Abstract

An air circulation system is used to control the temperature in an area defined by a series of zones. The system has a hot deck and a cold deck, and a series of ducts each extending from the downstream side of the decks to a respective zone. A damper in each duct controls the amount of air entering the duct from each deck. The zone having the highest heat load and the zone having the lowest heat load are empirically determined, and a sensor is installed in each of those zones to monitor temperature. A temperature deviation in those zones from a temperature initially set into the system causes the duct dampers to those zones to adjust, and may also cause heat to be supplied or withdrawn from the decks. Each of the remaining zones normally has a temperature between those of the highest and lowest heat load zones. A thermostat and a backup sensor are installed in each of the remaining zones; a thermostat controls only the duct damper leading to the respective zone, and a backup sensor controls only heat supply or withdrawal from the decks. This system has a significant savings in energy cost over other multiple-zone systems, in which each zone has a thermostat controlling both the setting of the respective duct damper as well as the supply or withdrawal of heat from the decks.