Air Handler Design for Modular Manufacturing of High Performance and No Shutdown Units
This patent application covers design and modular manufacturing techniques for an economical air handler and exhaust fan product line that delivers better energy performance, acoustical performance, space utilization, and operational efficiency than is available in today's marketplace. An axial fan is positioned within airflow guides designed to minimize turbulence to reduce acoustics and energy consumption. The specific arrangement of air filters, heating and cooling coils, airflow guides, sound attenuating surfaces, fan modules, control panels, backdraft dampers and isolation dampers enables the stacking of modular units to meet air handler capacity requirements with inherent redundancy. In some configurations, the air handler described provides complete redundancy for a no-shutdown system that will reduce HVAC energy requirements to a lower level and provide a greater operating range than is available in today's market.
Air handlers combine fans with thermally active components to deliver specific quantities and qualities of air. The air handler industry has evolved to offer products predominantly using centrifugal fans because they are easier to configure and assemble in diverse HVAC application. However, axial fans have the potential to provide better performance and efficiency if designed and configured properly. Axial fans are uncommon in air handler manufacturing due to the complex aerodynamic challenges that often result in excessive noise and the potential for extreme turbulence that reduces fan performance efficiency. In the past, some air handler manufacturers offered axial fan air handlers that operated much more efficiently than mass produced air handlers. However these products are not available in today's market because of the high cost of custom manufacturing, and the difficulties of engineering an efficiently designed axial fan system. With increasing awareness of energy and environmental issues, a highly efficient and cost effective axial fan air handler product is needed by the marketplace. This patent covers the design and product line marketing strategies for a modular line of axial fan air handling products with interchangeable components to address a wide variety of applications with more energy efficiency, quieter operation, and a greater operating range than other options available in today's marketplace.
SUMMARYThis patent covers an air handler and fan modular manufacturing system to provide unique energy efficiency and operational improvements at an economical cost. A specific feature of this air handler series design (AxHU) is the use of axial fans in a modular approach (Axial Fan Modules) that can be combined together in a stack, line or grid or array arrangement and combined with flow straighteners, acoustic attenuating surfaces, return air pathways, control panels, sensors, instruments, air filters and heat exchange coils to comprise an air handler. The specific arrangement of components described here provides a low profile air handler that can be stacked to provide the capacity needed for each application. This results in an air handler (AxHU) made up of multiple sections (Blades) that together can provide complete redundancy in case of any single component failure for an air handler that will never need to shut down, which is very valuable for critical facilities such as hospitals, labs, cleanrooms and datacenters. A version of the AxHU uses VFDs, software controlled, or ECM motors with axial and/or centrifugal fans to serve in certain configurations where they are most appropriate. Manufacturing cost savings come from using mass produced instead of custom-built components by producing only a few sizes of fan modules and combining them to meet the specific required capacities. The AxHU overcomes the aerodynamic challenges of axial fan operation in a fan module that can be arranged in an array or grid to support an economical modular manufacturing operation. Also, the fan modules can be used in an exhaust, return, in-line or plenum fan application for economic manufacturing operation. The intake and discharge sections can be modified to meet the desired capacity for each application. This AxHU system is unique because the specific arrangement of components allows for a lower overall pressure drop and efficiency level without large increases in equipment capital costs, and comprises an air handling system with complete redundancy. The modular design also allows the sequential staging of each Blade to produce a much wider airflow operating range to address challenges where extremely low airflow levels are needed. Together these design features comprise an fan system with lower capital costs, equipment footprints, acoustical levels, power requirements, and service costs while providing improved reliability, redundancy, and operating range. These benefits are only achieved through the axial fan modular designs and specific configurations described in this patent.
Blade: The combination of the air filters, coils, head, end sections, Axial Fan Modules, piping, and controls comprises a Blade in different standardized sizes to be combined to form an air handler comprised of a Blade stack or row. Together, the sizes of the Blades will be combined to accommodate any system capacity desired while supporting economical modularized manufacturing with repeatedly used components. As the AxHU ramps through its designed discharge range to meet the system demand, the axial fan assemblies are staged on and off to maintain the most efficient operation the overall fan system while avoiding a stall condition from any single fan using the automatic isolation dampers to stage the fans properly. The isolation dampers, automatic, backdraft or manual, will isolate and enable the replacement of a single fan while the entire AxHU remains in operation without interruption of service. For critical facility units, an entirely cleanable wash-down AxHU version enables the servicing of all components without a loss or disruption of operational service. The layout of the blade design follows the Constructal Law parameters to make equal time spent for the air to traverse each segment of the blade with an overall design focus of minimizing energy losses. As another alternative design, the acceleration may be completely handled by the Head section with little airflow acceleration done by the airflow guides on the inlet to the Axial Fan Module.
