Patent Publication Number: US-2022235950-A1

Title: Energy recovery wheel assembly

Description:
PRIORITY CLAIM 
     This application claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Application Ser. No. 63/141,085, filed Jan. 25, 2021, which is incorporated by reference herein. This application incorporates by reference the subject matter of a copending application filed by the Applicant on Jan. 24, 2022 and entitled “Energy Recovery Array Wheel Array.” 
    
    
     BACKGROUND 
     The present disclosure relates to energy recovery devices, and particularly to energy recovery devices for recovering heat and/or moisture from an airflow. More particularly, the present disclosure relates to an energy recovery wheel that recovers heat and/or moisture from an airflow. 
     SUMMARY 
     According to the present disclosure, an energy recovery wheel assembly includes a support frame, a motor, and a wheel rotor. The support frame at least partially defines an air-supply section that supplies outdoor air into a building and an air-exhaust section that removes indoor air from the building. The motor is coupled to the support frame. The wheel rotor is coupled to the support frame and driven in rotation about an axis relative to the support frame by the motor. 
     In illustrative embodiments, the wheel rotor includes an outer case, a wheel mount coupled to the support frame, and energy absorption media located between the outer case and the wheel mount. The energy absorption media may be made up of a plurality of sheets. The energy absorption media may have a depth within a range of about 15 inches to about 40 inches. Each sheet may have a thickness within a range of about 0.003 inches to about 0.01 inches. 
     In illustrative embodiments, each sheet comprises at least one of aluminum, stainless steel, and copper. In illustrative embodiments, each sheet further comprises a desiccant coating. 
     In illustrative embodiments, the motor drives the wheel rotor to rotate at a rate of about 8 revolutions per minute or less. In illustrative embodiments, the rate is maintained when the wheel rotor is exposed to low temperature environments. 
     In illustrative embodiments, the wheel rotor is a first wheel rotor and the energy recovery wheel assembly further includes a second wheel rotor spaced apart from the first wheel rotor along the axis. In illustrative embodiments, the first wheel rotor is configured to rotate about the axis in a first direction and the second wheel rotor is configured to rotate about the axis in an opposite second direction. 
     In illustrative embodiments, the first wheel rotor is a sensible wheel rotor without any desiccant coating and the second wheel rotor includes a desiccant coating. In illustrative embodiments, the first wheel rotor is configured to rotate about the axis at a first rate and the second wheel rotor is configured to rotate about the axis at a second rate different than the first rate. 
     According to another aspect of the present disclosure, an energy recovery wheel assembly includes a support frame, a first wheel rotor, and a second wheel rotor. The support frame at least partially defines an air-supply section that supplies outdoor air into a building and an air-exhaust section that removes indoor air from the building. The first wheel rotor is coupled to the support frame and is configured to rotate about an axis relative to the support frame. The second wheel rotor is also coupled to the support frame and is configured to rotate about the axis relative to the support frame. 
     In illustrative embodiments, the first and second wheel rotors each include energy absorption media that is configured to transfer at least one of heat and moisture between air flowing through the air-supply section and air flowing through the air-exhaust section as the first and second wheel rotors are rotated about the axis. 
     In illustrative embodiments, the energy absorption media is made up of a plurality of sheets, the energy absorption media having a depth within a range of about 15 inches to about 40 inches, each sheet having a thickness within a range of about 0.003 inches to about 0.01 inches. 
     In illustrative embodiments, each sheet comprises at least one of aluminum, stainless steel, and copper. In illustrative embodiments, the first wheel rotor is configured to rotate about the axis in a first direction and the second wheel rotor is configured to rotate about the axis in an opposite second direction. In illustrative embodiments, the first wheel rotor is a sensible wheel rotor without any desiccant coating and the second wheel rotor includes a desiccant coating. 
     In illustrative embodiments, the first wheel rotor is configured to rotate about the axis at a first rate and the second wheel rotor is configured to rotate about the axis at a second rate different than the first rate. In illustrative embodiments, the first wheel rotor and the second wheel rotor are configured to rotate about the axis at a rate of about 8 revolutions per minute or less and the rate is maintained when the wheel rotor is exposed to low temperature environments. 
