain liquid from sump 720. For example, if controller 162 detects an abnormal change in the drift of heat exchange device 700 and controller 162 detects an increased risk of bacterial contamination, controller 162 can open drain valve 724 and notify maintenance workers of the problem. Controller 162 can monitor whether the liquid in sump 720 is at risk of bacterial contamination using water sample analysis and / or biofilm sensors.

[0099] The heat exchange device 700 may include one or more drift measurement sensors 150 according to the above-described embodiments to monitor one or more variables of the cooling tower 100, such as variables related to air quality conditions. Fig.36A As shown, the heat exchange device 700 may include a drift measurement sensor 150 at an outlet 713 and one or two inlets 711 of the heat exchange device 700. As discussed in more detail above, the drift measurement sensor 150 includes a sensor for monitoring a variable indicating drift. The controller 162 may monitor changes in the monitored variable and determine whether the change indicates that the drift rate of the cooling tower has increased by more than an expected or acceptable amount. For example, when the liquid distribution system 706 is turned on, the controller 162 will expect an increase in the amount of particulate matter detected by the drift measurement sensor 150 downstream of the pillow plate heat exchanger 717 at the outlet 713. The controller 162 may monitor the increase in particulate matter at the outlet 713 and determine whether the increase in particulate matter exceeds an expected or acceptable amount. If the increase in particulate matter exceeds an acceptable amount (e.g., a predetermined error margin exceeding an upper threshold), the controller 162 determines that the drift rate of the heat exchange device 700 has increased significantly.

[0100] Drift measurement sensors 150 may be positioned at various locations of the heat exchange device 700 to monitor drift. Fig.36B, an alternative configuration of a heat exchange device 700 is provided in which the drift measurement sensor 150 is mounted downstream of the indirect heat exchanger 704 and upstream of the fan assembly 702 .

[0101] The controller 162 may compare air variables detected at the air inlet 711 upstream of the indirect heat exchanger 704 with air variables detected downstream of the indirect heat exchanger 704 after the drift eliminator 734 to determine a drift condition using the techniques discussed above. Figure 3A , the controller 162 can determine that the heat exchange device 700 has an unacceptable drift condition based on the speed of the fan assembly 102, the water spray status (e.g., whether the pump 722 is operating), the conductivity of the liquid in the sump 720, and the air variables (e.g., particulate matter, relative humidity, and dry-bulb temperature) detected by the drift measurement sensors 150 at the air inlet 711 and the air outlet 713 of the heat exchange device 700.

[0102] refer to Fig.37A According to another embodiment, a cooling tower 800 is provided. The cooling tower 800 is similar in many respects to the cooling tower discussed above, so the differences will be highlighted in the following discussion. The cooling tower 800 includes an airflow generator (e.g., a fan assembly 802), an indirect heat exchanger 804, a liquid distribution system 806, and an adiabatic precooler system 803. The adiabatic precooler system 803 includes: a liquid absorbing material (e.g., one or more insulation pads 808); and, an evaporative liquid distribution system 806 for distributing a liquid (e.g., water) onto the insulation pad 808 upstream of the indirect heat exchanger 804.

[0103] The fan assembly 802 includes a fan 810 and a motor 812 that rotates the fan 810 to generate an airflow along a path 809 relative to the housing 801 of the cooling tower 800. Specifically, the fan assembly 802 draws air into the air inlet 811 of the housing 801; through the insulation pad 808; and from the insulation pad 808 to the indirect heat exchanger 804. The insulation pad 808 can be made of any liquid absorbing material that allows air to flow through, including, for example, cellulose and / or impregnated cellulose fibers. As another example, the liquid absorbing material can include inorganic impregnated glass fibers. As yet another example, the insulation pad 808 can be an adiabatic precooler and include a microporous membrane that allows liquid water to penetrate through the membrane. The drift sensor 150 downstream of the insulation pad 808 can detect droplets entrained by the airflow through the membrane.

[0104] Each indirect heat exchanger 804 includes: an inlet header 805 for receiving a fluid; an outlet header 807; and a heat exchange element (e.g., a fin-tube heat exchanger 817) for connecting the inlet header 805 and the outlet header 807. Other heat exchange elements may be used, such as microtubes, serpentine tubes, plate heat exchangers, etc. The fluid enters the inlet header 805; travels through the fin-tube heat exchanger 817; and gathers at the outlet header 807, and then flows out of the indirect heat exchanger 804. The fluid received at the inlet header 805 may include, for example, liquid water, water vapor (e.g., steam), a mixture of liquid water and water vapor, ammonia, brine, and / or glycol (e.g., propylene, ethylene). In one embodiment, the fluid received by the inlet header 805 may include a refrigerant, such as R-134a, R410, R404, and / or R744.

