Energy recovery ventilator

An energy recovery system includes a heating and cooling system having a controller and a furnace or fan coil in fluid communication with each of a return air duct and a supply air duct; and an energy recovery ventilator (ERV) having an intake air duct and an exhaust air duct, the ERV being energized by a direct electrical connection to the heating and cooling system. The return air duct is operable to receive stale conditioned air from a conditioned air space while the controller is configured for controlling the ERV to transfer energy from the stale conditioned air to an outside air stream.

FIELD OF INVENTION

This invention relates generally to heating 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.

DESCRIPTION OF RELATED ART

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 exchanger contained in a housing for exchanging heat or cool energy. When the ERV is used with a heating or cooling system, an outside air stream from the outdoors and a stale room air stream from the return air duct separately enter the ERV and pass through the heat exchanger. Within the heat 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 return air duct as a fresh air stream. The stale room air stream then exits the ERV to the outdoors as an exhaust room air stream.

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 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 with an available power receptacle, which further complicates the installation process.

BRIEF SUMMARY

According to one aspect of the invention, an energy recovery system includes a heating and cooling system including a controller and a furnace or fan coil in fluid communication with each of a return air duct and a supply air duct; an energy recovery ventilator (“ERV”) including an intake air duct and an exhaust air duct, the ERV being energized by a direct electrical connection to the heating and cooling system. The return air duct is operable to receive stale conditioned air from a conditioned air space while the controller is configured for controlling the ERV to transfer energy from the stale conditioned air to an outside air stream.

According to another aspect of the invention, a method of recovering energy with a heating and cooling system including an ERV coupled to a furnace or fan coil; receiving stale conditioned air from a conditioned air space; energizing the ERV via a direct electrical connection to the heating and cooling system; controlling a transfer of recovered energy from the stale conditioned air to an outside air stream; and communicating the outside air stream to the furnace or fan coil as a fresh air stream. Also, the heating and cooling system comprises a return air duct, a supply air duct, and a controller.

Other aspects, features, and techniques of the invention will become more apparent from the following description taken in conjunction with the drawings.

DETAILED DESCRIPTION

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 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.

Referring now to the drawings,FIGS. 1-2illustrate an ERV2used in connection with a heating or cooling system18for circulating fresh air from the outdoors while recovering energy from stale conditioned air according to an embodiment of the invention. Particularly, the ERV2includes a generally rectangular housing4fitted with a fresh air intake duct6and an exhaust air duct10. The fresh air intake duct6and exhaust air duct10are coupled to selectively movable dampers25,26, respectively. The dampers25,26are 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 ERV2. In some non-limiting examples, the dampers25,26may be a valve or plate that stops or regulates the flow of air entering or exiting ERV2through the respective ducts6,10. The ERV2also includes a heat exchange device14such 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 port20, which is in fluid communication with an air return duct coupled to the heating or cooling system18. A fan16is coupled to the heat exchange device14in order to induce air movement through the heat exchange device14as well as induce to a positive air pressure in the furnace/fan coil of the heating or cooling system18. In an embodiment, as shown with reference toFIG. 2, a fan or blower29may also be fluidly coupled to the fresh air intake duct to either induce air intake from an outdoor air space24or control the air flow rate entering the ERV2from the outdoor air space24.

Referring back toFIGS. 1-2, a filter element27is coupled to duct connection6in order to filter out any dust, debris, pollutants, or the like from the outside air stream8. Additionally, in an embodiment, a filter element28is coupled to a return port20to filter an exhaust air stream12that 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 element28, may be coupled to supply port22near or attached to the face of the heat exchanger14in order to filter the outside air stream8. In operation, an outside air stream8from, for example, an outdoor air space24enters the ERV2through duct6while stale conditioned air from an interior conditioned air space is received by ERV2and exhausted as an exhaust air stream12through the exhaust air duct10. Dampers25,26control the air flow rate entering or exiting the ERV2or, alternatively, Dampers25,26may be closed to bypass the ERV2. The outside air stream8circulates through the heat exchange device14where energy exchange takes place within the heat exchange device14. The extracted energy is transferred to the outside air stream8and it enters the heating and cooling system18as a fresh air stream through the supply port22.

