As AV products and systems proliferate throughout organizations, power consumption becomes a growing issue. Fortunately, equipment suppliers are already working on the issue.

Displays

Flat panel displays from the factory are almost always overdriven with the brightness maximized, black levels buried, and the color over saturated -- they look more “impressive” in the showroom that way. Proper calibration can reduce the power required to produce an accurate image in terms of color space, brightness, and contrast. With a single display, the result may not be significant energy savings, but in a multiple display application, energy savings and extended display life can become significant.

Projectors

Two of the leading projection engine technologies in business-class projectors (less than $15,000) are single-chip DLP (digital light processing) and 3-chip LCD (marketed as 3LCD).

The 3-chip optical engine of a 3LCD projector uses a dedicated imaging chip for each of the three primary colors of light (red, green, and blue). Dichroic mirrors allow certain colors of light to be reflected and other colors to pass through. A single-chip DLP system uses a color wheel that only allows one color through at a time -- if red is going through the color wheel, blue and green light is reflected back towards the lamp, and so on. To compensate for this loss of light, higher wattage lamps are used to create the same lumen levels as their 3LCD competitors. According to 3LCD, higher wattage lamps result in more energy consumption and more heat output. Makers of 3LCD projectors claim an efficiency advantage of up to 25 percent over single-chip DLP designs.

With larger projector designs, the playing field becomes more level. Larger DLP projectors use 3-DMD (digital mirror device) chips. For both single and 3-chip DLP products, design innovations like Digital Projection’s CoolTek combines a number of features that promote energy conservation in its products. Depending on the projector model, up to three primary design principles contribute to the CoolTek benefits:

• Efficient designs. As a result of proprietary illumination and optical designs, DP claims their products use lower wattage lamps and consume around 50 percent less power than comparable products.

• Thermal management. Active cooling of the DMD’s inside the light engine allows maximum illumination to be directed to the DMD while ensuring the device operates well below thermal limits. Filtered cool air moves through the chassis with few obstructions and few turns, minimizing back pressure as well as noise due to airflow turbulence.

• Small, quiet, low weight.As a result of the first two design elements, DP claims that it minimizes the environmental impact of its projectors.

Audio Amplifiers

Audio power amplifiers are large consumers of electrical power. Even when “idling,” they can draw up to an amp of current. In actual applications, they can draw anywhere from 10 to 20 amps or more. Actual power or current consumption depends on many factors, including amplifier and power supply designs, the type and impedance of the “load,” line voltage, and the source signal. Efficiency is the power output of a device divided by the power input to the device. Like lighting, power input that is not outputted by a system is dissipated as heat from the system. The greater the efficiency of an amplifier, the less AC power is required to deliver the same output power to the load.

Amp Designs     Power supply designs
Class A:     26%    Type 1 (Standard, analog): Up to 80%
Class B:     Up to 75%    Type 2 (switching): Up to 90%
Class C:     Up to 90%
Class D:     Up to 90%
Class AB:     Up to 65%
Class H:     Up to 65%

Power Protection

Some surge protection devices offer “master/controlled” outlets that can automatically cut power to unused equipment, thereby reducing utility costs and energy.

System Control

AV control systems can have a dramatic effect on power consumption of individual AV products.

1. Use IP-based asset management tools to shut down devices/subsystems when meeting rooms and building areas are not utilized or after hours. Also, you can intelligently schedule lighting to maximize natural light, and turn off standby power on devices/sub-systems that are not in use.

2. Use automated lighting and window shades. Programming lights to shut off based on meeting schedules and/or motion sensors, dimming lights and adjusting shades to maximize natural/ambient light, and programming exterior lights based on the astronomical clock can cut light and HVAC consumption in half.

3. Use products specifically designed to conserve energy and minimize environmental impact.

4. Integrate AV control with building management systems. This allows building managers to control every device/sub-system directly from the same touch panel.

5. AV control system manufacturers are leading the effort to allow LEED (Leadership in Energy and Environmental Design) points in nine different environmental categories designed to reduce energy consumption.
[Sources: Alan Brawn Consulting, AMX, APC, Crestron, Digital Projection, 3LCD]


Power Consumption Compared
Average rear-projection:211 watts (0.13 watt per square inch)
Average plasma: 339 watts (0.33 watt per square inch)
Average LCD: 213 watts (0.28 watt per square inch)
Average PC: 78 watts
DirecTV HR20 DVR: 33 watts
Wireless router: 7 watts
[Source: CNET]