抄録
This research proposes operational method to improve system efficiency regarding water cooled packaged Air-conditioning (A/C). Water cooled package A/C works all year air cooling and is installed at telecommunication building and data center. As an A/C which performs annual A/C operation, the operation range of the low-temperature domain of condensation temperature was expanded, and the air cooled packaged A/C machine has so far realized technology which raises the efficiency in every year. This technology can be applied to a water-cooled package A/C, and improvement in efficiency of a refrigeration cycle can be aimed at by lowering circulating water temperature. On the other hand, the efficiency in the whole A/C system reeds to consider and estimate the power consumption of a cooling-water system. The simulation model incorporating the control technique which reduces the power of the cooling-water system by operation/stop control of a cooling tower was created, and the system efficiency through every year was computed from steady-state simulation of a system. Consequently, at the efficiency of an A/C system including a cooling-water system, lowering the minimum value of circulating water temperature did not necessarily restrict that it was good, but it became clear that there is the operation temperature range of the optimal cooling water according to the operating ratio of an A/C machine. And, it was expected by proposed control that it improved about 12% at the time of the partial load of 30% of A/C machine operating ratios
