Experimental and Numerical Study of Heat Pipe Heat Exchanger with Individually Finned Heat Pipes

• Main Authors: Grzegorz Górecki, Marcin Łęcki, Artur Norbert Gutkowski, Dariusz Andrzejewski, Bartosz Warwas, Michał Kowalczyk, Artur Romaniak
• Format: Article
• Language: English
• Published: MDPI AG 2021-08-01
• Series: Energies
• Subjects: heat pipe heat exchanger; wickless heat pipe; heat transfer; individually finned tubes
• Online Access: https://www.mdpi.com/1996-1073/14/17/5317

The present study is devoted to the modeling, design, and experimental study of a heat pipe heat exchanger utilized as a recuperator in small air conditioning systems (airflow ≈ 300–500 m³/h), comprised of individually finned heat pipes. A thermal heat pipe heat exchanger model was developed, based on available correlations. Based on the previous experimental works of authors, refrigerant R404A was recognized as the best working fluid with a 20% heat pipe filling ratio. An engineering analysis of parametric calculations performed with the aid of the computational model concluded 20 rows of finned heat pipes in the staggered arrangement as a guarantee of stable heat exchanger effectiveness ≈ 60%. The optimization of the overall cost function by the “brute-force” method has backed up the choice of the best heat exchanger parameters. The 0.05 m traversal (finned pipes in contact with each other) and 0.062 m longitudinal distance were optimized to maximize effectiveness (up to 66%) and minimize pressure drop (less than 150 Pa). The designed heat exchanger was constructed and tested on the experimental rig. The experimental data yielded a good level of agreement with the model—relative difference within 10%.