Abstract
For the designing data of a hybrid air-conditioning system utilizing natural and mechanical ventilation, the characteristics of the indoor thermal environment are examined with CFD (Computational Fluid Dynamics) simulation under the various conditions of mechanical air-conditioning system, indoor heat generation rates and the width of office room. Also, cooling load of the mechanical air-conditioning system to maintain the task zone at the target temperature (26℃) is analyzed based on the results of these simulations. Floor supply ceiling return air-conditioning system is energy conservative as it cools the task zone effectively. Cooling load of mechanical air-conditioning system is increased as heat generation rates and the office width are increased. By the effective heat exhaust at the outflow window opening, however, its increasing rates is smaller than the conditions under the perfect mixing assumption cases. From the results of case studies, a simple cooling load model implying energy conservation effect of hybrid air-conditioning system was proposed. The point of this cooling load model is that the temperature stratification in a room is considered in building energy simulation (net work. simulation) for long term. With the model, energy simulation for the office building of 25 stories was conducted. The results show that energy conservation rate of 16% is achieved.
