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This paper explores how the energy storage capacity required by an electric grid increases with the penetration of renewable generation. The paper uses the UK as a case study and aims to quantify the amount and duration of energy storage that the country will need to fully decarbonize its electric supply. The paper also studies the effect that the mix of renewables (wind + solar) has on the storage capacity needed and highlights that a greater mismatch between the generation and demand profiles will require a larger energy storage capacity. Therefore the right generation mix for the region should be used. Results show that the UK will need a storage capacity of approximately 7.63 TWh (~4 days) to achieve an overall renewable penetration of 100%. Two important considerations are made: i) the mix between wind and solar is 79–21% and ii) a 5% of over-generation (and curtailment) is allowed. Assuming that the storage capacity is provided by compressed air systems (CAES) and considering the current costs of renewable generation, this scenario attains a levelized cost of electricity of ~61 £/MWh. This scenario achieves the lowest possible LCOE despite the fact that 5% of the generated electricity is wasted and still paid-for. If a strict rule of zero-net curtailment was in place, the storage capacity required would almost double (14.93 TWh) and the final cost of electricity would be ~2.3% higher.

Compressed air is an attractive energy storage solution that can address many of the problems associated with operating large electricity grids with high levels of renewable penetration. The mature nature of the technology makes compressed air a robust and cheap alternative to batteries that is particularly applicable to offshore generation. Storage tanks (pressure vessels) must be utilised if geological alternatives, such as solution mined salt caverns, are not available or cannot be excavated in a particular deployment. Tanks are typically expensive, however it is possible to realise significant improvements (over 50%) in cost per unit exergy stored if “real gas effects” of air are exploited. Economic benefits resulting from realistic air property dependencies rely on storing air at low temperatures, circa −40°C. In this temperature range concerns are raised over the integrity of common pressure vessel materials; a transition from ductile to brittle failure modes is observed in many BCC (body centred cubic) steels that limits the size of “safe” (non-propagating) flaws in the vessel and increases the potential for fast fracture/catastrophic failure. Autofrettage is a manufacturing process in which a beneficial compressive stress state at the internal wall of a pressure vessel is induced by over pressurising the cylinder during manufacture. Autofretteage allows larger flaws or defects (such as cracks) to be safely accommodated in a design, compared to an identical vessel that has not undergone autofrettage. In this work autofrettage is investigated as a method which can allow cold compressed air energy storage to be realised. Safe operating pressures and temperatures are determined for vessels that have undergone autofrettage. These are then compared to similar calculations for more “simple” vessel designs (i.e. without autofrettage) and economic arguments are developed for the adoption of cold compressed air storage. Costings (cost per unit exergy stored) are not significantly sensitive to the additional effort required to autofrettage a vessel (due to the pressure levels involved).

Underwater Compressed Air Energy Storage takes advantage of the hydrostatic pressure in deep water to provide a means of storing large amounts of pressurized air without expending very large sums of money on pressure containments. A key attractive feature of all underwater storage of pressurised air is that the containment may be largely isobaric (i.e. the pressure of the stored air remains relatively constant irrespective of the level of fill). One of the common issues for isobaric containments is air dissolution into water. The dissolution is controlled by the concentration of the air in the water and Henry's law can be applied to determine the steady-state concentration of dissolved air in seawater. The charge/discharge process is clearly dynamic. In dynamic processes, steady state is never reached. This paper examines whether the dynamic effects may be useful. Experiments are performed to investigate air dissolution in a water tank. The results reveal that the mass of the air dissolved in water in first 0.1s accounts for 97.5% of total mass determined by Henry's law. This means time of air dissolution is in the order of 0.1s. UWCAES systems are often used for long duration energy storage in the order of hours. The time of air dissolution is short enough to cause air loss in UWCAES systems.

