Heat removal device, plume reduction system, and method

Abstract

In one aspect, a heat removal device is provided that includes an evaporative heat exchanger and a primary fan operable to direct first ambient air to an air inlet, cause the first ambient air to interact with the evaporative heat exchanger to generate heated air, and exhaust the heated air through an air outlet. The heat removal device also includes a plume abatement fan operable to direct second ambient air into contact with the heated air downstream of the evaporative heat exchanger, and a controller operably coupled to the primary fan and the plume abatement fan. The controller has a plume abatement mode, and during the plume abatement mode, the controller operates the plume abatement fan to cause the plume abatement fan to direct the second ambient air into contact with the heated air to cool the heated air and abatement the plume.

Description

Technical Field

[0001] Cross - reference to Related Applications

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 117,244, filed on November 23, 2020, which is hereby incorporated by reference in its entirety.

[0002] Field

[0002] The present disclosure relates to plume reduction systems, and more particularly, to plume reduction systems for heat removal devices having an evaporative heat exchanger.

Background Art

[0003] Background

[0003] Heat removal devices such as cooling towers may utilize one or more evaporative heat exchangers to cool a process fluid. As used herein, the term evaporative heat exchanger refers to a heat exchanger that utilizes evaporative cooling to cool a process fluid. Evaporative heat exchangers utilized in cooling towers may include direct evaporative heat exchangers, such as fill sheets, where the process fluid is directly cooled by an air stream. Alternatively, evaporative heat exchangers utilized in cooling towers may include indirect evaporative heat exchangers where the process fluid is separated from the cooling air stream by an intervening structure. For example, an indirect evaporative heat exchanger may include one or more serpentine circuit tubes or plate cassettes having an interior through which the process fluid passes, and an evaporative liquid distribution assembly that distributes an evaporative liquid over the outer surface of the serpentine circuit tubes.

[0004]

[0004] Evaporative heat exchangers often utilize water as the process fluid. Under certain atmospheric conditions, particularly in low-temperature environments, the evaporative heat exchange process can result in a plume of evaporated water vapor rising from the cooling tower. Under certain atmospheric conditions, if the evaporated water vapor or moisture is too concentrated to be readily absorbed by the surrounding air, a plume of water vapor becomes visible. If there is little wind above the cooling tower, the plume can rise mostly vertically. In the case of light to strong winds, the plume can follow the wind path. Depending on the surrounding conditions and the size of the cooling tower, the plume can extend from a few feet to several thousand feet above the cooling tower. As the concentrated moisture in the cooling tower exhaust mixes with the surrounding air, it is eventually absorbed and dissipates until the plume is no longer visible.

[0005]

[0005] Large plumes can be undesirable, especially near airports and in urban areas, because they can cause fog. Furthermore, plumes can obstruct or impede visibility and may appear to observers as smoke carrying pollutants. [Brief explanation of the drawing]

[0006] Brief explanation of the drawing [Figure 1]

[0001] This is a schematic diagram of a first cooling tower including a direct evaporative heat exchanger and a visible plume rising from the cooling tower. [Figure 2]

[0002] This is a cyclometric chart showing the supersaturation region in which a plume can be formed by the evaporative heat exchanger of the cooling tower. [Figure 3]

[0003] This is a schematic diagram of a second cooling tower having a plume reduction system. [Figure 4]

[0004] This is a schematic diagram of a third cooling tower having a plume reduction system. [Figure 5]

[0005] Control logic that may be used with the second and third cooling towers is shown. [Figure 6]

[0006] This is a schematic diagram of a fourth cooling tower having a plume reduction system. [Figure 7A]

[0007] This is a schematic diagram of a fifth cooling tower having an external plume reduction chamber. [Figure 7B]

[0008] This is a cross-sectional view of the lower part of the cooling tower in Figure 7A, taken across the line 7B-7B in Figure 7A. [Figure 8]

[0009] The control logic that can be used with the fourth and fifth cooling towers is shown. [Figure 9A]

[0010] This is a schematic diagram of a first vapor stack with a plume reduction system. [Figure 9B]

[0011] This is a schematic diagram of a second vapor stack with a plume reduction system. [Figure 10]

[0012] The control logic that can be used with the first and second steam stacks is shown. [Figure 11]

[0013] This is a schematic diagram of the sixth cooling tower equipped with a plume reduction system. [Figure 12]

[0014] This is a schematic diagram of the seventh cooling tower equipped with a plume reduction system. [Modes for carrying out the invention]

[0007] Detailed description

[0015] In one aspect of the present disclosure, a heat removal system is provided which includes an evaporative heat exchanger configured to cool a process fluid. The evaporative heat exchanger may include a direct heat exchanger and / or an indirect heat exchanger. The heat removal system includes at least one main fan operable to direct first ambient air into the air inlet of the heat removal system, causing the first ambient air to interact with the evaporative heat exchanger to produce heated air with increased moisture content, and to discharge the heated air from the air outlet of the heat removal system. The heat removal system further includes at least one plume mitigation fan operable to direct ambient air around the evaporative heat exchanger to come into contact with and mix with the heated air. Adding cooler ambient air from at least one plume mitigation fan to the heated air leaving the evaporative heat exchanger can reduce the temperature difference between the heated air leaving the evaporative heat exchanger and the ambient air, thereby reducing the risk of plume formation as the mixed airflow leaves the cooling tower. The heat removal system includes a controller operablely coupled to at least one main fan and at least one plume mitigation fan. The controller is configured to receive data from one or more sensors and / or from a remote computer. Based on the data, when the controller is in plume mitigation mode, the controller determines whether to activate at least one plume mitigation fan to direct ambient air into the cooling tower to come into contact with and mix with the heated air leaving the evaporative heat exchanger.

[0008]

[0006] In one embodiment, at least one plume reduction fan is operable to direct ambient air to come into contact with and mix with heated air inside a heat removal device, such as within the plenum of a heat removal device downstream of an evaporative heat exchanger. Alternatively or additionally, at least one plume reduction fan is operable to direct ambient air to come into contact with and mix with heated air outside the heat removal device. For example, at least one plume reduction fan may be mounted adjacent to the outlet of the heat removal device and configured to direct ambient air to come into contact with and mix with heated cooling tower exhaust as the heated air exits the outlet of the heat removal device.

[0009]

[0007] In one embodiment, at least one main fan includes multiple fans, and the plume reduction fan includes multiple fans. The controller has a cooling mode in which the controller rotates the main fan and the plume reduction fan in a first direction, so that the main fan and the plume reduction fan work together to direct a first ambient air to the air inlet, causing the first ambient air to interact with the evaporative heat exchanger to produce heated air, which is then discharged from the air outlet. When the controller decides to operate in plume reduction mode, the controller rotates the main fan in the first direction while rotating the plume reduction fan in the opposite, second direction. The rotation of the plume reduction fan in the second direction causes the plume reduction fan to direct ambient air to come into contact with and mix with the heated air in order to cool the heated air and reduce its moisture content before it leaves the cooling tower.

[0010]

[0008] In one aspect of the present disclosure, a method is provided for reducing plume in a heat removal device. The method includes drawing a first flow of ambient air into the heat removal device and directing the first flow of ambient air to flow toward an evaporative heat exchanger such that the first flow of ambient air absorbs heat from the evaporative heat exchanger to form a heated air mixture within the heat removal structure. The method further includes drawing a second flow of ambient air into the heat removal structure such that the second flow of ambient air bypasses the evaporative heat exchanger and mixes with the heated air discharged from the evaporative heat exchanger within the heat removal structure to form a cooled air mixture before it leaves the cooling tower. The second flow of ambient air is drawn into the heat removal structure (e.g., via a fan) without passing through the evaporative heat exchanger. The second flow of ambient air may have a temperature lower than the temperature of the heated evaporative heat exchanger exhaust within the heat removal structure. The method further includes discharging the cooled air mixture from the heat removal structure.

[0011]

[0009] The method may include rotating a first fan in a first direction to draw a first flow of ambient air into an evaporative heat exchanger, and rotating a second fan in a second direction opposite to the first direction to draw a second flow of ambient air into a heat removal structure. After discharging the cooled air mixture from the heat removal structure, the method may include directing a third flow of ambient air into the cooled air mixture to further cool and reduce the water content of the discharged cooled air mixture, thereby reducing the plume.

[0012]

[0010] In another aspect of the present disclosure, a plume reduction system is provided for a heat removal structure. The plume reduction system may be an evaporative heat exchanger aftercooler. The system includes a first fan for drawing a first flow of ambient air through the evaporative heat exchanger into the heat removal structure so that the first flow of ambient air absorbs heat from the evaporative heat exchanger to form a heated air mixture within the heat removal structure. The system further includes a second fan for drawing a second flow of ambient air around the evaporative heat exchanger into the heat removal structure so that the second flow of ambient air mixes with the heated air exiting the evaporative heat exchanger within the heat removal structure to form a cooled air mixture before exiting the heat removal structure. The second flow is drawn into the heat removal structure without passing through the evaporative heat exchanger.