     According to another aspect of the present disclosure, a method of recovering energy from air in a building includes displacing outdoor air from outside of the building through an air-supply section of an air handling unit toward an interior of a building. The method may further include displacing indoor air from the interior of the building through an air-exhaust section of the air handling unit that is separate from the air-supply section. The method may further include rotating a first wheel rotor about an axis that extends parallel to and is located between the air-supply section and the air-exhaust section. The method may further include rotating a second wheel rotor about the axis. 
     In illustrative embodiments, the first and second wheel rotors each include energy absorption media that is configured to transfer at least one of heat and moisture between air flowing through the air-supply section and air flowing through the air-exhaust section as the first and second wheel rotors are rotated about the axis. 
     In illustrative embodiments, the energy absorption media is made up of a plurality of sheets, the energy absorption media having a depth within a range of about 15 inches to about 40 inches, each sheet having a thickness within a range of about 0.003 inches to about 0.01 inches. 
     In illustrative embodiments, the first wheel rotor is rotated about the axis in a first direction and the second wheel rotor is rotated about the axis in an opposite second direction. In illustrative embodiments, the first wheel rotor is configured to rotate about the axis at a first rate and the second wheel rotor is configured to rotate about the axis at a second rate different than the first rate. 
     Additional features of the present disclosure will become apparent to those skilled in the art upon consideration of illustrative embodiments exemplifying the best mode of carrying out the disclosure as presently perceived. 
    
    
     
       BRIEF DESCRIPTIONS OF THE DRAWINGS 
       The detailed description particularly refers to the accompanying figures in which: 
         FIG. 1  is a perspective view of an energy recovery wheel assembly including a support frame, a motor, and a wheel rotor that is driven in rotation by the motor relative to the support frame to recover heat and/or moisture as indoor air and outdoor air pass through the wheel rotor; 
         FIG. 2  is a perspective view of another embodiment of an energy recovery wheel assembly including two wheel rotors arranged in series along the air flow paths; and 
         FIG. 3  is a perspective view of another embodiment of an energy recovery wheel assembly including three wheel rotors arranged in series along the air flow paths. 
     
    
    
     DETAILED DESCRIPTION 
     An energy recovery wheel assembly  10  in accordance with the present disclosure, includes a support frame  12 , a motor  14 , and the wheel rotor  16  as shown in  FIG. 1 . The support frame  12  is configured to support the wheel rotor  16  within an air handling unit  100  that includes an air-supply section  102  that supplies outdoor air into a building and an air-exhaust section  104  that removes indoor air from the building at the same time. The motor  14  is configured to drive and control rotation of the wheel rotor  16  relative to the air handling unit  100 . The energy recovery wheel assembly  10  is arranged to lie in both the air-supply section  102  and the air-return section  104  and is configured to move heat and/or moisture between the supply air and the exhaust air as the indoor air is exchanged with outdoor air by the air handling unit  100 . 
     The support frame  12  may form a part of the air handling unit  100  or be attached thereto and includes an outer support frame  18 , a crossbeam  20 , and a seal  22  as shown in  FIG. 1 . The support frame  12  is sized to accommodate the wheel rotor  16  within a space  26  provided by the outer support fame  18 . The outer support frame  18  defines a prism that is sized to fit within the air handling unit to position the wheel rotor  16  relative to the air-supply section and the air-exhaust section. The crossbeam  20  extends from one side of the outer support frame  18  to an opposite side of the outer support frame  18  at a boarder to the both the air-supply section and the air-exhaust section. The seal  22  is coupled to the crossbeam  20  to seal between the air-supply section and the air-exhaust section of the air handling unit while the energy recovery wheel  10  rotates relative to the support frame  12 . 
     The wheel rotor  16  rotates about a wheel rotational axis  24  relative to the outer support frame  18  and the crossbeam  20 . The wheel rotor  16  includes an outer case  30 , a wheel mount  32 , and energy absorption media  34  between the outer case  30  and the wheel mount  32 . The outer case  30  is coupled to the motor  14  and is driven by the motor  14  to rotate the wheel rotor  16  about the wheel rotational axis  24  when the wheel rotor  16  is being used. The wheel mount  32  is coupled in rotative bearing engagement with a bearing  36  mounted on the crossbeam  20  to allow the wheel rotor  16  to rotate relative to the support frame  12 . The energy absorption media  34  is configured to absorb heat and/or moisture from the air passing through one of the air-supply section and the air-exhaust section and transfer the heat and/or moisture to the other of the air-supply section and the air-exhaust section to reduce energy losses from the air in the building as outdoor air is brought into the building. The wheel rotor  16  may also include a plurality of spokes  38  that extend between the wheel mount  32  and the outer case  30 . 
