Energy savings and conservation measures
by Hafsa Raiz-Lecturer, National Textile University, Faisalabad

Energy sector plays a vital role for the economic development, particularly in the manufacturing sector. World primary energy demand will continue to rise at about 2% annually, over the next twenty five years, driven by economic growth.

Total World consumption of marketed energy is expected to grow by 57% over the span between 2004 to 2030 period. Total world energy use will rise from 447 quadrillion British thermal units (Btu) in 2004 to 559 quadrillion Btu in 2015 and then to 702 quadrillion Btu till 2030.(Fig :1)

Developing countries, especially in Asia, are expected to account for the largest share of the growth in world energy demand. SAARC Energy Center (SEC) established at Islamabad in March 2006.The 1st Meeting of the Governing Board of the SEC was held in November 2006 in Islamabad. One of the objectives of this center is to find energy saving measures in SAARC. Pakistan ranks 33rd in terms of world energy consumption in (2004). Pakistan‘s primary energy supplies for the year 2006-2007 reaches to 60.4 million tones of oil equivalent (TOE).  Oil and gas from the bulk of primary commercial energy supply mix, contributing 79.0% (oil:30.0%, gas:48.5%, LPG:0.5%). The other sources include; Coal:7.3%, hydro electricity: 12.6% and nuclear and imported electricity:10%.

The major consumption of energy in the Pakistan at present is industrial, transport, domestic, agriculture and others. (Fig:2)

In today’s changing scenario, Pakistan greatly suffered due to crisis of energy. The continuous price rise in petroleum and the widening gap in demand and supply of electricity in Pakistan, has  made it imperative to look for efficient use of energy and renewable energy to ensure economic, effective and un-interruptive power supply to the manufacturing units to enhance productivity. Energy efficiency and renewable energy leads to be Sustainable Energy policy. At present in Pakistan Wind and Solar energies should be considered as clean and low cost renewable resources.

Energy efficiency is a key component of any organization to reduce environmental impact, and increase competitiveness through reduction of energy costs. High electricity consumption and steam consumption leads to increased cost for factory and ultimately cost for the entire country. Spinning and weaving processes consume a large amount of electricity while wet processing consumes a considerable amount of steam amounting to quite a considerable part of operating cost of the factory. This effects the increase in the energy demand and could be translated as increased country’s expenses. It is particularly important that energy conservation technologies and techniques, should be disseminated to governments, engineers and operators at plant level.

National Productivity Organization (NPO) is striving to attain maximum efficiency in proper utilization of existing energy with the help of suitable energy saving measures in the SME sector that contributes a major portion towards economic growth. 

NPO has taken an initiative in December 2005 and signed the agreement with GTZ(German technical cooperation) to launch energy audits in textile sector under Renewable Energy & Energy Efficiency framework to enhance productivity and quality.  In textile industry appreciable amount of energy can be saved by regulating the temperature in steam in pipes, installing heat exchangers etc. This program was initiated in July 2006. In this regard, energy audit was conducted in six units under the supervision of German experts. Spinning  and  processing industries were audited  in the first phase. Weaving industries and composite industrial units will be audited in the next phase.10-15% energy saving is achieved through audits in the first phase. The results of energy audit conducted in six pilot projects (two each at Lahore, Faisalabad and Karachi) of textile sector (spinning & processing) selected with the assistance and cooperation of APTMA. The outcome of the energy audits is very impressive.  By implementing the suggested measures, average 10% of the energy saving potentials in spinning units and 25-30% in processing units has been identified. Now, NPO in association with APTAMA is preparing a program for providing financial support to  the industry so that measures can be taken for energy saving as suggested by energy audits.

In general, energy in textile industry is mostly used in the form of electricity as power source for machines, lighting, office equipments etc, oil/coal as a fuel for boilers, gas for power generation.

Energy audit is a key to systematic approach for decision making in energy management. Energy audit indicates potential for improvement, areas where major portion of any management effort should be concentrated.

In energy audit, the following eight steps should be followed:

v     Data Gathering.

v     Utility analysis.

v     Inventory and review of equipment performance.

v     Measurements and monitoring.

v     Identification of  potential energy conservation measures.

v     Analysis of saving potentials.

v     Financial analysis.

v     Reporting.

Major energy consuming areas/equipment

v     Boiler.

v     Steam distribution networks.

v     Compressed air networks.

v     Electric motors.

v     Lighting.

v     Air-conditioning.

v     Pumps and blowers.

