Estimates of Energy Consumption by Building Type and End Use at Department of Defense Facilities

H. Akbari, S.J. Konopacki

End-use Disaggregation Algorithm (EDA) to develop end-use load shapes and intensities for prototypical buildings at the U.S. Department of Defense (DoD) facilities. In EDA, DOE-2 building energy analysis program simulations are reconciled hourly against measured energy consumption to obtain end-use consumption data. The objectives of this project were to : 1) develop an energy database by building type and end use for DoD facilities; and 2) enhance the DoD energy office's ability to track energy use by end use. In the process, we also transferred our analytical methodologies for end-use energy analysis to the U.S. Army's Construction Engineering Research Laboratory.

We initially achieved the objectives at one DoD installation, Fort Hood, Texas. At Fort Hood, the building types include a wide spectrum of commercial and residential buildings: barracks, dining hall, gymnasium, small and large administration, vehicle maintenance, hangar, hospital, warehouse, single-family detached, two-plex and four-plex units, and miscellaneous. As many as 11 end uses were developed for each prototype, consisting of nine electric (space cooling, fans/pumps, cooking, miscellaneous/plugs, refrigeration, exterior lighting, interior lighting, process loads, and street lighting) and two gas (space heating and hot water heating). Since, we had only hourly electricity-use data for the entire facility characterized by major electricity-distribution feeders, we reconciled only the electric end uses.

The EDA was applied to ten feeders in Fort Hood, and the results from the analyses of these ten feeders were extrapolated to estimate energy use by end use for the entire installation. Utility billing data for electricity use were used to validate the total energy use as estimated by EDA to within 5%, which was attributed to transmission losses. The extrapolation of the EDA results to the entire Fort Hood installation is shown in the Figure, where electricity use and peak power demand are depicted by both building type and end use. Administration, residential, and the barracks prototypes are the largest consumers of electricity, totaling 250 GWh per year (74% of Fort Hood's annual consumption of 330 GWh). Cooling, ventilation, miscellaneous, and indoor lighting consume almost 84% of total electricity use. The largest contribution to peak power demand is the residential sector (35%, 24 MW out of 70 MW), followed by administration buildings (30%), and barracks (14%). For the entire Fort Hood installation, cooling is 54% of the peak demand (38 MW out of 70 MW), followed by interior lighting at 18%, and miscellaneous end uses at 12%.

With existing technologies, energy-efficiency programs can be designed to reduce energy and peak demand use by 20% with a payback time of less than three years. Such a program at Fort Hood can result in an annual savings of 66 GWh and 14 MW.

In the second phase of this project, we are extending the annual energy-use intensitites obtained at Fort Hood to 20 other DoD installations nation-wide, representing all major climatic regions. However, the data available for these other facilities are very limited. Monthly utility electrical use data will be used in place of hourly data, and surveys of building characteristics are not available. We plan to use the Fort Hood prototypes and modify them based on the available data for other installations. Data identifying HVAC system type are virtually non-existent; consequently, fewer building types will be examined.

Figure. Percentage of electricity use (330 GWh) and peak power demand (70 MW) by building type and end use at Fort Hood, Texas, for 1993.

References

Akbari H, Konopacki SJ. End-use Energy Characterization and Conservation Potentials at DoD Facilities: An Analysis of Electricity Use at Fort Hood, Texas. Lawrence Berkeley National Laboratory Report No. LBL-36974, 1995.

Akbari H. Validation of an algorithm to disaggregate whole-building hourly electrical load into end uses. Energy-The International Journal 1995;20(12):1291-1301.

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