If you plan to update or expand your lighting system in the near future, you should consider double-ended HPS bulbs and reflectors as an alternative to conventional, mogul base HID systems. Double-ended high pressure sodium lamps are superior to traditional, single-ended HPS systems for a couple big reasons.
1) Longer life! The double-ended design reduces harmonic distortion (read: vibration), resulting in less physical wear on lamp components. Double-ended HPS lamps retain over 90% of their output after 10,000 hours of use, allowing you to replace your lamps less frequently. Since double-ended lamps are under fewer physical stresses , they can be run at a much higher frequency, resulting in:
2) More light! Double-ended HPS lamps run more efficiently and produce an abundant about of light in the PAR spectrum – around 2100 micromoles per second!
The double ended design reduces harmonic distortion by stabilizing the lamp on both ends, allowing for electricity to pass through the bulb with a very high frequency. A double ended lamp operates optimally between 100 kHz and 150 kHz, while a conventional HPS operates between 20 kHz and 60 kHz. Frequency of a lamp can be visualized as a strobe effect – that is, how many times per second a lamp goes on and off. (That’s right – even while your lamps are running, they are not producing light 100% of the time. This can be demonstrated with a digital camera – focusing on your light source, you’ll be able to notice horizontal dark lines scrolling vertically, much like misadjusted tracking on a VCR.)
Standard ANSI s52 electronic ballasts can operate some double-ended bulbs, and is in fact recommended by the bulb manufacturer Ushio to run their Hilux Gro Pro-Plus(link below). However, to run a double-ended bulb optimally, a higher frequency output is needed from the ballast. Currently there are only a few high frequency ballasts available on the market, the leader being Gavita.
Gavita, with their commercial-grade, 400v/100kHz-output electronic ballasts, has partnered with Philips to produce a “true” double-ended greenhouse fixture. Philips developed their GreenPower bulb specifically for use with Gavita’s high-output ballast to maximize the potential benefits of the double-ended technology.
Currently on display at GreenTree is the new Sun System AC/DE Boss (Air Cooled/Double Ended) hood, designed for rooms with lower ceilings and a need to manage heat. Check out the video below for Sunlight Supply’s Comparison test of their AC/DE reflector.
The Ushio Spec sheet can be found here.
Gavita Greenhouse fixtures can be found here.
Stop in and check out our display and we can answer any questions you might have.
--Adam and James