Central and split systems are the two most common air conditioning (AC) systems used in residential applications. Central system employs one large unit to produce and distribute conditioned air through a system of ductwork. On the other hand, the split system, employs several small ACs. Each AC consisted of outdoor and indoor units to produce conditioned air directly to the designed area. Each system has distinct strengths and weaknesses. Depending on the structure of cooling area and operating schedule, the performance of each system will be different. The aim of this paper is to examine the impact of various parameters such as operating schedule and building characteristics to the performance of central and split AC systems over the 25 years of their operation. The life cycle analysis (LCA) considered essential factors which have significant impact on the energy consumption and both initial and operating costs of the two systems. All required sections of life cycle analysis are included according to the relevant Australian Standards. The results indicated that under standard operating conditions, central system is more economical and energy efficient than split system. However, when the flexibility in operation of split system is considered, there was a significant reduction in its operating cost, which was below that of central system. Overall, total life cycle cost of split system was slightly lower than central system. Also, considering the usage flexibility and the comfort of users, it appears that the split system is more suitable than the central AC system for residential buildings.
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