Advanced Materials Research Vols. 608-609

Abstract: This article introduces the specific application of central air conditioning chilled water storage technology in the actual central air conditioning engineered reconstruction. The author analyzes the energy-saving effect of application of central air conditioning chilled water storage technology and the economy of central conditioning renovation project. Operation cost comparison shows that water storage air conditioning system saves money more above 35% than conventional air conditioning system.

Abstract: Ni(OH)₂ xerogels were formed by sol-gel method at 80 °C followed drying at 110 °C and ambient pressure. The structure of Ni(OH)₂ xerogels was characterized using X-ray diffraction, transmission electron microscope (TEM) and N₂ (77K) adsorption. X-Ray Diffraction (XRD) results showed that the material obtained has a crystalline -Ni(OH)₂. TEM images showed that average size of the crystalline phase is about 10 nm. Results of N2 (77K) adsorption isotherm showed that the (BET) specific surface area is 232 m²/g and the Pore size distribution is in the regime 1-4 nm (Barrett–Joyner–Halenda, BJH). The Ni(OH)₂ xerogels electrodes were activated using cyclic voltammetry, and their capacitive performance was evaluated using cyclic voltammetry (CV) and constant current discharge. The Ni(OH)₂ xerogels electrodes exhibited excellent capacitive behavior with a specific capacitance of 635 F/g (calculated by CV). High performance obtained indicates that the Ni(OH)₂ xerogels are promising electrode materials for supercapacitors, and the electrochemical activation of these electrodes is doable.

Abstract: Flywheel energy storage has many advantages such as high specific energy, big specific power, small size, fast charge etc. This study describes the energy conversion control system of mag¬lev flywheel battery using PWM converter, established the model of control system. A circuit simulation of maglev flywheel battery electric energy conversion is proposed and discussed to verify the effectiveness of the design, which is of great significance for the development of flywheel energy conversion.

Abstract: The photovoltaic(PV) generation model and the wind power generation model are introduced in this paper. Taking the best economy and reliability of system operation as the objective functions and the system power balance and battery storage performance indices as the constraints, the optimal capacity of battery energy storage can be determined with the Tabu search algorithm. With the example system, the simulation results show that the proposed models and the algorithm are correct.

Abstract: A static frequency converter start-up control strategy for pumped-storage power unit is presented. And rotor position detecting without position sensor is realized according to voltage and magnetism equations of ideal synchronous motor mathematics model. The mechanism and implementation method of initial rotor position determination and rotor position estimation under low frequency without position sensor are expounded and validated by simulations. Based on the mentioned control strategy, first set of a static frequency converter start-up device in China for large-scale pumped-storage unit is developed, which is applied to start-up control test in the 90 MW generator/motor of Panjiakou Pumped-storage Power Plant. Test results show that rotor position detecting, pulse commutation, natural commutation, and unit synchronous procedure control of static start-up are all proved. The outcomes have been applied in running equipment, which proves the feasibility of mentioned method.

Abstract: It is an effective method to solve the contradiction between power supply and demand by using battery energy storage power station to adjust the load to keep balance. The kind and capacity of storage battery were selected based on its current application. Compared with multiple storage battery series-parallel connect modes, the paper proposed a connection mode using the combination of series and parallel. Designed a storage battery charge and discharge control system based on SVPWM technology, which includes hardware circuit and software design. Simulated the system through MATLAB and analyzed the wave shape, it proves that the circuit topology structure is validity and have a reliable control effect, and the energy storage power station achieves better load shifting effect on the power balance.

Abstract: Based on the performance of energy storage air conditioning system, a small heat pump water heat storage air conditioner was designed with some experiments in winter running. The experiments show that the heat storage system can improve inlet temperature of the refrigerating compressor effectively when proceeding heating mode, and the outlet temperature is also higher relatively; In the low-temperature heating condition, the maximum heating capacity can up to more than the rated heating capacity and the defrosting performance is better too; But the heat storage capacity of the system is quite limited for the thermal storage material is water.

Abstract: The energy-saving effect of the injection molding machine energy-saving reformation project was measured in a factory. Based on the analysis of the project energy-saving principle, analyzed the energy-saving rate of the reformed injection molding machine in case of producing different products. The test results show that the active power saving rate is 50% under the load condition, the active power saving rate is more than 75% under the no-load condition and energy-saving effect is more obvious under the no-load condition. Finally, analyzed the power quality impact caused by the energy-saving equipment on the distribution network, put forward some suggestions for improvement.

Abstract: In this paper, K-means clustering algorithm of data mining technology is applied to determine the targeted value. The historical operation data of 600MW unit boiler are studied to determine the boiler combustion optimization target values of different conditions. The normalized method is used for handling data, directly reflects the position of operation target value in the whole parameter range, provides guide for boiler combustion optimization.

Abstract: The heat transfer enhancement in a latent heat energy storage device through embedment of copper foam (CF) is reported. The CF had a 96% porosity and the phase change material (PCM) was 25# paraffin. The CF and PCM were contained in a cuboid sample. A prototype test room was designed to numerically investigate the performance of the device. The melting and freezing process of the PCM and the day-night temperature of the room were observed. The results show that the tested totally melting time of the PCM is 8.72 hours during the daytime while the freezing time is 8.19 hours at night, and the phase change process could accomplish within 8-9 hours. The maximum temperature difference of the room is reduced 8.3°C. The room comfort could be significantly enhanced under the premise of less air conditioning energy consumption by applying the device.