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Fully air-conditioned atria have become increasingly popular in architecture design due to their appealing aesthetic and iconic features to general public. In certain regions of China, climate diversities in winter (freezing-cold) and summer (warm-humid) are huge. Energy consumptions due to air-conditioning of atria in these regions are enormously high. Thus, their corresponding energy managements without compromising the indoor thermal comfort are extremely challenging. The geometric configuration of the atrium has preliminary and significant impacts on the indoor environment and further influences the energy consumption. The impacts of atria’s geometric configuration on indoor thermal condition and energy consumption under highly diversified climate conditions in China are studied in this paper. A fully air-conditioned enclosed atrium with square plane and cross-section is considered in this research. Atria with different section aspect ratio (SAR) and skylight sizes are investigated with a combination of (1) field measurements and computational fluid dynamics (CFD) simulations for temperature distribution and (2) energy simulations for the corresponding energy performance. Case studies for the temperature distribution profile for atria with different SAR and the quantitative correlations between atria’s SAR and its energy performance are presented. Optimum skylight size based on the objective function to minimize the annual energy consumption will also be reported. [ABSTRACT FROM AUTHOR]

Highlights: [•] Full-scale experimental data of atrium fire tests. [•] Assessment of stair stepping on the smoke layer and temperature field. [•] Validation of CFD numerical model FDS. [•] Numerical study for different area-to-height-squared ratio atria. [•] Good agreement between experiments and numerical simulations, especially far away from the fire source and the centerline. [ABSTRACT FROM AUTHOR]

Abstract: In this study, the thermal performance of various shapes and geometries of atriums in buildings is examined under various conditions. The goal of the study is to assess the impact of the atrium shape on the building total energy consumption and to identify the most energy-efficient atrium design. The study focuses on four different central atriums types with square and rectangular geometries which have same areas, use, schedule, controls, occupancy, and construction. The atriums exhibit different aspect ratios (length to width). Four cities in United States are selected to represent primary climatic regions of hot-dry, hot-humid, cold, and temperate. Besides, the atrium height, the atrium glazing type, and the glazing ratio are varied throughout the simulation process. Buildings models are constructed using the DOE-2.1E building energy simulation program. The results of this study indicate that in general, the total energy consumption of the narrow, elongated atrium or the rectangular atrium with high ratio of length to width is significantly greater than the square shaped atrium. [Copyright &y& Elsevier]

Abstract: Hybrid ventilation is the building ventilation system that integrates natural and mechanical ventilation components to create a high efficiency and healthy ventilation system for a building. Here, hybrid ventilation is used to control fire-induced smoke in a huge transit terminal subway station. Four different grid systems are compared, and the sensitivities of these gird systems are analyzed. The effect of hybrid ventilation on carbon monoxide (CO) concentration reduction and its suppression effect on horizontal dispersion of smoke are also analyzed. Heat release rate, smoke temperature in the vertical direction, smoke layer height and CO concentration are validated with previous experimental data, and good agreement is achieved. Preliminary results show that the average CO concentration in the hall decreases significantly with increasing roof window size and air change rate (ACH). However, little CO concentration difference in the atrium can be observed. Comparing with the conventional mechanical ventilation, hybrid ventilation can inhibit the dispersion of smoke more effectively. The CO concentration in the subway station in the horizontal direction is significantly lower than that with conventional mechanical ventilation. It suggests hybrid ventilation by setting roof window in the ceiling of the atrium with size of 3m×3m or larger can be an effective method to exhaust fire-induced smoke. [Copyright &y& Elsevier]

Abstract: Similarities of a reduced-scale building model using air as the working fluid for buoyancy-driven natural ventilation have been analyzed and experiments were carried out using the scaled model for a common natural ventilation building, which has open office floor plans connected to a central atrium. Both open and closed cases have been investigated for the stack vents, located at the top of the atrium. Inputs for the scaled building model were taken from results measured in the prototype building by the authors. The parameters of the scaled building model''s experiments thus were used as inputs into a computational fluid dynamics (CFD) simulation model to compare predicted and measured airflow patterns, temperatures and velocity distributions in the scaled building model. [Copyright &y& Elsevier]

