Water management system and method for indirect evaporative cooler

Abstract

The present application relates to a water management system and method for an indirect evaporative cooler. The indirect evaporative cooling system includes a frame, a heat exchanger core, a supply fan to move indoor return air within the heat exchanger core, and an outdoor exhaust fan supported by the frame to draw outdoor air through the heat exchanger core in a direction perpendicular to the indoor return air. The system also includes a water spray system positioned above the heat exchanger core to spray water on the heat exchanger core and a water collection and management system positioned below the heat exchanger core to collect water sprayed on the heat exchanger core. The water collection and management system includes a water basin configured to contain a fluid. The water basin is configured to include an operational water volume and a water reserve volume, the operational water volume and the water reserve volume collectively defining a total available water volume, and the water basin includes a water height setpoint defining the water reserve volume.

Description

[0001] BACKGROUND OF THE DISCLOSURE

[0002] 1. Public domain

[0003] The present disclosure relates generally to indirect evaporative cooler systems and, more particularly, to a water management system for an indirect evaporative cooler configured to spray water over a heat exchanger of the evaporative cooler and to collect water from the evaporative cooler.

[0004] 2. Discussion of Related Technologies

[0005] Indirect air evaporative cooling systems typically use outdoor air to indirectly cool the data center air when the outside temperature is below the temperature set point of the IT inlet air, which can result in significant energy savings. This system uses fans to blow cool outside air across an air-to-air heat exchanger, which in turn cools the hot data center air inside the heat exchanger, thereby completely isolating the data center air from the outside air. This heat removal method typically uses an evaporative assist device in which the outside of the air-to-air heat exchanger is sprayed with water, which allows the heat exchanger to continue its cooling operation for higher ambient temperatures or provides more economical cooling operation of the hot data center air. Indirect air evaporative cooling systems can provide cooling capacity of up to approximately 1,000 kilowatts (kW). Some units are approximately the size of a shipping container or larger. These systems are installed on the roof of a building or along the perimeter of a building.

[0006] Direct fresh air cooling of data centers is generally considered the most efficient cooling method. It is generally most effective for data centers that experience a wide range of temperature and humidity conditions. However, most data center managers are unwilling to take the risk of these higher operating temperatures and rapid changes in temperature and humidity. They also do not want to expose their data centers to contamination or other pollutants that may be present during direct air cooling. With increased density and containment practices, it is undesirable for IT equipment to operate at higher temperatures, especially in the event of a failure. When temperature and humidity thresholds are maintained within industry-recommended limits, indirect air economizers actually offer higher efficiencies than direct fresh air.

[0007] One approach to cooling large spaces, such as data centers, utilizes oversized air-to-air heat exchanger units (AHUs) mounted to one or more exterior building surfaces or on a roof. Modern AHUs contain oversized heat exchangers, for example, 10 feet long, 7 feet wide, and 7 feet high, containing nearly 2,000 heat exchanger tubes. In modern indirect evaporative cooling systems, hot IT air is drawn into the AHU, and one of two economizer operating modes is used to remove the heat. Based on the load, IT setpoint, and outdoor ambient conditions, the system automatically selects the most efficient operating mode. Indirect air-to-air economizer mode uses an air-to-air heat exchanger to transfer heat energy from the warmer data center air to the cooler outdoor air. When using evaporative cooling, a water spray system is typically used to apply a thin film of water to the heat exchange surfaces of the heat exchanger. By spraying water on the heat exchanger, the water absorbs heat within the heat exchanger and evaporates it into the outdoor air, thereby adding moisture to the air stream. This operating mode allows the data center to continue to benefit from economizer mode operation even when the air-to-air heat exchange process alone is unable to remove the data center heat load. Methods and systems are being explored for increasing the cooling efficiency of indirect evaporative cooling systems within data centers or other heat generating processes.

[0008] Overview of the Disclosure

[0009] One aspect of the present disclosure includes an indirect evaporative cooling system. In one embodiment, the system includes a frame, a heat exchanger core disposed within the frame, a supply fan supported by the frame to move indoor return air within the heat exchanger core, an outdoor exhaust fan supported by the frame to draw outdoor air through the heat exchanger core in a direction perpendicular to the indoor return air, a water spray system positioned above the heat exchanger core to spray water over the heat exchanger core, and a water collection and management system disposed within the frame below the heat exchanger core to collect water sprayed onto the heat exchanger core. The water collection and management system includes a water reservoir configured to hold a fluid. The water reservoir is configured to include an operating water volume and a water reserve volume, the operating water volume and the water reserve volume together defining a total available water volume. The water reservoir includes a water height set point to define the water reserve volume.

[0010] Embodiments of this system may also include defining the total available water volume as all the water used during system operation, defining the operating volume as the volume of water used for normal operation, and defining the water reserve volume as the amount of water remaining in the pool and the difference between the total available water volume and the operating volume. The pool may also include a discharge port positioned at the bottom of the pool, an overflow port positioned adjacent to the top of the pool, and a pump suction port. The water collection and management system may also include a pool discharge valve connected to the discharge port and configured to control the amount of water in the system. The pool may also be configured to include a discharge valve threshold, which is defined as a water height set point based on the required reserve volume and equivalent to the water volume representing a portion of the operating volume. The water collection and management system may also include an overflow channel connected to the overflow port and configured to prevent excess water in the pool. The water collection and management system may also include at least one sensor for measuring the water level in the pool and at least one sensor for quantifying water quality. The water collection and management system may also include a pump suction port positioned above the discharge port and below the overflow port. The water collection and management system may further include a pump connected to the pump suction port to force water back into the water spray system. The water collection and management system may further include a water supply having a water fill valve to supply water to the pool when the pool becomes shallow. The at least one sensor, the drain valve, the pump, and the water fill valve may be coupled to a controller to control the amount of water delivered to the pool by the water supply. The water collection and management system may further include a pool retention portion surrounding the pool to capture water discharged from the water spray system.

[0011] Another aspect of the present disclosure relates to a method for cooling IT air using an indirect evaporative cooling system. In one embodiment, the method includes: supplying indoor return air to a heat exchanger core; drawing outdoor air through the heat exchanger core in a direction perpendicular to the indoor return air; spraying water over the heat exchanger core; and collecting the water sprayed onto the heat exchanger core using a water collection and management system, the water collection and management system including a reservoir configured to hold a fluid. The reservoir is configured to include an operating water volume and a water reserve volume, the operating water volume and the water reserve volume together defining a total available water volume. The reservoir includes a water level set point to define the water reserve volume.

