Deciding the location of bio refinery is an important task for management in biofuel supply and demand. This work presents a single-period deterministic model for the optimal location of butanol refinery. The developed model considers a whole system approach for butyric acid supply, butanol refinery and delivery systems. The proposed model determines where and how many refineries to be constructed and components (butyric acid and butanol) to be transported for minimizing the expected total network cost and satisfying regional demand of biofuel. The real scenario of the biofuel demand by region in South Korea is applied to validate the mathematical model. The optimization results will help to determine investment strategies for butanol production.
Microalgae biomass is composed of various bio‐ compounds which can be converted to biofuels. One type of solid fuel which can be derived from microalgae is biochar through torrefaction. However, the production of torrefied microalgae biochar may include environmental impact as it consumes raw materials and energy. A life cycle assessment of the production of torrefied microalgae biochar is proposed in the study using the torrefaction severity index. The results show the electricity requirement of the torrefaction largely contributes to the environmental impact and energy consumption. While the resulting global warming potential of the production of torrefied microalgae biochar using the torrefaction severity index yielded a non‐linear relation.
Over the past two centuries, the research on working fluids drove the tremendous progress of organic Rankine cycle to convert medium- and low-temperature heat into power efficiently. With the increasingly stringent requirements on working fluids, the search for alternative working fluids is a never-ending task. In the present work, a comprehensive review of working fluids selection of ORC is presented to summary the current research results, find out the issues and guide the future developments. The research of working fluid selection is divided into three stages according to research method firstly. Then, the research progress of each stages is summarized. In addition, the research challenges and recommendations for further research of working fluids selection and even for novel thermodynamic cycle are highlighted as well. The results show that for traditional ORC, the optimal working fluid could be selected almost by key parameters such as critical temperature, acentric factor and Jacob number, etc. More importantly, the development direction of novel thermodynamic cycle is presented.
Nowadays, the fundamental idea of district heating (DH) is to utilize local heat resources to satisfy local heat demands, otherwise those resources would be wasted. However, the mismatch between the achievable resources and fluctuating demand is challenging. This study analyzed the possibilities to solve this problem by introducing a short-term thermal storage and a seasonal thermal storage. A water tank (WT) and a borehole thermal storage (BTS) were chosen as the thermal storages. The DH system of a Norwegian university campus was selected as the case study. A high order system model was built in Modelica language. The results showed that the mismatch might be solved. The BTS brought about 3 GWh annual heat saving, and the WT brought about 110 kW average peak load shaving. However, around 0.8 GWh/year electricity was used by heat pump to recover the stored heat in the ground.
This article aims to model the transmission architecture of a planetary power split Hybrid Electric Vehicle (HEV) to improve fuel efficiency as well as to reduce emission, conforming sustainable design. The model is developed using model based equations, retrieved from literature and Design of Experiment with response surface solution mode. Development of power management strategy for the above, utilizing associated mathematical modeling of the proposed gearset topology guided transmission architecture is disseminated in this work. Design solution for suitable gearset topology is derived by utilizing response surface method and genetic algorithm. The result shows that connection between planetary gear stages, amongst considered variables, holds highest significance and also helps to infer that most suitable configuration is to couple the engine with the second planet carrier for a two-stage power split device. The modelling-based result depicts successful implementation of two stage planetary gear train as power split device with fossil fuel consumption reduction of 49.16%, maximizing electric power utilization for greener transportation.
Driven by climate change concerns, our energy system has been under steady change. Renewable energy sources are increasingly used to decarbonize our energy system, making it also more decentralized. At the same time, information and communications technologies (ICT) are enabling smart services for consumers, offering financial benefits through demand side management (DSM) programs. This study investigates various DSM solutions for a detached house in Northern Finnish conditions in 2050. A thermal model is used to model the thermal behavior of the building and test out DSM programs in direct electric space heating and underfloor heating alternatives. The 2050 scenarios are created from climate change projections, existing data on electricity generation and from projections on the future energy system and cost of electricity. The results indicate that load shifting with photovoltaic (PV) generation is a potential way of reducing costs and CO2 emissions both today and in 2050, but it lacks economic feasibility due to long payback times of the investments. Cost optimized direct electric space heating and underfloor heating are both able to provide economic and environmental benefits when compared to manually controlled heating. The scenarios presented in the paper suggest that 95-96% emission reduction can be achieved; however, the electricity cost of households is expected to increase by 174-253%. At the same time electricity consumption from the grid is expected to reduce by 3- 10% in all the scenarios.
Large scale utilization of solar energy has become an inevitable trend of an energy-efficient and environment-friendly society. A two-stage robust allocation model of solar energy equipments in district integrated energy systems is proposed in this paper with the uncertainty of solar irradiance and operating constraints of energy networks. To improve the solvability, the above non-convex non-linear model is converted to a 0-1 mixed integer second-order cone problem. The validity of the model is verified by typical cases.
Thermal management of large-format Li-ion cells is crucial due to their spatial- and temperature-dependent electrochemical reaction kinetics and heat generation. However, existing battery modeling mostly employs a pseudo-2D model which is not able to capture the local current density and temperature across the entire cell geometry. Therefore, in this paper, we propose a simplified 3D electrochemical/thermal model to investigate the temperature and voltage responses of a Li-ion pouch cell. Concurrently, a lock-in thermography experiment is conducted. The model can achieve good accuracy in predicting the surface temperature and cell voltage of the battery during cycling. A scaling analysis is subsequently carried out to determine the dimensionless numbers that affect the battery performance. The proposed approach helps to facilitate a fundamental understanding of the dominant mechanisms related to voltage polarization, heat generation and temperature non-uniformity.
The prospect of using biomass alone is broad, but there are a number of problems that make it difficult to achieve real profitability. In this paper, the thermal effects and reaction kinetics of cellulose and low-rank coal mixing at different mixing rates (25 wt%, 50 wt.% and 75 wt.%) and different heating rates (10 oC•min-1 , 20 oC•min-1 , 40 oC•min-1 ) were studied via thermogravimetric analyzer(TGA). The addition of low-rank coal can promote the formation of volatile substances in the copyrolysis process, and the degree of synergy is closely related to the heating rate and blending ratio. The kinetic results show that the average activation is 244.44 kJ•mol1 and 164.41 kJ•mol-1 when the low-rank coal blending ratio is 25% and 50%.
This paper describes the study and research taken under Project oBEMS (Office Building Energy Management System). This is an intelligent hardware and software overlay for office building automation systems based on the advance methods for measuring thermal room conditions. This method allows for managing thermal comfort in certain space by controlling installed Heating, Ventilation and Air Condition system (HVAC) in real time with the use of multisensory map of comfort.