[0013]

[0011] In one approach, the plume mitigation determination method may be carried out by a controller of the heat removal structure. For example, before implementing a plume mitigation measure, the method may include determining, via the controller's control logic, whether or not a plume is expected to form from the cooling tower, taking into account current and / or expected atmospheric conditions. If a plume is not expected to form, the method may continue to monitor for potential plume formation. If a plume is expected to form, the method may proceed to determine whether plume mitigation can be carried out while still meeting the cooling demand. If the cooling demand would not be met by implementing the plume mitigation measure, the method may continue to monitor changes in the cooling demand and continue to monitor atmospheric conditions for potential plume formation. If the cooling demand would be met by implementing the plume mitigation measure, the routine may proceed to implement the plume mitigation measure.

[0014]

[0012] Referring here to Figure 1, an evaporation system 10 for a heat removal device such as a cooling tower 12 is shown without a plume reduction function. The evaporation system 10 includes a hot water tank 20 and an evaporative heat exchanger, which may be in the form of a direct-to-intermediate packing 22. Alternatively, the evaporative heat exchanger may be an evaporative indirect heat exchanger coil containing the process fluid. During the cooling process, a heated process fluid, such as water, is pumped into the hot water tank 20. From the hot water tank 20, the heated water is distributed across the packing 22 (e.g., through holes or nozzles 24). The water then flows down along the packing 22 by gravity and is drawn in through an air outlet 31 by one or more main fans, such as a fan 30, and cooled by ambient air shown in 32 interacting with the packing 22. The cooled water is then collected in a chilled water tank 34, from which the cooled water is returned to the system process flow.

[0015]

[0013] During the cooling process, a portion of the water moving along the packing 22 evaporates to form water vapor. The water vapor is drawn by the fan 30 into the exhaust plenum 40 of the cooling tower 12, which can be intermediate the packing 22 and the air outlet 31. Thereafter, the water vapor is discharged from the cooling tower 12 at the air outlet 41 by the fan 30. Under certain atmospheric conditions, the discharged exhaust 42 forms one or more plumes 44 outside the cooling tower 12.

[0016]

[0014] More specifically, referring next to FIG. 2, a psychrometric chart 50 having a plume zone 52 above the saturation curve 72 is shown. The plume zone 52 indicates the atmospheric conditions under which a plume may occur when the discharged exhaust 42 contacts the ambient air. Air having a state that enters the plume zone 52 is supersaturated air, i.e., the relative humidity of the air is higher than 100%. Excess moisture in the supersaturated air condenses into droplets, and the suspension of the droplets in the air results in a plume.

[0017]

[0015] Line 54 illustrates the air conditions during the air cycle of an exemplary cooling tower. As considered, one or more fans 30 draw ambient air into the cooling tower 12. Before entering the cooling tower 12, the ambient air is at 21°F dry bulb and 17°F wet bulb, as shown in state 60. As the air passes through the evaporative heat exchanger (e.g., packing 22 in Figure 1), the air extracts heat and moisture from the heated water passing through the evaporative heat exchanger. As this heated air is discharged from the cooling tower 12, the discharged exhaust air 42 in Figure 1 is at 65°F dry bulb and 65°F wet bulb, as shown in state 62. As the heated exhaust air 42 mixes with the cooler ambient air, the state of the exhaust air 42 progresses along line 54 from state 62 (65°F dry bulb) to state 64 (56°F dry bulb), state 66 (46°F dry bulb), state 68 (38°F dry bulb), state 70 (30°F dry bulb), and finally reaches ambient air state 60 (21°F dry bulb). In this example, when the exhaust air 42 is between state 62 and state 70 on line 54, the air is above the saturation curve 72, as shown, for example, by 66'. This air is supersaturated, and the excess water vapor will be seen as a plume. When the exhaust air 42 of plume 44 is completely mixed with the ambient air at state 60, the saturation of the air falls below the saturation curve 72, and the plume 44 completely dissipates. However, this may not occur until the plume reaches a distance of several to several thousand feet from the cooling tower.

[0018]

[0016] To reduce or eliminate the plume, plume reduction measures can be implemented to forcefully mix the ambient air with the exhausted air 42 within and / or immediately after the exhaust from the cooling tower. Such measures can include adjusting the operation of one or more fans 30 in FIG. 1 (e.g., adjusting the rotational direction of the fan blades), tilting the axis of rotation of one or more fans 30 to improve mixing within the exhaust plenum 40, and / or providing additional components as will be described in more detail hereinafter. The plume reduction measures contemplated herein can reduce the temperature and / or water content of the exhaust air discharged from the cooling tower such that the exhaust air discharged from the cooling tower exits at an atmospheric condition corresponding to a condition between state 62 and state 60 on line 54.

[0019]

[0017] Referring to Figure 3, a cooling tower 102 is provided which includes a plume reduction system 100 and includes components similar to those of the cooling tower 12 shown in Figure 1 (similar reference numerals refer to similar components). The cooling tower 12 has an evaporative heat exchanger, such as packing 22, which may be located in the outer structure of the cooling tower 102. The cooling tower 102 also has fans 130, including a main fan such as fan 130A, and plume reduction fans 130B, 130C. The plume reduction system 100 may include a controller 110 for controlling various components of the cooling tower 102 (e.g., fans, airflow control valves, etc.) to cool the process fluid and reduce the plume. As will be described in more detail later, when the controller 110 is operating in cooling mode, the plume reduction fan 130B may rotate in cooperation with the fan 130A to direct air into the air inlet 131 of the cooling tower 102, through the packing 22, into the internal plenum 40, and out through the air outlet 133 of the cooling tower 102. When the controller 110 is operating in plume reduction mode, the plume reduction fan 130B rotates in the opposite, second direction to direct ambient air 132 into the plenum 40 to mix with the heated air mixture 144 downstream from the packing 22 and upstream from the air outlet 133. The ambient air 132 mixes with the heated air mixture 144 in the plenum 40, cooling the heated air mixture 144 before it is discharged from the air outlet 133 to reduce its moisture content and reduce or eliminate plume formation.

[0020]

[0018] The controller 110 may include a memory 112, a processor 114, and a communication circuit 116. The memory 112 is configured to store information such as plume reduction commands, a predetermined set temperature or set temperature range, and a deadband temperature value (described in more detail later). The processor 114 is configured to execute commands stored in the memory 120, such as causing one or more fans to start, stop, increase speed, decrease speed, reverse direction, etc., and / or modulate one or more airflow control valves to a partially or fully open or closed position. The communication circuit 116 is configured to transmit and / or receive wired and / or wireless communications. For example, the communication circuit 116 may be configured to communicate directly or indirectly with a control station to receive commands or transmit system information.

[0021]

[0019] In the shown approach, fans 130A and 130B are provided above and across the exhaust plenum 40 of the cooling tower 102. Fans 130A and 130B may include a motor and fan blades driven by the motor. The blades of fans 130A and 130B may generally rotate in a common plane or be tilted as considered with respect to Figure 4. Fans 130A and 130B may be direct-drive fans, and the speeds of fans 130A and 130B may be independently controlled and varied so that the temperature of the process fluid discharged from the cooling tower 102 is cooled to a set temperature. For example, when the cooling demand increases, the fan speed may be increased to cause a higher airflow rate across the packing 22, thereby increasing the cooling rate in the packing 22. When the cooling demand decreases, the fan speed may be decreased, thereby decreasing the airflow velocity across the packing 22.

[0022]

[0020] One or more of the fans 130A, 130B are configured to rotate in a first direction (for example, to direct ambient air 32 through the packing 22 and exhaust air from the exhaust plenum 40), and further configured to rotate in a second opposite direction (for example, to direct ambient air 132 into the exhaust plenum 40). Fans rotating in the first direction tend to remove air from the exhaust plenum 40 and reduce the pressure in the exhaust plenum 40, while fans rotating in the second direction tend to direct air into the exhaust plenum 40, bypassing the evaporative heat exchanger 22, and increasing the pressure in the exhaust plenum 40. In one example, if ambient conditions are such that no plume forms, as determined by the controller 110, the fans 130A, 130B may be operated to direct ambient air 32 through the packing 22 to the exhaust plenum 40 and to flow air in the same direction to discharge it from the exhaust plenum 40 as exhaust air 142. When fans 130A and 130B are rotating in the same direction to expel exhaust air from the exhaust plenum 40, they may be controlled to operate at the same speed or at different speeds.

