Figure 3. Psychometric Chart for Central Jakarta

3.2 Climate

The tropical monsoon climate of Jakarta sees about 9 months of wet-humid conditions with daytime temperatures exceeding 30°C (>90% of the year) and reaching up to 31°C. The city receives ~1.7m of rainfall (annual average). Dry-humid conditions are observed for the remaining 2 and a half months. The city experiences high humidity (>70%) and frequent precipitation together with daytime temperatures dropping below 26°C and remaining close to comfortable values (below 30°C) on an average. Climatic conditions, therefore, remain on the warmer side for most part of the year with a brief period (about 3 months) of mild winters, with warm days and cool nights. During the summer-fall months, West and South faces receive maximum daylight whereas, East would benefit from sun shading. In the winter-spring month, East receives less daylight. Throughout the year, total surface radiation is high, with global horizontals surpassing 800 Wh/sqm for majority of the year. Jakarta's coastline location experiences high wind velocities from all directions, with wind speeds surpassing 8 m/s. The strongest wind speed was measured in January (>13 m/s) As per ASHRAE Standard 55-2004, the project site perceives zero comfortable zones in relation to temperature and relative humidity established via a psychrometric chart. The chart suggests that up to 40% comfortable hours can be achieved through sun shading and dehumidification only. However, this depends on the type of system used to achieve the desired result. Remaining 60% comfortable hours could be achieved using mechanical ventilation and lighting strategies (See Figure 3).

(a) Passive strategies (b) Active systems

Figure 3. Psychometric Chart for Central Jakarta. (a) Passive strategies (b) Active systems