Fully mixed air model based cooling load estimation method for both stratum ventilation and displacement ventilation

The non-uniform indoor thermal environments of stratum ventilation and displacement ventilation help to reduce the energy consumption, but challenges the cooling load estimation for the energy performance evaluation of air conditioning systems during the design and operation. Co-simulations coupling the building energy simulation and indoor thermal environment simulation are getting popular for the cooling load estimation of the non-uniform thermal environment for the research studies, but they are time-consuming and technologically complicated for practical applications. This study proposes a method to enable the fully mixed air model to accurately estimate the cooling load for both stratum ventilation and displacement ventilation. The main idea of the method is to determine a height of the stratum-ventilated/displacement-ventilated room at which the air temperature can be used as the input of the fully mixed air model to accurately estimate the cooling load of stratum ventilation/displacement ventilation. Experimentally validated multi-node models are employed to demonstrate the effectiveness of the method proposed. Since the fully mixed air model is readily available in existing building energy simulation tools, familiar to building energy engineers and computationally efficient, this study contributes to providing a computationally efficient and technologically convenient method to accurately calculate the cooling load of stratum ventilation and displacement ventilation for building energy engineers.