CFD-Optimized Radiant Cooling with Dedicated Outdoor Air System (DOAS) for High Ceilinged Spaces in Hot and Dry Climates

The increasing demand for sustainable and energy efficient buildings, and fast-track delivery of projects with limited design time, has driven the need for advanced design tools to accurately assess and optimize ever more complex and diversified design strategies to find ways to reduce loads, boost efficiency, and utilize renewable resources. Computational Fluid Dynamics (CFD) proved to be a solid and flexible platform for design development and validation to meet such challenges within tight schedules, and deliver state-of-the art designs for high performance buildings.This paper will present the use of computational fluid dynamics (CFD) simulations at Dar Al-Handasah to develop an innovative air-conditioning system for high-ceilinged spaces in hot and dry climates based on radiant cooling coupled with a dedicated outdoor air system (DOAS). Specifically, the performance effectiveness of the proposed cooling strategy in establishing a comfortable thermal environment is compared against a conventional overhead supply ceiling diffusers system by conducting a detailed investigation of airflow delivery and temperature distribution in a typical transient high-ceilinged assembly hall during full load and part load conditions. Moreover, to analyze accurately the performance of the compared VAC designs, several parameters have been considered such as the supply air flow rate and temperature, the air distribution layout, radiant floor temperature and heat loads.The findings indicate that the proposed cooling strategy based on a combination of radiant cooling with DOAS helped achieve a thermally uniform environment with markedly improved thermal comfort conditions and reduced energy use as compared to the conventional design and the study concludes with a set of recommendations to optimize the air conditioning system energy use and thermal comfort levels in such spaces.