Investigation of mechanical effects on heat pump evaporator to accelerate water drainage

Abstract

Condensation of water vapor in humid air and water drain process through evaporator fins are studied both experimentally and numerically at 23°C dry bulb temperature and 55% relative humidity. In the experimental campaign evaporator attached to heat pump unit is physically influenced with mechanical impact plate and actuator-induced vibrator separately so as to increase transient water drainage through evaporator fins. The amount of water collected inside the pot located underneath evaporator is compared for the heat pump unit with and without mechanical effects assessing effectiveness of the applied physical improvements. Whilst the amount of water collected per hour increases 13% by oscillator-induced vibrations, 18% is also achieved by mechanical impact plate. Furthermore, a specific attention is paid on the numerical modeling of impact generated with mechanical impact plate to foresee the applicability of the method for evaporators varying in terms of structural design parameters. Numerical studies reveal that the amount of drained water from plate fin heat exchanger increases up to 15% by the mechanical impact which is found to be in good agreement with.