Optimal design and operation of the hybrid absorption-compression chiller plants - Energy and economic analysis

A hybrid network integrating absorption and compression chillers is a suitable solution to respond to the variable cooling demand in a large-scale chiller plant, in regions with multiple energy sources. However, the design and control challenges of such networks remain uncharted, lacking a comprehensive approach. This study presents a general procedure for designing a hybrid chiller network for a building with an arbitrary annual cooling demand distribution. The procedure determines the optimal configuration considering the different capacity ratios of absorption to compression chillers, chiller numbers, and arrangements. Utilizing the Particle Swarm Optimization algorithm, the optimal chiller loading distribution is found for each configuration. Life cycle cost analysis aids in selecting the optimal configuration. Simulations conducted in TRNSYS, reveal that optimal energy and economic choices depend on the natural gas and electricity price ratio. The best energy performance occurs at a low capacity ratio, while the economic trend varies with capacity ratio for different price ratios. The potential reduction in life cycle cost associated with the configuration, when compared to the full absorption baseline and the full compression baseline, can reach up to 7,210,000 $ (72.6%) and 724,000 $ (24.5%), respectively. From an environmental perspective, compared to the full absorption baseline and the full compression baseline, hybrid chiller configurations reduce the CO₂ emissions for up to 899 tons (68.8%) and 52 tons (11.3%), respectively.