     The energy absorption media  34  defines a plurality of air channels to allow flow of air through the energy absorption media  34 . The energy absorption media  34  captures and releases heat and/or moisture from the air flowing through the air channels. The energy absorption media  34  may be made from any suitable material such as aluminum, stainless steel, copper, a ceramic, or any other suitable material. In some embodiments, the energy absorption media  34  may include a desiccant coating, such as a molecular sieve desiccant, a silica gel desiccant, MS3A desiccant, or a passive desiccant to capture and release moisture from the air flowing through the air channels. Accordingly, the expression “energy recovery wheel assembly” should be interpreted to include, without limitation thereto, a rotary wheel, a thermal wheel, a sensible wheel, a heat wheel, a desiccant wheel, a dehumidification wheel, a heat and/or moisture recovery wheel, a total energy recovery wheel, a enthalpy wheel, a regeneratable rotary dehumidification wheel, a rotary enthalpy wheel, a rotating wheel exchanger and the like. 
     The wheel rotor  16  provides a higher effectiveness or efficiency for the assembly than other energy recovery wheels and may be used in low outdoor temperature settings where other energy recovery wheels would freeze or would require a frost system to remove frost and ice. The energy absorption media  34  is sized and/or constituted to increase the thermal inertia and/or mass of the wheel rotor  16  compared to other energy recovery wheels to achieve the higher effectiveness or efficiency without using any frost system in colder environments. Example 1 below discusses the wheel rotor  16  of the illustrative embodiment while Example 2 below discusses a comparative energy recovery wheel with a lower effectiveness and that includes an anti-frost system to operate in cold environments (i.e. below 32 degrees Fahrenheit). 
     Example 1 is described below. The term “about” is used to account for manufacturing tolerances and includes values within about 5 percent of the stated value. 
     The energy absorption media  34  has a diameter  40  and a depth  42  as shown in  FIG. 1 . In some embodiments, the diameter  40  is within a range of about 12 inches to about 150 inches. In some embodiments, the diameter  40  is within a range of about 48 inches to about 120 inches. In some embodiments, the diameter  40  is about 48 inches. In some embodiments, the diameter  40  is about 54 inches. In some embodiments, the diameter  40  is about 62 inches. In some embodiments, the diameter  40  is about 70 inches. In some embodiments, the diameter  40  is about 78 inches. In some embodiments, the diameter  40  is about 88 inches. In some embodiments, the diameter  40  is about 96 inches. In some embodiments, the diameter  40  is about 96 inches. In some embodiments, the diameter  40  is about 108 inches. In some embodiments, the diameter  40  is about 120 inches. In some embodiments, the diameter  40  is greater than 120 inches. 
     In some embodiments, the depth  42  of the energy absorption media  34  is within a range of about 15 inches to about 50 inches. In some embodiments, the depth  42  is about 15 inches. In some embodiments, the depth  42  is about 18 inches. In some embodiments, the depth  42  is about 20 inches. In some embodiments, the depth  42  is about 25 inches. In some embodiments, the depth  42  is about 30 inches. In some embodiments, the depth  42  is about 35 inches. In some embodiments, the depth  42  is about 40 inches. In some embodiments, the depth  42  is about 45 inches. In some embodiments, the depth  42  is about 50 inches. In some embodiments, the depth  42  is greater than 50 inches. 
     The energy absorption media  34  can be comprised of corrugated or fluted sheet material. The sheet material defines a thickness perpendicular to the wheel rotational axis  24 . In some embodiments, the thickness of each sheet is within a range of about 0.002 inches to about 0.01 inches. In some embodiments, the thickness of each sheet is within a range of about 0.003 inches to about 0.008 inches. In some embodiments, the thickness of each sheet is about 0.003 inches. In some embodiments, the thickness of each sheet is greater than 0.003 inches. 
