Publications

Numerical results are presented from two direct numerical simulations (DNS) where a moderate hydrogen leakage is modeled in a typical two-vented fuel cell configuration. The study mimics one of the experimental investigations carried out on the 1 m3 enclosure with a leak flow rate of 10.4 Nl.min−1 [1]. The injection dimensionless Richardson number is at the order of unity and thus characterizes a plume flow which becomes turbulent due to gravitational accelerations. Two large exterior regions are added to the computational domain to model correctly the exchange between the in/out flows at both vents and the outer environment. Two meshes are used in this study; a first consisting of 250 million cells while the second has 2 billion cells to ensure the fine DNS resolution at the level of Kolmogorov and Batchelor length scales. The high performance computation (HPC) platform TRUST is employed where the computational domain is distributed up to 5.104 central processing unit (CPU) cores. A detailed description of the flow structure and the hydrogen dispersion is provided where the sharp effect of the cross-flow on the plume is analyzed. Comparisons versus the experimental measurements show a very good agreement where both the bi-layer Linden regime and the maximal concentration in the top homogeneous layer are correctly reproduced by the DNS. This result is extremely important and breaks the limitations shown previously with statistical RANS approaches and LES models. This study can be considered as a good candidate for any further improvements of the theoretical industrial plume models in general and for the estimation of the non-constant entrainment coefficient in particular.

To achieve the UK’s net zero target vehicles including heavy-duty vehicles (HDVs) will need to be entirely decarbonised. The UK government has announced that it plans to phase out the sale of all new cars and vans with engines between 2030 and 2035. It has also announced its intention to consult on a similar phase-out for diesel-powered heavy-goods vehicles (HGVs). This study analyses policies and technologies which can contribute to the decarbonisation of the UK's inland freight sector.



It comprises an emissions modelling exercise and a cost analysis for total cost of ownership (TCO) of long-haul trucks. The study shows that for urban and regional deliveries battery electric trucks offer the best option to decarbonise. It also shows that battery electric trucks and those using an overhead catenary infrastructure are likely to be the most cost-effective pathway to decarbonise long-haul trucks by 2050 but that renewable hydrogen could also be an option.



​Link to Document Download on Transport & Environment website​​​

About 25 years ago Bogdanovic and Schwickardi (B. Bogdanovic M. Schwickardi: J. Alloys Compd. 1–9 253 (1997) discovered the catalyzed release of hydrogen from NaAlH4 . This discovery stimulated a vast research effort on light hydrides as hydrogen storage materials in particular boron hydrogen compounds. Mg(BH4 )2 with a hydrogen content of 14.9 wt % has been extensively studied and recent results shed new light on intermediate species formed during dehydrogenation. The chemistry of B3H8 − which is an important intermediate between BH4 − and B12H12 2− is presented in detail. The discovery of high ionic conductivity in the high-temperature phases of LiBH4 and Na2B12H12 opened a new research direction. The high chemical and electrochemical stability of closo-hydroborates has stimulated new research for their applications in batteries. Very recently an all-solid-state 4 V Na battery prototype using a Na4 (CB11H12)2 (B12H12) solid electrolyte has been demonstrated. In this review we present the current knowledge of possible reaction pathways involved in the successive hydrogen release reactions from BH4 − to B12H12 2− and a discussion of relevant necessary properties for high-ionic-conduction materials.

The continuous rise of global carbon emissions demands the utilization of fossil fuels in a sustainable way. Owing to various forms of emissions our environment conditions might be affected necessitating more focus of scientists and researchers to upgrade oil processing to more efficient manner. Gasification is a potential technology that can convert fossil fuels to produce clean and environmentally friendly hydrogen fuel in an economical manner. Therefore this study analyzed and examined it critically. In this study two different routes for the production of high-purity hydrogen from vacuum residue while minimizing the carbon emissions were proposed. The first route (Case I) studied the gasification of heavy vacuum residue (VR) in series with dry methane reforming (DMR). The second route studied the gasification of VR in parallel integration with DMR (Case II). After investigating both processes a brief comparison was made between the two routes of hydrogen production in terms of their CO2 emissions energy efficiency energy consumption and environmental and economic impacts. In this study the two vacuum-residue-to-hydrogen (VRTH) processes were simulated using Aspen Plus for a hydrogen production capacity of 50 t/h with 99.9 wt.% purity. The results showed that Case II offered a process energy efficiency of 57.8% which was slightly higher than that of Case I. The unit cost of the hydrogen product for Case II was USD 15.95 per metric ton of hydrogen which was almost 9% lower than that of Case I. In terms of the environmental analysis both cases had comparably low carbon emissions of around 8.3 kg of CO2/kg of hydrogen produced; with such high purity the hydrogen could be used for production of other products further downstream or for industrial applications.

To face the intensive use of natural gas and other fossil fuels to generate hydrogen water electrolysis based on renewable energy sources (RES) seems to be a viable solution. Due to their fast response times and high efficiency proton exchange membrane electrolyzer (PEM EL) is the most suitable technology for long-term energy storage combined with RES. Like fuel cells the development of fit DC-DC converters is mandatory to interface the EL to the DC grid. Given that PEM EL operating voltages are quite low and to meet requirements in terms of output current ripples new emerging interleaved DC-DC converter topologies seem to be the best candidates. In this work a three-level interleaved DC-DC buck converter has been chosen to supply a PEM EL from a DC grid. Therefore the main objective of this paper is to develop a suitable control strategy of this interleaved topology connected to a PEM EL emulator. To design the control strategy investigations have been carried out on energy efficiency hydrogen flow rate and specific energy consumption. The obtained experimental results validate the performance of the converter in protecting the PEM EL during transient operations while guaranteeing correct specific energy consumption.

