Abstract

Ammonia, a carbon-free fuel from renewable sources, faces low combustion efficiency in gas turbines. Converting it into hydrogen-rich gas improves efficiency. This study explores integrating ammonia-fed gas turbines with concentrated solar power (CSP), using solar energy to decompose ammonia into hydrogen-rich fuel on-site. Replacing ammonia with this fuel enhances thermal and combustion efficiency. The research evaluates operational parameters, showing a thermal efficiency increase of up to 3.5%. A thermodynamic analysis assesses efficiency and heat balance, while flame speed dependence on hydrogen-rich gas composition, pressure, temperature, and equivalence ratio is examined. Under gas turbine conditions, flame speeds reach 20–30 cm/s for a 1:3 ammonia-hydrogen blend. The findings demonstrate the potential of solar driven ammonia cracking to optimize gas turbine performance.

Abstract

Experiment investigation on the feasibility of chemical ignition method used in achieving a successful ISC process is conducted in this work, which the electrical heating method might not be a good selection due to the deep heavy oil reservoir. A longer wire connecting with the heating rod is needed and a greater electrical resistance would be generated combining with more heat release. Therefore, an accelerated thermal aging issues for the wire should be concerned. What is more, the water flooding and other enhanced oil recovery methods have been applied in this deep heavy oil reservoirs developing with edge and bottom water of Tuha oil field, and a poor performance is obtained. Hence, chemical ignition method is proposed and the composition of ignition materials are evaluated through the kinetic cell and the combustion tube experiments. The results indicate that the chemical ignition agent with a high-temperature oxidation reaction varying in the range of 120-170℃ is prone to a successful combustion tube. When the ambient temperature with an initial value of 120℃ is given, a successful ignition can be achieved with a slowly temperature rising rate, especially in its early stage. However, the temperature rise rate would be presented with a significant greater combining with an intense high temperature oxidation (HTO) process as the increasing air injection rate is performed with a higher ignition temperature value of 170 ℃. Then a successful ignition combining with a better oil recovery is obtained. Finally, the chemical ignition process was successfully verified to achieve stable expansion of the combustion chamber in three-dimensional large-scale model experiments. The results and recognition of this work can be a valuable reference for the application of chemical ignition in the development of medium to deep heavy oil reservoir..

Abstract

This paper develops a novel multi-objective optimization framework, capable of predicting the optimization of renewable energy integration from available sources in northern and remote regions, while considering energy supply, cost, greenhouse gas emissions (GHG), and social impacts. Wind turbines, photovoltaic (PV) panels, small modular reactors (SMRs), and geothermal systems, along with lithium-ion batteries, are modeled separately. Multi-objective evolutionary algorithms (MOEAs) are employed to systematically evaluate each technology from energy and cost to environmental and social impacts. Applied to Ellesmere Island, the optimal renewable deployment halves cost ($500𝑀 in lifetime savings), reduces carbon emissions by over 90%, and eases social disagreement from 53% to 36% compared to diesel grids. The solution is viable, provided a payback period of less than 6 years to recoup the higher initial capital costs.

Abstract

During natural gas hydrate (NGH) drilling and production, changes in reservoir temperature and pressure conditions, along with heat generated by drilling operations, can lead to partial or even uncontrolled hydrate dissociation. This phenomenon increases the risk of wellbore instability and jeopardizes drilling efficiency and safety. Hydrate dissociation inhibitors have thus emerged as critical components for stabilizing hydrate-bearing formations and mitigating drilling risks, thereby supporting efficient NGH extraction. However, current evaluation methods for NGH inhibitors predominantly focus on inhibiting hydrate formation, with relatively limited research addressing performance assessment of dissociation inhibitors. Based on a comprehensive literature review, this study first demonstrates the feasibility of using cyclopentane hydrate as a substitute for methane hydrate in evaluating dissociation inhibitor performance. An experimental protocol was designed accordingly to assess inhibitor efficacy using cyclopentane hydrate. Under this constructed evaluation framework, the equilibrium temperature of cyclopentane hydrate was measured at 6.73°C, and 0.7% lecithin solution effectively delayed dissociation for 53 minutes. These results validate the practicality and reliability of the proposed assessment methodology.

Abstract

Scenario-based approaches are widely used to explore long-term energy transitions under deep uncertainty. Integrated assessment and energy system models provide quantitative insights but often combine technological, policy, institutional, and social assumptions without checking their consistency, which can produce numerically coherent yet internally contradictory scenarios that weaken policy relevance. Cross-Impact Balance (CIB) analysis can serve as a front-end screening tool to identify internally consistent scenario configurations before quantitative modelling. Applications in energy and sustainability studies demonstrate that CIB reduces arbitrary assumption combinations, enhances transparency, and links qualitative narratives with quantitative inputs, thereby strengthening the reliability of scenario-based energy and climate policy analysis.

