Energy Saving Tips for Industries Consumers

Tips for Energy Conservation for Industries
THERMAL UTILITIES

Boilers
  • Preheat combustion air with waste heat
    (22 0C reduction in flue gas temperature increases boiler efficiency by 1%).
  • Use variable speed drives on large boiler combustion air fans with variable flows.
  • Burn wastes if permitted.
  • Insulate exposed heated oil tanks.
  • Clean burners, nozzles, strainers, etc.
  • Inspect oil heaters for proper oil temperature.
  • Close burner air and/or stack dampers when the burner is off to minimize heat loss
    up the stack.
  • Improve oxygen trim control (e.g. -- limit excess air to less than 10% on clean fuels).
    (5% reduction in excess air increases boiler efficiency by 1% or: 1% reduction of
    residual oxygen in stack gas increases boiler efficiency by 1%.)
  • Automate/optimize boiler blowdown. Recover boiler blowdown heat.
  • Use boiler blowdown to help warm the back-up boiler.
  • Optimize deaerator venting.
  • Inspect door gaskets.
  • Inspect for scale and sediment on the water side
    (A 1 mm thick scale (deposit) on the water side could increase fuel consumption by 5 to 8%).

  • Inspect for soot, flyash, and slag on the fire side
    (A 3 mm thick soot deposition on the heat transfer surface can cause an increase in fuel consumption to the tune of 2.5%.)
  • Optimize boiler water treatment.
  • Add an economizer to preheat boiler feedwater using exhaust heat.
  • Recycle steam condensate.
  • Study part-load characteristics and cycling costs to determine the most-efficient
    mode for operating multiple boilers.
  • Consider multiple or modular boiler units instead of one or two large boilers.
  • Establish a boiler efficiency-maintenance program. Start with an energy audit and
    follow-up, then make a boiler efficiency-maintenance program a part of your continuous energy management program.

    Steam System
    • Fix steam leaks and condensate leaks
      (A 3 mm diameter hole on a pipe line carrying 7 kg/cm2 steam would waste 33 kilo litres of fuel oil per year).
    • Accumulate work orders for repair of steam leaks that can't be fixed during the heating season due to system shutdown requirements. Tag each such leak with a durable tag with a good description.
    • Use back pressure steam turbines to produce lower steam pressures.
    • Use more-efficient steam desuperheating methods.
    • Ensure process temperatures are correctly controlled.
    • Maintain lowest acceptable process steam pressures.
      Reduce hot water wastage to drain
  • Remove or blank off all redundant steam piping.
  • Ensure condensate is returned or re-used in the process
    (6 0C raise in feed water temperature by economiser/condensate recovery
    corresponds to a 1% saving in fuel consumption, in boiler).
  • Preheat boiler feed-water.
  • Recover boiler blowdown.
  • Check operation of steam traps.
  • Remove air from indirect steam using equipment
    (0.25 mm thick air film offers the same resistance to heat transfer as a 330 mm thick
    copper wall.)
  • Inspect steam traps regularly and repair malfunctioning traps promptly.
  • Consider recovery of vent steam (e.g. -- on large flash tanks).
  • Use waste steam for water heating.
  • Use an absorption chiller to condense exhaust steam before returning the
    condensate to the boiler.
  • Use electric pumps instead of steam ejectors when cost benefits permit
  • Establish a steam efficiency-maintenance program. Start with an energy audit and
    follow-up, then make a steam efficiency-maintenance program a part of your continuous energy management program. 

Furnaces
  • Check against infiltration of air: Use doors or air curtains.
  • Monitor O2 /CO2/CO and control excess air to the optimum level.
  • Improve burner design, combustion control and instrumentation.
  • Ensure that the furnace combustion chamber is under slight
    positive pressure.
  • Use ceramic fibres in the case of batch operations.
  • Match the load to the furnace capacity.
  • Retrofit with heat recovery device.
  • Investigate cycle times and reduce.
  • Provide temperature controllers.
  • Ensure that flame does not touch the stock.
    Insulation
  • Repair damaged insulation
    (A bare steam pipe of 150 mm diameter and 100 m length, carrying saturated steam at 8 kg/cm2 would waste 25,000 litres furnace oil in a year.)
  • Insulate any hot or cold metal or insulation.
  • Replace wet insulation.
  • Use an infrared gun to check for cold wall areas during cold
    weather or hot wall areas during hot weather.
  • Ensure that all insulated surfaces are cladded with aluminum
  • Insulate all flanges, valves and couplings
  • Insulate open tanks
    (70% heat losses can be reduced by floating a layer of 45 mm diameter polypropylene (plastic) balls on the surface of 90 0C hot liquid/condensate).

