Future Energy

Comparative analysis of electrochemical behaviors of lithium-ion batteries using the dual potential MSMD battery models: case studies on various thermal conditions

Nirjhor Barua — 2023-07-15

The high energy density and long cycle life of lithium-ion batteries make them a preferred option for electric vehicles. The efficiency and life span of lithium-ion batteries are particularly sensitive to temperature; thus, it becomes essential to maintain an ideal temperature range. In this context, we concentrated on two widely used electro-chemistry (Equivalent Circuit Model and NTGK) models of a single cell of a dual potential MSMD Lithium-ion Battery while taking into account two significant methods of heat transfer under varying C-rates (0.25C, 1C, 2C, and 5C). We investigated the highest temperatures that two e-chemistry models could reach in varying ambient temperatures (typical summer, winter, and room temperature). The maximum temperature-raising tendency in the ECM due to natural convection is greater than the maximum temperature-raising tendency due to radiation regardless of the environmental temperatures and various C rates (0.25C, 1C, and 2C ). However, the trend line of the maximum temperature rise is different in the NTGK model, where the maximum temperature rise due to radiation is greater than the maximum temperature rise due to convection for 0.25C, 1C, and 2C rates in -5°C and 40°C environmental temperatures. In the NTGK model, at 0.25C, 1C, and 2C rates for winter and summer temperatures, the maximum temperature rise owing to radiation is larger than that due to convection. The NTGK model, however, produced somewhat superior findings for the radiation mode of heat transfer at ambient temperature. Therefore, it can be said that convection is a better thermal condition than natural convection in the NTGK model.

Development a policy for the production of Bitcoins with renewable energy sources

Mehdi Aliehyaei — 2023-07-16

Bitcoin, the first decentralized digital currency introduced by an anonymous person or group since 2008, has attracted worldwide attention. A significant number of economists have introduced Bitcoin as a new phenomenon in the 21st century that could reduce global inflation. Given the tens of thousands of digital currencies that have emerged since the advent of Bitcoin and its price growth trend over more than a decade, which are signs of the growth of this business. In addition to being money, Bitcoin has always been considered a tool for investing and storing value, which is why it is called digital gold. One of the most important problems in the production or extraction of Bitcoins is the high-power consumption by miners. If the energy sources of electricity generation are supplied by non-renewable energy sources, in addition to emitting air pollutant gases, it will increase greenhouse gases and consequently contribute to climate change. In this research, based on the idea of the authors, which is that the economic support of Bitcoin is energy, a strategy for producing Bitcoin from renewable energy sources is considered. First, the amount of electrical energy consumption by Bitcoin production is calculated based on statistical data, and then based on the price of electricity in different countries of the world and its global average, the base price of Bitcoin is calculated. In the following, four scenarios are proposed for the production of Bitcoin by electricity supplied from non-renewable energy sources. These scenarios include coal-fired steam power plants, natural gas-fired power plants, natural gas/oil gas-fired power plants, and dual-cycle (steam and gas cycles) natural gas-fired power plants. Based on the amount of electricity required to produce one Bitcoin, the amount of pollutants emitted to produce Bitcoin and its social costs are calculated. These costs should be added to the base cost of Bitcoin production if non-renewable energy sources are used to produce Bitcoin. Then, renewable energy sources for Bitcoin production based on the price of electricity generated by renewable energy sources are examined. Based on the analyses, how to choose the best renewable energy source to produce Bitcoin is presented as a scenario. This article briefly answers two key questions: 1. At what price of Bitcoin is it cost-effective for governments to produce it? 2. What is the best renewable energy source to produce it? These two questions can be useful in creating a roadmap and strategy for economists and governments.

CO2 emission from the electricity sector in Iran; calculation, prediction and reduction policies

Hossein Yousefi — 2023-08-08

Fossil fuel power plants produce a significant amount of CO₂ emissions, and this pollutant causes global warming, respiratory and heart diseases, and other significant issues. Electricity interprets as a primary and rising demand in each energy system; thus, in this paper, carbon dioxide (CO₂) emission reduction was selected as the objective value for 2025. Power plant fuel consumption was surveyed to calculate the CO₂ emission caused by each fuel. Also, Esfahan province (an industrial province in Iran) was investigated as the study case. Forecasting the fuel consumption for 2025 was run by two parameters: population and Gross Domestic Production (GDP), which were forecasted by the report of the Iran Statics Center and the Gaussian Process Regression (GPR) method, respectively. The CO₂ emission of power plants was obtained using the coefficients of each fuel. Based on Iran's commitment to the Paris Agreement, a 4% reduction of CO₂ emissions is the main objective. Thus, this study aims to reach this goal by implementing four scenarios: a) adding renewable energies, b) adding renewable energies and improving the generation efficiency, c) adding renewable energies and decreasing the grid losses, and d) combining the three scenarios mentioned above. According to these scenarios, reformation strategies compensated 10.5% of the required power, which was satisfied by renewable energies, and finally, this province can gradually satisfy a 4% reduction until 2025.

Energy consumption reduction in a building by free cooling using phase change material (PCM)

Aidin Shaghaghi — 2023-08-14

It is significantly important to implement energy storage systems nowadays. Latent heat thermal energy storage (LHTES) systems contain numerous advantages as a result of their small temperature variation and higher energy storage densities during storage. The present paper deals with the cooling load of a room in Zanjan, Iran using Carrier software. Then, a free cooling system using commercial paraffin RT25 was numerically analyzed as phase change material (PCM) while investigating the effects of the flow rate of the storage tank and inlet air temperature overcharging and discharging procedures. Based on cold energy storage simulation, by airflow with the temperature of 20°C at night, the paraffin is solidified in 4 h. Stored cold energy of 1.4 kW in PCM releases energy through a free cooling system within 2.1 h of July afternoon in the room.

Simulation model of carbon capture with MEA and the effect of temperature and duty on efficiency

Ali Majnoon — 2023-09-21

Humans continue to rely on fossil fuels to generate electricity. In other words, fossil fuels are the world's largest energy producers. Fossil fuels produce significant carbon dioxide, mostly in areas where humans live. Although the share of carbon dioxide produced in big cities is minimal compared to the carbon dioxide production of volcanoes, the production of carbon dioxide in big cities has destructive effects. Process Simulator is utilized to evaluate the effectiveness of their simulation model by subjecting it to various experimental conditions, including liquid loading, temperature, and CO₂ absorption (PPS). Comparing empirical and simulated mass transfer coefficients distinguishes this study from others. This procedure consists of two steps: Carbon dioxide (CO₂) absorption in a solvent produces highly concentrated CO₂ gas following solvent regeneration. A chemical adsorption process's scalability depends on accurate simulation models, typically validated using data from a pilot plant. With the aid of this study, a simulation model of a desorption column is constructed with ASPEN PLUS and 42% MEA validated. In addition, the effect of the weight percentage of 20-42 MEA in the inlet stream on the efficiency is investigated, and the influence of the MEA inlet temperature on system efficiency is examined. Then, the recommended temperature is confirmed based on the MEA's heat tolerance capacity of 303 Kelvin.