In recent times, server power utilization in data centers has increased considerably. Liquid immersion cooling systems in combination with conventional air-cooling systems for low-load hard disk drive (HDD) storages are used at data centers having high load servers. In our previous study performed last fiscal year, we modified the configuration of such a cooling system, based on our experimental results and annual energy consumption simulation. In this study, which was performed during the final fiscal year of our project, we measured the power consumption and power usage effectiveness (PUE) of our proposed cooling system and demonstrated its annual average PUE to be approximately 1.02, based on seasonal experiments. In addition, we have also obtained an annual average PUE distribution through a simple estimation based on the data obtained using the wet-bulb temperature of air in Japan.