Waste heat recovery
  • Recover heat from flue gas, engine cooling water, engine exhaust, low pressure waste steam, drying oven exhaust, boiler blowdown, etc.
  • Recover heat from incinerator off-gas.
  • Use waste heat for fuel oil heating, boiler feedwater heating,
    outside air heating, etc.
  • Use chiller waste heat to preheat hot water.
  • Use heat pumps.
  • Use absorption refrigeration.
  • Use thermal wheels, run-around systems, heat pipe systems, and air-to-air
    exchangers.


    ELECTRICAL UTILITIES

    Electricity Distribution System

    • Optimise the tariff structure with utility supplier
    • Schedule your operations to maintain a high load factor
    • Shift loads to off-peak times if possible.
    • Minimise maximum demand by tripping loads through a demand
      controller
    • Stagger start-up times for equipment with large starting currents to
      minimize load peaking.
    • Use standby electric generation equipment for on-peak high load periods.
    • Correct power factor to at least 0.90 under rated load conditions.
    • Relocate transformers close to main loads.
    • Set transformer taps to optimum settings.
    • Disconnect primary power to transformers that do not serve any active loads
    • Consider on-site electric generation or cogeneration.
    • Export power to grid if you have any surplus in your captive generation
    • Check utility electric meter with your own meter.
    • Shut off unnecessary computers, printers, and copiers at night.

      Motors
      • Properly size to the load for optimum efficiency.
        (High efficiency motors offer of 4 - 5% higher efficiency than standard motors)
      • Use energy-efficient motors where economical.
      • Use synchronous motors to improve power factor.
      • Check alignment.
      • Provide proper ventilation
        (For every 10 oC increase in motor operating temperature over recommended peak,
        the motor life is estimated to be halved)
      • Check for under-voltage and over-voltage conditions.
      • Balance the three-phase power supply.
        (An imbalanced voltage can reduce 3 - 5% in motor input power)
      • Demand efficiency restoration after motor rewinding.
        (If rewinding is not done properly, the efficiency can be reduced by 5 - 8%)


Drives
  • Use variable-speed drives for large variable loads.
  • Use high-efficiency gear sets.
  • Use precision alignment.
  • Check belt tension regularly.
  • Eliminate variable-pitch pulleys.
  • Use flat belts as alternatives to v-belts.
  • Use synthetic lubricants for large gearboxes.
  • Eliminate eddy current couplings.
  • Shut them off when not needed.
    Fans
  • Use smooth, well-rounded air inlet cones for fan air intakes.
  • Avoid poor flow distribution at the fan inlet.
  • Minimize fan inlet and outlet obstructions.
  • Clean screens, filters, and fan blades regularly.
  • Use aerofoil-shaped fan blades.
  • Minimize fan speed.
  • Use low-slip or flat belts.
  • Check belt tension regularly.
  • Eliminate variable pitch pulleys.
  • Use variable speed drives for large variable fan loads.
  • Use energy-efficient motors for continuous or near-continuous operation
  • Eliminate leaks in ductwork.
  • Minimise bends in ductwork
  • Turn fans off when not needed.
    Blowers
  • Use smooth, well-rounded air inlet ducts or cones for air intakes.
  • 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 they are not needed.
    Pumps
  • Operate pumping near best efficiency point.
  • Modify pumping to minimize throttling.
  • Adapt to wide load variation with variable speed drives or
    sequenced control of smaller units.
  • Stop running both pumps -- add an auto-start for an on-line
    spare or add a booster pump in the problem area.
  • Use booster pumps for small loads requiring higher pressures.
  • Increase fluid temperature differentials to reduce pumping rates.
  • Repair seals and packing to minimize water waste.
  • Balance the system to minimize flows and reduce pump power requirements.
Use siphon effect to advantage: don't waste pumping head with a free-fall (gravity) return.

