Geothermal development and power generation by circulating water and isobutane via a closed-loop horizontal well from hot dry rocks

2019 ◽  
Vol 136 ◽  
pp. 909-922 ◽  
Author(s):  
Yi Wang ◽  
Liang Zhang ◽  
Guodong Cui ◽  
Jun Kang ◽  
Shaoran Ren
Keyword(s):  
Power Generation ◽  
Horizontal Well ◽  
Closed Loop ◽  
Circulating Water ◽  
Hot Dry Rocks

Modeling of a Hydraulic Elevator Driven by an Open-Loop Control

2009 ◽  
Author(s):  
Roberto Strada ◽  
Alberto Oldani
Keyword(s):  
Power Generation ◽  
Closed Loop ◽  
Open Loop ◽  
The Other ◽  
Open Loop Control ◽  
Proportional Valve ◽  
Loop Control ◽  
Complete Knowledge ◽  
Motion Time ◽  
Loop Control System

Electro-hydraulic elevators are widely used systems, especially in low level buildings, due to their very good ratio between power generation and dynamic response. Generally, the goal of an elevator system is just to reach the floor with a precision enough to be comfortable for the passengers, without the need to follow a specific law of motion; hence an open-loop control system could be enough. Otherwise such a kind of solution reduces the number of components, bringing down the costs of production. On the other hand a complete knowledge of the mechanical system’s behaviour is required. In this work we deal with the analysis of the behaviour of a commercial hydraulic elevator driven by an open loop control that monitors the downstream pressure of the proportional valve supplying the cylinder. At the end of the paper, a closed loop solution based on the pressure measurement and on the motion time is proposed.

LQG Controller Design for Identified Wind Turbine Systems

2014 ◽  
Author(s):  
Young-Man Kim
Keyword(s):  
Power Generation ◽  
Wind Speed ◽  
Wind Turbine ◽  
Closed Loop ◽  
Controller Design ◽  
System Simulation ◽  
Full Range ◽  
Optimal Power ◽  
Wind Turbine System ◽  
Safety Reason

In this research, it is developed to design LQG controller for wind turbine systems which are identified with Predictor-Based System Identification (PBSID) technique. The PBSID technique works well under closed-loop condition, which is useful for a system requiring closed-loop operation due to safety reason. First, a wind turbine system is identified using PBSID technique in full range of wind speed. Afterwards, using the identified system matrices, 1-DOF LQG controller is designed. The controller enables power generation to track the optimal power trajectory of a system. Simulation is used to demonstrate its usefulness.

scholarly journals An Economic and Technology Analysis of a New High-Efficiency Biomass Cogeneration System: A Case Study in DC County, China

Energies ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3957
Author(s):  
Hui Huang ◽  
Xiaoli Yan ◽  
Shizhong Song ◽  
Yingying Du ◽  
Yanlei Guo
Keyword(s):  
Power Generation ◽  
Power Plants ◽  
High Efficiency ◽  
Biomass Energy ◽  
Utilization Efficiency ◽  
Water Heating ◽  
Circulating Water ◽  
Cogeneration System ◽  
Biomass Power Plants ◽  
Heating Technology

Biomass is the fourth largest energy source in the world; it is easy to store and can be converted into various kinds of renewable energies. The biomass cogeneration system is an important way to utilize biomass energy, especially in northern China. At present, there are many problems in biomass power plants in China, such as high latent heat loss of chimney and cooling towers, low power generation efficiency, and thermal efficiency. In order to solve this problem, this paper introduces low vacuum circulating water heating technology in the biomass cogeneration system, and expounds the differences between China and Western countries in biomass power plants. Based on this background, the technology is redesigned and reformed to make it more suitable for the biomass fuel varieties in the power plant location, and realize the localization of technology and the expansion of scale. The application of this improved technology in China’s biomass cogeneration project is analyzed. Based on the biomass cogeneration project in the DC County of China, the analysis confirms that the designed low vacuum circulating water heating technology is suitable for biomass power generation projects with agricultural and forestry wastes as raw materials, and its application can greatly improve the heat utilization efficiency of the whole cogeneration system. At the same time, in order to estimate the possibility of profitable investment when the key financial parameters change, the financial risk is analyzed. The results show that the probability of 90% net present value (NPV) in 15 years is between 355.28 million RMB and 623.96 million RMB, and the internal rate of return can reach 17.7%.

Three-Dimensional Turbulent Thermo-Elastohydrodynamic Analyses of Hybrid Thrust Foil Bearings Using Real Gas Model

2016 ◽  
Author(s):  
Fangcheng Xu ◽  
Daejong Kim
Keyword(s):  
Power Generation ◽  
Power Loss ◽  
Closed Loop ◽  
Load Capacity ◽  
Three Dimensional ◽  
Analysis Tool ◽  
Real Gas ◽  
Gas Bearings ◽  
Foil Bearings ◽  
Flow Turbulence

Environment-friendly power generation systems are active area of research. Among many systems, closed loop Brayton cycles using super critical CO2 (S-CO2) is attractive alternative to conventional power cycles due to very high efficiency and power density. When converting low temperature thermal energy such as waste heat to electrical power, closed loop organic Rankine cycles (ORC) using refrigerants are very popular. Large utility scale systems adopting S-CO2 or ORC cycles require traditional bearing systems with dry gas seals, but small systems with shaft power less than 1MW are best suited with gas bearings lubricated with the cycle fluids. Foil gas bearings, which have been successfully applied to the air blowers/compressors and small power generation gas turbines, are the best candidate for the small S-CO2 or ORC cycle systems. However, design/analysis tool of the foil bearings with these non-ideal gases is rare. In addition, thrust foil bearings are technically more challenging compared to radial foil bearings due to low load capacity and large power loss due to high flow turbulence. This paper presents high level analysis tool involving three-dimensional thermo-hydrodynamic analyses of hybrid thrust foil bearings employing real gas effect and flow turbulence inside the film. The pressure distribution, temperature distribution, load capacity, film thickness, and power loss of 154mm hybrid thrust foil bearings are presented.

Sign in / Sign up

Export Citation Format

Share Document