Fan array fan section in air-handling systems

ES 2 357 516 T3

DESCRIPTION

BACKGROUND OF THE INVENTION

The present invention relates to a ventilation section of a ventilation array used in an air handling system.

Air treatment systems (also called air treatment systems) have traditionally been used to condition buildings or rooms (hereinafter referred to as "structures"). An air handling system is defined as a structure that includes components designed to work together to condition air, as part of the primary system for ventilation of structures. The air handling system can contain components such as cooling coils, heating coils, filters, humidifiers, fans, sound attenuators, controls, and other devices that function to meet the needs of the structures. The air handling system can be manufactured in a factory and brought into the structure for installation, or it can be built on site using the devices necessary to meet the operating needs of the structure. The air handling compartment 102 of the air handling system includes the inlet chamber 112 anterior to the fan inlet cone 104 and the discharge chamber 110. Inside the air handling compartment 102 is located the ventilation unit 100 (shown as an inlet cone 104, a fan 106 and a motor 108), the ventilation frame, and any accessories associated with the function of the fan (eg. (e.g., dimmers, controls, stabilization means, and associated cabinets). Inside fan 106 is a fan wheel (not shown) with at least one blade. The fan wheel has a fan wheel diameter that is measured from one side of the outer periphery of the fan wheel to the opposite side of the outer periphery of the fan wheel. The dimensions of the treatment compartment 102, such as the height, width, and length of the air passage are determined by consulting fan manufacturers' data for the type of fan selected.

FIG. 1 shows an exemplary prior art air handling system with a single fan unit 100 housed in an air handling compartment 102. For purposes of example, the fan unit 100 is shown with an inlet cone 104, a fan 106, and a motor 108. Larger structures, structures that require greater volume of air, or structures that require higher or lower temperatures have generally required a larger fan unit 100 and generally a corresponding larger air handling compartment 102.

As shown in FIG. 1, an air handling compartment 102 is essentially divided into a discharge chamber 110 and an inlet chamber 112. The combination of discharge chamber 110 and inlet chamber 112 may be referred to as the air passage path 120. Fan unit 100 may be located in discharge chamber 110, as shown, inlet chamber 112, or partially within inlet chamber 112 and partially within discharge chamber 110. The portion of the air passage path 120 in which the fan unit 100 is located may be generically referred to as the "fan section" (indicated by reference numeral 114). The size of the inlet cone 104, the size of the fan 106, the size of the motor 108, and the size of the fan frame (not shown) determine, at least partially, the length of the airway path 120. Filter banks 122 and / or cooling coils (not shown) can be added to the system either upstream or downstream of the fan units 100.

For example, a first exemplary structure that requires 23.6 m³/ sec (50,000 cubic feet per minute) air flow at a water gauge pressure of 152 mm (six (6) inches) would generally require a prior art air handling compartment 102 large enough to to accommodate a 1397 mm (55 in) impeller, a 74.5 kW (100 horsepower) motor, and a support frame. The prior art air handling compartment 102, in turn, would be approximately 2337 mm (92 inches) high by 2896 to 3734 mm (114 to 147 inches) wide and between 2692 and 2845 mm (106 to 102 inches) long. The minimum length of air handling compartment 102 and / or airway path 120 would be dictated by manufacturers' published data for a given fan type, motor size, and application. Prior art cabinet sizing guides show exemplary rules for configuring an air handling compartment 102. These rules are based on optimization, regulations, and experimentation.

For example, a second exemplary structure includes a recirculating air conditioner used in pharmaceutical and semiconductor dean rooms that require 2.3 m³/ sec (26,000 cubic feet per minute) at a water gauge pressure of 51 mm (two (2) inches). This structure would generally require a prior art air handling system with an air handling compartment 102 large enough to accommodate a 44 in. (1118 mm) impeller, 25 horsepower (18.6 kW) motor. ) and the support frame. The prior art air handling compartment 102, in turn, would be approximately 1981 mm (78 inches) high by 2515 mm (99 inches) wide and between 2388 and 2540 mm (94 to 100 inches) long. The minimum length of air handling compartment 102 and / or airway path 120 would be dictated by manufacturers' published data for a given fan type, motor size, and application. Prior art cabinet sizing guides show exemplary rules for configuring an air handling compartment 102. These rules are

ES 2 357 516 T3 based on optimization, regulation and experimentation.

