Publications

The production and application of hydrogen an environmentally friendly energy source have been attracting increasing interest of late. Although steam methane reforming (SMR) method is used to produce hydrogen it is difficult to build a high-fidelity model because the existing equation-oriented theoretical model cannot be used to clearly understand the heat-transfer phenomenon of a complicated reforming reactor. Herein we developed an artificial neural network (ANN)-based data-driven model using 485710 actual operation datasets for optimizing the SMR process. Data preprocessing including outlier removal and noise filtering was performed to improve the data quality. A model with high accuracy (average R2 = 0.9987) was developed which can predict six variables through hyperparameter tuning of a neural network model as follows: syngas flow rate; CO CO2 CH4 and H2 compositions; and steam temperature. During optimization the search spaces for nine operating variables namely the natural gas flow rate for the feed and fuel hydrogen flow rate for desulfurization water flow rate and temperature air flow rate SMR inlet temperature and pressure and low-temperature shift (LTS) inlet temperature were defined and applied to the developed model for predicting the thermal efficiencies for 387420489 cases. Subsequently five constraints were established to consider the feasibility of the process and the decision variables with the highest process thermal efficiency were determined. The process operating conditions showed a thermal efficiency of 85.6%.

The use of hydrogen as energy carrier in a low emission microturbine could be an interesting option for renewable energy storage distributed generation and combined heat & power. However the hydrogen using in gas turbine is limited by the NOx emissions and the difficulty to operate safely. CFD simulations represent a powerful and mature tool to perform detailed 3-D investigation for the development of a prototype before carrying out an experimental analysis. This paper describes the CFD supported redesign of the Turbec T100 microturbine combustion chamber natural gas-fired to allow the operation on 100% hydrogen.

Hydrogen-microvoid interactions were studied via unit cell analyses with different hydrogen concentrations. The absolute failure strain decreases with hydrogen concentration but the failure loci were found to follow the same trend dependent only on stress triaxiality in other words the effects of geometric constraint and hydrogen on failure are decoupled. Guided by the decoupling principle a hydrogen informed Gurson model is proposed. This model is the first practical hydrogen embrittlement simulation tool based on the hydrogen enhanced localized plasticity (HELP) mechanism. It introduces only one additional hydrogen related parameter into the Gurson model and is able to capture hydrogen enhanced internal necking failure of microvoids with accuracy; its parameter calibration procedure is straightforward and cost efficient for engineering purpose

In the context of the great research pulse on clean energy transition distributed energy systems have a key role especially in the case of integration of both renewable and traditional energy sources. The stable interest in small-scale gas turbines can further increase owing to their flexibility in both operation and fuel supply. Since their not-excellent electrical efficiency research activities on micro gas turbine (MGT) are focused on the performance improvements that are achievable in several ways like modifying the Brayton cycle integrating two or more plants using cleaner fuels. Hence during the last decades the growing interest in MGT-based energy systems encouraged the development of many numerical approaches aimed to provide a reliable and effective prediction of the energy systems’ behavior. Indeed numerical modeling can help to individuate potentialities and issues of each enhanced layout or hybrid energy system and this review aims to discuss the various layout solutions proposed by researchers with particular attention to recent publications highlighting the adopted modeling approaches and methods.

As one kind of clean zero carbon and sustainable energy hydrogen energy has been regarded as the most potential secondary energy. Recently hydrogen refueling station gradually becomes one of important distribution infrastructures that provides hydrogen sources for transport vehicles and other distribution devices. However the highly combustible nature of hydrogen may bring great hazards to environment and human. The safety design of hydrogen usage has been brought to public too. This paper is mainly focused on the hydrogen leakage and dispersion process. A new solver for gaseous buoyancy dispersion process is developed based on OpenFOAM [1]. Thermodynamic and transport properties of gases are updated by library Mutation ++ [2]. For validation two tests of hydrogen dispersion in partially opened space and closed space are presented. Numerical simulation of hydrogen dispersion behavior in hydrogen refueling station is carried out in this paper as well. From the results three phases of injection dispersion and buoyancy can be seen clearly. The profile of hydrogen concentration is tend to be Gaussian in dispersion region. Subsonic H2 jet in stagnant environment is calculated for refueling station the relationship between H2 concentration decay and velocity along the jet trajectory is obtained.

