A new compressed air energy storage refrigeration system

Favrat

2010

Energy

166

Energy storage systems are becoming more important for load leveling, especially for widespread use of intermittent renewable energy. Compressed air energy storage (CAES) is one of the promising methods for energy storage, but large scale CAES are dependent on the suitable underground geology. Micro-CAES with man-made air vessel is a more adaptable solution for distributed future power networks. In this paper, energy and exergy analyses of the micro-CAES system are performed and to improve the efficiency of the system, some innovative ideas are introduced. The results shows that micro-CAES system could be a very effective system for distributed power networks as a combination of energy storage, generation with various heat sources, and air-cycle heating and cooling system, with a fairly good energy density and efficiency. Quasi-isothermal compression and expansion concepts result in the best exergy efficiencies.

Section: Configuration Of the Studied Systemmentioning

confidence: 99%

Energy and exergy analysis of a micro-compressed air energy storage and air cycle heating and cooling system

Favrat

2010

Energy

166

“…To simplify the thermodynamic analysis, the majority of researchers have assumed that the cavern's wall is at a constant temperature or the cavern is adiabatic . This approach is true due to the fact that the change in the cavern's wall temperature is usually small compared with the change in air temperature.…”

Section: Theorymentioning

confidence: 99%

Performance of a small‐scale compressed air storage (CAS)

Saputro

Farid

2018

Int J Energy Res

Summary The use of renewable energy, such as wind and solar, has significantly increased in the last decade. However, these renewable technologies have the limitation of being intermittent; thus, storing energy in the form of compressed air is a promising option. In compressed air energy storage (CAES), the electrical energy from the power network is transformed into a high‐pressure storage system through a compressor. Then, when the demand for electricity is high, the stored high‐pressure air is used to drive a turbine to generate electricity. The advantages of CAES are its high energy density and quality, and for being environmentally friendly process. In the existing facilities of University of Auckland, New Zealand, air cavern is not available; thus, a high‐pressure tank is used to store the compressed air, which could provide an excellent opportunity for small size applications. There is a limited literature available on the temperature and pressure profiles in a typical high‐pressure tank during charging and discharging processes. Therefore, this research investigates how temperature and pressure inside a high‐pressure tank change during charging and discharging processes. It will provide a better understanding for heat transfer in such system. Furthermore, it will provide the necessary information needed for the designing of an efficient small‐scale CAES. In this work, air is compressed to a maximum pressure of 200 bar and stored into a 2 L tank, which is fully fitted with a pressure transducer and a thermocouple suitable for high‐pressure measurements. The charging and discharging process is theoretically modeled, and the results are compared with the experimental measurements, showing a good agreement. The heat balance on the system is used to validate the steady‐state condition, while dynamic analysis is used to predict the transient change of compressed air and tank wall temperatures. The theoretical modeling is undertaken by solving the differential equations describing the transient change in temperature of both air and tank wall. The results of this study show that air temperature rises from 24°C to 60°C at 100 bar and from approximately 17°C to over 60°C at 200 bar. During discharging process, air temperature drops from ambient to 5°C at starting pressure of 100 bar and to −20°C at starting pressure of 200 bar.

“…Transportable CAES was proposed as a solution to provide power and energy for desalination of brackish water or seawater for an island by utilizing the superchilled air as a by-product for the freeze-crystallizing process [30]. A new CAES refrigeration system was proposed for electrical power load shifting-one that employs a combination of an air cycle refrigeration cycle and a vapor compression cycle, in which the cooling effect of expanding air is used and the expansion power is used to drive a compressor of the vapor compression cycle [31]. This paper focuses on a micro-CAES system for energy storage and air cycle heating and cooling for HVAC of a building.…”

Section: Trigeneration Micro-caes Systemmentioning

confidence: 99%

Potential and Evolution of Compressed Air Energy Storage: Energy and Exergy Analyses

Lee

et al. 2012

Entropy

145

Abstract:Energy storage systems are increasingly gaining importance with regard to their role in achieving load levelling, especially for matching intermittent sources of renewable energy with customer demand, as well as for storing excess nuclear or thermal power during the daily cycle. Compressed air energy storage (CAES), with its high reliability, economic feasibility, and low environmental impact, is a promising method for large-scale energy storage. Although there are only two large-scale CAES plants in existence, recently, a number of CAES projects have been initiated around the world, and some innovative concepts of CAES have been proposed. Existing CAES plants have some disadvantages such as energy loss due to dissipation of heat of compression, use of fossil fuels, and dependence on geological formations. This paper reviews the main drawbacks of the existing CAES systems and presents some innovative concepts of CAES, such as adiabatic CAES, isothermal CAES, micro-CAES combined with air-cycle heating and cooling, and constant-pressure CAES combined with pumped hydro storage that can address such problems and widen the scope of CAES applications, by energy and exergy analyses. These analyses greatly help us to understand the characteristics of each CAES system and compare different CAES systems. OPEN ACCESS