Heat Pump Clothes Dryer Model Development

A heat pump clothes dryer (HPCD) is an innovative appliance that uses a vapor compression system to dry clothes. Air circulates in a closed cycle through the drum, so no vent is required. Condenser heat evaporates moisture out of the clothes, and the evaporator condenses the water out of the air stream. As a result, the HPCD can achieve 50% energy savings compared to a conventional electric resistance dryer. We developed a fundamentals-based, quasi-steady-state HPCD system model with detailed heat exchanger and compressor models. In a novel approach, we applied a heat and mass transfer effectiveness model to simulate the drying process of the clothes load. The system model is able to simulate the inherently transient HPCD drying process, to size components, and to reveal trends in key variables (e.g. compressor discharge temperature, cloth drying rate, etc.) The system model was calibrated using experimental data on a prototype HPCD. In the paper, the modeling method is introduced, and parametric studies show the influences of design parameters (compressor size, air flow circulation rate, and leakages) on system performance (including energy factor and drying time).