Multi-Building Central Plants

Opportunities for energy efficiency a re often investigated for the buildings of a campus, without afocus on the central plants serving the multi-buildine C£llI1pUS, Quite ojten, a majority of the energy efficiencr opportunities ore present ill the central plants, ln such pia 11ts, ret rofi II ing the central plants with tuore efficient equipment or changing operating strategies can have a significant reduction in the total campus energy usage. However, linlike the efforts to develop consensus standards, such as the U.S, Department of Energy's International r Performance Monitoring and Verification Protocol (DOE 2001), the Federal Energy Management Program '.I' Measurement and Verification Guidelines (FEMP 2000), or the Anterican Society of Heating, Refrigerating and Air-Conditioning Engineers' Guideline 14P (ASHRAE 2001), very little work has been performed to develop a standard method for boselining the energy use ofa multi-building central plant, The lack of such a consensus method makes it difficult to verify the savings from energy conservation efforts in central plants, such as those included in energy savings performance contracts. This paper discusses the results ofefforts to develop and test a procedure for baselining the energy use ofa large multibuilding central plant. The methodology consists ofa series of interconnected inverse or statistical models that can develop' a baseline that is normalized for differences in year-to-year, weather variations. equipmentperformance. equipment selection, and campus loads. This paper describes the methodology and presents the results of the application ofthe methodology to a large university campus in central Texas. Jeff S. Haberl, Ph.D., P.E. Member ASHRAE David E. Claridge, Ph.D., P.E. Member ASHRAE