HK1114163A - Fan array fan section in air-handling systems - Google Patents

Description

Fan array fan section in air conditioning system

This application is a continuation-IN-part application of patent application Ser. No. 10/806775 and entitled FAN ARRAY FAN Session IN AIR-HANDLING SYSTEM filed 3/22/2004. Patent application serial No. 10/806775 is a non-provisional application for the benefit of provisional patent application 60/554702 entitled FAN ARRAY FAN Section INAIR-HANDLING SYSTEM filed on 3.20.2004 as claimed in 35 USC Section119(e) of the united states. Patent application serial No. 10/806775 is a non-provisional application for the benefit of provisional patent application 60/554702 entitled FAN ARRAY FAN Section INAIR-HANDLING SYSTEM, filed on 3/20/2003 in accordance with the 35 USC Section119(e) of the united states. This application is a continuation-in-part application of the PCT patent application Ser. No. PCT/US2004/008578 and entitled FAN ARRAY FAN SECTION INAIR-HANDLING SYSTEM filed 3, 19, 2004. The present application is based on and claims priority from these applications, the contents of which are hereby incorporated directly by reference.

Technical Field

The present invention relates to a fan array fan section for use in an air-handling system.

Background

Air conditioning systems (also referred to as air conditioners) are conventionally used to condition buildings or rooms (also referred to as "buildings"). An air conditioning system is defined as a structure that includes components designed to work together to condition air as part of a primary system for ventilating the structure. The air conditioning system may include, for example, cooling coils, heating coils, filters, humidifiers, fans, dampers, controls, and other devices for meeting structural needs. The air conditioning system may be manufactured in a factory and transported to the building to be installed, or it may be built in place using the necessary equipment to meet the functional needs of the building. Air handling compartment 102 of the air handling system includes an inlet plenum 112 and an outlet plenum 110 prior to fan inlet cone 104. Within the air-handling compartment 102 is disposed a fan unit 100 (shown in fig. 1 and 2 as an inlet cone 104, a fan 106, and a motor 108), a fan frame, and any accessories associated with the fan function (e.g., dampers, controls, mounting devices, and associated compartments). Within the fan 106 is a fan wheel (not shown) having at least one blade. The fan wheel has a fan wheel diameter measured from one side of the outer periphery of the fan wheel to an opposite side of the outer periphery of the fan wheel. The dimensions of the process chamber 102, such as height, width, airway length, etc., are determined by consulting the fan manufacturer for the fan type selected.

Fig. 1 shows an exemplary prior art air-conditioning system having a single fan unit 100 housed in an air-conditioning compartment 102. For exemplary purposes, the fan unit 100 is shown with an inlet cone 104, a fan 106, and a motor 108. Larger buildings, buildings requiring greater air volumes, or buildings requiring higher or lower temperatures typically require larger fan units 100 and typically correspondingly larger air-handling compartments 102.

As shown in fig. 1, air-handling compartment 102 is generally divided into an exhaust plenum 110 and an intake plenum 112. The combined exhaust chamber 110 and intake chamber 112 is referred to as airway path 120. Fan unit 100 may be disposed in exhaust plenum 110 (as shown), in intake plenum 112, or partially within intake plenum 112 and partially within exhaust plenum 110. The portion of the airway path 120 in which the fan unit 100 is disposed may be generally referred to as a "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) at least partially determine the length of the airway path 120. A filter bank 122 and/or cooling coils (not shown) may be added to the system either upstream or downstream of the fan units 100.

For example, a first exemplary configuration requiring 50,000 cubic feet per minute of airflow at six (6) inches of water gage pressure typically requires the prior art air conditioning compartment 102 to be large enough to accommodate a 55 inch impeller, a 100 horsepower motor, and a support frame. The prior art air-handling compartment 102 is approximately 92 inches high, 114 to 117 inches wide, and 106 to 112 inches long. The minimum length of the air-handling compartment 102 and/or airway path 120 is dictated by published manufacturer data for a given fan type, motor size, and application. The prior art room size guidelines show exemplary rules for configuring the air-handling compartment 103. These rules are based on optimization, tuning, and experimentation.

For example, a second exemplary configuration includes a recirculation air conditioner for use in semiconductor and pharmaceutical clean rooms requiring 26,000 cubic feet per minute of air flow at two (2) inches water gage pressure. This configuration typically requires that the prior art air system have an air-handling compartment 102 large enough to accommodate a 44 inch impeller, a 25 horsepower motor, and a support frame. The prior art air-handling compartment 102 is approximately 78 inches high, 99 inches wide, and 94 to 100 inches long. The minimum length of the air-handling compartment 102 and/or airway path 120 is dictated by published manufacturer data for a given fan type, motor size, and application. The prior art room size guidelines show exemplary rules for configuring the air-handling compartment 103. These rules are based on optimization, tuning, and experimentation.

These prior art air conditioning systems have a number of problems, including the following exemplary problems:

the large size of the air-handling compartment 102 is highly undesirable because real estate (e.g., building space) is very expensive.