[0023]

[0021] If ambient conditions determine, either by the control logic of the controller 110 of the cooling tower 102 or by the input from the plume detector 146, that the high-temperature exhaust air 142 will cause a plume and that the cooling requirements of the cooling tower 102 are met with the plume mitigation measures activated, one or more fans 130A, 130B may be operated to rotate in opposite directions. For example, fan 130A, sometimes called the main fan, can be operated in a first direction as an "updraft" fan, drawing in ambient air 32 through the packing 22 and driving the exhaust air 142 out of the exhaust plenum 40, while fan 130B, sometimes called the plume mitigation or auxiliary fan, is operated in the opposite second direction as a "downdraft" fan, pushing ambient air 132 from the top of the cooling tower 12 into the exhaust plenum 40 without directing it through the packing 22. Fan 130B can operate as an updraft fan in a first direction when plume reduction is not needed or unavailable, and can be switched to operate as a downdraft fan in a second direction in plume reduction mode.

[0024]

[0022] The ambient air 132 pushed into the cooling tower 12 by fan 130B may have a lower temperature and moisture content than the heated air mixture 144 drawn into the exhaust plenum 40 via the packing 22 by fan 130A. The ambient air 132 pushed into the exhaust plenum 40 by fan 130B is mixed with the heated air mixture 144 in the exhaust plenum 40 before the resulting lower temperature and moisture content exhaust air 142 is expelled from the cooling tower 12 by fan 130A. In this way, the exhaust air 142 expelled from the exhaust plenum 40 by fan 130A is already cooled by the ambient air 142 directed into the exhaust plenum 40 by fan 130B. By cooling the air in the exhaust plenum 40, the exhaust air 142 can leave the cooling tower 102 with characteristics along line 54 (see Figure 2), i.e., below the 100% relative humidity line 72, thereby reducing or eliminating plume. For example, pre-cooled exhaust air exits the cooling tower 102 at points 64, 66, 68, or 70, rather than at point 62. If the pre-cooled exhaust air exits the cooling tower 102 between points 70 and 62, a plume may be observable, but to a lesser degree than if the exhaust air were at point 62. At point 70, the moisture content of the exhaust air 142 matches the maximum moisture content of the ambient air. The exhaust air 142 is not supersaturated and therefore does not produce a plume.

[0025]

[0023] The control logic of the controller 110 can continuously determine how many fans 130A, 130B are needed to meet the cooling tower load and how many fans are available to reduce the plume. The controller 110 can independently control fan parameters (e.g., direction and / or speed) to optimize plume reduction. For example, in an alternative approach, one or more fans 130B may be operated to draw in ambient air 32 through the packing 22 and expel exhaust air 142 from the exhaust plenum 40, while one or more fans 130A may be operated to push ambient air 132 into the exhaust plenum 40 from above the cooling tower 12.

[0026]

[0024] In one approach, the cooling tower 102 includes one or more auxiliary or external fans 130C for mixing exhaust air 142 from the exhaust plenum 40 with additional ambient air 152. Mixing the additional ambient air 152 with the exhaust air 142 reduces the temperature and moisture content of the exhaust air 142, thereby further reducing or eliminating plume formation above the cooling tower 102. The external fan 130C can be mounted adjacent to the air outlet 133. For example, the external fan 130C may be located outside the outer structure of the cooling tower 102 (e.g., on the top or upper surface). The external fan 130C may include one or more mounting mechanisms that allow the external fan 130C to move relative to the cooling tower 102. In this way, components below the external fan 130C (e.g., the hot water tank 20) ​​may be accessible (e.g., for maintenance). In one example, a hinge 154 is provided so that the external fan 130C can pivot relative to the cooling tower 102. In another example, the external fan 130C may be slidably mounted relative to the cooling tower (for example, along a rail). The external fan 130C, having an associated plume mitigation logic controller 110, may be added to an existing evaporative heat exchanger or cooling tower application as an "aftermarket" component for plume mitigation.

[0027]

[0025] The speed and direction of each individual fan 130A, 130B, and 130C can be controlled independently. In this way, the control logic of the controller 110 can determine the optimal use of fans 130A, 130B, and 130C to meet the load on the cooling tower while reducing the plume when desired.

[0028]

[0026] Referring to Figure 4, a cooling tower 202 is provided which includes a plume mitigation system 200, which includes components similar to those of the cooling tower 12 shown in Figure 1 (similar reference numerals refer to similar components). The plume mitigation system 200 may include a controller 210 having a memory 212, a processor 214, and a communication circuit 216, and a plume detector 146 which may be similar to that of Figure 3.

[0029]

[0027] When the plume reduction system 200 operates the cooling tower 202 in plume reduction mode, an auxiliary fan or plume reduction fan, such as fan 230B, may be operated in the opposite direction to the rotation of fan 230A, which may be called the main fan. In this embodiment, fan 230A draws in ambient air 32 through the air inlet 231 and passes it through the meandering coil 22' to expel exhaust air 242 out of the exhaust plenum 40 through the air outlet 233, while fan 230B pushes ambient air 232 into the exhaust plenum 40. The ambient air 232 pushed into the exhaust plenum 40 by fan 230B may have a lower temperature and moisture content than the heated air mixture 244 drawn into the exhaust plenum 40 through the packing 22 by fan 230B. The ambient air 232, pushed into the exhaust plenum 40 by fan 230B, cools down by mixing with the heated air mixture 244 in the exhaust plenum 40 downstream of the packing 22, reducing its water content. The resulting exhaust air 242 is then expelled from the cooling tower 12 by fan 230A (for example, upstream of the air outlet 233).

[0030]

[0028] In this approach, one or more of the fans 230A, 230B may have an axis of rotation that is tilted or offset with respect to the vertical, as indicated by angles 234A, 234B, respectively. The axis of rotation of fan 230A may be oblique with respect to the axis of rotation of fan 230B. In the exemplary approach shown, the fan of fan 230B may be tilted outward to facilitate the intake of ambient air 232 along a path away from the exhaust air 242, while fan 230A is tilted inward to direct the exhaust air 242 more vertically, away from the path of the ambient air 232. The optional tilt of the fan also helps to mix the ambient air 232 in the exhaust plenum 40 before it is exhausted by fan 230A.

[0031]

[0029] In one embodiment, one or more external fans (for example, the external fan 130C in Figure 3) may be provided to the plume reduction system 200 to provide further plume reduction.

[0032]

[0030] Referring to Figure 5, a method 201 for controlling a plume reduction system for a heat removal structure is shown. The plume reduction system may generally correspond to the plume reduction system 100 in Figure 3 or the plume reduction system 200 in Figure 4. The heat removal structure may be a cooling tower such as the cooling tower 102 in Figure 3 or the cooling tower 202 in Figure 4.

[0033]

[0031] Method 201 includes determining whether the cooling tower cooling mode is activated (203). As considered, when the cooling tower is operating in cooling mode, a heated evaporative fluid such as water is distributed along the evaporative heat exchanger packing 22, coils, and / or plates. One or more fans (e.g., fan 130A in Figure 3 or fan 230A in Figure 4) draw in ambient air 32 through the packing 22 and expel exhaust air 242 from the exhaust plenum 40.

[0034]

[0032] When the cooling tower is operating in cooling mode, method 201 includes determining, via the control logic of controllers 110, 210, whether the temperature of the heated evaporative fluid exceeds a threshold temperature or threshold temperature range (205). The temperature of the heated evaporative fluid may be measured before the heated evaporative fluid passes through the evaporative heat exchanger (e.g., packing 22). For example, the temperature may be measured in the hot water tank 20, or elsewhere upstream from the packing 22, or at the inlet or outlet of the process.

[0035]

[0033] The threshold temperature range may include a predetermined set temperature and a deadband temperature value. For example, the set temperature may be 85°F and the deadband temperature value may be 2°F such that the threshold temperature range is 83°F to 87°F.

[0036]

[0034] If the heated evaporative fluid exceeds the threshold temperature range (for example, the heated evaporative fluid is 90°F in the above example), the current operation of the cooling tower may be insufficient to meet the cooling demand. Therefore, method 201 may include determining whether an action to increase the cooling capacity is available. For example, method 201 includes determining whether one or more updraft fans are operating at maximum speed (207). If one or more updraft fans are not operating at maximum speed, method 201 includes increasing the speed of one or more updraft fans (209). Method 201 then returns to operation 203 and repeats if the temperature of the heated evaporative fluid is still above the threshold temperature range and all updraft fans are not operating at maximum speed.

[0037]

[0035] If the temperature of the heated evaporative fluid exceeds the threshold temperature range and all updraft fans are operating at maximum speed, the method includes adjusting one or more downdraft fans that are operating in plume-reducing downdraft mode by blowing ambient air into the exhaust plenum (211). For example, if the temperature of the heated evaporative fluid exceeds the threshold temperature range and some fans are operating in updraft mode while others are operating in plume-reducing downdraft mode, method 201 may include reducing the speed of the downdraft fans to reduce the amount of ambient air entering the plenum 40. If this is still not enough to maintain an appropriate temperature, method 201 includes changing the operation of the fans that were in plume-reducing downdraft mode to operate in updraft mode to provide more airflow directed through the packing 22. If the cooling tower is equipped with an auxiliary or external plume mitigation fan (e.g., 130C in Figure 3) positioned adjacent to the air outlet, and all fans inside the cooling tower are operating at maximum speed for updraft (i.e., none of the internal fans are used for plume mitigation), and the temperature is still above a setpoint, the speed of the auxiliary plume fan may be adjusted to mitigate the plume outside the cooling tower. In this case, method 201 proceeds to increase the speed of one or more external plume mitigation fans (215).