[0105] The rotation of the fan 810 causes air to move from the air inlet 811, through the insulation pad 808, through the fin-tube heat exchanger 817, up through the fan assembly 802, and out of the heat exchange device 800 through the air outlet 813. In one approach, the fluid in the fin-tube heat exchanger 817 has a higher temperature than the air flowing through the fin-tube heat exchanger 817, so that heat is transferred through the fin-tube heat exchanger 817 from the higher temperature fluid inside the fin-tube heat exchanger 817 to the cooler air flow flowing outside the fin-tube heat exchanger 817.

[0106] The evaporative liquid distribution system 806 includes a liquid supply valve connected to a liquid source. The liquid utilized by the liquid distribution system 806 can be, for example, water (e.g., tap water, rainwater, and / or non-potable water). In some embodiments, the liquid distribution system receives water from a water treatment system that converts raw water into treated water having properties and / or additives (e.g., antifungal, antimicrobial) suitable for use in the heat exchange device 800. In one embodiment, the liquid supply valve includes a make-up valve 816 that can be opened to distribute liquid into a sump 820 of the cooling tower 800.

[0107] The evaporative liquid distribution system 806 also includes a pump 822 within the sump 820. The pump 822 is operable to pump liquid from the sump 820 through the conduit 818 to one or more outlets of the evaporative liquid distribution system 806, such as the nozzle 814. The nozzle 814 directs the liquid onto the insulating pad 808. The controller 162 can control the pump 822 to cause the evaporative liquid distribution system 806 to distribute the liquid onto the insulating pad 808 to improve the efficiency of the indirect heat exchanger process. For example, the insulating pad 808 is positioned in the flow path of the air upstream of the fin-tube heat exchanger 817. When the insulating pad 808 is soaked with liquid from the liquid distribution system 806, the liquid in the insulating pad 808 evaporates into the air passing through the pad 808, which reduces the temperature of the air before the air passes through the fin-tube heat exchanger 817. The cooler air passing through the fin-tube heat exchanger 817 improves the efficiency of the indirect heat exchange process. Liquid that is not absorbed by the insulation pad 808 may be collected in a sump 820 positioned below the insulation pad 808 .

[0108] The cooling tower 800 may include a temperature sensor 830 and a conductivity sensor 832 associated with the sump 820 for monitoring the temperature and conductivity of the fluid within the sump 820. The controller 162 may receive data from the temperature sensor 830 and / or the conductivity sensor 832. The sump 820 may have a drain valve 824 that may be opened (e.g., by the controller 162) to drain the fluid from the sump 820 and out of the circulation within the cooling tower 800. For example, the drain valve 824 may be opened to drain the liquid from the sump 820 when there is too much liquid in the sump 820, or, for example, when the conductivity or pH value of the liquid exceeds a threshold, as part of a liquid switching process, the liquid may be drained from the sump 820.

[0109] The cooling tower 800 may include one or more drift measurement sensors 150 according to the above-described embodiments to monitor one or more variables of the cooling tower 800, such as variables related to air quality conditions. Fig.37AAs shown, the cooling tower 800 may include a drift measurement sensor 150 at an outlet 813 and one or more inlets 811 of the cooling tower 800. As discussed in more detail above, the drift measurement sensor 150 includes one or more sensors to monitor one or more variables indicating the characteristics of the airflow received at the drift measurement sensor 150. The controller 162 may monitor changes in the monitored variables and determine whether the changes indicate that the drift rate of the cooling tower has increased by more than an expected or acceptable amount. For example, when the evaporative liquid distribution system 806 is turned on and the pump 822 begins to pump fluid, the controller 162 will expect an increase in the amount of particulate matter detected by the drift measurement sensor 150, for example, downstream of the fin-tube heat exchanger 817 at the outlet 813. The controller 162 may monitor the increase in particulate matter at the outlet 813 and determine whether the increase in particulate matter exceeds an expected or acceptable amount, so that the controller 162 determines that the heat exchange device 800 has an undesirable or unacceptable drift condition. The controller 162 can determine that there is no drift when the heat exchange device 800 is operating in a dry mode, in which the liquid distribution system 806 has been closed for a period of time (e.g., the insulation pad 808 is dry) because no evaporated liquid particles are carried away in the air flow toward the outlet 813.

