SUMMARY

Drying is a ubiquitous process in a wide range of applications and industries, including residential and commercial clothes dryers, agriculture, chemical processing, and pharmaceutical industry. Clothes dryers have become widespread in North American households and commerce. More than 80% of the households in the US have a washer and dryer. Thermal drying of clothes is a very energy-intensive process coupled with the complexities of several transport phenomena (mass, momentum, and energy) occurring simultaneously, and their influence on material properties. Dryers reject ~ 60% of the total input energy as waste heat or losses. While system efficiency can be improved by optimizing system design and operational parameters, there is also a significant opportunity in harnessing the energy from the exhaust stream of the dryer and storing it for use in future drying cycles.
In this proposed work, a fundamental understanding of the heat and mass transfer processes in drying will be investigated with the goal of simultaneously reducing energy consumption and drying time. Transient thermodynamic, heat and mass transfer models will be developed and validated experimentally. The validated models will be used to optimize energy consumption and cycle time. Recirculation, waste heat recovery, thermal energy storage, and heat pumping will be investigated as a means to achieve these goals. Thermal storage will be used to store the heat released during a cycle for reuse in subsequent cycles. Sorbent beds and heat and mass exchangers will be used for heat pumping of the recovered and/or input energy. A commercial tumble dryer will be used to implement these changes and demonstrate the effects of these enhancements.