These prior art air treatment systems have many problems, including the following exemplary problems:

* Because buildings (eg, structure space) are extremely expensive, the larger size of the air handling compartment 102 is extremely undesirable.

* The 100 single fan units are expensive to produce and are generally custom produced for each task.

* Single fan 100 units are expensive to operate.

* The 100 single fan units are inefficient in that they only have optimum efficiency, or efficiency peaks, during a small portion of their operating range.

* If a single fan 100 unit breaks down, there is no air conditioning at all.

* The low frequency sound of the single fan unit 100 is difficult to attenuate.

* The large mass and turbulence of the single fan unit 100 can cause undesirable vibration.

Height restrictions have forced the use of air handling systems constructed with two fan units 100 arranged horizontally, adjacent to each other. It should be noted, however, that good engineering practice is to design air conditioning cabinets and discharge chambers 110 to be symmetrical to facilitate a more uniform airflow across the width and height of the cabinet. Dual fan 100 units have been used where there is a head restriction and the unit is designed with a high aspect ratio to accommodate the desired flow rate. As shown in the Greenheck “Installation, Operation and Maintenance Manual”, if side-by-side installation is contemplated, there are specific instructions for arranging the fans such that there is at least one fan wheel diametrical space between the wheels. fan and at least half a fan wheel diameter between the fan and the walls or ceilings. The Greenheck reference even specifically states that arrangements "with less space will experience loss of performance." Typically, the air handling system and the air handling compartment 102 are designed for a uniform velocity gradient velocity of

2.5 m / sec (500 feet per minute) in the direction of the airflow. The air handling systems of the dual fan unit 100, however, still suffered significantly from the problems of the single unit embodiments. There was no recognition of advantages in increasing the number of fan units 100 from one to two. In addition, the two-fan section of the unit 100 exhibits a non-uniform speed gradient in the region following the fan unit 100 that creates an uneven airflow through the filters, coils, and sound attenuators.

It should be noted that electrical devices have taken advantage of multi-fan cooling systems. For example, US Patent No. 6,414,845 issued to Bonet uses a modular multi-fan cooling component for installation in multiple component electronics overhangs. Although some of the advantages realized in the Bonet system would be realized in the present system, there are significant differences. For example, the Bonet system is designed to facilitate the cooling of electronic components by directing the output from each fan to a specific device or area. The Bonet system would not work to direct the airflow to all devices in the direction of the general airflow. Other patents, such as US Patent No. 4,767,262 issued to Simon and US Patent No. 6,388,880 issued to El-Ghobashy et al. reveal fan arrays for use with electronics.

Even in the computer and machine industries, however, it is recommended against fans running in parallel, as they do not provide the desired results, except in low system resistance situations where the fans run on near free supply.

DE-A-197 19 507 discloses a cabinet for telecommunications engineering with a chassis frame containing at least one modular carrier designed to receive plug-in units, and a ventilation facility for cooling the plug-in units. The ventilation installation comprises at least one fan insert with several axial fans blowing vertically, which can be plugged in and integrated into the modular holder. The fan insert is located under the cross brackets of the modular carrier and has at least one plug connector at the rear, which contacts a secondary plug connector provided on the rear wiring panel.

Document EP-A-0004448 discloses a method and apparatus for the control of a static fan-cooled cooling system, such as a large diesel engine with a heat exchanger through which the air flow is carried by fans controlled by engines. To avoid wasting power to the engines, and to extend their life, all the fluid to be cooled is continuously circulated through the heat exchanger and one between a

ES 2 357 516 T3 a number of fans is activated by a sequence control system to start operation when the temperature of the fluid detected by a sensor increases, and one is turned off when the temperature decreases. The control system selects the fan each time according to criteria related to operating time. The control system can start a fan after a short delay in increasing temperature, and stop one after a significant delay in decreasing temperature.

