Departamento de Engenharia Mecânica, Universidade Federal do Paraná, Curitiba, PR, 81531-990, e-mail: jvargas@demec.ufpr.br

In this seminar, an alternative solution to reduce energy consumption in industrial refrigeration systems is proposed and introduced. For that, a typical industrial refrigeration system was conceived, built and modified in the laboratory, receiving a novel power law control system, which utilizes a frequency inverter. This way, it was possible to compare the operation and energy consumption of the system operating either with the new control system or with the traditional on-off control, quantifying realistically the obtained gains. In order to accomplish the proposed task, it was conceived and built in the laboratory, an experimental unit (Fig. 1) which consists of a cold chamber and of a vapor compression refrigeration unit, which portrays the actual operation of an industrial refrigeration system. The results obtained in this study are presented in a set of graphs that depict the experimental measurements performed in the two systems (Figs. 2-4). In this manner, the measured temperatures in several points of both systems are compared, and the energy consumption in kWh during the period of 24 hours of the tests performed. The main conclusions are: (a) the electrical energy consumption of the closed loop power law controlled system shows an energy economy of 35.24 % (Table 1), with respect to the traditional on-off system, for a test period of 24 h, under the same operating conditions, and (b) the variation of the chamber internal temperature is much smaller in the power law controlled system than in the on-off system.