Search Results (24)

Seawater electrolysis offers a sustainable route for large-scale, carbon-neutral hydrogen production, but its industrial application is limited by the poor efficiency and durability of current electrocatalysts under high current densities. Herein, we synthesized ultrasmall Pt nanoclusters uniformly anchored on FeCoNi phosphide nanosheet arrays, forming a composite catalyst with outstanding hydrogen evolution reaction (HER) performance in alkaline seawater. The catalyst achieves an ultralow overpotential of 17 mV at −10 mA cm⁻², far surpassing commercial Pt/C, and stably delivers industrial-level current densities up to 2000 A m⁻² for over 2400 h with minimal voltage degradation and low energy consumption (4.16 kWh/Nm³ H₂). X-ray photoelectron spectroscopy revealed strong interfacial electronic interactions between Pt and Fe/Co species, involving electron transfer from Pt that modulates its electronic structure, weakens hydrogen adsorption, and enhances both HER kinetics and Pt dispersion. This work presents a scalable and robust catalyst platform, bridging the gap between laboratory research and industrial seawater electrolysis for green hydrogen production. Full article

Waste heat utilization in fuel cell vehicles represents a critical technology for enhancing overall energy utilization efficiency and environmental adaptability, which reduces auxiliary heating consumption, extends driving range, and minimizes thermal management parasitic losses, holding significance for promoting application of fuel cell commercial vehicles. This study investigates a 49-ton fuel cell heavy-duty truck equipped with waste heat recovery capability, conducting vehicle energy flow experiments under multiple ambient temperatures (including 7 °C, $-7$ °C and $-25$ °C extreme cold conditions), varying load conditions, and waste heat recovery mode switching, with focused analysis on the energy consumption and temperature response of the waste heat recover critical components, to evaluate the energy utilization of fuel cell waste heat. Experimental results demonstrate the substantial impact of waste heat recovery function on the proportion of the warm air positive temperature coefficient (PTC) energy consumption on total energy consumption, showing that deactivating waste heat recovery increased the PTC energy consumption obviously. Besides, activating the waste heat recovery function contributes to elevated the stack radiator outlet temperature under low-temperature operating conditions. Full article

Personalized thermal comfort (PTC) systems aim to satisfy the individual thermal preferences of occupants rather than relying on average comfort indices. With the growing emphasis on sustainability and reducing energy consumption in buildings, energy efficiency has become a critical factor in the design and selection of PTC systems. While the development of PTC tools has accelerated in the last decade, selecting the most appropriate system remains a challenge due to the dynamic, uncertain, and multi-dimensional nature of the decision-making process. This study introduces a novel application of the KEMIRA-M multi-criteria decision-making (MCDM) method to identify the optimal PTC system for university office buildings—an area with limited prior investigation. A case study is conducted in a naturally ventilated office space located in a temperate climate zone. Eight distinct PTC alternatives are evaluated, including data-driven HVAC systems, wearable devices, and localized conditioning units. Six key criteria are considered: estimated energy consumption, capital cost, indoor and outdoor space requirements, system complexity, mobility, and energy efficiency. The results indicate that wearable wristbands, which condition the occupant’s carpus area, offer the most balanced performance across criteria, while radiant ceiling/floor systems perform the poorest. Energy efficiency plays a crucial role in this evaluation, as it directly impacts both the operational cost and the environmental footprint of the system. The study’s findings provide a structured and adaptable framework for HVAC engineers and designers to integrate PTC systems into occupant-centric and energy-efficient building designs. Full article

