A hybrid monitoring-modeling procedure for analyzing the performance of large central chilling plants

This paper presents a methodology to effectively model the performance of central chilled water plants in campus or multi-building complexes where detailed modeling of every building served by the plant is out of the question, usually due to budgetary and/or time constraints. The work presented has evolved through years of practical experience in the analysis of central chiller plant performance for the purpose of justifying the economic merit of loadshifting and energy-saving strategies. The proposed method has been used strictly for retrofit applications, but is also applicable to new plants if enough parameters are known. Throughout the years the author has found that this methodology requires significantly less effort than using the more complex building hourly simulation programs, and often allows greater flexibility in addressing conditions which are not within the scope of commercial modeling programs. The following sections justify the need for this type of approach and provide a detailed description of the procedure using data and results from a real project.