Cleaner Energy Systems最新文献

Activation of heat pump flexibilities is a viable solution to support balancing the grid via Demand Side Management measures and fulfill the need for flexibility options. Aggregators as interface between prosumers, distribution system operators and balance responsible parties face the challenge due to data privacy and technical restrictions to transform prosumer information into aggregated available flexibility to enable trading thereof. Thereby, literature lacks a generic, applicable and widely accepted flexibility estimation method for heat pumps, which incorporates reduced sensor and system information, system- and demand-dependent behaviour. In this paper, we adapt and extend a method from literature, by incorporating domain knowledge to overcome reduced sensor and system information. We apply data of five real-world heat pump systems, distinguish operation modes, estimate power and energy flexibility of each single heat pump system, proof transferability of the method, and aggregate the flexibilities available to showcase a small HP pool as a proof of concept.

Studies focusing on reducing trade-related carbon footprint by consolidating institutional quality are not much in the literature. This study examines the role of institutional quality and green trade on carbon emissions. The empirical findings are based on generalised method of moments and 45 African countries spanning the period of 2008 to 2020. The initial findings revealed that institutional quality has a neutral impact on carbon emissions but trade openness increases it. However, strengthening institutional quality towards green trade reduces carbon emissions. Precisely, strengthening institutional quality towards green trade by 1% will have a joint effect of reducing carbon emissions by 0.04%. The policy implication is that clean trade can be achieved by strengthening the region's institutions which subsequently promote environmental sustainability.

Methane emission modelling is essential for predicting landfill gas emissions and recovery, including sizing the landfill gas collection system. This study presents a developed methane emission model which can be replicated globally. The steps of model development and model equation are highlighted. The output from the developed model shows an average methane generation rate of around 8.06 m³/h in 1997 to about 16.17 m³/h in 2021. The results of the developed model have been critically addressed, and a comparison of the output is discussed with other models. The simulation done using the Monte Carlo approach shows a maximum deviation of around 18% from the developed model, validating the accuracy of the developed model. The findings of this study will serve as the basis for the development of a more robust LFG model for Indian as well as global landfills for methane recovery.

This paper investigates the operation and control of smart inverters (SI) for solar and solar-plus-storage systems with an emphasis on Volt-VAR Control (VVC) at solar interconnections. The paper provides techno-economic recommendations for both normal-size and oversized solar inverters equipped with VVC. The objective is to minimize the voltage violations, and active power curtailment by providing reactive power support to the grid while the IEEE 1547-2018 standards are satisfied. Moreover, a collaborative VVC is tested where a battery storage system is paired with the solar facility which is becoming a popular configuration to enhance energy resilience in communities. An unbalanced distribution network is modeled based on a modified IEEE 13-bus system to which three 700 kW solar PV plants are connected through smart inverters. Solar data from the University of Louisiana’s 1.1 MW solar farm is used and grouped into 28 clusters. Those clusters represent a 2-year period with 15-min granularity. Typhoon HIL 402 real-time simulator is utilized for modeling and verifying the proposed approach. A control prototype is also developed on dSPACE MicroLabBox to further investigate the interaction between the controller and the rest of the system in a more realistic testing environment.

In the present work, rice straw was carbonized using a carbonization drum. However, carbonized rice straw has poor briquetting characteristics and requires a binder. Therefore, carbonized rice straw was mixed with three types of binders at three distinct levels and densified.

The physical properties, such as density value, ranged from 0.382 to 0.518 g/cm³, and Shatter resistance ranged from 67.566% to 91.621%. The water resistance test results ranged from 54.893% to 67.894%. The value range for high heating value is 24.049 MJ/kg to 28.639 MJ/Kg, and fixed carbon content is 20.36% to 37.07%.

The TGA curve showed the sample made using starch binder at a 20% level showed the best thermal stability. However, parameters such as the high cost of starch, its extraction, and being part of the human food chain make it comparatively unsuitable for commercial use, and taro can be an alternative binder. The emission test showed that the straw briquette showed lower emissions than the CO, NO_x, and SO_x emitted from burning chopped rice straws. The specific energy consumption was highest for paper binder briquettes, followed by taro binder and starch. The water boiling test showed that as the binder level increases, the burning increases.

The emphasis and focus on energy transition towards a renewable energy-based energy system has increased, alongside the need to understand the economic feasibility of energy system development built around adaptation and implementation of renewable energy resources and smart technologies to a pre-existing energy system. Likewise comes the importance of evaluating and understanding the positive social and environmental impact obtained through energy transition towards a greener and cleaner energy system. This paper applies the cost-benefit analysis method to assess the economic feasibility of implementing renewable energy resources and smart energy technologies in a pre-existing energy system in two pilot sites (St-Jean, France and Barcelona, Spain). The evaluation process encompasses all relevant parameters such as investment, operating and maintenance costs, energy prices, energy demand, energy supply and energy technologies characteristics needed to carry out an economic feasibility assessment of investments and implementation projects. In addition, the evaluation process allows assessing the environmental benefits obtained through implementation by calculating the estimated emission reduction achieved through energy system retrofitting and transition, alongside identifying the society's economic gains attained from the emission reduction. The results show that investing in energy transition and system development toward renewable energy-based energy systems is economically viable since the analysis highlights a considerable low payback period with 8.2 years for the Barcelona pilot, and 2.8 years for St. Jean pilot. Likewise provides significant economic benefits to energy system operators and stakeholders, which is demonstrated with a 22% increase in revenue in the case of the St. Jean pilot and 4% decrease in overall costs at the Barcelona Pilot. The results highlight that energy transition offers various other benefits, such as increasing energy system flexibility with the St Jean pilot experiencing a 21% average increase in energy flexibility in the system through implementation of the energy system development. Also, this includes other benefits such as emission reduction of 23.5% for St. Jean pilot and 4% for the Barcelona pilot, which can help improve public health.

