Signs of the Times - March 2012 - (Page 34)

LIGHTING TECHNIQUES By Marcus Thielen Marcus Thielen is a physicist and lighting-industry consultant from Duisburg, Germany. Solar-powered Signs Many considerations arise if you’re examining this option. In 2011,service competitive, any to be good or had to be “green”, “eco” or have a “carbon-neutral footprint”, regardless of the facts. Small-scale power generation, by means of wind turbines and photovoltaic panels, are replacing more and more of the power generation from nuclear and other non-recycleable resources. Power-grid-independent illuminated signage, especially for signs and billboards destined for rural areas, are selling strong. This column will shed some light on major points to consider when planning and erecting solarpowered, illuminated signage. Solar panels Solar (photovoltaic) panels, in a simple view, can be seen as LEDs “run in reverse”. These semiconductors generate low-voltage DC electricity when light shines on them. (In larger installations, many panels are connected in series to generate more than 600V, so always assume a low-voltage installation can be deadly.) However, solar panels deliver power only when there is light, and their output is proportional to the amount of light received. This isn’t practical for the sign business, because we want the sign brightly lit when it’s dark, not just when the sun is up. It demands energy storage, the way a rechargeable battery holds energy generated in daytime until it’s used at night. The lead-acid type is still the most economical and ecological rechargeable battery. (It can be completely recycled with much less effort than other, secondary battery types.) Car and truck batteries with 12 or 24V would match many common, LED-module voltages. Solar-powered signs are NOT limited to LEDs as lightsource. Most manufacturers of electronic, neon power supplies offer 12 or 24V units. Also, many low-voltage, DC-powered fluorescent lamp ballasts, or “energysaving” compact fluorescent lamps for 12 or 24V supply, are available even at home-improvement stores. Especially for poster-panel edge lighting, cold-cathode, fluorescentlamp (CCFL) lighting (nickname: spaghetti tubes) is best suited because it provides a confined, intense line of light (contrary to the spots that come Photo credits: Alpha signs, Leipzig Fig. 1: The solar-powered sign on the building facade Fig. 2: This solar-panel installation in a Munich, Germany, parking lot, which powers the sign on the building, is meant to be an architectural element. Note the inclined mounting angle of the solar panels. Surplus power is fed back into the grid. 34 SIGNS OF THE TIMES / MARCH 2012 / www.signweb.com http://www.signweb.com

Table of Contents for the Digital Edition of Signs of the Times - March 2012

Signs of the Times - March 2012
Contents
ST Update
Technology Update
Vinyl Apps
Strictly Commercial
Lighting Techniques
The Moving Message
Technology Review
Sign Museum News
New Products
The 2012 International Sign Contest
Get Smart
The Value of Signs
Industry News
Advertising Index
Editorially Speaking

Signs of the Times - March 2012