Over the last decade, electrical costs in the U.S. have grown at an unparalleled pace. The government has established energy conservation policies through the Compressed Air Challenge, which aim to reduce compressed air energy consumption 10% by 2010. To the facility manager, the cost of electrical power has become a principal deciding factor in the acquisition of capital equipment. In fact, energy consumption has a major influence on the bottom line of any plant in today's power-hungry economy. Many manufacturers of air compressors use a load/no-load control system that offers some advantages in the reduction of power consumed, typical is Kensun portable air compressors. With the rising cost of energy in mind, the search for a more efficient, energy-friendly method of control became a top priority with many manufacturers. Variable speed drive (VSD) compressor regulation systems are a response to this concern. VSD technology What does VSD do for an average compressor's energy consumption? To answer this question requires understanding the significance of energy consumption in the typical air compressor life-cycle cost of ownership. The initial cost of acquisition and installation is quite low when compared to the expense of electrical power (77% of total cost) to operate an air compressor for 5 yr when equipped with a standard compressor control system. There are dramatic savings found in typical applications by using a VSD equipped rotary compressor. Savings of 35% in electrical costs reduce the total life cycle cost by 22% over 5 yr. These savings take into account the slightly higher initial cost of the equipment itself. Energy consumption of an air compressor depends on the application and fluctuations that occur in the air system demand. To calculate the air system demand and cycles, measurement devices accurately determine actual system usage in a customer's application. Hundreds of measurements were taken in small and medium-sized industries. Each test interval was 1 wk. Three groups of typical air profiles emerged from these tests. Group profiles The first profile is typical for a plant working 24 hr/day with lower consumption during the night shift, higher consumption during the day shift, typical dip around lunch, and fixed, continuous consumption during the weekend. Fixed consumption could be minimum equipment running and leaks in the piping system. About 64% of all plants could be classified under Profile 1. The second profile represents a plant operating 5 days/week with only 2 shifts . There is no activity at night or on weekends. Air consumption fluctuates erratically. Profile 2 represents about 28% of all plants represented in the survey. The third profile is typical for an application with fixed air consumption 5 days/week (Fig. 5). This kind of application is not common in small and medium-sized plants and represents only 8% of all plants. Energy savings The energy savings realized by a VSD compressor compared to a standard compressor are shown in the table. Savings depend on the air demand profile. The weighted average, based on test data, results in a dramatic 35% energy savings. In addition, integrated VSD regulation achieves pressure stability. In tests, the VSD has maintained a constant discharge pressure within 1.5 psi of the set point. The typical pressure band of a compressor using standard controls is 10 psi or greater. The VSD's narrow pressure band allows a lower pressure in the piping system. The resulting savings can be dramatic, because every 6-psi reduction in delivery pressure cuts power consumption 3%. Not only is the ability to accurately maintain system pressure achieved, discharge pressure with the VSD is stable at any setting from 60-175 psig. This factor provides future flexibility without the need to purchase new compressed air equipment due to changing plant equipment requirements. Key concepts Traditional load/no-load systems do not save as much energy as variable speed drive regulation. The greatest energy savings are achieved by plants running three shifts. Variable speed drive regulation can achieve discharge pressure stability within 1.5 psi of set point.
0 Comments
Leave a Reply. |
AuthorI'm Bruce O. Pratt, who thoroughly enjoys researching about Power & Hand Tools. I hope my reviews can help you to choose the right products fit with your needs. Archives
November 2017
Categories |