Tips for Energy Conservation for Industries

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
  • Burn wastes if
  • Insulate exposed heated oil
  • Clean burners, nozzles, strainers,
  • Inspect oil heaters for proper oil
  • Close burner air and/or stack dampers when the burner is off to minimize heat loss up the
  • 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
  • Use boiler blowdown to help warm the back-up
  • Optimize deaerator
  • Inspect door
  • Inspect for scale and sediment on the waterside

(A 1 mm thick scale (deposit) on the waterside could increase fuel consumption by 5 to 8%).

  • Inspect for soot, fly ash, and slag on the fireside

(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
  • Add an economizer to preheat boiler feedwater using exhaust
  • Recycle steam
  • Study part-load characteristics and cycling costs to determine the most-efficient mode for operating multiple
  • Consider multiple or modular boiler units instead of one or two large
  • 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

Steam System

  • Fix steam leaks and condensate leaks

(A 3 mm diameter hole on a pipeline carrying 7 kg/cm2 steam would waste 33-kilo liters of fuel oil per year).

  • Accumulate work orders for the 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
  • Use backpressure steam turbines to produce lower steam
  • Use more efficient steam desuperheating
  • Ensure process temperatures are correctly
  • Maintain lowest acceptable process steam
  • Reduce hot water wastage to
  • Remove or blank off all redundant steam
  • Ensure condensate is returned or re-used in the process

(6 0C raise in feed water temperature by economizer/condensate recovery corresponds to a 1% saving in fuel consumption, in boiler).

  • Preheat boiler feed-water.
  • Recover boiler
  • Check operation of steam
  • 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
  • Consider recovery of vent steam (e.g. — on large flash tanks).
  • Use waste steam for water
  • Use an absorption chiller to condense exhaust steam before returning the condensate to the
  • 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

Furnaces

  • Check against infiltration of air: Use doors or air
  • Monitor O2 /CO2/CO and control excess air to the optimum
  • Improve burner design, combustion control and
  • Ensure that the furnace combustion chamber is under slight positive
  • Use ceramic fibers in the case of batch
  • Match the load to the furnace
  • Retrofit with heat recovery
  • Investigate cycle times and
  • Provide temperature
  • Ensure that flame does not touch the

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 liters furnace oil in a year.)

  • Insulate any hot or cold metal or
  • Replace wet
  • Use an infrared gun to check for cold wall areas during cold weather or hot-wall areas during hot
  • 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,
  • Recover heat from incinerator off-gas.
  • Use waste heat for fuel oil heating, boiler feedwater heating, outside air heating,
  • Use chiller waste heat to preheat hot
  • Use heat
  • Use absorption
  • Use thermal wheels, run-around systems, heat pipe systems, and air-to-air exchangers.

ELECTRICAL UTILITIES

Electricity Distribution System

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

Motors

  • Properly size to the load for optimum

(High-efficiency motors offer 4 – 5% higher efficiency than standard motors)

  • Use energy-efficient motors where
  • Use synchronous motors to improve the power factor.
  • Check
  • Provide proper ventilation

(For every 10 oC increase in motor operating temperature over the recommended peak, the motor life is estimated to be halved)

  • Check for under-voltage and over-voltage
  • Balance the three-phase power

(An imbalanced voltage can reduce 3 – 5% in motor input power)

  • Demand efficiency restoration after motor

(If rewinding is not done properly, the efficiency can be reduced by 5 – 8%)

Drives

  • Use variable-speed drives for large variable
  • Use high-efficiency gear
  • Use precision
  • Check belt tension
  • Eliminate variable-pitch
  • Use flat belts as alternatives to v-belts.
  • Use synthetic lubricants for large
  • Eliminate eddy current
  • Shut them off when not

Fans

  • Use smooth, well-rounded air inlet cones for fan air
  • Avoid poor flow distribution at the fan
  • Minimize fan inlet and outlet
  • Clean screens, filters, and fan blades
  • Use aerofoil-shaped fan
  • Minimize fan
  • Use low-slip or flat
  • Check belt tension
  • Eliminate variable pitch
  • Use variable speed drives for large variable fan
  • Use energy-efficient motors for continuous or near-continuous operation
  • Eliminate leaks in
  • Minimize bends in ductwork
  • Turn fans off when not