The general measures of energy saving in the textile sector are as follows:

v     Transfer of energy: At first, check the inefficient transfer of energy by any visible abnormal symptoms in running equipment by using the second law of Thermodynamics. During smooth transfer of energy there is no abnormal heat generation, spark etc. whereas in other cases, sparks produced due to loose joints, heating produced in motors due to metal to metal friction, sound produced due to vibration or metal to metal friction.

v     Company wide training is also a part of energy management,  relevant to a wide range of departments within a company. Awareness program on energy saving methods is   necessary for the operators. Achievement of  the EC goals through company wide efforts are possible and coordination among workers groups should made similar to QC. Workers should be trained about resource conservations and  the staff should be proactive.

v     Insulation of Hot surfaces: Steam loses due to heat radiation from steam transportation pipes and pressure drops are maximum. All the steam pipes and hot equipments should be insulated.

v     Reuse of steam condensates: Steam condensate is a hot water stream which can be used for boiler feed water and in processing. Proper insulated storage tanks should be made for this purpose.

v     Upkeep of steam traps: Steam trap are important in steam distribution system. Proper maintenance of steam traps is necessary, so that leakage of steam and condensate can be avoided.

v     Installation of economizer on boiler: Flue gases (thermal energy) should be recovered and reused.

v     Measurement of boiler efficiency: Regular monitoring of boiler performance is needed to maintain high efficiency. Flow meter should be installed to measure its consumption.

v     Installation of water softening  plant: In boilers, scale formation occurs if feed water is ground hard water, so thermal energy is lost by excessive blow downs. Water softening plant should be installed. Water softening plants are  also required for air conditioning plants.

v     Selection of fuel: In selecting fuels, those with good flue characteristics in addition to high calorific value and ease of combustion are required.

v     Compressor: Screw type compressor is more energy efficient.

v     Pressure Gauges: It is recommended to instal pressure gauges at all lines to monitor pressure.

v     Air leakage:The pipeline system, handling compressed air should not have air leakage .Air leakage points should be identified and rectified to avoid energy losses.

v     Filters: Filters should be properly maintained, so that compressor ensures more efficient compression.

v     Electric motors: Normally, process machinery is supplied with electricity. Electric motors consume more than 90% of the electricity. Many new machines have multiple motors with a control board that controls the movement of each motor. Energy efficient motors should be used, because they have high efficiency and operating speeds. They save about 4% energy.

v     Ventilation: Brings down the motor body temperature for better efficiency by good ventilation.

v     Maintenance: Periodic maintenance schedule.

v     Power factor: Power factor improvement should be taken into account for energy saving.

v     Rewound motor: Rewound motors should be avoided, it reduce energy efficiency.

v     Old equipment: Old motors should be replaced.

v     Frequency Convertor: Machines operating at variable loads, frequency convertor should be placed on motors

v     EEL system: The share of lightening system in energy consumption is high and only one percent increase in lighting level can  increase human productivity by 6%.Energy efficient lighting system should be used.

v     Right light: Choose the right light.

v     Cleaning: Clean walls and ceiling to improve reflectivity. Regular cleaning schedule should be established to minimize energy losses.

v     Mounting Heights: Light mounting height should be reduced, it effects illumination level.

v     Non-working hours: Turn off lights when not in use. Provide lighting only where and when required.

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v     Inefficient lights: Replace existing inefficient lights with efficient lights. Improve switching arrangements

v     Day light: Try to use daylight, where possible.

v     Air conditioning: Air conditioning helps process working. Air conditioning plants should be examined to determine efficiency of operation.

v     Maintenance: Routine maintenance schedule should be adhered to.

v     Ducts: Avoid sharp bends in ducts for smooth flow inside premises.

v     Fans: Replace fixed fans used for supply and return air with variable fans, so air flow can adjusted according to seasonal requirement. At high flow, motors consume more energy.

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v     Water audit: Textile industry uses large amount of water in processes. A measure to save energy is to reduce use of water and effective dewatering of the fabric before drying. Drying of wet fabric consumes more energy.

v     Instruments: Sophisticated instruments like digital air velocity meter, Lux meter,  Flue gas analyze, Data loggers, etc are required for measuring the actual situation of energy use.

Some measures of conservation of energy are mentioned above. The initial cost of the implementation of these measures may be high, but payback period and subsequent savings may prove beneficial in the long run. The aim of these measures is to ensure that the running of the existing equipment is at its maximum possible efficiency, thus leading to energy conservation and efficient utilization of other resources.

References

v     By Muhammad Asghar, “APTAMA‘s initiative to conserve energy” Dawn 19 March 2008.

v     By Ijaz Kakakhel, “Pakistan looking at an alternate source of energy “Daily Times 21,December 2007.

v     Mukhtar Ahmed Advisor to the Prime Minister of Pakistan on Energy (Pakistan’s Energy Strategy and its role in South Asia).

v     Pakistan Energy Yearbook, 2007.

v     Best  Practices Reports SMEDA.

v     vBy Muhammad Mushtaq Ahmad “Energy conservation and cost saving“September 1998.

v     Zafer Javed ,HOD Garment Manufacturing Technology, NTU.

v     S.Ashok,Coimbotore, India. “Energy saving  and audit in textile industry”.u