[0110] The drift measurement sensor 150 may be installed at various locations of the heat exchange device 800 to monitor the drift. Fig.37B , the heat exchange device 800 includes a drift measurement sensor 150 installed downstream of the insulation pad 808 and upstream of the indirect heat exchanger 804. The controller 162 can compare the changes in air variables as the air passes through the insulation pad 808. In addition, because the drift measurement sensor 150 is immediately downstream of the insulation pad 808, the drift measurement sensor 150 is positioned to detect drift from the insulation pad 808 when the drift contacts the fin-tube heat exchanger 817. Positioning the drift measurement sensor 150 between the insulation pad 808 and the fin-tube heat exchanger 817 can also more accurately determine the magnitude of the increase in drift. The controller 162 can be programmed to adjust the operation of the heat exchange device 800 to resolve unacceptable drift conditions and limit fouling, scaling and / or corrosion.

[0111] In some embodiments, a drift measurement sensor for a heat exchange device may include a sensor configured to detect microorganisms, instead of or in addition to conductivity measurement. The microorganisms may include, for example, fungi, algae, and bacteria. The sensor may detect, for example, specific microorganisms and / or total bacteria in a sample. The controller of the heat exchange device may use bacteria detection to determine the occurrence of drift with an undesirable microbial content, for example, a drift containing an amount of microorganisms above a predetermined threshold. The drift measurement sensor may be cleaned regularly using manual or automatic methods, such as injecting chlorine, ultraviolet treatment, and / or flushing with water. The drift measurement sensor may also inactivate or kill detected bacteria after measurement, such as an online installed ultraviolet treatment system for treating the collected water and then returning the water to the sump of the device.

[0112] In some embodiments, the airflow generator of the air contactor includes a housing or other structure of the air contactor that generates the airflow. For example, the hyperbolic housing of a natural draft cooling tower has a shape that cooperates with the heated rising air in the cooling tower, draws air into the cooling tower and directs the heated air upward away from the cooling tower.

[0113] As another example, some air contactors include nozzles that spray liquid, and the spraying of the liquid causes the movement of air. The air contactor has a housing or other structure that guides the moving air into an airflow through the air contactor. In some embodiments, the air contactor does not include a fan.

[0114] refer to Fig.38 , a drift measurement sensor 900 is provided, which includes a body, such as a main conduit 902 having an inlet 904 (for receiving air) and an outlet 906. The drift measurement sensor 900 includes one or more sensors, such as a particle sensor 908, a relative humidity sensor 910, and a temperature sensor 912, which are configured to detect variables related to the air traveling through the main conduit 902. The drift measurement sensor 900 also includes a dehumidifier, such as a cooler 914, which removes moisture from the air and directs the collected water into a guiding conduit 916. The guiding conduit 916 has a collection portion, such as a U-shaped elbow 918, for collecting water, and a bacteria sensor 920 for detecting one or more variables related to bacteria in the water in the elbow 918.

[0115] refer to Fig.39 In another embodiment, a drift measurement sensor 900 is provided, wherein the drift measurement sensor 900 includes a conductivity sensor 922. In addition to the bacteria sensor 920 detecting one or more variables of bacteria in the water in the elbow 918, the conductivity sensor 922 is also configured to detect the conductivity of the water in the elbow 918.

[0116] Various other configurations of the drift measurement sensor 900 may be provided. For example, Fig.40 One embodiment of a drift measurement sensor 900 is shown, wherein the drift measurement sensor 900 includes a bacteria sensor 920 but does not include a particulate matter sensor 908 , a relative humidity sensor 910 , and a temperature sensor 912 . Fig.41 The embodiment adds a conductivity sensor 922.

[0117] refer to Fig.42 , a drift measurement sensor 1000 is provided, which includes a body 1002 having an inlet 1004 for receiving air, an outlet 1006, and a collection portion in which drift in the air can be collected, such as an elbow 1008. The drift measurement sensor 1000 has a conduit 1010, which guides the collected drift to a bacteria sensor 1012. The drift measurement sensor 1000 also includes a particle sensor 1014, a relative humidity sensor 1016, and a temperature sensor 1018. In another embodiment, the drift measurement sensor 1000 can be provided with a conductivity sensor 1020, such as Fig.43 shown.

[0118] In yet another embodiment, the drift measurement sensor 1000 may not be provided with the particle sensor 1014, the relative humidity sensor 1016, and the temperature sensor 1018. Fig.44 Similarly, the drift measurement sensor can be provided with a bacteria sensor 1012 and a conductivity sensor 1020, as shown in FIG. Fig.45 shown.

