**Nomenclature**

The total cost implications are presented in **Table 10**. The cumulative costs and

**Figure 16** depicts the relationship between the cost of solar chimney and fans against number of years. It can be observed that the cumulative cost of running the mechanical ventilation system (fans) kept increasing continuously by over 30% each year and that of passive ventilation was lesser with about 12.5%. This indeed tells that the use of the solar chimney for ventilation is less costly, and invariably,

**Figure 17** shows a relative increase in cost over number of years with the use of fans. It can be deduced that there was a 66.69% increase in cost due to the use of fans compared to the use of solar chimney in the lecture room for over 10 years. Therefore, with this percentage increase it can be understood that there is more energy and cost saving potential for the use of passive ventilated systems than

Passive ventilation systems are a natural ventilation technique that has the potential of saving energy as well as maintaining good air quality in a building as compared to mechanical ventilated systems. This research was carried out with the aim of improving the ventilation performance (thermal comfort and indoor air quality) of a lecture hall. In this project, a detailed and systematic assessment of a lecture hall using CFD simulations was performed for determining the air flow caused by wind velocity stratification (0.05–2.0 m/s), solar radiation (200–

openings. The air change per hour was deduced using different boundary conditions in the lecture room. The research revealed the airflow and temperature pattern within the room. It was obtained that a solar chimney of size between 1 and

were achieved and in turn a contribution to knowledge.

buildings like lecture rooms, conference halls, etc.

in the public, commercial, or not-for-profit sectors.

The authors declare no conflict of interest.

) and pressure outlet of 1 atm within a space with seven ventilation

, improved the natural ventilation in the room. Also, from an energy and cost analysis carried out, cost-saving potential of the passive system (solar chimney) was established and found to be both energy and cost-effective in comparison to mechanical systems for better indoor air quality and thermal comfort. There was a 66.69% increase after 10 years in the saving of energy and cost using Solar Chimney (SC) as compared to fans. It is therefore acceptable to state that objectives

The knowledge of temperature stratification and mass flow rate is essential so as to aid the thermal comfort of occupants in indoor environments, especially in public

The inputs and critique of members of the research team are acknowledged and appreciated. This research did not receive any specific grant from funding agencies

respective percentage increases are presented in **Table 11**.

*Zero-Energy Buildings - New Approaches and Technologies*

energy efficient.

**5. Conclusion**

1000 W/m<sup>2</sup>

**Acknowledgements**

**Conflict of interest**

**96**

100 m<sup>3</sup>

mechanical ventilated systems.

