Japan Sustainable Building Database

A/C system using large temperature difference with cascade control

Heat source/air conditioning system overview

An ice thermal storage system combined with a super high-efficiency chiller is used as the heat source. Secondary A/C links FCU with AHU, using return air from FCU in AHU with cascade control. The system performs processes such as water conveyance using temperature difference of 13°C in summertime and water heat exchange in AHU after temperature of cold water is first raised in FCU in wintertime. The processes allows the temperature of outdoor air diffused inside the building to be raised to 15-16°C and enables heat recovery from cold water by lowering its temperature by 3-4°C using even colder outdoor air, thus achieving a reduction in A/C energy consumption. It also significantly contributed to electric-load leveling, as approximately half of power consumption has shifted to night-time (annual night-time power consumption of heat source: 53%).

Light wells

A light well in the mall's ceiling

Daylight is utilized to provide natural light in the mall through openings in vaulted ceiling