Abstract

A strong demand on simultaneous increases in energy and power densities, as well as a prolonged lifetime, and increased safety of batteries at low battery costs, calls for virtual prototyping with predictive models in the early development phase. To present significant progress in the area of advanced continuum Li-ion battery models this paper presents: a) an innovative continuum modelling framework that more consistently reproduces real multi-particle size distributions and electrode topology, b) the application of thermodynamically based potential as a function of active particle lithiation in the model of the entire cell, c) consistent integration of performance and degradation models of SEI formation.
The capabilities of the modelling framework were validated on LiFePO4. The presented results clearly indicate that the proposed modelling framework features more adequate modelling representation at the level of continuum battery models. This is confirmed by the high relevance of modelled voltage vs. capacity results for low and high discharge rates and the simultaneous high relevance of interparticle transport phenomena, which are in agreement with recent nanoscopic findings. Furthermore, the presented results also confirm that the proposed modelling framework is capable of simulating degradation phenomena and thus enables adequate virtual representation of battery parameters of degraded batteries. These innovative functionalities allow – compared to the current state of the art – for a more efficient and systematic model supported design of battery based energy systems.

Abstract

Clathrate hydrate has various applications, for example, cold storage, gas transportation, CO2 capture and storage, sea water desalination, etc. Hydrate could even be applied to separate zeotropic mixtures, and the separation processes are accompanied with heat absorbing and releasing. Thus, the hydrate separation method is proposed be used in the component adjustable Organic Rankine cycle, replacing the conventional separator. In this paper, we presented a novel combined power and refrigeration cycle based on zeotropic mixtures hydrate. For the separation work could be utilized in the form of heat and there are better matching of working fluids and thermal processes, the novel cycle could meet the combined cooling and power supply, and the cycle efficiency is improved.

Abstract

Exploiting solar energy in Algeria became the main debate in energy sector especially after the oil crisis in the last three years. In fact, Algeria holds one of the best solar potential in the world, with the most efficient regions being located in the south of the country. Recently many researches have been exploiting solar energy for electricity production. However, producing hydrogen from solar energy is considered the future plan for improving the energy sector in Algeria. The main goal of this paper is the evaluation of hydrogen production potential from steam methane reforming through thermal solar energy systems in Algeria. The proposed model is based on a parabolic trough solar collector system and consists of two different parts, thermal solar energy in one hand, and hydrogen production from steam methane reforming in the other hand. The Algerian hydrogen potential production has been calculated in all regions (48 cities) of the country. The obtained results show that seasonal and the annual, hydrogen production potential could be the best solution to cover the energy needs.

Abstract

Arid pastures in northern China are scattered and large in area. Most pastures have no conventional energy power to provide stable living and production water for residents. In this paper, the typical pasture in northern China is taken as the research object. Relying on the abundant renewable energy resources and good complementarity of wind and solar energy resources, the technology of wind-solar complementary water supply for pasture is studied. In order to verify the applicability of wind-solar complementary water supply technology, water supply experiments were carried out in summer and winter in Siziwang Banner Pasture. The results show that the guaranteed rate of water supply in the experimental area using wind-solar complementary water supply technology is 142%, which fully meets the design requirements, and solves the problems of water consumption for living and production of the residents in the experimental area. It fully shows that the technology of wind-solar complementary water supply is an efficient solution to the problem of water supply in arid pasture, which provides reliable technical support for water supply in pasture.

Abstract

Improving the efficiency of the internal combustion engine is important for reducing carbon dioxide emissions in the transport sector. Various types of hybrid electric vehicles have been proposed to increase the fuel economy of the internal combustion engine-based vehicle. In a series hybrid electric vehicle, the shaft of the internal combustion engine is separated from the vehicle drive shaft. This means that even if the engine rotation speed changes within a single cycle, the vehicle power transmission is not greatly influenced by the internal combustion engine drive shaft. Therefore, it is possible to improve efficiency by modulating the speed in a single cycle of the engine. To investigate the effect of speed profile modulation on SI engine net indicated efficiency, we have optimized the intracycle speed profile of the SI engine through simulation. Simulation results show that the net indicated efficiency is improved under various speed and intake manifold pressure conditions due to combustion phasing enhancement under a high intake manifold pressure and low speed condition and improvement of heat loss and pumping work in a low intake manifold pressure condition.

Abstract

Transpired solar air collector can be used in combination with heat Pump to meet space heating and hot water demand in domestic dwellings. Moreover, the solar pre-heated fresh air can be used as a heat source for the heat pump evaporator, improving its coefficient of performance. Many research articles have been published on this subject, however the optimal analyses about techno-economic feasibility of a heat pump with the transpired solar collector are still lacking. Therefore, an optimisation tool is developed, based on non-linear programming using coherent operation strategy and variation in collector flow rate for a solar heat pump system. The effect of optimisation along with technoeconomic feasibility for a demo case in Sweden is then preliminary studied based on the defined boundary conditions. The results are used to select the most costeffective collector area installation, along with an efficient operation strategy for a given system configuration. Results indicate that the hourly flow rate optimisation can determine 35 % increased savings, compared to a non-optimised fixed flow rate case. Moreover, the simulated system has a net present value of € 5000 when calculated at 2 % discount rate for 30 years. The tool has potential use for pre-feasibility check at an earlier stage of the dedicated design and operation, without the need for extensive system simulations.

Abstract

Relative humidity (ɸ) is considered a major parameter during the designing of HVAC (Heating, ventilation, and air conditioning) systems. Generally, HVAC engineers use a psychrometric chart to observe and estimate the air quality parameters. Nevertheless, high skills are required to make rigorous and accurate reading from the psychrometric chart and the “human error” is an added factor that can lead to big disasters. Therefore, rigorous and user-friendly estimation of air quality parameters is still an ongoing issue. In this context, we are going to implement the state-of-the-art “Machine learning” technique to develop a simple, robust, and rigorous predictive tool for the estimation of relative humidity. A well-proven approach i.e., the random forest (RF) is employed to train the model for robust estimation. It was found that the mean absolute deviation was 54.3% lower than that of well-known ordinary least square (OLS) regression method.

Abstract

In this paper, a new optimization framework is developed for optimal planning of low‐carbon microgrids for clean city applications. It models the effect of recent carbon policies imposed by the environmental protection agencies on the power distribution utilities especially, in urban areas. To mimic the various techno‐ economic and social aspects of emerging dispatchable distributed generation technologies in the proposed framework, a new objective function is introduced. The moth search optimization technique is adopted to solve the problem aiming to determine the optimal mix of energy generation. Different scenarios are framed and investigated on a benchmark test distribution system of 33 buses. The simulation results are found to be inspiring in quantifying the optimal carbon cap/tax, whilst improving the system performance.

Abstract

In this paper, monarch butterfly optimization is introduced to solve an optimal deployment problem of renewable energy sources in distribution systems, aiming to minimize annual energy loss and node voltage deviation of the system. Solar photovoltaic and wind turbines are considered and formulated for a benchmark 33-bus distribution system. To demonstrate the effectiveness of this technique, obtained simulation results are compared with some of the wellknown optimization methods available in literature. The comparison shows that the monarch butterfly optimization has better solution searching ability for real-life engineering optimization problems. Additionally, it provides a higher energy loss reduction.

Abstract

The present study aims at investigating the development of porous structure during steam gasification of woody char and its effect on macroscopic reactivity. The experiments were conducted in a temperature range of 600–800 °C using biochar, derived from entrained flow gasification of biomass. The results show that the gasification temperature has minor effect on porous structure development. The total surface area of char as well as the specific total pore volume increase significantly until a certain conversion at all temperatures.