In an embodiment, as shown inFIGS. 1-2, the ERV2may be electrically wired directly, via a two-wire line, to the heating and cooling system18in order to energize ERV2. The direct wiring eliminates need for providing an additional energizing power supply for energizing electrical components of the ERV2. 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 system18. The controller (not shown) controls operation of the ERV2while 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 ERV2while the furnace/fan coil air circulation blower is ON in order to provide a desired ventilation rate through the heating and cooling system18. In another example, the controller may operate the ERV2for a portion of each hour based on the desired ventilation rate and the air flow capacity of the ERV2. In an embodiment, the controller includes a microprocessor preprogrammed with software programs that is stored in nonvolatile memory for executing algorithms to provide the ERV2with a variety of operation modes and control sequences as indicated above.

In another embodiment, shown inFIGS. 1-2, the ERV2may be directly attached to, for example, an air circulation blower compartment of a furnace/fan coil of the heating and cooling system18through bolts, screws, or the like. But, in another non-limiting embodiment, the ERV2may be attached to a return air duct of an air handler without departing from the scope of the invention. In an embodiment, the ERV2may 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 system18may include fans (e.g., blowers, air handlers, and the like) to communicate air flow from an interior air space to the ERV2. 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 stream8enters the housing2through the duct connection6while stale conditioned air from the interior conditioned air space passes through the heat exchange device14. The heat exchange device14extracts energy from the stale conditioned air and exhausts the stale conditioned air as an exhaust air stream12from the ERV2. The outside air stream8circulates through the heat exchange device14where energy is transferred to the outside air steam8within the heat exchange device14. The outside air stream8receives the extracted energy and enters the heating and cooling system18as a fresh air stream through the supply port22. Further, stale conditioned air12is extracted from, in one non-limiting example, a return air duct that is directly connected to a conditioned air space. The stale conditioned air12, driven by fan16, enters the heat ERV2through return port20, circulates through the heat exchange device14, and exits the ERV2through duct connection10.

FIG. 3illustrates an elevation view of an ERV2that is connected to a heating and cooling system18according to an embodiment of the invention. In an embodiment, the ERV2is shown as part of a heating and cooling system18that may be directly attached to a furnace/fan coil30, which eliminates additional ducts to couple the ERV2to the duct system of the heating and cooling system18. The ERV2is in direct air flow communication with a return air duct36. Also, the attached ERV2directly receives power from a power supply wiring of the heating and cooling system18and is controlled by a controller associated with the system18. In another embodiment, the ERV2may be attached onto the system18and may be connected to ducts that are directly adjacent to the furnace/fan coil30. As shown, the ERV2may be sized to be located above an air cleaner such as, for example, a high-efficiency air purifier38while allowing for convenient access to the air cleaner during filter cleaning or maintenance. The ERV2is shown installed in a vertical orientation above the air purifier38with the housing being connected to a vertically oriented return air duct36and a vertically oriented furnace/fan coil30. But, in another embodiment, ERV2may be installed in a horizontal orientation in order to be coupled to a correspondingly horizontally oriented heating and cooling system18without departing from the scope of the invention. The air purifier38may be an Infinity Air Purifier manufactured by Carrier® that has a rated airflow of about 1600 or 2000 cubic feet/minute, but other air purifiers may be utilized without departing from the scope of the invention.

