Numerical Optimization of the Annual Cost of a Clothes Dryer

Optimization of the energy cost of clothes dryers saves on energy use without requiring additional installations. To optimize the cost of clothes dryers, a correlation has been developed for the evaporative mass flux produced in the drum. The correlation was used to determine the drying time and cost. An objective function for the drying cost was defined in terms of the total annual dryer costs for energy usage, material, and manufacturing. The objective function (Annual cost) was optimized for two cases relative to 8-10 of the dryer parameters subject to various operating constraints using the direct search and the variable metric methods. The optimization results indicate that there are optimum settings for the fan speed and the drum speed depending on the weight of the drying load and heater power. The results showed that the optimum lies at the highest drying load and the lowest (37.45% in Annual cost could be saved) or the highest value of heater power (19.7% in Annual cost and 52.6% in drying time could be saved), whichever satisfies the drying time constraint. The applications of the optimization results are discussed.