[0012] Embodiments of the method can also include defining a total available water volume as all water used during operation of the system, defining an operational volume as a volume of water used for normal operation, and defining a water reserve volume as an amount of water remaining in the sump and a difference between the total available water volume and the operational volume. The sump can also include a drain port positioned at a bottom of the sump, an overflow port positioned adjacent a top of the sump, a pump suction port, and a sump drain valve connected to the drain port and configured to control an amount of water within the system. The sump can also be configured to include a drain valve threshold defined as a water height setpoint based on a reserve volume needed and equivalent to a volume of water representing a portion of the operational volume. The water collection and management system can also include an overflow channel connected to the overflow port and configured to prevent excess water within the sump. The method can also include sensing a water level within the sump and a quality of water held within the sump. The method can also include pumping water back to the water spray system. The method can also include filling the sump with water as the sump becomes shallower. BRIEF DESCRIPTION OF DRAWINGS

[0013] The drawings are not intended to be to scale. In the drawings, each identical, or nearly identical, component that is illustrated in various figures is represented with a like numeral. For purposes of clarity, not every component can be called out in every drawing. In the drawings:

[0014] Figure 1 is a perspective view of an indirect evaporative cooling unit of an embodiment of the present disclosure;

[0015] Figure 2 is a perspective view of an indirect evaporative cooling unit of an embodiment of the present disclosure;

[0016] Figure 3 is a perspective view of an indirect evaporative cooling unit with its outer shell removed to show modular heat exchanger elements embodying a heat exchanger core;

[0017] Figure 4 is a perspective view of a water spray system;

[0018] Figure 5 is a perspective view of a water spray assembly showing spray nozzles of the water spray assembly;

[0019] Figure 6 is a top view of a water spray assembly showing a spray pattern;

[0020] Figure 7 is a cross-sectional view of a water spray assembly;

[0021] Figure 8 is a top view of a water spray assembly;

[0022] Figure 9is a schematic diagram of a cooling system for an indirect evaporative cooling unit; and

[0023] Figure 10 It is a side view of the pool and the pool's operating area. Detailed description

[0024] The present disclosure is not limited in its application to the details of the construction and arrangement of the parts set forth in the following description or shown in the accompanying drawings. The principles set forth in the present disclosure can be provided in other embodiments and can be practiced or implemented in various ways. In addition, the words and terms used herein are for descriptive purposes and should not be considered restrictive. The use of "including", "comprising", "having", "containing", "involving" and variations thereof in this article is intended to include the items listed thereafter and their equivalents and additional items. When specific dimensions, quantities or values ​​are provided, these should be considered with reference to the specific embodiments cited, as they can be scaled to fit other embodiments.

[0025] Embodiments of the present disclosure relate to systems and methods for delivering and recycling evaporated cooling water to a heat exchanger in a uniform and efficient manner. Over the past few years, many alternative cooling methods have been developed and adopted in an effort to provide efficient heat removal from various heat generating processes, data centers being one example of such processes. One such method that has recently gained favor is indirect evaporative cooling. This method minimizes / eliminates the need for energy intensive mechanical refrigeration. Some of the challenges of the indirect evaporative cooling process are manufacturing the evaporative cooling elements (cells), delivering the medium, such as water, to the cooling elements, and handling the water with the associated water collection and management systems of the cooling units. The current prior art uses a large number of parts and a significant amount of assembly labor. The present disclosure relates to a water spray system and a water collection and management system that together form the water management system of an indirect evaporative cooling cell.

[0026] Reference Figure 1 A typical indirect evaporative cooling system, generally designated 10, includes a heat exchanger core 12, a supply fan 14 that moves indoor return air (from a building, data center, or other heat-generating process) within the heat exchanger core, and an outdoor exhaust fan 16 that draws outdoor air through the heat exchanger core in a direction perpendicular to the indoor building return air. In one embodiment, the supply fan 14 pushes indoor air into the heat exchanger core 12, and the exhaust fan 16 exhausts scavenged outdoor air through the heat exchanger core to the surrounding environment. As the air passes through the heat exchanger core 12, heat is transferred from the indoor air to the outdoor air.

[0027] Figure 1The heat exchanger core 12 of the cooling system 10 shown in FIG is shown as being separate from the supporting frame structure. As shown, relatively cool outdoor intake air is directed to the bottom of the heat exchanger core 12 through an intake air plenum or intake air path present above the water collection and management system 18, as indicated by arrow A. The outdoor intake air travels through the heat exchanger core 12 and is exhausted by an outdoor exhaust fan 16, as indicated by arrow B, which is typically arranged above the heat exchanger core, but in some embodiments, can be positioned below the heat exchanger core. The heat exchanger core 12 is configured to remove heat from the indoor IT air directed to the heat exchanger core by a supply fan 14 positioned at a proximal end of the heat exchanger core, as indicated by arrow C. The supply fan 14 can also be positioned at the opposite end of the core, near arrow D, so that the indoor IT air is drawn through the core rather than pushing air through the core.

[0028] As the two air streams proceed through heat exchanger core 12, separated by the heat exchanger's walls, the warmer IT air, represented by arrows C and D, transfers heat to the scavenged ambient air, represented by arrows A and B. This typical air-to-air heat exchange process is, of course, not always feasible. In one embodiment, the air-to-air heat exchange process relies on the ambient air (represented by arrow A) being at a lower temperature than the room air or process air (represented by arrow C). However, if the ambient air is at a higher temperature than the process air, and its dry-bulb temperature is not as cool as the process air, an evaporative cooling process can be used instead. During the evaporative cooling process, a thin film of water is applied to the heat exchange surfaces of heat exchanger core 12, separating the process air flow and the ventilation air flow on the outside of the surface. Heat from the process air is transferred through the walls via convection and conduction and into this water film. From this point, the additional heat added to the water initiates a diffusion process from the water's surface, driving moisture into the scavenged air. This evaporation, or the change of state of water from liquid to gas, can dissipate a large amount of heat in a compact area. It can be seen, then, that effective wetting of the heat exchanger surfaces of the heat exchanger core 12 is crucial to this process and must be maintained throughout the heat exchanger. After the indoor IT air travels through the heat exchanger core 12, at the other end of the heat exchanger core, the now cooler indoor air is supplied back to the main building, data center, or other heat-generating process, as represented by arrow D.

[0029] In one embodiment, the cooling system 10 includes a water spray system 20 positioned above the heat exchanger core 12 to spray water over the heat exchanger core. A water collection and management system 18 is positioned below the heat exchanger core 12 of the heat exchanger to collect and recirculate the water sprayed onto the heat exchanger core by the water spray system 20. During operation, water is sprayed onto the heat exchanger core 12 of the cooling system 10 by the water spray system 20 to provide water for the evaporation process that will occur in the heat exchanger core. The water sprayed onto the heat exchanger core 12 of the cooling system 10 is generally supplied to the heat exchanger core at a rate that will ensure complete wetting of the heat exchanger core and generally exceeds the amount of water that evaporates from the heat exchanger core during a single cycle of water through the water spray system. The excess water helps to transport any dissolved solids or captured physical debris back to the water reservoir of the water collection and management system 18 positioned below the heat exchanger core 12. The water collection and management system 18 has a sump configured to effectively filter debris from the water supply before recirculating or redistributing it back to the water spray system 20 via a pump.

[0030] Reference Figure 2 and Figure 3 Embodiments of the present disclosure relate to an indirect evaporative cooling ("IEC") unit, generally designated 22, that includes an air-to-air heat exchanger that can also be used in an evaporative cooling mode. As shown, the IEC unit 22 includes a frame assembly, generally designated 24, having a base frame section 26 that, in one embodiment, can be secured to a suitable horizontal surface, such as a concrete slab on an adjacent building or a rooftop. Frame assembly 24 also includes a core support frame section 28 having a plurality of structural vertical posts, each designated 30, and horizontal shelf rails, each designated 32. The horizontal shelf rails are configured to support the heat exchanger core of the IEC unit 22, generally designated 34, which provides cooling in the manner described below. The core support frame section 28 also includes several, for example, three, intermediate posts 30 that are removable to allow access and maintenance of the heat exchanger core as needed. Depending on the cooling requirements of the IEC unit 22 , the number of columns 30 and rack rails 32 may vary and be configured to accommodate any number of heat exchanger cores 34 .

