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Teachers' Guide: Unit Conversions
Download the Annotated Version of the Conversions worksheet
(doc, 32 KB)
- Using the energy consumption values from the two "greenhouse gas emissions and energy consumption" tables
(from Part I and Part II of the "Getting Started" lesson) and the two worksheets provided, calculate the total
energy use of the house in common units (millions of BTUs/year) for the results in Parts I and Part II. Calculate total
carbon dioxide (CO2) emissions from the house for the results in Parts I and II. Show how
the units should be cancelled in the formulas.
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Based on your results from the Worksheets in the previous question, do the carbon dioxide emissions found in Parts I and II decline
from the results by the same percentage as the total energy use? If not, why would this be?
- Teacher Tools: Different forms of energy (gas, oil, etc.) have different emissions factors per useful unit of energy (BTU).
Thus, carbon dioxide emissions will decline more for a unit of oil saved than for a unit of natural gas saved, etc.
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Do the emissions calculated on the worksheets agree with those on from the Home Energy Saver? (Yes/No). If not, why might this be?
- Teacher Tools: Assumptions for electricity emissions factors (based on mix of fossil fuels) are different in the HES model
than the value given in the worksheet.
Energy Unit Conversions Worksheet: A
Complete this worksheet with the information found in Part I (base home), showing how the units cancel to yield the proper
final units. Note: The home you are modeling will probably not have all four types of energy shown below! Just skip the ones that
are not relevant.
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1. Convert raw energy to common units (millions of BTUs, MBTU): |
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a. _______________ kWh x 3413 BTU/kWh x 1 MBTU/1,000,000 BTU |
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= _______________ (fill in value and units) of electricity |
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b. _______________ Therms x 100,000 BTU/therm x 1 MBTU/1,000,000 BTU |
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= _______________ (fill in value and units) of natural gas |
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c. _______________ Gallons Oil x 138,095 BTU/gallon x 1 MBTU/1,000,000 BTU |
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= _______________ (fill in value and units) of heating oil |
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d. _______________ Gallons LPG x 95,500 BTUs/gallon x 1 MBTU/1,000,000 BTU |
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= _______________ (fill in value and units) of heating oil |
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e. _______________ combine the preceding results to get total energy from all sources |
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2. Convert MBTU of energy to greenhouse-gas emissions (pounds of carbon dioxide, CO2) |
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a. 1.2 lbs CO2/kWh x 1 kWh/0.003413 MBTU x __________ MBTU of electricity |
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= _______________ (fill in value and units) CO2 from electricity |
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b. 12 lbs CO2/therm x 1 therm/0.1 MBTU x __________ MBTU of natural gas |
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= _______________ (fill in value and units) CO2 from natural gas |
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c. 22.384 lbs CO2/gallon oil x 1 gallon/0.138095 MBTU x __________ MBTU of heating oil |
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= _______________ (fill in value and units) CO2from heating oil |
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d. 12.805 lbs CO2/gallon LPG x 1 gallon/0.0955 MBTU x __________ MBTU of LPG |
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= _______________ (fill in value and units) CO2from LPG |
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e. _______________ Combine the preceding results to get total CO2 from all sources of energy |
Energy Unit Conversions Worksheet: B
Complete this worksheet with the information found in Part II (efficient home). Show how the units cancel to yield the proper final
results. Note: The home you are modeling will probably not have all four types of energy shown below! Just skip the ones that are
not relevant.
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1. Convert raw energy to common units (millions of BTUs, MBTU): |
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a. _______________ kWh x 3413 BTU/kWh x 1 MBTU/1,000,000 BTU |
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= _______________ (fill in value and units) of electricity |
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b. _______________ Therms x 100,000 BTU/therm x 1 MBTU/1,000,000 BTU |
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= _______________ (fill in value and units) of natural gas |
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c. _______________ Gallons Oil x 138,095 BTU/gallon x 1 MBTU/1,000,000 BTU |
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= _______________ (fill in value and units) of heating oil |
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d. _______________ Gallons LPG x 95,500 BTUs/gallon x 1 MBTU/1,000,000 BTU |
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= _______________ (fill in value and units) of heating oil |
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e. _______________ combine the preceding results to get total energy from all sources |
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2. Convert MBTU of energy to greenhouse-gas emissions (pounds of carbon dioxide, CO2) |
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a. 1.2 lbs CO2/kWh x 1 kWh/0.003413 MBTU x __________ MBTU of electricity |
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= _______________ (fill in value and units) CO2 from electricity |
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b. 12 lbs CO2/therm x 1 therm/0.1 MBTU x __________ MBTU of natural gas |
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= _______________ (fill in value and units) CO2 from natural gas |
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c. 22.384 lbs CO2/gallon oil x 1 gallon/0.138095 MBTU x __________ MBTU of heating oil |
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= _______________ (fill in value and units) CO2from heating oil |
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d. 12.805 lbs CO2/gallon LPG x 1 gallon/0.0955 MBTU x __________ MBTU of LPG |
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= _______________ (fill in value and units) CO2from LPG |
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e. _______________ Combine the preceding results to get total CO2 from all sources of energy |
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