Abstract:
An energy recovery system includes a heating or cooling system and an energy recovery ventilator operably connected to a component of the heating or cooling system. The energy recovery ventilator includes a supply port extending into the component to provide a supply of fresh airflow from the energy recovery ventilator to the component for use by the component. A return port extends into the component configured to receive a flow of stale air from the component while minimizing ingestion of the fresh air flow from the component into the return port. A method of operating an energy recovery system includes flowing a flow of fresh air from an energy recovery ventilator through a supply port into a component of a heating or cooling system. Stale air is flowed from the component through a return port into the energy recovery ventilator, preventing fresh air from recirculating through the return port.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    Embodiments relate generally to heat and mass exchangers and, more particularly, to an energy recovery ventilator (“ERV”) that attaches directly to an existing furnace, fan coil or air handler and uses two duct connections for recovering energy from indoor air. 
         [0002]    An ERV is generally used with a heating or cooling system to exhaust stale air from a stale air space to a fresh air space and bring in fresh air from the fresh air space to the stale air space while exchanging heat or cool energy, thereby reducing heating or cooling requirements. Typically, an ERV includes a heat and mass exchanger contained in a housing for exchanging heat or cool energy. The exchanger may be rotating or stationary. When the ERV is used with a heating or cooling system, an outside air stream ducted from the outdoors and a stale room air stream from the return air duct or furnace, fan coil, or air handler separately enter the ERV and pass through the heat and mass exchanger. Within the heat and mass exchanger, energy from the stale room air stream is transferred either to or from the outside air stream. The outside air stream then exits the ERV to the supply air duct or furnace, fan coil, or air handler as a fresh air stream. The stale room air stream then exits the ERV to the outdoors through a duct as an exhaust room air stream. 
         [0003]    Most residential ERVs are mounted on a wall or ceiling and generally require four duct pipes to exchange cool or heat energy with an air handler system. In an example, the outside air stream and the stale room air stream enter the housing through duct pipes connected to two air flow openings in the housing. The fresh air stream and the exhaust room air stream exit the housing through two other duct pipes connected to two other air flow openings in the housing. These ERVs are standalone heat and mass exchangers that are remotely mounted from the heating or cooling system and are not designed to be connected directly to a furnace or an air handler in a heating or cooling system. As connected to the heating or cooling system, this ERV is costly and cumbersome to install as it requires the installation of four separate duct pipes to carry each air stream to or from the fresh air or stale air spaces. Moreover, these ERVs require low voltage wall controls and an available power receptacle, which further complicates the installation process. 
         [0004]    Other ERV&#39;s are configured to connect directly to a furnace or air handler blower compartment, eliminating the need for the four duct pipes. These ERV&#39;s, however, are prone to allow increased levels of stale air recirculation in the heating or cooling system. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0005]    According to one aspect of the invention, an energy recovery system includes a heating or cooling system and an energy recovery ventilator operably connected to a component of the heating or cooling system. The energy recovery ventilator includes a supply port extending into the component to provide a supply of fresh airflow from the energy recovery ventilator to the component of the heating or cooling system for use by the component. A return port extends into the component configured to receive a flow of stale air from the component while minimizing ingestion of the fresh air flow from the component into the return port. 
         [0006]    According to another aspect of the invention, a method of operating an energy recovery system includes flowing a flow of fresh air from an energy recovery ventilator through a supply port into a component of a heating or cooling system for use by the component. Stale air is flowed from the component through a return port into the energy recovery ventilator. The flow of fresh air is prevented from recirculating through the return port. 
         [0007]    These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which: 
           [0009]      FIG. 1  is a view of an embodiment of an energy recovery ventilator (ERV); 
           [0010]      FIG. 2  is a view of another embodiment of an ERV; 
           [0011]      FIG. 3  illustrates an embodiment of an ERV connected to a heating and cooling system; 
           [0012]      FIG. 4  illustrates embodiments of fresh air and return air ports between an embodiment of an ERV and a heating and cooling system; 
           [0013]      FIG. 5  illustrates other embodiments of fresh air and return air ports between an embodiment of an ERV and a heating and cooling system; 
           [0014]      FIG. 6  illustrates still other embodiments of fresh air and return air ports between an embodiment of an ERV and a heating and cooling system; 
           [0015]      FIG. 7  illustrates yet other embodiments of fresh air and return air ports between an embodiment of and ERV and a heating and cooling system; and 
           [0016]      FIG. 8  illustrates an alternate view of the embodiments of  FIG. 7 . 
