MaimAir: A flexible and modular energy storage system for tomorrow energy banks

We considered a novel energy storage system based on the compression of air through pumped water. Differently from CAES on trial, the proposed indirect compression leaves the opportunity to choose the kind of compression from adiabatic to isothermal. The energy storage process could be both fast or slow leading to different configuration and applications. These novel storage system are modular and could be applied in different scales for different locations and applications, being very flexible in charge and discharge process. The system may offer an ideal energy buffer for wind and solar storage with no (or negligible) environment hazard. The main features of this novel energy storage system will be showed together with overall energy and power data. Despite CAES technology has already started being exploited, a lot of improvement is possible. In traditional CAES, compression of air takes place in the compressor, that is then moved to the storage vessel. Similarly, air is taken from the vessel and introduced in turbine for expansion. In the proposed system, air is compressed and expands directly in the storage vessel. This is done through a water piston that modifies air volume, reducing it during charge and increasing it during discharge. The water piston is used as heat storage so to absorb heat during compression and reject it during expansion, too. The new system is thus a Hydraulic compressed air energy storage (HYCAES). It is composed of high pressure storage vessel, almost full of air when fully out of power, an atmospheric pond for water storage, a water pump and a hydraulic turbine and connecting pipes. It is not ever-new, as there are some papers illustrating similar systems . In present paper, thermodynamic aspects of proposed systems will be analyzed to prove its energy feasibilit

Performance assessment of Adiabatic Compressed Air Energy Storage (A-CAES) power plants integrated with packed-bed thermocline storage systems

Among energy storage technologies, compressed air energy storage (CAES) systems have undergone a real development since the 70s, although only two large-size commercial plants are operating worldwide. CAES systems allow very large energy storage to be performed, accumulating compressed air to be used for electrical energy generation. In recent years, A-CAES (Adiabatic Compressed Air Energy Storage) plants have had an important role. This technology allows the storage of the thermal energy released during air compression to be used for heating the compressed air during electricity generation, avoiding the consumption of fossil fuels. The main objective of this paper is to propose an innovative system solution for large-size A-CAES plants. The proposed configuration is characterized by: (i) a compression train based on two axial compressors constantly operating at design conditions and a centrifugal compressor fully devoted to managing the pressure variation, (ii) a thermocline thermal energy storage (TES) system based on a packed bed of solid material located between the low-pressure and high-pressure compressors, (iii) an expansion train based on a high-pressure radial turbine and a low-pressure axial turbine. TES performance was evaluated with integration with the A-CAES plant through a dedicated numerical simulation model. Operating modes for managing the high-pressure and low-pressure turbines through air throttling and high-pressure turbine bypassing were also studied. Finally, an in-depth analysis of the off-design behaviour of the different A-CAES components was carried out. Globally the A-CAES round trip efficiency exceeds 0.7â0.75

Optimisation of compressed air system’s energy usage through discrete event simulation: Compressor performance

Compressed air systems (CAS) utilised in manufacturing processes require significant energy input for operation. The estimated cost of producing compressed air is considered high with little transparency available when assessing its value in manufacturing. There is currently poor awareness of the performance of CAS in relation to its equipment utilisation and energy optimisation. This paper presents a modified approach to the Energy Blocks methodology for representation and simplification of compressed airflow profiles in discrete event simulations (DES). The presented AirBlocks methodology significantly reduces the aggregate data required to represent the dynamic and interdependent nature of CAS. Combining the AirBlocks approach with manufacturing throughout productivity simulations allows a productivity oriented compressed air demand profile to be developed. This offers the capacity to estimate periods of sustained peak, average and minimum air demand, incidents of production stoppages due to air demand, incidents of production due to air starvation and, identify waste and saving potential in the system. This paper includes an industrial case study where the AirBlocks approach was used in evaluating the performance of an existing CAS. Through simulation - poor compressor utilisation and regular incidents of air starvation were identified as symptoms of insufficient CAS volumetric capacity and an oversized compressor system in an automotive engine manufacturing plant

Transcritical Carbon Dioxide Charge-Discharge Energy Storage with Integration of Solar Energy

