NG Global

Solar Energy for building automation

This application is considered as a "world première" in solar energy control. It has been implemented for the new building of CNRS-IMP in France in March 2003. This building is clearly oriented "clean energy".

TBOX is used for the monitoring and control of UPS systems, powered by photovoltaic panels. Those UPS convert DC currents, coming from the solar panels, into AC currents. TBOX reads values from the various UPS, such as voltage, output current in DC from the photovoltaic panels and voltage, power and current in AC.

Sampling tables are logged at regular intervals. Total power is measured by pulsed inputs (one for each phase) on Digital Inputs of TBOX.

The embedded ASCII library permits to communicate with the proprietary protocol of the UPS. The TBOX CPU has to communicate with 5 different units, each one of them having only one RS232 port. The use of a TBOX accessory, called multi-RS232 splitter (ACC-SPLIT), allows multiplexing communication with each device. The TBOX is automatically switched from one UPS to the next one at very high speed and performs its read/write operations. Two mV to Volts converters (ACC-SHUNT) are used to measure the solar radiation. Monitoring the application via WEB browser can be done locally and remotely by PSTN.

Once per day, a statistical report is sent by email to Total Energie, the contractor of this project. The historical database stored in TBOX is attached to the email. This daily report displays the efficiency of the application, the hours of sunshine and the CO2 gain.