[0119] refer to Fig.46 , a drift measurement sensor 1100 is provided, which includes a body 1102, an inlet opening 1104, an outlet 1106, and a fan assembly 1108 for generating an airflow through the body 1102. The drift measurement sensor 1100 has a particle sensor 1110, a relative humidity sensor 1112, and a temperature sensor 1114. The drift measurement sensor 1100 has a dehumidifier (e.g., a cooler 1116) for removing moisture from the air and a conduit 1118 configured to guide the collected water to a bacteria sensor 1120. In another embodiment, the drift measurement sensor 1100 has a conductivity sensor 1122, such as Fig.47 shown.

[0120] In yet another embodiment, the drift measurement sensor 1100 is not provided with the particle sensor 1110, the relative humidity sensor 1112, and the temperature sensor 1114. Fig.48 The drift measurement sensor 1100 may be provided with a bacteria sensor 1120 and a conductivity sensor 1122, as shown in FIG. Fig.49 shown.

[0121] refer to Fig.50 , a drift measurement sensor 1200 is provided, which is similar to Fig.35 The drift measurement sensor 1200 includes a body 1202 having an air inlet 1204, an outlet 1206, a fan assembly 1208, and a collection portion (e.g., elbow 1210) for collecting water (e.g., drift) in the air traveling through the body 1202. The drift measurement sensor 1200 has a conduit 1212 that guides the collected water to a bacteria sensor 1214. The drift measurement sensor 1200 also includes a particle sensor 1216, a relative humidity sensor 1218, and a temperature sensor 1220. In one embodiment, the drift measurement sensor 1200 is provided with a conductivity sensor 1222, such as Fig.51 shown.

[0122] The drift measurement sensor 1200 may not be provided with the particle sensor 1216, the relative humidity sensor 1218 and the temperature sensor 1220. Fig.52 The drift measurement sensor 1200 may include a conductivity sensor 1222, such as Fig.53 shown.

[0123] refer to Fig.54 , provides another embodiment of the drift measurement sensor 150, which is similar to Fig.11 The embodiment shown. Fig.11 and Fig.54 One difference between the drift measurement sensors 150 is that Fig.54 The drift measurement sensor 150 has a damper 192 installed at the outlet 176 and no damper at the inlet 174.

[0124] refer to Fig.55 , provides another embodiment of a drift measurement sensor 150 that is similar in many respects to Figure 4 The embodiments shown are similar, so the differences are highlighted. Fig.55In the embodiment of the present invention, the tube 170 of the drift measurement sensor 150 has a large diameter portion 170B, a small diameter portion 170A, and a neck portion 170C connecting the large diameter portion 170B and the small diameter portion 170A. The large diameter portion 170B includes an air inlet 174. The neck portion 170C sends the air and drift in the large diameter portion 170B into the small diameter portion 170A. The sensors 152, 154, 156 detect variables (such as particulate matter, relative humidity, and temperature) of the air flow in the small diameter portion 170A. The diameter ratio of the large diameter portion 170B and the small diameter portion 170A and the shape of the neck portion 170C can be selected so that the air flowing through the small diameter portion 170A has the same speed as the air flow outside the tube 170.

[0125] refer to Figures 56A to 56E , provides an example graph including data showing how changing conditions of the cooling tower 100 may be used to detect changes in the drift rate of the cooling tower 100, similar to the above discussion FIG. 3A to FIG. 3F of charts. Figures 56A to 56E The graph of has additional columns for the spray flow 1302 of the liquid distribution system 106, the drift volume 1304 and the drift rate 1306 of the cooling tower 100. The spray flow 1302 and the drift volume 1304 can be in gallons per minute (gpm), while the drift rate 1306 is a dimensionless quantity, such as a percentage.

[0126] The drift rate 1306 is calculated by dividing the drift volume 1304 by the spray flow rate 1302 and then multiplying by 100. In other words, the drift rate 1306 is the percentage of spray from the liquid distribution system 106 that leaves the cooling tower 100 as drift. FIG. 56A to FIG. 56C , the controller 162 can calculate the drift rate 1306 based on the data collected by the sensors of the cooling tower 100. The controller 162 can determine whether the drift rate 1306 of the cooling tower is normal or abnormal by comparing the change in the drift rate 1306 from the baseline condition to the new condition. For example and with reference to Fig.56A , when the cooling tower 100 changes from the baseline condition to the new condition 2, the controller 162 can determine that the abnormal drift rate 1306 is because the drift rate 1306 doubles, that is, changes from 0.003% to 0.006%. The threshold change that triggers the determination of an abnormal drift condition can be fixed or variable, for example, when a specific change occurs in the operating conditions of the cooling tower 100, the drift rate increases by 25%. In contrast, when the cooling tower 100 changes from the baseline condition to the new condition 2, the controller 162 can determine that the normal drift rate 1306 is because the drift rate 1306 remains unchanged (0.003%).

