Solar Power for Intersection Control
Complete traffic control systems powered by 12 or 24 VDC
Solar Power has been used for many years in the traffic control industry because it is a readily available form of free energy; however, its application has been limited mainly to flashers, warning signs and regulatory signs. Little work has been done by major traffic industry suppliers to operate complete intersections on solar power. This is because the DC power generated by solar cells has to be inverted to 120 or 240 VAC to operate the traffic traffic control equipment, resulting in additional expense and energy losses.
Zwiesler Resources Inc. (ZRI) is on the leading edge of technology to run entire intersections using solar power. This includes all SBC-2400 Traffic Control System components, which can be powered directly from 12 or 24 VDC. ZRI has also established close working relationship leading suppliers of solar panels and related photovoltaic hardware for traffic control applications.
LED signal heads and pedestrian signals consume less then one tenth of the power as their incandescent counterparts, and are available for 12 VDC, 24 VDC, 120 VAC or 240 VAC power. To convert the DC power from solar cells to AC power, ZRI is offering low-cost power inverters with typical
90{4d5adc411031a5aa26d82d354dcf3b228ad26ec8f4fe63eb7e3163dad9af273d} to 93{4d5adc411031a5aa26d82d354dcf3b228ad26ec8f4fe63eb7e3163dad9af273d} efficiency.
There are three main items to be considered when planning a solar installation:
Location – Availability of sunlight. Includes latitude, longitude, altitude & climate.
Load – Intersection power consumption.
Duty cycle – Intersection operation as a percentage of time out of 24 hours.
For example, if an intersection operates in flash at night time, when direct solar power is not available, battery and other solar hardware costs can be reduced compared to full 24-hour intersection operation.
Solar Intersection Example
Intersection description: Two streets crossing at 90°. Four 300 mm (12 inch) LED signal heads (R, Y, G), four LED pedestrian signals, one traffic cabinet.
Power consumption of 12″ signal heads: 12W x 4 = 48W
Power consumption of pedestrian signals: 10W x 4 = 40W
Power loss due to inverter inefficiency (7{4d5adc411031a5aa26d82d354dcf3b228ad26ec8f4fe63eb7e3163dad9af273d}): 6W
Power consumption of traffic cabinet components: 8W (667 mA @ 12V)
Total power consumption: 102W (8.5A @ 12V)
Recommended solar cell power generating capacity: 200W
Battery capacity for 16-hour operation from one charge: 8.5A x 16 hrs = 136 Ah
Recommended storage battery: Lead acid gel-cell, 186 Ah, 50 x 20 x 25 cm
Your Next Step
Contact ZRI. We will be happy to quote entire solar powered intersections, or work with you on a consulting basis to develop a requirements package for procurement of components from different sources.
