6. Macroclimate analysis

Cairo's climate is a desert climate, which remains mostly dry and arid yearround. The hot weather in Cairo means that the humidity can rise at times, particularly during winter (December to February). At this time precipitation is more likely, and temperatures drop to 13–19°C. Cairo weather in the summertime (May to August) sees temperatures of 45–47°C. The Cairo International Airport weather Station was chosen to most represent the location of new Cairo. The hourly climatic

## Green Building Rating Systems as Sustainability Assessment Tools: Case Study Analysis DOI: http://dx.doi.org/10.5772/intechopen.87135

data file generated by the USDOE was used in this report. On analyzing the hourly climatic data using Weather Tool, Cairo climate is classified as an arid climate where precipitation rarely occurs. Cairo has a hot desert climate (Köppen climate classification: BWh). The climate is generally dry. The temperatures are hot or very hot in summer days and warm or mild in winter days, but warm in summer nights and cool in winter nights. The temperature varies greatly, especially in summer; it ranges from 7°C at night to 40°C during the day. While the winter temperature does not fluctuate as wildly, it can be as low as 0°C at night and as high as 18°C during the day. Cairo receives less than 25 mm of precipitation annually in most areas and almost never rains in summer. Air temperatures are being outside the comfort zone most of the year. Only during 4 months (March, April, September, and October), a good percentage of the total hours is found to be located in the comfort zone. The prevailing wind is coming from the north to northwest most of the year with average air temperature, while hot wind comes from the west-south direction during specific times of the year. Prevailing wind are coming from the north to northwest most of the year with average air temperature, while hot wind comes from the west-south direction during specific times of the year. Rainfall is rare in Cairo and does not exceed 25 mm/the whole year.

Passive solar heating, thermal mass effect, night purge ventilation, natural ventilation, direct evaporative cooling, and indirect evaporative cooling to enhance the environmental performance of the GREENEDGE in Cairo were tested using Weather Tool. The analysis revealed that while thermal mass and night purge ventilation can enhance the thermal performance during the whole year, almost only natural ventilation can enhance significantly the environmental performance of the building during the summer season. While indirect evaporative cooling can enhance the thermal performance slightly during the summer time, passive solar heating can also contribute to the thermal enhancement during winter time. Using Mahoney table, it revealed that it is essential to deal with such climate to use the following strategies:

