Researchers explore flattened tubes for heat exchangers

Researchers at the University of Illinois have been investigating flattened tubes for heat exchangers to see how they perform during different environmental conditions.
Replacing traditional round tube heat exchangers with flattened tubes could present a number of benefits for air conditioning systems. The geometry of a flattened tube compared with the traditional round tube heat exchanger makes it possible to have an improved heat transfer thermal performance. The flattened tube also reduces the refrigerant charge and has other efficiencies related to the coils.
A newly released report on the University of Illinois research was published by the Air-Conditioning and Refrigeration Technology Institute (ARTI) in the U.S.
In the report, the University of Illinois researchers provide analysis, modeling, and an interpretation of air-side, thermal-hydraulic performance for flattened tube heat exchangers under wet and frosted surface conditions. They make design recommendations to help improve the performance of plain, wavy, strip and louvered fins for flattened tube heat exchangers. They conduct a full assessment of the air-side thermal-hydraulic performance of flattened, round, and finned heat exchangers. In addition, the researchers developed a new method to provide data on the retention and drainage of water from the air-side surface of flattened tube heat exchangers under a number of operating conditions.
“Flattened tube heat exchangers have received much attention as a possible replacement to traditional round tubes, but until now little research has been done on the thermal-hydraulic performance of flattened tubes under wet, dry and frosted conditions,” said Elizabeth Jones, a project manager with ARTI, which funded the project. “This research report addresses the fundamental science needed to allow the air conditioning industry to engineer products using this technology.”
To read the final report, “An Assessment of the State-of-the-Art and Potential Design Improvements, for Flat-tube Heat Exchangers in Air-Conditioning and Refrigeration Applications,” go to http://www.arti-research.org/research/completed/finalreports/20021-final.pdf.