In cold environments, traditional independent thermal management systems heavily rely on inefficient Positive Temperature Coefficient (PTC) heaters, which exacerbate range anxiety in vehicles. In this study, an energy management-based control strategy for an integrated thermal management system (ITMS) designed for hybrid electric vehicles (HEVs) is proposed. By coupling the four thermal flow circuits of the entire vehicle and integrating driving modes with heating demands, this strategy achieves full vehicle-level integrated control. Through optimizing the distribution and utilization of heat within the vehicle, this enhances the heating performance of the air source heat pump. The simulation results demonstrate that the proposed strategy significantly reduces the power consumption of the heat pump and improves heating efficiency for both the battery and the cabin. By utilizing waste heat from the motor and the engine, the ITMS increases the heating capacity of the heat pump, particularly in low-temperature environments. Compared to traditional thermal management systems, the ITMS control strategy achieves substantial improvements in both heating time and energy efficiency. Specifically, the system reduces battery heating time by 55.94% and enhances the overall heating performance of the vehicle. Furthermore, the strategy reduces fuel consumption by 5.18%, demonstrating its potential to improve the energy efficiency of HEVs in cold climates. Full article

The energy consumption of data center cooling systems is rapidly increasing, necessitating urgent improvements in cooling system performance. This study investigates a pump-driven two-phase cooling system (PTCS) utilizing a parallel-flow heat exchanger (PFHE) as an evaporator, positioned at the rear of server cabinets. The findings indicate that enhancing the vapor quality at the PFHE outlet improves the overall cooling performance. However, airflow non-uniformity induces premature localized overheating, restricting further increases in vapor quality. For PFHEs operating with a two-phase outlet condition, inlet air temperature non-uniformity has a relatively minor impact on the cooling capacity but significantly affects the drop in pressure. Specifically, higher upstream air temperatures increase the pressure drop by 7%, whereas higher downstream air temperatures reduce it by 7.7%. The implementation of multi-pass configurations effectively mitigates localized overheating caused by airflow non-uniformity, suppresses the decline in cooling capacity, and enhances the operational vapor quality of the cooling system. Full article

Ethenzamide (2-ethoxybenzamide), besides acetylsalicylic acid, is one of the mostly used salicylic acid derivatives in pharmaceuticals. It has analgesic and anti-inflammatory effects that originate from the inhibition of cyclooxygenase (COX-1) activity, thus blocking prostaglandin synthesis. In this work, efficient and eco-friendly methods were developed for the synthesis of ethenzamide via the O-alkylation reaction of salicylamide. The reactions were carried out under conventional conditions in a solvent-free system using variant solvents and different phase transfer catalysts (PTC) in the presence of microwave radiation or ultrasonic conditions. It was shown that in solvent-free conditions using TBAB as a catalyst, ethenzamide can be obtained within 15 min at 80 °C with 79% yield. Meanwhile, using microwave radiation under the same conditions, the reaction time can be shortened to 90 s with 92% yield. Notably, high yields can be achieved under PTC in water (or organic solvent-free) conditions using microwave radiation (2 min, 94%) or ultrasound (10 min, 95% efficiency). The studies prove that the PTC synthesis process of ethenzamide can be conducted under mild conditions, with a shorter reaction time and remarkably lower energy consumption in comparison to conventional processes, thus actualizing “green chemistry” for practical ethenzamide preparation. Full article

The photo-thermochemical cycle (PTC) for water splitting offers a sustainable method for hydrogen production by efficiently utilizing solar energy. This study explored the use of CeO₂ as a catalyst in the PTC system to enhance hydrogen yield. A nanostructured CeO₂ catalyst was synthesized via the sol-gel method, achieving an H₂ yield of 8.35 μmol g⁻¹ h⁻¹. Stability tests over five cycles showed consistent yields between 7.22 and 8.35 μmol g⁻¹ h⁻¹. Analysis revealed that oxygen vacancies (V_Os) increased after the photoreaction and depleted during the thermal reaction, which aligns with the expected PTC mechanism for hydrogen production. Single-factor experiments highlighted that photoreaction duration mainly influenced V_Os generation, while thermal duration and temperature impacted V_Os consumption and intermediate reaction rates. A response surface methodology (RSM) model predicted optimal conditions for maximum H₂ yield (8.85 μmol g⁻¹ h⁻¹) with a photoreaction duration of 46.6 min, thermal duration of 45.4 min, and thermal temperature of 547.2 °C. Full article

