Large space circular coal storage dome (LSCCSD) offers an environmental and dependable alternative to open stockpiles, and it has been consequently widely applied in China. However, due to the lack of scientific guidelines, its natural ventilation performance is lower than expected. Natural ventilation potential strongly depends on the roof geometry and opening mode, which have not yet been investigated for LSCCSD. This paper presents a detailed evaluation of the impact of dome geometry (rise span ratio), opening height, and opening modes on the ventilation performance of LSCCSD. The evaluation is based on computational fluid dynamics (CFD) methods and is validated by available wind tunnel testing. We employed three evaluation indicators, which are wind pressure coefficient, effective ventilation rate, and wind speed ratio. The results demonstrate that the rise span ratio has a significant effect on the wind pressure difference and the effective ventilation rate increases by approximately 9%-42% with a single-annular opening. When double-annular openings are set in a strong positive pressure zone, the effective ventilation rate increases by 100% and the average wind speed ratio increases by 50%. When it is compared with single one with similar opening height, the effective ventilation rate increases by 25%. The optimum natural ventilation performance for LSCCSD is achieved at a rise span ratio of 0.37. In addition, the lateral middle opening is kept higher than the ridge top of the coal pile. The proposed evaluation approach and design parameters provided instructive information in the building design and ventilation control for LSCCSDs.

In radiant floor systems, the distribution of the floor surface temperature, which can be used to determine the mean temperature and the lowest/highest temperature of the floor surface, is an important parameter. The mean temperature of the floor surface determines cooling/heating capacity and indoor thermal comfort. The lowest surface temperature, which considers the dew point in an indoor environment, is a crucial factor in the prevention of condensation on a floor surface. The highest surface temperature is typically considered for local thermal comfort. In this paper, an analytical solution for heat transfer in a multilayer floor structure of a radiant floor system is proposed based on the analysis of the heat transfer process of a multilayer floor, equivalent thermal resistance and separation of variables method. The corresponding formulas are derived to estimate the distribution of floor surface temperature. The calculation results are validated by experiments. The calculation and experimental results show good accordance. The absolute error between the calculation and experimental results for floor surface temperature is within 0.3ºC. A method for the calculation of the dimensionless temperature of the floor surface, which can be used for radiant heating and cooling systems, is provided. Using this proposed method, the distribution of floor surface temperature and the influence of floor structure parameters on the thermal performance of floors can be estimated and analyzed.