The individual fan units 100 are expensive to produce and are typically custom-manufactured for each job.

The single fan unit 100 is expensive to operate.

Individual fan units 100 are inefficient in that they have optimal or peak efficiency over only a small portion of their operating range.

If a single fan unit 100 fails, air conditioning can no longer be performed.

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

The high mass and turbulence of the large fan unit 100 can cause unwanted vibrations.

Height limitations have necessitated the use of air conditioning systems configured with two fan units 100 horizontally disposed adjacent to each other. It should be noted, however, that good engineering practice is to design the air-handling compartment and the exhaust compartment 110 to be symmetrical so as to facilitate more uniform airflow across the width and height of the air-handling compartment. Dual fan units 100 have been used with height limitations and have been designed with high aspect ratios to accommodate the desired flow. As shown in Greenheck, "Installation operating and Maintenance Manual," if side-by-side Installation is desired, there are specific instructions to arrange the fans so that there is at least one fan wheel diameter gap between the fan wheels and at least one half of one fan wheel diameter between the fan and the wall or roof. The Greenheck reference even specifically states the placement of "with less spacing with experience capabilities locks". Typically, the air handling system and the air handling compartment 102 are designed for flow with a uniform velocity gradient of 500 feet per minute in the direction of airflow. However, the air-conditioning system with the dual fan unit 100 still generally suffers from the problems of the single fan embodiment. By increasing the number of fan units 100 from one to two, no advantage is found. Also, the dual fan unit 100 portion exhibits a non-uniform velocity gradient in the area immediately behind the fan unit 100, which causes non-uniform airflow through the filter, coil, and silencer.

It should be noted that the electrical device has the advantages of a multiple fan cooling system. For example, U.S. patent No.6,414,845 to Bonet uses multiple fan modular cooling components for mounting in multi-component bay (bay) electronics. Although some of the advantages realized in the Bonet system will be realized in the present system, there are significant differences. For example, the Bonet system is designed to facilitate electronics cooling by directing the output from each fan to a particular device or area. The Bonet system will not be used to direct airflow to all devices in the normal direction of airflow. Other patents, such as Simon, U.S. patent No.4,767,262 and EIGhobashy, et al, U.S. patent No.6,388,880, teach fan arrays for use with electronic devices.

However, even in the computer and machine industries, it is taught that operating fans in parallel does not provide desirable results except in situations where the fans are in a low system resistance near free-running. For example, Sunon Group has such a netPage, where they show twin-shaft fans working in parallel, but specifically states that if "parallel fans" are applied to higher system drag, the enclosure has less increase in flow rate that results in parallel fan operation. An article and lanMcLeod against a similar example of the use of parallel fans is available from HighBeam Reach's library (http:// statihttp://papstplc.comFound in the article obtained.

Disclosure of Invention

The invention relates to a fan array fan section in an air-handling system. The fan array fan section includes a plurality of fan units arranged in a fan array. Each fan unit is located within a fan unit chamber/cell (cell). Each fan unit chamber/cell has at least one sound absorbing insulation surface. The separate surfaces of the fan unit chambers/cells together form a coplanar silencer. The sound waves from the fan unit that pass through the insulation surface are at least partially dissipated as they pass through the insulation surface. In a preferred embodiment, the fan unit chamber/cell is a cell having a frame supporting the insulation surface.

The present invention also relates to a fan array fan section in an air-handling system including a plurality of fan units arranged in a fan array and located within an air-handling compartment. One preferred embodiment may include an array controller programmed to operate a plurality of fan units at peak efficiency. The plurality of fan units may be arranged in a real array (a true array) configuration, a spaced pattern array (a spaced pattern array) configuration, a checkerboard array (a checker board array) configuration, a row slightly offset array (rowslly offset array) configuration, a column slightly offset array (columns) configuration, or a staggered array (a spaced array) configuration.

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

Drawings

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

FIG. 2 is a perspective view of an exemplary prior art large fan unit;

FIG. 3 is a side view of an exemplary fan array fan section in an air-handling system of the present invention having a plurality of small fan units within an air-handling compartment;

FIG. 4 is a plan or elevation view of a 4 x 6 exemplary fan array fan section in an air-handling system of the present invention having a plurality of small fan units within an air-handling compartment;

FIG. 5 is a plan or elevation view of a 5 x 5 exemplary fan array fan section in an air-handling system of the present invention having a plurality of small fan units within an air-handling compartment;

FIG. 6 is a plan or elevation view of a 3X 4 exemplary fan array fan section in an air-handling system of the present invention having a plurality of small fan units within an air-handling compartment;

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

FIG. 8 is a plan or elevation view of a 3X 1 exemplary fan array fan section in an air-handling system of the present invention having a plurality of small fan units within an air-handling compartment;

FIG. 9 is a plan or elevation view of an alternative exemplary fan array fan section in an air-handling system of the present invention wherein a plurality of small fan units are arranged in a spaced apart pattern array within an air-handling compartment;

