Development of theory for near-optimized selection of machinery for production of convective dryer-air in industrial applications

From Elsayed and Boucher, in their text titled Analysis and Control of Production Systems: "It has been shown that the major component of productivity improvement in U.S. industry is directly traceable to the employment of new machine (production) technology." Many industrial settings require drying as a part of the production process and as such, require the selection of equipment to produce the dryer-air to be used in the drying component of the manufacturing process. The difficulty in optimizing such a selection is that the primary cash flows of the dryer-air generator is its first cost and the cost of fuel use, and both are dependent and interrelated to the type of generator selected and its selected sub-components. Also, the sub-components for each type must work together to produce the temperature, relative humidity and air flow of the production dryer-air requirement, and many components might be mixed in different ways to meet the dryer requirement.; This research develops a model for the selection of dryer-air generation machinery using the equivalent uniform cost evaluation method. The example provided is a continuous lumber dryer. Four generic machine types for the generation of dryer-air are considered: gas fired, gas fired desiccant, heat pump, and desiccant heat pump or Cromer cycle. As part of this model, new theory for the component sizing of a parallel flat tubing evaporator deep (microchannel) for heat pump dryers and new theory for component sizing of desiccant wheels used in Cromer cycle desiccant assisted drying were experimentally developed. This theory allows for the sizing of components necessary for engineering economic analysis. Because component fractional sizes we not available from manufacturers, near-optimization is achieved by the selection of the next largest available size.; The methods previously available to evaluate industrial drying considered the dryer and the dryer-air generator as a single entity. This new model, incorporating component sizing of dryer-air generator alternatives, with developed microchannel and desiccant wheel theory based on isotherms, provides, a "cash flow" solution methodology for this machinery selection problem and the potential to significantly reduce the per unit drying cost.