Effectiveness and pressure drop characteristics of various types of air-to-air energy recovery systems.

The performance of an HVAC system's air-to-air energy recovery exchanger is defined primarily by the exchanger's effectiveness and pressure drop. The effectiveness is dependent on several parameters such as the supply and exhaust mass flow rates and the energy transfer characteristics of the device. Because of this combination, performance data must be established for each individual type of device. Presents the results of applying the methodology of ASHRAE Standard 84-78 in determining the performance of four types of devices: 1) coil energy recovery loop; 2)heat pipe heat exchanger; 3) fixed plate exchanger; and 4) the twin tower enthalpy recovery loop (open run-around) system.