This invention is an air-cooled oblique-tube heat exchanger with plain fins. This invention offers greatly reduced air-side pressure drop by 14.4% for 1-3 m/s and higher heat transfer by 13.3% at the same fan power, as compared to commercial 1-row circular-tube condenser coils with corrugated fins. The advantages were derived from the slender shape of oblique tubes causing minimal resistance to the passage of air and much reduced wake zone resulting higher temperature gradients and greater heat transfer behind the oblique tubes. An integration of a middle rib in the tube strengthens its rigidity up to 50 bar, thus allowing potential wide adoption for water to refrigerant-based applications. Controlled atmospheric brazing can be used to braze oblique tubes, fins, headers, baffles and fluid ports in one process and to improve the joining quality between the fins and the oblique tubes.
The invention consists of heat exchanger core (i.e. oblique-shaped tubes and plain fins), headers with baffles for refrigerant flow distribution, brackets for supporting the coil structure to a wind tunnel or other structures based on customer requirement, and finally fluid ports for an refrigerant inlet and outlet. After a refrigerant flows into the inlet with high temperature, the locations of baffles influence the flow distribution. While the refrigerant is air-cooled, the inlet air temperature increases during heat exchange process. The refrigerant exists with lower temperature and the outlet air attains higher temperature as compared to their inlet ones.
The applications of this invention will be in residential and building air conditioning (AC) systems for AC outdoor units and air handing units as well as in cooling systems for data centers.
Improved heat transfer capacity
Reduced air-side pressure drop