[0038]

[0036] In one embodiment, if the cooling tower includes one or more external fans, such as the external fan 130C in Figure 3, method 201 may include determining whether the cooling tower is operating in plume mitigation mode and whether a plume is detected or predicted (for example, as determined or notified by the controller 110 or 210) (213). If the cooling tower is operating in plume mitigation mode and a plume is detected or predicted, method 201 includes increasing the speed of one or more external fans (215).

[0039]

[0037] As discussed, method 201 includes adjusting the speed or direction of one or more downdraft fans that are blowing ambient air into the exhaust plenum (211). If the direction of the downdraft fans is reversed, method further includes determining whether all fans are operating as updraft fans (217). If all fans are operating as updraft fans, the fans may operate at the same speed (219), which may be the maximum speed for each fan as set in operation 209. With all fans operating at maximum speed as updraft fans, the cooling tower is operating in maximum cooling mode.

[0040]

[0038] Returning to operation 205, if the temperature of the heated evaporative fluid does not exceed the threshold temperature range, one or more plume reduction fans (e.g., fan 130B or 230B) may be operated in plume reduction mode. Thus, method 201 includes determining whether the temperature of the heated evaporative fluid is below the threshold temperature range (221). A working fluid temperature (e.g., 80°F) below the threshold temperature range (e.g., 83°F to 87°F) may indicate supercooling, and if such a determination is made, method 201 may include reducing the speed of one or more updraft fans (223).

[0041]

[0039] When the temperature of the heated evaporative fluid is neither above nor below the threshold temperature range (i.e., equal to the temperature in the threshold temperature range), the cooling operation of the cooling tower has achieved the desired evaporative fluid temperature. Method 201 may proceed to implement one or more plume mitigation measures when instructed and as needed.

[0042]

[0040] Thus, method 201 includes determining (225) whether the cooling tower is operating in plume reduction mode and whether a plume is detected or predicted (e.g., as determined or notified by controller 110 or 210). Determination 225 may include determining the plume state based at least in part on ambient air variables (e.g., dry bulb temperature). If the cooling tower is not operating in plume reduction mode and no plume is detected or predicted, method 201 returns to operation 203.

[0043]

[0041] If the cooling tower is operating in plume mitigation mode and a plume is detected or predicted, method 201 includes determining whether one or more updraft fans are operating at maximum speed (227). If one or more updraft fans are not operating at maximum speed, plume mitigation measures can be implemented without reducing the cooling efficiency of the updraft fans. Thus, method 201 may include increasing the fan speed of one or more downdraft fans to draw in additional ambient air into the exhaust plenum of the cooling tower (229). Furthermore, if the cooling tower includes one or more external fans, such as external fan 130C in Figure 3, method 201 may include increasing the speed of one or more external fans to further mitigate the plume (231).

[0044]

[0042] When all updraft fans are operating at maximum speed, the additional ambient air in the exhaust plenum may reduce the cooling efficiency of the updraft fans. Therefore, when all updraft fans are operating at maximum speed, the downdraft speed is kept constant, and method 201 may revert to operation 203. However, external fans may still reduce the plume when all updraft fans are operating at maximum speed without reducing the cooling efficiency of the updraft fans. Therefore, when the cooling tower includes one or more external fans, such as external fan 130C in Figure 3, method 201 may include increasing the speed of one or more external fans (231) to further reduce the plume.

[0045]

[0043] Referring to Figure 6, a cooling tower 302 is provided which includes a plume mitigation system 300, which includes components similar to those of the cooling tower 12 shown in Figure 1 (similar reference numerals refer to similar components). The plume mitigation system 300 may include a controller 310 having a memory 312, a processor 314, and a communication circuit 316, and a plume detector 346 which may be similar to that of Figure 3.

[0046]

[0044] The plume reduction system 300 may include a single fan 330A, sometimes called the main fan, which spreads out over the exhaust plenum 40. Fan 330A may be operated to draw in ambient air 32 through the air inlet 331 and the packing 22 and to expel exhaust air 342 from the exhaust plenum 40. In another approach, multiple fans (e.g., fan 30 in Figure 1) are provided to draw in ambient air 32 through the packing 22 and expel exhaust air 342 from the exhaust plenum 40. In yet another approach, one or more fans (e.g., fan 130A in Figure 3) are provided to draw in ambient air 32 through the packing 22 and expel exhaust air 342 from the exhaust plenum 40, while one or more fans (e.g., fan 130B in Figure 3) are provided to push ambient air 352 into the exhaust plenum 40. One or more fans may be angled, as described with respect to Figure 4.

[0047]

[0045] Similar to the cooling tower 102 in Figure 3, the cooling tower 302 in Figure 6 may include one or more auxiliary fans, such as an external fan 330B, for mixing the exhaust air 342 exiting the exhaust plenum 40 with additional ambient air 352. Mixing the additional ambient air 352 with the exhaust air 342 reduces the temperature and moisture content of the exhaust air 342, thereby reducing or eliminating plume formation above the cooling tower 302. The external fan 330B may be movably connected to the cooling tower 302 (e.g., via a hinge 354) to allow access to components of the cooling tower 302 (e.g., for maintenance).

[0048]

[0046] The cooling tower 302 may further include one or more airflow control valves 360 that can be adjusted to allow additional ambient air 362 outside the cooling tower 302 to be drawn into the exhaust plenum 40 by the fan 330A and mixed with the heated air in the exhaust plenum 40 downstream of the packing 22 and upstream of the air outlet 333. An airflow control valve motor 364 may be provided to adjust the position of the airflow control valve 360 ​​via an airflow control valve coupling 366 connected to the airflow control valve 360. The position of the airflow control valve 360 ​​(e.g., fully open, partially open, or fully closed) may be operated by the controller 310 of the cooling tower 302 to reduce plume. For example, when the cooling tower 302 is meeting the cooling demand and the fan 330A is operating at a fan speed of less than 100%, the airflow control valve motor 364 can open the airflow control valve 360 ​​to reduce plume.

[0049]

[0047] One or more auxiliary plume reduction fans 370 may be provided to add additional ambient air 362 to the exhaust plenum 40 when additional plume reduction is desired. The plume reduction fans 370 may be located on the external or internal side walls of the cooling tower 302 and may be positioned to rotate about a transverse axis, such as perpendicular to the rotation axis of the fan 330A. The plume reduction fans 370 may be positioned adjacent to the airflow control valve 360 ​​and below the fan 330A so that the plume reduction fans 370 draw the additional ambient air 362 into the exhaust plenum 40 via the airflow control valve 360 ​​before the fan 330A expels the mixture of heated ambient air 32 and additional ambient air 362 from the exhaust plenum 40. In plume reduction mode, the airflow control valve 360 ​​can be fully opened to reduce the plume and the plume reduction fans 370 can be turned on to add the additional ambient air 362 to the exhaust plenum 40. The speed of the plume reduction fan 370 may be controlled to control the ambient airflow through the airflow control valve 360.

[0050]

[0048] Referring to Figure 7A, a cooling tower 402 is provided which includes a plume mitigation system 400, which includes components similar to those of the cooling tower 12 shown in Figure 1 (similar reference numerals refer to similar components). The plume mitigation system 400 may include a controller 410 having a memory 412, a processor 414, and a communication circuit 416, and a plume detector 446 which may be similar to that of Figure 3.

[0051]

[0049] The cooling tower 402 may include a single fan 430, sometimes called the main fan, which extends over and around the exhaust plenum 40. The fan 430 may be operated to draw in ambient air 32 through an air inlet 431 and packing 22 and to expel exhaust air 442 out of the exhaust plenum 40 through an air outlet 433. In another approach, multiple fans (e.g., fan 30 in Figure 1) are provided to draw in ambient air 32 through packing 22 and expel exhaust air 442 out of the exhaust plenum 40. In yet another approach, one or more fans (e.g., fan 130A in Figure 3) are provided to draw in ambient air 32 through packing 22 and expel exhaust air 442 out of the exhaust plenum 40, and one or more fans (e.g., fan 130B in Figure 3) are provided to push ambient air 452 into the exhaust plenum 40. One or more fans may be angled, as described with respect to Figure 4.

[0052]

[0050] The cooling tower 402 may further include one or more louvers or dampers 460 at the base of the cooling tower 402, which can be adjusted to allow additional ambient air 462 to be drawn into the exhaust plenum by the fan 430. A damper motor 464 may be provided to adjust the position of the damper 460 via a damper coupling 466. The damper 460 may be positioned on the floor or raised portion 470 of the chilled water tank 34. In this way, in addition to the fan 430 drawing in ambient air 32 through the packing 22, the fan 430 may draw in additional ambient air 462 from below the drawn portion of the chilled water tank 34 and mix with the heated air downstream of the packing 22 and upstream of the air outlet 441. This allows ambient air to enter the cooling tower 402 from below, which may be advantageous in some scenarios. For example, a multi-cell cooling tower may have cooling towers that are installed side-by-side with respect to each other, so that airflow control valves cannot be installed on the sides of the cooling towers. The airflow control valve 460 allows ambient air to be introduced into the cooling tower 402 to reduce plume without increasing the height of the cooling tower 402.