FIG. 10 is a plan or elevation view of an alternative exemplary fan array fan section in an air-handling system of the present invention wherein a plurality of small fan units are arranged in a checkerboard array within an air-handling compartment;

FIG. 11 is a plan or elevation view of an alternative exemplary fan array fan section in an air-handling system of the present invention, wherein a plurality of small fan units are arranged in a slightly offset row array within an air-handling compartment;

FIG. 12 is a plan or elevation view of an alternative exemplary fan array fan section in an air-handling system of the present invention, wherein a plurality of small fan units are arranged in a slightly offset array in columns within an air-handling compartment;

FIG. 13 is a plan or elevation view of a 5X 5 exemplary fan array fan section in an air-handling system of the present invention operating at 52% capacity by turning some of the fans on and some of the fans off;

FIG. 14 is a plan or elevation view of a 5X 5 exemplary fan array fan section in an air-handling system of the present invention operating at 32% capacity by turning some of the fans on and some of the fans off;

FIG. 15 is a side view of an alternative exemplary fan array fan section in an air-handling system of the present invention having a plurality of staggered small fan units within an air-handling compartment;

FIG. 16 is a perspective view of an exemplary fan array using a grid system with fan units mounted therein;

FIG. 17 is a perspective view of an exemplary fan array using a grid system or modular units, each of which includes fan units mounted within its own fan unit compartment;

FIG. 18 is a cross section of an exemplary isolated grid array system or modular unit system with an interior surface made of sound absorbing material;

FIGS. 19-23 are cross-sections of exemplary isolated grid array systems or modular unit systems having interior surfaces made of sound absorbing material, showing sound wave action;

fig. 24 is a waveform diagram illustrating the principle of sound wave cancellation; and

FIG. 25 is a perspective view of an exemplary array of dampers that can be located in front of or behind a fan unit.

Detailed Description

The invention relates to a fan array fan section in an air-handling system. As shown in fig. 3-12, the fan array fan section in the air-handling system uses a plurality of individual, individual fan units 200. In a preferred embodiment, the fan units 200 are arranged in a solid array (fig. 3-7), but alternative embodiments may include alternative arrangements, such as a spaced apart pattern array (fig. 9), a checkerboard array (fig. 10), a row offset array (fig. 11), or a column offset array (fig. 12). The term "array" is meant broadly, as the invention can be practiced with real arrays and/or alternative arrays.

The fan units 200 in the fan array of the present invention may be spaced apart by as little as 20% of the fan wheel diameter. The ideal operating condition for a closely arranged array is a fan wheel diameter at a distance of 30% to 60%. By closely spacing the fan units 200, more air may enter a smaller space. For example, if the fan wheels of the fan unit 200 have a 20 inch fan wheel diameter, only 4 inches of space (20%) is required between the outer periphery of one fan wheel and the outer periphery of an adjacent fan wheel (or 2 inches of space between the outer periphery of a fan wheel and an adjacent wall or ceiling).

By using a smaller fan unit 200, the fan unit 200 can be supported with fewer intervening structures (fan frames). This can be compared to a larger fan frame that acts as a base to support the prior art fan unit 100. The larger fan frame must be large and strong enough to support the entire weight of the prior art fan unit 100. Due to their size and location, fan frames are known to interfere with airflow. In a preferred embodiment, therefore, the fan units 200 of the fan array are supported by a frame that supports the motor 108 with minimal friction to the airflow.

As mentioned in the background section, some have attempted to use a side-by-side installation of two fan units 100 arranged horizontally adjacent to each other in an air-conditioning system. As also mentioned in the background section, fan arrays have been used in electronic and computer assemblies. However, in the field of air conditioning systems, it is always necessary to have a large spacing between horizontally arranged fan wheels, and a structure with a small spacing is expensive and suffers from performance. A single large fan sends all the air into the cabinet. The use of two identical or slightly smaller fans causes the air produced by one fan to interfere with the air produced by the other fan. To address the interference problem, the fans have to be spaced apart in a particular guide line, typically providing a clearance spacing of at least the distance of one wheel diameter between the fans (and half the wheel diameter to the adjacent wall). According to this logic, no more fans can be added. Even if additional fans have been added, the space between the fans will continue to maintain at least one wheel diameter. In addition, in the field of air-handling systems, vertically stacking fan units is not surprising, since the means for securing the fan units do not facilitate such stacking (they are designed to be located only on the base plate).

Note that the blower fan is the preferred fan unit 200 of the present invention. In particular, APF-121, APF-141, APF-161, and APF-181 blower fans manufactured by TwinCity Fan Companies, Ltd. of Minneapolis, Minnesota, U.S. and having good performance are known. Blower fans work well because they do not produce high velocity points such as those produced by shaft fans and housing centrifugal fans, as well as large centrifugal fans. Alternative embodiments may use fan units to be developed that do not produce high velocity gradients in the direction of airflow. Other embodiments, although less efficient, may also be used, such as axial fans and/or centrifugal shell fans having high velocity points in the direction of airflow.

