Finned Heater Performance: Fin Pitch Affects Heat Transfer and Airflow

Shengzhou Jinwei Electric Heating Appliance Co., Ltd. has published a technical analysis detailing the air-side performance characteristics of finned heaters. The study specifically examines how the spacing between the fins, known as fin pitch, impacts the heat transfer coefficient.

The company compares the effects of two fin pitches, 3 mm and 5 mm, on air-side performance. The analysis covers the calculation of the heat transfer coefficient, determination of fin efficiency, pressure drop, its effect on fan power selection, and application suitability for each pitch. The calculations reference industry standards, including the ASHRAE Handbook Fundamentals.

Results indicate that the 3 mm fin pitch consistently provides a 25–55% higher heat transfer coefficient compared to the 5 mm pitch at the same air velocity. This advantage increases with air velocity, as the denser finning enhances surface area and improves convective heat transfer.

The analysis also delves into calculation methodologies, such as using Reynolds and Nusselt numbers to determine the heat transfer coefficient. It further investigates fin efficiency, which quantifies the fins' ability to transfer heat from the source to the surrounding air. However, tighter fin spacing (3 mm) may result in higher pressure drop and a greater risk of dust accumulation compared to wider spacing (5 mm).