     In one nonexclusive example, an aluminum energy absorption media  34  can have a thickness of about 0.002 and a depth  42  of about 20-30 inches. In a different nonexclusive example, an aluminum energy absorption media  34  can have a thickness of about 0.002 and a depth  42  of about 20 inches. In another nonexclusive example, an aluminum energy absorption media  34  can have a thickness of about 0.002 and a depth  42  of about 25 inches. In yet another nonexclusive example, an aluminum energy absorption media  34  can have a thickness of about 0.002 and a depth  42  of about 30 inches. Yet another nonexclusive example includes an aluminum energy absorption media  34  having a thickness of about 0.003 and a depth  42  of about 20 inches 
     If this invention is used with a plurality of wheel rotors, as discussed below, with one of the wheel rotors within the parameters discussed above, then at least one of the other of the plurality of wheel rotors can comprise an aluminum energy absorption media  34  can have a depth  42  of about less than 15 inches 
     Example 2 is described below. The diameter of the comparative energy recovery wheel in Example 2 may be the same as the diameter  40  of the wheel rotor  16 . 
     In some embodiments, the depth of the energy absorption media of the comparative energy recovery wheel is within a range of about 6 inches to about 14 inches. In some embodiments, the depth of the energy absorption media of the comparative energy recovery wheel is about 10 inches. Thus, the depth of the energy absorption media of the comparative energy recovery wheel is less than the depth  42  of the illustrative embodiment in Example 1. 
     Each sheet included in the energy absorption media of the comparative energy recovery wheel includes a thickness of about 0.002 inches. Thus, the thickness of each sheet included in the comparative energy recovery wheel is less than the thickness of each fluted sheet of the illustrative embodiment in Example 1. 
     Because the depth of the energy absorption media and the thickness of each sheet in Example 2 is less than the depth  42  and thickness of each sheet in Example 1, Example 2 has a lower energy recovery effectiveness. Additionally, the ability of the energy recover wheel of Example 1 to hold heat energy longer than the energy recovery wheel of Example 2 permits the energy recovery wheel of Example 1 to avoid frosting in low temperature environments whereas the energy recovery wheel of Example 2 might require an anti-frost system, such as a variable frequency drive motor that decreases the rotation speed of the energy recovery wheel to reduce frost build-up on the energy absorption media. The higher thermal inertia of the wheel rotor  16  of Example 1 may eliminate the need for an anti-frost system. The wheel rotor  16  of the illustrative embodiment may also omit spokes  38  because of the increase in reinforcement provided by the greater thickness of each sheet in the energy absorption media  34  compared to Example 2. 
     The motor  14  of energy recovery wheel assembly  10  is configured to rotate the wheel rotor  16  at a rate within a range of about 0.2 revolutions per minute (RPM) to about 1 RPM. In some embodiments, the motor  14  rotates the wheel rotor  16  within a range of about 0.4 RPM to about 0.8 RPM. In some embodiments, the motor  14  rotates the wheel rotor  16  within a range of about 0.5 RPM to about 0.7 RPM. In some embodiments, the motor  14  rotates the wheel rotor  16  at about 0.6 RPM. In some embodiments, the motor  14  rotates the wheel rotor  16  at about 8 RPM or lower. 
     The RPM of the wheel rotor  16  is configured to remain constant even in low temperature environments (i.e. below 32 degrees Fahrenheit). In contrast, the comparative energy recovery wheel is rotated at about 20 RPM but can be lowered to a lower RPM in low temperature environments so that frost does not build up on the energy absorption media. This lowers the effectiveness of the comparative energy recovery wheel whereas the wheel rotor  16  of the illustrative embodiment maintains its effectiveness without reducing it&#39;s RPM even in low temperature environments and may consume less power due to the lower RPM. 
     The air handling unit  100  includes a housing  106 , an air-movement system  108 , and the energy recovery wheel assembly  10  as shown in  FIG. 2 . The housing  106  includes an outer shell  110  (only a portion is shown in  FIG. 2 ) defining an interior space  112  and a divider wall  114  located within the interior space  112  to divide the interior space  112  into the air-supply section  104  and the air-exhaust section  106 . The air-movement system  108  includes a first blower  116  configured to displace air through the air-supply section  102  from an exterior of the building to an interior of the building and a second blower  118  configured to displace through the air-exhaust section  104  from the interior of the building to the exterior of the building. The energy recovery wheel assembly  10  lies in the interior space  112  in both the air-supply section  102  and the air-exhaust section  104 . The divider wall  114  passes generally through a center of the energy recovery wheel assembly  10  such that about one-half of the energy recovery wheel assembly  10  lies in the air-supply section  102  and the other half lies in the air-exhaust section  104 . 