[0127] Alternatively or additionally, the controller 162 may determine whether the drift rate 1306 is normal or abnormal by comparing the drift rate 1306 under a given condition with a threshold drift rate (e.g., 0.005%). For example, when the drift rate 1306 under a given condition is equal to or less than 0.005%, the drift variation between the air inlet and the air outlet of the cooling tower 100 is normal. When the drift rate 1306 under a certain condition is greater than 0.005%, the drift variation between the air inlet and the air outlet of the cooling tower 100 is abnormal.

[0128] refer to Fig.56D , an example chart 1320 is provided, which shows an evaluation of the change in the spray flow rate of the liquid distribution system 106. When changing from the baseline condition 1322 to the new condition 1324 and the new condition 1326, the spray flow rates 1328, 1330 of water increase. However, under the new condition 1326, the amount of PM2.5 and PM10 particulate matter 1332 at the outlet 130 of the cooling tower 100 is greater than the amount of particulate matter 1334 under the new condition 1324. Under the new condition 1324, the increase in PM2.5 and PM10 particulate matter 1334 at the outlet 130 can be attributed to the increase in the spray flow rate 1328 of the liquid distribution system 106, so the drift rate 1336 does not increase significantly. Under the new condition 1326, the amount of particulate matter 1332 at the air outlet 130 increases significantly and / or disproportionately relative to the increase in the spray flow rate 1330 of the liquid distribution system 106 (e.g., compared to the change to the new condition 1326). The controller 162 determines that the increase in particulate matter 1332 at the air outlet 130 is due to an abnormal increase in the drift rate of the cooling tower 100 that exceeds an acceptable or expected drift rate under these conditions because the increase in particulate matter 1332 is not entirely attributable to an increase in the spray flow rate 1330 or any other monitored variable. Alternatively or additionally, the controller 162 can calculate the drift rate 1336 for each condition and determine whether the drift rate is abnormal or normal based on a comparison with a drift rate threshold.

[0129] refer to Fig.56E, an example chart 1350 is provided, which shows an evaluation of the change in speed of the fan assembly 102 and the change in the spray flow rate of the liquid distribution system 106. When changing from the baseline condition 1352 to the new condition 1354 or the new condition 1355, the speed 1356, 1358 of the fan assembly 102 increases by 25%, and the spray flow rate 1360, 1362 of the water increases. However, under the new condition 1355, the amount of PM2.5 and PM10 particulate matter 1364 at the air outlet 130 of the cooling tower 100 is significantly greater (e.g., almost three times) than the amount of particulate matter 1366 under the new condition 1354. Under the new condition 1354, the increase in PM2.5 and PM10 particulate matter 1366 at the air outlet 130 can be attributed to the increase in the spray flow rate 1360 of the liquid distribution system 106 and the speed of the fan assembly 102, so that the drift rate 1368 increases by a normal amount. Under the new conditions 1355, the amount of particulate matter 1364 at the air outlet 130 increases significantly and / or disproportionately relative to the increase in the spray flow rate 1362 of the liquid distribution system 106 and the increase in the speed 1358 of the fan assembly 102 (e.g., compared to the change to the new conditions 1354). The controller 162 determines that the increase in particulate matter 1364 at the air outlet 130 is due to an abnormal increase in the drift rate of the cooling tower 100 that exceeds an acceptable or expected drift rate under these conditions because the increase in particulate matter 1364 is not entirely attributable to an increase in the spray flow rate 1362, the fan speed 1358, or any other monitored variable.

[0130] Unless otherwise indicated herein or clearly contradicted by context, the use of singular terms such as "a", "an" is intended to cover both the singular and the plural. The terms "comprising", "having", "including", and "containing" are to be construed as open-ended terms. The phrase "at least one" as used herein is intended to be interpreted in a disjunctive sense. For example, the phrase "at least one of A and B" is intended to cover A, B, or both A and B.

[0131] Although specific embodiments of the present invention have been illustrated and described, it will be appreciated that many variations and modifications will occur to those skilled in the art, and the present invention is intended to cover all those variations and modifications that fall within the scope of the appended claims. For example, it will be appreciated that the present disclosure may be applied to other processes for spraying water or other liquids, such as manufacturing processes.