In the preferred embodiment, each fan unit 200 in the fan array fan section in the air-handling system is controlled by an array controller 300 (fig. 13 and 14). In a preferred embodiment, the array controller 300 may be programmed to operate the fan units 200 at peak efficiency. In this peak efficiency embodiment, rather than operating all of the fan units 200 at reduced efficiency, the array controller 300 turns off some of the fan units 200 and operates the remaining fan units 200 at peak efficiency. In alternative embodiments, the fan units 200 may all be operated at the same operating power level (e.g., efficiency and/or flow).

Another advantage of the present invention is that the array controller 300, which may be a Variable Frequency Drive (VFD), for controlling fan speed and thus rate and pressure, may be adapted to the brake horsepower of the fan array fan section of the air-handling system. Since the efficiency of the fan wall array can be optimized over a larger range of flow and pressure, the actual operating power consumed by the fan array is substantially less than that consumed by a comparable prior art air conditioning system, and the power of the array controller can be reduced accordingly. The array controller 300 can be adapted to the power consumption of the fan array in the case where a controller of conventional design (already with variable frequency drive) can be adapted to the highest nameplate power rating of the motor as required by electrical code. One example of a prior art fan design providing 50,000 cubic inches per minute of 2.5 inches of air pressure would require a 50 horsepower motor and a 50 horsepower controller. The present invention preferably uses fourteen 2 horsepower motor arrays and a 30 horsepower array controller 300.

The present invention solves many problems of prior art air conditioning systems including but not limited to real estate: reduced manufacturing costs, reduced operating costs, increased efficiency, improved airflow uniformity, redundancy, good damping, and reduced vibration.

Capability of control

As mentioned, each fan unit 200 in the fan array fan section in the air-handling system is preferably controlled by an array controller 300 (fig. 12 and 13) programmed to operate the fan unit 200 at peak efficiency. In this peak efficiency embodiment, rather than operating all of the fan units 200 at reduced efficiency, the array controller 300 can turn off certain fan units 200 and operate the remaining fan units 200 at peak efficiency. Preferably, the array controller 300 is capable of individually controlling the fan units 200 in predetermined groups and/or as a group as a whole.

For example, in a 5 x 5 array such as that shown in fig. 5, 13, and 14, a person wishing to control the array may select a desired amount of air, airflow level, airflow pattern, and/or number of fan units 200 operating. Looking first at the amount of air, each fan unit 200 in a 5 x 5 array contributes 4% of the total air. In a variable air volume system (which is common to most configurations), only a few fan arrays 300 are operating that need to meet demand. The control system (which may include the array controller 300) may be used to bring the fan units 200 online (on) and offline (off) respectively (off the fan units 200). The ability to switch the fan unit 200 effectively eliminates the need for variable frequency drive. Likewise, each fan unit 200 in a 5 x 5 array uses 4% of the total power and produces 4% of the airflow level. Bringing the fan units 200 online and offline using the control system enables a user to control power usage and/or airflow. The pattern of airflow may be controlled if desired. For example, depending on the system, it may be possible to take a mode where the air flow only surrounds the edges of the cabinet or there is air only at the top. Finally, the individual fan units 200 may be brought online and offline. This control capability may be advantageous when one or more fan units 200 are malfunctioning, require maintenance (e.g., require routine service), and/or require replacement. The single fan unit 200 in question may be taken offline while the remainder of the system remains fully functional. Once the individual fan units 200 are ready for use, they are brought back online.

A further advantage of turning the fan units 200 on or off is realized when the building or building control system requires a low air volume with a higher pressure. In this case, the fan unit 200 may be modularized to create a stable operating point and eliminate a surging effect (surge effect) that sometimes annoys users and maintenance personnel. The surge effect is that the system pressure is too high for a given amount of fan speed and the fan unit 200 has a possibility of entering stall (stall).

Examples of control capabilities are shown in fig. 13 and 14. In the fan array fan section of the air-handling system shown in fig. 13, the array controller 300 may turn the fan units 200 on and off in the first example mode shown, such that the entire system is set to operate at 52% of maximum rated airflow, but consumes only 32% of the total rated power. These numbers are based on exemplary typical fan operation in the architecture. Fig. 14 shows the fan array fan section in the air-handling system set to operate at 32% of maximum rated airflow, but only consuming 17% of the total rated power. These numbers are based on exemplary typical fan operation in the architecture. In this embodiment, the array controller 300 creates a second example mode of turning off the fan units 200 and turning on the fan units 200 as shown.

