Patent Grant
10527046
The present invention relates generally to the design of a heating, ventilating and air conditioning unit used in conjunction with high volume, low-speed fans. More particularly, the present invention pertains to the design of an apparatus to deliver chilled or heated air through stepped louvres of a manifold to the blades of a fan in which the leading edge has regular steps at a predetermined ratio configured to create turbulent airflow.
The indoor environment is a significant concern in designing and building various structures. Human and occupant comfort are largely affected by airflow, thermal comfort and relevant temperature. Airflow is generally the measurable movement of air across a surface. Relevant temperature is the degree of thermal discomfort measured by airflow and temperature. Airflow that improves an employee health and productivity can have a large return on investment. High volume, low-speed ceiling and vertical fans can provide significant energy savings and improve occupant comfort in large commercial, industrial, agricultural and institutional structures. High volume low-speed (HVLS) fans are the newest ventilation option available today. These large fans, which range in size from 8 to 24 feet, provide energy-efficient air movement throughout a large volume building at a fraction of the energy cost of high-speed fans.
The main advantage of an HVLS fan is its limited energy consumption. One 20-foot fan typically moves approximately 125,000 cubic feet per minute (cfm) of air. It takes six to seven standard fans to provide similar volume of air movement. An eight-foot fan can move approximately 42,000 cfm of air. Most HVLS fans employ a 1 to 2 HP motor, moving the same volume of air (for approximately one-third of the energy cost) of six high-speed fans.
HVLS fans move large columns of air at a slow velocity, about 3 mph (260 fpm). Air movement of as little as 2 mph (180 fpm) has been shown to provide a cooling effect on the human body according to the Manual of Naval Preventive Medicine. In fact, airflow at 2 mph will give a cooling effect of approximately 5° F. (the air feels 5° F. cooler) and an airflow of 4 mph will provide a cooling effect of approximately 10° F.; that is, if the actual temperature was 75° F. with an airflow of 4 mph, the relative temperature would be 65°. The cooling effect is described as the relative temperature. Moreover, it has been shown that turbulent airflow provides a more-effective cooling sensation than uniform airflow by David W. Kammel, et al., “Design of High Volume Low Speed Fan Supplemental Cooling System in Free Stall Barns.”
A study done by the University of Wisconsin shows that HVLS systems provide more widespread air movement throughout the building or space to be cooled. One disadvantage of traditional HVLS fans is that they have an area of “dead” air (air that has minimal air movement) in close proximity to the centerline of the fan.
Although high-speed fans provide more velocity, each unit impacts only a small, focused area. High-speed fans are good for managing extreme heat, although they can cause a dramatic increase in energy consumption in the hot, summer months. High-speed fans produce higher velocities in the area directly surrounding each fan, leaving large areas of dead air outside the diameter of the fan blades.
HVLS systems are sometimes used year-round. In summer, HVLS fans provide essential cooling; in winter, the fans move warmer air from ceiling to floor level and may result in a more comfortable environment. HVLS fans are virtually noiseless. HVLS fans provide more comfort to individuals positioned in proximity to the fan, because the airflow causes a lower relevant temperature—that is, the air temperature feels cooler because of the movement of the air. The optimal airflow velocity for HVLS fans is typically between 2 to 4 miles per hour for most operations. Spacing the fans too far apart will significantly diminish the system's benefits.
HVLS fans cost approximately $4,200-$5,000 each, including installation. While this is a large upfront investment, facility must use six to seven high-speed fans at $200-$300 each to move the same volume of air as with one HVLS fan. Energy savings realized through the use of HVLS fans over a high-speed fan system should make up the cost difference within two to three years. Manufacturers claim that HVLS fans typically do not require replacement for at least 10 years. Because high-speed fans operate a higher RPM, the motors typically need to be replaced more frequently than with HVLS fans.
