Fuel cell behavior and energy balance on board a Hyundai Nexo

Hydrogen fuel consumption measuring methodologies of a fuel cell vehicle without modifying the fuel path has been tested and benchmarked. In this work, they are applied to a Hyundai Nexo fuel cell electric vehicle driving different mission profiles on a chassis dynamometer. Three methods respectively based on hydrogen tank pressure, tailpipe oxygen concentration, and IR-shared (infrared) tank data are compared to the reference method relying on fuel cell current measurements. In addition to the hydrogen fuel consumption results, the installed electrical measuring equipment made possible to yield the fuel cell efficiency map at both stack and system levels as well as the energy consumption of its balance-of-plant (BoP) components during steady-state operation. A maximum steady-state efficiency of 66.8% is reported along with a rated system power of 82 kWe involving a 9.1-kWe power consumption for the electric compressor. It is shown that the compressor and the 12-V accessories are the most energy consuming devices among the BoP components accounting for 2%–3% of the total electric energy generated by the fuel cell. Furthermore, the behavior of the powertrain system is monitored and discussed during warm-up phases and during a long idling period. Finally, based on non-intrusive temperature measurements, a short analysis is conducted about the temperature impact on the fuel cell efficiency.

EFFECT OF COMPRESSOR CARGO SUCTION PRESSURE AND TANK PRESSURE ON THE LENGTH OF THE RELIQUEFACTION PROCESS ON LPG/C GRIYA BORNEO

LPG / C Griya Borneo is a gas vessel with a semi-pressurized type, where the supporting components in the form of cargo handling equipment have a very big influence on the success and safety of ship operations. This is important to note because when the ship will carry out the loading process, the load temperature must be in accordance with the boiling point. High temperatures on ammonia loads can increase the pressure in the tank so that it exceeds the specified pressure limits and ammonia loads that have high temperatures need to be reliquefaction. In addition, the compressor compressor suction pressure that does not work in accordance with what is expected to affect the reliability process. This resulted in the reliquefaction process being longer than usual. The long reliquefaction process results in more fuel being used so that it costs a lot. Therefore the writer makes a thesis related to the problems experienced by the ship owned by PT Humpuss Transportasi Kimia aims to find out how much influence the compressor compressor suction pressure and tank pressure on the process of reliquefaction on the LPG / C Griya Borneo ship, the place where the authors practice.

Investigation of the optimum conditions for adsorptive hydrogen storage

Cryogenic adsorption using microporous materials is one of the emerging technologies for hydrogen storage in fuel cell vehicles. Metal–organic frameworks have been identified as suitable adsorbents exhibiting large hydrogen sorption at 77 K. With respect to technical realization, in this work, the deliverable capacity at the optimal storage temperature was determined for a series of MOFs in comparison to zeolite Ca-A. The deliverable capacity is defined as the amount of hydrogen released between a maximum tank pressure and a minimum back pressure and shows a maximum which defines the optimum operating temperature. This optimum operating temperature depends on the pore size of the adsorbent and the chemical properties of the surface. A number of materials are identified that exhibit optimal operating temperatures well above 100 K. A higher optimal storage temperature, however, typically results in a lower deliverable capacity.

Design of fuel system to meet China 6 emissions requirements in hybrid electric vehicle

Based on the interpretation of GB 18352.6-2016 and combined with the author's actual development experience, the key design points and solutions of the three key problems of fuel system that meet China 6 emission regulations are described, Technical route selection of evaporative emission, definition of technical route of fuel tank and control strategy of tank pressure, evaporative emission control, etc..

Techno-Economic Study on Implementation of Inventory Control Requirements for a Nuclear Powered Closed-Cycle Gas Turbine Power Plant

The use of an inventory control system offers a unique benefit of stable cycle thermal efficiency during part-load operation. This article focuses on the influence of initial inventory tank pressure on the control level using pressure differential as a driving force of the inventory control system. The study also considered the effects of using multiple tanks to increase the overall size of the inventory control tank and the use of insulation to reduce the impact of temperature variation between the compressor discharge temperature and the inventory tank temperature. The second part of this analysis is a cost comparison between the use of multiple tanks and the use of a transfer compressor to achieve high cycle efficiency at continuous part-load operation. The discussions in this paper accentuate the optimum benefit for utilizing an inventory control system for a single-shaft intercooled-recuperated closed-cycle gas turbine plant.

Computational Fluid Dynamics Thermal Analysis of ITER Pressure Suppression Tanks

The aim of the paper is to present the results of the investigation of the thermal conditions (temperature distribution, heat losses) in the support system of the vapor suppression tank (VST) of the vacuum vessel pressure suppression system (VVPSS), a safety important system of ITER fusion reactor, protecting the vacuum vessel (VV) against overpressures. The VVPSS includes four VSTs of identical volume and installed as two stacked assemblies. The study focuses on the optimization of the design of the thermal insulation at the bottom of the VSTs, interfacing with the basement and also on the identification of the thermal loads at the interface between the tank support and the tank pressure boundary. A computational fluid dynamics (CFD) analysis of the VST has been performed for four different insulation configurations and considering both steady-state and transient loads following accidental conditions. The results of the analysis are used to provide recommendation on the optimum configuration of the thermal insulation. Measures for minimization of the thermal gradient in the critical area of the joint between the tank hemispherical head and support skirt to limit the thermal fatigue on the welds are also suggested.

The Influence of Connecting Pipe on Surge Water Level and Water Hammer Pressure in Surge Tank

In the calculation of the traditional large fluctuation transition process, the influence of the connecting pipe at the bottom of the surge tank is often considered as the impedance hole. When the connecting pipe is long, the elasticity of the connecting pipe is neglected, which is liable to cause a large error. The surge joint have been mathematically modelized in two ways: with and without its connection to the pipe. Then these models have been used with the Gardel’s formula to treat the impulse coefficient of the surge tank. This study have been combined with concrete examples in order to figure out the influence of the connecting pipe’s diameter and length on the surge tank pressure, inlet pressure and unit speed of the surge tank. If the length of the linking pipe is too long, it would be necessary to consider its role. If the area of the linking pipe is too small, the surge tank will not be able to operate properly, causing water hammer waves.