Don't Waste Your Energy!
While moldmakers are busy design-ing, building and repairing molds, in addition to trying to keep costs down in today's competitive marketplace, they often overlook energy consumption in the shop. Areas like electricity, heating and lighting warrant a closer look to keep your business running at peak efficiency. Increasing the efficiency of energy-using systems will decrease the total costs for energy, which will, in turn, increase profitability. Managing energy costs is no different than any other type of cost management. The following are primary cost management factors:
- What are your fixed costs?
- What are your variable costs?
- Where can dollars be saved through enhanced efficiency?
- What level of capital expenditure is required to implement those efficiency improvements?
- How long will it take for those capital investments to pay for themselves through cost savings?
Get an Energy Audit
An energy audit provides information on current energy use patterns and recommendations for savings through the implementation of energy conservation measures (ECMs). A comprehensive energy audit will help determine exactly where energy is used within a manufacturing facility and what processes use the most energy, thereby helping target those areas with the greatest opportunity for energy savings. Frequently, ECMs can provide savings beyond energy, such as operational and maintenance savings. More efficient systems will typically last longer and incur less maintenance. Maintenance of energy-using systems should be among the highest of priorities and an ongoing function of daily operations. Energy brokers have the analysis tools needed to evaluate energy usage patterns and the best energy alternative for a facility. However, it is important to keep in mind that brokers want to sell you energy. Hiring an independent energy consultant who can find opportunities for energy savings can provide you with an objective and unbiased opinion of the best strategy for your facility.
Furthermore, an independent energy consultant can help you create a request for proposal (RFP) that will request competitive bids for energy services, thereby facilitating an objective comparison - based upon the criteria set forth by the RFP - of your energy options.
Understand Your Utility Bills
Understanding your utility bills is the first step to knowing where you need to work on managing your energy use.
Electric Utility Bills
Electric bills can be difficult to understand due to the various rate tariffs and miscellaneous fees. However, regardless of the rate tariff that your bill is based upon or the fees that apply, most bills contain three main components. First, energy demand (kW) is the amount of electric capacity that the utility must provide you so your plant can operate. A second component is demand charges, which are typically based on facility-wide peak demand for the given month. Typically, demand costs vary between the heating and cooling season. Third, energy use (kWh) is a function of the amount of time that an energy-using system is operated. For example, a certain motor that consumes 10 kW (demand) might be operated for only an hour per day and 20 days (on average) per month/ billing cycle. The charge for energy use (per kWh) can vary by time of day use (peak and off-peak) or vary based upon the kWh used in discrete amounts (non-time of day).
Natural Gas Utility Bills
Similarly, there are three main groups of charges that apply to gas utility bills. Gas use (measured in Therms, cubic feet or MMBtu) is measured and charged for based on the prevailing gas market price. The recent escalations in natural gas prices seen throughout the United States resulted in an increase in this charge on your gas utility bill. For many rate tariffs, the price per unit decreases as more gas is used. The transportation charge is what the local gas utility levies for delivering gas to the customer, and other costs are all other fees and taxes included in this section.
See the Light
Lighting is frequently one of the first areas considered when trying to save energy because several energy conservation measures are simple and inexpensive, and these efforts should be considered for both process areas as well as support areas (administration offices). There are several ways to save money on your lighting energy, such as installing more efficient lighting, using automated controls and performing necessary maintenance.
Most existing fluorescent systems use T12 lamps with magnetic ballasts. T12 lamps are inexpensive and reliable, but they have several disadvantages. For example, T12 light fixtures draw power (about 6.5 watts) even when lamps are burned out. New T8 lamps with electronic ballasts are far more efficient and typically pay for themselves within a few years. When retrofitting a T12 lighting system, either the whole fixture can be replaced in its entirety or just the ballasts and lamps can be replaced with T8 components. T8 systems have many advantages over T12 systems, including improved efficiency, the ability to be dimmed, reduced heat output and zero energy use when lamps burn out.
Incandescent fixtures can be replaced with compact fluorescents, and replacing incandescent exit signs with newer kits can provide additional efficiency improvements. A relatively new technology available to improve lighting system efficiency is high intensity fluorescent (HIF) lighting - designed to replace high intensity discharge (HID) lights such as metal halide and sodium vapor lamps. There are many advantages that HIF lights have over HID lights that enable HIF lights to not only be more cost effective, but also allow HIF lights to provide superior lighting, including higher energy efficiency, more versatile dimming options, near "instant on" start-up, better color rendition and less glare.