[0031] like Figure 2 As shown in FIG, fans, each generally designated 36, may be provided at one end of the IEC unit 22 to facilitate horizontal movement of air across the heat exchanger core 34. The fans 36 may also be positioned at the opposite end of the IEC unit 22 so that indoor IT air is drawn through the IEC unit rather than being pushed through the IEC unit. Figure 3As shown in FIG, additional fans, each indicated at 38, can be provided on top of the IEC unit 22 to facilitate vertical movement of air through the heat exchanger core 34. After the indoor IT air travels through the heat exchanger core 34 of the IEC unit 22, the cooler indoor air is supplied back to the process air at the other end of the IEC unit. Separately, relatively cooler outdoor intake air is directed to the bottom of the IEC unit 22, travels through the heat exchanger core 34, and is exhausted back to the ambient environment by fans 38 positioned above the heat exchanger core.

[0032] Water sprinkler system

[0033] In one embodiment of the present disclosure, a water spray system for an indirect evaporative cooling unit is configured to apply (spray) water to a rectangular or square pattern area, thereby reducing wasteful loss of water. The water spray system is also configured to spray water in a uniform and dispersed manner, thereby maximizing the operation of the heat exchanger within the evaporative cooling unit. The water spray system also requires significantly less vertical height for distributing water to the heat exchanger while managing debris entrained in the water and meeting the lower power pump requirements associated with the system.

[0034] Return to reference Figure 2 The IEC unit 22 also includes a water spray assembly, generally indicated at 40, which is positioned above and within the IEC unit above the heat exchanger core 34. Figure 3 38 is shown below the outdoor fan 38. As will be described in more detail below, a water spray assembly 40 is supported by the core support frame section 28 of the frame assembly 24. In the illustrated embodiment, a single water spray assembly 40 is provided to spray cooling water onto the heat exchanger core 34 positioned below. However, any number of water spray assemblies 40 may be provided depending on the size of the heat exchanger core 34 and the specific application. The water spray assembly 40 is configured to evenly distribute water to the top of the heat exchanger core 34.

[0035] Reference Figure 4The water spray assembly 40 includes a housing 42 having two end panels 44, 46 and two side panels 48, 50, which together define the end and side walls of the housing. Although the housing 42 is shown as rectangular in the drawings, the housing may be square. The housing 42 also includes several drift eliminators, each indicated at 52, positioned near the top edges of the end panels 44, 46 and side panels 48, 50 to define the upper end of the wetted area within the housing. The drift eliminators 52 are designed to capture water droplets and mist from the airflow and prevent the liquid from escaping the housing 42. As shown, the side panel 48 includes several doors, each indicated at 54, to provide access to the interior of the housing 42. The lower edges of the end panels 44, 46 and side panels 48, 50 define the lower horizontal plane of the housing 42, which opens onto the top surface of the heat exchanger core 34. The water spray assembly 40 further includes a water supply device 56 for supplying water to the spray nozzles disposed in the housing. Figure 5-7 The spray nozzle is described in more detail.

[0036] As discussed above, the drift eliminators 52 define the upper end of the housing 42, and the end panels 44, 46 and side panels 48, 50 define the vertical surfaces of the housing, with the door 54 providing access to other components located within the interior of the housing. Each drift eliminator 52 is configured to allow air to pass freely with minimal airside pressure drop, while being able to capture water droplets or mist contained in (or traveling with) the ventilation airflow to prevent this water from escaping the housing 42 and being lost from the heat exchange process. This captured water is collected in the elements of the drift eliminators and combines to form large water droplets that have sufficient mass to overcome the buoyancy effect of the ventilation airflow velocity so that they can be returned to the heat exchange core 34 by gravity.

[0037] Reference Figure 5-7The water spray assembly 40 also includes several spray nozzles, each designated 58, for spraying water onto the top or upper surface of the heat exchanger core 34. Each spray nozzle 58 is connected to a duct segment and configured to spray a uniformly distributed amount of water over a rectangular or square area of ​​the heat exchanger core 34. Each spray nozzle 58 is selected and configured to produce a flat, fan-shaped spray pattern of water droplets that are directed in a substantially horizontal manner. These droplets can be allowed to fall to the heat exchanger core 34 positioned below under the influence of gravity, or be transported by air streams of the ventilation air flow to the elements of the drift eliminator positioned above, or function in some combination of these two operating modes. In this manner, the water spray assembly 40 effectively distributes the water spray delivered from the spray nozzles 58 to the heat exchanger core 34 positioned below in a manner that is most efficient and evenly applied. Furthermore, the assembly 40 described herein, and the method of construction and arrangement of its components described herein and combined with this nearly horizontal spray pattern, allows for an extremely compact system that minimizes the overall height required to apply water in a uniform manner to the underlying heat exchanger core 34. This uniform distribution of water to the top surface of the heat exchanger core 34 allows the water to maintain uniform wetting of all heat exchange surfaces of the heat exchanger core below the top surface of the heat exchanger core, thereby maximizing the evaporation potential of the heat exchanger core and allowing for a more efficient process overall.

[0038] In the illustrated embodiment, the lower horizontal plane of the housing 42 opens onto the top surface of the heat exchanger core 34. This plane can be divided into any number of regions consisting of a plurality of rectangular or square-shaped quadrants. The number of quadrants varies depending on the capacity of each spray nozzle 58 and the heat exchange requirements of the heat exchanger core 34. As shown, in one embodiment, the surface 60 formed by the upper surface of the heat exchanger core 34 is divided into four quadrants 60a, 60b, 60c, and 60d, each of which can be bounded by a pair of spray nozzles 58. Each quadrant 60a, 60b, 60c, and 60d can be subdivided into at least two or more regions. These subdivisions include creating a series of nested triangles, each having equal or nearly equal areas. Although more than two subdivisions may be possible for specific applications, the simplest form of subdivision is to select two opposing corners of a rectangular or square quadrant to create two triangular regions within that quadrant. In one embodiment, each of these regions is composed of a right triangle and has a common line for the hypotenuse. These areas represent the water spray area for each of the spray nozzles 58 for that quadrant.For example, the spray nozzles 58 may be positioned near one point of the triangular area and oriented to spray water onto the side of the triangle opposite that point.

[0039] In one embodiment, the water spray assembly 40 includes eight spray nozzles 58 arranged to substantially cover a surface 60 defined by an upper surface of the heat exchanger core 34. In one example, a first quadrant 60a of the surface 60 of the housing 42 has two spray nozzles 58a, 58b to provide substantially full coverage over that portion of the surface. A second quadrant 60b of the surface 60 of the housing 42 has two spray nozzles 58c, 58d to provide substantially full coverage over that portion of the surface. A third quadrant 60c of the surface 60 of the housing 42 has two spray nozzles 58e, 58f to provide substantially full coverage over that portion of the surface. A fourth quadrant 60d of the surface 60 of the housing 42 has two spray nozzles 58g, 58h to provide substantially full coverage over that portion of the surface. For each quadrant, the two spray nozzles, e.g., spray nozzles 58a, 58b for quadrant 60a, are positioned on opposite corners of the quadrant to intersect at adjacent edges of the spray pattern. Thus, the eight spray nozzles 58 substantially cover the entire surface 60 of the housing 42.

[0040] Accordingly, each quadrant contains a set of at least two spray nozzles 58 that produce fan or V-shaped water sprays that will be contained almost entirely within a triangular pattern of each spray nozzle itself, but can minimally overlap adjacent edges to ensure water delivery to all areas of the quadrant. In this manner, the spray nozzle set provides substantially full coverage for the heat exchanger core 34 below.