Document WO 96/19701, which represents the closest prior art, discloses an air conditioner with two fan units operating at the same speed to provide a balanced inlet flow rate to the two fans from a common inlet chamber. The fan speed can be controlled by a controller to vary the outside air. Multiple units are provided to meet a total air requirement for a building.

BRIEF SUMMARY OF THE INVENTION

The present invention relates to an air conditioner according to claim 1.

Preferred embodiments include the features of the dependent claims.

The foregoing and other objects, features, and advantages of the invention will be more immediately understood upon consideration of the following detailed description of the invention, in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE VARIOUS VIEWS OF THE DRAWINGS

FIG. 1 is a side view of an exemplary prior art air handling system with a large single fan unit within an air handling compartment.

FIG. 2 is a side view of an exemplary fan section of an array of fans in an air handling system of the present invention, with a plurality of small fan units within an air handling compartment.

FIG. 3 is a plan or elevation view of an exemplary section of fans in a fan array in an air handling system of the present invention, with a plurality of small fan units within an air handling compartment.

FIG. 4 is a plan or elevation view of an exemplary fan section of a 5x5 fan array in an air handling system of the present invention, with a plurality of small fan units within an air handling compartment.

FIG. 5 is a plan or elevation view of an exemplary fan section of a 3x4 fan array in an air handling system of the present invention, with a plurality of small fan units within an air handling compartment.

FIG. 6 is a plan or elevation view of an exemplary fan section of a 3x3 fan array in an air handling system of the present invention, with a plurality of small fan units within an air handling compartment.

FIG. 7 is a plan or elevation view of an exemplary fan section of a 3x1 fan array in an air handling system of the present invention, with a plurality of small fan units within an air handling compartment.

FIG. 8 is a plan or elevation view of an alternate exemplary fan section of a fan array in an air handling system of the present invention, in which a plurality of small fan units are arranged in a spaced pattern array. inside an air handling compartment.

FIG. 9 is a plan or elevation view of an alternative exemplary section of fans of a fan array in an air handling system of the present invention, in which a plurality of small fan units are arranged in a panel array. ladies inside an air handling compartment.

FIG. 10 is a plan or elevation view of an alternate exemplary section of fans of an array of fans in an air handling system of the present invention, in which a plurality of small fan units are arranged in rows of a slightly array displaced within an air handling compartment.

FIG. 11 is a plan or elevation view of an alternate exemplary section of fans of an array of fans in an air handling system of the present invention, in which a plurality of small fan units are arranged in columns of a slightly array displaced within an air handling compartment.

ES 2 357 516 T3

FIG. 12 is a plan or elevation view of an exemplary fan section of a fan array in an air handling system of the present invention, operating at 52% capacity, turning on a portion of the fans and turning off a portion of the fans. the fans.

FIG. 13 is a plan or elevation view of an exemplary section of an array of 5x5 fans in an air handling system of the present invention, operating at 32% of its capacity, turning on a part of the fans and turning off a part of the fans. fans.

FIG. 14 is a side view of an alternate exemplary fan section of a fan array in an air handling system of the present invention, with a plurality of small fan staggered units within an air handling compartment.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a fan section of a fan array in an air handling system. As shown in FIGS. 2-11, the fan section of the fan array in the air handling system uses a plurality of individual single fan units 200. In a preferred embodiment, the fan units 200 are arranged in a true formation (FIGS. 3 to 7), but alternative embodiments may include, for example, alternative arrangements, such as a spaced layout (FIG. 8), a checkerboard (FIG. 9), slightly offset rows (FIG. 10), or slightly offset columns (FIG. 11). Since the present invention could be implemented with true formations and / or alternative formations, the term "formation" is considered to be broad in scope.

The fan units 200 in the fan array of the present invention can be separated by up to 20% of a fan wheel diameter. Optimal operating conditions for a closely arranged array can be found at distances as small as 30% to 60% of a fan wheel diameter. By closely spacing the fan units 200, more air can be moved in a smaller space. For example, if the fan wheels on the fan units 200 have a fan wheel diameter of 51 mm (20 inches), only a gap of 102 mm (4 inches) (20%) is needed between the outer periphery of the a fan wheel and the outer periphery of the adjacent fan wheel (or a 2-inch gap between the outer periphery of a fan wheel and an adjacent wall or ceiling).

