Effect of Inclination on the Performance of a Compact Brazed Plate Condenser and Evaporator

Abstract

This study experimentally quantified the change in heat transfer and pressure drop associated with tilting a compact brazed plate heat exchanger from the intended vertical position. Both clockwise and counterclockwise rotations within a plane perpendicular to the fittings were examined. A SWEP B15 × 36 was tested as an R-22 evaporator and condenser under fixed refrigerant state conditions suitable to high-efficiency water-source heat pumps. This study showed that a substantial performance penalty occurred when the evaporator was rotated past 30° from the vertical. The evaporator heat transfer in the horizontal position was 60-75% of the vertical value. For a rotation angle of 30°, the degraded heat transfer was within 5% of the vertical value. Rotation direction and entering refrigerant state had little effect on the performance of the evaporator for rotation angles less than 60”. Only when the evaporator was rotated to the horizontal position did rotation direction and refrigerant slate have much effect. At the horizontal position, a subcooled-entering refrigerant and a counterclockwise rotation both tended to lessen the evaporator heat transfer degradation. Rotation of the condenser to the horizontal position improved the overall heat transfer coefficient by approximately 17-30%. Rotation direction had a negligible effect on the performance of the condenser for angles less than 60°. Both the evaporator and condenser pressure drops were influenced by flow distribution changes as the heat exchangers were rotated.