# Presentation: 570114

## Energy Efficient Lighting Technologies and Practices

- Satish Kumar, Ph.D.
- Lawrence Berkeley National Laboratory
**Public Sector Energy Management Workshop**
**Mumbai, India**September 20, 2005

## The Electromagnetic Spectrum

**Notes:**
The shortest-wavelength radiation our eyes can detect is violet light at about 380 nanometers (nm); the longest is red light at about 770 nm.

## 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.

**Notes:**
The scale is physically correct but may seem intuitively backward; the higher the color temperature, the “cooler” or bluer the light. Incandescent lamps have a color temperature
of about 2,700 K. Fluorescent lamps generally range from 3,000 K for the warm white lamps to about 4,100 K for cool white lamps. However, fluorescent lamps designed for use in homes are available with a 2,700-K phosphor to match the color of incandescent lamps. Daylight typically ranges from 5,000 to 10,000 K.
One should use the CRI with caution, however. A high average CRI value may mask wide variations in the lamp’s rendering of individual colors. It may be very good at rendering the eight standard colors, for instance, but be poor at rendering a color that doesn’t happen to be one of the eight.

## 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.

**Notes:**
Values well above 3,500 K may impart a cooler ambiance and, at typical indoor light levels, may make people and furnishings look less attractive. Temperatures below 3,500 K may make people look too pink. In some applications, such as retail display, other color temperatures may be more appropriate and should be carefully selected by skilled designers in consultation with the client.

## 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)

**Notes:**
However, a lot more than the efficacy of the lamp and ballast determines the efficiency with which electricity gets turned into useful, high-quality light on the task. The most efficacious light source is worthless if it is enclosed in a poor fixture that traps much of the light or reflects it at angles that cause eyestraining glare. Moreover, high-efficacy lamps can produce poor-quality light. High- and low-pressure sodium lamps have the highest efficacies available, but the light they produce generally has poor color and color rendering.

Finally, manufacturer-rated lumen output is measured with a defined lamp orientation and temperature, but real-world conditions may differ widely from the laboratory, leading to different—generally less—light output than product ratings may suggest. Compact fluorescent lamps (CFLs), for example, are traditionally rated at 25° Celsius (77° Farenheit) in a base-up orientation. The efficacy of some CFLs can be 20 percent less in field applications where they are subjected to hotter conditions in a sealed fixture and mounted in a base-down position

## Typical Lamp Efficacy of Major Light Sources

## Lamp Lumen Depreciation

**Notes:**
Light output of lamps decline over time

## 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

**Notes:**
The cost of collecting, transporting, and recycling used lamps varies between 10¢ and 15¢ (U.S.) per linear foot of lamps, and discounts are available for higher-volume customers. This amounts to an average of 50¢ per 4-foot lamp. By comparison, it costs about $46 to operate a T8 lamp and electronic ballast for the rated lamp life of 20,000 hours (including ballast losses and assuming 8¢/kWh of power). Although the disposal cost of 50¢ per lamp is small in relation to operating costs, it will add up over thousands of lamps and could affect a facility’s waste disposal budget (which is rarely connected to its energy budget). This cost should be considered in the economic evaluation of lighting design options and favors the use of reflectorized fixture designs that reduce the number of lamps (and perhaps ballasts) that will need to be disposed of in the future.

Incineration
Uncontrolled incineration can be very damaging because they produce highly volatile mercury vapor
Landfilling
Recycling

## 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**