Energy optimization in chiller plants: A novel formulation and solution using a hybrid optimization technique

Abstract

The central chilled water plant is one of the major power-consuming units of a building. Even small reductions in power consumption could achieve significant energy conservation. Hence, optimization of a chiller plant is necessary for energy savings without compromising the comfort level of the end user. The present work deals with identifying the system parameters and developing a novel formulation for a chiller plant and its optimization using a hybrid optimization technique. The optimization model formulation is based on finding an optimal mix of equipment and operating parameters in the chiller plant for minimum electrical power consumption. It takes into account the performance characteristics of the chillers, cooling towers and pumps, and optimizes the energy consumed based on the required loads and the ambient atmospheric conditions. Sequential quadratic programming combined with the modified branch and bound method was used to develop the hybrid optimization algorithm. A case study is presented for a typical chiller plant. The results indicate that the present optimization method could be a potential method of making energy savings.

Keywords:

• chiller plants
• energy conservation
• sequential quadratic programming
• branch and bound method
• mixed discrete optimization

Acknowledgements

The authors would like to thank Mr. Igor Gonzalez, ESI Consulting Engineers, for his invaluable support in the present work.