Patent Publication Number: US-2017356664-A1

Title: Hvac delivery system in high volume low-speed fan

Description:
This application claims priority from Provisional Patent Application Ser. No. 62/332,191 filed May 5, 2016. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to the design of a heating, ventilating and air conditioning (“HVAC”) 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 an HVAC delivery system positioned to direct air through (or in close proximity to) the centerline of the fan to a position wherein the fan blades influence the chilled or heated air. The HVAC delivery system may be used in conjunction with conventional ceiling fans or ceiling fans utilizing the Z-Tech™ stepped leading edge design. 
     BACKGROUND OF THE INVENTION 
     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 defined as the measurable movement of air across a surface. Relative temperature is typically defined as the degree of thermal discomfort measured by airflow, temperature and humidity. Airflow that improves an employee health and productivity has been proven to have a significant benefit on the attitude of employees. 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&#39;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:
         An electromagnetic motor;   Blades also known as paddles or wings (usually made from wood, plywood, iron, aluminum or plastic);   Metal arms, called blade mounts (alternately blade brackets, blade arms, blade holders, or flanges), which hold the blades and connect them to the motor;   A mechanism for mounting the fan to the ceiling.       

     While HVLS fans are utilized in commercial settings, in the residential environment, the HVLS fan is generally called a “ceiling fan.” Typically, the ceiling fan has smaller dimensions than the HLVS fan, but operate in a similar fashion. The ceiling fan rotates at a much slower speed than a high-speed fan. The ceiling fan introduces slow movement to otherwise still air, inducing evaporative cooling effect upon a human positioned within range of the ceiling fan. A ceiling fan does not actually cool the temperature of the air, rather the ceiling fan increases airflow to create a lower relative temperature—the temperature one feels impacted by the movement of air across the skin&#39;s surface. The rotation of the fan blade forces the air downward to create a wind-chill effect upon any human standing in the vicinity of the fan, as shown in  FIG. 8 . 
     A ceiling fan is different from an air conditioning unit in that the air conditioning equipment reduces the actual temperature of the air in the room, while the ceiling fan reduces the relative temperature experienced by a personal to the movement of the air. 
     In the winter months, a ceiling fan may be used to reduce the stratification of warm air in a room—that is the air close to the ceiling may be as much as 10° F. to 15° F. warmer than air near the floor—by forcing the warmer air down toward the floor near the exterior walls of the room where windows and doors are located to more evenly distribute the warm air without causing direct airflow on a person located under the fan, as shown in  FIG. 9 . 
     There exists a need for a HVLS fan or ceiling fan to operate in combination with an HVAC system. More importantly, there is a need for the HVAC system to be a integral part of the HVLS fan or ceiling fan such that the air distributed from the HVAC system operates to converge with the air-flow created by the fan blades. 
     SUMMARY OF THE INVENTION 
     One of the aspects provided by the current invention is to have a HVAC system as an integral part of the fan to provide air flow from the HVAC system to the blades of the fan. The HVAC system is positioned in such a manner as to direct the heated or cooled air into the stream of air created by the movement of the fan blades of the fan. The preferred method of delivering the heated or cooled air of the HVAC system is to direct the air through the center portion of the fan. By directing the air through the center portion of the fan, the HVAC air is directed to a position below the fan blades. If cool air is directed by the HVAC system either immediately above or below the blades, the cool air may be pushed downward by the motion of the fan blades upon the cool HVAC air. This would act to further cool a person standing within the zone of the fan by introducing actual cool air in the space. The combination of cool air and the relative cooling effect of the fan blades greatly increases the beneficial effect of the fans. 
     Alternatively, when heated air is introduced by the HVAC system into the area immediately above or below the fan blade, and the fan is operating in the reversed position, the fan pulls the warmer air from a position under the fan upward and then distributes the warmer air situated at the ceiling to mix with the cooler air located at the floor to increase the actual temperature of the room. 
     The present invention may incorporate 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. The stepped design of the fan blade is described in patent application Ser. No. 14/814,161 and is incorporated in its entirety by reference herein. 
     One of the benefits of incorporating the HVAC delivery system of the present invention with 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 balanced 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. The heated or cooled HVAC air is introduced into the fan blades at, or in close proximity to 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 HVAC delivery system delivering air to the dead area provides for airflow directly under the fan. The stepped configuration of the leading edge of the fan blade even more dramatically impacts the airflow directly under the fan. 
     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. 
    
