Consulting-Specifying Engineer - August 2007 - (Page A11)

Adding engine-driven compression to existing electric-drive air plants reduces electric energy and demand charges, and allows operators to take advantage of time-of-day electric rates, while having ample air compression capability around the clock. Further, it allows owners to make energy choices based on actual energy market conditions. natural gas-ﬁred packages in sizes from 75 hp to 280 hp, using either Cummins or GM natural gas engines driving screw compressors. MATCH SYSTEM TO INDUSTRY NEEDS Alternatively, the compressor system may be custom engineered, as with Ingersoll Rand. Steve Stiemsma of Ingersoll Rand says his ﬁrm will design a system based on the speciﬁc characteristics of the industrial load. He indicates, “We work with customers to determine the operating pressure of their existing systems and the speciﬁc volumes of air needed. Then we assemble compressors and engine sets to meet those needs.” AVAILABLE FROM MANY MANUFACTURERS Manufacturers including Ingersoll Rand, GrimmerSchmidt, Scales Air Compressor and Energen Technologies offer such engine-driven air compressor systems. According to Pete Grimmer from GrimmerSchmidt, there recently has been a signiﬁcant growth of interest in natural gas-powered air compressors. Grimmer notes, “Interest in natural gasdriven compressors has really picked up in the last six months. It may have to do with rapidly rising electric demand charges in many markets. If so, this could be a longer-term trend.” Uses for compressed air in manufacturing and processing industries include blast-cleaning, painting, product handling, packaging equipment and releasing plastic products from blow-molds. Systems may range from 25 hp to 500 hp. Grimmer says larger industrial users of compressed air typically use multiple compressors. This creates an opportunity for combination plants, allowing operators choices of whether to prioritize electric or natural gas equipment, depending on prevailing energy rates and system load requirements. Natural gas-ﬁred engines such as these Waukesha engines are ideally suited for industrial applications including air compression, pumping, fans, chillers and refrigeration. valuable in the food processing industry, where there is a large requirement for hot water for sanitation and cleanup. COMFORT COOLING AND REFRIGERATION Another application for stationary natural gas engines in industry is to operate water chillers for process or comfort cooling or for process refrigeration. Again, by removing a major electrical load from the plant service, demand charges and electric energy charges can be dramatically reduced, and reliance on the electric grid is reduced. Manufacturers such as York and Tecogen offer packaged engine-driven chillers, and Tecogen’s TecoFROST™ refrigeration system is widely used in the food processing industry. Units are available for both conventional refrigerants and ammonia systems. In addition to reduced electric demand and energy charges, these systems eliminate the needs for costly electric service upgrades, and will operate at high efﬁciency over a wide range of loads. As with all engine-driven systems, these chillers and refrigeration systems have high potential for engine heat recovery for hot water generation. Byproduct heat comes both from the engine cooling water and from heat exchangers on the unit exhaust, and can produce a signiﬁcant volume of hot water in the range of 200°F to 250°F. This feature is especially DESIGNED FOR CONTINUOUS DUTY Engine-driven chillers and refrigeration systems feature advanced microprocessor controls to allow full system protection and unattended operation. These engines are designed for continuous service with long required service intervals. Because they use natural gas, engine emissions are low. Engine-driven systems are widely used for replacement of existing electric driven cooling capacity, or to supplement an existing system. A combination or hybrid cooling plant of both electric and gas engine powered chillers gives the operator choices in energy type, and provides a measure of independence from outages on the central station electric service. PUMPS AND BLOWERS Natural gas-ﬁred engines also are an interesting option for operation of pumps or blowers in industrial operations. As with the other applications, their attractiveness comes from avoidance of electric demands and energy charges, and their ability to deliver high torque both at part and full load. Engine-driven pumps are particularly popular in the petrochemical industries, for manufacturing operations requiring large volumes of STANDARD PACKAGES OR CUSTOM DESIGNS Industrial air compressors may be centrifugal, screw or reciprocating. All can be operated by natural-gas ﬁred engines. The systems may be standard manufactured packages, as is the case of the GrimmerSchmidt, Scales and Energen engine-driven air compressor lines. GrimmerSchmidt, for example, offers A11

Table of Contents Feed for the Digital Edition of Consulting-Specifying Engineer - August 2007

Contents M/E Roundtable Giants 100 Pullout Poster Giants Stand Tall: CSE Giants 100 Report Electrical Design for Tall Buildings HVAC and Fire Safety for Elevator Systems How to Beat the Codes GAS Technology Supplement Recovering Waste Heat from Boilers New Applications for Tankless Water Heating Systmes Techniques Improve for Powder Coating MDF New Tools Available for Heat Treating Steel Direct Drive Engines

Consulting-Specifying Engineer - August 2007

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