Abstract: In recent years, highly glazed atria are popular because of their architectural aesthetics and advantage of introducing daylight into inside. However, cooling load estimation of such atrium buildings is difficult due to complex thermal phenomena that occur in the atrium space. The study aims to find out a simplified method of estimating cooling loads through simulations for various types of atria in hot and humid regions. Atrium buildings are divided into different types. For every type of atrium buildings, both CFD and energy models are developed. A standard method versus the simplified one is proposed to simulate cooling load of atria in EnergyPlus based on different room air temperature patterns as a result from CFD simulation. It incorporates CFD results as input into non-dimensional height room air models in EnergyPlus, and the simulation results are defined as a baseline model in order to compare with the results from the simplified method for every category of atrium buildings. In order to further validate the simplified method an actual atrium office building is tested on site in a typical summer day and measured results are compared with simulation results using the simplified methods. Finally, appropriate methods of simulating different types of atrium buildings are proposed. [ABSTRACT FROM AUTHOR]

Abstract: In winter, natural ventilation can be achieved either through mixing ventilation or upward displacement ventilation (P.F. Linden, The fluid mechanics of natural ventilation, Annual Review of Fluid Mechanics 31 (1999) pp. 201–238). We show there is a significant energy saving possible by using mixing ventilation, in the case that the internal heat gains are significant, and illustrate these savings using an idealized model, which predicts that with internal heat gains of order 0.1kW per person, mixing ventilation uses of a fraction of order 0.2–0.4 of the heat load of displacement ventilation assuming a well-insulated building. We then describe a strategy for such mixing natural ventilation in an atrium style building in which the rooms surrounding the atrium are able to vent directly to the exterior and also through the atrium to the exterior. The results are motivated by the desire to reduce the energy burden in large public buildings such as hospitals, schools or office buildings centred on atria. We illustrate a strategy for the natural mixing ventilation in order that the rooms surrounding the atrium receive both pre-heated but also sufficiently fresh air, while the central atrium zone remains warm. We test the principles with some laboratory experiments in which a model air chamber is ventilated using both mixing and displacement ventilation, and compare the energy loads in each case. We conclude with a discussion of the potential applications of the approach within the context of open plan atria type office buildings. [Copyright &y& Elsevier]

Abstract: An extended Gebhart–Block model for large space buildings is proposed in this paper, which is used to predict the vertical temperature distribution of hybrid ventilation. Natural ventilation coupled with air-conditioning is described with a mathematical model. The indoor thermal environment formed by the air-conditioning and the natural ventilation can also be conducted for the potential analysis and optimal use of the natural ventilation. Experiments were carried out in an atrium building in Shanghai Research Institute of Building Sciences. This paper describes aforementioned model, and it is found that the calculation results implying this model agree well with the measurement data. [Copyright &y& Elsevier]

This paper presents the field-measured energy performance of two common types of daylight-linked lighting control systems, continuous dimming and automatic on/off installed in two existing large atrium spaces located in Canada. The daylighting performance was evaluated based on the daylight contribution to the indoor illuminance and the amount of electrical lighting displaced by daylighting via the daylight-linked lighting control systems. Measured daylighting contribution to the space indicates that significant lighting energy savings can be achieved in atrium spaces if the daylight-linked lighting control system is appropriately selected, installed and commissioned throughout its existence. Results extrapolated from measurements collected during summer and winter indicate that as installed, the continuous dimming lighting control system provides 46% annual savings in electrical lighting consumption, while the automatic on/off saves between 11and 17% in lighting energy. These savings account for 68% of the lighting energy consumed during main occupancy for the continuous dimming system, and 31.5% for the automatic on/off. Operation irregularities such as a reduced dimming linearity and an incorrect adjustment of the phases of the dimming control system, as well as the inadequate location of the photocell controlling the automatic on/off lighting system, the improper maintenance of the skylight during winter and the oversizing of the lighting system reduced the energy efficiency of the lighting control systems by 30–65%. [Copyright &y& Elsevier]