Also shown inFIG. 3, the ERV2includes a generally rectangular housing4that may be directly connected to a furnace/fan coil30through bolts, screws, or the like. The ERV2includes a fresh air intake duct6and an exhaust air duct connection10. The ERV2also includes a return port20and a supply port22. The return port20and supply port22are in direct communication with the return air duct36. The stale conditioned air stream42from an interior conditioned air space50enters the ERV2through return port20and exits the ERV2through duct connection10while an outside air stream8(shown inFIGS. 1-2) enters the ERV2through intake duct6and enters the return air duct36as a fresh air stream46through supply port22. The energy from the stale conditioned air steam42is extracted by the heat exchange device14(shown inFIGS. 1-2) inside ERV2and transferred to the fresh air stream46prior to its supply to the return air duct36. Further, the fresh air stream46mixes with the stale conditioned air stream42in the return air duct36. Also, the air purifier38receives the mixed air stream from the return air duct36and filters it as a filtered air stream48for communication to the furnace/fan coil30. In another embodiment, an air filter element (not shown) may be provided in lieu of the air purifier38in order to filter the stale conditioned air stream42. The furnace/fan coil30includes a circulation air blower compartment32having a circulating air blower33and an evaporator coil compartment34that includes an evaporator (not shown). The circulating air blower33recirculates the filtered air stream48from the compartment32through the evaporator coil compartment34and enters the supply duct40as conditioned filtered air44for conditioning the interior conditioned air space50. It is to be appreciated that the ERV2mounts directly to the furnace/fan coil30in order to exhaust stale conditioned air42from return air duct36while overcoming the negative static pressure in the return air duct36.

FIG. 4illustrates an elevation view of an ERV2that is in direct air flow communication with a furnace/fan coil30of system18according to another embodiment of the invention. As shown, the ERV2is sized to be directly connected to a circulation air blower compartment32of furnace/fan coil30and receives an air flow from the compartment32for energy recovery and recirculation to the interior conditioned air space50. The ERV2includes a fresh air intake duct6and an exhaust air duct10. The ERV2also includes a return port20and a supply port22that are in direct communication with the circulation air blower compartment32. The ERV2is shown installed in a vertical orientation directly coupled to furnace/fan coil30, which is also vertically oriented. But, in another embodiment, ERV2may be installed in a horizontal orientation in order to be coupled to a corresponding horizontally oriented heating and cooling system18without departing from the scope of the invention. A stale conditioned air stream42from an interior conditioned air space50enters system18through the return air duct36. In an embodiment, an air cleaner such as, for example, an air purifier38is provided to filter the stale conditioned air stream42and communicate a filtered air stream52to the negative pressure chamber of circulation air blower compartment32. In another embodiment, an air filter element (not shown) may be provided in lieu of the air purifier38in order to filter the stale conditioned air stream42. The filtered air stream52enters the ERV2through return port20whereby energy is extracted by the heat exchange device14(shown inFIGS. 1-2) prior to exiting the ERV2to the outdoor air space via duct10. This extracted energy is transferred to an outside air stream8(shown inFIGS. 1-2) that enters the ERV2through intake duct6. The outside air stream8(shown inFIGS. 1-2) is further communicated to the compartment32as a fresh air stream46through supply port22. The fresh air stream46mixes with the filtered air stream52in the compartment32. The circulation air blower33creates a positive pressure in a furnace/fan coil compartment35. The positive pressure overcomes the negative pressure in the circulation air blower compartment32and forces the mixed air from compartment32through the evaporator coil compartment34for heat-exchange within the evaporator coil compartment34. The mixed air is forced out of evaporator coil compartment34and through the air supply duct40as conditioned filtered air48in order to condition the interior conditioned air space50. It is to be appreciated that the ERV2mounts directly to the furnace/fan coil30in order to exhaust filtered air stream52from air blower compartment32while overcoming the negative static pressure in the blower air compartment32.

FIGS. 5-6illustrate a view of an air duct assembly60according to an embodiment of the invention. In a non-limiting example shown inFIGS. 5-6, the air duct assembly60may be coupled to ERV2for circulating fresh air from an outdoor air space61while recovering energy from stale conditioned air. But, in other embodiments, the air duct assembly60may be used with other types of energy recovery ventilators or may be also used without the ERV2. In order to show the interior configuration of the air duct assembly60in combination with the exemplary ERV2ofFIGS. 5-6, the exterior walls of the chamber70have been shown as if they are transparent. As shown inFIGS. 5-6, air duct assembly60includes an exhaust air duct62that is configured to reside within a fresh air intake air duct68. Also shown inFIG. 6, the air duct assembly60includes an insulation layer78that encapsulates the fresh air intake air duct68and insulates the assembly60.

