Jingying Li¹, Tiejun Zhu¹, Fengming Li¹, Dong Wang¹, Xianbiao Bu², Lingbao Wang^2,*

Energy Engineering, Vol.118, No.3, pp. 517-534, 2021, DOI:10.32604/EE.2021.014464

Abstract The single well geothermal heating (SWGH) technology has attracted extensive attention. To enhance heat extraction from SWGH, a mathematical model describing heat transfer is set up, and the key influence factor and heat transfer enhancement method are discussed by thermal resistance analysis. The numerical results show that the thermal resistance of rock is far greater than that of well wall and fluid. So, reducing rock thermal resistance is the most effective method for enhancing the heat extraction power. For geothermal well planning to drill: rock thermal resistance can be reduced by increasing well diameter and rock thermal conductivity; the temperature… More >

Zhongjia Li¹, Jianfeng Pan^1,*, Hongjun Liu¹, Baowei Fan¹, Wenming Yang², Abiodun Oluwaleke Ojo¹

Energy Engineering, Vol.118, No.3, pp. 581-603, 2021, DOI:10.32604/EE.2021.014378

Abstract In order to improve the performance of the rotary engine, this paper has designed a new type of dual-pit rotary engine combustion chamber structure, and compares the combustion and emission characteristics with the rotary engine with a traditional combustion chamber. The existence of the dual-pit combustion chamber strengthens the overall vortex intensity in the cylinder, effectively promotes the mixing process of fuel and air in the cylinder, the maximum combustion pressure in the cylinder increased by 8.6%, significantly increases the diffusion combustion speed, and significantly improves the dynamic performance of the rotary engine. On this basis, the effects of fuel… More >

Taihong Liu¹, Dingchen Wu^2,*, Fei Xu³, Panpan Song², Mingshan Wei², Jian Wu¹, Xiaochun Bai¹

Energy Engineering, Vol.118, No.3, pp. 535-548, 2021, DOI:10.32604/EE.2021.014326

Abstract In view of the Three North areas existing wind power absorption and environment pollution problems, the previous scholars have improved the wind abandon problem by adding electrothermal coupling equipment or optimizing power grid operation. In this paper, an electrothermal integrated energy system including heat pump and thermal storage units was proposed. The scheduling model was based on the load data and the output characteristics of power units, each power unit capacity was programmed without constraints, and the proposed scheduling model was compared with the traditional combined heat and power scheduling model. Results showed that the investment and pollutant discharge of… More >

Chunhua Jin, Hanqing Hu^*

Energy Engineering, Vol.118, No.3, pp. 655-665, 2021, DOI:10.32604/EE.2021.014281

Abstract With the increase of total energy consumption, eco-environmental quality drops sharply, which has attracted concerns from all circles. It has become the top priority of construction of socialist ecological civilization to clarify the influences of energy consumption on the level of eco-environmental pollution. Ecological environmental pollution control cannot be one size fits all. It can avoid resource depletion and environmental deterioration via adjusting measures to local conditions to coordinate ecological environmental pollution and energy consumption problems. In this essay, entropy method is adopted to measure the composite indexes of eco-environmental pollution of 30 provinces and cities in China, based on… More >

Fangqi Liu¹, Xianpeng Zeng^1,2, Yimin Xia¹, Zihao Wang¹, Dunxi Yu^1,*

Energy Engineering, Vol.118, No.3, pp. 459-471, 2021, DOI:10.32604/EE.2021.014240

Abstract The previous work found that the additive kaolin could scavenge not only sodium (Na) but also calcium (Ca) and magnesium (Mg), which is the important ash fluxing agents in low rank coal combustion. Such scavenging effects of kaolin on fine ash formation were studied in the present work. A typical Zhundong coal and its blends with kaolin at dosages of 1, 2 and 4 wt% were combusted in an electrically heated drop tube furnace (DTF) at 1300°C. The fine ashes generated were collected and size segregated by a low pressure impactor (LPI). The morphology and chemical composition of fine ash… More >

Suvash C. Saha^1,*, Ali M. Sefidan², Atta Sojoudi³, Mohammad M. Molla⁴

Energy Engineering, Vol.118, No.3, pp. 487-506, 2021, DOI:10.32604/EE.2021.014088

Abstract One primordial consideration in residential ventilation standards is the comfort of provided to people living in those habitations. This is highly dependent on the thermal and fluid flow conditions, the space geometry and so on. Efficient designs may reduce the energy usage, making the buildings more sustainable over a longer period of time. This study aims to investigate the impact of whole day thermal conditions on the fluid flow structure and heat transfer phenomena, mainly natural convection, inside a partitioned attic-shaped configuration. The Finite Volume Method is applied to solve the governing equations. Sinusoidal thermal boundary condition is applied on… More >

Yingbo Zhang¹, Shi Chen^1,2,*

Energy Engineering, Vol.118, No.3, pp. 707-714, 2021, DOI:10.32604/EE.2021.013888

Abstract In the mining process of coal mine, waterproof coal pillars should be set between the weathered oxidation zone and the first mining face. In order to determine the reasonable upper limit of the first mining face of Hongyi Coal Mine, the waterproof coal pillar needs to be wide enough to resist the lateral hydrostatic pressure of the oxidation zone, and to ensure that the top plate aquifer does not run through the water guide crack zone, while also liberating as much stagnant coal as possible. In this paper, the first coal mine face’s waterproof coal pillar was calculated using conventional… More >

P. Murugan¹, S. Dhanushkodi^2,*, K. Sudhakar^3,4,*, Vincent H. Wilson⁵

Energy Engineering, Vol.118, No.3, pp. 435-446, 2021, DOI:10.32604/EE.2021.013491

Abstract The quality of the drying process depends mainly on the efficient use of thermal energy. Sustainable systems based on solar energy takes a leading role in the drying of agro-products because of low operating cost. However, they are limited in use during off–sun periods. Biomass dryer is one of the simplest ways of drying because of its potential to dry products regardless of time and climate conditions. The other benefit is that crop residues could be used as fuel in these systems. However, the major limitation of the dryer is unequal drying because of poor airflow distribution in the drying… More >

Xian Ma¹, Tingyan Lv^2,*, Yingqiang Jin², Rongmin Chen², Dengxian Dong², Yingtao Jia²

Energy Engineering, Vol.118, No.3, pp. 691-705, 2021, DOI:10.32604/EE.2021.012701

Abstract The large number of gas turbines in large power companies is difficult to manage. A large amount of the data from the generating units is not mined and utilized for fault analysis. This study focuses on F-class (9F.05) gas turbine generators and uses unsupervised learning and cloud computing technologies to analyse the faults for the gas turbines. Remote monitoring of the operational status are conducted. The study proposes a cloud computing service architecture for large gas turbine objects, which uses unsupervised learning models to monitor the operational state of the gas turbine. Faults such as chamber seal failure, load abnormality… More >

G. Indira Kishore¹, M. Premkumar^1,*, Ramesh Kumar Tripathi², Chandra Sekhar Nalamati²

Energy Engineering, Vol.118, No.2, pp. 199-209, 2021, DOI:10.32604/EE.2021.014079

Abstract Renewable energy with sources such as photovoltaic (PV) or fuel cells can be utilized for the generation of electrical power. But these sources generate fewer voltage values and therefore require high gain converters to match with DC bus voltage in microgrids. These high gain converters can be implemented with switched capacitors to meet the required DC bus voltage. Switched capacitors operate in a series and parallel combination during switching operation and produce high static gain, limits reverse voltage that appears across the components. A novel converter is proposed that satisfies all the features such as high voltage gain, only one… More >