    
     
       DESCRIPTION OF THE FIGURES 
       Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the following drawings: 
         FIG. 1  is a perspective view of the fan of the present invention; 
         FIG. 2  is a bottom plan view of the fan; 
         FIG. 2( a )  is a section side elevation view of a fan of the present invention showing the HVAC system integral to the fan; 
         FIG. 2( b )  is a section side elevation view of a fan of the present invention with the fan moving in the reverse direction, directing air upward toward the ceiling; 
         FIG. 3  is a top plan view of a fan blade of the present invention showing the stepped design; 
         FIG. 3( a )  is a top plan view of an alternative design of the fan blade of the current invention that includes five steps; 
         FIG. 4  is a side view of the fan blade of the present invention; 
         FIG. 5  is a perspective view of a fan blade of the current invention showing three steps; 
         FIG. 5 a    is a perspective view of an alternate embodiment of the fan blade of the present invention; 
         FIG. 6  is graph of air speed versus distance from the center of the fan; 
         FIG. 7  is a cutout view of a offset motor gear box; 
         FIG. 8  is a side view of a flow diagram where the rotation of the fan blades force air in a downward direction; and 
         FIG. 9  is a side view of a flow diagram where the rotation of the fan blades force air in an upward direction. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION 
     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). Non-commercial, or residential fans typically have a span less than 8-feet. 
     In the preferred embodiment of the present invention, as shown in  FIGS. 1, 2, 2 ( a ) and  2 ( b ), the fan  10  is mounted to a ceiling  20 . The fan  10  is mounted to the ceiling  20  using a standard mount such as a universal I-Beam clamp with a swivel. The fan may also be mounted in conjunction with an HVAC system (not shown). 
     As shown in  FIGS. 1, 2, 2 ( a ) and  2 ( b ), the fan  10  includes an HVAC delivery system  500 . The HVAC delivery system  500 , comprise a generally hollow section  502  which connects to the HVAC system. In the preferred embodiment, the HVAC delivery system  500  is positioned along in close proximity to the centerline  515  of the fan. Air from the HVAC system is supplied from the HVAC system (not shown) to the hollow section  502  of the HVAC delivery system  500 . As shown in  FIG. 2( a ) , the air from the HVAC system passes from the inlet  504  of the HVAC delivery system  500 , to the lower outlet or lower exchanger  506  of the HVAC delivery system  500 . Air from the HVAC system may also be delivered above the plane formed by the fan blades  30  as shown by an upper air ducts or air exchanger  507 . The fan blades  32  act upon the cool air  507  delivered from the outlet  506  and the air ducts  501  of the HVAC delivery system  500  such that air  507  is pushed downward by the fan blades  32  toward the lower segment of a room. The gear mechanism  516  and gear motor  501  of the fan  10  may operate in a reverse manner to pull the air supplied from the outlet  506  of the HVAC delivery system  500  by the movement of fan blades  32 . As shown in  FIG. 2( b ) , the air from the HVAC system passes from the inlet of the HVAC delivery system  500 , to the lower outlet  506 , whereupon the fan blades  32  act upon the warm air  509  delivered from the outlet  506  such that the air  509  is pulled upward toward the ceiling of the room. The air ducts  501  are not shown in  FIG. 2( b ) , but may be employed if so desired. 
     The gear motor  501  and gear mechanism  516  is typically an off-set PM electromagnetic motor. The horsepower of the motor varies depending upon the diameter of the entire fan  10 . For example, an 8-foot and 12-foot fan typically has a 1 horsepower gear motor  501 . The 16-foot fan typically includes a 1.5 horsepower gear motor  501 , and a 20-foot and 24-foot fan typically has a 2.0 horsepower gear motor  501 . Attached to the gear motor  501  is a fan blade mount/gear  503  that has a centerline  515  at the center of the fan to which the fan blades  32  are mounted. The gear motor  501  operates in cooperation with the gear mechanism  516  and the blade mount/gear  503  to turn the fan blades  32 . The gear mechanism  516  may be offset from the centerline  515  of the fan. Alternatively, the gear mechanism  516  may be positioned along the centerline  515  of the fan.  FIGS. 2( a ) and 2( b )  show the gear mechanism  516  in the offset position relative to the centerline  515  of the fan. The position of the HVAC delivery system  500  in proximity to the centerline  515  is the important to the function of the invention. 
     The preferred embodiment shown in  FIGS. 1 and 2  includes five fan blades  30 , however, there may be a greater number of fan blades, or there may be less than five fan blades. Each fan blade  30  has a leading edge  32 , and a trailing edge  34  and an end cap  36 . The fan blade  30  includes a blade body  38 . The blade body  38  is typically made of an extruded aluminum alloy, but could be made of a composite metal, carbon fiber material, a graphite material, fiberglass, wood or other similar material. The leading edge  32  of the fan blade has steps  40 ,  42 ,  44  (as shown in  FIGS. 2 and 3 ) from the portion of the leading edge  32  fan blade  30  positioned closest to the centerline  15  of the fan blade mount  15 . 
     The stepped configuration of the leading edge  32  of the fan blade is shown in more detail in  FIGS. 2, 3, 4 and 5 . The leading edge  32  of the fan blade  30  has a first step  40 , a second step  42  and a third step  44 . The steps extend from the blade body  38 . The leading edge  32  of the fan blade  30 , including the first step  40 , the second step  42  and the third step  44 , are preferably made of an extruded polymer material, such as high-impact polystyrene, but may be constructed of a composite plastic material, graphite, fiberglass, carbon fiber, aluminum or any material having similar features and properties to the identified materials. 