[0041] Each spray nozzle 58 is fluidly coupled to the water supply 56 by a respective pipe segment 62a, 62b, 62c, 62d, 62e, 62f, 62g, and 62h. Each pipe segment 62a, 62b, 62c, 62d, 62e, 62f, 62g, and 62h is configured to bring water into the housing interior and transport the water around the housing interior. In the illustrated embodiment, the pipe sizing is based on a load demand methodology. Other embodiments can utilize different pipe design or construction methodologies to fluidly connect the spray nozzles 58 to the water supply 56.

[0042] Figure 6In addition, the spray pattern of the spray nozzle 58 is illustrated. In one embodiment, each spray nozzle 58 is configured to produce a flat fan-shaped spray pattern with a spray angle of 30 ° -60 ° at low pressure, such as 5-7 psig. For example, each spray nozzle 58 can be a ZLF65100 spray nozzle provided by Bex Incorporated of Ann Arbor, Michigan. As a result, each spray nozzle 58 produces a spray pattern to create a V-shaped pattern. In one embodiment, water is initially ejected from the spray nozzle 58 as a thin sheet of water, which spreads out as the sheet breaks down into larger droplets. The droplets continue to break into smaller droplets, thereby covering the area with a V-shaped pattern. The gravity and initial velocity of the water from the spray nozzle 58 affect how the droplets are dispersed onto the surface 60.

[0043] Figure 7 The height position of the spray nozzle 58 relative to the surface 60 of the housing 42 is illustrated. As shown, the spray nozzle 58 is positioned relatively close to the surface 60, and the spray is angled slightly below the horizontal plane. In this embodiment, the vertical angle is about 5.5 degrees with the horizontal baseline. In one embodiment, each individual spray nozzle can be angled downward and adjusted in height so that most of the water sprayed from the spray nozzle can be applied to the surface 60 of the heat exchanger core 34. As the air stream moves vertically through the heat exchanger core 34, only a very small amount of fine mist is carried. In this regard, the horizontal velocity of the droplets sprayed by the spray nozzle 58 should be attributed to the pressure of the fluid in the spray nozzle.

[0044] Figure 8 A piping schematic diagram of the spray nozzles 58 and piping segments 62 for the illustrated embodiment is shown. The piping segments 62 are secured to the end panels 44, 46 and side panels 48, 50 of the housing 42 by brackets and / or clips, which are secured to the panels by fasteners (e.g., screw fasteners). The piping segments 62 are fluidly connected to the water supply 56 to supply water to the spray nozzles 58 during operation.

[0045] It should be noted that the spray nozzles 58 described herein for performing the water spraying operation on the heat exchanger core 34 may be of a standard type, readily commercially available, and configured to provide a spray pattern generally described as a "flat spray," but may alternatively be characterized as a "flat spray (conical) nozzle," "flat spray (deflected) nozzle," "flat (uniform) spray nozzle," "flat (V-shaped) spray nozzle," "high impact flat spray nozzle," "washdown nozzle," or other similar terms. Regardless of any particular manufacturer's terminology, spray nozzles may be characterized by their spray pattern in which water emitted from the spray nozzle is generally confined to a unidirectional line of action from the spray nozzle tip when viewed from one orthogonal direction, and water emitted from the spray nozzle spreads out into a triangular shape as it travels away from the spray nozzle tip when viewed from another orthogonal direction. Spray nozzles can be selected for nearly any combination of necessary requirements for inlet water pressure, water flow rate, nozzle pressure drop, water drop size, orifice size, water spray angle, nozzle wear characteristics, nozzle attachment type, or other characteristics.

[0046] The components of the IEC unit can be selected to minimize pumping power required for the spray nozzle operation, target water flow rates specific to the heat exchanger core design and number of quadrants, and other desirable characteristics, such as fouling resistance and increased design life, compared to other conventional nozzles designed and marketed for the specific purpose of delivering cooling water to a heat exchanger. By utilizing a flat fan nozzle in the unique manner described herein, the water spray assembly can apply water in a nearly horizontal spray direction. The IEC unit's water spray assembly requires an absolute minimum vertical separation between the spray nozzle and the upper surface of the heat exchanger core, and allows the water droplets produced by the spray nozzle to be very evenly dispersed across the surface area of ​​the quadrant when the ventilation air flow is off or when operating at moderate air velocities of up to approximately 100 feet per minute. Furthermore, it has been demonstrated that, to accommodate higher air velocities while maintaining a similarly even dispersion of water droplets, the spray nozzle can be arranged so that there is a slightly increased separation height between the spray nozzle and the upper surface of the heat exchanger core, coupled with a slight downward tilt relative to the direction of the nozzle spray. This novel arrangement will allow the majority of the droplets from the nozzle spray to be applied evenly.

[0047] It should be observed that the water spray assembly 40 and the associated method of spraying water on the heat exchanger core 34 of the disclosed embodiments provide a very uniform distribution of water across the top surface of the heat exchanger core. By uniformly applying water to the top surface, uniform distribution of water to all heat exchange surfaces within the heat exchanger core 34 is achieved. This allows the heat exchanger core 34 to operate more efficiently and at its peak capacity when utilizing evaporative cooling mode. The water spray assembly 40 and the associated method of spraying water on the heat exchanger core 34 do not require controls or algorithms to operate.

[0048] The water spray assembly 40 and the related methods of spraying water over the heat exchanger core 34 described herein are readily repeatable and can be easily configured for use on other heat exchangers designed for air-to-air cooling or evaporative cooling purposes for process air streams. The assembly and method of water spraying described herein are not limited by the size, capacity, or type of heat exchanger as the heat exchanger is of the type designed for the process. The system and method do not rely on the exact components used for the illustrated application as similar components are available to adapt the design herein to any similar heat exchanger.

[0049] The water spray assembly 40 is compact in design. In particular, the assembly 40 requires minimal vertical space to disperse water evenly to the heat exchanger. The assembly 40 of the present disclosure is more compact in design and less expensive to implement when compared to other water spray assemblies.

[0050] Water collection and management systems

[0051] Referring to Figure 2 The IEC unit 22 also includes a water collection and management system, generally indicated at 80, disposed within the base frame section 26 of the frame assembly 24. As will be described in greater detail below, the water collection and management system 80 is configured to collect water sprayed onto the heat exchanger core 34 by the water spray assembly 40, which is located above the water collection and management system within the IEC unit 22. The water collection and management system 80 can also be provided to collect and manage condensate that drips from the heat exchanger core 34 and other auxiliary heat exchangers during operation. Referring to Figure 9 One embodiment of the water collection and management system 80 includes a water sump or drain pan 82 that serves as a primary reservoir for water used in the operation of the water collection and management system. The water sump 82 can be sized and shaped or subdivided as necessary to accommodate the form factor of the particular IEC unit 22 in which the water collection and management system 80 is installed. In one embodiment, the water sump 82 is fabricated by welding stainless steel panels. However, any suitable material or method of construction can be used for the purpose of retaining water within the reservoir.

[0052] As Figure 9As shown in FIG, the water collection and management system 80 includes a pool 82 configured to hold a fluid, such as water. A basin catch 84 surrounds the pool 82 to capture water discharged from the water spray assembly 40 onto the heat exchanger core 34 and direct the water to the pool. The pool 82 is in fluid communication with a pool drain valve 86 to control the amount of water in the system 80. The water collection and management system 80 also includes an overflow 88 to prevent excess water in the pool 82. When too much water is in the pool 82, the drain valve 86 can be opened to allow the water to flow out of the pool. A water level and conductivity sensor 90 is provided to monitor the water level and conductivity of the water in the pool 82, and the water level and conductivity sensor 90 can be coupled to the controller 64 together with the drain valve 86 to control the amount of water in the pool.

