Air conditioning with recovery wheel, passive dehumidification wheel, cooling coil, and secondary direct-expansion circuit

Abstract

Air conditioning units, systems, and methods that control temperature and humidity within a space in a building, for example, using a recovery wheel, a desiccant-based or passive dehumidification wheel, a primary cooling coil; and a secondary direct-expansion refrigeration circuit that includes a secondary circuit compressor, a secondary circuit evaporator coil, and a secondary circuit condenser coil. In various embodiments, the system forms a supply airstream that passes outdoor air first through the recovery wheel, then through the primary cooling coil, then through the secondary circuit evaporator coil, then through the dehumidification wheel, and then to the space. Further, in many embodiments, the system forms an exhaust airstream that passes return air from the space first through the secondary circuit condenser coil, then through the dehumidification wheel, and then through the recovery wheel. In some embodiments, various quantities of heat and moisture are transferred between the two airstreams.