The components of a typical fan include:
There are axial flow fan blades available in the prior art that address the issue of increasing the efficiency of a fan. For example, U.S. Pat. Nos. 4,089,618, 5,603,607 and 5,275,535 all pertain to fan blades in which the trailing edges contain notches or a saw-tooth shape. Additionally, in U.S. Pat. No. 5,275,535, both the leading and the trailing edges are notched. Moreover, U.S. Pat. Nos. 5,326,225 and 5,624,234 disclose fan blade platform shapes that are curved forward and backward. Despite the fact that the referred patents may present a reduction on the noise level and an increase on the efficiency, the improvement obtained is quite modest. Consequently, the applicability of these patents is limited in actual practice. Another prior art technology, as depicted in U.S. Pat. No. 8,535,008, utilizes a leading edge which includes a series of spaced “tubercles” formed along the leading edge of the rotor blade.
None of the prior art shows a stepped-louvre configuration in an air handling manifold or diffuser nor do the patents depict a stepped-fan blade. There is a need for a stepped-louvre configuration in an air handling manifold to create turbulent airflow and deliver an increased velocity over a greater volume. The stepped-louvre configuration in an air handling manifold may be used in connection with a high volume, low-speed fan having a stepped blade configuration to create turbulent airflow and deliver an increased volume of either cooled or heated air to create a more comfortable environment.
It has been determined that turbulent airflow is more effective at providing a cooling sensation than uniform airflow. The present invention incorporates a stepped design on the leading edge of the fan blade. The leading edge of the fan blade is stepped such that the widest portion of the blade is located closest to the hub of the fan. The leading edge is stepped down from the hub at predetermined intervals such that the width of the overall fan blade decreases at each step. The present invention includes a leading edge which extends beyond the generally uniform width of a typical fan blade. The steps may be of equal length whereby the first step closest to the hub is the same length as the other steps. Thus, a preferred ratio of the width of the steps of the leading edge in the present invention is approximately 3:2:1. By way of example, the leading edge may be an additional three inches from the width of the body portion in a typical fan blade, the second step is an additional two inches from the width of the body portion of a typical fan blade and the third step is an additional one inch from the width of the body portion of a typical fan blade. The steps provide for increased turbulent airflow. While the steps may be of any proportion, it appears that steps of uniform proportion create the optimal turbulent airflow.
One of the benefits of having a stepped leading edge on the fan blade is that movement of the blade creates greater airflow velocity than the existing fan blade.
Another advantage of the stepped design is that it provides for a more balance airflow and greater coverage area.
Yet another advantage of the present invention is a greater velocity of airflow in the “dead area” below the centerline of the fan. In a typical fan blade design, the area directly under the hub of the fan to a distance of approximately twenty feet from the hub does not receive a significant amount of airflow. This area was known as the “dead area.” The stepped configuration of the leading edge of the present invention provides for airflow within the dead spot; that is the fan blade of the present invention has a dead spot of less than three feet.
Additionally, the design of the present invention provides the benefit of extending the effective range of air movement an additional 8-9 feet beyond the range of a fan having standard saw blades. Advantage that with a stepped leading edge, the angle of the blade can be up to 22° whereas typical HVLS fans are between 10° to 15°.
Another invention includes a manifold or diffuser to deliver air to a desired location. The manifold has an inlet and outlet whereby the outlet has one or more louvres. The louvres are adjustable to control the volume of air that is discharged from the manifold. The louvres include a stepped design along one edge of the louvre. The stepped-louvre design provides a more balanced airflow.
Another advantage of the stepped louvre is that it creates greater airflow velocity than existing louvres.
The manifold and stepped-louvre design may be utilized with a conventional fan or may be used with the stepped-fan blade design of the present invention. The benefits of using the manifold having stepped louvres in connection with the stepped-fan blade design are that the stepped louvres may be combined with the stepped-fan blade design to distribute either heated air or chilled air in a turbulent fashion and provide for a more balanced distribution of the air. The benefits of the fan described above will also apply to the air handling manifold having stepped louvres.
Other benefits of the manifold of the present invention may be found in the generally trapezoidal shape of the manifold. The trapezoidal shape provides for improved distribution of air along the top portion of the fan blades such that the cool air from the manifold or diffuser is more evenly distributed by the fan blade. If air is distributed at only one point at the top of the fan blade, as in prior art designs, the fan tends to push the cooled air into one specific area, rather than uniformly distributed the air. The trapezoidal shape manifold or diffuser distributes the air more evenly along the fan blade to permit a relatively even distribution of the air by the fan, rather than having the cooled air pool in one specific area.