[0053]

[0051] The position of the airflow control valve 460 (e.g., fully open, partially open, or fully closed) can be adjusted by the controller 410 of the cooling tower 402 to reduce plume. For example, when the cooling tower 402 is meeting the cooling demand and the fan 430 is operating at a fan speed of less than 100%, the airflow control valve motor 464 may open the airflow control valve 460 to reduce plume. One or more auxiliary ambient air fans, similar to the fan 370 in Figure 6, may be provided above or below the airflow control valve 460 to further control the amount of ambient air entering the cooling tower 402.

[0054]

[0052] Referring briefly to Figure 7B, the raised portion 470 and the airflow control valve 460 are horizontally offset from the packing 22. During operation, cooled process water falling from the packing 22 falls to the side of the raised portion 470 of the chilled water tank 34. The chilled water tank 34 includes a partition channel wall 472 that directs the water to the lower water reservoir portion 474 of the chilled water tank 34 and away from the airflow control valve 460 before the water exits the cooling tower 12 through the water outlet 476.

[0055]

[0053] Referring again to Figure 7A, the plume mitigation system 400 may further include a mixing chamber such as an external mixing chamber 480 located above the cooling tower 12 (for example, above the fan 430) to receive exhaust air 442 from the exhaust plenum 40. The external mixing chamber 480 may have straight side walls or inclined walls, as shown to function as a velocity recovery stack.

[0056]

[0054] The external mixing chamber 480 may include one or more auxiliary fans, such as a plume reduction fan 482, to introduce ambient air into the external mixing chamber 480. The plume reduction fan 482 may be positioned above fan 430 so that the plume reduction fan 482 pushes additional ambient air into the external mixing chamber 480 to mix with a mixture of heated ambient air 32 from the exhaust plenum 40 downstream of the packing 22 and additional ambient air 462. The speeds of fan 430 and the plume reduction fan 482 may be controlled independently. The external mixing chamber 480 may further include one or more air blenders or air mixers 484 within the external mixing chamber 480 to facilitate mixing of the additional ambient air and the exhaust air 442 received from the exhaust plenum 40. The air mixer 484 may be positioned above the plume mitigation fan 482, between the plume mitigation fan 482 and the upper end portion 486 of the external mixing chamber 480, so that the exhaust air 442 is mixed with additional ambient air introduced by the plume mitigation fan 482 before it leaves the cooling tower 12. In this way, during high-load periods when the airflow control valve 460 is not open and the fan 430 is operating to meet the load on the cooling tower (e.g., operating at 100% fan speed), the plume mitigation fan 482 may be operated to add ambient air into the external mixing chamber 480 to mitigate the plume.

[0057]

[0055] Referring to Figure 8, another method 401 for controlling a plume reduction system for a heat removal structure is shown. The plume reduction system may generally correspond to the plume reduction system 300 in Figure 6 or the plume reduction system 400 in Figures 7A and 7B. The heat removal structure may be a cooling tower such as the cooling tower 302 in Figure 6 or the cooling tower 402 in Figures 7A and 7B.

[0058]

[0056] Similar to method 201 in Figure 5, method 401 includes determining whether a cooling mode is activated for the cooling tower (403). When the cooling tower is activated in cooling mode, method 401 includes determining, via the control logic of controllers 310, 410, whether the temperature of the heated evaporative fluid is above a threshold temperature or threshold temperature range (405). If the heated evaporative fluid is above a threshold temperature range, method 401 includes determining whether one or more updraft fans are operating at maximum speed (407). If one or more updraft fans are not operating at maximum speed, method 401 includes increasing the speed of one or more updraft fans (409). Method 401 then returns to operation 403 and repeats if the temperature of the heated evaporative fluid is still above a threshold temperature range and all updraft fans are not operating at maximum speed.

[0059]

[0057] If the temperature of the heated evaporative fluid exceeds a threshold temperature and all rising airflow fans are operating at maximum speed, method 401 includes closing one or more ambient air volume control valves to a partially or fully closed position (411). For example, the volume control valve motor 364 in Figure 6 may adjust the position of the volume control valve 360 ​​to a partially or fully closed position via the volume control valve coupling 366, or the volume control valve motor 464 in Figures 7A and 7B may adjust the position of the volume control valve 460 to a partially or fully closed position via the volume control valve coupling 466. In this way, the cooling efficiency of the cooling tower can be improved by reducing the amount of ambient air that bypasses the evaporative heat exchanger.

[0060]

[0058] After closing the ambient airflow control valve in operation 411, method 401 may further include determining whether the cooling tower is operating in plume reduction mode and whether a plume has been detected or predicted (413). If the cooling tower is not operating in plume reduction mode, method 401 returns to operation 403. If the cooling tower is operating in plume reduction mode, the fan is operating upward at maximum fan speed, and a plume has been detected or predicted, method 401 may include increasing the speed of one or more external fans (e.g., external fan 330B in Figure 6 or plume reduction fan 482 in Figure 7A) to reduce the plume (415).

[0061]

[0059] Returning to operation 405, if the temperature of the heated evaporative fluid does not exceed the threshold temperature range, method 401 includes determining whether the temperature of the heated evaporative fluid is below the threshold temperature range (421). A fluid temperature below the threshold temperature range may indicate supercooling, and if such a determination is made, method 401 may include reducing the speed of one or more updraft fans (423).

[0062]

[0060] If the temperature of the heated evaporative fluid is not below the threshold temperature range (i.e., equal to the temperature within the threshold temperature range), method 401 includes determining whether the cooling tower is operating in plume reduction mode and whether a plume has been detected or predicted (425). If the cooling tower is not operating in plume reduction mode, method 401 returns to operation 403.

[0063]

[0061] If the cooling tower is operating in plume reduction mode and a plume is detected or predicted, method 401 includes determining whether one or more upflow fans are operating at maximum speed (427). If all upflow fans are operating at maximum speed, the additional ambient air in the exhaust plenum may reduce the cooling efficiency of the upflow fans, and therefore the airflow control valve remains closed or substantially closed. However, raised fans positioned higher than the upflow fans may reduce the plume even when the upflow fans are operating at maximum speed without reducing the cooling efficiency of the upflow fans. Therefore, if the cooling tower includes one or more raised fans, such as the external fan 130B in Figure 6 or the plume reduction fan 482 in Figure 7A, method 401 may include increasing the speed of one or more of the raised fans to further reduce the plume (429).

[0064]

[0062] If one or more updraft fans are not operating at maximum speed, method 401 may include implementing one or more plume reduction functions, such as opening one or more ambient air volume control valves to a partially or fully open position (431). For example, the volume control valve motor 364 in Figure 6 may adjust the position of the volume control valve 360 ​​to a partially or fully open position via the volume control valve coupling 366, or the volume control valve motor 464 in Figures 7A and 7B may adjust the position of the volume control valve 460 to a partially or fully open position via the volume control valve coupling 466. In this way, additional ambient air may be drawn into the exhaust plenum by the updraft fans to mix with the saturated air that has passed through the packing, thereby reducing the plume in the cooling tower.

[0065]

[0063] In one embodiment, before opening one or more ambient air volume control valves (431) while one or more updraft fans are operating below their maximum speed, method 401 may include determining whether an ambient air volume control valve (e.g., volume control valve 360 ​​in Figure 6 or volume control valve 460 in Figures 7A and 7B) is fully open (433). If the air volume control valve is fully open, method may include increasing the speed of one or more plume reduction fans (435) (including turning on one or more plume reduction fans). The plume reduction fans may generally correspond to the plume reduction fan 370 in Figure 6, and may be positioned adjacent to the volume control valve 360 ​​so that the plume reduction fan 370 pushes or draws additional ambient air 362 through the volume control valve 360 ​​into the exhaust plenum and mixes it with the heated saturated air to reduce the plume.

[0066]

[0064] Referring to Figures 9A and 9B, a steam stack 502 is provided which includes plume reduction systems 500A, 500B. The steam stack 502 can receive saturated or supersaturated air from a steam source 510 (e.g., from a steam turbine). The plume reduction systems 500A, 500B may include one or more plume reduction functions for introducing ambient air 506 into the chamber 508 of the steam stack 502. For example, the steam stack 502 in Figure 9A includes one or more plume reduction fans 504A, and the steam stack 502 in Figure 9B includes one or more ambient air volume control valves 504B into which ambient air will be drawn into the steam stack 502 by the Venturi effect. The plume reduction fans 504A may be configured to operate in a manner similar to those described with respect to the plume reduction fan 370 considered with respect to Figure 6 and / or the plume reduction fan 482 considered with respect to Figure 7A. The ambient air volume control valve 504B may be configured to operate in a manner similar to that described with respect to the ambient air volume control valve 360 ​​considered with respect to Figure 6. Alternatively, the steam stack may include both a plume reduction fan and an ambient air volume control valve, similar to the cooling tower 302 considered with respect to Figure 6.