Real estate

The fan array fan section in the air-handling section 220 of the present invention preferably uses less (60% to 80%) real estate than the prior art discharge plenum 120 in the air-handling system (where reference numeral 100 is prior art as shown in fig. 1 and reference numeral 200 is the present invention as shown in fig. 2). In contrast to the prior art (fig. 1), the present invention (fig. 3) shows a graphical representation of shortening the air ducts 120, 220. There are many reasons for this: the use of multiple small fan units 200 may reduce the length of the air ducts 120, 220. For example, reducing the size of the fan units 100, 200 and motors 108, 208 reduces the length of the exhaust plenums 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 plenum 110, 210 is also reduced because the air from the fan array fan section of the air-handling system of the present invention is substantially uniform, whereas prior art air-handling systems have higher air velocity points and require time and space to mix so that the airflow is uniform by the time the air exits the air-handling chamber 102, 202. (this can also be described as a higher static efficiency where the present invention no longer requires a device downstream of the discharge of the prior art fan system because there is little or no need for transition from a high rate to a low rate). The fan array fan section in the air-handling system draws air from the intake plenum 212 more evenly and efficiently than in prior art air-handling systems, thereby reducing the length of the intake plenum 112, 212.

For comparison purposes, the first exemplary configuration set forth in the background of the invention (a configuration requiring 50,000 cubic feet per minute of airflow at six (6) inches water gauge pressure) was used. Using the first exemplary configuration, an exemplary embodiment of the present invention may be serviced by a nominal exhaust plenum 212 that is 89 inches tall by 160 inches wide by 30 to 36 inches long (as compared to 106 to 112 inches long for prior art embodiments). The exhaust plenum 210 includes a 3 x 4 fan array fan section in an air-handling system having 12 fan units 200 such as shown in fig. 6. The space required for each exemplary fan unit 200 would be a rectangular cube with one side of about 24 to 30 inches, depending on the array configuration. The airway path 220 is 42 to 48 inches (as compared to 88 to 139 inches in the prior art embodiment).

For comparison purposes, the second exemplary configuration set forth in the background of the invention (a configuration requiring 26,000 cubic feet per minute of air flow at two (2) inches water gauge pressure) was used. Using the second exemplary configuration, an exemplary embodiment of the present invention may be serviced by a nominal exhaust plenum 212 that is 84 inches high by 84 inches wide by 30 to 36 inches long (as compared to the 94 to 100 inches long of prior art embodiments). The exhaust plenum includes a 3 x 3 fan array fan section in an air-handling system having 9 fan units 200 (such as shown in fig. 7). The space required for each exemplary fan unit 200 would be a rectangular cube with one side of about 24 to 30 inches, depending on the array configuration. The airway path 220 is 42 to 48 inches (as compared to 71 to 95 inches in the prior art embodiment).

Reduced production costs

It is generally more cost effective to build the fan array fan section in the air-handling system of the present invention than the single fan unit 100 used in prior art air-handling systems. The cost savings are due in part to the fact that individual fan units 200 of the fan array can be mass produced. The cost savings are also due in part to the fact that it is less expensive to manufacture smaller fan units 200. Although prior art single fan units 100 are typically customized for a particular purpose, the present invention may be implemented on a single type of fan unit 200. In alternative embodiments, there may be several fan units 200 of different sizes and/or powers (input and output). Different fan units 200 may be used in a single air-handling system or each air-handling system will have only one type of fan unit 200. Even when smaller fan units 200 are customized, the cost of manufacturing a multi-fan unit 200 for a particular project is almost always lower than the cost of producing a single large prior art fan unit 100 for the same project. This is due to the difficulty of creating larger components and/or the cost of obtaining the larger components necessary for a single large prior art fan unit 100. This cost savings also extends to the cost of creating a smaller air-handling compartment 202.

In a preferred embodiment of the invention, the fan unit 200 is modular, so that the system is "plug and play". Such modular units may be implemented by including structure for interlocking on the exterior of the fan unit 200 itself. Alternatively, such modular units may be implemented using separate structures for interlocking fan units 200. In yet another alternative embodiment, such modular units may be implemented using a grid system in which fan units 200 may be placed.

Reduced operating costs

By using smaller high speed fan units 200 requiring less frequent noise control and less static resistance to airflow than prior art air-handling systems, the fan array fan section in the air-handling system of the present invention is preferably less expensive to operate due to greater control flexibility and fine tuning of structural operating requirements.

Increased efficiency

The fan array fan section in the air-handling system of the present invention is preferably more efficient than prior art air-handling systems because each small fan unit 200 can operate at peak efficiency. The system may turn the fan units 200 on and off, respectively, to prevent inefficient use of a particular fan unit 200. It should be noted that the array controller 300 may be used to control the fan units 200. As set forth above, the array controller 300 turns off certain fan units 200 and runs the remaining fan units 200 at peak efficiency.

Redundancy

The multiple fan units 200 add redundancy to the system. If a single fan unit 200 fails, there will still be cooling. The array controller 300 may consider fan units 200 that cannot be used so that there is no significant reduction in cooling or air flow. This feature is also useful during maintenance because the array controller 300 can shut down the fan units 200 that are kept offline without a significant reduction in cooling or air flow. The bypass feature discussed below uses and increases redundancy of the system.

Noise reduction advantage

The high frequency sound of the small fan unit 200 is more easily attenuated than the low frequency sound of the large fan unit. Since the fan walls have less low frequency sound energy, shorter inexpensive sound traps are needed to attenuate the higher frequency sound generated by the plurality of small fan units 200 compared to the low frequency sound generated by a single large fan unit 100. The plurality of fan units 200 are each operated such that sound waves from each unit will interact to cancel sound at a particular frequency, resulting in a quieter operating unit than prior art systems.

