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

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

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

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

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

● 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 = 6.24150636 x 10 18 electrons (unit for counting electrons (C)) Reference: Eide, et.al, Engineering Fundamentals and Problem Solving, pg. 349 - 360

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

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

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

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

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

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

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

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

Electrical Power …(watts)  How is it sold?

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

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

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

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

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

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) - 1000 std ft^3 (scf) = 10^6 Btu

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) - 1000 std ft^3 (scf) = 10^6 Btu

● Lance Armstrong: approx 500W over 1 hr – Approx. 1kW over 1 minute ● Bike Rider Guy/Gal: approx 100-200W over 1 hr – Approx. 400W over 1 minute Power = Energy/Time Reference: Wilson, et.al, Bicycle Science, pg. 44 Human Power

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

What is an Energy Budget? ● ????

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

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

Configuration Diagram Brewery Where are… Sources? Sinks?

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

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

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

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

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

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

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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