The invention further includes an embodiment which has openings in the bottom portion of the manifold positioned above the dead zone of the fan. The openings permit cooled air from the manifold or diffuser to be distributed directly into the dead zone of the fan.
Finally, one of the embodiments of the present invention includes a unique system for controlling the configuration of the louvres such that optimal air flow from the manifold or diffuser may be directed along the top surface of the fan blade.
While some of the advantages of the present invention are set forth above, the full extent of the benefits of the present inventions will be understood in the drawings and detailed description of the preferred embodiments of the invention set forth below.
Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the following drawings:
A typical high volume, low-speed fan has between four to eight fan blades. The fan blades are typically between 4-feet to 12-feet in length and have a width of 6 inches. Thus, the total diameter of a typical fan is between 8-feet (96 inches) to 24-feet (288 inches).
In the preferred embodiment of the present invention, as shown in
The preferred embodiment shown in
The stepped configuration of the leading edge 32 of the fan blade is shown in more detail in
The steps 40, 42 and 44 preferably have generally equal lengths proportional to the length of the blade body 38. Thus, the first step 40 would be approximately ⅓ the total length 39 of the blade body 38. The second step would also be approximately ⅓ the total length 39 of the blade body 38. Likewise, the third step would be approximately ⅓ the total length 39 of the blade body 38. The steps 40, 42 and 44 have a width in a ratio of 3:2:1. Thus, the distance that the first step 40 extends beyond the front edge of the blade body 38 is 3-inches; the distance the second step 42 extends 52 is 2-inches and the third step 44 extends 54 is 1-inch. The ratio of the distance the various steps 40, 42 and 44 extend beyond the front edge of the blade body 38 is 3:2:1. While the preferred embodiment has steps of proportional length and proportional width, it is not a requirement. The important aspect of the step configuration is that the leading edge has multiple steps, from the area of the fan blade 30 closest to the hub. The steps decrease the thickness of the blade in each step that proceeds from the hub.
While the preferred number of steps is three with a ratio of 3:2:1, the number of steps may be more than three, so long as the ratio of length of the steps corresponds to the number of steps and the distances the various steps extend beyond the front edge of the blade body is a ratio equal to the number of steps.
The pitch P of the blade 30 is approximately 22°. The design of the steps 40, 42 and 44 along the leading edge 32 of the blade 30 permits for the blade to accommodate up to a 22° pitch. Conventional HVLS fans typically have a pitch for the blade between 10°-15°. The stepped design of the leading edge of the fan blade allows for a pitch between 18° to 22° to be implemented without increasing the strain of the motor. The increased pitch promotes more downward airflow.
The steps 40, 42 and 44 along the leading edge 32 of the fan blade 30 have edges 60 and 62 respectively. The edges 60 and 62 of the preferred embodiment have a recessed or Z-shaped configuration. This configuration is for aesthetic purposes. As shown in
An actual embodiment of the preferred invention was tested at a warehouse facility in Beaver Dam, Wisconsin. The height of the facility was twenty-five feet from the floor to the ceiling. The high-velocity, low speed fan was a 24-foot diameter fan that was mounted twenty feet from the floor—in other words, the fan had approximately a five foot drop from the ceiling. The fan had five blades including three steps on each blade as depicted in
This chart shows that the stepped design has significant airflow coverage and overall air dispersion. The fan of the current invention has minimal airflow dead spots, especially within close proximity to the centerline of the fan.
The air-flow manifold utilizing a stepped-louvre design may be seen in
In
The stepped-louvre, air flow manifold 300 typically has a trapezoid shaped diffuser 360 such that air is delivered from the HVAC duct 350 and is equally dispersed through one of the two openings 380 of the diffuser 360. While it is preferred that the diffuser 360 is trapezoid shaped,
The openings 380 of the diffuser 360 are preferably rectangular in shape, but may be of any desired shape. The opening 380 includes a bracket 382, to which the louvres 400 are rotatably affixed 408. The louvres 400 have a stepped configuration, including a first step 402, a second step 404 and a third step 406 in the preferred embodiment of the first step 402 is the thickest, relative to the second step 404 and the third step 406.
