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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.

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.

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.

AbstractIndoor environmental control has been proved to be critical for long-term preservation for artifacts in archaeology museums. However, it is usually a very energy intensive process to sustain a steady condition continuously throughout the year for the whole exhibition hall. In this study, an energy efficient strategy that only controls the local environment for the preservation area is proposed. A laboratory room with a funerary pit was constructed to simulate a large open exhibition hall. Experimental investigations using the test pit, with radiant panels and air curtain system for control of the local environment for the funerary pit, validated this management strategy for the preservation of relics in archaeology museums. The results show that using both an air curtain and a radiant heating system provides a feasible and energy-saving strategy for controlling the preservation environment independently.

Abstract The energy revolution will affect the development and utilization of energy, the production and distribution of electricity, and then has profound impacts on the function and form of the power grid. In this paper, to analyze the impacts of energy revolution in China, we generator of electric system planning (GESP) model to simulate energy structures and layouts that simulate different scenarios. Then we improve the calculation methods of the index scores and weights to improve the TOPSIS evaluation method, composing a comprehensive assessment system of TOPSIS-AHP-Entropy method. Furthermore, we construct a multi-dimensional evaluation index system that includes economics, technology, and environmental protection. The assessment results of two scenarios demonstrate, in the context of the energy revolution, that the Reinforcement scenario with large-scale renewable energy, has much better benefits, which requires the grid stronger, more efficient, cleaner. In the new energy revolution, there are four main changes of the morphological positioning and functional patterns of future power grid.

Abstract The state-of-charge (SOC) and state-of-health(SOH) are two critical indexes in battery management system (BMS) for electric vehicles(EVs). To achieve accurate estimation of SOC and SOH, this paper establishes a battery equivalent circuit model and uses Forgetting Factor Recursive Least Squares (FFRLS) to realize online identification of model parameters. And based on the relationship between the ohmic internal resistance and the SOH, a joint estimator using Double extended Kalman filter(DEKF) algorithm is proposed for the estimation of both SOC and SOH. Then, an error model is established to analyze the influence of the battery OCV-SOC curve, battery capacity and battery parameters on the estimation of the SOC and SOH. The experiment results show that the maximum estimation error of SOC and SOH is 1.08% and 1.52% respectively, which have verified that accurate and robust SOC and SOH estimation results can be obtained by the proposed method. Besides, the OCV-SOC curve has the greatest influence on the estimation error of SOC and SOH among the three kinds of factors mentioned above.

Abstract Renewable generation technologies (e.g. photovoltaic panels (PV)) are often installed in buildings and districts with an aim to decrease their carbon emissions and consumption of non-renewable energy. However, due to a mismatch between supply and demand at an hourly but also on a seasonal timescale; a large amount of electricity is exported to the grid rather than used to offset local demand. A solution to this is local storage of electricity for subsequent self-consumption. This could additionally provide districts with new business opportunities, financial stability, flexibility and reliability. In this paper the feasibility of hydrogen based electricity storage for a district is evaluated. The district energy system (DES) includes PV and hybrid photovoltaic panels (PVT). The proposed storage system consists of production of hydrogen using the renewable electricity generated within the district, hydrogen storage, and subsequent use in a fuel cell. Combination of battery storage along with hydrogen conversion and storage is also evaluated. A multi-energy optimization approach is used to model the DES. Results of the model are optimal battery capacity, electrolyzer capacity, hydrogen storage capacity, fuel cell capacity and energy flows through the system. The model is also used to compare different system design configurations. The results of this analysis show that both battery capacity and conversion of electricity to hydrogen enable the district to decrease its carbon emissions by approximately 22% when compared to the reference case with no energy storage.