Introduction
Utility company power bills are usually a large part of the operating expenses of a facility. To reduce the amount of money spent each month on electricity, engineers must understand the billing methods used by the utility. Saving energy is more complicated than simply turning off unnecessary lights. The amount of money that can be saved through a well-planned energy conservation effort is often substantial. Reductions of 20% are not uncommon, depending upon the facility layout and the extent of energy conservation efforts already under way. Regardless of any monetary savings that might be realized from a power-use-reduction program, the items discussed here should be considered for any well-run facility.
The rate structures of utility companies vary widely from one area of the country to another. Some gen- eralizations can be made, however, with respect to the basic rate-determining factors. The four primary parameters used to determine a customer’s bill are
• Energy usage
• Peak demand
• Load factor
• Power factor
These items often can be controlled, to some extent, by the customer.
Energy Usage
The kilowatt-hour (kWh) usage of a facility can be reduced by turning off loads such as heating and air- conditioning systems, lights, and office equipment when they are not needed. The installation of timers, photocells, or sophisticated computer-controlled energy-management systems can make substantial reduc- tions in facility kWh demand each month. Common sense will dictate the conservation measures applica- ble to a particular situation. Obvious items include reducing the length of time high-power equipment is in operation, setting heating and cooling thermostats to reasonable levels, keeping office equipment turned off during the night, and avoiding excessive amounts of indoor or outdoor lighting.
Although energy conservation measures should be taken in every area of facility operation, the greatest savings generally can be found where the largest energy users are located. Transmitter plants, large machinery, and process drying equipment consume a huge amount of power, so particular attention should be given to such hardware. Consider the following:
• Use the waste heat from equipment at the site for other purposes, if practical. In the case of high- power RF generators or transmitters, room heating can be accomplished with a logic-controlled power amplifier exhaust-air recycling system.
• Have a knowledgeable consultant plan the air-conditioning and heating system at the facility for efficient operation.
• Check thermostat settings on a regular basis, and consider installing time-controlled thermostats.
• Inspect outdoor-lighting photocells regularly for proper operation.
• Examine carefully the efficiency of high-power equipment used at the facility. New designs may offer substantial savings in energy costs.
The efficiency of large power loads, such as mainframe computers, transmitters, or industrial RF heaters, is an item of critical importance to energy conservation efforts. Most systems available today are significantly more efficient than their counterparts of just 10 years ago. Plant management often can find economic justification for updating or replacing an older system on the power savings alone. In virtually any facility, energy conservation can best be accomplished through careful selection of equipment, thoughtful system design, and conscientious maintenance practices.