[0053] As shown, the water collection and management system 80 also includes at least one pump 92 to force water back to the water spray assembly 40. In one embodiment, the pump 92 is fluidly connected to the pool via one or more pool filters 94 to filter contaminants from the water before it is moved to the pump. Although the water collection and management system 80 is a semi-closed system, in which water sprayed by the water spray assembly 40 is collected and recycled by the water collection and management system for reuse, it is necessary to add new water to the system from time to time. In the illustrated embodiment, the water collection and management system 80 also includes a water supply having a water fill valve 96 to supply water to the pool 82 when the pool is shallow. Like the water level and conductivity sensor 90 and the drain valve 86, the pump 92 and the water fill valve 96 can be coupled to the controller 64 to control the amount of water delivered to the pool 82 via the water supply. In other embodiments, the fill valve 96 can function according to a mechanical controller (e.g., a float-activated switch), and the controller 64 can use the drain valve 86 via these devices to control the pool water level and the timing of the operation of the water fill valve 96.

[0054] In certain embodiments, there are two situations in which the water fill valve 96 of the water collection and management system 80 should operate. In one situation, the water fill valve 96 operates when it is commanded to open by the user in maintenance mode or by remote command. The command can be automatic to completely fill the water pool 82, or manual to partially or completely fill the water pool. In the other situation, the water fill valve 96 operates to fill the water pool 82 as part of an automated process.

[0055] In maintenance mode, a technician can command fill valve 96 to open as needed. If fill valve 96 is commanded open, the controller monitors pool level sensor 90 and automatically closes the fill valve once a maximum fill or "maxfill" condition is reached, or if a technician commands fill valve 96 to close sometime before this automatic stop point. During this automatically monitored period, controller 64 will prevent any actuation of drain valve 86 until the fill cycle is complete. That is, pool level sensor 90 records a reading indicating that the water reservoir is full and the maximum fill requirement has been met. (For the systems and methods described herein, the operation of fill valve 96 is assumed to be digital (on / off) in nature. That is, it is simply open or closed.)

[0056] Typically, the water fill process can begin whenever the water level in the reservoir 82 drops below a certain point, such that it reaches the customer set point determined by the provided water reserve setting. Once the fill cycle begins, the cycle can continue until it reaches its maximum fill level as determined by the water level sensor 90. Additionally, while the system 80 is in the fill cycle, the system can be configured to inhibit the initiation of drain or blowdown actions. If desired, any in-process actions can be allowed to complete first.

[0057] If water level sensor 90 does not detect a rise in the water level in sump 82 during a fill cycle, system 80 may be configured to assume that the water supply is unavailable and may maintain the fill valve in an open position so that water may be available for operation at the first possible moment.

[0058] If the water level sensor 90 reads incorrectly and indicates a lower reading than the actual water level, it's possible that the water level will never reach the maximum fill position to complete the fill cycle. In this case, the system 80 can initially assume the malfunction is due to a leak in the fill supply system. However, if the supply is present and the error is indeed due to the sensor itself, either due to a simple calibration error or other error in its operation, the system 80 can detect this condition. (In one embodiment, the system's average water consumption is approximately 2 gallons per minute ("gpm"), and the recommended fill requirement is approximately 25 gpm, with a minimum of 10 gpm.) Therefore, the water level may have reached an overflow condition and a generally constant level. Once the system 80 determines that the water level remains constant, it can be configured to: 1) update user notifications appropriately, 2) recalibrate the water level sensor 90 to indicate that the water level is at the overflow height, and 3) close the fill valve 96 and end the fill cycle. Once these actions are complete, the controller can determine whether the assumed cause is in fact correct. With the fill valve closed, it should register a slow drop in the water level in the reservoir 82 due to the 2 gpm consumption. If this is true, the system can resume normal operation. If it is not true, the system can enter a protection mode (as will be described in more detail below) and reactivate the fill valve 96 to maintain cooling operation and re-issue an error notification to the user or system monitor.

[0059] Additionally, if the water level sensor in sump 82 records a water level reading that is much higher than the known height or level of the overflow pipe positioned within sump 82 , system 80 can be configured to assume that overflow pipe 88 has a blockage and remove water from the system using main drain valve 86 .

[0060] There are two situations in which the water pump 92 can be started. In the first situation, the water pump 92 can be started if the customer issues a command in the maintenance mode, which also requires verifying the water level set point for starting the pump using the water level sensor 90 or by remote command. In the other situation, the water pump 92 can be started if it is commanded to enter the wetting mode from another operating mode during the automatic operation process of the system 80 under the command of the controller 64.

[0061] The desired water level in the reservoir 82 can be configurable in the system 80 and have a minimum allowable setting and a maximum allowable setting. The minimum allowable setting is based on the physical constraints of the system 80 and, for the current design, is defined as 2.5 inches (63.5 millimeters ("mm") above the suction inlet of the pump 92. This is equivalent to a water level height ("hw") of 12.7 inches (313.7 mm) in the reservoir 82. In other embodiments, the desired water level in the reservoir need only be positioned sufficiently to ensure that the operation of the pump 92 is not hindered in any way. This function is specifically determined by the requirements for the pump 92, the configuration of the reservoir 80, and the fluid connection method.

[0062] The maximum allowable setting is also based on the physical constraints of the system 80. For the disclosed configuration, the maximum allowable setting is defined as 12 mm less than the maximum fill level of the pool 82. This corresponds to a water level height ("hw" or "hwater") of 14.35 inches (364.5 mm) in the pool 82.

[0063] In one embodiment, the default value of the water level height (hw) of the sump 82 programmed into the controller 64 may be 13.6 inches (345.1 mm).

[0064] During the priming operation of pump 92, when system 80 requests the pump to start, it should not allow the blowdown cycle to operate until the pump has been primed and the first fill cycle has been completed. (For example, the water level in reservoir 82 has reached the maximum fill setting at least once, and the water pressure switch has been activated and indicates normal system operation.) In the present disclosure, the term "blowdown" cycle is used to indicate a condition in which the water or fluid contained within system 80 has a higher concentration than desired, as monitored by conductivity sensor 90 and compared to a customer-specified set point for that condition. In normal operation of this and similar equipment, when this condition is true, system 80 should act to remove the highly concentrated water or fluid from the system using drain valve 86 and replace it with fresh water from the source via fill valve 96. Furthermore, it can be demonstrated that the simultaneous activation of two devices (i.e., drain valve 86 and fill valve 96) can force a system (such as the present system) to consume more water than is absolutely necessary to support system operation, as it can dilute the concentration of the water discharged into the drain line. Finally, and as is typical of many commercially available conductivity sensors, these types of sensors are generally more accurate in their measurements when the water or fluid being measured flows past, around, or through the sensor measurement device. As presented above, the controller 64 of the system 80 will ignore the measurements of the conductivity sensor 90 until the operation of the pump 92 can be verified via a water pressure switch or other device, thereby proving that water is flowing through the conductivity sensor 90 and its measurements should be considered sufficiently accurate for use.

