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Integrated Systems + Principles Approach. Manufacturing Energy End-Use Breakdown. Source: California Energy Commission (2000). Energy Systems. Lighting Motor drive Fluid flow Compressed air Steam and hot water Process heating Process cooling Heating, ventilating and air conditioning
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Manufacturing Energy End-Use Breakdown Source: California Energy Commission (2000)
Energy Systems • Lighting • Motor drive • Fluid flow • Compressed air • Steam and hot water • Process heating • Process cooling • Heating, ventilating and air conditioning • Cogeneration
Principles of Energy Efficiency • Inside Out Analysis • Understand Control Efficiency • Think Counter-flow • Avoid Mixing • Match Source Energy to End Use • Whole-system, Whole-time Frame Analysis
Integrated Systems + Principles Approach • Integrated systems + principles approach (ISPA) = Systems approach + Principles of energy efficiency • ISPA is both effective and thorough.
Inside-out: Amplifies Savings Reduce pipe friction: Savings = 1.00 kWh Pump 70% eff: Savings = 1.43 kWh Drive 95% eff: Savings = 1.50 kWh Motor 90% eff: Savings = 1.67 kWh T&D 91% eff: Savings = 1.83 kWh Powerplant 33% eff: Savings = 5.55 kWh
Inside-out: Reduces Costs • Original design: 95 hp in 14 pumps • Re-design: • Bigger pipes: Dp = c / d5 • (doubling d reduces Dp by 97%) • Layout pipes then equipment • shorter runs, fewer turns, valves, etc… • 7 hp in 2 pumps
Avoid Outside-in Thinking Traditional Analysis Sequence for Reducing Energy Use Traditional Analysis Sequence for Reducing Waste Result: Incremental improvement at high cost
Think from Inside Out! Inside-Out Analysis Sequence for Reducing Energy Use Inside-Out Analysis Sequence for Reducing Waste Result: Significant improvement at minimal cost
2. Understand Control Efficiency • Systems design for peak load, but operate at part-load • System efficiency generally changes at part load • Recognize and modify systems with poor part- load (control) efficiency
Air Compressor Control FP = FP0 + FC (1 – FP0)
3. Think Counter Flow • Heat transfer • Fluid flow
Counter-flow Improves Heat Exchange T Q Parallel Flow x T Q Counter Flow x
Stack Furnace Pre-heats Charge Reverb Furnace Stack Furnace
Counter-flow Within Zones Increases convection heat transfer by 83% Contact length = 2 x (5 + 4 + 3 + 2 + 1) = 30 feet Contact length = (10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1) = 55 feet
Tile Kiln (Counter flow?) Tile Exit Tile Entrance
Counter Flow Cooling Enables Cooling Tower Cross-flow cooling of extruded plastic uses 50 F water from chiller
4. Avoid Mixing • Availability analysis… Useful work destroyed with mixing • Examples • CAV/VAV air handlers • Separate hot and cold wells • Material reuse/recycling
HVAC Applications Cooling Energy Use Heating Energy Use
Cooling Applications Separate hot and cold water tanks
Utilize Current Daylighting Wright Brothers Factory, Dayton Ohio
Replace Colored / Fiberglass Windows with Corrugated Polycarbonate
Employ Skylighting Skylights: • Highest quality light • Reduce lighting energy costs • Increase heating/cooling costs
6. Whole System Whole Time Frame Design • Design heuristic derived from natural evolution • Nothing evolves in a vacuum, only as part of a system • No optimum tree, fan, … • Evolutionary perspective: ‘optimum’ synonymous with ‘perfectly integrated’ • Optimize whole system, not components • Design for whole time frame, next generation
Whole System Energy EngineeringOptimum Pipe Diameter • Dopt = 200 mm when Tot Cost = NPV(Energy)+Pipe • Dopt = 250 mm when Cost= NPV(Energy)+Pipe+Pump • Energy250 = Energy200 / 2
Whole System Accounting • Budgeting and capital processes separate from operational processes • Organizational structures within companies constrains optimum thinking • Enlarge system boundary to include entire company
Whole-Time Frame Accounting“Efficiency Gap” • “Numerous studies conclude 20% to 40% energy savings could be implemented cost effectively, but aren’t…..” • Discrepancy between economic and actual savings potential called “efficiency gap”. • Puzzled economists for decades: “I can’t believe they leave that much change lying on the table.”
Don’t Eat Your Seed Corn • SP = 2 years is ROR = 50% • SP = 10 years is ROR = 10%