Space-Conditioning Energy Requirements in the U.S. Commercial Building Stock

J. Huang, E. Franconi

The energy bill for the heating and cooling of commercial buildings is $40 billion a year, consuming nearly one-tenth of all the energy used in the U.S. The aim of this two-year project is to understand the characteristics of this energy expenditure by quantifying the contributions of major building components (such as roofs, walls, and windows) and end uses (such as lighting or equipment) to these space-conditioning loads (see Figure). This information is useful for comparing the potentials of different energy conservation strategies, identifying demand-side management opportunities, and allowing DOE to prioritize their building research activities.

The DOE-2 building energy analysis computer program is used to simulate the energy use of a large collection of prototypical commercial buildings developed in previous research efforts. A special procedure was developed to disaggregate the computed loads by building component and end use. The relationship of the building load to the energy requirement of the space-conditioning system is expressed as System and Plant Factors, which vary greatly depending on the system type, building operations, and climate.

The computed loads and energy use data are combined with building stock information from DOE's Energy Information Agency (EIA) to derive the total energy consumption for each commercial building sector, and then apportion it by building component and end use. The total space-conditioning energy use estimated by this engineering approach agrees within 5% of that from EIA's Commercial Building Energy Consumption Survey (CBECS).

Figure. Aggregate component loads for all commercial buildings (petajoules).

References

Huang YJ, Franconi EM. Commercial Heating and Cooling Loads Component Analysis. Lawrence Berkeley National Laboratory Report No. LBL-37208, 1995.

Huang YJ. Energy Use Characteristics of Prototypical Commercial Buildings. Lawrence Berkeley National Laboratory Report No. LBL-36021, 1995.

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