[0065] In the system described herein, in one embodiment, drain valve 86 may be an electrically operated valve capable of being commanded and controlled to any position during its actuation, from fully closed to fully open. Drain valve 86 may also include features defining it as normally closed or incorporating a spring or other mechanism to force the drain valve to its normal position in the event of a power loss. There are at least four scenarios under which drain valve 86 should operate. In the first scenario, drain valve 86 may be commanded to open by the customer during maintenance mode or via remote command. In this case, the command may fully drain the pool 82 by moving the valve to 100% open, or may specify a specific open position. In the second scenario, drain valve 86 may be automatically commanded via controller 64 to initiate a full system drain. For example, a full system drain may be initiated for freeze protection or some other automated process. In the third scenario, drain valve 86 may be automatically commanded to initiate a drain of the water collection and management system 80. In the fourth scenario, drain valve 86 may be automatically commanded to open when a high water level fault mode is experienced.

[0066] If an automated process or maintenance command requires a full system drain, the drain valve 86 can be opened to a fully open position (90 degrees open). Furthermore, there can be a time delay before the drain valve 86 can be commanded to close again. This delay can be long enough, such as five minutes, to ensure that the water collection and management system 80 is completely drained after the water level sensor has stopped recording water in the system.

[0067] The water collection and management system 80 can be configured to enter the blowdown state after checking the next state. The conductivity sensor 90 takes a conductivity reading to obtain the same value as the blowdown set point provided by the customer. This can be an instantaneous reading and does not have to be a time average. Breaking through this threshold can start the process to determine the correct course of action. Once this condition has been triggered, the controller 64 can determine the current water level via the water level sensor 90 - if the current water level is below the drain valve threshold, the controller can skip the drain valve actuation and go directly to the fill water cycle. For a system that has been correctly set (programmed) by the customer, this fill water should be sufficient to dilute the pool water to below the blowdown threshold set point. In addition, this can allow the water collection and management system 80 to operate closer to the required set point for a longer period of time.

[0068] Conversely, if the current water level is above the drain valve threshold, the water collection and management system 80 can enter a drain state by actuating the drain valve to remove water with a higher concentration of dissolved minerals from the system before filling the pool with fresh water. This situation can reduce the overall water consumption of the water collection and management system 80. The drain valve threshold is discussed further below, but for real-time understanding purposes, this value is determined by the actual configuration of the system and the components used to make up the system 80. This value represents a system protection to ensure that the pump 90 can continue its operation. If the system actuates the drain valve below this threshold, it may not be able to close the drain valve quickly enough, thereby allowing more water to leave the pool, which in turn may allow the pump to ingest air—which will of course force the pump to lose its initial state and cavitate.

[0069] When blowdown is performed, the drain rate is controlled and only the water contained within the operating volume (defined further below) can be drained. Water contained within the sump 82 and designated as the "reserve volume" is not considered part of the "operating volume." The drain valve 86 is commanded to an open position, which may be equal to but typically less than 100% open, and may be closed so that the total volume of fluid removed from the sump reaches a target value.

[0070] When the water collection and management system 80 is in the fill cycle, the drain action may not be allowed to occur. The drain action and the fill action should be considered independent of each other; however, the completion of the drain action can remove just enough water from the water collection and management system 80 so that the current water level is below the fill threshold setting, thereby activating the water fill system.

[0071] Reference Figure 10 As shown, the water tank 82 includes a housing 98 configured to hold water. The housing 98 includes a drain port 100, an overflow port 102, and a pump suction port 104.

[0072] definition

[0073] Total available water volume = water reserve volume + operating volume = 106.6 gal. (Other embodiments may have different volume values.)

[0074] The total usable water volume is defined as all the water that can be used by the equipment to continue its operation in the event of a water supply failure. Or in other words, the total usable water volume is the volume of water contained in the pool above the water entry pipe of the pump at its entry point (air intake point). The total usable water volume is Figure 10 It is represented by 106.

[0075] The operating volume is defined as the volume of water used for normal operation (e.g., no failure modes present). The operating volume is a subset of the total available volume and exists above the water reserve volume. The operating volume is a variable parameter and depends on the customer set point for the water reserve time ("RT"). The operating volume is Figure 10 It is represented by 108.

[0076] The drain valve threshold ("DT") is defined as a water level set point based on the customer's desired reserve volume and, in the embodiment shown and described, corresponds to a volume of water representing a lower operating volume of 24 gallons. The primary purpose of the DT setting is to prevent the water collection and management system 80 from attempting to drain a small volume of water using a large (e.g., 2 inch diameter) drain valve 86. The drain threshold adds a layer of protection to the assumptions used to develop the algorithms described below. The drain valve threshold is set at Figure 10 It is represented by 110.

[0077] The water reserve volume is defined as the amount of water remaining in the water tank 82 and is the difference between the total available water volume 106 and the operating volume. Figure 10 It is represented by 112.

[0078] from Figure 10It should also be noted that there may be other water within the system 80 or housing 98—water that cannot be "used" by the pump as shown, but is still useful to the system. Other embodiments may reposition the pump inlet port or otherwise reshape the housing 98 to incorporate this volume into the total available water volume.

[0079] If the customer sets RT to a relatively small value that may set the lower limit of the operating volume below the minimum refill start level (as defined by the customer), then the value of DT should apply to the minimum refill start level rather than the lower limit level of the operating volume.

[0080] Each time the customer resets the water reserve time (RT), the value of DT offset should be calculated.

[0081] Assuming that the volume of any housing 98 is a known function of its shape and construction, and assuming that this volume can be determined theoretically or empirically based on the measured height of the water contained by the housing, this knowledge, used in conjunction with information about the performance of the particular drain valve 86 (which is fluidly connected to the reservoir 82), will allow the system controller 64 to be constructed in such a manner that the controller can adhere to and utilize the boundary values ​​described above.

[0082] Once the volume of water and the operation of the valve can be described mathematically, the timing of when to initiate closing of the valve can be calculated so that the total volume of water drained can be the specific desired amount.

[0083] For simplicity, the equations described above may be integrated into a lookup table for use by the controller 64 to apply the appropriate drain valve threshold (DT).

[0084] In one embodiment, the bin sizes used in the pool lookup table should be set to incremental sizes, each 5 gpm larger than the previous one. These values ​​can be multiplied by the time required to complete the drain operation, or specifically, for this embodiment, by 3 minutes. The midpoint of any particular bin should be used as the operating point. Thus, it can be appreciated that: 1) each bin represents a different amount of water to be drained, and 2) each bin has a unique value for the open position of drain valve 86, so that as the volume of water to be drained increases, the valve open position for that volume will also increase. One purpose of using multiple operating points for drain valve 86 is to attempt to mitigate physical failure of the seal of drain valve 86 over thousands of actuations. In such a situation, it is not desirable for drain valve 86 to open to exactly the same point. In another embodiment, feedback control of the timing of drain valve 86 can be applied within controller 64 based on the measurements of water level sensor 90, allowing the timing of drain valve 86 operation to be based on the dynamics of the system in real time.

[0085] If the fluid level in the sump 82 registers significantly above the overflow level, the water collection and management system 80 can be configured to assume that the overflow line has a blockage and remove water from the system using the main drain valve 86. For this to occur, in the embodiment shown, the water level must exceed 224.3 gallons (d = 12.6 inches, hw = 17.4 inches). Once this occurs, the drain valve 86 can be commanded to the 50 degree open position. (Discharge rate is about 10 gpm). And once the water level drops to 186.6 gallons (d = 10.6 inches, h = 15.4 inches ) below the volume, the drain valve 86 can be commanded to start closing.

[0086] Note: d = depth measured by the water level sensor, and h = actual water height.

[0087] 50 degrees of opening is equivalent to: 50 / 90*100=55.55% opening.

[0088] If after the blowdown and fill cycle has been completed, and the conductivity reading of the sensor is still above a threshold value (eg, the customer's set point), the blowdown and fill cycle should be repeated once more.

