Abstract

As intermittent renewable energy is receiving increasing attention, the combination of intermittent renewable energy with large-scale energy storage technology is considered as an important technological approach for the wider application of wind power and solar energy. Pumped hydro combined with compressed air energy storage system (PHCA) is one of the energy storage systems that not only integrates the advantages but also overcomes the disadvantages of compressed air energy storage (CAES) systems and pumped hydro energy storage systems to solve the problem of energy storage in China’s arid regions. Aiming at the variable working conditions of PHCA system technology, this study proposes a new constant-pressure PHCA. The most significant characteristics of this system were that the water pump and hydroturbine work under stable conditions and this improves the working efficiency of the equipment without incurring an energy loss. In addition, the constant-pressure PHCA system was subjected to energy and exergy analysis, in expectation of exploring an attractive solution for the large-scale storage of existing intermittent renewable energy.

Highlights

  • With the increasing depletion of traditional fossil energy sources, the use of renewable energy has been attracted more and more attention

  • As suggested by the working process of the constant-pressure PHCA, when the air in the storage vessel was compressed to the pre-set pressure, compressor 1 stopped working in subsequent energy storage and power generation processes provided that the high pressure vessel was sealed

  • Energy and exergy analysis were performed for the constant-pressure PHCA system

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Summary

Introduction

With the increasing depletion of traditional fossil energy sources, the use of renewable energy has been attracted more and more attention. There are two technologies suitable for energy storage in large-scale power systems, namely, pumped hydro energy storage technology and compressed air energy storage (CAES) technology [5,6]. Kim et al [20] developed an energy storage system by maintaining a constant voltage using a fixed head of water This system improved the efficiency of CAES and solved the problem of variable working conditions. When the internal pressure in the pressure vessel P is 5 MPa, the bottom height of the virtual dam h is 500 m Based on this principle, Wang et al [21] proposed a model for a pumped hydro energy storage system to fundamentally solve the aforementioned problems by using compressed air that was used to seal the pressure vessel to artificially build that virtual dam. The results provided theoretical support for the application of the system

Physical Model and Working Principles
Thermodynamic Analysis
Initial Compression Process
Water Injection Process
Constant Pressure Process
Power Generation Process
The Influences of Work Density
Energy and Exergy Analysis
Energy Analysis
Exergy Analysis
The Exergy Balancing Relationship in a Stable Flowing System
Results and Discussion
Economic Analysis
Conclusions
Full Text
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