To reduce the depth of the indoor heat exchanger in room air-conditioners, we studied fin and tube heat exchangers, and found that we could make the heat transfer coefficient of fins 30% higher than of conventional fins by reducing louver width and fin pitch.
We also improved water drainage on the surface of the fins by adopting accordion-type offset-fin heat exchangers.
We found that the material cost of a heat exchanger was minimized when the heat exchanger had a tube 7 mm in diameter, and we could increase the heat transter coefficient of the refrigerant side by developing a new grooved tube 7 mm in diameter.
We succeeded in making the heat exchanger 40% thinner than conventional types.
