Though more costly to install and more complicated to operate, a chiller plant offers a number of benefits over simple packaged cooling units, including greater energy efficiency, better controllability, and longer life.

Chilled water-based cooling systems are frequently used to aircondition large office buildings or campuses that encompass multiple buildings. They represent a large investment from the perspective of first cost, physical space they require within the building, as well as energy and maintenance cost. Yet despite these fiscal and spatial impacts, many chiller plants do not reach their potential from the standpoint of energy efficiency. In the past, California's Title 24 Energy Efficiency Standards for Non- Residential Buildings did not have particularly aggressive efficiency standards for chillers, but this has changed with the 2001 revision of the code. In some cases, the 2001 Standards have increased efficiency requirements by as much as 25 percent. Chiller plants that easily complied with older Title 24 Standards might not be efficient enough to meet the 2001 Standards.

The strategies discussed in this design brief can provide the basis for designing chilled water cooling systems that can beat the more aggressive 2001 Title 24 Energy Efficiency Standards by 30 percent or more.

The first edition of this design brief was prepared for Energy Design Resources in 2003. Between January and April of 2010, an engineering review of this document was conducted to update passages affected by recent changes in the California Building Energy Efficiency Standards (Title 24 2008). The original content creator was not actively involved in this engineering review, and therefore is not responsible for the updates to the affected passages.