A rooftop air conditioning unit includes a cabinet, an energy recovery wheel rotatably mounted within the cabinet, and a controller. The energy recovery wheel can transfer heat between an outdoor air stream and a return air stream when rotated into an operational position and will not transfer heat when rotated into a bypass position. The controller can select the operational position of the energy recovery wheel and an operational mode of the energy recovery wheel.

The disclosure relates to a heat transfer assembly for a rotary regenerative heat exchanger. The assembly includes a rotor arranged between at least two separated fluid flow passages passing flow axially through the rotor, where each flow passage is connected to a sector part of the rotor. The assembly further includes a plurality of channels in the rotor for flowing a fluid through the rotor, each of the channels is enclosed by heat transfer and heat accumulating surfaces in the rotor, and the heat transfer and heat accumulating surfaces of the channels are made in a material providing an average axial thermal conductivity less than 100 W/mK arranged to reduce the Longitudinal Heat Conductivity of the rotor.

An insulation retaining assembly for a high temperature rotary pre-heater having a cold-end rotor and a hot-end rotor includes a plurality of elongate retainer elements. Each of the retainer elements has a root end adapted to be held in fixed relationship to the cold-end rotor and a distal end proximate to the hot-end rotor. Portions of each of the plurality of retainer elements are adapted for circumferential movement.

A heat transfer sheet assembly for a rotary regenerative heat exchanger has first and second heat transfer sheet elements stacked one against the other with a first repeat of a first profile on one sheet element opposing a second repeat of a second profile on the other sheet element. The sheet elements are spaced apart by a plurality of wide-gauged parallel sheet spacing features of the first profile repeat RI of the second profile repeat to form a generally close sided elongate channel for gaseous flow therethrough. The second profile of repeat includes an elongate fifth sheet spacing feature in the form of a lobe contacting undulations of the adjacent first profile of repeat.

A seal assembly includes a leaf assembly and a supplemental leaf assembly. The leaf assembly includes a first leaf having a first base section. The first base section defines a first fastening area for securing the first leaf to a diaphragm of the preheater. The first leaf has a first elongate section extending away from the first base section and terminating at a first distal end thereof. The leaf assembly further includes a second leaf that engages a portion of the first leaf. The second leaf has a second base section. The second base section defines a second fastening area for securing the second leaf to the diaphragm. The second leaf has a second elongate section extending away from the second base section and terminating at a second distal end thereof. The supplemental leaf assembly is secured to the first leaf and slidingly engaging the second leaf.

A rotor for a high temperature rotary pre-heater includes a hub that has an exterior surface thereon. The rotor includes an annular rim positioned around and coaxially with the hub. The annular rim has an interior surface. A plurality of partitions extend between the hub and the annular rim. Each of the partitions is located in a predetermined circumferential position by one or more alignment features. The exterior surface, the interior surface and/or the partitions have one or more of the alignment features thereon.

Disclosed is a heat transfer assembly for a rotary regenerative preheater. The heat transfer assembly includes a plurality of heat transfer elements stacked in spaced relationship to each other in a manner such that each notch from a plurality of notches of one of the heat transfer element rests on respective flat sections from a plurality of flat sections of the adjacent heat transfer elements to configure a plurality of closed channels, each isolated from the other, wherein each of the channels has a configuration in a manner such that each of corrugation sections from a plurality of corrugation sections of one of the heat transfer elements faces respective undulation sections from a plurality of undulation sections of the adjacent heat transfer elements.

A basket for an air preheater includes two metallic frames each having two corner pieces and two connector pieces. For each frame, one of the connector pieces is secured to one end of each of the corner pieces and another of the connector pieces is secured to an opposite end of each of the corner pieces thereby forming a rectangular opening in each frame. The basket includes two heavy gauge metallic sheets that are secured to the corner pieces, thereby spacing the frames equally apart from and parallel to one another thereby forming a channel between two of the sheets.

An energy recovery wheel includes a frame positioned within a passage of a heating, ventilation, and/or air conditioning (HVAC) system. The frame is configured to rotate about an axis of the passage relative to the HVAC system and includes an opening that is configured to transmit an air flow. The energy recovery wheel also includes a heat transfer element coupled to the frame and positioned within the opening, where the heat transfer element is permeable and configured to transition between a closed orientation to occlude the opening and direct the air flow across the heat transfer element and an open orientation to substantially unblock the opening and mitigate interaction between the air flow and the heat transfer element.

A stack of heat transfer sheets includes one or more first sheet which includes a first undulating surface formed by first lobes that are parallel to each other and oriented at a first angle. The first sheets include a second undulating surface formed by second lobes that are parallel to each other and oriented at a second angle, different from the first angle. The first sheets include a third undulating surface formed by third lobes extending from one or more ends of the first sheet and terminating at an intermediate point between the end and an opposing end thereof. The third lobes are parallel to each other and parallel to the direction of flow through the stack. The stack includes one or more second sheets defining a plurality of sheet spacing features which engage a portion of the first sheet.