Glossary

Passive Solar

The design and siting of a building to maximize the effects of such natural processes as evaporation and heat flow, as opposed to active systems which require mechanical devices.

Peak Demand

The greatest electricity requirement placed upon the generating equipment of an electric utility during a specified period of time, for instance, one hour. The highest demand time is usually mid-afternoon during the summer months.

Phantom (or Vampire) Load

The amount of energy a device consumes while in standby mode or switched “off.”

Plug Load

The energy consumed by any electric device that’s plugged into a socket.

Power Usage Effectiveness (PUE)

The recommended metric for characterizing and reporting overall data center infrastructure efficiency.

Process heating or Cooling Waste Heat Recovery

An energy conservation system whereby some space heating or water heating is done by actively capturing byproduct heat that would otherwise be ejected into the environment. In nonresidential buildings, sources of waste heat include refrigeration/air-conditioner compressors, manufacturing or other processes, data processing centers, lighting fixtures, ventilation exhaust air, and the occupants themselves.