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ATEM MODULE 4: ELECTRICAL

ATEM MODULE 4: ELECTRICAL. Accredited Texas Energy Manager. Mechanical Systems. Why Should You Begin One? How Do You Begin One?. The Goal…. TO LOWER YOUR ELECTRIC BILL. Accredited Texas Energy Manager. Electricity is a Form of Energy. Three Basic Components of Electricity Voltage

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ATEM MODULE 4: ELECTRICAL

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  1. ATEM MODULE 4: ELECTRICAL Accredited Texas Energy Manager

  2. Mechanical Systems Why Should You Begin One? How Do You Begin One?

  3. The Goal… • TO LOWER YOUR ELECTRIC BILL Accredited Texas Energy Manager

  4. Electricity is a Form of Energy • Three Basic Components of Electricity • Voltage • Current • Resistance Accredited Texas Energy Manager

  5. To Simplify… Let’s look at the physical definition of work Work = Force X Distance Force Distance Accredited Texas Energy Manager

  6. Pipe=Wire What is Current? Current is flow of electric charge through a medium Units: Amps Accredited Texas Energy Manager

  7. Pipe=Wire What is Resistance? Resistance is the opposition to flow of electric current Units: Ohms Accredited Texas Energy Manager

  8. What Increases Resistance? • Type of materials used for wire • Aluminum is more resistive to current flow, than copper • The length of the wire • The longer the wire, the more resistance to current flow will be present • The cross-sectional area of the wire • The smaller the wire diameter, the more resistance to current flow will be present Pipe=Wire Accredited Texas Energy Manager

  9. Electrical Distribution Losses Accredited Texas Energy Manager

  10. Three Basic Components of Electricity • How are the three basic components related? Ohm’s Law Voltage = Current x Resistance V = I x R Accredited Texas Energy Manager

  11. Liquid = Electric Charges Pipe=Wire What is Voltage? The electric potential difference Distance The amount of work that can be done by moving an electric charge a distance Units: Watts Accredited Texas Energy Manager

  12. Liquid = Electric Charges Pipe=Wire What is Power? How quickly electrical energy is transferred Distance The amount of work that can be done by moving an electric charge a distance Units: Watts Accredited Texas Energy Manager

  13. Electrical Power • We learned: • Ohm’s Law - V = I x R Power = Voltage x Time Wh = V x Hours Where: Wh = Watt hours Note: 1000 Wh = 1 KiloWattHour (kWh) Accredited Texas Energy Manager

  14. Not All Power Is Useful • Total • Apparent Power • Units: Volt-Ampere • Not Useful • Reactive Power • Units: Volt-Ampere Reactive • Useful • Real Power • Units: Watts • Not ALL of the energy made was transferred to the right place Pipe=Wire Accredited Texas Energy Manager

  15. Non-Useable Power • Inductive loads have high reactive power • T12 Ballasts • Large Motors • Arc Welders • Inductive Furnace Accredited Texas Energy Manager

  16. How Are the Powers Related? (Apparent Power)2 = (Real Power)2 + (Reactive Power)2 • Apparent Power • Total Power delivered to the building from the electricity utility company • Units: Volt-Ampere or VA • Real Power • Power that you were able to use • Units: Watts or W • Reactive Power • Power that you wasted • Units: Volt-Ampere Reactive or VAr Accredited Texas Energy Manager

  17. How is Power Related to Voltage and Current? • Apparent Power ( • Total Power delivered to the building from the electricity utility company • Units: Volt-Ampere or VA Single Phase Three Phase Accredited Texas Energy Manager

  18. What is kWh? kWh = (Watts/1000) x Number of Hours • The energy consumed over a period of time (usually 1 hour) Accredited Texas Energy Manager

  19. Understanding kWh 2,000 Watt fan that runs for 7 hours =2kW x 7 hours = 14kWh Accredited Texas Energy Manager

  20. Back to the Electric Bill… Power Consumed Apparent Power the building required

  21. What is Power Factor? • Power Factor is the ratio of the real power to the total power (apparent power) Power Factor = • Power factor will range from 0 to 1 or 0% to 100% Real Power (Watts) Apparent Power (Volt-Amps) Accredited Texas Energy Manager

  22. Power Factor Example Real Power (Watts) Apparent Power (Volt-Amps) Power Factor = Real Power (Watts) 728 VA 0.97 = Real Power = 706 kW Accredited Texas Energy Manager

  23. Power Factor Correction • Power factor correction will only decrease your electric bill, if the utility imposes a penalty on power factor • Why? • Because most utility companies charge customers on an hourly average of Real Power (Watt) consumption Accredited Texas Energy Manager

  24. What is Load Factor? • Load factor is how much energy is used in comparison to the total peak energy available Load Factor = Load Factor = Load Factor = = = 50% Total kWh consumed per billing period Total potential energy available Total kWh consumer per billing period Peak Demand in kW x billing period x 24 hrs/day 36,000 kWh 100 kW x 30 days x 24 hrs/day 36,000 kWh 72,000 kWh Accredited Texas Energy Manager

  25. Understanding Load Factor • Both low and high load factors can represent energy cost saving opportunities • High LF may mean that you shaved the Peak Demand or reduced your monthly consumption • Low LF may mean that you reduced you operating hours, to save kWh but didn’t improve the Peak Demand General Rule If LF>50%, focus attention on excessive consumption If LF<50%, focus attention on Peak Demand reduction Accredited Texas Energy Manager