     In some embodiments, a plurality of wheel rotors may be arranged in series with one another to further increase efficiencies of the air handling unit  100 . Another embodiment of an energy recovery wheel assembly  200  including multiple wheel rotors is shown in  FIG. 2 . The energy recovery wheel assembly  200  is substantially similar to energy recovery wheel assembly  10 . Accordingly, similar reference numbers in the 200 series are used to describe similar features between energy recovery wheel assembly  200  and energy recovery wheel assembly  10 . The disclosure of energy recovery wheel assembly  10  is incorporated by reference for energy recovery wheel assembly  200 . 
     The energy recovery wheel assembly  200  includes a support frame  212 , at least one motor  214 , and a plurality of wheel rotors  216 ,  217  arranged in series with each other along a common axis  218 . The support frames  212  and the motors  214  are substantially similar to support frame  12  and motor  14  of energy recovery wheel assembly  10 . The wheel rotors  216 ,  217  are spaced apart from one another along the axis  218  and each wheel rotor  216 ,  217  may be substantially similar to wheel rotor  16  shown in  FIG. 1 . Arranging multiple wheel rotors in series increases overall efficiencies of the energy recovery wheel assembly  200  and increases the functionality and/or capabilities of the air handling unit  100 . 
     In the illustrative embodiment, each wheel rotor  216 ,  217  is driven in rotation about the common axis  218  by respective motors  214  as shown in  FIG. 2 . The wheel rotors  216 ,  217  may rotate about the axis  218  in the same direction. In some embodiments, the first wheel rotor  216  is configured to rotate about the axis  218  in a first direction and the second wheel rotor  217  is configured to rotate about the axis  218  in an opposite second direction. Such an embodiment may increase an efficiency of heat and/or moisture transfer provided by the energy recovery wheel assembly  200 . 
     In some embodiments, the first wheel rotor  216  may rotate about the axis  218  at a first rate and the second wheel rotor  217  may rotate about the axis  218  at a second rate different than the first rate. For example, the rate of rotation of each wheel rotor  216 ,  217  may be increased or decreased relative to one another based on indoor and/or outdoor air conditions (i.e. temperature/humidity). 
     Each wheel rotor  216 ,  217  may include a different type of energy absorption media to provide the energy recovery wheel assembly  200  with more functionality. For example, the first wheel rotor  216  may be a sensible only wheel rotor without any desiccant coating while the second wheel rotor includes a desiccant coating for moisture recovery and transfer. Additionally, the first wheel rotor  216  may have a first sheet thickness or depth  42  while the second wheel rotor  217  has a second sheet thickness or depth  42  different than the first sheet thickness or depth  42 . Thus, each wheel rotor  216 ,  217  can be designed for a particular purpose without various features competing with one another or affecting an efficiency provided by one another. 
     In illustrative embodiments, the air handling unit  100  can include an energy recovery wheel assembly  300  having any number of wheel rotors in series with one another. For example, the air handling unit can include three wheel rotors  316 ,  317 ,  318  arranged along a common axis. Each wheel rotor  316 ,  317 ,  318  may be substantially similar to wheel rotor  16  shown in  FIG. 1 . Each wheel rotor  316 ,  317 ,  318  may be rotated at a different rate or direction and may include different features relative to one another to maximize the total efficiency of the air handling unit  100 . 
     Energy recovery wheel assemblies  10 ,  200 ,  300  may be controlled by a control system having a microprocessor and a memory storage device. The microprocessor may be any computing device that is capable of receiving signals and operating the energy recovery wheel assemblies  10 ,  200 ,  300  (and air handling unit  100 ) in response to the signals. The memory storage device includes stored instructions that, when executed by the microprocessor, cause the energy recovery wheel assemblies  10 ,  200 ,  300  to operate in response to one or more sensed conditions or inputs.