Thermochemical hydrogen production process is one of the candidates of industrial fossil fuel free hydrogen production. Japan Atomic Energy Agency (JAEA) has been conducting R&D of the thermochemical water splitting iodine-sulfur (IS) process since the end of 1980s. This paper presents the recent study on the IS process in JAEA. In 2005-2009 test-fabrication of components collection of design database improvement of process components for higher thermal efficiency and proposition of composition measurement method were carried out. On the basis of them the integrity test of process components is carried out in 2010-2014 to examine their integrities in severe process environments. At present a Bunsen reactor which produces acids and incidental equipments has been already manufactured using corrosion resistant materials such as glass lining steel and fluoroplastic lining steel. Flow tests to examine the functionality and integrity of the materials are planned in 2012.

With the increase of the requirement for the economy of vehicles and the strengthening of the concept of environmental protection the development of future vehicles will develop in the direction of high efficiency and cleanliness and the current power system of vehicles based on traditional fossil fuels will gradually transition to hybrid power. As an essential technological direction for new energy vehicles the development of fuel cell passenger vehicles is of great significance in reducing transportation carbon emissions stabilizing energy supply and maintaining the sustainable development of the automotive industry. To study the fuel economy of a passenger car with the proton exchange membrane fuel cell (PEMFC) during the operating phase two typical PEMFC passenger cars test vehicles A and B were compared and analyzed. The hydrogen consumption and hydrogen emission under two operating conditions namely the different steady-state power and the Chinese Vehicle Driving Conditions-Passenger Car cycle were tested. The test results show the actual hydrogen consumption rates of vehicle A and vehicle B are 9.77 g/kM and 8.28 g/kM respectively. The average hydrogen emission rates for vehicle A and vehicle B are 1.56 g/(kW·h) and 5.40 g/(kW·h) respectively. By comparing the hydrogen purge valve opening time ratio the differences between test vehicles A and B in control strategy hydrogen consumption and emission rate are analyzed. This study will provide reference data for China to study the economics of the operational phase of PEMFC vehicles.

As environmental awareness among the public gradually improves it is predicted that the trend of green consumption will make green products enter the mainstream market. Hydrogen-electric motorcycles with eco-friendly and energy-efficient characteristics have great advantages for development. However as a type of innovative product hydrogen-electric motorcycles require further examination with regard to consumer acceptance and external variables of the products. In this study consumer behavioral intention (BI) for the use of hydrogen-electric motorcycles and its influencing factors are discussed using innovation resistance as the basis and environmental concern as the adjusting variable. Consumers’ willingness-to-pay (WTP) for hydrogen-electric motorcycles is estimated using the contingent valuation method (CVM). The results found that (1) perception barriers viz. usage barrier value barrier risk barrier tradition barrier and price barrier are statistically significant whereas image barrier is not; (2) a high degree of environmental concern will reduce the consumers’ innovation resistance to the hydrogen-electric motorcycles; (3) up to 94.79% of the respondents of the designed questionnaire suggested that the promotion of hydrogen-electric motorcycles requires a subsidy of 21.9% of the total price from the government. The mean WTP of consumers for the purchase of hydrogen-electric motorcycles is 10–15% higher than that of traditional motorcycles.

In order to improve the energy efficiency of the internal combustion engine and replace fossil fuel with alternative fuels a concept of the methanol-syngas engine was proposed and the prototype was developed. Gasoline and dissociated methanol gas (GDM) were used as dual fuels and the engine performance was investigated by simulation and experiments. Dissociated methanol gas is produced by recycling the exhaust heat. The performance and combustion process was studied and compared with the gasoline engine counterpart. There is 1.9% energy efficiency improvement and 5.5% fuel consumption reduction under 2000r/min 100 N · m working condition with methanol substitution ratio of 10%. In addition the engine efficiency further improves with an increase of dissociated methanol gas substitution ratio because of the increased heating value of the fuel and effects of hydrogen. The peak pressure in the cylinder and the peak heat release rate of the GDM engine are higher than that of the original gasoline engine with a phase closer to the top dead center (TDC). Therefore blending hydrogen-rich gas in the spark-ignition engine can recycle the exhaust heat and improve the thermal efficiency of the engine.

In this study the consequences of an accidental release of hydrogen within large scale (>15000 m3) facilities were modelled. To model the hydrogen release an LES Navier–Stokes CFD solver called fireFoam was used to calculate the dispersion and mixing of hydrogen within a large scale facility. The performance of the CFD modelling technique was evaluated through a validation study using experimental results from a 1/6 scale hydrogen release from the literature and a grid sensitivity study. Using the model a parametric study was performed varying release rates and enclosure sizes and examining the concentrations that develop. The hydrogen dispersion results were then used to calculate the corresponding pressure loads from hydrogen-air deflagrations in the facility.