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Monthly Indices: A Procedure for Energy Use Display Creating Monthly Indices for Comparing the Energy Consumption of Buildings
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This technical paper describes the construction of comparative monthly energy and weather indices for buildings and their usefulness in simple comparisons across sites. These graphs show monthly electric and natural gas average power levels (i.e., W/sf and Btu/hr-sf). The electricity power levels allow for the comparison of both electric demand and electricity consumption on the same graph (i.e., it is time independent). Power levels have been shown to be a useful way of displaying building energy use by MacDonald (1988) and by Haberl and Komor (1989). Other indices include Electric Load Factor (ELF), Occupancy Load Factor (OLF), and People Load Factor (PLF). ELFs are commonly used by utilities to evaluate a customers average electric load profile. OLFs and PLFs have been shown to be a useful way of determining the average monthly occupancy of a building (Landman 1996). Weather indices are also useful in determining energy use of building. Use of the energy and weather indices will help a building owner quickly decide if a building is energy efficient when compared to other buildings and if a detailed study should be performed to facilitate energy conservation measures.
energy and weather indices
Electric Load Factor
Occupancy Load Factor
People Load Factor
Landman, D. S.; Haberl, J. S. (1996). Monthly Indices: A Procedure for Energy Use Display Creating Monthly Indices for Comparing the Energy Consumption of Buildings. Energy Systems Laboratory (http://esl.tamu.edu), Texas A&M University; Department of Mechanical Engineering, Texas A&M University. Available electronically from