Abstract

To improve the performance of power batteries at low temperature and reduce the dependence on the offline measurement equipment in obtaining the battery resistance, a novel thermoelectric coupling model has been employed for accurately calculating the resistance of the battery at different currents and temperatures. The Butler-Volmer(BV) equation has been proposed to describe the electrochemical reaction process of the battery. Compared with the traditional method, theoretical results show that the proposed model can accurately calculate the battery resistance and maintain the maximum calculation error less than 2mΩ. The proposed method has the potential to calculate the impedance timely and accurately.

Abstract

To address the difficulty and drawbacks of low-quality biomass such as municipal solid waste (MSW) combustion in grate boilers, co-combustion is proposed. In order to investigate how the distinction in the physical and chemical property of the fuels influences the combustion characteristics, a fuel bed model is developed with separate consideration for each fuel constituents. In this model, the kinetic parameters of chemical reactions are determined independently from single fuel combustion and applied in co-combustion simulations. It is found that the participating fuels demonstrate differences in their consumption rate and reaction peak during co-combustion. Moreover, the combustion can be improved obviously by blending in 30% of higher rank fuel.

Abstract

Energy efficiency is at the core of multiple national climate protection plans. Consequently, roadmaps for energy efficiency measures aim to undercut certain energy consumption limits for residential one- and twofamily households. However, these roadmaps are often based only on physical building parameters, neglecting the impact of occupant behavior. In this paper, we apply vine copula quantile regression to derive residential household specific conclusions on optimal long-term energetic retrofitting roadmaps under consideration of energy-economical behavior of the occupants. Our analysis shows that these behavioral factors highly impact the recommendation of certain energetic retrofitting roadmaps. Compared to generic approaches this leads to average savings of 8.2% and up to 32.8% in exceptional circumstances. We conclude that future policy decisions on energy efficiency measures for residential buildings should consider behavioral factors to lever their effects.

Abstract

Hydrogen plays a crucial role in the zero-carbon emission objective of the global 2050 long-term strategy. The injection into the gas grid, of the hydrogen “green” gas produced by the power to gas technology, is a potential solution to reduce CO2 emissions. This paper developed a steady-state model for quality tracking in gas networks. A gas distribution network with two principal natural gas sources and a localized hydrogen source was simulated. Results show how the hydrogen injected affects the pressure and the quality of gas delivered. The influence depends on the location of the injection node and changes during the day. It can be reduced by choosing an appropriate position of the hydrogen source.

Abstract

With the increasing penetration of renewable power generation and decreasing share of conventional frequency-sensitive generating units, demand-side response is playing an increasingly important role in balancing the real-time supply and demand of electric power systems. Industrial electric heating loads are critical demand-side resources because of their significant electric power consumption, large thermal energy storage capability and high automation level. In this paper, an optimal tendering method was proposed to decide the baseline load and response capacity of a group of bitumen tanks to provide the Firm Frequency Response service in the context of Great Britain. Simulation studies were conducted based on field test data of bitumen tanks and practical market data of Great Britain. The results show that the proposed method is able to minimize the net cost the tank group, considering both the energy cost in the electricity retail market and the remuneration from providing the frequency response service.

Abstract

The energy sector is undergoing decarbonization, decentralization, and digitalization. This paper explores the application of blockchain in this transition. Based on structured interviews with 15 experts of energy and blockchain in Germany, practical challenges and opportunities are explored from multiple perspectives: technological, economic, social, environmental, and institutional dimensions. A critical identified issue is the matching of regulatory change with technological advancements, potentially facilitated through multi-stakeholder engagement and regulatory sandboxes. At large, this paper aims to contribute with holistic insights and outlooks for blockchain in the energy sector.

Abstract

With the depletion of fossil energy, research on clean energy generation is developing rapidly. Though tidal phenomena contain a great deal of kinetic energy which can generate considerable power, few researches focus on configuration method of tidal generator in distribution network. In this paper, a bi-layer configuration method of tidal current turbine (TCT) in distribution network is proposed. The proposed method includes a TCT output simulation process which obtains the TCT output time-sequence curve based on historic data, and a bi-layer optimal configuration model which not only takes into account of the economics of both TCT and distribution network, but also considers the environment benefit. The configuration model is solved by using genetic algorithm and optimal power flow calculation. And, test results on IEEE 30-bus standard system verify the correctness and effectiveness of the proposed method.

Abstract

Practical use of Latent Heat Storage Unit (LHSU) is limited due to poor thermal conductivity of Phase Change Material (PCM). Present research is focused on acceleration of the charging process of LHSU using different arrangement of HTF tubes. Numerical analysis is reported for estimation of thermal performance of horizontal shell and tube type latent heat storage unit using multiple HTF tubes. In the present study stearic acid (melting point 55.7°C -56.6°C) is used as PCM. Results infer significant augmentation of charging rate for multiple HTF tubes. However, highest charging rate is obtained for those cases where more HTF tubes are placed below the diametric plane of horizontal LHSU.

Abstract

In a current power system, numbers of distribution networks are physically connected to a transmission network at different boundary buses. As the planning solution of one network significantly influences the decisions made by planners of other networks, the transmission and distribution networks should coordinate and cooperate with each other to design the entire power system in a secure and economic manner. Inspired by hierarchical and distributed optimization theories, this paper proposes a coordinated decisionmaking framework to determine the planning scheme and scenario based generation schedule for hybrid transmission and distribution networks (HTDNs). A stochastic bi-level hierarchy is presented to decompose the centralized optimal planning of HTDNs. The obtained subproblems for independent transmission and distribution networks are formulated and solved using an iterative solution process. The simulation results demonstrate the effectiveness of the proposed coordinated planning framework.

Abstract

In this paper, a simulation study on analyzing the impacts of building envelopes integrated with phase change materials (PCMs) on the night time cooling load reduction in a bedroom in sub‐tropics is reported. Firstly, the efficacy of incorporating PCMs into a west‐ facing external wall for night time cooling load reduction in a bedroom in subtropics was investigated in the benchmark study. Results showed that incorporating PCMs into the west‐facing external wall effectively reduced the night time cooling load and improved the thermal comfort in sleeping environments. Secondly, parametric studies were carried out to reveal important factors and underlying mechanisms that governed thermal performance of building envelopes integrated with PCMs. Results showed that proper selection of PCM with suitable phase change temperatures, shapes of enthalpy– temperature curve and the thicknesses of PCM was critical to reduce nighttime cooling load in bedrooms in subtropics.