Abstract: A system and method for determining “real time” air leakage from a duct involves an airflow meter for taking airflow measurements at the inlet and at the outlet of the duct. Also included is a base fan that operates in three different modes to simultaneously vary an enclosure pressure at the inlet and outlet. This is done while a duct fan, inside the duct, is operated to continuously move air through the duct. A comparison of airflow measurements at the inlet, or at the outlet, under the three base fan operational modes will respectively identify whether leaks are present in the duct, upstream or downstream from the duct fan.

Abstract: An apparatus and method for noninvasively diagnosing a closed air refrigeration system includes a sensing unit which can be selectively placed over the evaporator inlet duct and the evaporator outlet duct to respectively measure the evaporator inlet enthalpy and the evaporator outlet enthalpy. Using both of these enthalpies, a computer calculates a sensible heat ratio for the evaporator which is useable to diagnose the system. Similarly, the sensing unit can be selectively placed over the condenser intake and condenser exhaust to measure the condenser intake enthalpy and the condenser exhaust enthalpy. Using these enthalpies, the computer calculates a sensible heat ratio for the condenser which is useable to further diagnose the system. Further, superheat and subcool set points can be calculated and compared with rated set points to evaluate the system. In an alternate embodiment, separate sensing units can be used simultaneously to measure the various enthalpies.

Abstract: An air sampling system includes a chamber that is formed with an exhaust port and a plurality of intake ports. A plurality of air collector arms are each attached in fluid communication with a respective intake port of the chamber. Further, each collector arm is formed with an inlet slot and an air channel which establishes fluid communications between the inlet slot and the respective chamber intake port. All of the collector arms extend outwardly from the chamber so that their respective inlet slots lie in a first plane. Relative to the inlet slots, the exhaust port of the chamber lies in a second plane that is substantially parallel to the first plane. Accordingly, a portion of the air that passes through the first plane toward the second plane, enters the inlet slots of the collector arms and is diverted into the chamber. In the chamber the diverted air is redirected out the exhaust port.