Energy efficient air quality maintenance system and method

摘要

A heating, ventilation, and air conditioning (HVAC) system uses unvitiated secondary return air to control the amount of a contaminant, such as carbon dioxide, in a space to maintain an improved air quality throughout the area served by the system. Preferably a terminal box controls the CO2 level in the space served by the box by selectively drawing air representative of air in other rooms to lower the CO2 level in the space being served. This reduces cost because air which is provided from other rooms within the building will require less total system heating or cooling in order to maintain the occupied space at the desired air quality.