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A new comprehensive evaluating method for assessing the sustainability credentials of the central air-conditioning system

A new comprehensive evaluation method for assessing the sustainability credential of central air-conditioning systems is proposed in this paper. The method is based on the relative coefficient index (K) of costs and benefits of the air-conditioning system. The paper introduces the concept and defined the parameters of costs (energy consumption costs, economic running costs and environmental impact) and benefits (indoor air quality and thermal comfort) and the mathematical principles for the determination and evaluation of these parameters. The parameters are then ranked with an index value for each component that make up the air-conditioning system, and the total index value would be used for the overall evaluation of the costs and benefits to determine the overall index, K. The feasibility of the method is illustrated by three case studies included in this paper. The evaluation index can identify shortcomings of components in the air-conditioning system and to identify the relative environmental impacts and costs as well as the performance in using the system. The evaluation index would thus allow designers and building managers to target performance improvements and guide designers to optimize functions in terms of costs and benefits to minimize environmental impacts. The index method would provide a rating classification of air-conditioning systems for standard specification and selection in terms of cost effectiveness for appropriate building service required.