Guidelines for Installing and Using Low Voltage and Solar Landscape Lighting
Filed Under Low Voltage Landscape Lighting, Solar lighting | Leave a Comment
General Principles of Low Voltage Lighting
The issues to consider when plaaning the installation of low voltage landscape lighting include factors such as:
- How close the light is to the area to be lit (low voltage and solar light5s are not as bright as mains lights)
- The color of the walls and other structures close by (light, shiny colors reflect light, but dull or dark colors absorb it)
- The use of diffusers and shades over the light
- The use of reflectors to direct the light
It can be worthwhile to purchase a few different low voltage lights to which ones best suit your requirements in different locations.
Generally low voltage lighting is used for outdoor and landscape lighting, but some people do use it indoors to light a whole house.
For this reason you may use a lot of lights for a solar system, so you have a low and a high wattage light for the same area. This means you can use the lower powered light when you don’t need a bright light.
Indoor Low Voltage Lighting
Consider “task lighting”, which is the approach where you only light up the area you need. For example don’t use a 100W to light a whole room when a 20W desk lamp will do the job.
Also, bring your lights close to where you need them. So if your ceiling is high, suspend your light lower down, close to where you require it and use a reflector type shade to direct the light downwards.
Diffusers over fluoro lights make the light more atractive, but they restrict the light output, plus they can often collect bugs inside. Also in warm climates they can decrease light output by up to 20% by causing the tube to overheat.
Outdoor Low Voltage Lighting
For outdoor lighting consider the use of motion detectors to turn the light on and off automatically. The timer is usually adjustable for between 1 - 10 minutes. Also delay switches can turn off lights, in say corridors, several minutes after being switched on so they don’t get left on unnecessarily.
Types of Lights
There are four main types of low voltage lights. In order of decreasing efficiency, the lights are:
- Fluoro
- LED
- Halogen
- Incandescet
FLUORO LIGHTS:
These are approx. 3 times more efficient than an incandescent bulb, meaning a 20W fluoro is roughly 3 times brighter then a 20W bulb.
Most modern fluoros come in a variety of warm colors and do not emit the rather cold blue light that was the norm 10 - 20 years ago.
Fluoros are the best choice for most of your lighting requirements due to their high efficiency. Their light output decreases after several thousand hours of use when they should be replaced.
LED LIGHTS:
LED emit a bright light in a variety of colors and becoming popular becuase of their efficiency, small size and robustness.
HALOGEN LIGHTS:
These lights run at higher temperatures than a standard incandescent bulb and they are about 30% more efficient and produce a whiter light similar to daylight that brings out ‘natural colours’.
They have a normal life of about 2000 hours for a 12V 20W bulb, double that for a lower powered 5W bulb, half of that for a 24V bulb. Stop’ to filter out most harmful UV rays and they are dimmable.
Warning:
Halogen bulbs are made to operate in 12.0 or 24.0 Volts and not on typical battery voltage (about 12.6 Volts for a fully charged 12V battery). Life expectancy may be decreased by as much as 50% by 5% over voltage (eg: 0.6V on 12V) and by about 75% by 10% over voltage.
So if you turn on these lights during the day when solar panels are charging, or use them with a generator back up at night, without proper voltage regulation, you could be subjecting the bulbs to over-voltage - up to say 15.0 Volts - which will greatly reduce their life.
Also, if you run your halogens off a old, unregulated, transformer type converter from mains supply, you can get over voltage if one bulb burns out or if you use less wattage bulbs than specified by the transformer, so remember to replace failed bulbs promptly.
12 VOLT INCANDESCENT BULBS:
These are the traditional, cheapest and least efficient type of bulb. They produce a yellow light and are usually rated for 1000 hour life span.
The advantages are they are cheap and readily available, the disadvantage is their power consumption.
Solar Powered Building & Lighting
Filed Under Environment Friendly Outdoor Lighting, Solar lighting | Leave a Comment
The new Ohlone College campus in Newark CA is nearing completion with the campus is scheduled to open for classes in January 2008.
The site will be the first “green” campus in the nation, designed to achieve LEED (Leadership in Energy and Environmental Design) [Note 1] Gold or Platinum level certification when the building opens for classes in 2008.
The building has been built to the highest standards of environmental sustainability using best practices of energy conservation. Interestingly, only around 50 buildings in the world have achieved Platinum certification todate.
We suggest that solar electricity is a sensible choice for outdor lighting and Ohlone has gone to town in asolar sense - they have installed 1585 Photovoltaic panels (PVP) on the building’s roof that will provide up to 50% of the building’s energy needs!
Not surprisingly, this is currently the largest installation of PVP panels in the Silicon Valley.
Also of note, as part of the environmental design that qualifies for LEED recognition, the college is using an exterior lighting system with cutoff fixtures to maximize landscape lighting whilst eliminating light pollution in the neighborhood.
Again, the issues of energy consumption and light pollution are imortant design factors in your landscape lighting system. Your objective should be to minimize both aspects.
Note 1: The LEED green building rating system is developed and administered by the U.S. Green Building Council and is designed to promote design and construction practices that increase profitability while reducing the negative environmental impacts of buildings and improving occupant health and well-being.
The LEED rating system offers four certification levels for new construction — Certified, Silver, Gold and Platinum.
Stay tuned for information on environmentally friendly outdoor lighting and solar lighting systems.