By using smaller fan units 200 it is possible to support fan units 200 with a less intrusive structure (fan cage). This can be compared to the large fan cage that supports the prior art fan units 100 and functions as a base. This large fan cage must be large and robust enough to support the total weight of the prior art fan units 100. Due to their size and position, known fan frames cause airflow interference. In the preferred embodiment, therefore, the fan units 200 of the fan array may be supported by a frame that supports the motors 108 with minimal restriction to air flow.

As mentioned in the Background, others have tried to use the side-by-side installation of two fan units 100, arranged horizontally adjacent to each other, within an air handling system. As also mentioned in the Background, fan arrays have been used in electronic and computer assemblies. However, in the air handling systems industry, it has always been held that there must be significant spacing between horizontally arranged fan wheels and that arrangements with less space will experience performance losses. A single large fan moves all the air in a cabinet. Using two of the same fans, or slightly smaller ones, caused the air produced by one fan to interfere with the air produced by the other fan. To alleviate the interference problem, the fans had to be spaced within certain guidelines - generally providing a clear space between the fans, from a distance of at least one wheel diameter (and half a wheel diameter to an adjacent wall). ). Applying this logic, it would not have made sense to add more fans. And even if more fans had been added, the spacing would still have been at least one wheel diameter between the fans. Furthermore, in the air handling systems industry, vertically stacking the fan units would have been unthinkable, because the means of securing the fan units would not have led to such stacking (they are designed to stand only on the ground).

It should be noted that the impeller fan is the preferred fan unit 200 of the present invention. In particular, the APF-121, APF-141, APF-161 and APF-181 impeller fans (in particular the fan wheel and fan cone) have been found to be produced by Twin City Fan Companies, Ltd. of Minneapolis , Minnesota, USA, work well. The reason impeller fans perform better is that they do not produce high speed points such as those produced by axial fans and housed centrifugal fans and large impeller fans. Alternative embodiments use known fan units or fan units to be developed, which will not produce high velocity gradients in the direction of air flow. Still other, albeit less efficient, embodiments use fan units such as axial fans and / or centrifugal housed fans that have high speed points in the direction of air flow.

ES 2 357 516 T3

In the preferred embodiment, each of the fan units 200 in the fan section of the fan array in the air handling system is controlled by an array controller 300 (FIGS. 12 and 13). In a preferred embodiment, the training controller 300 can be programmed to operate the fan units 200 with maximum efficiency. In this maximum efficiency embodiment, instead of operating all of the fan units 200 at reduced efficiency, the array controller 300 turns off certain fan units 200 and operates the remaining fan units 200 at maximum efficiency. In an alternative embodiment, the fan units 200 could all operate at the same power level (eg, efficiency and / or flow rate) of operation.

Another advantage of the present invention is that the training controller 300 (which may be a variable frequency controller (VFD)) used to control the speed of the fan and therefore the speed and pressure of the flow, could be adapted for the horses. of effective braking forces of the fan section of the fan array in the air handling system. Since the efficiency of fan wall formation can be optimized over a wide range of flow velocities and pressures, the effective operating power consumed by the fan formation is significantly less than the effective operating power consumed by comparable heat treatment systems. air of the prior art, and the power of the formation controller could be reduced accordingly. The training controller 300 could be adapted to the effective power consumption of the fan training, while the controller (which may have been a variable frequency controller) in a traditional design would adapt to the maximum technical specification of the motor according to the requirements of the Electrical Code. An example of a prior art fan design supplying 23.6m³/ sec (50,000 cubic feet per minute) of air at a pressure of 64 mm (2.5 in), would require a 37.3 kW (50 horsepower) motor and a 37.3 kW (50 horsepower) controller. force). The new invention will preferably use a fourteen 1.5 kW (2 horsepower) motor array and a 22.4 kW (30 horsepower) array controller 300.