The stepped configuration of the stepped louvre 400 is shown in more detail in
The steps 402, 404 and 406 preferably have generally equal lengths proportional to the length of the louvre 400. Thus, the first step 402 would be approximately 1/3 the total length of the louvre 400. The second step would also be approximately 1/3 the total length of the louvre 400. Likewise, the third step would be approximately 1/3 the total length of the louvre 400. The steps 402, 404 and 406 have a width in a ratio of 3:2:1. Thus, the distance that the first step 402 extends beyond the front edge of the louvre 400 is 3-inches; the distance the second step 404 extends 2 inches and the third step 406 extends 1 inch. The ratio of the distance the various steps 402, 404 and 406 extend beyond the front edge of the louvre body 400 is 3:2:1. While the preferred embodiment has steps of proportional length and proportional width; it is not a requirement. The important aspect of the step configuration is that the edge has multiple steps, from the area of the louvre 400. The steps decrease in thickness of the louvre in each step.
While the preferred number of steps is three with a ratio of 3:2:1, the number of steps may be more than three, so long as the ratio of length of the steps corresponds to the number of steps and the distances the various steps extend beyond the front edge of the blade body is a ratio equal to the number of steps.
As shown in more detail in
A positioning member 460 includes a fine adjustment mechanism 465 that transmits a fine adjustment mechanism 465 that transmits a fine adjustment from the guide element 420, such that the first bushing 430 and second bushing 432 may be adjusted up or down to make a relatively small adjustment of the angle of the louvre 400. The preferred embodiment of the fine adjustment mechanism 465 may be a threaded member and a first nut 467 and second 468 nut positioned on the threaded member of the fine adjustment mechanism 465. The threaded member engages a slot 469 or hole in the positioning member 460. The first nut 467 and second nut 468 are positioned on either side of the slot 469 of the positioning member 460. Rotation of the first nut 467 and second nut 468 impart movement of the positioning member 460 which, in turn, imparts movement of the guide element 420 to the desired louvre position 400. Once in place, the louvre 400 may be locked in place by locking the positioning member 460.
Air exits the opening 380 of the diffuser 360 and is directed by the louvres 400. The louvres 400 may be adjustable to direct the airflow from the opening 380 along the fan blades 330. The louvres 400 further create a turbulent airflow over the fan blades 330 which causes a greater dispersion of the air. Based upon applicant's understanding of the design, it is estimated that the airflow can be detected up to 75 feet from the center line of the fan 10.
The fundamental operating principals and indeed many of the engineering criteria of fan blades for high volume low-speed ceiling fans is similar to fan blades used in basically all forms of compressors, fans and turbine generators. In other words, the rotor blades can be used in a huge range of products such as for example, for helicopter blades, car fans, air conditioning units, water turbines, thermal and nuclear steam turbines, rotary fans, rotary and turbine pumps, and other similar applications.
Although embodiments of the present invention have been described, those of skill in the art will appreciate that variations and modifications may be made without departing from the spirit and scope thereof as defined by the appended claims.
This application is a Continuation-In-Part of U.S. application Ser. No. 15/043,923 filed Feb. 15, 2016 which is a Continuation-In-Part of U.S. application Ser. No. 14/814,161, filed Jul. 30, 2015; the '923 and the '161 applications are now pending and incorporated by reference herein.
| Number | Name | Date | Kind |
|---|---|---|---|
| 6458028 | Snyder | Oct 2002 | B2 |
| 20070154315 | Bucher | Jul 2007 | A1 |
| Number | Date | Country |
|---|---|---|
| 2006009699 | Jan 2006 | JP |
| WO-9844299 | Oct 1998 | WO |
| WO2014026246 | Feb 2014 | WO |
| Entry |
|---|
| WO 9844299 Specification English Translation, Espacenet (Year: 1998). |
| All Out Cool, Outdoor Fan: Blades, Refereed to as “AOC” in office action, Dated Feb. 12, 2011 (Year: 2011). |
| European Search Report and Written Opinion dated Dec. 5, 2016. |
| Number | Date | Country | |
|---|---|---|---|
| 20170114789 A1 | Apr 2017 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 15043923 | Feb 2016 | US |
| Child | 15346913 | US | |
| Parent | 14814161 | Jul 2015 | US |
| Child | 15043923 | US |