       
    
    
       [0017]    The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0018]    An embodiment of an energy recovery ventilator (“ERV”) for use with a heating or cooling system includes a generally rectangular housing that may be directly attached to an existing furnace/fan coil in the system. The ERV includes a fresh air intake duct and an exhaust air duct. In an embodiment, an outside air stream enters the ERV through the fresh air intake duct while stale conditioned air from an interior conditioned air space is exhausted through the exhaust air duct. The ERV includes a heat and mass exchange device for recovering energy from the stale conditioned air prior to exhausting the stale conditioned air to an outside air space. In an embodiment, the ERV may be used with a wall penetration that provides a simplified duct assembly for connecting the ducts to the outside air space. In an embodiment, the ERV may be electrically wired directly, via a wire line, to a power supply in the heating and cooling system in order to energize the ERV and eliminate providing a standalone power supply. In one non-limiting embodiment, a two-wire line may be used to simplify the electrical connection to the heating or cooling system. But, in other embodiments, any number of wire-lines may be used to electrically connect the ERV to the heating and cooling system. The ERV may also be connected to a furnace/fan coil controller in the heating and cooling system for controlling the operation of the ERV without requiring an additional dedicated controller for ERV control and operation. 
         [0019]    Referring now to the drawings,  FIGS. 1-2  illustrate an ERV  2  used in connection with a heating or cooling system  18  for circulating fresh air from the outdoors while recovering energy from stale conditioned air according to an embodiment of the invention. Particularly, the ERV  2  includes a generally rectangular housing  4  fitted with a fresh air intake duct  6  and an exhaust air duct  10 . The fresh air intake duct  6  and exhaust air duct  10  are coupled to selectively movable dampers  25 ,  26 , respectively. The dampers  25 ,  26  are selectively controllable by a furnace/fan coil controller (not shown) in response to signals such as, for example, signals indicative of temperature or humidity that are received from sensors inside the ERV  2  or inside the interior conditioned space. In some non-limiting examples, the dampers  25 ,  26  may be a valve or plate that stops or regulates the flow of air entering or exiting ERV  2  through the respective ducts  6 ,  10 . The ERV  2  also includes a heat and mass exchange device  14  such as, in some non-limiting examples, a honeycomb heat exchanger or a brazed-plate heat exchanger for recovering energy from stale conditioned air. The stale conditioned air is received through a return port  20 , which is in fluid communication with an air return duct coupled to the heating or cooling system  18 . A fan  16  is coupled to the heat exchange device  14  in order to induce air movement through the heat exchange device  14  as well as induce to a positive air pressure in the furnace/fan coil of the heating or cooling system  18 . In an embodiment, as shown with reference to  FIG. 2 , a fan or blower  29  may also be fluidly coupled to the fresh air intake duct to either induce air intake from an outdoor air space  24  or control the air flow rate entering the ERV  2  from the outdoor air space  24 . 
         [0020]    A filter element  27  is coupled to duct connection  6  in order to filter out any dust, debris, pollutants, or the like from the outside air stream  8 . Additionally, in an embodiment, a filter element  28  is coupled to a return port  20  to filter an exhaust air stream  12  that is received from a return air duct that is in fluid communication with an interior conditioned air space. In another embodiment, a filter element, which is substantially similar to filter element  28 , may be coupled to supply port  22  near or attached to the face of the heat exchanger  14  in order to filter the outside air stream  8 . In operation, an outside air stream  8  from, for example, an outdoor air space  24  enters the ERV  2  through duct  6  while stale conditioned air from an interior conditioned air space is received by ERV  2  and exhausted as an exhaust air stream  12  through the exhaust air duct  10 . Dampers  25 ,  26  control the air flow rate entering or exiting the ERV  2  or, alternatively, Dampers  25 ,  26  may be closed to bypass the ERV  2 . The outside air stream  8  circulates through the heat exchange device  14  where energy exchange takes place within the heat exchange device  14 . The extracted energy is transferred to the outside air stream  8  and it enters the heating and cooling system  18  as a fresh air stream through the supply port  22 . 
