Abstract

With the recently announced 2060 carbon neutrality goal by China, high penetration of renewable resources in power sector can be expected. However, the intermittent nature of wind and solar energies requires the deployment of dispatchable technologies and also raises the problem of power curtailment. In this work, a case study on China’s power sector in 2018 is conducted as if carbon neutrality was to be enforced. Both fossil fuels and renewable resources are utilized for power supply to match hourly demand profile at minimum system cost. Moreover, the amount of power curtailment is estimated from the optimal carbon neutral power mix. Leveraging on the concept of energy-chemical nexus, the potential of producing green methanol and ammonia in China from hydrogen via water electrolysis with curtailed power is investigated.

Abstract

Calcium carbide is one of the important basic coal chemical products in China. Oxy-thermal method is a potential alternative to electro-thermal method to overcome the disadvantages of high energy consumption, high material consumption, and high pollution. However, the traditional oxy-thermal method is in the laboratory research stage due to the constraints of high carbon consumption, low utilization rate of solid waste and immature technology. Therefore, a novel system of carbon-calcium compound conversion for calcium carbide-acetylene production, which couples carbon capture and calcium carbide waste slag reuse process to achieve CO2 enrichment and calcium cycle, is proposed in this paper. Based on the simulation data, the system is comprehensively evaluated by material conversion, energy utilization, exergy analyses. It is found that the proposed coupling process has the largest effective atom yield of carbon, hydrogen, and calcium, which is 85.41%. In addition, the coupling module of this process can recycle the solid waste carbide slag and the carbon capture rate is more than 90%. It is worth noting that the unit product carbon consumption of proposed system is 2.02 t Coal· t-1 C2H2, which is only 0.37 times that of the traditional process. Moreover, although the 43.21% exergy efficiency of the proposed system with steam gasification agent is slightly lower than the 49.37% of traditional system, it was considered that the former is a relatively superior process because of its comprehensive better performance than the latter. From above, the proposed system is high-efficiency, low-carbon and clean for calcium carbide-acetylene production, which could be a promising process as innovative technology for carbon emission reduction in practical applications.

Abstract

With the necessity of new technologies to move energy systems from fossil to renewable sources, hydrogen takes an important role within the discussion. Whether in transport, industry, commerce, or private energy supply, hydrogen is predicted to be one of the main suppliers in our energy systems of the future. To enable a safe and easy solution for transportation, existing natural gas infrastructures can be used. Originally those structures were built for gas mixtures that contained higher amounts of hydrogen than the gas mixtures which are transported nowadays. But when fluctuating amounts of hydrogen are added to natural gas, it is important to determine the actual concentration of hydrogen – not only for the decreasing heating value but also the change in gas qualities and behavior of the mixture.
With advanced measurement principles and technologies, these concentrations could be determined due to their effect on thermodynamical properties. This paper summarizes the effects of hydrogen on natural gas mixtures and evaluates how these effects can be used to determine the composition of the gas. By knowing the hydrogen concentration, gas qualities can be recalculated and end devices adjusted to the changing conditions.

Abstract

Most recently, the federal government in Germany published new climate goals in order reach climate neutrality by 2045. This paper demonstrates a path to a cost optimal energy supply system for the German power grid until the year 2050. With special regard to regionality, the system is based on yearly myopic optimization with the required energy system transformation measures and the associated system costs.
The results point out, that energy storage systems (ESS) are fundamental for renewables integration in order to have a feasible energy transition. Moreover, the investment in storage technologies increased the usage of the solar and wind technologies. Solar energy investments were highly accompanied with the installation of short-term battery storage. Longer-term storage technologies, such as H2, were accompanied with high installations of wind technologies. The results pointed out that hydrogen investments are expected to overrule short-term batteries if their cost continues to decrease sharply. Moreover, with a strong presence of ESS in the energy system, biomass energy is expected to be completely ruled out from the energy mix.
With the current emission reduction strategy and without a strong presence of large scale ESS into the system, it is unlikely that the Paris agreement 2° C target by 2050 will be achieved, let alone the 1.5° C.

Abstract

The mechanism of climate is explained with the mathematical model created by Prof. Dr. Milutin Milankovic that is used to calculate and point the appearance of the Ice Ages. Changes in electromagnetic radiation that we receive, with the quantification and classification of renewable energies has been presented. To reverse climate changes, methodology and application are proposed with Direct Renewable Energy Application.

