Dual duct variable volume air conditioning system

摘要

A dual duct variable volume air conditioning system has a first, cold duct for supplying cold air and a second, reset duct for supplying either hot air in a first mode of operation or cold air in a second mode of operation. A self-contained system regulator positions first and second valves in the first and second ducts in response to changes in room temperature. The regulator is effective to reverse the direction of response of the second valve to temperature in the second mode of operation from the direction of response of that valve to a similar temperature change in the first mode of operation so that the reset duct can be used as a hot duct with the system supplying warm or cold air on demand in the heating season (without mixing) and as a cold duct to double the cooling capacity of the system in the cooling season. The system includes an integrated sensor-actuator for each air flow duct having a diaphragm which both senses the flow velocity in the duct and positions the valve in the duct through a direct mechanical connection. The actuator moves the valve with changes in flow velocity using the pressures in the duct without a relay.