Sustainable development using renewable energy technology

Østergaard, Poul Alberg; Duić, Neven; Noorollahi, Younes; Mikulčić, Hrvoje; Kalogirou, Soteris A.

doi:10.1016/j.renene.2019.08.094

Cited by 401 publications

(135 citation statements)

References 84 publications

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“…As people pay more attention to the use of renewable resources, many countries give priority to the development of hydropower, and China is no exception. In recent years, with the increase in hydropower stations, the security and stability of hydropower systems face more challenges [1][2][3][4][5][6]. A hydro-turbine governing system (HGS) is a coupling, nonlinear, and non-minimum phase system as it is an integration of a hydraulic, mechanical, and electrical system.…”

Section: Introductionmentioning

confidence: 99%

Design of a Finite-Time Terminal Sliding Mode Controller for a Nonlinear Hydro-Turbine Governing System

2020

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We focus on the finite-time control of a hydro-turbine governing system (HGS) in this paper. First, the nonlinear mathematical model of the hydro-turbine governing system is presented and is consistent with the actual project. Then, based on the finite-time stability theory and terminal sliding mode scheme, a new finite-time terminal sliding mode controller is designed for the hydro-turbine governing system and a detailed mathematical derivation is given. Only three vector controllers are required, which is less than the HGS equation dimensions and is easy to implement accordingly. Furthermore, numerical simulations for the proposed scheme and an existing sliding mode control are presented to verify the validity and advantage of improving transient performance. The approach proposed in this paper is simple and provides a reference for relevant hydropower systems.

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Section: Introductionmentioning

confidence: 99%

Design of a Finite-Time Terminal Sliding Mode Controller for a Nonlinear Hydro-Turbine Governing System

2020

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“…For the long-term application of GSHP system, the cold and heat accumulation around BHEs and the heat transfer quantity of BHEs decay year-by-year, domestic and foreign scholars have proposed some optimized methods and improved measures to regulate heat balance of the soil. Such as, solar assisted GSHP system (Østergaard and Duic 2019;Nouri and Noorollahi 2019;Biglarian and Saidi 2019), and cooling tower assisted GSHP system ( Liu and Li 2018;Gong and Xia 2018). Giti Nouri et al (Nouri and Noorollahi 2019) and Zhijian Liu et al (Liu and Li 2018) study solar assisted GSHP system and cooling tower assisted GSHP system, respectively.…”

Section: Introductionmentioning

confidence: 99%

Effect of the Pumping-injection flow rate on Heat Transfer Characteristic of Borehole Heat Exchangers for Coupling Ground-Source Heat Pump System

Ma¹,

Jiang²,

Zhang³

et al. 2020

Preprint

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A coupling ground source heat pump system (CGSHP) is established in areas where groundwater is shallow but the seepage velocity is weak, which sets up pumping and injection wells on both sides of borehole heat exchangers (BHEs). A convection-dispersion analytical model of excess temperature in aquifer that considers groundwater forced seepage and axial effects and thermal dispersion effects is proposed. A controllable forced seepage sandbox is built by equation analysis method and similarity criteria. Through indoor test and the proposed analytical model, the correctness and accuracy of the numerical simulation software FEFLOW7.1 is verified. The influence of different pumping-injection flow rate on the heat transfer characteristic of BHEs is studied by numerical simulation. The results show that the average heat efficiency coefficient of BHEs increases and the heat influence range of downstream BHEs expands with the increasing of pumping-injection flow rate. The relation curve between Pe and the increment of heat transfer rate per unit depth of BHEs (Δ`q) is distributed as Gaussian function. The pumping-injection flow rate that makes Darcy velocity reaches 0.6 × 10− 6~1.4 × 10− 6 m∙s− 1 in the aquifer is the best reference range for CGSHP system,so 400 ~ 600 m3∙d− 1 is taken as the best pumping-injection flow rate in this paper.

show abstract

Section: Introductionmentioning

confidence: 99%

Effect of the Pumping-injection flow rate on Heat Transfer Characteristic of Borehole Heat Exchangers for Coupling Ground-Source Heat Pump System

Jiang

Zhang

et al. 2020

Preprint

View full text Add to dashboard Cite

A coupling ground source heat pump system (CGSHP) is established in areas where groundwater is shallow but the seepage velocity is weak, which sets up pumping and injection wells on both sides of borehole heat exchangers (BHEs). A convection-dispersion analytical model of excess temperature in aquifer that considers groundwater forced seepage and axial effects and thermal dispersion effects is proposed. A controllable forced seepage sandbox is built by equation analysis method and similarity criteria. Through indoor test and the proposed analytical model, the correctness and accuracy of the numerical simulation software FEFLOW7.1 is verified. The influence of different pumping-injection flow rate on the heat transfer characteristic of BHEs is studied by numerical simulation. The results show that the average heat efficiency coefficient of BHEs increases and the heat influence range of downstream BHEs expands with the increasing of pumping-injection flow rate. The relation curve between Pe and the increment of heat transfer rate per unit depth of BHEs (Δ`q) is distributed as Gaussian function. The pumping-injection flow rate that makes Darcy velocity reaches 0.6×10-6~1.4×10-6 m∙s-1 in the aquifer is the best reference range for CGSHP system，so 400~600 m3∙d-1 is taken as the best pumping-injection flow rate in this paper.

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Sustainable development using renewable energy technology

Cited by 401 publications

References 84 publications

Design of a Finite-Time Terminal Sliding Mode Controller for a Nonlinear Hydro-Turbine Governing System

Design of a Finite-Time Terminal Sliding Mode Controller for a Nonlinear Hydro-Turbine Governing System

Effect of the Pumping-injection flow rate on Heat Transfer Characteristic of Borehole Heat Exchangers for Coupling Ground-Source Heat Pump System

Effect of the Pumping-injection flow rate on Heat Transfer Characteristic of Borehole Heat Exchangers for Coupling Ground-Source Heat Pump System

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