433 results about "Ventilation mode" patented technology

An energy-reducing method and apparatus for retrofitting a constant volume HVAC system, with or without an economizer, that provides heating, cooling, and ventilation to occupants within a building space. The present invention includes the introduction of a programmable logic controller and variable frequency drive (VFD) that takes control of the existing fan, heating, cooling, and optional economizer operation. The controller is programmed for the reduction of fan speed in the heating and cooling modes. The reduction of the fan speed in the ventilation mode when the 100% operation is not needed saves significant energy of the existing constant volume HVAC system where the fan motor is designed to run 100% of the time. The fan speed may be further reduced upon a reduction in sensed occupancy levels of the space, such as with a CO2 sensor. Additionally, the fan speed may be reduced in the heating and / or cooling mode to further reduce energy consumption. The controller may also be programmed and equipped with sensors to allow simultaneous mechanical compressor cooling and economizer free cooling operation, for the operation of the economizer in response to the monitoring of outside air and return air to determine the preferred source for cooling operations, to keep the outside air damper closed during the unoccupied heating modes such as morning warm-up, and / or to provide fault detection. The retrofit method and apparatus may be employed in a stand-alone or networked version.

A method performed by a zone controller for a zone of a building for improving energy efficiency in a heating, ventilation, and air conditioning (HVAC) system is provided. The method includes operating in a ventilation mode. A temperature of the zone and outside air conditions for the building are monitored. A determination is made regarding whether to switch from the ventilation mode to an economizing mode based on a first set point for the temperature of the zone and based on the outside air conditions. The first set point is determined based on a second set point for the temperature that is different from the first set point. A determination is made regarding whether to activate the HVAC system based on the second set point.

A clean room unit which is equipped with a work room and a clean bench unit can be independently installed inside a building, can generate an air shower in the work room, and can realize miniaturization and cost reduction. The clean room has a work room, a clean bench unit which has a work opening and has the work opening installed to look onto the work room, an air conditioning system which can perform purification and pressure control of air inside the work room and the clean bench unit and can generate an air shower in the work room, and a control unit. The air conditioning system is controlled by the control unit to switch exclusively between the air shower mode, the ventilation mode, the positively-pressurized work mode, and the negatively-pressurized work mode.