Reduced vibration

The multiple fan units 200 of the present invention have smaller wheels with less mass and produce less force due to residual imbalance, resulting in less vibration than large fan units. Since the individual fans tend to cancel each other out due to small phase differences, the overall vibration of the multiple-fan unit 200 will transfer less energy to the structure. Each fan unit 200 of the multiple fan units 200 manages a smaller percentage of the total air conditioning requirements and therefore produces less turbulence in the airflow and produces considerably less vibration.

Alternative embodiments

As mentioned, in a preferred embodiment of the present invention, the fan unit 200 is modular so that the system can be "plug and play". Such modular units may be implemented by including structure for interlocking on the exterior of the fan unit 200 itself. Alternatively, such modular units may be implemented using separate structures for interlocking fan units 200. In yet another alternative embodiment, such modular units may be implemented using a grid system in which fan units 200 may be placed.

Fig. 16 shows an embodiment of an exemplary grid system 230 into which fan units 200 may be placed. In this embodiment, the mesh may be located and/or secured within the air-handling compartment 202. The fan unit 200 may be located within a grid opening. One advantage of this configuration is that individual fan units 200 may be easily removed, repaired, and/or replaced. This embodiment uses an exemplary single motor mount 232, which mount 232 supports the motor 208 without interfering with the air flow around it. As shown, this exemplary motor mount 232 has a plurality of arms that mount around the fan inlet cone 204. It should be noted that the size of the grid is exemplary. The grid may be constructed with a fan unit 200 spacing of as little as 20% of the fan wheel diameter between fan units 200 in view of the present invention.

Fig. 17 shows an embodiment using a grid system or modular units 240, the grid system or modular units 240 using a separate structure (not shown) for interlocking fan units 200. In this exemplary embodiment, each of the fan units 200 is mounted on a more conventional motor mount 242 within its own fan unit chamber 244. In a preferred embodiment, the fan unit 200 and motor mount 242 are preferably suspended within their own fan unit chamber 244 such that there is an air discharge passage 246 beneath the fan unit 200 and motor mount 242. This air release passage 246 tends to improve the flow of air around the fan unit 200.

The fan unit chamber 244 shown in fig. 17 may include one or more interior surfaces or "insulating surfaces" 248 lined with sound absorbing material. Similarly, the fan unit cells 244' shown in fig. 18-23 may include one or more interior surfaces or "insulation surfaces" 248 made of sound absorbing material. Contrary to conventional industry wisdom that surfaces cannot be placed in close proximity to the fan units 200, the present invention places one or more insulation surfaces 248 at least partially around each fan unit 200 without disrupting air flow. The insulation surface 248 may include one or more of a side, a top, a bottom, a front, or a back. Exemplary types of insulation materials include, but are not limited to, conventional insulation panels (e.g., made of inorganic fiberglass (fiberglass) alone or with factory-Foil Scrim Kraft (FSK) facing or factory-service full care jacket (ASJ) or alternative insulation materials such as open cell foam) as disclosed in U.S. patent application No.10/606435, which is assigned to the assignee of the present application and the contents of which are incorporated herein by reference It is well suited for use in concert halls, lecture halls, performance art centers, libraries, hospitals, and other facilities where acoustic sensitivity is required.

Fig. 18-23 show an exemplary insulated grid system or modular unit system interior surface or "insulated surface" 248 made of sound absorbing material. In this embodiment, each fan unit cell 244' preferably has a solid frame 250, the frame 250 supporting the insulation surface 248. In a preferred embodiment, the frame will form only the edges of the cube-shaped fan unit cell 244 ', and the insulation surfaces 248 will form the sides (e.g., top, bottom, and/or sides) of the cube-shaped fan unit cell 244'. In alternative preferred embodiments, the frame may include additional structures or struts for support and/or reinforcement. Also, the insulating surface 248 of the fan unit 244' acts as a coplanar silencer. This is illustrated in fig. 19-23, where the coplanar silencer (formed by the insulation surface 248) reduces the effect of the sound waves as they travel through the insulation surface 248. For example, in fig. 19, the central fan unit 200a is loudest in its own fan unit cell 244'. As the sound of the fan propagates radially, it is at least partially consumed as it passes through the surrounding insulation surface 248. This is shown diagrammatically as the tone circle being darkest in color at the central fan unit cell 244 'and lighter in color in the surrounding fan unit cells 244'. The result is: the sound from the central fan unit 200a that ultimately emanates from the system is softer than the sound emanating from a system without a coplanar silencer. In fig. 20, the first side fan unit 200b is loudest in its own fan unit cell 244'. As the sound of the fan propagates radially, it is at least partially consumed as it passes through the surrounding insulation surface 248. This is shown diagrammatically as the tone circle being darkest in color at the central fan unit cell 244 ', lighter in color in the surrounding fan unit cells 244 ', and lighter in color in the fan unit cells 244 ' at greater distances from the original fan unit 200 b. The result is: the sound from the central fan unit 200b that ultimately emanates from the system is softer than the sound emanating from a system without a coplanar silencer. Fig. 21 shows the first side fan unit 200b, the second side fan unit 200c, and their respective sound waves. As illustrated diagrammatically in fig. 24, another principle of the invention is: the interaction of the sound waves causes the sound waves to be offset to a certain extent, so that the sound waves disappear. Fig. 24 shows a sonic wave a and an opposite sonic wave B, which are opposite each other and thus interact to form a flat-top wave a + B. If the sound waves are not exactly opposite, the combined sound wave is not flat-topped, but some sound waves are still cancelled. This is the basic sonic principle that the present invention benefits. The result of the acoustic wave cancellation is: the sound from the central fan units 200b, 200c that ultimately emanates from the system is softer than the sound emanating from a system without a coplanar silencer. Fig. 22 emphasizes the first corner fan unit 200d and its waveform. Fig. 23 emphasizes the lower corner fan unit 200d and the second corner fan unit 200e and their respective waveforms. The analysis of fig. 22 and 23 is similar to the analysis of fig. 20 and 21, respectively. It should be noted that in a preferred embodiment, more than two fans may be operating simultaneously and all operating fans will have a waveform. All of the operating fan waveforms will be able to create dissipation (as they pass through the surrounding insulation surface 248) and be cancelled by the coplanar silencer waveforms.

