Today, it is recommended to raise the cooling temperature setting as a method of saving energy in building air conditioning. However, many air conditioners depend exclusively on dry-bulb temperature control and during the rainy season, their dehumidifying capacity for latent heat may be insufficient, resulting in discomfort. One of the causes of the latent heat load, which is a factor in this discomfort, is often the intake of outdoor air by ventilation. This time, we have commercialized a humidity control outdoor air processing direct expansion air handling system (Direct X Comfort), which has a cooling dehumidification function that controls the dew point temperature and a reheating function that utilizes waste heat, in addition to the functions of conventional outdoor air processing direct expansion air handling systems. By using waste heat from the heat pump as the heat source for reheating, this system has achieved a 60% reduction in power consumption compared to the conventional desiccant system that uses an electric heater as the heat source for regeneration.