June 1997 Issue #16

Office Buildings Inside Factories

When you think of a factory's energy use, you probably imagine the energy consumed by pumps, motors, furnaces, stamping machines, and lathes. This may be true for traditional industries, but this stereotype doesn't apply to the high-technology sector. Building Energy Measurement and Performance Analysis staff Hashem Akbari and Osman Sezgen examined two buildings in the rapidly-growing high-tech industry to determine where the energy went. Microwave components were manufactured in one building and printed circuit boards in the other. The pattern of energy use in those buildings looked more like an office building rather than a factory, even though they had both process and fabrication facilities.

Building services--that is, lighting, heating and cooling, and ventilation--consumed 20 and 80% of the energy in these two buildings. A significant fraction of the floor area in both were devoted to conventional offices...right down to the water cooler at the end of the hall. Some of the design problems were familiar, but with a high-tech twist. For example, the room containing the lamination hot presses needed to receive the most cooling, so they put the thermostat in that room. Unfortunately, they ducted the cold air supply also to serve the shipping room, so there were always some shivering shipping room staff.

Energy use of the two buildings in kWh/m2. Equipment energy use is higher than office buildings, but the lighting and HVAC is typical.

Unlike an office building, the services were deliberately oversized in anticipation of future growth. Until that growth actually occurred, though, the equipment operated far down on the part-load curve. This resulted in low efficiencies.

A typical "high-tech factory" in Silicon Valley.

Getting more information about the factories of the future will be difficult because the firms owning these buildings are reluctant to allow anybody--even energy researchers--to visit the facilities. Sezgen contacted over fifty companies before finding two that were willing to let their buildings be studied. Even then, Akbari's and Sezgen's escort was scolded for allowing them inside a certain process facility.

-Alan Meier

Read the original cover letter mailed with this article on June 17, 1997.
For more information, please contact Alan Meier.

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