Optimal sizing analysis of water chillers in large air conditioning system

A large-percentage of the total energy consumption of the world is utilized in buildings, in which fifty to seventy percent is consumed by air conditioning system. Energy saving of AC system is obviously of great importance. Traditional AC system design philosophy based on the designing load. However, at most time AC system operates under part-load condition, which leads to performance deteriorating. Therefore, the more energy will be consumed if the system can't operate efficiently as the load changing. It is important to size water chillers appropriately so that each of chillers operates at high efficiency at most time. This paper, using HVACSIM(+), compares energy consumption of two systems in whole AC operation season. These systems are equipped with water chillers of different capacity and number. The results show that good sizing has an evident effect on energy saving: So AC engineers should not only choose chillers of enough capacity to serve the demand of maximal load, but also optimize the sizing of chillers on the basis of dynamic load curve.