In a heat-stressed industry where process loads are very high and/or there are comparatively few workers or work stations, total area air conditioning is prohibitively expensive and wasteful of energy. In such situation, spot (area or localized) cooling systems may be used to provide environmental conditions proper for worker comfort, or stress avoidance, only in the immediate vicinity of the worker.

The optimization problem is to minimize the system’s energy requirement by determining the optimum jet size, cooling jet air velocity, and the temperature and humidity from a refrigerating system that provides the proper environment for workers within the permissible physiological strain. The problem is a nonlinear programming problem and is solved by a generalized reduced-gradient (GRG) method. In the case study, effects of outdoor weather conditions, factory air conditions, worker loading, and worker’s clothing on optimal system design and control are investigated.