AxHU: Various amounts of equal sized blades are combined to meet specific capacity and redundancy requirements to form an AxHU. An airflow straightener transition section is included on either side of the fan array as needed to meet the application requirements with a minimum of turbulence. The airflow accelerator and deceleration sections utilize a Constructal Law guided design for the minimization of turbulence, boundary layer separation and best energy performance. The development and further refinement of the acceleration and deceleration section designs will be guided by aerodynamic analysis and empirical testing. A version of the accelerator section uses airflow separators in line with the air movement that gradually expand each section symmetrically in a gradual flare. The Axial Fan Modules transition into a head section that turns the airflow without turbulence to create a compact air handler unit. The most common configuration of the head section is a 90 to 180 degree redirection of the airflow incorporating an airflow acceleration, acoustical dampening, and flow straightening function. This head section reroutes and accelerates the air, dampens acoustical energy, and can be configured with an optional access door for maintenance purposes. The head section transitions the air from the filter and coil section, which can be on one, two, three, four or five sides of the air handler. This correlates to the use of a head section that is one, two, three or four sided, however the single and double sided head sections are the most commonly used for economical mass production. The head section can be made with single or multiple layers of perorated metal or plastic guides incorporating an optional plastic, kynar, nylon, mylar, fiberglas, mineral wool, or other similar material liner designed to absorb acoustical energy. The airflow guides in the head section are fabricated in simple geometric shapes including circles and elongated circles for ease of manufacturing with guides, supports and spacers that can be mass-produced and used for all sizes of air handlers and fans. Other optional head sections have specially shaped airflow guides designed to optimize energy performance and minimize space requirements using parabolic or other shapes tailored for custom applications. An option is to use rounded guides that decrease the angle of air curvature in proportion to the inertia or momentum of the accelerating or decelerating air flow.
The filter/coil section is designed to distribute the air evenly, minimize pressure drop and turbulence, and provide easy access for maintenance purposes. All corners and transition sections of the AxHU have smooth, rounded corners to minimize turbulence generation. The cooling and heating coils are placed back to back with the header piping located in a downstream location over the drain pan, which can be made of stainless steel or with anti-microbial materials as an option (either silver impregnated stainless steel, copper, plastic, or a specially coated metal surface). As an option, the entire interior of the AxHU can be made of anti-microbial materials, and with optional UV lighting. The length of the AxHU will be determined by the desired pressure drop from the air filters and coils, and the airflow pathways will be designed to minimize turbulence and pressure drops with smooth surfaces and transitions between sections. Other options are a unit made entirely of non-ferrous materials.
Opposite the head section is the end, usually the discharge end and the return air intake. The return air intake can enter the AxHU from the end, side or top, and an access door can be installed in the end for many configurations. The discharge end of each axial fan assembly has airflow expanders that decelerate the air without causing turbulence or significant boundary layer separation. Additionally, there will be a final flow straightening section at the discharge end of the axial fan assemblies consisting of straight vanes or grids, rectangular mesh or hexagonal structures to minimize the possibility of system effects resulting from improper field installations. For the Operationally Efficient Package, provisions for the complete isolation of each blade's filter and coil section enables the changing of filters without impacting the controlled environments being served. In the end section, a specialized shut-off panel system engages to maintain stable operations when a single fan needs to be shut down and isolated. This results in an affordable fully redundant air handler system that never needs shutdowns for its entire service life.
The floor of the air handler will range from an inexpensive sheet metal surface to a cleanable, stainless steel basin with an interior designed for wash down applications for clean facilities. The access doors and closure panels will be sealed tightly to minimize air leakage. The AxHU enclosure will be sealed tight with a thermal break construction for outdoor applications. High performance double and triple gasketed doors available for critical facilities. Each section will come with optional sealed drains and sealed conduit penetration for future upgrades needed.
As an alternate to the head section design, a sheetmetal coil wound in a spiral would create the accelerating airflow needed for the axial fan inlet in an intake plenum. This may be a segmented spiral made of 3, 5, 7, or 11, or other prime number of straight airflow guides that produces a doubling of surface area while preventing significant air boundary layer separation. This air accelerator coil will have rigid supports spanning the intake and discharge ends to stabilize the airflow guides. These supports will have a slant built into them to pre-rotate the air stream in the direction of fan rotation at an angle determined to optimize fan performance. This and many other features are designed to improve the overall fan assembly performance resulting in ‘negative system effects’, which is fan performance that exceeds AMCA test results.
The AxHU can be made in a 100% outside air supply fan configuration, or with a return or relief fan section for commercial applications. The return ductwork connects to a section outside of the air filters next to the fresh air inlet section. Dampers control the amount of outside air versus return air for a modulating economizer function. An optional configuration has the air filters and thermal coils mounted at an angle in the vertical plane to accommodate a return air connection into a mixed air section. Also, the mixed air section can be configured with a humidifier for tightly controlled environments. The economizer components are made with corrosion resistant materials and sealed from the environment. Another version of the AxHU is configured with a final filter section including HEPA and ULPA filters. In this arrangement, the deceleration section is followed by another head section that slows down the air gradually and routes it into an oversized discharge section upstream of the final filters to support energy efficient operation. For applications that have space constraints, the return fan can be located in the ductwork independently of the AxHU.
