A hybrid air conditioning apparatus includes a first air conditioning device and a second air conditioning device. The first air conditioning device is a cooling and heating air conditioner, and the second air conditioning device communicates with the first air conditioning device. Air modulated by the second air conditioning device is sent to the first air conditioning device for cooling and heating air adjustment. Accordingly, the air discharged from the first air conditioning device has enhanced quality and all kinds of properties in the air are provided uniformly.

An energy recovery ventilator cabinet containing a plurality of enthalpy wheels. The enthalpy wheels are substantially perpendicular to a stream of forced air, allowing the air to pass through the wheels. The enthalpy wheels are also disposed such that portions overlap, allowing multiple enthalpy wheels to be disposed in a smaller space than if the enthalpy wheels were placed side by side. This arrangement has led to energy recovery effectiveness similar to that obtained by a larger, single enthalpy wheel, but has the advantage of using less space.

An air conditioner controlling method includes: deciding on a supply-air temperature Ts and a return-air temperature Tr as specified design values; deciding that the total heat-exchange efficiency η is zero; selecting two or more stepped levels of the outdoor-air volume percentage α; deriving a linear function which expresses a relation between an outdoor-air temperature To and a mixed-air temperature Tm for each level of the outdoor-air volume percentage α by using the return-air temperature Tr and the total heat-exchange efficiency η; and deciding on the range where the mixed-air temperature Tm is lower than the supply-air temperature Ts for each of the linear functions and the range where the mixed-air temperature Tm in each linear function comes closest to the supply-air temperature Ts as compared with the mixed-air temperatures Tm in the other linear functions.

An air handling unit, particularly for data center cooling, operates to cool a flow of return air from a conditioned space using a flow of ambient air. The return air is recirculated to the conditioned space as supply air. The flow of ambient air can be adiabatically cooled to a lower temperature to provide additional cooling. A flow of makeup air can be joined with the cooled return air to form the supply air, and can be sourced from the ambient environment directly or from the heated flow of ambient air.

A rooftop HVAC unit includes a cabinet, an energy recovery wheel, dampers, and a controller. The energy recovery wheel is configured to be mounted within the cabinet. The energy recovery wheel is configured to transfer heat between an outdoor air stream and a return air stream when in an operational mode, and is further configured not to transfer heat between the outdoor air stream and the return air stream when in a bypass mode. The dampers can direct the outdoor air stream and return air stream through the rooftop HVAC unit, either through the energy recovery wheel or around the energy recovery wheel. The controller is configured to adjust the dampers based on a selection between the operational mode and bypass mode of the energy recovery wheel.

A building ventilator to provide a supply of air into a building comprises an external inlet port and a separate external outlet port and an internal inlet port and a separate internal outlet port to allow respective airstreams to flow into and out of the ventilator respectively at an exterior and at an interior of the building; a heat exchanger mounted in the flow paths between the external and internal inlet and outlet ports. The ventilator is configured to drive an airflow from the external inlet port through the heat exchanger and out of the ventilator via the internal outlet port; and to drive an airflow from the internal inlet port through the heat exchanger and out of the ventilator via the external outlet port. The ventilator comprises a heating element mounted in the air flow path between the external inlet port and the heat exchanger.

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 integrated ventilation unit configured to provide ventilation and conditioned air to an indoor space may include a heat pump system, an energy recovery device and a control unit. The heat pump system may include a first coil located at a supply air side of the ventilation unit, a second coil located at an exhaust air side of the ventilation unit, and a compressor. The energy recovery device may be configured to transfer heat between a return air stream and a supply air stream and the control unit may be configured to control operation of the heat pump system and the energy recovery device.

A system for use with a conditioned space. The system includes an energy transfer device and at least one element. The energy transfer device transfers heat from a hotter air flow and a cooler air flow. The energy transfer device prevents the hotter air flow from mixing with the cooler air flow. A supply one of the hotter and cooler air flows enters into the conditioned space and a return one of the hotter and cooler air flows exits from the conditioned space. The element(s) heat or cool the supply air flow before the supply air flow reaches the conditioned space.

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.