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.

A fresh air conditioning system includes a first cooling device having a first cooling end and a first heating end; a dehumidifying rotary defining a first section and a second section. An airflow switching device directs a fresh airflow toward the first cooling end or the first heating end, and then flows to the first section. A return airflow passes through a first heat exchanger, and conducts heat exchange with the other end of the first cooling device, and then flows to the second section. Or switching opposite ends of the first cooling device to selectively cool or heat, the fresh airflow conducts heat exchange with one end of the first cooling device, and then flows to the first section. The return airflow conducts heat exchange with the other end of the cooling device and then flows to the second section.

A heating, ventilation, and/or air conditioning (HVAC) unit includes an energy recovery wheel, a first exhaust fan configured to draw a first air flow across the energy recovery wheel and discharge the first air flow from the HVAC unit, a second exhaust fan configured to draw a second air flow across the energy recovery wheel and discharge the second air flow from the HVAC unit, and a controller configured to operate the first exhaust fan and the second exhaust fan in an economizer mode and configured to operate the first exhaust fan and suspend operation of the second exhaust fan in an energy recovery mode.

An air-conditioning management apparatus includes: a storage unit that stores a schedule including a set time and a set temperature; a communication processing unit that communicates with the air-conditioning apparatus and receives operation status information including a heat medium temperature; and a controller that performs a schedule control to control the air-conditioning apparatus according to the schedule. The schedule control includes an optimal start-up control to control the air-conditioning apparatus such that an indoor space temperature reaches the set temperature at the set time, by starting an operation of the air-conditioning apparatus before the set time. The controller performs a preheating control or a precooling control to control the heat source unit such that before the optimal start-up control is started, the heat medium temperature included in the operation status information obtained from the air-conditioning apparatus falls within a target range including a previously set target heat medium temperature.

A heat exchanger for heat exchange between at least two fluids includes a plurality of heat exchange elements each having at least one fluid-guiding path for conducting at least one of the fluids through. The heat exchanger has a cylindrical shape or substantially cylindrical shape with a cylinder axis around which the heat exchange elements are adjacently arranged. At lease a region of each of the heat exchange elements forms an outline structure at least substantially like one of a triangular cylinder, a trapezoidal cylinder, a circle-sector cylinder, and an annulus-sector cylinder. As a result of adjacent arrangement of the heat exchange elements, the heat exchanger or at least a region of the heat exchanger has an outline structure at least substantially like one of a polygonal cylinder, a polygonal hollow cylinder, a circular cylinder, and annular cylinder. The cylindrical shape of the heat exchanger may alternatively be a cone frustum. The heat exchanger may be incorporated into an air device.

An air handling system is disclosed that includes an integral chilled water refrigeration system. The air handling system additionally includes a first coil section that provides cooling and a second coil section that provides heating. The second coil section and associated terminal units are in fluid communication with the first refrigeration system.

An improved HVAC system and method for simultaneously controlling the temperature and humidity of an indoor space while providing high quantities of outdoor air is described herein. The HVAC system of the present invention utilizes a heating source positioned in the supply passageway between an energy recovery wheel and a dehumidification wheel in order to control the temperature and humidity of air supplied to the indoor space while preventing frost build-up on the energy recover wheel. By positioning a heating source between the energy recovery wheel and a dehumidification wheel, the system is able to prevent frost accumulation on the energy recovery wheel during winter operation while also increasing the relative humidity of the supply air.

A dedicated outdoor air system and method that is capable of operating over a broader spectrum of conditions. The HVAC system of the present invention utilizes a heating means positioned within the return air passageway in order to optimize the regeneration of the desiccant wheel and energy recovery device. By positioning a heating means upstream of the regeneration side of the desiccant wheel, the system is capable of providing supply air having low dew points to the enclosed space while still providing improved energy efficiency over conventional HVAC systems.

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 air handler includes a housing with a heat exchanger core. The housing includes a faceplate, a roof panel, a base panel, a first side panel, and a second side panel. A first tunnel and a second tunnel are connected to the housing at the faceplate. A septum protrudes from the faceplate and connects the core at a front edge. The air handler further includes a first recirculation path and a second recirculation path inside the housing. The first and second recirculation paths are defined by the septum, the housing, and the core. The first and second recirculation paths are configured to direct a portion of airflow from the first tunnel to the second tunnel. The air handler further includes a first damper and a second damper disposed on the faceplate and configured to obstruct the first recirculation path and the second recirculation path respectively.