Prerna Kapila and Bhupinder Singh Dhillon
Cotton and woolen textiles comprise the most important part of textile industry of Ludhiana. Even though the place is world famous for its knitted products, the city has a thriving power loom industry with more than 200 power loom units of small to large sizes functioning in the cluster. In these units, handlooms, power looms and automatic machines are used simultaneously and producing various products ranging from high value pashmina shawls to low cost acrylic or polyester shawls, blankets, woven fabric for domestic as well as export purpose. The industry is also making silk stoles of exquisite quality, majority of which are exported all over the world. This sector has always been viewed as a major source of employment generation and rapid expansion of population has also helped in the growth of this sector as clothing continues to be a most basic requirement. The industry which was initially dependent on handlooms has gradually shifted towards power looms and specialized high speed looms thus increasing the energy requirement of the industry where initially it was all labour intensive work without any need of electricity.
There are many categories of textile units in the Ludhiana cluster, engaged in different processes related to the manufacture of knitwear products. The most energy–intensive units are those engaged in dyeing, processing and spinning. The printing units are relatively less energy intensive. Among all the units, energy cost forms the largest component of production expenses. The textile units in the Ludhiana cluster consume energy mainly in the forms of electricity for equipment and machineries as well as lighting, cooling and temperature control systems etc. Number of utilities involved in an industry depends upon the production capacity and process requirement of the industry. The saving potential in terms of energy depends on the resource utilization pattern of the industry. Numerous energy audits in textile units have displayed that 30 per cent of the savings in terms of rupees can be achieved in the plant by implementing the best practices in the process itself. Therefore together with the utilities, process should also be an area of concern.
Installation of meters for monitoring and energy savings
One of the best ways to track or monitor the various parameters involved within the utilities and processes is by installing meters at the generation and end usage points. This helps track the total generation and consumption of electricity at the process and equipment side. This also helps in operating the equipments at their best operating points and in preparing benchmarks. Installation of meters at key locations inside an industry enables the factory to closely track resources and energy consumption for specific purposes. This helps factory to focus on improving efficiency in resource intensive processes and to do proper costing of the products. Installing and operating accurate meters or software are the fundamental steps to benchmark performance and to enhance efficiency. It allows plants to identify and respond to leaks, detects unusual points in resource use and provides feedback on the effectiveness of measures that the industry undertakes to improve their processes. Meters and measurement software reinforce the benefits of efficiency increasing measures and encourage continuous improvement. Diesel generator is also an alternate source of electricity generation at the work station site. Special care needs to be given to this, as generation of electricity from DG sets is a costly affair. The main parameters which need to be taken care of are fuel consumption on hourly basis, frequency, kWh, ampere, voltage and measurement of the flue gas temperature.
Best Practices for saving energy in terms of electricity
Given the associated utilities, some improvements in industries require relatively large investments in equipment modernization. But there are certain initiatives which provide a particularly easy starting point for increasing manufacturing efficiency as compared to process optimization methods. Each opportunity identified should be evaluated in terms of initial investment required for improvement or replacements in the utilities, payback period and resources savings. Although individual leaks may not seem important in the overall consumption scenario, they can be responsible for a surprisingly significant loss of resources over the course of a year. Some best practices that can be identified and utilized for probable energy savings are
- Minimize blower inlet and outlet obstructions
- Clean screens and filters regularly.
- Minimize blower speed.
- Use low- slip or no- slip belts.
- Check belt tension regularly.
- Eliminate variable pitch pulleys.
- Use variable speed drives for large variable blower loads.
- Use energy- efficient motors for continuous or near- continuous operation.
- Eliminate ductwork leaks.
- Turn blowers off when not needed.
- Power factor improvement.
- Installation of separate transformers for lighting system.
- Balancing of phase-wise voltages, currents at motor/machine end terminals.
In industries it is observed that the power factor is maintained near to unity only at the main incomer side. The best way to improve power factor is by installing a correct capacity bank of capacitor at the motor or machine end terminal side so that exceed current can reduce at the motor end and ultimately reduce the overall power consumption.
Voltages between all three phases should be equal at the motor end terminal. Any unbalance in the phase voltage may lead to increase in the winding temperature of the phase and thus increase the current drawn at the terminal end. Though implementation of this best practice may provide small saving opportunities, however in terms of maintaining the operating efficiency and service life of the motor, steps to balance the voltage in all phases should be undertaken. As a general rule, 1 % imbalance in voltage causes 7 % imbalance in current and approximately 5 % increase in motor losses.
For proper work execution, adequate lighting should be available so that there is proper visibility which permits healthy observation of the product. In general practice in most of the industries, tube lights with fixtures are used at work stations and high wattage lamps are used for peripheral lightings. The higher lux level can be reduced to a suitable level by removing a fitting. Quality of light being received at the work station depends upon the reflection factor in the reflector used, it is better to replace complete fitting including fixtures in order to get proper and required lux level at the work place. Some tips for energy efficiency improvements in lighting system are
- Reduce excessive illumination levels to standard levels using delamping etc.
- Aggressively control lighting with clock timers, delay timers, photocells and occupancy sensors.
- Install efficient alternatives to incandescent lighting, mercury vapour lighting etc. such as low pressure sodium, high pressure sodium, metal halide, fluorescents, mercury vapour and incandescent.
- Select ballasts and lamps carefully with high power factor and long term efficiency in mind.
- Upgrade obsolete fluorescent systems to compact fluorescents and electronic ballasts.
- Consider downsizing the fixtures in order to prevent excessive usage.
- Consider painting the walls with a lighter colour.
- Use task lighting and reduce background illumination.
- Re-evaluate exterior lighting strategy, type and control.
- Change exit signs from incandescent to LED.
Apart from this, motor performance tests should be conducted wherever applicable so that motors operate at maximum efficiency without overloading or under loading. The industries should use energy efficient motors where economical and their alignment should be checked periodically. There should be proper ventilation and proper efficiency restoration must be there after rewinding.
Many units can take significant steps towards reducing wastes and costs by implementing small changes in good housekeeping which require little investment beyond improved management and attention to detail. Poor storage practices often lead to material being damaged or dirty resulting in making the industry give a discount on the same. It is a good practice to demarcate a special storage area in the work place, raise the floor level of storage areas and reduce leakages or breakage. Unclean work sites can lead to rework through contamination of textile products. Regular cleaning of workspace should be the responsibility of the staff at each work station. Adopting these quick opportunities help industries to develop a clean production mentality that can lead to substantial improvements and cost efficiencies.