For the safe utilization and management of hydrogen energy within a fuel-cell room in a hydrogen-fueled house, an explosion test was conducted to evaluate the potential hazards associated with hydrogen accident scenarios. The overpressure and heat radiation were measured for an explosion accident at distances of 1, 2, 3, 5, and 10 m for hydrogen–air mixing ratios of 10%, 25%, 40%, and 60%. When the hydrogen–air mixture ratio was 40%, the greatest overpressure was 24.35 kPa at a distance of 1 m from the fuel-cell room. Additionally, the thermal radiation was more than 1.5 kW/m², which could cause burns at a distance of 5 m from the hydrogen fuel-cell room. Moreover, a thermal radiation in excess of 1.5 kW/m² was computed at a distance of 3 m from the hydrogen fuel-cell room when the hydrogen–air mixing ratio was 25% and 60%. Consequently, an explosion in the hydrogen fuel-cell room did not considerably affect fatality levels, but could affect the injury levels and temporary threshold shifts. Furthermore, the degree of physical damage did not reach major structural damage levels, causing only minor structural damage.

Hydrogen, which has a high energy density and does not emit pollutants, is considered an alternative energy source to replace fossil fuels. Herein, we report an experimental study on hydrogen leaks and ventilation methods for preventing damage caused by leaks from hydrogen fuel cell rooms in homes, among various uses of hydrogen. This experiment was conducted in a temporary space with a volume of 11.484 m³. The supplied pressure, leak-hole size, and leakage amount were adjusted as the experimental conditions. The resulting hydrogen concentrations, which changed according to the operation of the ventilation openings, ventilation fan, and supplied shutoff valve, were measured. The experimental results showed that the reductions in the hydrogen concentration due to the shutoff valve were the most significant. The maximum hydrogen concentration could be reduced by 80% or more if it is 100 times that of the leakage volume or higher. The shutoff valve, ventilation fan, and ventilation openings were required to reduce the concentrations of the fuel cell room hydrogen in a spatially uniform manner. Although the hydrogen concentration in a small hydrogen fuel cell room for home use can rapidly increase, a rapid reduction in the concentration of hydrogen with an appropriate ventilation system has been experimentally proven.

An inert gas such as nitrogen is used as an extinguishing agent to suppress unexpected fire in places such as computer rooms and server rooms. The gas released with high pressure causes noise above 130 dB. According to recent studies, loud noise above 120 dB has a strong vibrational energy that leads to a negative influence on electronic equipment with a high degree of integration. In this study, a basic fire-extinguishing nozzle with absorbent was selected as the reference model, and numerical analysis was conducted using the commercial software, ANSYS FLUENT ver. 18.1. A total of 45 experiment points was selected using the design of experiment (DOE) method. An optimum point was derived using the response surface method (RSM). Results show that the vibrational energy of the noise was reduced by minimizing the turbulence kinetic energy. Pressure and velocity distributions were calculated and graphically depicted with various absorbent configurations.

This study investigates annual performance of the hybrid energy system with geothermal and solar heat sources for hot water, heating and cooling of a residential house in South Korea. A small-scale hybrid-renewable energy system (H-RES) consists of a geothermal heat pump for heating and cooling, solar collectors for hot water, a gas fired backup boiler, and incidental facilities. All pipelines are designed for heat flow between the modules such as storage tank, heat production units, and radiators. Also, all systems automatically operated by the integrated sensing and control system. The average coefficient of performance of geothermal module during cooling and heating seasons is evaluated as about 4.1 and 3.5, respectively. Solar fraction for hot water is calculated as over 54%. And annual energy consumption of the H-RES is estimated as much as about 40% of conventional energy systems.

Erosion in piping structures poses a significant challenge for oil industries as the conveyance of solid particles leads to operational malfunctions and structural failures affecting the overall oil plant operation. Conventional oil recovery methods have historically dominated, while in response to the challenges imposed by declining conventional oil production, the global shift towards non-conventional methods necessitates a reevaluation of erosion mitigation strategies due to increased piping infrastructure. Therefore, in this study research has been conducted to reduce erosion and optimize the piping structure. Variables impacting the erosion in piping were investigated from the literature, and simulation cases were made based on the impacted variables. Computational Fluid Dynamics (CFDs) analysis was performed using the Discrete Phase Model (DPM) to determine the erosion wear rate in each simulation case; based on the CFD results, variables with low Turbulent Dissipation Rates (TDRs) and Erosion Rates (ERs) were determined, and the optimized piping structure was designed. As a result, the optimized piping structure showed an 80% reduction in the turbulent dissipation rate and a 99.2% decrease in the erosion wear rate. These findings highlight a substantial improvement in erosion control, ensuring the safety and longevity of piping structures in oil plant operations.