The company has just installed several panels of solar water heating on
the factory’s roof, a thermal accumulation tank, a pumping system and
an electric panel for command and control.

The system automation uses technology supplied by Siemens Brazil
(www.siemens.com.br) with a microprogrammable logic controller, Simatic
S7-200, TP177 Micro human-machine interface, and analog and digital
expanded input/output. “It is an intelligent system that analyzes the
available temperature in the plates and, when it is enough, activates a
circulation pump that forces the passage of the water by the solar
collectors, and transfers it to the accumulation tank, forming a closed
circuit,” says Andre Petroff, Siemens Brazil Simatic Manager.

When the temperature in the tank is above a certain value, the pumps
that take hot water for the company’s cure ovens are turned off. After
that, the oil or gas heaters are turned off; the pneumatic valves are
actuated, stopping the flow of hot water, then the pumps are turned on
again. In this way, the system uses the hot water from the accumulation
tank. When the water temperature in the accumulation tank falls below a
certain value, the process is reversed and the system uses hot water
produced by the oil and gas heaters again.

“It is a system that allows better efficiency and cost reduction,
because the whole process is controlled by the automation system,
without need of intervention by operators,” notes Petroff.  “The values
of the heaters’ temperature, the accumulation tank, and so on, are
controlled by the PLC. The TP177 Micro screens supply an interface for
easy operation and monitoring. And the alarms are activated and
signaled when some anomaly happens.”

Sílvia Pereira , silviapereira@uol.com.br, is a freelance journalist based in Brazil.

Siemens Brazil
www.siemens.com.br

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