RP-122 -- Heat Exchanger Dynamics of a Discharge Control System PDF

An important part of the investigation of the dynamics of a heat exchanger discharge temperature control system is the investigation of the dynamics of the heat exchanger alone. This study considers, through analysis and experiment, the dynamic behavior of a tube and plate-fin, serpentine, commercial, water-to-air heat exchanger. The behavior of particular interest is the dynamic response of the discharge air temperature to changes in the hot water flow rate. This is compatible with the common configuration of the control system whereby a flow modulating water valve driven by a controller with a temperature sensor in the duct downstream of the hot water coil is used to control the air discharge temperature.

To design or select the control components of the entire system, an accurate but simple dynamic model of the heat exchanger is desired.