         [0021]    In an embodiment, as shown in  FIGS. 1-2 , the ERV  2  may be electrically wired directly, via a two-wire line, to the heating and cooling system  18  in order to energize ERV  2 . The direct wiring eliminates need for providing an additional energizing power supply for energizing electrical components of the ERV  2 . Also, the ERV may be selectively and electrically coupled to a controller (not shown) located in, for example, an electronics circuit board of the heating and cooling system  18 . The controller (not shown) controls operation of the ERV  2  while also eliminating a need for an additional controller, thereby simplifying the installation as well as reducing the costs associated with installation. In an example, the controller may operate the ERV  2  while the furnace/fan coil air circulation blower is on in order to provide a desired ventilation rate through the heating and cooling system  18 . In another example, the controller may operate the ERV  2  for a portion of each hour based on the desired ventilation rate and the air flow capacity of the ERV  2 . In an embodiment, the controller includes a microprocessor preprogrammed with software programs that is stored in nonvolatile memory for executing algorithms to provide the ERV  2  with a variety of operation modes and control sequences as indicated above. 
         [0022]    In another embodiment, shown in  FIGS. 1-2 , the ERV  2  may be directly attached to, for example, an air circulation blower compartment of a furnace/fan coil of the heating and cooling system  18  through bolts, screws, or the like. But, in another non-limiting embodiment, the ERV  2  may be attached to a return air duct of an air handler without departing from the scope of the invention. In an embodiment, the ERV  2  may be electrically connected to a power supply as well as to a controller of the furnace/fan coil, thereby eliminating a need for an additional power receptacle or a dedicated controller, respectively. In an embodiment, the heating and cooling system  18  may include fans (e.g., blowers, air handlers, and the like) to communicate air flow from an interior air space to the ERV  2 . Other system components such as dampers, filters, additional fans, refrigeration and/or heating/dehumidification (e.g., economizer heat exchangers, heat rejection heat exchangers, and gas coolers/condensers), heat absorption heat exchangers (evaporator) may also be provided. In operation, outside air stream  8  enters the housing  2  through the duct connection  6  while stale conditioned air from the interior conditioned air space passes through the heat exchange device  14 . The heat exchange device  14  extracts energy from the stale conditioned air and exhausts the stale conditioned air as an exhaust air stream  12  from the ERV  2 . The outside air stream  8  circulates through the heat exchange device  14  where energy is transferred to the outside air steam  8  within the heat exchange device  14 . The outside air stream  8  receives the extracted energy and enters the heating and cooling system  18  as a fresh air stream through the supply port  22 . Further, stale conditioned air  12  is extracted from, in one non-limiting example, a return air duct that is directly connected to a conditioned air space. The stale conditioned air  12 , driven by fan  16 , enters the ERV  2  through return port  20 , circulates through the heat exchange device  14 , and exits the ERV  2  through duct connection  10 . 
         [0023]      FIG. 3  illustrates an elevation view of an ERV  2  that is in direct air flow communication with a furnace/fan coil  30  of system  18  according to another embodiment of the invention. As shown, the ERV  2  is sized to be directly connected to a circulation air blower compartment  32  of furnace/fan coil  30  and receives an air flow from the compartment  32  for energy recovery and recirculation to the interior conditioned air space  50 . The ERV  2  includes a fresh air intake duct  6  and an exhaust air duct  10 . The ERV  2  also includes a return port  20  and a supply port  22  that are in direct communication with the circulation air blower compartment  32 . The ERV  2  is shown installed in a vertical orientation directly coupled to furnace/fan coil  30 , which is also vertically oriented. But, in another embodiment, ERV  2  may be installed in a horizontal orientation in order to be coupled to a corresponding horizontally oriented heating and cooling system  18  without departing from the scope of the invention. A stale conditioned air stream  42  from an interior conditioned air space  50  enters system  18  through the return air duct  36 . In an embodiment, an air cleaner such as, for example, an air purifier  38  is provided to filter the stale conditioned air stream  42  and communicate a filtered air stream  52  to the negative pressure chamber of circulation air blower compartment  32 . In another embodiment, an air filter element (not shown) may be provided in lieu of the air purifier  38  in order to filter the stale conditioned air stream  42 . The filtered air stream  52  enters the ERV  2  through return port  20  whereby energy is extracted by the heat and mass exchange device  14  (shown in  FIGS. 1-2 ) prior to exiting the ERV  2  to the outdoor air space via duct  10 . This extracted energy is transferred to an outside air stream  8  (shown in  FIGS. 1-2 ) that enters the ERV  2  through intake duct  6 . The outside air stream  8  (shown in  FIGS. 1-2 ) is further communicated to the compartment  32  as a fresh air stream  46  through supply port  22 . The fresh air stream  46  mixes with the filtered air stream  52  in the compartment  32 . The circulation air blower  33  creates a positive pressure in a furnace/fan coil compartment  35 . The positive pressure overcomes the negative pressure in the circulation air blower compartment  32  and forces the mixed air from compartment  32  through the evaporator coil compartment  34  for heat-exchange within the evaporator coil compartment  34 . The mixed air is forced out of evaporator coil compartment  34  and through the air supply duct  40  as conditioned filtered air  48  in order to condition the interior conditioned air space  50 . It is to be appreciated that the ERV  2  mounts directly to the furnace/fan coil  30  in order to exhaust filtered air stream  52  from air blower compartment  32  while overcoming the negative static pressure in the blower air compartment  32 . 
