Applied Mechanics and Materials Vols. 368-370

Abstract: This study focuses on the performance of air conditioning design at the Dazhi Cultural Center and uses a computational fluid dynamics (CFD) simulation to discuss the differences in wind velocity and ambient indoor temperature between all-zone air conditioning design and stratified air conditioning design. The results have strong implications for air conditioning design and can improve the indoor air quality of assembly halls.

Abstract: This study focuses on the efficiency of passive solar chimney in natural ventilation performance of the conference hall at the Magic School of Green Technology (MSGT) in Tainan, Taiwan. The air exchange rate in the conference hall was between 5.73 ACH and 9.11 ACH, which exceeded the minimum air ventilation rate required in Taiwan. This shows that a passive solar chimney can effectively applied to the conference hall to meet indoor ventilation and air exchange requirements without using air conditioning.

Abstract: In cold rural areas of Eastern China, heating energy consumption was increased year by year, affected by some factors such as building materials, different courtyard layouts and residential constructions. Based on field measurements and multiple perspectives analysis of typical houses, the heat of cold air infiltration in one house could be reduced by 18.3 %, while the courtyard design was adapted to local climatic conditions. Heating energy consumption could be reduced by 15% for reasonable energy utilization, and which could be reduced by 50% for rational design of building layout and correct selection of materials for building envelope.

Abstract: The present study developed a computational fluid dynamics (CFD)-based performance simulator for assessing natural ventilation effectiveness to the central patio and corridors of the new administrative building of the Guanyin Township, Taiwan. The data can share with other potential users for achieving better understanding of the indoor microclimate and the interaction of buildings with urban wind environment for improvement of their design and functioning aspects during the decision-making procedure.

Abstract: This study applied the thermoelectric chip design and the establishment of the personalized air-conditioning system in the design of the single duct and double duct structures. According to the actual measurement results when the ambient temperature was 29°C, the air outlet temperature of the two structures was 22°C, 24°C respectively; the power consumption was 133W, 134W respectively. FLUENT was used to simulate the spatial flow field and temperature field for comparison to learn about the spatial temperature distribution status of the air-conditioning system.

Abstract: For the purpose of avoiding the deficiency of the traditional construction ventilation, the ventilation of the underground main powerhouse is simulated by the computational fluid dynamics (CFD) to optimize ventilation parameters. A 3D unsteady RNG k-ε model is performed for construction ventilation in the underground main powerhouse. The air-flow field and CO diffusion in the main powerhouse are simulated and analyzed. The two construction ventilation schemes are modelled for the main powerhouse. The optimized ventilation scheme is obtained by comparing the air volume and pressure distributions of the different ventilation schemes.

Abstract: Green building has become the trend of urban development in the twenty-first century as the threat of global warming is ever more challenging. The traditional Tulou in Fujian, China, characterized by its distinct building form and local culture is an outstanding representation of ecological building. From the perspective of ecological aesthetic, this research discusses the aesthetic factors of wind environment of Eryi Lou, the largest Tulou in Fujian. Starting from the GIS analysis on the overall environment, also assisted by MapInFo, this research further analyzes the external and internal wind environment of the Eryi Lou through site measurement of the buildings ventilation efficiency. Results showed that building form of Eryi Lou corresponded with topography and landform, as well as life wisdom of symbiosis with the environment and meets the requirements of ecological aesthetics criteria of both local characteristics and national character. The design of the major entrance with Feng Shui-oriented axis, as well as the design of courtyard in the quadrangle, circular corridors, and windows on the forth-storey are all intended for better cross-ventilation and heat dissipation. Such a design is a combination of aesthetics and human-based functional use, proving that Eryi Lou is an ecological building corresponding to the concept of ecological aesthetics, is an exemplar of symbiotic relationship between modern city development and environment.

Abstract: Under the background of global warming, carbon dioxide among natural refrigerants has attracted considerable attention as an alternative refrigerant. In the present study, experimental investigations of the fluid flow characteristic of supercritical CO₂ in a helically coiled tube with the inner diameter 9.0 mm, coil diameter 283 mm and coil pitch 32 mm were carried out. Both frictional pressure drop and friction factor were obtained under the pressure of 8.0 MPa, mass flux from 0 to 600 kg/m²s and inner heat flux from 0 to 20 kW/m². The results indicate that inner wall heat flux and mass flux had significant effects on fluid flow characteristics. The study provides experimental data that could be used for the design and development of more efficient exchangers for refrigeration conditioning, heat pump and some other systems.

Abstract: Decoration and fitment result in serious indoor air pollution in residential houses nowadays, furthermore, this kind of pollution can usually last for several years. The most effective way to eliminate indoor air pollution is to open the window to air the room at all seasons of the year. But compared to southern China weather conditions, there are frequently windy, dusty and great temperature differences days in Beijing especially around wintertime, causing indoor dust dispersion after ventilating though the window. People have to close the window in winter for years, making indoor air quality getting worse, which is quite harmful for the peoples physical and mental health. Aiming at above problems, a new kind of unpowered fresh air exchange component based on natural ventilation is proposed in this paper. A typical north-south permeability residential house, which means that there are opposite windows in both north and south walls to make draught forming more easily, in Beijing was taken for example. The authors studied the influences to air exchange effects and room temperature in different working conditions when adopting this kind of unpowered fresh air exchange components to ventilate and exchange air for 24 hours without cease, analyzed applicable conditions, influencing factors, installation height, installation height difference, and air exchange effects etc. of the unpowered fresh air exchange components. The simulating calculation using Computer Fluid Dynamics (CFD) software and experimental test were conducted.

Abstract: Individual air-conditioning system (IACS) can create an individual thermal environment control in a workroom which can contribute to save air-conditioning energy. In this study, we analyze the airflow circulation cell of the IACS with varied outlet port opening dimensions using the computational fluid dynamics (CFD) technique. We created an IACS, two workstations, lightings, and a cabinet in a 3-dimensional room. The fluid was assumed to be Newtonian, unsteady, and incompressible. We examined the effects of the outlet port opening on airflow circulation establishing process. Results will indicate the suitable outlet port opening for maintaining individual satisfied occupants’ requirements and improving energy saving potential.