Miniaturize multifunctional tilting type aircraft has both a VTOL capability and high cruise performance, which is significant in commercial and industrial fields. In this paper, a Y6 tilt rotor UAV is selected as the research object after comparing three kinds of most widely adopted tilting type UAVs. Research status and technical difficulties of tilt rotor aircraft in transition process are introduced, and the general properties of the Y6 tilt rotor prototype are given first. Then the multi-body mathematical model for the aircraft is derived, in which the mass of tilting mechanism and the tilting of high-speed rotating rotors is considered. After that the control strategy for the transition process is designed. Numerical simulation of transition process is built and the influence of tilt angular velocity and initial flight speed on the stability of tilting process is analyzed in order to find the optimal tilting control strategy. Finally, the mechanical structure and flight control system of the prototype are introduced, flight test results are shown to demonstrate that proposed optimal tilting control strategy make the aircraft perform stable in the transition process.

In this paper, the influence of the tilting-rotor structure parameters on the aerodynamic characteristics of a small tilt rotor unmanned aerial vehicle (UAV) is studied. The simplified model of tilt rotor unmanned aerial vehicle (UAV) is established by using SolidWorks software, and the model is divided into unstructured grid by ICEM software. Finally, set the corresponding boundary conditions in the FLUENT software and then simulated. By simulating the flight state of the tilt rotor unmanned aerial vehicle (UAV) in the fixed wing mode, the lift-drag aerodynamic characteristics of the aircraft in that flat flight mode are obtained. On the other hand, researched the effect of the tilting angle of the tilting-rotor mechanism, the size of the multi-rotor structure (the distance of the tilting-rotor mechanism from the fixed wing), and the rotor installation distance of the coaxial twin propeller mechanism on the complex flow field between rotor and fixed wing. Obtained some meaningful conclusions, which are useful for the future design of the small tilt rotor unmanned aerial vehicle.

As one of the most important nursing interventions of ventilated patients' respiratory tract, secretion clearance is usually used to keep the respiratory tract clear, improve alveolar ventilation and patients' breathing function. However, the existing secretion clearance technologies have serious defects in efficiency, safety and automation. Considering these disadvantages above, this paper proposes an intelligent secretion system, which combines doctors' theoretical knowledge, clinical experience and engineering technology. In this system, three key technologies will be broken through to form a set of simple, safe, efficient and automatic secretion clearance technology, which are 1. On-line identification technology of the time when to clear secretion; 2.1ntelligent control technology of the secretion clearance system based on simulation of the human natural cough; 3. Breathing simulation technology with self-learning function. This system will provide an intelligent method to keep patients' respiratory tract clear, prevent respiratory system infection, avoid the damage to respiratory tracts and ensure mechanical ventilation treatment goals. The technology proposed in this paper is poised to replace catheter suction technology as the most common secretion clearance technology in clinic. Ultimately, this technology will improve the secretion clearance technology level of China, save lives of ventilated patients', reduce patients' pain and the work intensity of medical staffs.

Now many remote or underserved areas have brought forward a high demand for improving the quality of ECG interpretation. Telediagnosis can provide a feasible solution. However, even communities already equipped with ECG machines cannot communicate with a remote diagnostic center, because these machines lack interoperability. It can be predicted that the applicability and popularization of ECG telediagnosis could be greatly improved via developing high interoperable ECG machines and realizing a direct interaction between the machines and a remote diagnostic center. In this paper, a detail analysis on the flow of ECG telediagnosis is represented first. Several interactive transactions and a complete and reasonable interaction workflow of ECG machine are designed on the base of the analysis. The design has realized an automatic acquisition of patient information and the transmission of a complete ECG record as well as a diagnostic report. We have created an ECG machine based on the design presented and developed a Web Service named TeleECGService, through which a direct interaction between an ECG machine and a remote diagnostic center can be achieved. An ECG remote diagnosis system based such high interoperable ECG machines has been put into use in a hospital in Shanxi Province of China.

In this paper, case of E-Bayes method to forecast investment is given. Data are grouped, and the probability of samples that does not drop into the state is assumed. An increasing function to establish the forecast model for investment is constructed. Finally, calculations are carried out according to the practical problems, and result shows that the E-Bayes method is feasible and easy to operate.