[0067]

[0065] The plume reduction systems 500A and 500B may further include one or more auxiliary fans, such as an external fan 512. The external fan 512 may be configured to operate in a manner similar to that described with respect to the external fan 130C considered with respect to Figure 3 and / or the external fan 330B considered with respect to Figure 6. In this way, the external fan 512 may further reduce the plume 516 by mixing ambient air 506 just outside the exhaust area 514 of the vapor stack 502. The external fan 512 may be installed with a new vapor stack 502 or retrofitted to an existing vapor stack 502.

[0068]

[0066] The plume mitigation systems 500A and 500B may include a controller 520 having a memory 522, a processor 524, and a communication circuit 526, and a plume detector 546 which may be similar to that shown in Figure 3.

[0069]

[0067] In yet another approach, a plume reduction system similar to the plume reduction system 400 in Figure 7A may be provided at the top of the vapor stack 502. For example, a mixing chamber similar to the external mixing chamber 480 may be positioned above the vapor stack 502 to receive exhaust air from the exhaust plenum at the top of the vapor stack. The external mixing chamber may have straight side walls or inclined walls to act as a velocity recovery stack. The external mixing chamber may include one or more auxiliary fans similar to the plume reduction fan 482 (in addition to or instead of the fan 512) to introduce ambient air into the external mixing chamber without significantly affecting the operation of the vapor stack. An air mixer similar to the air mixer 484 may also be included to mix the vapor exhaust with fresh ambient air before releasing the mixed vapor and ambient air into the environment to reduce or remove the plume.

[0070]

[0068] Referring to Figure 10, another method 501 for controlling a plume reduction system for a heat removal structure is shown. The plume reduction system may generally correspond to the plume reduction systems 500A and 500B in Figures 9A and 9B. The heat removal structure may be a steam stack, such as the steam stack 502 in Figures 9A and 9B.

[0071]

[0069] Similar to method 201 in Figure 5, method 501 includes determining whether the vapor stack is operating (503). When the vapor stack is operating, saturated or supersaturated air may be discharged from the vapor stack, causing a plume during certain ambient conditions. If the vapor stack is operating, method 501 includes determining whether the vapor stack is operating in plume reduction mode and whether a plume is detected or anticipated (e.g., as determined or notified by controller 520) (505). If the vapor stack is operating in plume reduction mode and a plume is detected or anticipated, method includes providing ambient air into the vapor stack to reduce the plume (507). For example, a plume reduction fan 504A and / or ambient air volume control valve 504B may be operated to provide ambient air to the plenum inside the vapor stack.

[0072]

[0070] The method may further include determining whether the plume reduction device is providing the maximum volume of ambient air inside the vapor stack (509). For example, if the plume reduction fan 504A is operating at maximum speed, the plume reduction fan 504A is providing the maximum volume of ambient air. Similarly, if the ambient air volume control valve 504B is fully open, the ambient air volume control valve 504B is providing the maximum volume of ambient air. If the plume reduction device is not providing the maximum volume of ambient air, method 501 may restart in operation 507 until the plume reduction device is providing the maximum volume of ambient air. If the plume reduction device is providing the maximum volume of ambient air inside the vapor stack and there is still plume, method 501 includes increasing the volume of ambient air supplied to the plume 516 outside the vapor stack (511). For example, the speed of one or more external fans 512 in Figures 9A and 9B may be increased to further reduce the plume by mixing ambient air 506 immediately after the exhaust air is discharged into the discharge area 514 of the vapor stack 502. If ambient air cannot be added to the inside of the vapor stack by either the airflow control valve and / or the fan (for example, if the internal pressure of the vapor inside the vapor stack is too high), method 501 may control the on / off state and / or speed of the fans 512 in Figures 9A and 9B.

[0073]

[0071] Referring to Figure 11, a cooling tower 602 is provided which includes a plume mitigation system 600, which includes components similar to those of the cooling tower 12 shown in Figure 1 (similar reference numerals refer to similar components). The plume mitigation system 600 may include a controller 610 having a memory 612, a processor 614, and a communication circuit 616, and a plume detector 646 which may be similar to that of Figure 3.

[0074]

[0072] The plume reduction system 600 may include a single fan 630A, sometimes called the main fan, which spreads out over the exhaust plenum 40. Fan 630A may be operated to draw in ambient air 32 through the air inlet 631, direct the ambient air 32 through the backflow packing 22', and expel the exhaust air 642 from the exhaust plenum 40. Alternatively, multiple fans (e.g., fan 30 in Figure 1) may be provided to draw in ambient air 32 through the backflow packing 22' and expel the exhaust air 642 out of the exhaust plenum 40.

[0075]

[0073] Similar to the cooling tower 102 in Figure 3, the cooling tower 602 in Figure 11 may include one or more auxiliary fans, such as an external fan 630B, for mixing exhaust air 642 from the exhaust plenum 40 with additional ambient air 652. Mixing the additional ambient air 652 with the exhaust air 642 may reduce the temperature and moisture content of the exhaust air 642, thereby reducing or eliminating plume formation above the cooling tower 602. The external fan 630B may be movably connected to the cooling tower 602 (e.g., via a hinge 654) to allow access to components of the cooling tower 602 (e.g., for maintenance).

[0076]

[0074] The cooling tower 602 may further include one or more airflow control valves 660 that can be adjusted to allow additional ambient air 662 outside the cooling tower 602 to be drawn into the exhaust plenum 40 by the fan 630A and mixed with the heated air in the exhaust plenum 40 downstream of the backflow packing 22' and upstream of the air outlet 633. An airflow control valve motor 664 may be provided to adjust the position of the airflow control valve 660 via an airflow control valve coupling 666 connected to the airflow control valve 660. The position of the airflow control valve 660 (e.g., fully open, partially open, or fully closed) can be actuated by the controller 610 of the cooling tower 602 to reduce the plume. For example, when the cooling tower 602 is meeting the cooling demand and the fan 630A is operating at a fan speed of less than 100%, the airflow control valve motor 664 may open the airflow control valve 660 to reduce the plume.

[0077]

[0075] If additional plume reduction is desired, one or more auxiliary plume reduction fans 670 may be provided to add additional ambient air 662 to the exhaust plenum 40. The plume reduction fans 670 may be located on the exterior or interior sidewalls of the cooling tower 602 and may be positioned to rotate around a transverse axis, such as perpendicular to the rotation axis of the fan 630A. The plume reduction fans 670 may be positioned adjacent to the airflow control valve 660 and below the fan 630A so that the plume reduction fans 670 draw the additional ambient air 662 into the exhaust plenum 40 via the airflow control valve 660 before the fan 630A drives out the mixture of heated ambient air 32 and additional ambient air 662 from the exhaust plenum 40. In plume reduction mode, the airflow control valve 660 may be fully opened to reduce the plume and the plume reduction fans 670 may be turned on to add additional ambient air 662 to the exhaust plenum 40. The speed of the plume reduction fan 670 can also be controlled to control the ambient airflow through the airflow control valve 660.

[0078]

[0076] Referring to Figure 12, a cooling tower 702 is provided which includes a plume mitigation system 700, which includes components similar to those of the cooling tower 12 shown in Figure 1 (similar reference numerals refer to similar components). The plume mitigation system 700 may include a controller 710 having a memory 712, a processor 714, and a communication circuit 716, and a plume detector 746 which may be similar to that in Figure 3.

[0079]

[0077] The plume reduction system 700 may include a single fan 730A, sometimes called the main fan, which spreads out over the exhaust plenum 40. The fan 730A may be operated to draw in ambient air 32 through the air inlet 731.

[0080]

[0078] In the cooling tower 702 of Figure 12, the evaporative heat exchanger includes a meandering coil 22'' that carries the working fluid and an evaporative distribution system 749 for distributing the evaporative to the outside of the meandering coil 22''. The evaporative absorbs heat from the working fluid through the side walls of the meandering coil 22''. Some of the evaporative evaporates into water vapor, and the remaining evaporative is collected in a reservoir and recirculated to return to the evaporative distribution system 749.

[0081]

[0079] Similar to the cooling tower 102 in Figure 3, the cooling tower 702 in Figure 12 may include one or more auxiliary fans, such as an external fan 730B, for mixing the exhaust air 742 exiting the exhaust plenum 40 with additional ambient air 752. Mixing the additional ambient air 752 with the exhaust air 742 reduces the temperature and moisture content of the exhaust air 742, thereby reducing or eliminating plume formation above the cooling tower 702. The external fan 730B may be movably connected to the cooling tower 702 (e.g., via a hinge 754) to allow access to components of the cooling tower 702 (e.g., for maintenance).

