Today, many companies are forming “Green Teams” with the primary objective of reducing the environmental impact of the company’s operations, which usually includes reducing energy consumption. This makes the earth and the bank account greener. The first step when carrying out an energy-reduction program is to determine what is being used and where and when it is being used so that you can determine how to get the most benefit for the least effort.
Such programs are great opportunities for electrical contractors to offer to facilities that don’t have the expertise, the staff or the time to do it themselves. You can take the courses to become a LEED Green Associate. Or, you can learn how much electricity each piece of equipment uses and where there are opportunities to reduce that consumption through maintenance, modified operation or replacement with more energy-efficient equipment that has an acceptable payback period. It takes relatively little investment of time and an instrument for measuring the real power (in watts), the effective use of the power (watts/volt-amperes or power factor) and the harmonic current.
According to the Department of Energy, the electrical energy consumed by residential, commercial and industrial customers 15 years ago was nearly the same amount, with commercial being approximately 10 percent below industrial and residential. Today, commercial facilities consume approximately 50 percent more than industrial facilities. While some of this can be attributed to the continuing shift from a manufacturing base to a service-based economy, the profile and amount of equipment used within a commercial facility has increased significantly. Since commercial and residential customers pay 40–50 percent more for electricity than industrial customers, this makes energy-reduction programs even more attractive. Heating, ventilating and air conditioning (HVAC) electrical usage typically accounts for 32 percent of the bill in commercial facilities, while information technology (IT) equipment accounts for 11 percent, and lighting uses 23 percent.
Obtain a copy of the electrical bills for the past year to help determine what the cooling versus heating financial impacts are. Next, a walkthrough of the facility— starting at the service entrance—will help create a list of action items, including both maintenance and equipment replacement candidates. Tally up the number of lighting fixtures and IT equipment, and note their models. Repeat the walkthrough shortly after close of business because unnecessary lights, copy machines, and computers left on overnight and on weekends, along with inappropriate settings for the HVAC system, are instant savings opportunities. It may take the addition of switched outlet strips to get the full savings, as most electronic equipment still consumes energy in standby mode.
Making a simple table of quantities and estimated (or nameplate) wattage per piece of equipment can help determine where to further investigate. If the facility has a power monitor at the service entrance or you are able to install one for a week to monitor the demand levels at various times of day, you can use this information to verify your calculations as well as reveal other potential savings opportunities. For example, the figure above shows the effect of manufacturing shutting down its processes at 15:30 (30 kW), followed by the office portion at 18:00, and then all of the lights (60 kW) at 18:30. The baseload (45 kW) is for the HVAC (on unoccupied setting), security lighting, and all of the IT loads that are left on all of the time.
The load that should have been off is most likely the air conditioning system, as 70 kW is similar to the difference in average daily operating values in the summer versus fall. This can be compared against the nameplate ratings of the HVAC units to see if it is reasonable. It may also necessitate maintenance or even replacement if the payback period is reasonable.
Developing a realistic plan to achieve 10 percent savings on the facility’s electricity costs can be done without an investment in energy-efficient lighting, motors and IT equipment. It just takes an electrical contractor who is knowledgeable about how and where energy is used.
BINGHAM, a contributing editor for power quality, can be reached at 732.287.3680.