Air audit identifies air leakage across departments and inefficient usage as major factors behind high energy consumption.
Patspin India Ltd is part of the GTN Group, a fast growing textile company that started operations in 1966 in Aluva in the outskirts of Kochi, Kerala. Patspin, set up in Udumalpet in Tamil Nadu in 1994, has grown into a large operation with a total spindle capacity of 62,400.
The factory manufactures yarns of different counts from Ne 24s to Ne 200s. It employs a range of traditional methods and new-age technologies and processes to manufacture innovative products such as WonderTwist that combines the benefits of doubled gassed and compact yarns, and Infiniti, the GTN Group’s brand of compact yarn. It also produces several ring spun products such as high twist yarn, reverse twist yarn and gassed yarn.
The Patspin plant has four air compressors and two air dryers that are used for a variety of spinning processes. The plant operates 8,496 hours a year (354 days x 24 hours) and pays Rs 7 per unit towards power. The plant’s compressed air system consumes 188 kWh at 1007 cfm and incurs an annual power bill of Rs 112 lakh.
An air audit conducted at the plant highlighted a range of measures to reduce energy consumption without cutting down on production targets or affecting the production schedule. The air audit identified potential annual energy savings of a total of Rs 49 lakh.
The importance of an air audit
The energy efficiency of air compressor systems tends to reduce over time. To retain optimum efficiency, users need to monitor their performance and power usage, and conduct regular maintenance. Energy can be saved by changing the type of compressors being used, modifying the line design, arresting leaks and optimising usage.
Air audits help identify specific problem areas in the air compressor system and provide users a comprehensive report on what they need to do to reduce energy usage. ELGi has been conducting air audits for not only companies that use ELGi products but also those using other compressor brands. Since 2011, when ELGi started conducting air audits, it has completed over 250 air audits and proposed savings worth Rs 62.51 crore. For the textile industry alone, ELGi has conducted around 135 air audits.
The audit team uses flow meters, power analysers, water flow meters, digital pressure gauges, anemometers, infrared thermometers and condition monitoring equipment to evaluate an operation’s air usage. Following the analysis, the team submits a report with a summary of potential savings, along with recommended changes and associated costs. Some common problems the team sees are incorrect compressor size, inadequate air distribution system, incorrect positioning of downstream accessories and air receivers, and poor regulation of pressure.
Savings potential identified
In an air audit conducted at Patspin Ltd, ELGi recommended a range of measures to optimise the use of the available resources with an aim to reducing energy consumption. Before making these recommendations, the team studied the plant’s existing compressed air system. It measured the amount of compressed air being generated and supplied, the distribution demand and the actual requirement.
Patspin needed to make a one-time investment of Rs 30 lakh to realise this benefit. ELGi estimated that the company would recover the investment made in just seven months.
Of the measure recommended, the most significant was air leakage control. During investigation, the ELGi team measured a total of 450 cfm at 6.5 bar g of air leakage. Though leakage was rampant across departments and processes, the team found that the reason for leakage was improper handling of equipment by end users and not faults in the air pipelines. After the audit findings, ELGi conducted training for Patspin’s team to educate them on ways to optimise energy use.
The recommendations also included ways to further improve the performance of the plant’s compressors. ELGi proposed the installation of hot air ducting to reduce the ambient temperature in the compressor room and immediately fixing the problem of oil carryover to reduce air pressure in downstream accessories.