Compressors
  • Consider variable speed drive for variable load on positive displacement compressors.
  • Use a synthetic lubricant if the compressor manufacturer permits it.
  • Be sure lubricating oil temperature is not too high (oil degradation and lowered viscosity) and not too low (condensation
    contamination).
  • Change the oil filter regularly.
  • Periodically inspect compressor intercoolers for proper functioning.
  • Use waste heat from a very large compressor to power an absorption chiller or
    preheat process or utility feeds.
  • Establish a compressor efficiency-maintenance program. Start with an energy audit
    and follow-up, then make a compressor efficiency-maintenance program a part of your continuous energy management program.

    Compressed air

  • Install a control system to coordinate multiple air compressors.
  • Study part-load characteristics and cycling costs to determine
    the most-efficient mode for operating multiple air compressors.
  • Avoid over sizing -- match the connected load.
  • Load up modulation-controlled air compressors. (They use
    almost as much power at partial load as at full load.)
  • Turn off the back-up air compressor until it is needed.
  • Reduce air compressor discharge pressure to the lowest acceptable setting.
    (Reduction of 1 kg/cm2 air pressure (8 kg/cm2 to 7 kg/cm2) would result in 9% input
    power savings. This will also reduce compressed air leakage rates by 10%)
  • Use the highest reasonable dryer dew point settings.
  • Turn off refrigerated and heated air dryers when the air compressors are off.
  • Use a control system to minimize heatless desiccant dryer purging.
  • Minimize purges, leaks, excessive pressure drops, and condensation accumulation.
    (Compressed air leak from 1 mm hole size at 7 kg/cm2 pressure would mean power
    loss equivalent to 0.5 kW)
  • Use drain controls instead of continuous air bleeds through the drains.
  • Consider engine-driven or steam-driven air compression to reduce electrical demand
    charges.
  • Replace standard v-belts with high-efficiency flat belts as the old v-belts wear out.
  • Use a small air compressor when major production load is off.
  • Take air compressor intake air from the coolest (but not air conditioned) location.
    (Every 50C reduction in intake air temperature would result in 1% reduction in
    compressor power consumption)
  • Use an air-cooled aftercooler to heat building makeup air in winter.
  • Be sure that heat exchangers are not fouled (e.g. -- with oil).
  • Be sure that air/oil separators are not fouled.
  • Monitor pressure drops across suction and discharge filters and clean or replace
    filters promptly upon alarm.
  • Use a properly sized compressed air storage receiver. Minimize disposal costs by
    using lubricant that is fully demulsible and an effective oil-water separator.
  • Consider alternatives to compressed air such as blowers for cooling, hydraulic rather than air cylinders, electric rather than air actuators, and electronic rather than pneumatic controls.
  • Use nozzles or venturi-type devices rather than blowing with open compressed air lines.
  • Check for leaking drain valves on compressed air filter/regulator sets. Certain rubber- type valves may leak continuously after they age and crack.
  • In dusty environments, control packaging lines with high-intensity photocell units instead of standard units with continuous air purging of lenses and reflectors.
  • Establish a compressed air efficiency-maintenance program. Start with an energy audit and follow-up, then make a compressed air efficiency-maintenance program a part of your continuous energy management program.

    Chillers
  • Increase the chilled water temperature set point if possible.
  • Use the lowest temperature condenser water available that
    the chiller can handle.
    (Reducing condensing temperature by 5.5 0C, results in a 20 -
    25% decrease in compressor power consumption)
  • Increase the evaporator temperature
    (5.50C increase in evaporator temperature reduces compressor power consumption by 20 - 25%)
  • Clean heat exchangers when fouled.
    (1 mm scale build-up on condenser tubes can increase energy consumption by 40%)
  • Optimize condenser water flow rate and refrigerated water flow rate.
  • Replace old chillers or compressors with new higher-efficiency models.
  • Use water-cooled rather than air-cooled chiller condensers.
  • Use energy-efficient motors for continuous or near-continuous operation.
  • Specify appropriate fouling factors for condensers.
  • Do not overcharge oil.
  • Install a control system to coordinate multiple chillers.
  • Study part-load characteristics and cycling costs to determine the most-efficient
    mode for operating multiple chillers.
  • Run the chillers with the lowest energy consumption. It saves energy cost, fuels a
    base load.
  • Avoid oversizing -- match the connected load.
  • Isolate off-line chillers and cooling towers.
  • Establish a chiller efficiency-maintenance program. Start with an energy audit and
    follow-up, then make a chiller efficiency-maintenance program a part of your continuous energy management program.