Claims

1. An air contactor, comprising: An airflow generator for generating an airflow; a liquid distribution system operable to distribute liquid contacted by the gas stream; a sensor configured to detect an air variable of the airflow; a controller operably connected to the liquid dispensing system and the sensor, the controller being configured to: determining an operating variable of at least one of the air flow generator and the liquid distribution system; and A drift condition of the air contactor is determined based at least in part on an air variable of the air flow and an operational variable of at least one of the air flow generator and a liquid distribution system.

2. The air contactor according to claim 1, wherein: The drift condition includes an abnormal drift condition of the air contactor; and The controller is configured to determine the abnormal drift condition in response to: the air variable differs sufficiently from the expected air variable; and / or The operating variable differs sufficiently from the expected operating variable.

3. The air contactor according to claim 1, wherein: The drift condition includes a drift rate of the air contactor.

4. The air contactor according to claim 1, wherein: The drift condition includes an abnormal drift condition of the air contactor; wherein the controller is configured to determine a drift rate of the air contactor; and The controller is configured to determine the abnormal drift condition in response to a drift rate of the air contactor being an abnormal drift rate.

5. The air contactor according to claim 1, wherein: The drift condition includes an abnormal change in the drift of the air contactor.

6. The air contactor according to claim 1, wherein: The air variables include upstream air variables and downstream air variables; The sensor comprises: an upstream sensor configured to detect an upstream air variable of the airflow upstream of the airflow contacting the liquid; and A downstream sensor is configured to detect a downstream air variable of the airflow downstream of the airflow contacting the liquid.

7. The air contactor according to claim 6, wherein: The drift condition includes an abnormal drift condition; and Wherein the controller is configured to determine the drift condition based at least in part on the downstream air variable being abnormal relative to the upstream air variable.

8. The air contactor according to claim 1, wherein: The air variables include a first air variable associated with a first operating condition of the air contactor and a second air variable associated with a second operating condition of the air contactor; wherein the operating variables include a first operating variable associated with the first operating condition and a second operating variable associated with the second operating condition; wherein the drift condition includes an abnormal drift condition; and The controller is configured to determine an abnormal drift condition of the air contactor in response to: The second air variable changes abnormally relative to the first air variable; and / or The second manipulated variable changes abnormally relative to the first manipulated variable.

9. The air contactor according to claim 8, wherein: The airflow generator includes a fan assembly; wherein the first operating condition includes the controller being configured to operate the fan assembly at a first speed and control the liquid dispensing system to dispense liquid; and The second operating condition includes the controller being configured to operate the fan assembly at a second, different speed and control the liquid dispensing system to dispense liquid.

10. The air contactor according to claim 1, wherein: The drift condition is an abnormal drift condition; and Wherein the controller is configured to determine the abnormal drift condition based at least in part on a comparison of the air variables and the operational variables to a variable data set corresponding to a normal drift condition.

11. The air contactor according to claim 1, wherein: The operating variables include variables of the liquid; and Wherein the controller is configured to determine the drift condition based at least in part on the variable of the air and the variable of the liquid.

12. The air contactor according to claim 1, wherein: The controller is configured to process the air variables and the operating variables using a machine learning algorithm to determine the drift condition.

13. The air contactor according to claim 1, wherein: The operating variable of at least one of the airflow generator and the liquid dispensing system includes a first variable of the airflow generator and a second variable of the liquid dispensing system.

14. The air contactor according to claim 1, wherein: The airflow generator includes a fan assembly operable to generate the airflow; and The operating variables include fan assembly operating variables.

15. The air contactor according to claim 1, wherein: The air sensor comprises a particulate matter sensor; and The air variables include particle variables indicative of particulate matter in the air flow.

16. The air contactor according to claim 15, wherein: The particle sensor comprises: a first particulate matter sensor configured to detect particles of a first size; and a second particulate matter sensor configured to detect particles of a second, smaller size; and The granular variables include: a first particle variable indicative of particles of the first size in the airflow; and A second particle variable is indicative of particles of the second size in the airflow.

17. The air contactor according to claim 1, wherein: The sensors include a particle sensor, a relative humidity sensor, and a temperature sensor; and The air variables include particulate matter variables, relative humidity variables and air temperature variables.

18. The air contactor according to claim 1, wherein: The airflow generator includes a fan assembly; The operating variables of at least one of the airflow generator and the liquid distribution system include: a fan speed of the fan assembly; and The operating conditions of the liquid dispensing system.

