Energy Efficient Lighting Technologies and Practices

Satish Kumar, Ph.D.Lawrence Berkeley National Laboratory

Public Sector Energy Management WorkshopMumbai, India

September 20, 2005

The Electromagnetic Spectrum

Brief History of Lighting

Compact fluorescent lamp has improved the product of efficacy and lifetime 50-fold compared with the tungsten-filament lamp and by half a million compared with the candle.

Potential of Lighting Technologies

Switching two-thirds of the half-billion incandescent downlights in the U.S. to compact fluorescent technology would save customers $3billion per year in electricity bills, slash maintenance costs, and free up 7,000 megawatts of peak capacity.

Recommended Lighting Levels

Lighting Quality

• Color Temperature: Light sources emit light that is perceived as having different “whiteness.” Incandescent lamps have a yellowish-white light, whereas many fluorescent sources and midday sunlight are perceived as having a bluish-white appearance.

• Color rendering index (CRI). Measured on a scale of 0 to 100, CRI conveys the ability of a light

source to accurately convey a sample of eight standard colors, relative to a standard source with excellent color rendering that has the same color temperature.

The CRI averages the rendering of the eight colors; the higher the average value, the better the source, presumably.

• A cool white fluorescent has a CRI of 62 to 70; • T8 lamps range from 75 to 98; • Standard high-pressure sodium lamps have CRIs of about 27.

Lighting Quality

• Color Temperature 3,500K is a good average level for most facilities Lighting sources with different color temperatures should

generally not be mixed in near proximity to each other.

• Color rendering index (CRI). Use the highest CRI you can afford—go for 75 or higher—but be

aware that the cost of fluorescent lamps generally increases as the CRI increases.

Avoid mixing sources in near proximity that have different color rendering, because they will impart different appearances to people and furnishings.

Lighting Efficacy

• Lamp converts the electricity it receives in light and heat.

• Number of lumens that a lamp and its ballast (if there is one) produce per watt of power For example, a 100-watt incandescent lamp that supplies

1,800 lm has an efficacy of 18 lm/watt. Check whether ballast losses are included in an efficacy

value (often add 20% or more to fixture power consumption).

• Why the term efficacy instead of efficiency? Because efficiency is a measure of some quantity, such as

power, at the output of a device, divided by that same quantity at the input to a device (no units)

Efficacy, on the other hand, is a measure of the output of a lamp in lumens, divided by the power drawn by the lamp or ballast in watts (lumens/watt)

Typical Lamp Efficacy of Major Light Sources

Lamp Lumen Depreciation

Accounting for Dirt Depreciation

Even in clean office environments, 18 months of dirt buildup can reduce light output by 10 percent

Environmental Issues

• Mercury Some forms highly toxic

Can pollute groundwater and affect marine and wildlife directly and humans indirectly

Permanent neurological and kidney damage Used in the fluorescent lamps and HIDs

Amount required has been decreasing A 4-ft T12 lamp needs only 0.1 mg theoretically Used to be 50-100 mg in 1970s but only 5-10 mg now

Lamps containing mercury should be disposed off according to local environmental regulations or better

Procurement guidelines should encourage lighting products with low-mercury content

Environmental Issues

• Polychorinated biphenyls (PCB) Exposure to highly toxic PCBs causes skin, liver, and

reproductive disorders and may cause cancer in humans Used in magnetic fluorescent and HID ballasts Banned in many countries

Manufacturers are required to tell if ballasts contain PCB Procurement guidelines should ban the use of ballasts using

PCB, if it is no already Existing ballasts that contain PCB should be disposed per

existing environmental regulations or better

Best O&M Practices to Conserve Energy With Room Air-Conditioners

• Simple operations and maintenance procedures will help reduce the energy consumption of room (or “window”) air conditioners, all with little to no sacrifice in comfort.

• Smart operations are probably the most beneficial aspect to keep in mind.

• Following the few rules on next page should significantly decrease the amount of energy consumed by your facility’s room air conditioners (RACs)

Energy Efficient Operation Tips for RACs

• Turn it off Room units should be turned off whenever the room is not expected to be in use for an

hour or more. • Keep it clear

Remove obstructions (e.g., furniture or piled books) to air passage to the unit. RACs operate most efficiently when intake and discharge airflows are free from nearby

obstacles in the room.• Use “energy saver” or “automatic” fan modes

This saves energy by only cycling the fan on when the compressor is running. It also reduces humidity in the space by minimizing the entrainment and re-evaporation

of condensed water from the inside coil. • Avoid fresh air intake

When outdoor air is warmer and contains more moisture than the conditioned air, intake of this outside air will compromise efficiency.

Natural leakage through windows and doors will generally supply sufficient outdoor air for assuring health and minimizing odor.

When outdoor air conditions are more desirable than inside (e.g., on cool summer nights), “fresh air” or “ventilation” modes can be beneficial where the simpler alternative, opening windows, is not possible (or sufficient).

Maintenance Tips for RACs

• Seal it Make sure, upon installation and routine maintenance, that the unit

is well-sealed from the outdoors. Air leakage can compromise both comfort and efficiency. “Caulk” can be applied to seal the area around the RAC in case of

a poor fit.• Clean filters

This should be done at least annually. Follow the manual’s instructions for removal and cleaning

(usually with a vacuum and/or water).• Clean outdoor coils

Clean these coils when they become occluded. While research has shown limited benefits to frequent coil

cleanings, efficiency degrades in dusty conditions, and especially when layers of dirt and mud are evident.

Monitoring Plan to Evaluate Performance of RACs

• Evaluate the performance of two new RACs of same cooling capacity but with different performance specifications (SEER)

• Evaluate the performance of two identical RACs (one old and one new)

• Evaluate the impact of best O&M practices for RACs on energy consumption Operate under identical conditions Operate for the same duration Work out the details with PWD Team

Credits

• This presentation is put together using materials from: E Source Lighting Technology Atlas Series

(2005 version) Research and analysis conducted at Lawrence

Berkeley National Laboratory Special thanks to Phil Coleman for his work on

O&M of RACs