This paper investigates the environmental impacts and energy benefits of the cultivation of Miscanthus (Miscanthus × giganteus Greef et Deu.), in order to initiate its use in sustainable household heating in the Republic of Serbia. Based on the analysis of available data regarding the use of agricultural machinery in Serbia, a Miscanthus supply chain is constructed and examined in detail, scrutinizing all relevant operations—from planting of rhizomes to thermal energy production. Results of the life cycle assessment identify the briquetting process as the most environmentally burdensome operation due to high electricity consumption and low productivity. It is concluded that an average yield of 23.5 t dry matter (d.m.) year−1 obtained from 1 ha of chernozem soil would have energy output:energy input (EO:EI) ratio of 51:1, and would release 365.5 gigajoules (GJ) of heat during combustion in a boiler. With this amount of energy, around 383 m2 of a free-standing family house in Serbia can be heated annually. The same amount of energy is obtained by the combustion of 22 t of lignite or 23 t of wood logs. The substitution of lignite and wood with Miscanthus briquettes would lead to significant reduction of CO2 equivalents (eq), SO2 eq, P eq, N eq, 1,4 dichlorobenzene (1,4-DB) eq, Non-methane volatile organic compound (NMVOC), PM10 eq and U235 eq emissions. This designates Miscanthus as a more sustainable energy solution for household heating. In instances where more modern agricultural machinery is used, emission reduction is higher, except for CO2 eq due to higher emission factors predicted for more powerful engines. Depending on Miscanthus’ annual yield, the replacement of set-aside land with Miscanthus plantations result in carbon (C) sequestration from 0.08 t C ha−1 year−1 to 0.91 t C ha−1 year−1. In a modern machinery scenario, C sequestration is only attainable when maximal Miscanthus yield is obtained. The combined use of machinery with different engine power is the best option for Miscanthus cultivation in Serbia.
This study investigates the influence of input values for building energy model parameters on simulation results, with the aim of improving the reliability and sustainability of energy performance assessments. Dynamic simulations were conducted in TRNSYS for three theoretical multi-residential buildings, varying parameters such as referent model dimensions, infiltration rates, envelope thermophysical properties, and interior thermal capacitance. The case study, based in Slovenia, demonstrates that glazing-related parameters, particularly the solar heat gain coefficient (g-value), exert the most significant influence—reducing the g-value from 0.62 to 0.22 decreased simulated heating (qH,nd) and cooling (qC,nd) demands by 25% and 95%, respectively. In contrast, referent dimensions for modeled floor area proved least influential. For Building III (BSF = 0.36), dimensional variations altered results by less than ±1%, whereas, for Building I (BSF = 0.62), variations reached up to ±20%. In general, lower shape factors yield more robust energy models that are less sensitive to input deviations. These findings are critical for promoting resource-efficient simulation practices and ensuring that energy modeling contributes effectively to sustainable building design. Understanding which inputs warrant detailed attention supports more targeted and meaningful simulation workflows, enabling more accurate and impactful strategies for building energy efficiency and long-term environmental performance.
For accelerating hypersonic vehicles, it is important to understand the effects of various factors on heat transfer deterioration. The heat transfer characteristics of supercritical n-decane with pyrolysis were numerically simulated inside a vertical tube. The effects of flow direction, mass-flow rate, heat flux, inlet temperature, and flight acceleration on the heat transfer characteristics were investigated. When the inlet temperature was relatively low or the fluid was decelerated vertically upward, a typical M-shaped velocity distribution was formed, indicating the heat transfer deterioration. Furthermore, the decrease in wall heat flux, as well as the increase in mass-flow rate, inlet temperature and flight acceleration in the same direction as the flow makes the heat transfer deterioration gradually disappear. Finally, a new relationship was established between the heat flux and the flight acceleration and inlet temperature to determine critical heat flux under which heat transfer deterioration developed in the upward flow.
Latent heat is commonly measured using Differential Thermal Analysis (DTA) or Differential Scanning Calorimetry (DSC) or calculated using software packages (Thermo-Calc). In this study, the DSC method was used to comprehensively evaluate the accuracy of calculated latent heat for a specific range of cast AlSiCu alloys, considering their solidification under different cooling conditions. The tests involved varying concentrations of two crucial alloying elements: wSi (5, 7, and 9%) and wCu (1, 2, and 4%). All selected alloys were analyzed under three distinct cooling/heating rates: 6, 10, and 50 °C/min. The Thermo-Calc method was used in this work to calculate the latent heats of the investigated alloys. The results obtained show good agreement between the measured and calculated values. The increase in silicon content in the investigated alloys from 4.85% to 9.85% resulted in the increase in latent heat from 407.6 kJ/kg to 467.5 kJ/kg. Higher cooling rates, such as 50 °C/min, resulted in a reduced latent heat release compared to slower rates such as 10 °C/min and 6 °C/min.