Blowers

  • Use smooth, well-rounded air inlet ducts or cones for air intakes.
  • Minimize blower inlet and outlet
  • Clean screens and filters
  • Minimize blower
  • Use low-slip or no-slip
  • Check belt tension
  • Eliminate variable pitch
  • Use variable speed drives for large variable blower
  • Use energy-efficient motors for continuous or near-continuous
  • Eliminate ductwork
  • Turn blowers off when they are not

Pumps

  • Operate pumping near the best efficiency
  • Modify pumping to minimize
  • Adapt to wide load variation with variable speed drives or sequenced control of smaller
  • Stop running both pumps — add an auto-start for an online spare or add a booster pump in the problem
  • Use booster pumps for small loads requiring higher
  • Increase fluid temperature differentials to reduce pumping
  • Repair seals and packing to minimize water
  • Balance the system to minimize flows and reduce pump power
  • Use siphon effect to advantage: don’t waste pumping head with a free-fall (gravity) return.

Compressors

  • Consider variable speed drive for the variable load on positive displacement
  • Use a synthetic lubricant if the compressor manufacturer permits
  • Be sure lubricating oil temperature is not too high (oil degradation and lowered viscosity) and not too low (condensation contamination).
  • Change the oil filter
  • Periodically inspect compressor intercoolers for proper
  • Use waste heat from a very large compressor to power an absorption chiller or preheat process or utility
  • 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

Compressed air

  • Install a control system to coordinate multiple breaths of air
  • Study part-load characteristics and cycling costs to determine the most efficient mode for operating multiple breaths of air
  • Avoid oversizing — match the connected
  • Load up modulation-controlled air compressors. (They use almost as much power at partial load as at full )
  • Turn off the backup air compressor until it is
  • 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
  • Turn off refrigerated and heated air dryers when the air compressors are
  • Use a control system to minimize heatless desiccant dryer
  • 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
  • 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
  • Use a small air compressor when a major production load is
  • Take air compressor intake air from the coolest (but not air-conditioned) location. (Every 50C reduction in intake air temperature would result in a 1% reduction in compressor power consumption)
  • Use an air-cooled aftercooler to heat building makeup air in
  • Be sure that heat exchangers are not fouled (e.g. — with oil).
  • Be sure that air/oil separators are not
  • Monitor pressure drops across suction and discharge filters and clean or replace filters promptly upon
  • Use a properly sized compressed air storage receiver. Minimize disposal costs by using a lubricant that is fully deductible and an effective oil-water
  • 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
  • Use nozzles or venturi-type devices rather than blowing with open compressed airlines.
  • Check for leaking drain valves on compressed air filter/regulator sets. Certain rubber-type valves may leak continuously after they age and
  • In dusty environments, control packaging lines with high-intensity photocell units instead of standard units with continuous air purging of lenses and
  • 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

Chillers

  • Increase the chilled water temperature setpoint if
  • Use the lowest temperature condenser water available that the chiller can

(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

(1 mm scale build-up on condenser tubes can increase energy consumption by 40%)

  • Optimize condenser water flow rate and refrigerated water flow
  • Replace old chillers or compressors with new higher-efficiency
  • Use water-cooled rather than air-cooled chiller
  • Use energy-efficient motors for continuous or near-continuous
  • Specify appropriate fouling factors for
  • Do not overcharge
  • Install a control system to coordinate multiple
  • Study part-load characteristics and cycling costs to determine the most-efficient mode for operating multiple
  • Run the chillers with the lowest energy consumption. It saves energy cost, fuels a base
  • Avoid oversizing — match the connected
  • Isolate off-line chillers and cooling
  • 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

HVAC (Heating / Ventilation / Air Conditioning)

