CH-06-07-4 - Case Study of Demand Shifting with Thermal Mass in Two Large Commercial Buildings PDF

The idea of precooling and demand limiting is to precool buildings at night or in the morning during off-peak hours, storing cooling in the building thermal mass and thereby reducing cooling loads during the peak periods. Savings are achieved by reducing on-peak energy and demand charges. The potential for utilizing building thermal mass for load shifting and peak demand reduction has been demonstrated in a number of simulation, laboratory, and field studies.

In a preliminary case study in a government office building in California in summer 2003, it was found that a simple demand-limiting strategy reduced the chiller power by 80%- 100% (1-2.3 W/ft², 11-25 W/m²) from 2 p.m. to 5 p.m. without causing any thermal comfort complaints. This paper describes a follow-up study in 2004 in which tests were performed in two office buildings over a wider range of conditions. A Web-based comfort survey instrument was developed and used in the field tests to assess thermal sensation, comfort, and perceived productivity ratings in these two buildings.

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