The solar desiccant cooling system is composed of two air handling units and the operation mode is switched. Therefore, the switching time point is important.

At first, when the collected hot air temperature is 40 degrees C, a air handling unit is started in regeneration operation. The other air handling unit is not operated yet. When the regeneration operation is finished, the operation mode of the air handling unit is changed to the dehumidification mode and the other air handling unit is started in regeneration operation. From the finish of the regeneration process at the one air handling unit, the solar desiccant cooling system is operated in regeneration process and in dehumidification cooling process at the same time while the operation mode is switched. When the relative humidity of the primary desiccant

module outlet air is 10%, it is judged that the regeneration is finished. In addition, the regeneration time limit is set for the cloudy days.

Fig. 2. Outdoor and indoor view of field test building.

Dehumidification cooling process
Regeneration process

MD

AHU A

Foundation pit

Fig. 3. Solar desiccant cooling operation in summer.

In winter, this solar desiccant cooling system is used for the solar space heating system. Therefore, this solar thermal system is the solar space heating and ventilation system in winter and the solar desiccant cooling and ventilation system in summer. The solar space heating system is operated for the collected hot air temperature of 30 degrees C in winter.

2. Field Test