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ENG 1102 Design Project - Energy Budgets Where is the energy going? What resources am I using?

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Agenda ● Review electrical, mechanical, and thermal energy calcs ● Introduce Energy Budgets and Applications ● Show an energy budget examples ● Begin planning and documenting an energy budget for your project

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Thermodynamics ● Energy may be converted from one type to another - however - ● Energy is conserved (i.e., it cannot be created or destroyed)

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Energy Sources/Resources Electrical – Power from Grid Chemical – Nat. Gas, Oil, Steam Mechanical – Human, Potential Sinks (Energy Consumers) Electrical – Pumps, Mill, Cooling, Gas Compression Thermal - Heaters Mechanical - Drag, Rolling Resistance Thermodynamics energy balance

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● Flowing electrons – Metals are conductors because they contain few loosely bound electrons in their outer shells – Electrons in the outer shells are free to jump from one atom to the next ● 1 Coulomb = x electrons (unit for counting electrons (C)) Reference: Eide, et.al, Engineering Fundamentals and Problem Solving, pg

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Electron Flow is Analogous to the Flow of Water in a pipe. Flow (gpm) Pump Valve Pressure (psi) Reservoir Current(amp) Battery Resistor Voltage (volt) Ground

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Electron Flow is Analogous to the Flow of Water in a pipe. No Flow Pump Closed Valve (max resistance) Max Pressure Reservoir No Current Battery Open Switch (max resistance) Max Voltage Ground

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Electron Flow is Analogous to the Flow of Water in a pipe. Flow (gpm) Pump Open Valve (full flow, min resistance) Pressure (psi) Reservoir Current(amp) Battery Closed Switch (min resistance, max flow, "short circuit") Voltage (volt) Ground

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Terminology ● Voltage (Volt, V) = potential difference, difference in energy per unit charge, measured with a voltmeter ● Current (Amp, A) = flowrate of electrons, charge per unit time (C/s), measured with an ammeter ● Resistance (Ohm, ) = opposition to flow of charge

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Electrical Power …(watts) Batteries are specified in terms of Voltage and Amp-Hours. How much Energy is in a Battery? What are the units?

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Motor Power Examples: – 3 Amps, 12 Volts P = 36 W – 50mA, 9.4V P = 470 mW – What's the Power? What are the units? Watt [=] J/sec

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As a Team The electric motor on a table saw runs on 240V circuit and draws a current of 4.8 amps. How much power does it use? – in watts (W)? – in horsepower (hp)? ● 1 hp = 746 W

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As a Team The electric motor on a table saw runs on 240V circuit and draws a current of 4.8 amps. How much power does it use? – in watts (W)? 1152 W – in horsepower (hp)? ● 1 hp = 746 W 1.544hp

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Electrical Power …(watts) How is it sold?

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Electrical Power …(watts) Approx $.12 per kwatt-hour

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Electrical Power ● What is Power (units?) – time rate of work or energy (V-amps, joules/sec or watts) ● How is it calculated – P = V*I = I 2 *R = V 2 /R ● How is Electrical Power (or Energy) bought and sold (units?) – kWhr

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Elevation Potential Energy … If you are peddling up a hill … What are the units?

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Thermal Power ● Heat to raise temperature of water ● Heat to evaporate water as it is held at high temps ● Other thermal power needed???

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Heat capacity (C p ) of water = 1 Btu/(lbm-deg F) Latent Heat of evap ( H v ) = 1000 Btu/lbm – When shifting phase (liquid to gas) H = H v Natural gas: – 1000 std ft^3 (scf) = 10^6 Btu – Typical unit of measure: therm=100,000 Btu – Approx cost = $1.05/therm Reference: Holtsapple, et.al, Foundations of Engineering, pg. 71 Felder & Rousseau, Elementary Principles in Chemical Processes pg. 365 Thermal Power

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Thermal Power Example You wish to heat a tank containing 100 lbm of water from 25°F to 50°F. How much energy is required (in BTU)? How many scf of Natural Gas will you need to purchase? - C p-H2O = 1 Btu/(lbm-°F) std ft^3 (scf) = 10^6 Btu

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Thermal Power Example Mass of Water = 100 lbm of water T = 25°F to 50°F = 25°F How much energy is required (in BTU)? How many scf of Natural Gas will you need to purchase? - C p-H2O = 1 Btu/(lbm-°F) std ft^3 (scf) = 10^6 Btu

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● Lance Armstrong: approx 500W over 1 hr – Approx. 1kW over 1 minute ● Bike Rider Guy/Gal: approx W over 1 hr – Approx. 400W over 1 minute Power = Energy/Time Reference: Wilson, et.al, Bicycle Science, pg. 44 Human Power

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Resource Budget: Accounting for Materials ● Tracks all inputs and outputs to your process (energy, raw materials, byproducts, products, etc.) ● Estimates energy and materials consumed in process ● Used to estimate annual costs/profits of company ● Used to identify opportunities for process improvement

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What is an Energy Budget? ● ????

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What is an Energy Budget? ● A means of planning the energy usage of a system ● A means of cost predictions and control ● An engineering tool to optimize the efficiency of any energy using system ● A “balance sheet” of energy sources and sinks

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What are the major energy consumers? (Sinks) Where does the energy come from? (Sources) Residential Homes and Commercial Buildings

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Configuration Diagram Brewery Where are… Sources? Sinks?

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Energy Budget - Brewing Purpose(s): – To estimate the energy cost for one batch of beer ● In a spreadsheet, list unit operations and estimate power requirement for the line and annual cost to operate line. ● Cite references and state your assumptions in your spreadsheet

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Energy Budget – Flood Control Purpose(s): - To estimate the energy cost for pumping station at “rest,” at full operation and expected annual use - Document assumptions in a spreadsheet that clearly shows units and calculations ● Cite references

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Example Energy Budget – Brewery (Flood will be similar, electrical)

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Energy Budget – HPV Purpose(s): - To estimate the HPV speed for a given set of conditions - Document assumptions in a spreadsheet that clearly shows units and calculations ● Cite references

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Material Budget ● Purpose(s): – (Brew) To complete a mass balance on a typical brewing line and calculate the input/output quantities – (Flood) To determine the amount (and type) of material used in constructing flood control system – AND…To determine the amount of time necessary to construct your flood control system (will it be ready for next hurricane season?) ● Can be completed in spreadsheet format. ● Cite references and state your assumptions

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Brewery Mass Balance 16 barrels ? ? ? ? ? ? ? ? ? ? ? ? General Process Info – What changes are you planning?

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Deliverable 6 - Resource Budget Due Week 10, Day 1 Summarize your Energy and Material Budgets / Mass Balance findings in a memo ● Discuss … how does this estimate compare with your design criteria? ● Suggest a way to significantly reduce energy usage. Refer to RFP for your project.

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