New and improved energy storage technologies are required to overcome non-dispatchability, which is the main challenge for the successful integration of large shares of renewable energy within energy supply systems. Energy storage is proposed to tackle daily variations on the demand side, i.e., storing low-price energy during off-peak or valley periods for utilization during peak periods. Regarding electrical energy storage, several technologies are available with different potentials for scalability, density, and cost. A recent approach for grid-scale applications is based on transcritical carbon dioxide charge and discharge cycles in combination with thermal energy storage systems. This alternative to pumped-hydro and compressed air energy storage has been discussed in scientific literature, where different configurations have been proposed and their efficiency and costs calculated. The potential of the concept has been demonstrated to be an economical alternative, including hybrid concepts with solar thermal storage. Even at low temperatures, the addition of solar energy has proved to be cost effective. This paper explores the effect of introducing solar-based high temperature heat on the performance of different configurations of “Transcritical carbon dioxide ‒ thermal energy storage system” cycles. A base-cycle with 8-hour discharge time is compared with different layouts. Discussions include details on the models, parametric analyses -including solar technology alternatives-, and simulation results. Round trip efficiency of the base case, without solar support and at pressure ratio of 9.4, is 52%. When solar input is considered, the efficiency is above 60%, increasing the turbine inlet temperature to 950 K. Estimated levelized cost of electricity values are in the range of pumped hydro and compressed air energy storage, 90-140 USD/MWh in agreement with other works on this thermal storage technology. The global analysis shows clear advantages for advancing in the study and definition of this technology for exploitation of synergies at different power ranges, integrated with mid/high temperature solar power plants and with smaller-scale renewable installations.Unión Europea. Fondo Europeo de Desarrollo Regional SOE1 / P3 / P0429E

Sandman futura

Micro air abrasion is a new modern method for removing decay and old fillings. It is used a fine stream of aluminium oxide powder and compressed air. Micro air abrasion was discovered in 1940 in USA. Sandman’s unique patented whirl system and special hand pieces secure a unique precision and working condition of the aluminium oxide powder. Dentists can obtain optimal results using the unit with a working pressure between 1½ - 3 bars. In comparison, other systems are used pressure working area of 4 - 8 bars

Feasibility study of a simulation software tool development for dynamic modelling and transient control of adiabatic compressed air energy storage with its electrical power system applications

The field of large-scale electrical energy storage is growing rapidly in both academia and industry, which has driven a fast increase in the research and development on adiabatic compressed air energy storage. The significant challenge of adiabatic compressed air energy storage with its thermal energy storage is in the complexity of the system dynamic characteristics arising from the multi-physical (pneumatic, thermal, mechanical and electrical) processes. This has led to a strong demand for simulation software tools specifically for dynamic modelling and transient control of relevant multi-scale components, subsystems and whole systems with different configurations. The paper presents a feasibility study of a simulation tool development implemented by the University of Warwick Engineering team to achieve this purpose. The developed tool includes a range of validated simulation models from the fields of pneumatics, thermodynamics, heat transfer, electrical machines and power grids. The structure of the developed tool is introduced and a component library is built up on the Matlab/Simulink platform. The mathematical descriptions of key components are presented, which precedes a presentation of four case studies of different applications. The case studies demonstrate that the simulation software tool can be used for dynamic modelling of multi-scale adiabatic compressed air energy storage components and systems, real performance analysis, dynamic control strategy implementation and feasibility studies of applications of adiabatic compressed air energy storage integrated with power grids. The paper concludes that the continued development and use of such a tool is both feasible and valuable

Vibration Analysis and Optimal Design of Pneumatic Circuits Using Artificial Neural Networks

Pneumatic systems are commonly used in industry processes and applications of automotion. These systems are make attractive power transmission with the compressed air, because of they are economic, clear, safe and simple structured.So in this systems, as noise and vibration effects, it’ s undesirable situations both human health and system performances yield and working life. In this study, vibration and noise datas are obtained from two type of pneumatic systems prototype which are classify metal and non-metal materials and performed an analysis with help of this datas and used neural network which has adaptive and quick contruction

Compressed Air Energy Storage-Part II: Application to Power System Unit Commitment

Unit commitment (UC) is one of the most important power system operation problems. To integrate higher penetration of wind power into power systems, more compressed air energy storage (CAES) plants are being built. Existing cavern models for the CAES used in power system optimization problems are not accurate, which may lead to infeasible solutions, e.g., the air pressure in the cavern is outside its operating range. In this regard, an accurate CAES model is proposed for the UC problem based on the accurate bi-linear cavern model proposed in the first paper of this two-part series. The minimum switch time between the charging and discharging processes of CAES is considered. The whole model, i.e., the UC model with an accurate CAES model, is a large-scale mixed integer bi-linear programming problem. To reduce the complexity of the whole model, three strategies are proposed to reduce the number of bi-linear terms without sacrificing accuracy. McCormick relaxation and piecewise linearization are then used to linearize the whole model. To decrease the solution time, a method to obtain an initial solution of the linearized model is proposed. A modified RTS-79 system is used to verify the effectiveness of the whole model and the solution methodology.Comment: 8 page