Computational analysis of wind tower-equipped sunken greenhouse for optimum microclimate control in hot arid regions

Abstract

This research focuses on designing, computationally modeling, and assessing a novel sunken greenhouse equipped with wind towers to create an optimum microclimate capable of enhancing crop productivity and quality while minimizing energy consumption in hot arid climates that present challenges like extreme ambient temperatures and intense solar irradiation. Three innovative, energy-efficient, and cost-effective techniques were integrated into the proposed greenhouse design: (1) Wind tower-driven natural ventilation, (2) fully sunken greenhouse structure, and (3) direct evaporative cooling. The airflow dynamics, solar heat transfer, and the interaction of moist air within the greenhouse environment were investigated to analyze the system’s performance and optimize its design. The results showed efficient ventilation rates and great improvement in the greenhouse’s internal microclimate in terms of temperature and relative humidity. The average airflow velocity inside the greenhouse, measured at 1 m height, ranged from 0.11 to 0.69 m/s for nominal wind speeds of 1–6 m/s, while air changes per minute range is 0.28–1.7. Even under extreme ambient conditions (30–45 °C, 15–50 % humidity), the proposed greenhouse mostly maintained temperatures below 35 °C, reducing interior air temperatures by up to 11.7 °C from the ambient and increasing humidity by up to 57.1 %. The economic feasibility comparison of the proposed greenhouse to a conventional active-cooled greenhouse showed a remarkable 74.5 % reduction in the life cycle cost of the microclimate control technique.

Keywords

• Computational fluid dynamics (CFD)
• Food security
• Greenhouse
• Hybrid cooling
• Natural ventilation
• Sustainability