19. The air contactor according to claim 1, wherein: The operating variables of at least one of the air flow generator and the liquid distribution system include: Operating conditions of the liquid dispensing system; and Variable of the liquid.

20. The air contactor according to claim 1, wherein: The sensor comprises: a channel for receiving a portion of the airflow; and A particle sensor is used to detect a particle variable of the portion of the airflow.

21. The air contactor according to claim 1, wherein: The sensor comprises: a channel for receiving a portion of the air flow; an air flow sensor for detecting an air variable of the portion of the air flow in the passage; and A heater, cooler, or both, is located in the passage upstream of the airflow sensor.

22. The air contactor according to claim 1, wherein: The controller is configured to adjust operation of at least one of the airflow generator and a liquid dispensing system in response to the determination of the drift condition.

23. The air contactor of claim 1, further comprising a pad, a filler, and / or an indirect heat exchanger; and Wherein the liquid distribution system is operable to distribute the liquid onto the pad, filler and / or indirect heat exchanger.

24. The air contactor according to claim 1, wherein: The liquid is an air pollutant capture solution.

25. The air contactor according to claim 1, wherein: The air contactor is a hyperbolic cooling tower; wherein the airflow generator is the shell of the hyperbolic cooling tower; and The operating variable is an operating variable of the liquid distribution system.

26. The air contactor according to claim 1, wherein: The operating variable of at least one of the air flow generator and the liquid dispensing system comprises a plurality of variables of the liquid dispensing system, the plurality of variables comprising: a first variable indicating whether a pump of the liquid dispensing system is operating; and A second variable is indicative of the electrical conductivity of the liquid.

27. A method of operating an air contactor having an air flow generator for generating an air flow, the method comprising: operating a liquid distribution system of the air contactor to distribute liquid, the air stream contacting the liquid; Detecting an air variable of the air flow through a sensor of the air contactor; determining an operating variable of at least one of the air flow generator and the liquid distribution system; and A drift condition of the air contactor is determined based at least in part on an air variable of the air flow and an operational variable of at least one of the air flow generator and a liquid distribution system.

28. The method according to claim 27, wherein: The airflow generator includes a fan assembly, and the method further includes: The fan assembly is operated to generate air flow from an air inlet to an air outlet of the air contactor.

29. The method according to claim 27, wherein: The drift condition of the air contactor is an abnormal drift condition, a drift rate of the air contactor, or an abnormal change in the drift of the air contactor.

30. The method of claim 27, wherein: The air variables include upstream air variables and downstream air variables; The sensor of the air contactor includes an upstream sensor and a downstream sensor; and The air variables for detecting the air flow include: detecting, by the upstream sensor, an upstream air variable of the airflow upstream of the airflow in contact with the liquid; and A downstream air variable of the air flow downstream of the air flow in contact with the liquid is detected by the downstream sensor.

31. The method according to claim 30, wherein: The drift condition is an abnormal drift condition; and Wherein determining the abnormal drift condition includes determining the drift condition based at least in part on the downstream air variable being abnormal relative to the upstream air variable.

32. The method of claim 27, wherein: The air variables include a first air variable associated with a first operating condition of the air contactor and a second air variable associated with a second operating condition of the air contactor; wherein the operating variables include a first operating variable associated with the first operating condition and a second operating variable associated with the second operating condition; wherein the drift condition includes an abnormal drift condition; and Wherein determining the abnormal drift condition of the air contactor is based at least in part on: an abnormal change from the first air variable to the second air variable; and / or An abnormal change from the first manipulated variable to the second manipulated variable.

33. The method of claim 27, wherein: The drift condition includes an abnormal drift condition; and Wherein determining the abnormal drift condition includes comparing the air variables and the operating variables to a variable data set corresponding to a normal drift condition.

34. The method of claim 27, wherein: Determining the drift condition includes processing the air variables and operating variables using a machine learning algorithm.

35. The method of claim 27, wherein: The operating variable of at least one of the airflow generator and the liquid dispensing system includes a first variable of the airflow generator and a second variable of the liquid dispensing system.

36. The method of claim 27, wherein: The air variables include a particle variable indicative of particulate matter in the airflow.

37. The method of claim 36, wherein: The air variables also include relative humidity variables and air temperature variables.

38. The method of claim 27, wherein: Air variables for detecting the air flow include: operating a fan of the sensor to direct a portion of the airflow through a passage of the sensor; heating at least a portion of the gas stream, cooling at least a portion of the gas stream, or both heating and cooling at least a portion of the gas stream; and An airflow variable of the portion of the airflow is detected.