This invention solves many of the problems of prior art air handling systems, including, but not limited to, buildings, reduced production costs, reduced operating expenses, increased efficiency, improved airflow uniformity, redundancy. , advantages of sound attenuation and reduced vibration.

Controllability

As mentioned, preferably each of the fan units 200 in the fan section of the fan array in the air handling system is controlled by an array controller 300 (FIGS. 12 and 13) that can be programmed to operate the 200 fan units with maximum efficiency. In this maximum efficiency embodiment, instead of operating all of the fan units 200 at reduced efficiency, the array controller 300 is capable of turning off certain fan units 200 and operating the remaining fan units 200 at maximum efficiency. Preferably, the array controller 300 is capable of controlling the fan units 200 individually, in predetermined groupings and / or as a group as a whole.

For example, in the 5x5 fan array, such as shown in FIGS. 4, 12 and 13, a person wishing to control the formation can select the desired air volume, an air flow level, an air flow pattern and / or how many fan units 200 to turn on. Turning first to air volume, each fan unit 200 in a 5x5 array contributes 4% of the total air. In variable air volume systems, which have the most structures, only the number of 200 fan units required to meet the demand would work. A control system (which may include the training controller 300) would be used to bring the fan units 200 online (a fan unit 200 "ON") and offline (a fan unit 200 "OFF") individually. . This ability to turn the fan units 200 on and off could effectively eliminate the need for a variable frequency controller. Similarly, each fan unit 200 in a 5x5 array uses 4% of the total power and produces 4% of the airflow level. The use of a control system to bring the fan units 200 online and offline allows a user to control power usage and / or air flow. The airflow pattern can also be controlled if that is desirable. For example, depending on the system, it is possible to create an airflow pattern only around the edges of a cabinet, or air only at the top end. Finally, the individual fan units 200 can be put online and offline. This controllability can be advantageous if one or more fan units 200 are not working properly, need maintenance (eg. g., need general service) and / or need to be replaced. Troubled individual fan units 200 can be taken offline while the rest of the system remains fully functional. Once the individual fan units 200 are ready for use, they can be brought back online.

An additional advantage of putting the fan units 200 online and offline occurs when building or structure control systems require low volumes of air at relatively high pressures. In this case, the fan units 200 could be modulated to produce a stable operating point and eliminate the surge effects that sometimes annoy structure owners and maintenance personnel. The surge effect is when the system pressure is too high for the fan speed at a given volume and the fan unit 200 has a tendency to lag.

Examples of controllability are shown in FIGS. 12 and 13. In the fans section of the training

2 357 516 T3 fans in the air handling system shown in FIG. 12, the array controller 300 toggles the fan units 200 "ON" and the fan units 200 "OFF" in a first exemplary pattern, as shown, so that the entire system is set to operate at 52% of maximum. admitted air flow, but only consumes 32% of the total admitted power. These numbers are based on exemplary operations of typical fans in a structure. FIG. 13 shows the fan section of the fan array in the air handling system set to operate at 32% of the maximum allowed airflow, but only consumes 17% of the total allowed power. These numbers are based on exemplary operations of typical fans in a structure. In this embodiment, the array controller 300 creates a second exemplary pattern of "OFF" fan units 200 and "ON" fan units 200, as shown.

Estate

The fan section of the fan array in the air handling section 220 of the present invention preferably uses (between 60% and 80%) less ground than the discharge chambers 120 of the prior art (the numbers of the prior art hundred series, as shown in FIG. 1, and the 200 series numbers of the present invention, as shown in FIG. 2) in air handling systems. Comparison of the prior art (FIG. 1) and the present invention (FIG. 2) shows a graphical representation of this shortening of the airway path 120, 220. There are many reasons why the use of multiple smaller fan units 200 can reduce the length of the airway path 120, 220. For example, reducing the size of the fan unit 100, 200 and the motor 108, 208 reduces the length of the discharge chamber 110, 210. Similarly, reducing the size of the inlet cone 104, 204 reduces the length of the inlet chamber 112, 212. The length of the discharge chamber 110, 210 can also be reduced, because the air in the fan section of the fan array in the air handling system of the present invention is essentially uniform, whereas the air handling system The prior art has higher air velocity points and needs time and space to mix so that the flow rate is uniform as it exits the air handling compartment 102, 202. (This can also be described as the highest static efficiency, in that the present invention eliminates the need for downstream stabilization means of a prior art fan system because there is little or no need for a transition from high speed. at low speed). The fan section of the fan array in the air handling system enters the air from the inlet chamber 212 more evenly and more efficiently than the prior art air handling system, so that the length of the chamber 112 , 212 input can be lowered.