Referring toFIG. 5, the exhaust air duct62is generally cylindrical in shape and extends from an outdoor air space61, through exterior wall64, and terminates into a duct fan66. Also, fresh air intake air duct68extends from the outdoor air space61, through exterior wall64, to a duct fan76within an air circulation chamber70. The fresh air intake air duct68, in one embodiment, is coupled to a filter element80in order to filter out any dust, debris, pollutants, or the like from an outside air stream8. The exhaust air duct62resides within a longitudinal cavity of the fresh air intake air duct68and is separated from the air stream that flows through the longitudinal cavity of fresh air intake air duct68. Further, the longitudinal cavity of the fresh air intake air duct68extends from the outdoor air space61to the interior cavity74, thereby forming a continuous opening from the outdoor air space61to the cavity74. Also, a concentric duct connection72couples the duct assembly60to each of the ducts62,68and prevents air leakage from the interior cavity74to the air space outside the ERV2. In operation, the air duct fan76draws an outside air stream8from, in an example, the outdoor air space61through the longitudinal cavity of fresh air intake air duct68and into the ERV2while stale conditioned air12from an interior conditioned air space50(shown inFIG. 3) is forced out by fan66and exhausted as an exhaust air stream12through exhaust air duct62.

FIG. 7depicts an ERV100having modular components to facilitate installation, service and maintenance of the ERV100. ERV100includes an insulated frame module102. Frame module102contains the heat exchange device14, filter28, fresh air supply and stale air exhaust openings with attendant seals. An insulated access door110may be mounted to either the front or back of the frame module102. Heat exchange device14may be slidably mounted to frame module102. In this manner, the heat exchange device14can be drawn out through access door110to allow for cleaning/service of the heat exchange device14.

A fan module104is removably mounted on top of frame module102by mechanical devices such as clamps, clips, etc. Fan module104includes a fan106for drawing outside air into the ERV100. Fan module104also includes damper26to control flow of outside air into the ERV100. Fan module104includes a fan108for expelling exhaust air out of the ERV100. Fan module104also includes damper25to control flow of exhaust air out of the ERV100. Fan module104also includes a controller105, where an electrical connection from the heating/cooling system is made. Controller105controls fans106,108and dampers25and26. Supply port22and return port20may be positioned on either the left or right side of frame module102.

ERV100has a narrow profile and can easily fit in tight installation spaces while still allowing for convenient filter and maintenance access due to its modular construction. The modular construction provides ease of installation and service. The insulated frame module102can easily be reconfigured for supply and return air path openings on the right or left side of the frame module102. The fan module104on top of frame module102allows for quick disassembly of the fan module104and controller105from the front of the ERV100after simply unlatching the access door110. The access door110may be formed in two pieces, one section to cover the fan module104with controller105and another section to cover the frame module102. To access either the fan module104or the frame module102, only one section of access door110needs to be opened. Dampers25and26can also easily be removed from the fan module104if desired. Heat exchanger core14may be slid out through access door110so the heat exchanger core14can be cleaned and serviced.

The technical effects and benefits of embodiments relate to an ERV for use with a heating or cooling system and include a fresh air intake duct and an exhaust air duct. An outside air stream enters the ERV through air intake duct while stale conditioned air from an interior conditioned air space is exhausted through an exhaust air duct. The ERV also includes a heat exchange device for recovering energy from the stale conditioned air. In an embodiment, the ERV may be electrically wired directly, via a two-wire line, to the heating and cooling system in order to energize the ERV. Also, the ERV may be connected to a furnace/fan coil controller of the heating and cooling system in order to control operation of the ERV without utilizing an additional dedicated controller for ERV control and operation.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. While the description of the present invention has been presented for purposes of illustration and description, it is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications, variations, alterations, substitutions, or equivalent arrangement not hereto described will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. Additionally, while the various embodiment 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.