To increase competitiveness, an alternative increasingly adopted by
organizations is the search for reduction of energy consumption in
production processes. This work presents a study of thermal and
electrical behavior of a set of finned-tube heat exchangers using water
to be cooled/forced ambient air installed with a water cooling system
by means of the plate heat exchanger using cooled water/ice water. The cooled
water circulating in this cooling unit exchanges heat with vegetable oil
in an oil/water plate heat exchanger in the primary process. The
objective of this study was to relate the operating conditions of the
cooling unit with the minimum total electrical power used in
ventilation, pumping and chiller, referring to the variable thermal
heating demand of the oil. In this study, the influence of the following
independent operational variables were evaluated: air flow rate, cooled
water flow rate, chilled water flow rate and magnitude of heating source
power. To define the cooling strategy, the temperature of the operation
water heated by the oil was limited to 90°C, to avoid boiling at
ambient pressure. The cooling strategy could be compared to the cooler
operating with its manipulated variables at constant values and at
full rate, by means of energy performance indicators. With this study it was
possible to suggest the best operating conditions of the cooling unit and its
respective performance indicators of reduced power consumption referred
to any heat demand of the primary process. Energy savings reached 50% in
the lowers imposed heating powers. It was concluded that the operating
conditions in the cooling unit should be changed to reach lower energy
expenditure under variable thermal demand.