~Energy
Energy Curriculum notes
8.2016
VOM meter: 2 lead VOM, e.g. Fluke Model 114
Measure ohms short and open
Measure ohms across chest (can calculate fatal voltage here if current is known)
Measure ohms around circle of students, break circuit (circuit concept here: need two wires)
Define "circuit"
Measure voltage across chest-why does it vary? (EKG concept, can extend to differential EKG)
Measure DC voltage of small batteries (learn what symbols for DC and AC voltage are on the meter)
Measure AC voltage at outlet (caution here)
Explain why dry hands are better, cross body shocks, grounding
Measure resistance from hands to ground
Electrical safety unit…
Kill-a-Watt unit
Ohmic loads: tea maker, coffee maker (make sure water is cool)
P=VI
P = I2R
Measure voltage at outlet
Measure resistance of ohmic load with VOM
Predict power used, current
Measure power, current (ohmic load)
Power measured/power calculated = ?
Repeat with vacuum cleaner or other motor device
Recalculate power calculated vs. measured
P = VI again, vs. power measured
Try the P.F. button
Light bulb analysis:
Incandescent bulb: measure R with VOM, measure power with KaW unit
CFL: repeat
LED: repeat
Next measure light output for each, compare with power used (measured with KaW unit)
Cost to run:
Calculate cost to use each bulb for 1 hour, define kWh.
Calculate cost to run tea maker for 1 hour, define kWh.
Calculate savings between LED, CFL and incandescent bulb, per day, week, month, year, over lifetime
Define ROI and TCO
Renewable energy:
ROI and TCO
PV, Wind and Solar thermal
ROI is time to pay off device (in days, months or years)
TCO is total cost of ownership (should be negative)
Data from websites or hands-on if available
Efficiency evaluation
PV panel
Measure incident solar radiation (or from weather service) in W/m2
Measure output of PV panel, using ohmic load (resistor or tea maker), current, voltage
Calculate % efficiency
Solar Thermal Panel
Solar thermal same incident solar, measure temp in and out for solar panel, and time to fill 1 liter container (flux)
Use mc∆t to calculate calories captured/harvested, 4.18j = 1 calorie, j/s = Watts
Wind turbine
Difficult with varying wind, you may be able to hold small turbines while driving a truck (this is how some are actually evaluated)
Area of turbine is needed, and wind speed, altitude (air density) as well
Look up Betz coefficient, 0.39 is max (why?)
May be done using data from manufacturers
Residential energy audits
TED units (theenergydetective.com)
Installed at houses, classrooms
Measures predicted billing, uses, trends
Excellent for articulating with commercial energy audits
Control by web units, using current transformers
CBW analog units process 8 analog 0-5Vdc inputs to web interface with logging
CTs are Hawkeye 922 units (0-5 Vdc output), with 30,60 and 120 Ampere rating
Larger ones as well
Assume PF = 1.00, calculate Watts from P = VI (assume voltage constant, but measure accurately to calibrate)
Energy Lab server
elab2.hpa.edu
Telemetry of campus or remote locations
Can interface with CBW units globally, as long as they have access to internet
Used in "energy hunts" finding lights or loads hidden around buildings
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