An experimental study of heat exchanger performance has been conducted utilizing a basic cross-flow heat exchanger configuration. Six different cross-flow, finned-tube heat exchanger flow configurations were tested in a specially designed wind tunnel system to investigate the importance of the Temperature Difference Uniformity on the effectiveness of heat exchanger performance. The Temperature Difference Field (TDF) and the Temperature Difference Uniformity Factor, {Phi}, were employed as design factors to characterize and evaluate heat exchanger thermal performance. A base heat exchanger configuration was established, and then five modifications on the base configuration were made in a systematic study to enhance the performance. The fluids were air on the outside, and hot water inside the tubes. The basic configurations included either 28 or 56 tubes in the bank. The results of the experiments have clearly demonstrated the importance of flow distribution and how it can be used to control the Temperature Difference Field; which, as a design parameter, is an important component of heat exchanger performance optimization. Heat exchanger effectiveness for the best flow distribution was found to increase by 4.3% over that of the conventional flow distribution with no associated increase in pressure drop. This promotes a new path for them tomore » increase heat exchanger heat transfer effectiveness. Comments on further possible performance enhancement strategies are presented.« less