Of course, the most obvious measure - yet often neglected one - is to turn lights off when they are not needed. Lighting is often left on during periods when no one is present, which is extremely energy inefficient and provides no discernible benefit. Ideally, plant personnel should turn lights off when work areas are not being occupied. A better strategy is to install occupancy sensors that automatically turn lights out when no one is present.
Using daylight as a source of illumination offers a tremendous potential for savings. Lighting levels can be reduced and often eliminated in areas with skylights or large windows, which is especially important because using natural light will save energy during the day, when electricity is most expensive. If there is not enough daylight to turn lights off entirely, consider moving to a dimmable lighting system controlled by light sensors. In order to utilize this control strategy, T-8 fixtures with dimmable ballasts are necessary. T-12 fixtures are not capable of being controlled with dimming technologies.
As far as lighting maintenance goes, replace burned out lamps and disconnect unused ballasts. Remember, with T12 lighting systems, both burned out lamps and unused ballasts use energy even though they are providing no light, so make sure to fully disconnect any unused ballasts. Also make sure to properly clean lamps when necessary to ensure optimal lighting levels.
Heating, ventilation and air conditioning equipment (HVAC) is used to maintain temperature and humidity in buildings. To save money on HVAC heating costs, simply reduce the overall temperature of the building. Rule of thumb proposes that by reducing the temperature set point by just five degrees Fahrenheit, a facility can expect an approximate 15 percent reduction in their heating bill.
If your plant does not have a thermostat control capable of running a nighttime setback temperature, have one installed. Thermostats capable of performing setbacks pay for their installation almost immediately.
Another option is to consider a strategy of using infrared heating located at the workstations and reduced temperature setpoints on existing forced air systems, which is very effective at reducing gas forced-air heating use while maintaining comfort for plant personnel when working at their workstations. Lastly, heating and process boilers should be tested regularly for combustion efficiency. If combustion efficiency drops, boiler repair contractors can clean and tune boilers to restore efficiency back to optimal levels. Typically, the cost of tune-ups is paid back through energy savings in less than one year.
Air It Out
Among the most conspicuous electrical energy users in almost every shop is compressed air, but it also affords excellent opportunities for energy conservation. Overall compressed air system efficiency should be a factor when selecting compressors and ancillary equipment. Compressor energy efficiency improvements can be realized by addressing operational efficiency in the following areas:
- System leakage - fix leaks immediately.
- Heat recovery - an unavoidable byproduct of compressing air. Purchase heat recovery equipment.
- Overall compressor efficiency - select a compressor based on the operating profile of the shop and part load efficiencies.
- Compressor control - there are various types of controls based on your shop's process air requirements. Consult with a compressor distributor and select the compressor that is best suited for your needs and applications. Since distributors typically represent one manufacturer of compressors, it is advantageous to elicit proposals from several distributors. Also, consider consulting with an energy engineer who will make suggestions based upon what is best for your needs, not based upon the compressor that a distributor might represent.
- Aftercooler efficiency - as mechanical energy is applied during compression, temperature of a fluid (air) increases. Aftercoolers help to reduce the temperature of the air. As the temperature of the air is reduced and reaches its dew point, water vapor in the air is condensed, collected and drained from the system through a separator. An undersized aftercooler can create system problems due to inadequately tempered air and present operational concerns for your air consuming equipment.
There are two maintenance programs practiced in the industrial marketplace - reactive and preventive. Reactive maintenance, the practice of allowing equipment to operate until it fails before conducting any maintenance, is perhaps the most common maintenance practice. Manpower and budgetary requirements needed to manage a successful maintenance program are often shunned in favor of production requirements and scheduling. In reality, this is not a real maintenance practice; it's more like putting out fires.
Preventive maintenance uses scheduled production downtimes to perform maintenance recommended by the manufacturer of the equipment and is designed to get the maximum life out of the equipment. These maintenance practices typically include inspections, general cleaning, greasing and component testing.
Stay on Schedule
A final area to consider in the quest to conserve energy is a function of operations and plant scheduling. Demand costs in the Chicagoland area (ComEd territory) are typically only levied during peak times, typically 9:00 a.m. to 6:00 p.m. In addition, the cost of energy during peak hours can be more than two times that of off-peak energy. Scheduling any processes that use energy for nighttime hours will save significant money by shedding peak demand charges and using less expensive energy. If it is possible to perform power intensive processes during an off-peak shift, doing so will significantly reduce your energy costs.
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