[0089] If after this second actuation cycle the conductivity reading is still above the threshold - an alert should be issued to the system monitor / user that the equipment conductivity reading is out of calibration or requires maintenance.

[0090] In one embodiment, the water collection and management system 80 continues to drain and refill the system a total of five times in an attempt to lower the conductivity reading. If, after the fifth refill, the reading still has not dropped below the set point threshold, the water collection and management system 80 can be configured to suspend the use of the blowdown cycle and enter an emergency blowdown mode. For this mode and this embodiment, the drain valve 86 should be opened to 32 degrees of openness (or a drain rate of approximately 2 gpm) and remain in this state until the alarm is reset. In this emergency blowdown mode, the filling operation can operate as normal - cycling on and off from a low set point to a high set point. It should also be noted that this drain rate is equal to the nominal evaporation rate of the equipment in use. This value is selected to enable the equipment to continue its operation and provide cooling to critical infrastructure, while also ensuring that the water in the system is not overly concentrated due to dissolved solids, at the expense of higher than normal water consumption.

[0091] During this mode of operation, and should the system 80 trigger an alarm or alarms indicating a loss of water supply, the drain valve 86 may be commanded closed until the alarm is reset, further allowing cooling operation of the equipment to continue for the longest possible time.

[0092] In one embodiment, the actuator of the drain valve 86 includes a feedback sensor designed to report the actual valve position. If the controller does not instruct the valve 86 to close after the appropriate closing time has elapsed, or if the controller recognizes that the feedback signal has not changed appropriately during the valve closing time, the water collection and management system 80 assumes that material (debris) has become lodged in the ball valve and should take the following corrective action.

[0093] In certain embodiments, the water collection and management system 80 is configured to check / infer the valve angular position at any "stuck" position. From this position, the controller can attempt to clear the debris three times (3 times) by opening the valve in increments of five degrees per attempt. In other words, the valve can be opened five degrees from the stuck position on the first attempt, ten degrees from the stuck position on the second attempt, and fifteen degrees from the stuck position on the third attempt. After each opening, the valve should attempt to close, and only after it is proven that the valve cannot be completely closed should the next attempt be made. When this occurs, the fill cycle can be allowed to operate.

[0094] It should be noted that a commonly constructed ball valve is effectively closed at a position slightly greater than zero degrees open. Although dependent on precise manufacturing, for many ball valves, the valve is effectively closed if the valve is less than eight degrees from fully closed.

[0095] If the valve fails to fully close after the third attempt, the water collection and management system 80 can be configured to enter a conservation mode to attempt to conserve the water in the tank. For this embodiment, the water collection and management system 80 will operate in a manner similar to that described above and attempt to drive the valve to a 32-degree open position for a controlled discharge rate. (These common fallback conditions should be considered acceptable for machines or control methods of the same state.) The debris control actions mentioned above can be overcome by the sewage system controller.

[0096] The function of the water level sensor 90 is critical to the successful operation of the water collection and management system 80 and represents a single point of failure that could affect nearly every decision made by the water collection and management system controller 64. In one embodiment, the water collection and management system 80 may be provided with an additional water level sensor as an option for use as a redundant sensor.

[0097] In one embodiment, the trigger points for filling system operation are the high and low water levels determined by the water level sensor. If the liquid level sensor fails, the water collection and management system 80 can use a timer to control the system. Immediately after the signal is lost, the water collection and management system 80 can attempt to protect itself by filling the water tank 82. In certain embodiments, this initial water fill cycle can assume that the filling system is operating at the minimum allowable fill rate of 10 gpm and that the water tank 82 is empty. In this embodiment, the fill valve 96 can be opened and allowed to operate for 17.5 minutes. In another embodiment, since the pump pressure switch exists and provides a good way to determine that the pump 92 is operational, if necessary, this can be used to modify the timing of the initial fill cycle from the above value to 8.6 minutes, because a minimum volume of water is required for the operation of the pump.

[0098] After the initial fill cycle has been completed, and assuming all other systems and components are operating normally, the water collection and management system 80 can be configured to perform fill cycles at regular intervals until the alarm can be reset. One assumption for this operation can be that the water collection and management system 80 consumes 2 gpm for its operation, and further that the drain valve 86 is set to an emergency drain condition and drains an additional 2 gpm from the sump 82. Thus, for example, after a 10-minute time delay, the fill valve 96 can be open for 6.67 minutes and continue in this 10 / 6.67 minute time schedule until the alarm is reset.

[0099] Furthermore, the water collection and management system 80 can be configured to preserve the water currently held in the sump 82 in the event of a malfunction of the water level sensor 90. Essentially, to implement this configuration, the water collection and management system 80 disables the ability of the sewage controller to normally open the drain valve 86. Instead, the sewage controller immediately switches to the fixed slow drain position discussed above, for example, by moving the valve to 32 degrees open ≈ 2 gpm drain rate.

[0100] If the water collection and management system 80 is already in a drain state when the water level sensor 90 fails, the water collection and management system 80 can be configured to allow the drain to complete and immediately force a fill action to occur. If the water level sensor 90 fails while the water collection and management system 80 is in the overflow state discussed above, the drain valve 86 can be configured to immediately begin closing and the system assumes the slow drain position discussed above. If the water level sensor 90 fails while the control system (e.g., controller 64) is in the debris control state discussed above, the drain valve 86 can be configured to interrupt its current operation and be commanded to the slow drain position discussed above.

[0101] The following applies to a water collection and management system 80 that is set by the customer to operate in "water-saver" mode, and if the unit switches from evaporative cooling mode to dry air-to-air cooling mode during the automatic operation process, the following applies. In this case, if the water in the sump falls below the customer's concentration set point (blowdown set point): 1) the water currently held in the sump 82 should remain in the sump rather than be drained, and 2) when switching from wet (evaporative) operation to dry (air-to-air) operation, the last known good reading of the concentration measurement while the pump 92 is running should be recorded. In addition, the sump volume should also be calculated based on the last water level reading after other system water has drained back into the sump, for example, approximately 15 seconds after the pump is turned off.

[0102] At this point, it should be noted that the physical phenomena associated with evaporation of water from any reservoir exposed to an open or semi-open environment are relatively well known—water held within the reservoir 82 will experience this phenomenon. Furthermore, the effects of any air streams on the surface of the water in the reservoir will amplify this effect. When the equipment is in dry operating mode and the water-saver option is enabled, the water collection and management system 80 should poll the water level at least once every 30 minutes and calculate the new concentration of dissolved solids in the reservoir. For this calculation, a water conductivity sensor 90 is not required and, if used, would likely provide an erroneous indication due to the rationale stated above. However, since the last known accurate reading is recorded, it is known that the total mass of dissolved solids in the water remains constant as the volume of water contained within the reservoir changes. Therefore, given a new volume of water, the concentration of dissolved solids within that volume can be calculated.

[0103] The water provided to the equipment (as a resource typically purchased by the customer) can be held in the tank 82 and the controller 64 can be used to automatically make a decision as to whether the water is still of use. In one embodiment, the decision can be made based on: 1) a set point provided by the customer for the blowdown control; 2) the quality of the water provided from the water source via the fill valve 96; 3) knowledge of the current volume of the tank 82 and the quality of the water; and 4) the maximum volume of water allowed in the tank. Using these conditions, it can be calculated what the concentration of the full tank 82 would be if the current empty volume of the tank was filled with fresh supply water from the fill valve 96. Further, this concentration of the subsequently full tank 82 can be compared to the concentration set point prior to the action to determine if the volume of water will meet or exceed the requirements provided to the controller 64. For one embodiment, it can be determined that if the current volume of water cannot be diluted to the concentration required by the customer by a single fill action, that the water in the tank 82 is no longer economical to use and can be disposed of by draining it to the drain. In another embodiment, the determination can be some percentage value of the concentration set point provided by the customer. For example, a high level set point can be 95% of the blowdown concentration level. For the illustrated embodiment, this value guarantees that if the equipment performs the action described above, the equipment can continue its operation in the evaporation mode without immediately requiring a blowdown.

