The insufficiency of energy supply and availability remains a significant global energy challenge. This work proposes a novel approach to addressing global energy challenges by testing the supercritical property and conversion of low-temperature thermal heat into useful energy. It introduces a combined-cascade steam-to-steam trigeneration cycle integrated with vapour absorption refrigeration (VAR) and district heating systems. Energetic and exergetic techniques were applied to assess irreversibility and exergetic destruction. At a gas turbine power of 26.1 MW, energy and exergy efficiencies of 76.68% and 37.71% were achieved, respectively, while producing 17.98 MW of electricity from the steam-to-steam driven cascaded topping and bottoming plants. The cascaded plant attained an energetic efficiency of 38.45% and an exergy efficiency of 56.19%. The overall cycle efficiencies were 85.05% (energy) and 77.99% (exergy). More than 50% of the plant’s lost energy came from the combustion chamber of the gas turbine. The trigeneration system incorporated a binary NH₃–H₂O VAR system, emphasizing its significance in low-temperature energy systems. The VAR system achieved a cycle exergetic efficiency of 92.25% at a cooling capacity of 2.07 MW, utilizing recovered waste heat at 88 °C for district hot water. The recovered heat minimizes overall exergy destruction, enhancing thermal plant performance.

Thermoelectric generators are solid-state devices that convert heat into electricity using the Seebeck effect, when there is a temperature difference across a thermoelectric material. This research designed an experimentally tested a thermoelectric hot air generator using sixteen SP1848-27145 modules in two parallel strings. The system consists of a biomass combustion chamber, hot air exhauster, hot and cold side heat exchangers. Voltage, current and temperatures in the combustion chamber, hot air heat exhauster, hot side heat exchanger and cold side heat sink were measured. The hot air exhauster, hot side heat sink and cold side maximum temperatures are 178.3°C, 69.2°C and 44.5°C respectively yielding an open circuit voltage of 64 V and current of 1.99 A in the course of the experiment. The thermal performance of the designed hot air exhauster, hot side heat exchanger and cold side heat were simulated using ANSYS Fluent, for pictorial representation of their temperature contours.

This study investigates carbon black (CB) production challenges, including high energy usage and waste of heat sources, by proposing a waste heat energy recovery concept to increase the sustainability of this energy‐intensive and environmentally impactful process. The research involves a novel integration of a steam power plant (STP) with an industrial CB plant (CBP) using Aspen Plus simulation software. Comparative exergetic performance analyses of the system were conducted with this tool, while the Engineering Equation Solver (EES) was used to evaluate the exergoeconomic modelling of the plant. Additionally, environmental sustainability indicators were determined. The integrated plant system delivered CB capacity of 1817 kg/s, converted 98.03% of CB feedstocks with a purification value of 99.25% and produced 195 MW of electricity, significantly improving plant efficiency. The overall energy and exergy efficiencies for the integrated system are computed as 98.75% and 80.40%, respectively, with the STP contributing to the overall plant improvement. About 50% of the produced exergy was destroyed, with the CB combustor accounting for 48% of the combined plant exergetic destruction. Despite a substantial waste–exergy ratio from CBP, the integration of the STP increased the system’s exergetic sustainability index (ESI) by 18%. The exergoeconomic analysis highlighted the highest cost of destruction in the combustor and evaluated the evaporator as the least exergoeconomic factor driver. Components with potential exergetic and cost destruction improvements were identified. In conclusion, integrating power generation units with CB production plants can markedly reduce thermal heat waste in the CBP and enhance integrated plant environmental performance.

Thermoelectric refrigeration achieves cooling through Peltier and Seebeck effect. Heat sinks attached to the hot and cold sides of the thermoelectric module help to efficiently dissipates and absorb heat. This research modelled the temperature profile across a heat sink and its optimization for a thermoelectric refrigeration application. Simulation was carried out using MATLAB to visualize the performance of the heat sink. The optimization was done using FMINCON in MATLAB by setting upper and lower bounds to satisfy space and volume requirement. The optimum values for the hot and cold heat sink geometry obtained using FMINCON tool in OPTIMTOOL box in MATLAB, yields number of fins as 10, fin spacing as 0.003m, the fin thickness as 0.002m and fin length as 0.015m with an optimum temperature of -0.8639.

This research centered on the design, simulation and testing of a solar thermoelectric refrigerator. Mathematical models of the system were derived and solved using MATLAB to predict the performance of the refrigerator at various operating con...

Economic and technical factors often force players in the oil and gas sectors to abandon oil wells with significant but minimal energy contents. To promote energy efficiency, efforts are ongoing to explore viable means of recovering such residual energy, basically as geotherms, for power generation. However, there are sparse studies in the literature that assess the exergo-environmental sustainability potentials of power generation from ORC using abandoned oil wells as the primary energy source, thereby necessitating this study. The exergetic sustainability and exergo-environmental performance of non-recuperative and recuperative organic Rankine cycle (ORC) plants were assessed in this study for the production of electricity from abandoned oil wells. The geomechanical properties of a typical oil well in Nigeria were employed as inputs into an established COMSOL model to determine the thermal profile of the heat source. For the ORC plant, the mass, energy, and exergy balance equations defined by the Thermodynamics laws were implemented in MATLAB. Also, MATLAB was adopted for computing the exergetic sustainability and exergo-environmental metrics for the individual components and the entire system. Results showed that the condenser exhibited the least exergo-environmental sustainability for both ORC schemes assessed, meaning that it contributed the most to energy wastages among the system components. Furthermore, results showed that the exergo-environmental impact rates of the condenser are highest in both cases. Generally, results showed that the inclusion of a recuperator would improve the exergy-based environmental sustainability of the ORC plant. Specifically, the overall rate of exergo-environmental impact would decrease from around 86 Pt/h to about 76 Pt/h, amounting to approximately 13% decrease.