Abstract: Ventilation is a fundamental requirement for
occupant health and indoor air quality in buildings. Natural
ventilation can be used as a design strategy in free-running
• Renew indoor air with fresh outside air and lower room
temperatures at times when the outdoor air is cooler.
• Promote air flow to cool down the building structure
• Promote occupant physiological cooling processes
This paper focuses on ways in which ventilation can
provide the mechanism for heat dissipation and cooling of the
building structure..It also discusses use of ventilation as a
means of increasing air movement to improve comfort when
indoor air temperatures are too high. The main influencing
factors and design considerations and quantitative guidelines
to help meet the design objectives are also discussed.
Abstract: This paper presents the climatic range calculations for
comfort evaporative cooling for Tehran. In this study the minimum
climatic conditions required to achieve an appropriate comfort zone
will be presented.
Physiologically uncomfortable conditions in arid climates are
mainly caused by the extreme heat and dryness. Direct evaporative
cooling adds moisture to the air stream until the air stream is close to
saturation. The dry bulb temperature is reduced, while the wet bulb
temperature stays the same. Evaporative cooling is economical,
effective, environmentally friendly, and healthy.
Comfort cooling by direct evaporative cooling (passive or fan
forced) in the 35. 41 N (such as Tehran) latitude requires design
wet-bulb temperature not over 25.4 C. Evaporative cooling outside
this limit cannot achieve the required 26.7 ET, and is recommended
for relief cooling only.