In some scenarios, electric heavy-duty trucks with battery swapping mode (ETBSm) are more cost-effective than battery charging mode. The viability of battery swapping stations is contingent upon the operational requirements and range capabilities of the ETBSm. Low temperatures have the effect of reducing the range of the ETBSm, thereby creating difficulties for battery swapping. This article proposes the use of motor waste heat recovery (MWHR) to heat batteries, which would improve range. A number of subsystem models have been established, including the ETBSm, battery, motor, and thermal management system (TMS). The calibration of battery temperature and motor efficiency is achieved with a model error of less than 5%. Comparison of performance, such as temperature, energy consumption, and range, when using only positive temperature coefficient (PTC) heating and when using both PTC heating and motor waste heat. The results indicate a 15% increase in the rate of rise in battery temperature and a 10.64 kW·h reduction in energy consumption under Chinese heavy-duty vehicle commercial vehicle test cycle (CHTC) conditions. Then, the motor waste heat percentage, energy consumption, and range are analyzed at different ambient temperatures. At an ambient temperature of −20 °C, −10 °C, and 0 °C, the percentage of the motor waste heat is 32.1%, 35%, and 40.5%; when 75% of the state of charge (SOC) is consumed, the range is improved by 6.55%, 4.37%, and 4.49%. Additionally, the effect of the PTC heater on temperature characteristics and power consumption is investigated by changing the target temperature of the coolant at the battery inlet. In accordance with the stipulated conditions of an ambient temperature of −20 °C and a target coolant temperature of 40 °C at the battery inlet, the simulation results indicated a battery temperature rise rate of 0.85 °C/min, accompanied by a PTC power consumption of 15.6 kW·h. This study demonstrates that as the ambient temperature increases, the utilization of motor waste heat becomes more effective in reducing PTC heating power consumption. At the lowest ambient temperature tested, the greatest improvement in driving range is observed. It is important to note that while an increase in the target heating temperature of the PTC helps to raise the battery temperature more rapidly, this is accompanied by a higher energy consumption. This article provides a reference for the ETBSm with MWHR. Full article

In a conventional automotive manufacturing plant, the paint shop alone can represent 36% of the total energy consumption, making it the most demanding area in terms of electricity and fossil fuel energy consumption. This study explores the possibility of decentralizing the production of electrical power and heat simultaneously, using an Organic Rankine Cycle (ORC) system integrated with a Parabolic Trough Collector (PTC) in a paint shop. To date, no similar system has been explored or implemented by the automotive industry. To increase the efficiency of the integrated system, wasted heat generated during the paint manufacturing process is recovered and used to pre-heat the organic fluid in the ORC system. A 4E analysis (Energy, Exergy, Economic, and Environmental) is conducted to determine the practical viability of the proposed system. When applied to the southern region of the USA, this system’s installed capacity is projected to be 11 times higher than the two unique SORC pieces of equipment currently running in Louisiana and Florida. The goals are to reduce the reliance on external primary energy sources and decrease the carbon emission footprint from production activity. The system is evaluated for a location in Alabama, USA. The designed SORC, using toluene, can produce 712.2 kW_el net and 13,132 kg/h of hot water, with an overall energy efficiency of 31.02%; exergy efficiency of 34.23; and ORC efficiency of 27.70%. This leads to an electrical energy saving of 5.9% for the manufacturing plant. The regenerative thermal oxidizer (RTO) heat exchanger, the secondary heat source of the system, has the highest exergy destruction—3583 kW. The system avoids the emission of 4521 tCO₂ per year. A payback period of 10.16 years for the proposed system is estimated. Considering a planning horizon of 10 years, the investment in the system is also justified by a benefit–cost analysis. Full article