Although fig. 17 shows the discharge plenum 210 positioned within the fan unit plenum 244, alternative embodiments of the fan unit plenum 244 may surround the inlet plenum 212, or at least partially surround the inlet plenum 212 and the discharge plenum 210. Alternative embodiments of the fan unit chamber 244 may also have a grid or wire surfaces (which increases the safety of the present invention) or be open (which reduces cost).

Bypass feature

The multiple fan units allow the array to operate in a range from full flow to partial flow (where each fan contributes 1/N of the air flow, where N is the number of fans). The most direct drive fan systems operate at multiple speeds rather than fully synchronous motor speeds in order to match the heating or cooling needs of the structure. Speed control is typically maintained through the use of variable frequency drives. Because variable frequency drives are electronic devices, each drive operating within an air conditioning structure has a certain probability of failing. In a conventional air conditioning system, if the VFD fails, the air conditioner will either shut down or operate in a known bypass mode at full synchronous speed of the motor. In conventional systems, the fan unit in the air conditioner must be slowed down by some mechanical means in order to limit the pressure and flow to meet the needs of the building. Mechanical throttling in the bypass mode of conventional systems can create excessive noise and reduce fan efficiency. The present invention overcomes this problem by allowing the output of the fan array to be varied to meet the design point by turning certain fans off. The array can be adapted to meet flow and pressure requirements without the need for mechanical throttling and without the consequent increase in noise and decrease in efficiency.

Damper

Fig. 25 shows an array of dampers 260 that may be located in front of or behind the fan unit 200 to at least partially prevent back ventilation. In the exemplary embodiment shown, damper 260 includes a plurality of plates, each plate being located on its own pivot. In the exemplary embodiment shown, the plurality of plates slightly overlap each other. The illustrated embodiment is configured so that when air flows through the fan unit 200, the panel is in the open position and when the air flow ceases, gravity pulls the panel back to the closed position. Preferably, each damper 260 operates independently so that if a portion of the fan unit 200 is activated and a portion of the fan unit is deactivated, the dampers 260 can be opened or closed accordingly. Although shown as a simple mechanical embodiment, alternative embodiments may include electronic control and/or remote control of the structure from the damper.

It should be noted that fig. 4 shows a 4 × 6 fan array fan section in an air-handling system having twenty-four fan units 200, fig. 5 shows a 5 × 5 fan array fan section in an air-handling system having twenty-five fan units 200, fig. 6 shows a 3 × 4 fan array fan section in an air-handling system having twelve fan units 200, fig. 7 shows a 3 × 3 fan array fan section in an air-handling system having nine fan units 200, and fig. 8 shows a 3 × 1 fan array fan section in an air-handling system having three fan units 200. It should be noted that while the fan units 200 may be arranged in a single plane (as shown in fig. 3), alternative array configurations may include a plurality of fan units 200 arranged in a staggered configuration in multiple planes (as shown in fig. 15). It should be noted that cooling coils (not shown) may be added to the system either upstream or downstream of the fan unit 200. It should be noted that although the filter banks 122, 222 are shown upstream of the fan unit 200, the filter banks 122, 222 may be downstream.

It should be noted that alternative embodiments use a horizontally arranged array of fans. In other words, the embodiments shown in fig. 3-15 may be used horizontally or vertically or in any direction perpendicular to the direction of airflow. For example, if a vertical portion of the air duct is used as the air-conditioning room 202, the fan array may be arranged horizontally. This embodiment is particularly useful in an air-conditioning room for a return air shaft.

