Experimental evaluation of a heat exchanger for different configurations between internal and external flow

In the present work, the determination of the thermal effectiveness and temperature of the air at the outlet of a scale prototype of a heat exchanger immersed in flowing water was developed experimentally. This depended on the position of the working fluid (air) and of the heat exchanger positioning configuration. The tested positions were parallel flow, quasi-parallel oblique, counterflow, quasi-counterflow oblique, and crossflow. The temperature of the air at the outlet of the heat exchanger and the thermal effectiveness are essential to determine the most convenient operating position of these systems, especially those related to shallow geothermal energy. The thermohydraulic aspects of the heat exchanger presented were evaluated, by the Number of Transfer Units-Effectiveness (NTU-epsilon) method, under conditions of water flow in a natural channel and air flow induced by a blower, the system was built from commercial copper pipe and temperature sensors were placed in both the exchanger and the water to record temperature changes. The results of this study indicate that when the exchanger is positioned in the oblique quasi-counterflow position and the oblique quasi-parallel position, it exhibits the lowest air outlet temperatures and highest thermal effectiveness, which is relevant for building cooling applications.