[0082]

[0080] The cooling tower 702 may further include one or more adjustable airflow control valves 760 so that additional ambient air 762 outside the cooling tower 702 is drawn into the exhaust plenum 40 by the fan 730A and mixed with the heated air in the exhaust plenum 40 downstream of the meandering coil 22'' and upstream of the air outlet 733. An airflow control valve motor 764 may be provided to adjust the position of the airflow control valve 760 via an airflow control valve coupling 766 connected to the airflow control valve 760. The position of the airflow control valve 760 (e.g., fully open, partially open, or closed) may be actuated by the controller 710 of the cooling tower 702 to reduce plume. For example, when the cooling tower 702 is meeting a cooling demand and the fan 730A is operating at a fan speed of less than 100%, the airflow control valve motor 764 may open the airflow control valve 760 to reduce plume.

[0083]

[0081] If additional plume reduction is desired, one or more auxiliary plume reduction fans 770 may be provided to add additional ambient air 762 to the exhaust plenum 40. The plume reduction fans 770 may be located on the exterior or interior sidewall of the cooling tower 12 and may be configured to rotate about a transverse axis, such as perpendicular to the rotation axis of the fan 730A. The plume reduction fans 770 may be located below the fan 730A adjacent to the airflow control valve 760 so that the plume reduction fans 770 draw the additional ambient air 762 into the exhaust plenum 40 via the airflow control valve 760 before the fan 730A drives out the mixture of heated ambient air 32 and additional ambient air 762 from the exhaust plenum 40. In plume reduction mode, the airflow control valve 760 may be fully open to reduce plume and the plume reduction fans 770 may be turned on to add additional ambient air 762 to the exhaust plenum 40. The speed of the plume reduction fan 770 may also be controlled to control the ambient airflow through the airflow control valve 760.

[0084]

[0082] In this specification, method steps may be shown and described sequentially, but one or more of the shown and described steps may be omitted, repeated, performed simultaneously, and / or performed in an order different from the order shown in the figures and / or the order described herein. It will be understood that computer-readable instructions for facilitating the above-described method may be stored in various non-transient computer-readable media, as is known in the art. Those skilled in the art will recognize that a wide variety of modifications, changes, and combinations can be made with respect to the above-described examples without departing from the scope of the invention, and such modifications, changes, and combinations will be considered to be within the scope of the concept of the invention.

[0085]

[0083] The use of singular terms such as "a" and "an" is intended to cover both singular and plural unless otherwise specified herein or unless the context clearly indicates otherwise. The terms "comprising, including, containing" and "having" are to be interpreted as open-ended terms. The phrase "at least one of" as used herein is to be interpreted in a disjunctive sense. For example, the phrase "at least one of A and B" is to be intended to include A, B, or both A and B.

[0086]

[0084] Although specific embodiments of the present invention have been described, it will be understood that a number of changes and modifications will come to mind for those skilled in the art, and the present invention is intended to cover all changes and modifications that fall within the scope of the appended claims.

Claims

1. Air inlet and Air outlet and Evaporative heat exchanger, A main fan capable of directing a first ambient air into the air inlet, causing the first ambient air to interact with the evaporative heat exchanger to generate heated air, and discharging the heated air from the air outlet, A plume reduction fan, which is operable to bring a second ambient air into contact with the heated air downstream of the evaporative heat exchanger, A controller operably coupled to the main fan and the plume reduction fan, having a plume reduction mode, in which the controller operates the plume reduction fan to direct the second ambient air to the plume reduction fan so as to come into contact with the heated air, thereby cooling the heated air and reducing the plume. Includes, The controller has a cooling mode, and in the cooling mode, the controller operates the plume reduction fan in a first direction to direct the first ambient air to the air inlet, causing the first ambient air to interact with the evaporative heat exchanger, and assisting in the discharge of the heated air from the air outlet. A heat removal device in which the controller's plume reduction mode includes the controller operating the plume reduction fan in a second opposite direction to cause the second ambient air to come into contact with the heated air downstream of the evaporative heat exchanger.

2. The heat removal device according to claim 1, wherein the plume reduction fan is operable to direct the second ambient air into contact with the heated air downstream of the evaporative heat exchanger and upstream of the air outlet.

3. The plenum further includes an intermediate plenum between the evaporative heat exchanger and the air outlet. The heat removal device according to claim 1, wherein the plume reduction fan is operable to direct the second ambient air into contact with the heated air in the plenum.

4. The heat removal device according to claim 1, further comprising an external plume reduction fan that is operable to direct a third ambient air downstream of the air outlet into contact with the heated air.

5. An air inlet and Air outlet and Evaporative heat exchanger, A main fan capable of directing a first ambient air into the air inlet, causing the first ambient air to interact with the evaporative heat exchanger to generate heated air, and discharging the heated air from the air outlet, A plume reduction fan, which is operable to bring a second ambient air into contact with the heated air downstream of the evaporative heat exchanger, A controller operably coupled to the main fan and the plume reduction fan, having a plume reduction mode, in which the controller operates the plume reduction fan to direct the second ambient air to the plume reduction fan so as to come into contact with the heated air, thereby cooling the heated air and reducing the plume. Includes, The plume reduction fan is operable to direct the second ambient air downstream of the air outlet into contact with the heated air. The external structure further includes the evaporative heat exchanger located within the external structure, the air inlet allows ambient airflow into the interior of the external structure, and the air outlet allows heated air to exit the interior of the external structure. A heat removal device wherein the plume reduction fan is located outside the outer structure, and the plume reduction fan is operable to direct the second ambient air into contact with the heated air when the heated air is discharged from the air outlet.

6. An air inlet and Air outlet and Evaporative heat exchanger, A main fan capable of directing a first ambient air into the air inlet, causing the first ambient air to interact with the evaporative heat exchanger to generate heated air, and discharging the heated air from the air outlet, A plume reduction fan, which is operable to bring a second ambient air into contact with the heated air downstream of the evaporative heat exchanger, A controller operably coupled to the main fan and the plume reduction fan, having a plume reduction mode, in which the controller operates the plume reduction fan to direct the second ambient air to the plume reduction fan so as to come into contact with the heated air, thereby cooling the heated air and reducing the plume. Includes, The main fan comprises multiple main fans, and the plume reduction fan includes multiple plume reduction fans. The controller has a cooling mode, and in the cooling mode, the controller operates the main fan and the plume reduction fan in a first direction, thereby causing both the main fan and the plume reduction fan to work together to direct the first ambient air to the air inlet, to cause the first ambient air to interact with the evaporative heat exchanger, and to discharge the heated air from the air outlet. The Plume Reduction Mode of the Controller is determined by the Controller To operate the main fan in the first direction, and The plume reduction fan is operated in a second direction opposite to the first direction of the plume reduction fan, such that the plume reduction fan directs the second ambient air to come into contact with the heated air downstream of the evaporative heat exchanger. including, Heat removal equipment.

7. An air inlet and Air outlet and Evaporative heat exchanger, A main fan capable of directing a first ambient air into the air inlet, causing the first ambient air to interact with the evaporative heat exchanger to generate heated air, and discharging the heated air from the air outlet, A plume reduction fan, which is operable to bring a second ambient air into contact with the heated air downstream of the evaporative heat exchanger, A controller operably coupled to the main fan and the plume reduction fan, having a plume reduction mode, in which the controller operates the plume reduction fan to direct the second ambient air to the plume reduction fan so as to come into contact with the heated air, thereby cooling the heated air and reducing the plume. Includes, The main fan is operable to discharge the heated air from the air outlet in a first direction. A heat removal device wherein the plume reduction fan is operable to direct the second ambient air in a second direction that crosses the first direction so that it comes into contact with the heated air.

8. An air inlet, Air outlet and Evaporative heat exchanger, A main fan capable of directing a first ambient air into the air inlet, causing the first ambient air to interact with the evaporative heat exchanger to generate heated air, and discharging the heated air from the air outlet, A plume reduction fan, which is operable to bring a second ambient air into contact with the heated air downstream of the evaporative heat exchanger, A controller operably coupled to the main fan and the plume reduction fan, having a plume reduction mode, in which the controller operates the plume reduction fan to direct the second ambient air to the plume reduction fan so as to come into contact with the heated air, thereby cooling the heated air and reducing the plume. Includes, The main fan is operable to discharge the heated air from the air outlet in a first direction. The plume reduction fan is operable to direct the second ambient air in a second direction that crosses the first direction so as to come into contact with the heated air. A plenum is further provided between the aforementioned evaporative heat exchanger and the aforementioned air outlet. The main fan is operable to discharge the heated air in the plenum from the air outlet in the first direction. A heat removal device wherein the plume reduction fan is operable to direct the second ambient air in a second direction oblique to the first direction so that it comes into contact with the heated air in the plenum.