Abstract

The widespread success of deep reinforcement learning (DRL) is increasingly challenged by its substantial energy footprint, posing a significant obstacle to green artificial intelligence (AI) development. While some research has primarily focused on the energy efficiency of deep neural networks (DNNs), the unique energy consumption characteristics stemming from DRL’s interactive learning paradigm have been largely overlooked. This paper bridges this critical gap by introducing EnergyDRL, a fine-grained energy analysis framework that enables a precise attribution of energy consumption across the entire DRL workflow by decomposing the training loop into functionally distinct stages. Energy monitoring modules based on EnergyDRL are deployed across comprehensive experiments on benchmark tasks, yielding a crucial but frequently overlooked insight: agent-environment interaction, rather than neural network updates, constitutes the primary energy bottleneck. Quantitative investigations further reveal that hyperparameters, model size, and the balance between sampling and updating distinctly influence the energy consumption profile, which provides the empirical foundation for proposed strategies to develop energy-efficient DRL algorithms.

Abstract

To respond to global carbon neutrality goals and promote the sustainable transformation of the building industry, the application of Building-Integrated Photovoltaics (BIPV) is garnering significant attention. High-rise office buildings with glass curtain walls, as landmarks in metropolitan Central Business Districts (CBDs), consume substantial amounts of energy to maintain indoor environmental comfort. To address this issue, the integration of Double-skin Facades (DSF) with BIPV is considered promising, as it can generate clean electricity onsite while simultaneously enhancing the thermal performance of the building envelope and improving indoor environmental comfort.

This paper presents the development of a prototype for a double-skin BIPV facade applied to glass curtain walls, based on modular office units. The prototype incorporates both opaque and semi-transparent photovoltaic (PV) elements. It explores the impact of design parameters on the overall energy performance of the BIPV facade system and the indoor natural light environment. Design optimization is conducted using data obtained from simulations and outdoor experiments. Under conditions where the modular frame size and the area of opaque PV panels are the same, the power generated by the opaque PV in the baseline prototype accounts for approximately 54.7% of the total facade power. By rotating the opaque portion of the facade from the vertical surface by 60 degrees, the total power generation is more than doubled, with the opaque PV contributing over 75% to the total power output. In the closed system (Prototype 1), the surface temperature of the opaque PV is higher than that of the open system (Prototype 2), with an average of 1.19 and 1.26 times that of the baseline. However, the temperatures of the semi-transparent PV in these three prototypes are similar. Furthermore, the amount of side light entering the interior has a significant impact on indoor illuminance; removing the side cover plate results in an increase in indoor illuminance, around 193% to 212% of the pre-removal levels.

Abstract

Growing global concerns regarding carbon emissions and the demand for cleaner alternative energy sources have positioned methanol as a promising fuel for internal combustion engines, thanks to its hydrogen-rich composition, reduced carbon footprint, and favorable storage and transport properties. Nevertheless, methanol faces significant challenges in cold-start scenarios, largely due to its poor volatility and considerable heat absorption during evaporation. To tackle this issue, this research introduces a combined strategy integrating in-cylinder steam reforming of methanol with combustion enhanced by hydrogen enrichment. A finite-time thermodynamic framework was established to model the coupled combustion and reforming processes, taking into consideration critical variables including pressure ratio, air-fuel ratio, and rotational speed. Findings indicate that increased pressure ratio and air-fuel ratio contribute positively to engine performance, in contrast to engine speed, which shows a detrimental influence. Through multi-objective optimization, optimal operating parameters were identified as a pressure ratio of 20, an air-fuel ratio in the range of 13–15, and an engine speed between 1000 and 3000 rpm. This work aims to offer fundamental theoretical insights to guide and assist future endeavors in the design and refinement of methanol-fueled internal combustion engines.

Abstract

Building envelope retrofit strategies enable reducing cooling loads in warm climates and optimising energy use. However, these strategies may be tailored to specific building types and their effectiveness depends on the climatic conditions they operate under. This paper presents an open-source model to assess the effects of envelope retrofits under the climatic conditions of India. Using OpenModelica, an office building located at Delhi was modelled using real construction and occupancy data. The indoor heat gain through the building envelope was quantified for different retrofitting scenarios. Results show thermal insulation is more effective than phase change material in mitigating heat gain and can reduce the heat gain by up to 400 W in summer. The findings offer insights for sustainable cooling, whereas the developed model offers an open-source tool to quantify cooling demand in office buildings.

Abstract

Decarbonisation of heat in residential buildings remains a critical challenge in achieving net-zero energy goals. This paper presents a dynamic simulation and performance evaluation of a hybrid energy system integrating photovoltaic-thermal (PVT) solar collectors with a ground-source heat pump (GSHP) to meet the space heating demand of a terraced house. The system was modelled using TRNSYS, enabling detailed hourly performance analysis under varying weather and load conditions. Borehole heat exchangers, thermal energy storage and the control logic are explicitly modelled to reflect realistic operational behaviour. Results show the system’s ability to deliver demand-side flexibility, reduce grid dependency and enhance seasonal performance. The coupled PVT-GSHP system achieves a stable coefficient of performance while maintaining acceptable indoor thermal comfort. This study contributes to the growing evidence supporting hybrid low-carbon technologies for residential heating solutions.