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AbstractSwitchable exhaust air (SEA) window allows the exhaust air from HVAC system to be ventilated through the cavity of the window to ambient. It can be regarded as an exhaust air heat recovery device in buildings. The annual energy requirement of the window has been calculated in Wuhan, China. The energy requirements for conditioning fresh air with and without the total heat recovery ventilators (THRVs) are also investigated. Heat recovery performance of the SEA window and the THRVs is compared. Results show that the SEA window can potentially provide alternative solution for recovering the low-grade energy from air-conditioning exhaust air.

Abstract Uncertainties of cooling load may make cooling system oversized. Most of previous studies implement probabilistic-based uncertainty analysis, intending to achieve optimization and reliability simultaneously. However, how to reduce the load uncertainty has received little attention. This paper investigates the impact of water storage on the design of cooling system considering load uncertainty. Information entropy is used as a convergence index of load uncertainty and used to determine how many random simulations should to be performed. A cooling system configured with water storage (system B) and another system without water storage (system A as a comparation system) are investigated in this paper. In this paper, the configure of system A and system B are optimized respectively. The result shows that the capacity distribution of system A is consistent with the distribution of extreme loads. But, the capacity distribution of system B is more concentrated as the water storage can reshape the load curve. Water storage improves the flexibility of system B. Therefore, system B is more reliable and economical than system A.

AbstractThe increment of energy costs and decreasing prices of turbines generator and photovoltaic (PV) panels caused photovoltaic/wind hybrid system (PWHS) utilization is becoming popular. This paper presents a new topology of PWHS. It is consists of two main parts: the cooling system for photovoltaic module and the combination method of Savonius and Darrieus for wind turbine. The PWHS is installed in front of Centre of Excellence for Renewable Energy (CERE), University Malaysia Perlis, Northern Malaysia. The main energy source of this system is gain from PV array and wind power generation. It is well known that the power and efficiency of photovoltaic (PV) module usually falls at the rate of ∼0.5%/°C and ∼0.05%/°C respectively as increase of ambient temperature. The electrical efficiency of PV cell depends on its operating temperature during absorption of solar radiation. For this reason, an active PV cooling system was design using the DC brushless fan with inlet/outlet manifold for uniform airflow distribution. It was attached at the back of the PV panel. Where else, the improvement of wind is using Vertical Axis Hybrid Wind Turbine (VAWT) through the combination method of Savonius and Darrieus types. From the results, it shows that the improvement of PWHS give the big advantages in term of supply the energy in Perlis.

Abstract Global primary energy consumption will continue to increase with a high rate to 2050, which will be a big challenge for countries to meet both global and regional energy demand. Pumped storage stations (PSS) integrated to a hybrid power system (HPS) with solar and wind power for China are under construction to tussle with this challenge. Historically, modeling of a PSS integrated HPS has been ignored the interaction effect between the shaft vibration and the governing strategies, which will increase the dynamic risk of PSS disconnected immediately to HPS. Here we unify the models of the hydro-turbine governing system and hydro-turbine generator units with a novel expression of hydraulic forces. We quantize all the parameter’s interaction contributions of PSS integration to HPS and validate this model with the existing models. Finally, we show the feasibility of PSS’s model in integrating of a HPS under steady and fault scenarios.

AbstractThis paper presents the experimental plans and designs as well as examples of predictive modeling of a pilot-scale CO2 injection experiment at the Heletz site (Israel). The overall objective of the experiment is to find optimal ways to characterize CO2 -relevant in-situ medium properties, including field-scale residual and dissolution trapping, to explore ways of characterizing heterogeneity through joint analysis of different types of data, and to detect leakage. The experiment will involve two wells, an injection well and a monitoring well. Prior to the actual CO2 injection, hydraulic, thermal and tracer tests will be carried out for standard site characterization. The actual CO2 injection experiments will include (i) a single well injection-withdrawal experiment, with the main objective to estimate in-situ residual trapping and (ii) a two-well injection-withdrawal test with injection of CO2 in a dipole mode (injection of CO2 in one well with simultaneous withdrawal of water in the monitoring well), with the objective to understand the CO2 transport in heterogeneous geology as well as the associated dissolution and residual trapping. Tracers will be introduced in both experiments to further aid in detecting the development of the phase composition during CO2 transport. Geophysical monitoring will also be implemented. By means of modeling, different experimental sequences and injection/withdrawal patterns have been analyzed, as have parameter uncertainties. The objectives have been to (i) evaluate key aspects of the experimental design, (ii) to identify key parameters affecting the fate of the CO2 and (iii) to evaluate the relationships between measurable quantities and parameters of interest.

AbstractPre-drying is a potential way to improve the electric generation efficiency of lignite-fired power plant, and steam is a main kind of drying heat source. In conventional pre-dried lignite-fired power system, the steam extraction of regenerative system is led to the dryer directly. The steam extraction must be used by the dryer after throttling, if the energy mismatch exists between the supply of steam extraction and the need of dryer. Two systems of energy supply for the dryer, that the energy of the steam extraction is supplied to the dryer via compressor or ejector, were proposed in this paper to further increase the energy utilization efficiency. These systems were thermodynamic analyzed, and the electric generation efficiencies of these systems were compared. The energy saving boundary was gotten.

Abstract In order to further promote the development of the new energy vehicle industry, Parallel Management regulation for corporate average fuel consumption and new energy vehicle credits for passenger vehicles (dual-credit scheme) have been proposed by Ministry of Industry and Information Technology in September 2017. This study attempted to investigate the impact of dual-credit scheme on the penetration of new energy vehicles and the short-term strategies of the automotive industry. For this purpose, a market analysis model is proposed based on game theory and the credit market equilibrium to quantify the effects of the credit trading mechanism. Four categories of automakers are considered. The obtained results show that: (i) The dual-credit scheme is indeed an effective policy solution that enables the expansion of the volume of NEV market. (ii) The dual-credit scheme can accelerate the elimination of outdated technologies with lower driving mileage, and it can also promote the adoption of technologies with longer driving mileage. (iii) The dual-credit scheme allows all automakers to achieve their targets in a market efficient manner.

AbstractFor on-line monitoring and controlling the quality of resistance spot welding, we design a high speed data acquisition and spot welding signal processing system. System hardware, which are made up of PLC 1800 high speed data acquisition card current sensor voltage sensor signal adjust circuit and IPC, is mainly responsible for A/D conversion and data acquisition; software system are mostly made up of data acquisition and memory module wavelet filtering of digit signal module U-I image and energy analyze module in electric signal of spot welding, which realize the data acquisition and processing base on welding current electrode voltage welding cycle. The experimental result showed that U-I image shape of different material are markedly dissimilar in spot welding, according to U-I image we can check if welding current and electrode voltage are normal in welding process or not, and through U-I image we can read the input energy of every U-I curve half-cycle and judge spot welding quality. Therefore, we can take U-I image monitoring method in spot welding quality monitoring of different material.