Experimental and numerical optimization on chilled water configuration for improving temperature performance and economic viability of a centralized chiller plant

Abstract

This research aimed to simulate and optimize chilled water circuit system of a central air conditioning plant applied for a five-star hotel in Bali Island, Indonesia. This optimization was performed because temperature of chilled water distributed to the loading system could not satisfy room temperature requirement. Detailed measurements have been taken on the AC system included refrigeration system of the chillers, chilled water and cooling water distribution, cooling load, heat rejection and pumping systems. Thermodynamic analyses on the system energy performance were carried out. Numerical simulations were also established to evaluate chilled water flow rate in the primary and secondary circuits. The measurement and simulation results showed there was unbalanced chilled water flow rate between primary and secondary circuits and the chilled water flow rate did not comply with rule of flow ‘primary flow must always be equal to or greater than secondary flow’ resulted in the cooling load coils lost their cooling capability. Optimization on the chilled water flow rate between primary and secondary circuits by implementing variable speed pumping system incorporated balancing valve was estimated to be potentially improve temperature performance and economic viability of the chiller plant operation.