The office building of field test is located in Hamamatsu, the central part of Japan, where both space heating and cooling are necessary. Figure 2 shows the exterior view of the field test building and the interior view of the field test space provided with the building integrated solar thermal

system built in 2007. This office building is almost faced to South (Azimuth : 10 degrees to East). The roof with the integrated collector is tilted at 17 degrees. Two parts of the solar collection area is on the roof. Each solar collection area has the solar collector covered glasses of 60m2 and the

solar collector without glasses of 30m2. Two set of the solar desiccant cooling system are respectively installed in the attic space below the roof of the solar collection area. The office building is two stored with the total floor area of 1,560m2. The field test space is the office space and the civic hall of the ground floor with the floor area of 400m2 as shown in Figure 2. In addition, electric heat pump air conditioning units (EHP) are used for space cooling in summer and space heating in winter. The EHP is designed to be used only for processing the room heat load, because the solar thermal system processes the fresh air heat load. In summer, the high COP of the EHP is expected, because the latent cooling load is processed by the solar desiccant cooling system and the EHP has to process the sensible cooling load only. The monitoring period is a year from April,

2007 to March, 2008.