    HVAC (Heating / Ventilation / Air Conditioning)
    • Tune up the HVAC control system.
    • Consider installing a building automation system (BAS) or energy
      management system (EMS) or restoring an out-of-service one.
    • Balance the system to minimize flows and reduce blower/fan/pump
      power requirements.
    • Eliminate or reduce reheat whenever possible.
    • Use appropriate HVAC thermostat setback.
    • Use morning pre-cooling in summer and pre-heating in winter (i.e. -- before electrical
      peak hours).
    • Use building thermal lag to minimize HVAC equipment operating time.
  • In winter during unoccupied periods, allow temperatures to fall as low as possible without freezing water lines or damaging stored materials.
  • In summer during unoccupied periods, allow temperatures to rise as high as possible without damaging stored materials.
  • Improve control and utilization of outside air.
  • Use air-to-air heat exchangers to reduce energy requirements for heating and cooling
    of outside air.
  • Reduce HVAC system operating hours (e.g. -- night, weekend).
  • Optimize ventilation.
  • Ventilate only when necessary. To allow some areas to be shut down when
    unoccupied, install dedicated HVAC systems on continuous loads (e.g. -- computer
    rooms).
  • Provide dedicated outside air supply to kitchens, cleaning rooms, combustion
    equipment, etc. to avoid excessive exhausting of conditioned air.
  • Use evaporative cooling in dry climates.
  • Reduce humidification or dehumidification during unoccupied periods.
  • Use atomization rather than steam for humidification where possible.
  • Clean HVAC unit coils periodically and comb mashed fins.
  • Upgrade filter banks to reduce pressure drop and thus lower fan power requirements.
  • Check HVAC filters on a schedule (at least monthly) and clean/change if appropriate.
  • Check pneumatic controls air compressors for proper operation, cycling, and
    maintenance.
  • Isolate air conditioned loading dock areas and cool storage areas using high-speed
    doors or clear PVC strip curtains.
  • Install ceiling fans to minimize thermal stratification in high-bay areas.
  • Relocate air diffusers to optimum heights in areas with high ceilings.
  • Consider reducing ceiling heights.
  • Eliminate obstructions in front of radiators, baseboard heaters, etc.
  • Check reflectors on infrared heaters for cleanliness and proper beam direction.
  • Use professionally-designed industrial ventilation hoods for dust and vapor control.
  • Use local infrared heat for personnel rather than heating the entire area.
  • Use spot cooling and heating (e.g. -- use ceiling fans for personnel rather than
    cooling the entire area).
  • Purchase only high-efficiency models for HVAC window units.
  • Put HVAC window units on timer control.
  • Don't oversize cooling units. (Oversized units will "short cycle" which results in poor
    humidity control.)
  • Install multi-fueling capability and run with the cheapest fuel available at the time.
  • Consider dedicated make-up air for exhaust hoods. (Why exhaust the air conditioning
    or heat if you don't need to?)
  • Minimize HVAC fan speeds.
  • Consider desiccant drying of outside air to reduce cooling requirements in humid
    climates.
  • Consider ground source heat pumps.
  • Seal leaky HVAC ductwork.
  • Seal all leaks around coils.
  • Repair loose or damaged flexible connections (including those under air handling
    units).
  • Eliminate simultaneous heating and cooling during seasonal transition periods.
  • Zone HVAC air and water systems to minimize energy use.
  • Inspect, clean, lubricate, and adjust damper blades and linkages.
Establish an HVAC efficiency-maintenance program. Start with an energy audit and follow-up, then make an HVAC efficiency-maintenance program a part of your continuous energy management program.