39. The method of claim 27, wherein: Operating the liquid distribution system of the air contactor includes distributing the liquid onto at least one of: Liquid absorbent materials; Filling; and Indirect heat exchanger.

40. An apparatus for sensing drift in an air flow of an air contactor, the air flow having a first velocity in the air contactor, the apparatus comprising: an inlet for receiving a portion of the air flow; exit; an airflow generator configured to cause the portion of the airflow to have a second velocity corresponding to the first velocity of the airflow of the air contactor as the portion of the airflow travels between the inlet and the outlet; and A sensor is operable to detect an air variable of the portion of the airflow when the portion of the airflow travels at the second speed.

41. The device according to claim 40, wherein The airflow generator includes a fan assembly operable to cause the portion of the airflow to have the second velocity.

42. The device according to claim 40, wherein: The airflow generator includes an auxiliary fan assembly, the apparatus further comprising a controller operably coupled to the auxiliary fan assembly; wherein the controller is configured to receive an operating variable of a main fan assembly of the air contactor; and Wherein the controller is configured to control the auxiliary fan assembly based at least in part on an operating variable of a main fan assembly of the air contactor.

43. The device according to claim 42, wherein: The operating variable includes a fan speed of a main fan assembly of the air contactor.

44. The apparatus of claim 40, wherein: The airflow generator includes a channel including the inlet and the outlet, the channel being configured to cause the portion of the airflow to have the second velocity in response to the inlet receiving the portion of the airflow at the first velocity.

45. The apparatus of claim 40, wherein: The airflow generator includes a louver operable to cause the portion of the airflow to have the second velocity when traveling between the inlet and the outlet.

46. ​​The apparatus of claim 40, wherein: The sensor includes a particulate matter sensor.

47. The apparatus of claim 40, wherein: The air flow generator is configured to make the partial air flow have the second velocity, which is the same as the first velocity of the air flow in the air contactor.

48. The apparatus of claim 40, wherein: The airflow generator includes a channel and further includes a heater, a cooler, or both in the channel upstream of the sensor.

49. The device according to claim 40, wherein The air flow generator includes a channel having a straight pipe portion and an elbow portion.

50. The apparatus of claim 40, further comprising a dehumidifier operable to dehumidify the portion of the air flow traveling from the air inlet to the air outlet upstream of the sensor.

51. The apparatus of claim 40, wherein: The sensor comprises: a first particulate matter sensor configured to detect particles of a first size; and a second particulate matter sensor configured to detect particles of a second, smaller size; and The air variables include: a first particle variable indicative of particles of the first size in the airflow; and A second particle variable is indicative of particles of the second size in the airflow.

52. The apparatus of claim 40, wherein: The sensor comprises: Particle sensor; Relative humidity sensor; Temperature sensor; Bacteria sensors; Carbon monoxide sensor; Carbon dioxide sensor; Volatile organic compound sensors; or Its combination.

53. The apparatus of claim 40, wherein: The air flow generator includes a channel having a collecting portion configured to collect liquid separated from the portion of the air flow.

54. The apparatus of claim 53, wherein: The sensor comprises a sensor for detecting a variable of the liquid.

55. The apparatus of claim 40, wherein: The air inlet includes a filter.

56. A method of sensing drift in an air flow of an air contactor, the method comprising: determining a variable representative of a first velocity of airflow in the air contactor; controlling the drift sensing device so that the portion of the airflow entering the drift sensing device at the first speed travels in the channel of the drift sensing device at a second speed corresponding to the first speed; and When the partial airflow travels in the passage at the second speed, an air variable of the partial airflow is detected by a sensor.

57. The method of claim 56, wherein: Determining a variable representative of a first speed of the airflow includes determining a speed of a fan assembly of the air contactor.

58. The method of claim 56, wherein: Determining a variable representative of a first speed of the airflow includes detecting the first speed of the airflow using an air speed sensor.

59. The method of claim 56, wherein: Controlling the drift sensing device includes operating a fan of the drift sensing device to cause the airflow to travel in the passage at the second speed.

60. The method of claim 56, wherein: Controlling the drift sensing device includes selectively opening at least one of an inlet and an outlet of the passage to cause the portion of the airflow to travel in the passage at the second speed.

61. The method of claim 56, wherein: Detecting an air variable of the portion of the airflow includes detecting particulate matter of the airflow.

62. The method of claim 56, further comprising dehumidifying the portion of the airflow upstream of the sensor.

63. The method of claim 56, further comprising separating a liquid from the portion of the gas stream; and The detecting of the air variable comprises detecting a variable of a liquid separated from the partial airflow.

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