For comparison purposes, the first exemplary structure set forth in the Background of the Invention will be used (a structure requiring 23.6 m³/ sec (50,000 cubic feet per minute) air flow at a water gauge pressure of 152 mm (six (6) inches)). Using the first exemplary structure, an exemplary embodiment of the present invention could be served by a nominal discharge chamber 210 that is 2261 mm (89 inches) high by 4064 mm (160 inches ) wide and between 762 and 914 mm (30 inches). to 36 inches) long (compared to between 2692 and 2845 mm (106 to 112 inches) long in prior art embodiments). The discharge chamber 210 would include a fan section of a 3x4 fan array in the air handling system such as that shown in FIG. 5, with 12 units 200 fan. The space required for each exemplary fan unit 200 would be a rectangular cube approximately 24 to 30 inches (610 to 762 mm) on one side, depending on the configuration of the array. The airway path 220 is between 2235 and 3531 mm (88 to 139 inches) (compared to between 2235 and 3531 mm (88 to 139 inches) in prior art embodiments).

For comparison purposes, the second exemplary structure set forth in the Background of the Invention will be used (a structure requiring 12.3 m³/ sec (26,000 cubic feet per minute) of air flow at a water gauge pressure of 51 mm (two (2) inches)). Using the second exemplary structure, an exemplary embodiment of the present invention could be served by a nominal discharge chamber 210 that is 2134 mm (84 inches) high by 2134 mm (84 inches) wide and between 762 and 914 mm (30 to 36 inches) long (compared to between 2388 mm and 2540 mm (94 to 100 inches) long in prior art embodiments). The discharge chamber would include a fan section of a 3x3 fan array in the air handling system (such as shown in FIG. 6) with 9 fan units 200. The space required for each exemplary fan unit 200 would be a rectangular cube approximately between 610 and 762 mm (24 to 30 inches) on one side, depending on the configuration of the array. The airway path 220 is between 1067 and 1219 mm (42 to 48 inches) (compared to between 1803 and 2913 mm (71 to 95 inches) in the prior art embodiments).

Low production costs

It is generally more cost effective to construct the fan section of the fan array in the air handling system of the present invention, compared to the single fan unit 100 used in prior art air handling systems. . Part of these cost savings may be due to the fact that the individual fan units 200 of the fan array can be mass produced. Part of these cost savings may be due to the fact that it is less expensive to manufacture smaller fan units 200.

ES 2 357 516 T3

While the individual fan units 100 of the prior art were generally custom built for the specific purpose, the present invention could be implemented on a single type of fan unit 200. In alternative embodiments, there could be multiple fan units 200 with different sizes and / or powers (both inlet and outlet). The various fan units 200 could be used in a single air handling system, or each air handling system could have only one type of fan unit 200. Even when the smaller fan units 200 are custom made, the cost of producing multiple fan units 200 for a specific project is almost always less than the cost of producing a single large prior art fan unit 100 for the same project. draft. This may be due to the difficulties of producing the larger components and / or the cost of obtaining the larger components needed for the single large fan unit 100 of the prior art. These cost savings also extend to the cost of producing a smaller air handling compartment 202.

In a preferred embodiment of the invention, the fan units 200 are modular, such that the system is of the "plug and play" type. Such modular units can be implemented including the structure for interlocking on the outside of the same fan units 200. Alternatively, such modular units can be implemented using a separate structure to interlock the fan units 200. In yet another alternative embodiment, such modular units can be implemented using a grid system in which the fan units 200 can be placed.