Refrigeration
  • Use water-cooled condensers rather than air-cooled condensers.
  • Challenge the need for refrigeration, particularly for old batch
    processes.
  • Avoid oversizing -- match the connected load.
  • Consider gas-powered refrigeration equipment to minimize electrical
    demand charges.
  • Use "free cooling" to allow chiller shutdown in cold weather.
  • Use refrigerated water loads in series if possible.
  • Convert firewater or other tanks to thermal storage.
  • Don't assume that the old way is still the best -- particularly for energy-intensive low
    temperature systems.
  • Correct inappropriate brine or glycol concentration that adversely affects heat
    transfer and/or pumping energy.
    If it sweats, insulate it, but if it is corroding, replace it first.
  • Make adjustments to minimize hot gas bypass operation.
  • Inspect moisture/liquid indicators.
  • Consider change of refrigerant type if it will improve efficiency.
  • Check for correct refrigerant charge level.
  • Inspect the purge for air and water leaks.
  • Establish a refrigeration efficiency-maintenance program. Start with an energy audit
    and follow-up, then make a refrigeration efficiency-maintenance program a part of your continuous energy management program.
    Cooling towers
  • Control cooling tower fans based on leaving water temperatures.
  • Control to the optimum water temperature as determined from
    cooling tower and chiller performance data.
  • Use two-speed or variable-speed drives for cooling tower fan
    control if the fans are few. Stage the cooling tower fans with on-off
    control if there are many.
  • Turn off unnecessary cooling tower fans when loads are reduced.
  • Cover hot water basins (to minimize algae growth that contributes to fouling).
  • Balance flow to cooling tower hot water basins.
  • Periodically clean plugged cooling tower water distribution nozzles.
  • Install new nozzles to obtain a more-uniform water pattern.
  • Replace splash bars with self-extinguishing PVC cellular-film fill.
  • On old counterflow cooling towers, replace old spray-type nozzles with new square-
    spray ABS practically-non-clogging nozzles.
  • Replace slat-type drift eliminators with high-efficiency, low-pressure-drop, self-
    extinguishing, PVC cellular units.
  • If possible, follow manufacturer's recommended clearances around cooling towers
    and relocate or modify structures, signs, fences, dumpsters, etc. that interfere with air
    intake or exhaust.
  • Optimize cooling tower fan blade angle on a seasonal and/or load basis.
  • Correct excessive and/or uneven fan blade tip clearance and poor fan balance.
  • Use a velocity pressure recovery fan ring.
  • Divert clean air-conditioned building exhaust to the cooling tower during hot weather.
  • Re-line leaking cooling tower cold water basins.
  • Check water overflow pipes for proper operating level.
  • Optimize chemical use.
  • Consider side stream water treatment.
  • Restrict flows through large loads to design values.
  • Shut off loads that are not in service.
  • Take blowdown water from the return water header.
  • Optimize blowdown flow rate.
  • Automate blowdown to minimize it.
  • Send blowdown to other uses (Remember, the blowdown does not have to be
    removed at the cooling tower. It can be removed anywhere in the piping system.)
  • Implement a cooling tower winterization plan to minimize ice build-up.
  • Install interlocks to prevent fan operation when there is no water flow.
  • Establish a cooling tower efficiency-maintenance program. Start with an energy audit
    and follow-up, then make a cooling tower efficiency-maintenance program a part of your continuous energy management program.

    Lighting
  • Reduce excessive illumination levels to standard levels using switching, delamping, etc. (Know the electrical effects before doing delamping.)
  • Aggressively control lighting with clock timers, delay timers, photocells, and/or occupancy sensors.
  • Install efficient alternatives to incandescent lighting, mercury vapor
    lighting, etc. Efficacy (lumens/watt) of various technologies range from best to worst approximately as follows: low pressure sodium, high pressure sodium, metal halide, fluorescent, mercury vapor, 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 daylighting, skylights, etc.
  • Consider painting the walls a lighter color and using less lighting fixtures or lower
    wattages.
  • Use task lighting and reduce background illumination.
  • Re-evaluate exterior lighting strategy, type, and control. Control it aggressively.
  • Change exit signs from incandescent to LED.
    DG sets
  • Optimise loading
  • Use waste heat to generate steam/hot water /power an absorption
    chiller or preheat process or utility feeds.
  • Use jacket and head cooling water for process needs
  • Clean air filters regularly
  • Insulate exhaust pipes to reduce DG set room temperatures
  • Use cheaper heavy fuel oil for capacities more than 1MW

