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Energy and Technology

A Quick Overview
To understand your technology systems’ electrical requirements and their related costs, let’s lay a little basic groundwork. Using and office computer as an example can show how rapidly the electrical expenses in even a simple deployment can accumulate. A typical desktop computer will cost a school district just under two cents for each hour of use. (This number may be higher or lower, depending on where your school is located and how much you pay for electricity.) At first glance, this seems like a negligible expense. Assuming that the computer is left on for an entire eight-hour work day, the electrical cost is about 16 cents. Leaving it on overnight increases the total cost to about 48 cents. Still not much to worry about, is it?   However, multiply that amount by the 250 or so computers in an average administrative service center. Even if every unit is turned on when staff members arrive in the morning, and then turned off when they leave at night, the cost is around $40 a day, or about $200 a week. In a 261-day work year, that comes to about $10,440-certainly an expense worth taking into consideration, and even more so when the cost of electricity may double or quadruple in many parts of the country next year. When you extrapolate the cost to include, for example, my district’s current deployment of almost 7,000 workstation and peripherals, the numbers become almost staggering.

Electrical terms to know Amps: An amp (more correctly an ampere) is a unit of electrical current within a circuit. Volts: This is a measurement of “pressure” on the units of electrical current in a circuit; it basically measures electrical force. Watts: This is the measure of how much energy an electrical device uses per hour.  You’re probably most familiar with the term “watt” in relationship to light bulbs.  A 60-watt light bulb uses 60 watts of electricity per hour, a 100-watt bulb uses 100 watts per hour, and so on.  The higher the wattage, the more electricity is used to drive the device.           Many high-tech equipment labels do not list the appliance’s wattage. A simple mathematical formula, however, can calculate the wattage of a given piece of equipment, provided you hve the appliance’s voltage and amperage.  Wattage = Volts x Amps           For instance, a Dell M770 17-inch monitor is rated at 100 volts and 1.8 amps.  Wattage is therefore 180 watts. Kilowatt-hour: This is the basic unit of electrical energy used by the power company. All your billing is kiowatt-hours and reflects the use of 1,000 watts (a kilowatt) of power per hour. Ten 100-watt light bulbs use 1 kilowatt of electricity per hour. Rated load: This refers to the load calculated and presented by the manufacturer on its equipment’s data plate. These are the numbers that most organizations use to estimate electrical power consumption for a given device. Measured load: This term refers to the average energy use over a given period of time. A computer’s energy use changes during the time it is left on. For instant, a Dell 15-inch multimedia monitor’s draw for the first one-tenth of a second after the “on” switch is thrown is 207 watts. After that, its run-time output is 90 watts. This is less than the rated load of 200 watts.           It is important to understand that the actual measured loads for computer equipment may be 20 percent to 40 percent of the rated load shown on a device’s data plate.