  26. Peak Demand (KW) • Electric meters count the amount of KW used in a time period • Typical time period is 15 minutes or 30 minutes • The largest consumption per time period is the Peak Demand • There can be a “ratcheted” annual peak demand, summer peak demand (4CP), and/or a monthly peak demand Accredited Texas Energy Manager

  27. Poor Peak Demand energy management program: fundamentals and development

  28. Peak Demand energy management program: fundamentals and development

  29. Demand Limiting • The practice of limiting or reducing the peak demand each day • Typically performed with a BAS system turning off extraneous equipment, or diverting non-essential usage to non-peak hours of the day (e.g. thermal storage) Accredited Texas Energy Manager

  30. Demand Limiting energy management program: fundamentals and development

  31. Demand Limiting Ideas • Don’t run heavy loads from 1 pm – 7 pm • Instead use them at night • Kilns, computer on wheels, dishwashers, dryers • Cycle needed equipment so the entire group does not run in the same time period • Groups of RTUs or Split Systems Accredited Texas Energy Manager

  32. Peak Demand of Water Cooled vs. Air Cooled Chillers energy management program: fundamentals and development

  33. What can I do to lower my peak kW demand, lower total consumption, increase the load factor, and lower my electric bill? Accredited Texas Energy Manager

  34. Add VFD’s • Variable Frequency Drive • Varies the incoming frequency, in order to change the motor speed and torque • Typically install 1 VFD per motor • A VFD can run a motor efficiently • It can also soft start motors and lower the peak kW demand Accredited Texas Energy Manager

  35. Savings Example • A 15 Horsepower motor can be reduced from 60 Hz to 45 Hz Fan Affinity Law: Where: HP = horsepower N = speed = = 6.38 = 57.8% Savings! If pump runs for 1800 hours/year ($0.10 electricity) saves $1,163/year Accredited Texas Energy Manager

  36. Adding VFD’s • Real World Example • Added VFD’s to two 50 HP motors and evaluated the cost savings • Saved in a year • 190,126 kWh from total consumption • 47 kW from the Peak Demand TOTAL OF: $18, 326.35 Accredited Texas Energy Manager

  37. Change Indoor Lighting • Change incandescent lamps to fluorescent or LED type to save energy Accredited Texas Energy Manager

  38. Change Indoor Lighting • Fluorescent – Change T12 fluorescent lamps to T8 or T5 lamps, and its corresponding ballast (starts and drives the lamps) 4 Foot Lamp T12 = 40W T8 = 32W T5 = 28W Example Small Building 200 2’ x 4’ Fixtures 4 Lamps each T12 vs T5? 32,000W vs 22,400 W 9,600W Comparable light output for less wattage of electricity Accredited Texas Energy Manager

  39. Change Indoor Lighting • So, what does it mean in $$$$$? 9,600W x 270 occupied days/year x 9.5 hours/day = 24,624 kWh 24,624 kWh x 0.085540/kWh = $2,106.33 savings a year Accredited Texas Energy Manager

  40. Change Indoor Lighting energy management program: fundamentals and development

  41. Change Outdoor Lighting to LED energy management program: fundamentals and development

  42. Add Lighting Controls • Occupancy Sensors • Lighting control relay panels energy management program: fundamentals and development

  43. DDC System Functions • Scheduling • Normal work days • Events • Weekends • Holidays • Control strategies • Optimum start & stop • Demand limiting • Temperature resets • Monitoring • Logging & trending • Diagnostics & troubleshooting • Alarming Accredited Texas Energy Manager

  44. DDC Protocols • BACNet • Open protocol • Developed by ASHRAE • Specifically for building equipment control • LONTalk • Proprietary protocol • Developed by Echelon Corp. • Special micro-compressor chip required for communication • Tridium (Niagra) • Proprietary built on open standards • Allows integration of diverse systems Accredited Texas Energy Manager

  45. Demand Control Ventilation • Utilize in area w/ high occupancy levels • Uses CO2 levels to estimate occupancy • Controls outside air flow w/ modulating dampers • Closed at zero occupancy (low CO2 level) • Full open at maximum occupancy (high CO2 level) Accredited Texas Energy Manager

  46. Utilizing Economizers • Supplies 100% outside air for cooling • Compressors do not operate • Takes advantage of mild outdoor conditions • Control types • Dry bulb • Less humid climates • Temperature only • Enthalpy • More humid climates • Temperature & humidity Accredited Texas Energy Manager

  47. Economizer Operation energy management program: fundamentals and development

  48. Setpoints • Occupied • Occupant comfort • Energy savings • Cooling costs rise 1.5% for each degree below 72º • Heating costs rise 1% for each degree above 68º • Unoccupied • Energy savings • Prevent building damage • Use instead of turning systems off Accredited Texas Energy Manager

  49. Control Strategies • Demand limiting • Demand limit setting • Loads shed when setting reached • Reduces peak demand & utility charges • Optimal startup • Heating or cooling started before occupied time • Setpoint reached at scheduled occupied time • Optimum stop • Heating or cooling setback while facilities occupied • Building allowed to “coast” Accredited Texas Energy Manager

  50. More Control Strategies • Supply air temperature reset • Based on return air or outside air temperature • Reduces amount of reheat during cooling • Chilled water temperature reset • Raise temperature of chilled water • Based on outdoor temperature & humidity • Caution not to raise temperature too much in humid conditions • Condenser water temperature reset • Decrease temperature of water leaving cooling tower • Increases chiller efficiency • Reduces chiller capacity Accredited Texas Energy Manager

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