Buildings
  • Seal exterior cracks/openings/gaps with caulk, gasketing, weatherstripping, etc.
  • Consider new thermal doors, thermal windows, roofing insulation, etc.
  • Install windbreaks near exterior doors.
  • Replace single-pane glass with insulating glass.
  • Consider covering some window and skylight areas with insulated wall
    panels inside the building.
  • If visibility is not required but light is required, consider replacing exterior windows
    with insulated glass block.
  • Consider tinted glass, reflective glass, coatings, awnings, overhangs, draperies,
    blinds, and shades for sunlit exterior windows.
  • Use landscaping to advantage.
  • Add vestibules or revolving doors to primary exterior personnel doors.
  • Consider automatic doors, air curtains, strip doors, etc. at high-traffic passages
    between conditioned and non-conditioned spaces. Use self-closing doors if possible.
  • Use intermediate doors in stairways and vertical passages to minimize building stack
    effect.
  • Use dock seals at shipping and receiving doors.
  • Bring cleaning personnel in during the working day or as soon after as possible to
    minimize lighting and HVAC costs.

    Water & Wastewater
  • Recycle water, particularly for uses with less-critical quality requirements.
  • Recycle water, especially if sewer costs are based on water consumption.
  • Balance closed systems to minimize flows and reduce pump power requirements.
  • Eliminate once-through cooling with water.
  • Use the least expensive type of water that will satisfy the requirement.
  • Fix water leaks.
  • Test for underground water leaks. (It's easy to do over a holiday shutdown.)
  • Check water overflow pipes for proper operating level.
  • Automate blowdown to minimize it.
  • Provide proper tools for wash down -- especially self-closing nozzles.
  • Install efficient irrigation.
  • Reduce flows at water sampling stations.
  • Eliminate continuous overflow at water tanks.
  • Promptly repair leaking toilets and faucets.
  • Use water restrictors on faucets, showers, etc.
  • Use self-closing type faucets in restrooms.
  • Use the lowest possible hot water temperature.
  • Do not use a central heating system hot water boiler to provide service hot water
    during the cooling season -- install a smaller, more-efficient system for the cooling
    season service hot water.
  • Consider the installation of a thermal solar system for warm water.
  • If water must be heated electrically, consider accumulation in a large insulated
    storage tank to minimize heating at on-peak electric rates.
  • Use multiple, distributed, small water heaters to minimize thermal losses in large
    piping systems.
  • Use freeze protection valves rather than manual bleeding of lines.

  • Consider leased and mobile water treatment systems, especially for deionized water.
  • Seal sumps to prevent seepage inward from necessitating extra sump pump
    operation.
  • Install pretreatment to reduce TOC and BOD surcharges.
  • Verify the water meter readings. (You'd be amazed how long a meter reading can be
    estimated after the meter breaks or the meter pit fills with water!)
  • Verify the sewer flows if the sewer bills are based on them

    Miscellaneous
  • Meter any unmetered utilities. Know what is normal efficient use. Track down causes of deviations.
  • Shut down spare, idling, or unneeded equipment.
  • Make sure that all of the utilities to redundant areas are turned off -- including utilities
    like compressed air and cooling water.
  • Install automatic control to efficiently coordinate multiple air compressors, chillers,
    cooling tower cells, boilers, etc.
  • Renegotiate utilities contracts to reflect current loads and variations.
  • Consider buying utilities from neighbors, particularly to handle peaks.
  • Leased space often has low-bid inefficient equipment. Consider upgrades if your
    lease will continue for several more years.
  • Adjust fluid temperatures within acceptable limits to minimize undesirable heat
    transfer in long pipelines.
  • Minimize use of flow bypasses and minimize bypass flow rates.
  • Provide restriction orifices in purges (nitrogen, steam, etc.).
  • Eliminate unnecessary flow measurement orifices.
  • Consider alternatives to high pressure drops across valves.
  • Turn off winter heat tracing that is on in summer.
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page11image16752(Source: Bureau of Energy Efficiency, New Delhi)


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