         [0024]    Referring to  FIG. 4 , an embodiment of a supply port  22  and return port  20  is shown. The supply port  22  and the return port  20  extend through the ERV housing  4  and into the blower compartment  32 , and are secured to one or both of the housing  4  or the blower compartment  32  by, for example, a snap fit. Alternatively, the supply port  22  and/or the return port  20  are secured to the housing  4  or the blower compartment  32  by fasteners such as screws, pins or the like. The ports  20  and  22  shown in  FIG. 4  have are configured to direct flow in a selected direction and have, for example, an elbow-shaped cross-section. If the selected direction is changed, the flow may be redirected by rotating the ports  20  and  22  in openings through which they extend. The ports  20  and  22  are positioned to reduce recirculation of stale air through the heating and cooling system  18 , either through their orientation as above, or through their position in the ERV housing  4 , or both. As shown in  FIG. 4 , the supply port  22  and the return port  20  are oriented to ensure that the fresh air stream  46  flowing through the supply port  22  into the blower compartment is directed away from the return port  20  to minimize reingestion of fresh air stream  46  into the return port  20 , and maximizing filtered stale airstream  52  flowed through the return port  20  from the blower compartment  32  and into the ERV  2 . 
         [0025]    In other embodiments, as shown in  FIG. 5 , the supply port  22  and the return port  20  are triangular in cross-section. The triangular cross-section increases the flow path size for the fresh air stream  46  and the filtered stale airstream  52  to and from the blower compartment  32 . Increasing the flowpath size beneficially increases a rate of which the fresh air stream  46  can be delivered to the blower compartment  32  as well as increasing circulation of the filtered stale airstream  52  from the blower compartment  32  into the ERV  2  via the return port  20 . As shown in  FIG. 6 , in some embodiments the return port  20  includes a shield  70  secured to the return port  20 . The shield  70  is also triangular in shape and includes a shield opening  72  facing substantially downward into the blower compartment  32 . The shield  70  having the downward-facing shield opening  72  reduces recirculation of the fresh air stream  46  into the return port  20  by drawing from a lower perimeter  74  of the blower compartment  32 , reducing opportunities for the fresh air stream  46 , which is urged substantially upward by the blower  33 . 
         [0026]    Referring now to  FIG. 7 , in some embodiments, the ERV  2  is operably connected to a return air duct  36 , as an alternative to being connected to the blower compartment  32 . In the embodiment of  FIG. 7 , a stale air stream  42  is directed through the return air duct  36  toward the ERV  2 . At least a portion of the stale airstream  42  is directed into the return port  20  of the ERV  2  and into the ERV  2 , while the fresh airstream  46  is directed into the return air duct  36  through the supply port  22  toward the air purifier  38  and the blower compartment  32 . The supply port  22  and return port  20  are configured and located to prevent reingestion of the fresh airstream  46  into the return port  20 . As shown in the embodiment of  FIG. 7 , the return port  20  is located upstream of the supply port  22  in the return air duct  36 . Further, in some embodiments, as shown in  FIG. 8 , the return port  20  may include a shield  70  with an upstream-facing shield opening  72  to further restrict recirculation of the fresh airstream  46  into the return port  20 . 
         [0027]    While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.