[0104] As a continuation of the discussion of this calculation, it can also be shown that at the beginning of the transition from the wet mode to the dry mode process, given the information, the high level set point can be determined at that time and then converted to a critical water volume, a volume such that if the water level were to drop below this critical water volume, it should be drained. Further, as this operational state is different from the normal wet operational mode, different subroutines can be required in the programming of the controller 64, however, the controller 64 will operate normally in this mode as long as the following conditions are true:

[0105] (1) The normal wet mode blowdown and fill routines are suspended during this mode.

[0106] (2) If during this process, the water level sensor is no longer able to measure the water level of the remaining water (e.g., the water has evaporated to a point where the actual water level is below the measurement plane), the drain valve should be commanded to the fully open position to allow any remaining water to drain.

[0107] (3) Further, a timer can be incorporated into the management method. If the tank water has been stored (not used) in the tank for longer than the duration required by the customer, the tank should be drained. This allowance, unique to the customer application, treatment and use of water resources, can be used to control the progression of any biological growth in the tank.

[0108] (4) In addition, if the ambient temperature drops below the set point temperature for more than 60 seconds, the water should be drained (freeze protection).

[0109] Having thus described several aspects of at least one embodiment of the present disclosure, it will be appreciated that various variations, modifications, and improvements may readily occur to those skilled in the art. Such variations, modifications, and improvements are intended to be a part of this disclosure and are intended to be within the spirit and scope of this disclosure. Therefore, the foregoing description and accompanying drawings are merely illustrative.

Claims

1. An indirect evaporative cooling system comprising: frame; a heat exchanger core disposed within the frame; a blower supported by the frame to move indoor return air within the heat exchanger core; an outdoor exhaust fan supported by the frame for drawing outdoor air through the heat exchanger core in a direction perpendicular to the indoor return air; a water spray system positioned above the heat exchanger core to spray water over the heat exchanger core; a pump fluidly connected to the water spray system; and a water collection and management system disposed within the frame below the heat exchanger core to collect water sprayed onto the heat exchanger core, the water collection and management system comprising a water reservoir configured to contain a fluid, the water reservoir configured to include an operating water volume and a water reserve volume, the operating water volume and the water reserve volume together defining a total available water volume, the water reservoir including a water height set point defining the water reserve volume, wherein the indirect evaporative cooling system is configured to determine the operation of the pump, and wherein the water collection and management system is configured to allow a blowdown cycle to operate after determining that the pump has been primed and a first fill cycle has been completed, and wherein in the blowdown cycle, the water collection and management system functions to remove highly concentrated water from the water collection and management system using a drain valve prior to filling the sump with fresh water, and The blowdown cycle includes draining water from the water reservoir at a controlled rate by controlling a drain valve via a controller such that only water contained in the operating water volume is drained from the indirect evaporative cooling system and water contained in the water reserve volume is retained.

2. The indirect evaporative cooling system according to claim 1, wherein: The total available water volume is defined as all water used during operation of the water collection and management system, the operating water volume is defined as the volume of water used for normal operations, and the water reserve volume is defined as the amount of water remaining in the water tank and is the difference between the total available water volume and the operating water volume.

3. The indirect evaporative cooling system according to claim 2, wherein: The pool also includes a drain port positioned at the bottom of the pool, an overflow port positioned adjacent the top of the pool, and a pump suction port.

4. The indirect evaporative cooling system according to claim 3, wherein: The drain valve is connected to the drain port and is configured to control the amount of water within the water collection and management system.

5. The indirect evaporative cooling system according to claim 4, wherein: The water tank is further configured to include a drain valve threshold defined as the water level set point, the water level set point being based on a required reserve volume and equating to a water volume representing a portion of the operating water volume.

6. The indirect evaporative cooling system according to claim 4, wherein: The water collection and management system further includes an overflow channel connected to the overflow port and configured to prevent excess water in the pool.

7. The indirect evaporative cooling system according to claim 6, wherein: The water collection and management system also includes at least one sensor for measuring the water level in the tank and at least one sensor for quantifying the water quality.

8. The indirect evaporative cooling system according to claim 7, wherein: The water collection and management system also includes a pump suction port positioned above the drain port and below the overflow port.

9. The indirect evaporative cooling system according to claim 8, wherein: The pump is connected to the pump suction port to force water back to the water sprinkler system.

10. The indirect evaporative cooling system according to claim 9, wherein: The water collection and management system further includes a water supply device having a water filling valve to supply water to the pool when the pool is shallow.

11. The indirect evaporative cooling system according to claim 10, wherein: The at least one sensor, the drain valve, the pump, and the water fill valve are coupled to the controller to control the amount of water delivered to the pool by the water supply.

12. The indirect evaporative cooling system according to claim 3, wherein: The water collection and management system also includes a sump retention portion surrounding the sump to capture water discharged from the water spray system.

13. A method of cooling IT air using an indirect evaporative cooling system, the method comprising: supplying indoor return air to the heat exchanger core; drawing outdoor air through the heat exchanger core in a direction perpendicular to the indoor return air; Pump water to the water sprinkler system; spraying water over the heat exchanger core; collecting water sprayed onto the heat exchanger core by a water collection and management system, the water collection and management system comprising a water reservoir configured to contain a fluid, the water reservoir configured to include an operating water volume and a water reserve volume, the operating water volume and the water reserve volume together defining a total available water volume, the water reservoir including a water level set point defining the water reserve volume; Determine the operation of the pump; and allowing a blowdown cycle to operate after determining that the pump has been primed and a first fill cycle has been completed, wherein in the blowdown cycle the water collection and management system functions to remove highly concentrated water from the water collection and management system using a drain valve before filling the sump with fresh water, and The blowdown cycle includes draining water from the water reservoir at a controlled rate by controlling a drain valve via a controller such that only water contained in the operating water volume is drained from the indirect evaporative cooling system and water contained in the water reserve volume is retained.

14. The method according to claim 13, wherein The total available water volume is defined as all water used during operation of the water collection and management system, the operating water volume is defined as the volume of water used for normal operations, and the water reserve volume is defined as the amount of water remaining in the water tank and is the difference between the total available water volume and the operating water volume.

15. The method according to claim 13, wherein The pool also includes a drain port positioned at the bottom of the pool, an overflow port positioned adjacent the top of the pool, a pump suction port, and the drain valve connected to the drain port and configured to control the amount of water within the water collection and management system.

16. The method according to claim 15, wherein The water tank is further configured to include a drain valve threshold defined as the water level set point, the water level set point being based on a required reserve volume and equating to a water volume representing a portion of the operating water volume.

17. The method according to claim 15, wherein: The water collection and management system further includes an overflow channel connected to the overflow port and configured to prevent excess water in the pool.

18. The method of claim 17, further comprising sensing the water level within the pool and the quality of the water held within the pool.

19. The method of claim 18, further comprising pumping water back to the water spray system.

20. The method of claim 19, further comprising filling the pool with water when the pool is shallow.

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