The Axial Fan Module or Modules can be configured as an exhaust or transfer fan product with an exhaust plenum accelerator option. Many Axial Fan Modules can be combined as a fan manifold that stage on and off to maintain desired service with a minimum of energy consumption. Options include a controllable air bypass damper and anemometer based speed control.
Sensors and instruments are included since they are important to ensuring the proper functioning and maintenance of the HVAC system operations. AxHUs are tailored for different markets requiring specialized automation options. Three levels of AxHU instrumentation are offered in the basic, the energy efficient, and the operationally efficient packages.
The Basic Instrumentation Package includes manual air filter differential pressure gauges, fan failure alarms, and fan motor drive interface to BAS. The Operationally Efficient Package adds remote monitoring for air filter differential pressure, vibration monitoring, airflow monitor, current sensors and outdoor airflow monitor. Along with other specialized AxHU features, the Operationally Efficient Package delivers continuous uninterrupted HVAC service without disruptions for maintenance operations, which is important for critical facilities. The Energy Efficient Package includes added temperature differential across coils (air and water side), differential pressure across the fan assemblies, airflow monitor, motor amperage power readings, alarm records, and a differential pressure across the entire AxHU.
The AxHU line will be designed for three different general applications:
1. Office=Atlas
2. Laboratory=Stratus
3. Cleanroom=Polaris
Each line will have standard features and special upgrades and options tailored to their market. The Atlas will have a tightly sealed cabinet with options for spare conduit penetrations. Stratus will have strengthened cabinet with a checkerplate flooring turned up at the edges to hold standing water. There will be an optional floor drain in each section with a tightly sealed screwed cap daylighting to the exterior of the AxHU base. The Polaris will be specialized for cleanroom and healthcare applications with cleanable, no gap interior, continuous no-shutdown design, and deluxe automation package.
Claims
1. Modular air handler manufacturing line using axial or centrifugal fan standardized componentry combined to meet required applications with specializations for different markets. The most common AxHU layout (horizontal Blade) consists of a low cost modular fan assembly with a low pressure drop filter and coil section and an easily accessible control panel that allows for the rapid removal and isolation of an individual fan and motor. Additionally, an alternate configuration involving a 90-degree re-orientation of the control panels, filters and coils enables the Blade to be mounted in a vertical instead of horizontal position.
- a. Modular AHU and Fan system using axial fan modules designed for minimum turbulence and acoustics.
- b. Different fans can be provided for different system capacity requirements without changing other parts of the AxHU. The fans will be assembled in modules that can be included with different filter, coil, and airflow guide configurations for different applications.
- c. Main component is the Axial Fan Module, which includes the fan, housing, isolation dampers, nosecones, airflow guides, sound attenuators, backdraft dampers, and power and control panel.
- d. The nosecones on the intake and the discharge side of the fans may be similar or different design from each other to minimize energy consumption. The nosecones will be a conical or square-to-round shape to match the intake and discharge duct square-to-round sections. The nosecone surfaces and surrounding duct sections may have acoustically absorbing surface finish or perforations. An intermediate concentric cylindrical airflow guide will be used surrounding the nosecones to improve airflow stability in some configurations. This cylindrical airflow guide may be eliminated for the fan intake section to take advantage of the cost benefits of using a modular product line approach.
- e. The Axial Fan Module can be used as a supply, return, exhaust, in-line, or plenum fan in a stand-alone or in combination with others in a row, stack, in-series, or grid configurations. They can be provided with multiple Axial Fan Modules in series with intermediate nosecones for higher pressure applications.
- f. The Axial Fan Module combined with other airflow control and thermally active components, controls and sensors comprises a Blade, which can be stacked vertically or horizontally to meet the required Air Handler (AxHU) capacity.
- g. The discharge decelerator sections are available in different interconnecting options for different applications, such as in-line, shaft discharge, or plenum, and for different discharge airflow requirements.
- h. The air intake section for each Blade uses a row or rows of air filters designed for low velocity airflow, followed by optional preheating, cooling and optional reheating coils, UV lights and other optional systems as needed for each application.
- i. Each fan module control panels will be mounted on the outside of the AxHU in some configurations to enable the stacking of each independent Blade section.
- j. Refrigeration section may be included in the AxHU attached to the End Section.
2-14. (canceled)
Type: Application
Filed: Aug 3, 2020
Publication Date: Feb 3, 2022
Inventor: Gary Peter Shamshoian (Cupertino, CA)
Application Number: 16/984,147