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Proceedings of BSO Conference 2020: Fifth Conference of IBPSA-England

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Optimal chiller loading of dual temperature chilled water plants for energy saving

Lizhi Jia, Junjie Liu, Shen Wei

Abstract: The chiller plant is one of the major sectors of building energy consumption. The Optimal Chiller Loading (OCL) in single-temperature chiller plants has been a hot topic to reduce the energy consumption of buildings, which has shown significant energy-saving potentials. A dual temperature chilled water plant commonly applied in systems that required low humidity, such as Make-up Air Units (MAUs) in Temperature and Humidity Independent Control (THIC) air conditioning system. A dual temperature chilled water plant has shown better energy efficiency than the single-temperature chiller plant for both cooling and dehumidification. In this paper, an optimal chiller loading strategy for dual temperature chilled water plants has been proposed, and the mathematical description of this optimization problem was defined first, including decision variables, objective function, and constraints. A meta-heuristic algorithm inspired by the dynamic mass balance principle, Equilibrium Optimizer (EO), was applied to solve the optimal control problem. Then, the performance of the proposed optimal control strategy was analyzed and compared with the conventional equal load control strategy on a dual temperature chilled water plant in a semiconductor fab. The results show that chillers with higher energy efficiency were assigned with a higher partload ratio rather than an equal value to achieve lower energy consumption of the entire chiller plant. Using the optimal control strategy could reduce the chiller plant’s power consumption ranging from 79.8 kW to 310.5 kW and achieve 3.3% to 13.1% energy savings than the average loading control strategy under different cooling load conditions.
Pages: 25 - 31
Paper:
bso2020_Jia