Battery electric vehicle (BEV) air conditioning systems often use positive temperature coefficient (PTC) heaters to heat the passenger compartment. The heating process consumes a lot of energy in low-temperature environments, which seriously affects the driving range and user experience. This study aims to reduce the low-temperature energy consumption of the air conditioning system and improve energy efficiency through an innovative optimization method. In this study, the energy consumption composition of the air conditioning system was analyzed, and the goal of minimizing the sum of the total power consumption of the PTC heater and the blower was determined, while the efficiency characteristic of the blower was considered at the same time. The relationship between the average temperature of the passenger compartment measurement points and the PTC power and airflow rate was studied by combining experiments and numerical simulations, and the alternative operating conditions that met the temperature requirement were determined. On this basis, the total power consumption of the air conditioning system was analyzed and optimized. The results show that PTC power, airflow rate, and blower efficiency all have an important influence on the total power consumption of the air conditioning system. The optimized scheme could reduce the theoretical total power from 1315.32 W of the original scheme to 1246.83 W, and the actual total power from 1350.05 W of the original scheme to 1326.56 W, with reductions of 5.21% and 1.74%, respectively. The low-temperature energy consumption optimization method for the BEV air conditioning systems proposed in this study is instructive for the selection of blowers and the design of control strategies for air conditioning systems. Full article

Electric vehicles can effectively make use of the time-of-use electricity price to reduce the charging cost. Additionally, using grid power to preheat the battery before departure is particularly important for improving the vehicle mileage and reducing the use cost. In this paper, a dynamic programming algorithm is used to optimize the battery AC (Alternating Current) charging–preheating strategy to minimize the total cost of battery charging and preheating, with the charging current and battery preheating power consumption as the control variables. The cost difference between the optimized control strategy and the conventional preheating strategy was analyzed under different ambient temperatures (−20~0 °C) and different target travel times (7:00~12:00). The simulation results show that the optimized control strategy makes the state of charge (SOC) and temperature of the battery reach the set value at the user’s target departure time, and the total cost of the grid is the lowest. Compared with the conventional preheating strategy, the optimized control strategy can utilize the power grid energy in the valley price area and reduce the opening time of the positive temperature coefficient (PTC) heater in the flat and the peak price zones. Furthermore, the cost utilization rate can reach 18.41~73.96%, and the cost-saving effect is significant. Full article

Buildings represent approximately two-thirds of the overall energy needs, mainly due to the growing energy consumption of air conditioning and water heating loads. Hence, it is necessary to minimize energy usage in buildings. Numerous research studies have been carried out on evacuated tube solar collectors, but to our knowledge, no previous study has mentioned the combination of an evacuated tube solar collector with a parabolic trough collector and a helical coil heat exchanger. The objective of this paper is to evaluate the thermal behavior of an innovative evacuated tube solar collector (ETSC) incorporated with a helical coil heat exchanger and equipped with a parabolic trough collector (PTC) used as a domestic water heater. To design the parabolic solar collector, the Parabola Calculator 2.0 software was used, and the Soltrace software was used to determine the optical behavior of a PTC. Moreover, an analytical model was created in order to enhance the performance of the new model of an ETSC by studying the impact of geometric design and functional parameters on the collector’s effectiveness. An assessment of the thermal behavior of the new ETSC was performed. Thus, the proposed analytical model gives the possibility of optimizing ETSCs used as domestic water heaters with lower computational costs. Furthermore, the optimum operational and geometrical parameters of the new ETSC base-helical tube heat exchanger include a higher thermal efficiency of 72%. This finding highlights the potential of the heat exchanger as an excellent component that can be incorporated into ETSCs. Full article