     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.  FIG. 3( a )  shows a blade that has five steps. By way of example, a 20-foot diameter fan would have a fan blade  130  of approximately 10-foot in length  139 . The ratio of the steps in the preferred embodiment would be 5:4:3:2:1. Each step  140 ,  142 ,  144 ,  146 , and  148  would be approximately 2 feet in length  156 . The overall fan width  155  should not exceed 9-inches in the preferred embodiment. A fan blade  30  that exceeds a width of 9-inches may cause an undesirable load to be placed on the motor. It is, of course, possible for the distance to be greater than 9-inches if one chooses to construct a fan using a non-conventional fan motor. In the above example of the 5 step fan blade, the distance from the front edge of the fan body  38  to the leading edge of the step  40  should not necessarily exceed 3 inches. In the embodiment of a 5 step fan blade ( FIG. 3( a ) ), the distance of the first step  50  would be approximately 3-inches. Each step would then decrease by 6/10 of an inch. 
       FIG. 4  is a side view of one of the preferred embodiments of the fan blade of the present invention which has 3 steps. The blade  30  includes a leading edge  32 . The leading edge  32  includes a series of steps  40 ,  42  and  44 . The distance between the first step  40  and the second step  42  of the leading edge  32  is shown as  56 . Likewise, the distance between the second step  42  and the third step  44  is shown as  58 . The blade  30  has an upper portion  35  and a lower portion  37 . The blade  30  also has a rearward portion  34 . The steps  40 ,  42  and  44  along the leading edge  32  of the blade  30  provides vortex along the edge of the steps  60  and  62 . The vortex created at the edges of the steps  60  and  62  create a greater turbulent airflow below the fan. The vortex created at the edges of the steps  60  and  62  also provide for greater airflow velocity in the area near the centerline  15  of the fan. 
     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  FIG. 5( a ) , the steps  240 ,  242  and  244  have edges  260  and  262  that are at approximately a 90° angle to the leading edge  232  of the fan blade  230 . The configuration of the edges  260  and  262  does not affect the function of the fan blade  230 . 
     An actual embodiment of the preferred invention, without the HVAC delivery system  500 , was tested at a warehouse facility in Beaver Dam, Wis. The height of the facility was twenty-five feet from the floor to the ceiling. The high volume, 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  FIGS. 3 and 4 . The average velocity of the air was measured using a wind velometer gauge. The air velocity was measured at a height of 48-inches above the level of the floor. Measurements were taken at various distances, at approximately three foot intervals, from the centerline  18  of the fan. Measurements were taken at each location using the wind velometer gauge over a time period of approximately thirty seconds. Because the airflow is not constant, the maximum and minimum airflow measurements were recorded over the thirty second period. The maximum and minimum velocity readings over the thirty second period were averaged and are set forth in the chart below: 
                                             Distance from   Velocity           Center of Fan (Feet)   (Miles Per Hour)                                                    3   2.3           6   3.0           9   4.0           12   2.8           15   4.0           20   3.0           23   3.1           26   2.3           30   1.9           33   2.9           36   3.0           42   2.0           46   2.7           50   2.0           53   1.9           58   1.1           62   1.1                          FIG. 6  is a graph of the average velocity in MPH of airflow created by the circulation of the fan  10  utilizing the blades  30  of the preferred embodiment at various distances from the centerline  18  of the fan. As shown in  FIG. 6 , for example, at approximately 8-feet and 16-feet from the centerline  18  of the fan, the average velocity of airflow 48-inches above the ground was 4 miles per hour. The human body typically feels 6° to 10° F. cooler (Relative Temperature) than the ambient temperature of the air when the air is circulating at 4 miles per hour. At airflow at a velocity of 2 miles per hour, the human body fees 3 to 5° cooler than the ambient temperature of the air. The benefit of the fan design is a greater velocity of air circulation is achieved within close proximity to the centerline  14  of the fan.
 
     The design of the present invention of placing an HVAC delivery system  500  along, or in close proximity to, the centerline  515  of the fan achieves movement of the air exiting the outlet  506  (and air ducts  501 ) of the HVAC delivery system  500 . Cool air  507  (or heated air  509  if the fan is reversed) exiting the upper air exchanger  507  or lower exchanger  506  (and air ducts  501 ) of the HVAC delivery system  500  along the centerline  505  of the fan is disbursed along the fan blades  32 . Thus, the cooled air  507  (or heated air  509 ) interacts with the airflow created by the fan blades  32  to more evenly disbursed the cooled air  507  (or heated air  509 ) in the vicinity of the fan. 
     The stepped fan blade design has significant airflow coverage and overall air dispersion when used in connection with the HVAC delivery system  500  positioned along the centerline  515  of the fan. The fan of the current invention has minimal airflow dead spots, especially within close proximity to the centerline  515  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.