It should be noted that the fan section 214 may be any portion of the airway path 220 in which the fan unit 200 is disposed. For example, the fan unit 200 may be disposed in the exit plenum 212 (as shown), in the intake plenum 212, or partially within the intake plenum 212 and partially within the exit plenum 210. It should also be noted that the air-conditioning compartment 202 may be part of an air duct.

It should be noted that many features and characteristics associated with fan unit compartment 244 (fig. 17) will be the same as or similar to the characteristics of fan unit compartment 244' (fig. 18-23).

The terms and expressions which have been employed in the foregoing specification are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding equivalents of the features shown and described or portions thereof. The scope of the invention is only limited and limited by the appended claims.

Claims (20)

1. A fan array fan section in an air-handling system, comprising:

(a) at least three fan units;

(b) each of the at least three fan units is located within a fan unit chamber/cell;

(c) each fan unit chamber/cell having at least one insulation surface;

(d) the at least three fan units are arranged in a fan array; and

(e) an air-handling compartment within which the fan array of the fan unit is located.

2. The fan array fan section in an air-handling system of claim 1, wherein the isolated surfaces of said fan unit chambers/cells together form a coplanar silencer.

3. The fan array fan section in an air-handling system of claim 1, wherein each fan unit chamber/cell is a cell having a frame supporting the insulation surface.

4. The fan array fan section in an air-handling system of claim 1, wherein each of said insulation surfaces is made of an acoustically dampening material.

5. The fan array fan section in an air-handling system of claim 1, wherein sound waves from said fan units that pass through said insulation surface are at least partially dissipated as they pass through said insulation surface.

6. The fan array fan section in an air-handling system of claim 1, wherein each of said at least three fan units is suspended within a fan unit compartment such that there is an air discharge passage beneath each of said at least three fan units.

7. The fan array fan section in an air-handling system of claim 1, wherein said at least three fan units are a plurality of fan units arranged in a fan array configuration selected from the group consisting of:

(a) a solid array configuration;

(b) a spaced apart pattern array configuration;

(c) constructing a checkerboard array;

(d) an array configuration with slightly offset rows;

(e) array configurations with slightly offset columns; and

(f) a staggered array configuration.

8. The fan array fan section in an air-handling system of claim 1, wherein said at least three fan units are blower fans comprising at least two vertically aligned fan units.

9. The fan array fan section in an air-handling system of claim 1, wherein each of said at least three fan units is mounted within a grid system.

10. The fan array fan section in an air-handling system of claim 1, wherein said fan unit compartment/cabinet is a modular unit for use within a modular unit system.

11. A fan array section in an air-handling compartment that is part of an air-handling system for air-handling a structure, the fan array section comprising:

(a) a plurality of fan units;

(b) the plurality of fan units are arranged in a fan array;

(c) each of the plurality of fan units is located within a fan unit chamber/cell;

(d) each fan unit chamber/cell having at least one sound absorbing insulation surface; and is

(e) The separate surfaces of the fan unit chambers/cells together form a coplanar silencer.

12. The fan array section of claim 11, wherein each of the fan unit chambers/cells is a cell having a frame supporting the insulation surface.

13. The fan array section of claim 11, wherein sound waves from the fan units that pass through the insulation surface are at least partially dissipated as they pass through the insulation surface.

14. The fan array fan section of claim 11, wherein each of the plurality of fan units is suspended within a fan unit chamber/cell such that there is an air release passage beneath each of the plurality of fan units.

15. The fan array fan section of claim 1, wherein the plurality of fan units are a plurality of fan units arranged in a fan array configuration selected from the group consisting of:

(a) a solid array configuration;

(b) a spaced apart pattern array configuration;

(c) constructing a checkerboard array;

(d) an array configuration with slightly offset rows;

(e) array configurations with slightly offset columns; and

(f) a staggered array configuration.

16. A fan array section in an air-handling compartment that is part of an air-handling system for air-handling a structure, the fan array section comprising:

(a) a plurality of fan units;

(b) the plurality of fan units are arranged in a fan array;

(c) each of the plurality of fan units is located within a fan unit cell;

(d) each fan unit cell having a frame; and is

(e) Each fan unit has at least one sound absorbing insulation surface formed on at least one side of the fan unit cells, the at least one insulation surface being supported by the frame.

17. The fan array section in an air-handling system of claim 16, wherein the isolated surfaces of the fan unit cells together form a coplanar silencer.

18. The fan array section in an air-handling system of claim 16, wherein each of said insulation surfaces is made of a sound absorbing material.

19. The fan array fan section in an air-handling system of claim 11, wherein sound waves from said fan units that pass through said insulation surface are at least partially dissipated as they pass through said insulation surface.

20. The fan array fan section in an air-handling system of claim 1, wherein said plurality of fan units are a plurality of fan units arranged in a fan array configuration selected from the group consisting of:

(a) a solid array configuration;

(b) a spaced apart pattern array configuration;

(c) constructing a checkerboard array;

(d) an array configuration with slightly offset rows;

(e) array configurations with slightly offset columns; and

(f) a staggered array configuration.