9. An air inlet, Air outlet and Evaporative heat exchanger, A main fan capable of directing a first ambient air into the air inlet, causing the first ambient air to interact with the evaporative heat exchanger to generate heated air, and discharging the heated air from the air outlet, A plume reduction fan, which is operable to bring a second ambient air into contact with the heated air downstream of the evaporative heat exchanger, A controller operably coupled to the main fan and the plume reduction fan, having a plume reduction mode, in which the controller operates the plume reduction fan to direct the second ambient air to the plume reduction fan so as to come into contact with the heated air, thereby cooling the heated air and reducing the plume. Includes, The evaporative heat exchanger is further provided with an adjustable airflow control valve located downstream and upstream of the air outlet. A heat removal device wherein the plume reduction fan is operable to direct the second ambient air through the adjustable airflow control valve into contact with the heated air.

10. The external structure is further provided, and the evaporative heat exchanger is located within the external structure. The exterior structure includes a floor having at least one adjustable airflow control valve, The heat removal device according to claim 1, wherein the plume reduction fan is operable to draw up the second ambient air through the at least one adjustable airflow control valve so that it comes into contact with the heated air downstream of the evaporative heat exchanger.

11. The heat removal apparatus according to claim 1, wherein the evaporative heat exchanger includes a heat transfer element, a liquid distribution system configured to distribute a liquid containing water to the heat transfer element, and a water reservoir for recovering the liquid.

12. A method for operating a heat removal device, The main fan is activated to direct the first ambient air to the air inlet of the heat removal device, the first ambient air is made to interact with the evaporative heat exchanger to generate heated air, and the heated air is discharged from the air outlet of the heat removal device. Determining plume formation conditions based at least partially on ambient air parameters, and In response to determining the aforementioned plume formation conditions, a plume reduction fan is activated to bring a second ambient air into contact with the heated air in order to cool the heated air and reduce the plume. Includes, The plume reduction fan is further operated in a first direction to direct the first ambient air towards the air inlet, to facilitate the interaction of the first ambient air with the evaporative heat exchanger to generate heated air, and to assist in discharging the heated air from the air outlet. A method comprising operating the plume reduction fan to direct a second ambient air into contact with the heated air, or operating the plume reduction fan in the opposite second direction to direct the second ambient air into contact with the heated air.

13. The method according to claim 12, wherein activating the plume reduction fan includes directing the second ambient air to come into contact with the heated air downstream of the evaporative heat exchanger and upstream of the air outlet of the heat removal device.

14. The method according to claim 12, wherein activating the plume reduction fan includes directing the second ambient air to come into contact with the heated air in the plenum of the heat removal device, which is upstream of the air outlet of the heat removal device.

15. The method according to claim 12, wherein activating the plume reduction fan includes directing the second ambient air to come into contact with the heated air downstream of the air outlet after the heated air has been discharged from the heat removal device.

16. The heat removal device includes an outer structure including the air inlet and the air outlet, and the evaporative heat exchanger is located within the outer structure. Operating the main fan involves directing the first ambient air through the air inlet into the interior of the outer structure, causing the first ambient air to interact with the evaporative heat exchanger to generate heated air inside the outer structure, and discharging the heated air from the air outlet. The method according to claim 12, wherein activating the plume reduction fan includes directing the second ambient air into contact with the heated air after the heated air has been discharged from the air outlet of the outer structure.

17. A method for operating a heat removal device, The main fan is activated to direct the first ambient air to the air inlet of the heat removal device, the first ambient air is made to interact with the evaporative heat exchanger to generate heated air, and the heated air is discharged from the air outlet of the heat removal device. Determining plume formation conditions based at least partially on ambient air parameters, and In response to determining the aforementioned plume formation conditions, a plume reduction fan is activated to bring a second ambient air into contact with the heated air in order to cool the heated air and reduce the plume. Includes, Operating the main fan includes discharging the heated air from the air outlet in a first direction, The method according to claim 12, wherein activating the plume reduction fan includes directing the second ambient air in a second direction that crosses the first direction to bring it into contact with the heated air.

18. The heat removal device includes a plenum located between the evaporative heat exchanger and the air outlet. Operating the main fan includes discharging the heated air from the air outlet in a first direction, The method according to claim 12, wherein activating the plume reduction fan includes directing the second ambient air in a second direction oblique to the first direction so as to bring it into contact with the heated air in the plenum.

19. A method for operating a heat removal device, The main fan is activated to direct the first ambient air to the air inlet of the heat removal device, the first ambient air is made to interact with the evaporative heat exchanger to generate heated air, and the heated air is discharged from the air outlet of the heat removal device. Determining plume formation conditions based at least partially on ambient air parameters, and In response to determining the aforementioned plume formation conditions, a plume reduction fan is activated to bring a second ambient air into contact with the heated air in order to cool the heated air and reduce the plume. Includes, The heat removal device includes an adjustable airflow control valve located downstream of the evaporative heat exchanger and upstream of the air outlet. The method according to claim 12, wherein activating the plume reduction fan includes directing the second ambient air through the adjustable airflow control valve to come into contact with the heated air.

20. The heat removal device includes a floor having at least one adjustable airflow control valve, The method according to claim 12, wherein activating the plume reduction fan includes drawing up the second ambient air through the adjustable airflow control valve so that it comes into contact with the heated air downstream of the evaporative heat exchanger.

21. Distributing a liquid containing water to the heat transfer elements of the evaporative heat exchanger, and The method according to claim 12, further comprising collecting the liquid in a reservoir.

22. A plume reduction system for a heat removal device having an evaporative heat exchanger and a main fan capable of generating an airflow to the evaporative heat exchanger and producing heated air, wherein the evaporative heat exchanger is configured to receive heated evaporative fluid at an initial temperature, and the plume reduction system is A plume reduction assembly, which is operable to cause mixing of the heated air with ambient air downstream of the evaporative heat exchanger, to cool the heated air, and to reduce plume formation, comprises a plume reduction fan. A controller operably coupled to the plume reduction assembly, having a plume reduction mode, and during the plume reduction mode, The initial temperature of the evaporating fluid is within a certain temperature range, and Determination of plume formation conditions based at least partially on ambient air parameters, In response to this, the controller and the plume reduction assembly are operated, including adjusting the operation of the plume reduction fan to cause a mixture of the heated air and the ambient air in order to cool the heated air and reduce the plume. A ploom reduction system, including...

23. The plume reduction system according to claim 22, wherein the controller that operates the plume reduction assembly includes increasing the speed of the plume reduction fan.

24. The plume reduction assembly includes an adjustable airflow control valve, The plume reduction system according to claim 22, wherein the controller that operates the plume reduction assembly includes opening the adjustable airflow control valve.

25. The controller that operates the plume reduction assembly, The initial temperature of the evaporating fluid is within the temperature range. Determination of the plume formation conditions, and The speed of the main fan is equal to or greater than the maximum speed of the main fan. The plume reduction system according to claim 22, comprising increasing the speed of the plume reduction fan in order to increase the airflow rate of the ambient air to be mixed with the heated air in response to the heating.

26. The plume reduction fan includes a first plume reduction fan capable of directing ambient air into the heat removal device downstream of the evaporative heat exchanger, and a second plume reduction fan capable of directing ambient air into the heated air after the heated air has been discharged from the heat removal device. The plume reduction system according to claim 25, wherein increasing the speed of the plume reduction fan in order to increase the airflow rate of the ambient air includes increasing the speeds of the first and second plume reduction fans.

27. The controller that operates the plume reduction assembly includes the controller causing the plume reduction fan to rotate in a first direction, The aforementioned controller The initial temperature of the evaporating fluid exceeds the temperature range, and The main fan has a speed greater than or equal to the maximum speed of the main fan. The ploom reduction system according to claim 22, configured to rotate the ploom reduction fan in a second opposite direction in response to the above.

28. The plume reduction assembly includes an adjustable airflow control valve, The controller that operates the plume reduction assembly, The initial temperature of the evaporating fluid is within the temperature range. Determination of the plume formation conditions, The main fan has a speed less than the maximum speed of the main fan, and The airflow control valve is not fully open. The plume reduction system according to claim 22, comprising opening the airflow control valve in response to the above.

29. The plume reduction assembly includes an adjustable airflow control valve, The aforementioned controller The initial temperature of the evaporating fluid exceeds the temperature range, and The main fan has a speed greater than or equal to the maximum speed of the main fan. The plume reduction system according to claim 22, configured to close the adjustable airflow control valve in response to the above.

30. The plume reduction assembly includes an adjustable airflow control valve, The aforementioned controller The initial temperature of the evaporating fluid exceeds the temperature range. The main fan has a speed greater than or equal to the maximum speed of the main fan, and Determination of the plume formation conditions, The plume reduction system according to claim 22, configured to close the adjustable airflow control valve and increase the fan speed of the plume reduction fan in response to the response.

31. The system further includes a sensor operably coupled to the controller and configured to detect the ambient air variable, The plume reduction system according to claim 22, wherein the controller is configured to determine the plume formation conditions based on the ambient air variable.

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