Multi-objective optimization of the operation strategies for heat pump tumble dryers with different fabric types

The heat and mass transfers in a heat pump tumble dryer are significantly influenced by the fabric properties and operating factors, including the temperature, humidity, and volumetric airflow rate. In this study, optimal operating strategies for heat pump tumble dryers with various fabric types are developed in terms of the compressor frequency and fan rotational speed. The evaporation characteristics of each fabric type are measured under various operating conditions. A heat pump tumble dryer simulation model for each fabric type is developed by combining a heat pump model with a tumble drum model based on experimental correlations. Consequently, the optimal fan speed for each fabric type is determined at a specific compressor frequency. Increasing the compressor frequency leads to increased energy consumption, resulting in a trade-off between the Moisture Extraction Rate (MER) and Specific Moisture Extraction Rate (SMER). Moreover, the energy efficiency of the system is evaluated through the coefficient of performance. Additionally, Pareto-optimal solutions for each fabric type are determined using multi-objective optimization. Under the condition of maximum SMER, the MERs and SMERs increased by 7.4–9.4% and 3.1–4.5%, respectively, compared with those in the conventional energy-priority mode. Similarly, under the condition of maximum MER, the MERs and SMERs increased by 6.7–9.9% and 7.9–12.1%, respectively, compared with those in the conventional performance-priority mode.