In the present research, the energy flow of electric vehicle batteries under different environmental temperatures was experimentally examined in a climate chamber. The energy flow characteristics, energy loss conditions, and the critical components’ operating conditions and working efficiency under different environmental temperatures were comparatively analyzed. The test results show that the environmental temperature has a profound impact on an electric vehicle’s performance and the critical components’ working conditions. The driving mileage of the tested vehicle at −7 °C, 23 °C, and 35 °C was found to be 162.89 km, 256.09 km, and 198.69 km, respectively. The environmental temperature does not have much effect on the loss of the motor and motor control unit under driving conditions, and the proportion of those at different temperatures is in all cases about 18%. The battery-recycled energy at 23 °C under braking conditions is much higher than that at −7 °C and 35 °C, leading to a longer driving range. The power battery pack thermal transfer loss at −7 °C is much greater than that at 23 °C and 35 °C due to the low charging and discharging efficiency and the high energy consumption required to warm up the battery at a low environmental temperature. The compressor energy consumption accounts for a large proportion in both braking and driving conditions at 35 °C, and the proportions are 15.25% and 12.41%, respectively. The battery state-of-charge drops the fastest at −7 °C, followed by 35 °C, due to the differences in the power demands of air conditioning, warm air positive temperature coefficient (PTC), and battery PTC in high- and low-temperature environments. The working condition of the front motor under driving conditions at 35 °C is the most severe and leads to the lowest working efficiency. Full article

The use of solar energy for cooling processes is advantageous for reducing the energy consumption of conventional air-conditioning systems and protecting the environment. In the present work, a solar-powered cooling system with parabolic trough collectors (PTC) and a phase change material (PCM) tank is numerically investigated in the arid climates of Saudi Arabia. The system contains a 160-kW double-effect absorption chiller powered by solar-heated pressurized water as a heat transfer fluid (HTF) and a shell and tube PCM as a thermal battery. The novelty of this paper is to investigate the feasibility and the potential of using a PTC solar field coupled to a PCM tank for cooling purposes in arid climates. The numerical method is adopted in this work, and a dynamic model is developed based on the lumped approach; it is validated using data from the literature. The functioning of the coupled system is investigated in both sunshine hours (charging period) and off-sunshine hours (discharging period). The PTC area in this work varies from 200 m² to 260 m² and the cooling capacity of the chiller ranges from 120 kW to 200 kW. Obtained results showed that the 160-kW chiller is fully driven by the 240 m²-solar PTC during the charging period and about 23% of solar thermal energy is stored in the PCM tank. It was demonstrated that increasing the PTC area from 220 m² to 260 m² leads to a reduction in the PCM charging time by up to 45%. In addition, it was found that an increase in the cooling loads from 120 kW to 200 kW induces a decrease in the stored thermal energy in the PCM tank from 450 kWh to 45 kWh. During the discharging period, the PCM tank can continue the cooling process with a stable delivered cooling power of 160 kW and an HTF temperature between 118 °C and 150 °C. The PCM tank used in the studied absorption chiller leads to a reduction of up to 30% in cooling energy consumption during off-sunshine hours. Full article

An investigation was conducted to determine the effects of operating parameters for various electrode types on hydrogen gas production through electrolysis, as well as to evaluate the efficiency of the polymer electrolyte membrane (PEM) electrolyzer. Deionized (DI) water was fed to a single-cell PEM electrolyzer with an active area of 36 cm². Parameters such as power supply (50–500 mA/cm²), feed water flow rate (0.5–5 mL/min), water temperature (25−80 °C), and type of anode electrocatalyst (0.5 mg/cm² PtC [60%], 1.5 mg/cm² IrRuOx with 1.5 mg/cm² PtB, 3.0 mg/cm² IrRuOx, and 3.0 mg/cm² PtB) were varied. The effects of these parameter changes were then analyzed in terms of the polarization curve, hydrogen flowrate, power consumption, voltaic efficiency, and energy efficiency. The best electrolysis performance was observed at a DI water feed flowrate of 2 mL/min and a cell temperature of 70 °C, using a membrane electrode assembly that has a 3.0 mg/cm² IrRuOx catalyst at the anode side. This improved performance of the PEM electrolyzer is due to the reduction in activation as well as ohmic losses. Furthermore, the energy consumption was optimal when the current density was about 200 mA/cm², with voltaic and energy efficiencies of 85% and 67.5%, respectively. This result indicates low electrical energy consumption, which can lower the operating cost and increase the performance of PEM electrolyzers. Therefore, the optimal operating parameters are crucial to ensure the ideal performance and durability of the PEM electrolyzer as well as lower its operating costs. Full article