**3. Comfort ventilation**

A thermal insulation, 0.1 m thick, is installed inside the floor layer to examine the performance of the integrated SCPC system for indoor thermal comfort while excluding heat effect from the ground. The SCPC system consists of two components: the solar chimney and the short wind tower. The solar chimney was fixed on the roof of the room facing south. The SCPC system is made from widely available and conventional materials in the Egyptian market. The solar chimney is made from black aluminum with emissivity 0.95 and glass with transmissivity 0.84 and thicknesses of 0.002 m and 0.1 m, respectively, as shown in **Figure 4**. Performance of the solar chimney was examined in the first phase. The maximum airflow rate

**Figure 5.** The description of evaporative technique in the wind tower made from expanded paper with water droplet

[17, 18].

in the chimney was 0.69 kg/s during a high solar radiation of 890 W/m<sup>2</sup>

**Figure 4.** Cross section of the solar chimney cross section.

88 Energy Systems and Environment

from upper side.

Comfort ventilation is the important factor that deals directly with the human body and depends on the strategy used. It is based on the theory that high airspeed around the human body accelerates the skin's evaporation rate and, accordingly, improves the heat dissipation from the human body. This in turn shifts up the comfort upper level by providing such direct physiological cooling effect and decreases human discomfort due to skin wetness and the high humidity level [20]. In comfort ventilation strategy, two different impacts of the air velocity of the human body were determined: first, the heat exchange of the body that happens with convection; second, the evaporative capacity of the air. According to ASHRAE Standard 55 for naturally ventilated buildings, the acceptable thermal environment of indoor operative temperature ranges between 22°C and 28°C, and the comfort indoor air velocity of 1.6 m/s can be beneficial for improving comfort at higher temperatures [19]. So, new residence must have the acceptable thermal environment for all occupants. According to ASHRAE Standard 62–2001, ventilation rates depend upon the floor area, whereas the minimum ACH was 0.35, but no less than 15 CFM/person [21]. Also, passive natural ventilation standards require a minimum of three air changes for residential buildings. Finally, the comfort ventilation can easily be enhanced by appropriate building design and the system used.