Abstract

With increased renewable energy sources such as photovoltaics and an increased need for decarbonization, investing in energy storage methods will be vital. In this paper, a thermal energy storage for sport facilities with photovoltaic overproduction was examined to investigate the economic and heat decarbonization potential. A MATLAB model for a latent heat thermal energy storage was created with hourly input data of heat demand, electric demand, and PV production. The storage uses a phase change material for converting electricity to heat from overproduction of PV and from an auxiliary heater connected to the grid to cover a heat demand. The system became most profitable with 100% auxiliary compensation from the electric grid, due to utilization of grid electricity during the colder months which has more costly heat prices. With an optimal storage size of 510 kWh, it was able to utilize 82% of the annual PV overproduction, reduce the heat demand by up to 12%, mitigate 304 tons worth of CO2 emissions, and generate a profit of 23 200 EUR. With these results, LHTES has the potential to be a feasible option for energy storage with the rise of variable renewable energy sources.

Abstract

Global warming is increasing average air temperature, affecting energy consumption and thermal comfort inside buildings. This study investigates the relative impact of climate change on thermal energy needs and indoor thermal comfort conditions for a typical residential building located in different climates of Pakistan. Furthermore, the energy-saving potential and thermal comfort performance of various traditional and advanced retrofit measures are evaluated to mitigate the impact of climate change. Climate Change World Weather File Generator was used to produce weather files of typical metrological years of 2020, 2050, and 2080 under emission scenario A2 of the Intergovernmental Panel on Climate Change (IPCC). TRNSYS simulation software and ASHRAE adaptive discomfort model were used to calculate annual thermal energy demand and comfort conditions inside the buildings. The impact of climate is city-specific. Overall, results show that the temperature will increase in the range of 0.9-1.4 °C and 2.3-3.7 °C for the year 2050 and 2080 respectively from the present level (2020) while the absolute humidity increase range is 0.2-1.3 and 0.3 to 3.3 g/kg of air for the same years in the investigated cities of Pakistan. This would result in higher thermal energy needs for cooling in the range of 9.7-28.4 kWh/m2 by 2050 and 28.4-49.9 kWh/m2 by 2080. The climate-responsive retrofit solutions should be promoted by authorities and policymakers to strengthen a climate-resilient pathway of building stock in Pakistan.

Abstract

A zero-dimensional (0D) kinetic model for biomass gasification is here presented for the estimation of the resulting syngas composition and chemical properties. It is based on the description of the surface reactions kinetics taking place in the char reduction area. This model is enriched by an appropriate kinetics for the prediction of the TAR moles in the synthesis gas and by an energy balance equation between reactant species and products to predict the gasification temperature. Although it has been first developed for fixed bed downdraft reactors, it has also been validated for fluid bed reactors after an appropriate calibration of the residence time. The model well reproduces the measured trends, with an overall error lower than 12%.

Abstract

NaCl-CaCl2 binary eutectic mixture is potential high-temperature heat storage molten salt material. It has the advantages of high working temperature upper limit and good thermal stability. However, its high temperature thermophysical properties are difficult to measure. An effective solution is to calculate and predict the thermophysical properties of molten salts through classical molecular dynamics simulation. The lack of reasonable potential parameters of positive divalent chloride molten salts restricts the accurate calculation of the properties. In this study, the appropriate potential parameters of CaCl2 were determined by comparing the calculated and experimental data of density and coordination number for molten CaCl2 or NaCl-CaCl2 eutectic mixture. The results show that the determined potential parameters of SP2 series are reasonable and can be selected to accurately calculate the thermophysical properties of calcium- containing chloride mixture molten salts.

Abstract

Engine electric accessories are a promising technical approach to improve engine fuel efficiency. The engine’s electric cooling fan, however, with few signals to controllers, has a challenging fault detection issue. In this paper, a fault diagnosis algorithm based on model and support vector machine was proposed. Firstly, a dynamic model of electric motor-cooling fan system was established, then a real time model-based observer was designed to estimate the torque of the cooling fan. The load torque estimated with control signals was used to identify cooling fan model parameters. According to the identified parameters, a support vector machine (SVM) was utilized for fault classification . The simulation and experiment showed ,this diagnosis algorithm was able to discover over 98% mechanical failures with an classification accuracy of 95%.