Abstract Multiple-chillers systems represent viable solutions for medium/large-scale air conditioning applications characterized by variable cooling demand. The energy efficiency of such systems is influenced by the number of chillers, the combination of cooling capacities, and the load-sharing among the units. Large efforts have been devoted to developing efficient operation strategies for these systems, but rules of thumb are usually adopted for selecting cooling capacities thus leaving room for energy and economic savings. In this paper, exergoeconomic analysis is proposed as a promising method to identify near-optimal design and operation strategies, due to the capability of exergoeconomic indicators to account simultaneously for capital and operating costs. The potential of the method is illustrated for a hydronic system supplying an air-handling unit installed in an office building. Design alternatives are compared, with chillers of equal or different capacities operated in a parallel or series configuration, and the cost-effectiveness of different load sharing strategies is also investigated. A thermoeconomic model for multiple-chillers systems is formulated, considering the actual performance of chillers under full- and part-load conditions derived by a plant simulator. Results show that the exergoeconomic cost of chilled water reduced by about 7% and 30% when passing from evenly to unevenly sized systems in both series and parallel configurations. It is also found that the symmetric load sharing strategy leads to a 14–18% reduction in the cost of chiller water compared to the sequential one. The study confirms that this method may represent systematic and thermodynamically-sound support for engineers in this field.

中文翻译：

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Exergoeconomic 分析作为空调应用中多个冷却器系统设计和运行决策的支持

摘要 多冷却器系统代表了以可变冷却需求为特征的中/大型空调应用的可行解决方案。此类系统的能源效率受冷却器数量、冷却能力组合以及机组之间的负载分配的影响。已投入大量精力为这些系统制定有效的运行策略，但通常采用经验法则来选择冷却能力，从而为能源和经济节约留出空间。在本文中，由于exergoeconomic 指标能够同时考虑资本和运营成本，因此exergoeconomic 分析被认为是一种确定接近最优的设计和运营策略的有前途的方法。该方法的潜力说明了为安装在办公楼中的空气处理单元供电的水力系统。对设计备选方案进行了比较，将相同或不同容量的冷水机组以并联或串联配置运行，并且还研究了不同负载分配策略的成本效益。考虑到由工厂模拟器得出的全负荷和部分负荷条件下的冷水机的实际性能，制定了多冷水机系统的热经济模型。结果表明，在串联和并联配置中，从大小均匀的系统变为不均匀大小的系统时，冷冻水的运行经济成本降低了约 7% 和 30%。还发现，与顺序策略相比，对称负载共享策略可将冷却水成本降低 14-18%。