Investigation of heat transfer and energy distribution inside dishwasher based on a coupled 3D-1D simulation method

Abstract

Improving energy efficiency of dishwasher products is not only critical for their market competitiveness, but also vital for reducing global carbon emission. To enhance their energy performance, previous studies developed models to simulate dishwashers' operating processes, but most investigations focused on simulating only a partial operating cycle, which was not sufficient for fully understanding the whole-cycle energy distribution. Besides, many simulations assumed constant heat transfer coefficient between tableware and washing fluid, leading to simulation inaccuracies. This research studied the heat transfer and energy distribution inside dishwasher by developing a conjugate 3D-1D simulation strategy, which modeled energy consumption based on dynamic HTC values and was validated by measured data. The simulated temperature and energy consumption results deviated from measurement by less than 0.5 °C and 35.7%, respectively, during a 300s heating process. Results also showed that 35.7% of consumed energy was absorbed by tableware as heat. This study not only established a novel simulation strategy that could calculate whole-cycle energy consumption and energy distributions in dishwashers with good accuracy, but also demonstrated dishwashers’ energy consumption could be reduced via design optimizations. By increasing insulation thickness from 20 mm to 40 mm alone, the total energy consumption was reduced by 8.4%.