  • Tune-up the HVAC control
  • Consider installing a building automation system (BAS) or energy management system (EMS) or restoring an out-of-service
  • Balance the system to minimize flows and reduce blower/fan/pump power
  • Eliminate or reduce reheat whenever
  • Use appropriate HVAC thermostat
  • 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
  • In winter during unoccupied periods, allowing temperatures to fall as low as possible without freezing water lines or damaging stored
  • In summer during unoccupied periods, allowing temperatures to rise as high as possible without damaging stored
  • Improve control and utilization of outside
  • Use air-to-air heat exchangers to reduce energy requirements for heating and cooling of outside
  • Reduce HVAC system operating hours (e.g. — night, weekend).
  • Optimize
  • 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
  • Use evaporative cooling in dry
  • Reduce humidification or dehumidification during unoccupied
  • Use atomization rather than steam for humidification where
  • Clean HVAC unit coils periodically and comb mashed
  • Upgrade filter banks to reduce pressure drop and thus lower fan power
  • Check HVAC filters on a schedule (at least monthly) and clean/change if
  • 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
  • Install ceiling fans to minimize thermal stratification in high-bay
  • Relocate air diffusers to optimum heights in areas with high
  • Consider reducing ceiling
  • Eliminate obstructions in front of radiators, baseboard heaters,
  • Check reflectors on infrared heaters for cleanliness and proper beam
  • Use professionally-designed industrial ventilation hoods for dust and vapor
  • Use local infrared heat for personnel rather than heating the entire
  • 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
  • Put HVAC window units on a timer
  • Don’t oversize cooling units. (Oversized units will “short-cycle” which results in poor humidity )
  • Install multi-fueling capability and run with the cheapest fuel available at the
  • Consider dedicated make-up air for exhaust hoods. (Why exhaust the air conditioning or heat if you don’t need to?)
  • Minimize HVAC fan
  • Consider desiccant drying of outside air to reduce cooling requirements in humid climates.
  • Consider ground source heat
  • Seal leaky HVAC
  • Seal all leaks around
  • Repair loose or damaged flexible connections (including those under air handling units).
  • Eliminate simultaneous heating and cooling during the seasonal transition
  • Zone HVAC air and water systems to minimize energy
  • Inspect, clean, lubricate, and adjust damper blades and
  • 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

Refrigeration

  • Use water-cooled condensers rather than air-cooled
  • Challenge the need for refrigeration, particularly for old batch processes.
  • Avoid oversizing — match the connected
  • Consider gas-powered refrigeration equipment to minimize electrical demand
  • Use “free cooling” to allow chiller shutdown in cold
  • Use refrigerated water loads in series if
  • Convert firewater or other tanks to thermal
  • Don’t assume that the old way is still the best — particularly for energy-intensive low temperature
  • Correct inappropriate brine or glycol concentration that adversely affects heat transfer and/or pumping

If it sweats, insulate it, but if it is corroding, replace it first.

  • Make adjustments to minimize hot gas bypass
  • Inspect moisture/liquid
  • Consider a change of refrigerant type if it will improve
  • Check for correct refrigerant charge
  • Inspect the purge for air and water
  • 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

Cooling towers

  • Control cooling tower fans based on leaving water
  • Control to the optimum water temperature as determined from the cooling tower and chiller performance
  • 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
  • Turn off unnecessary cooling tower fans when loads are
  • Cover hot water basins (to minimize algae growth that contributes to fouling).
  • Balance flow to cooling tower hot water
  • Periodically clean plugged cooling tower water distribution
  • Install new nozzles to obtain a more uniform water
  • Replace splash bars with self-extinguishing PVC cellular-film
  • On old counterflow cooling towers, replace old spray-type nozzles with new square- spray ABS practically-non-clogging
  • Replace slat-type drift eliminators with high-efficiency, low-pressure-drop, self-extinguishing, PVC cellular
  • If possible, follow the manufacturer’s recommended clearances around cooling towers and relocate or modify structures, signs, fences, dumpsters, etc. that interfere with air intake or
  • Optimize cooling tower fan blade angle on a seasonal and/or load
  • Correct excessive and/or uneven fan blade tip clearance and poor fan
  • Use a velocity pressure recovery fan ring.
  • Divert clean air-conditioned building exhaust to the cooling tower during hot
  • Re-line leaking cooling tower cold water
  • Check water overflow pipes for proper operating
  • Optimize chemical
  • Consider side stream water
  • Restrict flows through large loads to design
  • Shut offloads that are not in
  • Take blowdown water from the return water
  • Optimize blowdown flow rate.
  • Automate blowdown to minimize
  • 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 )
  • Implement a cooling tower winterization plan to minimize ice build-up.
  • Install interlocks to prevent fan operation when there is no water
  • 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

