ANNEXURE

CHECKLIST & TIPS FOR ENERGY EFFICIENCY IN ELECTRICAL UTILITIES

Electricity 

• 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. 
• 
  Properly size to the load for optimum efficiency.

Motors

(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°C 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.

Bureau of Energy Efficiency                                   193

Use synthetic lubricants for large gearboxes. Eliminate eddy current couplings. 

• Shut them off when not needed.
• 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. 
• 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. 
• 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. 
  • 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.
  • 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. 

Fans

Blowers

Pumps

Compressors 

Compressed air

(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 5°C 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 oilwater 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.
• 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°C, results in a 20 – 25% decrease in compressor power consumption)
• Increase the evaporator temperature

Chillers 

(5.5°C 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 operating costs to serve 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 followup, then make a chiller efficiency-maintenance program a part of your continuous energy management program.
  • 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.