In mining, the system of operation relies on equipment that consumes large amounts of energy. In mine operations, diesel-powered equipment is widely used due to its flexibility, loading capacity, and adaptability to various terrain conditions. However, it presents high diesel oil consumption and high emission rate of greenhouse gasses, mainly carbon monoxide. This paper offers a comprehensive view of the hydrogen effect on diesel engines in the search for renewable energy alternatives that are in tune with the reduction of the environmental impact arising from the use of petroleum-derived fuels. This article presents the energy consumption of diesel-powered trucks in the mining industry. It is followed by a discussion of diesel fuel consumption and exhaust emissions. It adds to the discussion of the technologies for producing hydrogen, the advantages of using them in controlled quantities, and the challenges in production, storage as well as the supply costs. Highlight the carbon-free “green hydrogen”, which presents itself as a promising alternative in its operations to decarbonize the mines, as open pit or underground.

Residential air-conditioning units are essential for providing suitable interior comfort in regions experiencing hot climates. Nonetheless, these units contribute significantly to CO₂ emissions in these countries due to their reliance on non-renewable energy sources and the use of environmentally unfriendly working fluids. This research aims to evaluate the feasibility of operating an off-grid solar-powered air-conditioning bed unit using low-GWP refrigerants that can efficiently replace conventional refrigerants. A model was developed to evaluate the vapour compression cycle's energetic and exergetic performance. Various refrigerants were employed as feeds to the mathematical model in order to simulate the unit's performance if environmentally friendly refrigerants supersede the conventional substances. An assembled prototype air-conditioning unit was built to provide cold air to a connected canopy. Two 400 W photovoltaic panels power this system, with battery storage providing electricity to the unit at night. TRNSYS was used to evaluate the batteries' energy storage capability, whilst Integrated Environmental Solutions Virtual Environment (IESVE) was used to estimate the amount of solar energy required to power the unit. On the basis of the energetic and exergetic findings, R290 and R600a have demonstrated their suitability as replacements for conventional refrigerants. In comparison to R134a, the system showed a 2.42% improvement in COP when using R290. This improvement was accompanied by a reduction in input work by 2.31% and an increase in exergetic efficiency by 2.37%. This paper provides a guideline for analytical design, combined with a coherent process system. This offers an excellent solution to the very real problems of major energy consumption in warm countries, combining a renewable energy source with an eco-friendly air-conditioning cycle.

Battery Swapping Stations (BSS) can prove to be an integral part of the electric vehicle charging infrastructure and provide an alternative solution to the issue of range anxiety and long queuing times to charge the battery. Along with this, the increase in renewable integration in the grid as well as an increase in the number of discarded electric vehicle batteries offer another opportunity for infrastructure design while considering demand response services. In this paper, techno-economic feasibility of BSS considering the impact on electricity prices due to increased solar photovoltaics integration is analysed. An operational algorithm considering time of use tariff and estimated battery demand is designed to schedule battery charging in the battery swapping station with the objective of minimising the total charging cost. Four scenarios considering uncontrolled charging, smart charging, batteries discharging to the grid and second life batteries are designed and analysed. The results indicate that the charging cost reduces at least by 24% with smart charging and by 30% with battery to grid services. It is observed that the total charging cost can reduce further up to 19% while considering second life of batteries for storage. The study indicates the potential of novel business models in electrification of transportation, which can lead to increased opportunity for transition to sustainable transportation for developing nations.

Rooftop photovoltaic energy systems are globally recognized as crucial elements for the implementation of renewable energy in buildings, as they act as generators within the framework of smart cities. Photovoltaic modules can be designed as building roofs, and power generation units can be applied to buildings to meet the requirements of various building components. Their incorporation into building roofs remains hampered by the inherent optical and thermal properties of commercial solar cells, as well as by esthetic, economic, and social constraints. This study reviews research publications on rooftop photovoltaic systems from building to city scale. Studies on power generation potential and overall carbon emission reduction of rooftop photovoltaic systems are summarized at the macro level. The installation angle, tracking system, mechanical properties, shielding effects, indoor effects, and the life cycle of photovoltaic modules were sorted at the micro level, including their development process, advantages and disadvantages. In terms of battery materials, cadmium telluride batteries stand out among new materials with a short payback period of less than one year and a carbon dioxide emission of as little as 19 g CO₂ eq/kWh. Besides, the differences between building-integrated photovoltaic and building-applied photovoltaic are described in light of recent studies. Moreover, the application of photovoltaic rooftops, which is crucial to achieve the carbon emission peak, is also discussed. It can be found that the use of crystal silicon cells in public buildings is still the main approach of rooftop photovoltaic projects, and the maximum installed capacity of single building has exceeded 10,000 kWp. Finally, on the basis of summarizing the previous achievements, the future research focus and directions are predicted.