Reduced operating expenses

The fan section of the fan array in the air handling system of the present invention is preferably less expensive to operate than prior art air handling systems due to the greater flexibility of control and fine tuning. of the operational requirements of the structure. Also, by using 200 smaller units of higher speed fans that require less low frequency noise control and less static resistance to flow.

Increased efficiency

The fan section of the fan array in the air handling system of the present invention is preferably more efficient than the prior art air handling systems, because each small fan unit 200 can operate at maximum efficiency. The system could power cycle individual fan units 200 to prevent inefficient use of specific fan units 200. It should be noted that a training controller 300 could be used to control the fan units 200. As discussed above, the array controller 30 turns off certain fan units 200 and operates the remaining fan units 200 at maximum efficiency.

Redundancy

Multiple fan units 200 add to system redundancy. If a single fan unit 200 fails, there will still be cooling. The formation controller 300 may take into account the disabled fan units 200 so that there is no noticeable depreciation in cooling or air flow rate. This feature can also be useful during maintenance, as the formation controller 300 can turn off fan units 200 that need to be kept offline, without any noticeable depreciation in cooling or airflow velocity.

Sound attenuation advantages

The high frequency sound from the small fan units 200 is easier to attenuate than the low frequency sound from the large fan unit. Because the fan wall has less low-frequency sonic energy, fewer expensive sound traps are needed to attenuate the higher-frequency sound produced by the plurality of small fan units 200 than the low-frequency sound produced by the single unit 100. of large fan. Each of the plurality of fan units 200 will operate such that acoustic waves from each unit will interact to cancel sound at certain frequencies, thus creating a quieter operating unit than prior art systems.

Reduced vibration

The multiple fan units 200 of the present invention have smaller wheels with a lower mass and create less force, due to residual imbalance, thus causing less vibration than the large fan unit. The overall vibration of multiple fan units 200 will transmit less energy to a structure, since individual fans will tend to cancel each other, due to slight differences in phase. Each fan unit 200 of the multiple fan units 200 handles a lower percentage of the total air management requirement and thus produces less turbulence in the air flow and significantly less vibration.

It should be noted that FIG. 3 shows a fan section of a 4x6 fan array in the

ES 2 357 516 T3 air handling system with twenty-four fan units 200, FIG. 4 shows a fan section of a 5x5 fan array in the air handling system with twenty-five fan units 200, FIG. 5 shows a fan section of a 3x4 fan array in the air handling system with twelve fan units 200, FIG. 6 shows a fan section of a 3x3 fan array in the air handling system with nine fan units 200, and FIG. 7 shows a fan section of a 3x1 fan array in the air handling system with three fan units 200. It should be noted that the array can be any size or dimension of more than two fan units 200. It should be noted that although the fan units 200 may be arranged in a single plane (as shown in FIG. 2), an alternative formation configuration could contain a plurality of fan units 200 that are arranged in a staggered configuration (as shown in FIG. shown in FIG. 14) in multiple planes. It should be noted that the cooling coils (not shown) could be added to the system either upstream or downstream of the fan units 200. It should be noted that although upstream of the fan units 200 is shown, the filter bank 122, 222 could be downstream.

It should be noted that an alternative embodiment would use an array of horizontally arranged fans. In other words, the embodiments shown in FIGS. 2 to 14 could be used horizontally or vertically, or in any direction perpendicular to the direction of the air flow. For example, if a vertical portion of the air duct is functioning as the air handling compartment 202, the array of fans can be arranged horizontally. This embodiment would be especially practical in the air handling compartment for a return air duct.

It should be noted that the fan section 214 can be any part of the airway path 220 in which the fan units 200 are located. For example, fan units 200 may be located in discharge chamber 210 (as shown), inlet chamber 212, or partially within inlet chamber 212 and partially within discharge chamber 210. It should also be noted that the air handling compartment 202 may be a section of an air duct.

The terms and expressions that have been used in the foregoing specification are used as terms of description and not of limitation, and are not intended to exclude equivalents of the features shown and described, or parts thereof. The scope of the invention is defined and limited only by the following claims.