The optimal sizing of stand-alone renewable H2-based microgrids requires the load demand to be reliably satisfied by means of local renewable energy supported by a hybrid battery/hydrogen storage unit while minimizing the system costs. However this task is challenging because of the high number of components that have to be installed and operated. In this work an MILP optimization framework has been developed and applied to the off-grid village of Ginostra (on the Stromboli island Italy) which is a good example of several other insular sites throughout the Mediterranean area. A year-long time horizon was considered to model the seasonal storage which is necessary for off-grid areas that wish to achieve energy independence by relying on local renewable sources. The degradation costs of batteries and H2-based devices were included in the objective function of the optimization problem i.e. the annual cost of the system. Efficiency and investment cost curves were considered for the electrolyzer and fuel cell components in order to obtain a more detailed and precise techno-economic estimation. The design optimization was also performed with the inclusion of a general demand response program (DRP) to assess its impact on the sizing results. Moreover the effectiveness of the proposed MILP-based method was tested by comparing it with a more traditional approach based on a metaheuristic algorithm for the optimal sizing complemented with ruled-based strategies for the system operation. Thanks to its longer-term storage capability hydrogen is required for the optimal system configuration in order to reach energy self-sufficiency. Finally considering the possibility of load deferral the electricity generation cost can be reduced to an extent that depends on the amount of load that is allowed to participate in the DRP scheme. This cost reduction is mainly due to the decreased capacity of the battery storage system.

The existing combustion-centered energy mix in Malaysia has shown that replacing fossil fuels with zero-carbon alternative fuels could be a better approach to achieve the reduction of the carbon footprint of the power generation industry. In this study the potential of zero-carbon alternative fuels generated from renewable sources such as green hydrogen and green ammonia was addressed in terms of the production transport storage and utilization in Malaysia’s thermal power plants. The updated developments associated to green hydrogen and green ammonia across the globe have also been reviewed to support the existing potential in Malaysia. Though green hydrogen and green ammonia are hardly commercialized in Malaysia for the time being numerous potentialities have been identified in utilizing these fuels to achieve the zero-carbon power generation market in Malaysia. The vast and strategic location of natural gas network in Malaysia has the potential to deliver green hydrogen with minimal retrofitting required. Moreover there are active participation of Malaysia’s academic institutions in the development of water electrolysis that is the core process to convert the electricity from renewables plant into hydrogen. Malaysia also has the capacity to use its abundance of depleted gas reservoirs for the storage of green hydrogen. A large number of GT plants in Malaysia would definitely have the potential to utilize hydrogen co-firing with natural gas to minimize the amount of carbon dioxide (CO2) released. The significant number of ammonia production plants in Malaysia could provide a surplus of ammonia to be used as an alternative fuel for power plants. With regard to the energy policy in Malaysia positive acceptance of the implementation of renewable energy has been shown with the introduction of various energy policies aimed at promoting the incorporation of renewables into the energy mix. However there is still inadequate support for the implementation of alternative zero-carbon fuels in Malaysia.

Hydrogen is regarded as a promising fuel in the transition to clean energy. Nevertheless as the demand for hydrogen increases some microgrids equipped with P2H (MGH) will encounter the issue of primary energy deficiency. Meanwhile some microgrids (MGs) face the difficulty of being unable to consume surplus energy locally. Hence we interconnect MGs with different energy characteristics and then establish a collaborative scheduling model of multi-microgrids (MMGs). In this model a federated demand response (FDR) program considering predictive mean voting is designed to coordinate controllable loads of electricity heat and hydrogen in different MGs. With the coordination of FDR the users’ satisfaction and comfort in each MG are kept within an acceptable range. To further adapt to an actual working condition of the microturbine (MT) in MGH a power interaction method is proposed to maintain the operating power of the MT at the optimum load level and shave peak and shorten the operating periods of MT. In the solution process the sequence operation theory is utilized to deal with the probability density of renewable energy. A series of case studies on a test system of MMG demonstrate the effectiveness of the proposed method.

Green Print -  Future Heat for Everyone draws together technical consumer and economic considerations to create a pioneering plan to transition 22 million UK homes to low carbon heat by 2050.<br/>Our Green Print underlines the scale of the challenge ahead acknowledging that a mosaic of low carbon heating solutions will be required to meet the needs of individual communities and setting out 12 key steps that can be taken now in order to get us there<br/>The Climate Change Committee (CCC) estimates an investment spend of £250bn to upgrade insulation and heating in homes as well as provide the infrastructure to deliver the energy.<br/>This is a task of unprecedented scale the equivalent of retro-fitting 67000 homes every month from now until 2050. In this Report Cadent takes the industry lead in addressing the challenge.

A district heating system is an eco-friendly power generation facility with high energy efficiency. The boiler water wall tube used in the district heating system is exposed to extremely harsh conditions and unexpected fractures often occur during operation. In this study a corrosion failure analysis of the boiler water wall tube was performed to elucidate the failure mechanisms. The study revealed that overheating by flames was the cause of the failure of the boiler water wall tube. With an increase in temperature in a localized region the microstructure not only changed from ferrite/pearlite to martensite/bainite which made it more susceptible to brittleness but it also developed tensile residual stresses in the water-facing side by generating cavities or microcracks along the grain boundaries inside the tube. High-temperature hydrogen embrittlement combined with stress corrosion cracking initiated many microcracks inside the tube and created an intergranular fracture.