Energy conservation in textile mills

Energy Conservation in textile mills needs to be given top priority now. The textile industry in Pakistan had stepped up a drive since 2009, to save electricity as 42 spinning mills, after their energy audit, are saving up to 10 percent power without any additional cost, with the technical inputs from GTZ, APO etc. Why is this mandatory process of Energy audit and conservation procedures not still practiced in India? Mill is worried about the pricing of yarn sale price but how much is lost thro power losses between cotton to yarn conversion pricing; and hence Energy auditing tool thro energy conservation measures, will catalyze and enhance the Operating profit margins of the mill.

The mill MD has taken the initiative to buy energy efficient equipments. THIS IS HALF DONE ONLY. If they give thrust to efficient running of the machines and focus on the invisible electricity losses in the daily routines, then definitely their operating profit margins can improve drastically.

So the Mill Management initiative is the first step towards energy management, first in the buying of EE equipments and it must not end there. The next step is more important now; that is continuously monitoring the equipments to sustain their energy consumption and operate at their safe and best optimized loading levels.

By energy conservation in the industry, we try to recover the losses which go as waste. By Energy Measurement, we draw a line between Avoidable and Unavoidable Losses and plan to minimize same. The industry manager finds it difficult to meet the ends, the cotton and yarn prices. But if he regulates and minimizes the power consumption of each machine he will be delighted to his margins are under his control and improves more.

Presently most of the mills have concentrated on Textile associated savings etc. Now if they concentrate more on Electrical Energy input to machines and their Mechanical Maintenance by Predictive and condition Monitoring, we can derive maximum productivity with minimum power losses and yarn wastages by Sustained and Regulated Energy Inputs to the machines.

Electric motors– Please concentrate on your motors up to 10 HP motor where you´re per hour recoverable loss is upto 2 KW per motor. These motors at 1 HP and above lose up to 35 % on efficiency where as above 10 HP motors lose around 15% Hence please Focus at the Pyramid Bottom and concentrate on the batch of small HP inefficient motors say on Pneumafill, short frame, OHT motors etc. Here the savings are more and payback is in months now.

The typical curve indicates the existing standard motor losses in the mill, the motor I2R losses gradually increases upto 75 % loading, hence efficiency is better upto 75 %. And after that the I2R loss slope steeply increases from 75 to 100 %. Hence the efficiency drops drastically nearing full load. The breakup of motor losses indicates that the losses are more now in full running of motor. To sustain motor efficiency for a decade, it is better to operate at part load based on vendor inputs of maximum sustained efficiency at what part loading.

We know now, that after a decade of running in closed hood with higher ambience of 45 *C, the motor de-rates to 96 % of the rated KW very shortly. So for the sustained efficiency to be achieved for many years in long ring frame motors, it is optimum to load at an average of 60 % loading, because of the ring frame application only and the accelerated ageing and de-rating factors.

In one of our energy audit in a mill, the long frame 55 KW @ 50 Hz rated motor consumes 54 KW at peak load when operated 60 Hz. So we had suggested them to go in for 75 KW motor. The inverter is used in long frame for flexible working and little saving. But the same inverter must not be utilized for setting at 60 Hz to increase spindle speed. Here the motor power loss is more due to overloading and increasing