Lighting

  • Reduce excessive illumination levels to standard levels using switching, damping, etc. (Know the electrical effects before doing decamping.)
  • Aggressively control lighting with clock timers, delay timers, photocells, and/or occupancy
  • 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,
  • Consider painting the walls a lighter color and using less lighting fixtures or lower wattages.
  • Use task lighting and reduce background
  • Re-evaluate exterior lighting strategy, type, and control. Control it
  • Change exit signs from incandescent to

DG sets

  • Optimize loading
  • Use waste heat to generate steam/hot water /power an absorption chiller or preheat process or utility
  • 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,gaskets, weatherstripping,
  • Consider new thermal doors, thermal windows, roofing insulation,
  • Install windbreaks near exterior
  • Replace single-pane glass with insulating
  • Consider covering some window and skylight areas with insulated wall panels inside the
  • If visibility is not required but the light is required, consider replacing exterior windows with insulated glass
  • Consider tinted glass, reflective glass, coatings, awnings, overhangs, draperies, blinds, and shades for sunlit exterior
  • Use landscaping to
  • Add vestibules or revolving doors to primary exterior personnel
  • Consider automatic doors, air curtains, strip doors, etc. at high-traffic passages between conditioned and non-conditioned spaces. Use self-closing doors if
  • Use intermediate doors in stairways and vertical passages to minimize the building stack effect.
  • Use dock seals at shipping and receiving
  • Bring cleaning personnel in during the working day or as soon after as possible to minimize lighting and HVAC

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
  • Eliminate once-through cooling with
  • Use the least expensive type of water that will satisfy the
  • Fix water
  • Test for underground water leaks. (It’s easy to do over a holiday )
  • Check water overflow pipes for proper operating
  • Automate blowdown to minimize
  • Provide proper tools for wash down — especially self-closing
  • Install efficient
  • Reduce flows at water sampling
  • Eliminate continuous overflow at water
  • Promptly repair leaking toilets and
  • Use water restrictors on faucets, showers,
  • Use self-closing type faucets in
  • Use the lowest possible hot water
  • 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
  • Consider the installation of a thermal solar system for warm
  • If water must be heated electrically, consider accumulation in a large insulated storage tank to minimize heating at on-peak electric
  • Use multiple, distributed, small water heaters to minimize thermal losses in a large piping
  • Use freeze protection valves rather than manual bleeding of
  • Consider leased and mobile water treatment systems, especially for deionized
  • Seal sumps to prevent seepage inward from necessitating extra sump pump operation.
  • Install pretreatment to reduce TOC and BOD
  • 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
  • Shut down spare, idling, or unneeded
  • Make sure that all of the utilities to redundant areas are turned off — including utilities like compressed air and cooling
  • Install automatic control to efficiently coordinate multiple air compressors, chillers, cooling tower cells, boilers,
  • Renegotiate utility contracts to reflect current loads and
  • Consider buying utilities from neighbors, particularly to handle
  • Leased space often has low-bid inefficient equipment. Consider upgrades if your lease will continue for several more
  • Adjust fluid temperatures within acceptable limits to minimize undesirable heat transfer in long
  • Minimize use of flow bypasses and minimize bypass flow
  • Provide restriction orifices in purges (nitrogen, steam, ).
  • Eliminate unnecessary flow measurement
  • Consider alternatives to high-pressure drops across
  • Turn off winter heat tracing that is on in

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