Papers by Keyword: Thermodynamic Performance

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Authors: Rui Duan, Guo Min Cui, Qun Zhi Zhu
Abstract: The advantage and application of NH3/CO2 cascade refrigeration system were analyzed . The principle and composition of cascade refrigeration system were outlined . The cascade refrigeration system using NH3 /CO2 as refrigerant were studied theoretically and the COP were calculated .
Authors: Xiang Gao, Jian Mei Feng, Yu Hong Shen, Xue Yuan Peng
Abstract: Increasing attention has been focused on capturing solution gas vented or flared from oil wells to reduce the emission of the greenhouse gases and effectively utilize the natural energy. With the aim of recovering the gas for its economic value, this paper presents a hermetic horizontal oil- injected scroll compressor to meet the unique demands of this application which the traditional compression technology has not been able to meet. A hermetic horizontal oil-injected scroll compressor was developed, in which the special internal oil system was designed. An experimental system was designed and set up to investigate the performance of the scroll compressor. With the experimental results, the effect of the discharge pressure and oil injection flow rate on performance of the compressor was analyzed and applied to provide the basis for developing reliable and flexible hermetic horizontal oil injected scroll compressor in taking use of the oil wells casing gas.
Authors: Yuan Gui Tang, Ai Qun Zhang
Abstract: A kind of shape memory alloy (SMA) differential drive method and its experiment equipment can be used in swing joint of a micro amphibious robot is presented. According to its motion character, motion principle of the swing joint differential driven by SMA is analyzed. The basic thermodynamic performance of the SMA springs with different structural parameters is researched by experimentation. Aiming at the SMA differential actuator composed by SMA springs in different structural parameters, experimental research and analysis on the response ability of the SMA actuator is carried out in various driving condition and environment, which can be used to provide experimental base and data support for applying SMA drive technique in propulsive area of underwater vehicles.
Authors: Zheng Chang, Lei Jia
Abstract: Using numerical simulation to study solar water heating system it will be fast to obtain data and have a reasonable conditional statistical forecast. In this paper, based on the numerical model of an actual forced circulation solar water heating system, the whole year thermodynamic performance in a forced circulation solar water heating system are simulated and studied. It is shown that the efficiency of energy utilization and the heat loss of collectors in the system are closely related with the out door temperature and main efforts should be on the collectors.
Authors: Hong Song Hu, Fang Wang, Jian Zhong Yu, Wu Hao
Abstract: This paper analysis on the design and the test of an air-conditioner hot water combined unit using environmental friendly refrigerant R407C. Firstly the research status of the system is elaborated for air-source heat pump water heater simply. Then the principle and structure are described on an air-conditioner heat pump followed by a water heater at different running modes and different operation conditions. The hot water experiments of the unit in three seasons have been tested and researched in a multi-functional environmental chamber. Some analysis of the unit’s thermodynamic performance is carried out from the test data for improving such kind of machine afterward.
Authors: Xin Le Yang, Wen Zhi Dai, Chang Zai Ren
Abstract: For recovering low temperature waste heat from industrial process efficiently, the organic Rankine cycle (ORC) was puts forward to use for thermal power generation. The flue gas parameter of waste heat from a cement kiln was set the research object and ORC system thermal analysis model was established using R123 as working fluid. A calculation program was carried and two main factors were given and the influence rules of thermodynamic performance were analyzed. The results show that the net work of system increases first and then decreased with the evaporating temperature and pressure and a parabolic rule is formed. The maximum net work is 4510kW and corresponding optimum evaporating temperature and optimal evaporating pressure are 140 °C and 1.46MPa respectively; The thermal efficiency increases with evaporating temperature and evaporating pressure increasing. The highest thermal efficiency can reach 12.68%.
Authors: Kyoung Hoon Kim, Hyung Jong Ko, Se Woong Kim
Abstract: In this study, thermodynamic performances of ammonia-water Rankine (AWR) cycle and regenerative Rankine (AWRR) cycle are comparatively investigated. Special attention is focused on the effects of ammonia concentration and turbine inlet pressure on the performance of system using heat sources of high temperature of 300 oC and low temperature of 150 oC. The behavior of important system variables including mass flow ratio of working fluid, net work production, and thermal efficiency are closely examined. Results show that performance characteristics for heat sources of high and low temperatures are quite different each other. For the high-temperature source, the thermal efficiency has a minimum in AWR system while it has a maximum in AWRR with respect to ammonia concentration in the range of 65% to 75%. For low-temperature source, however, the thermal efficiency decreases with ammonia concentration in the range of ammonia concentration higher than 95% for both AWR system and AWRR system and the effect of regenerator is negligible.
Authors: Xiao Dong Zhang, Da Peng Hu, Zong Chang Zhao
Abstract: In present research ionic liquid, 1,3-dimethylimidazolium dimethylphosphate ([MMIM][DMP]) and water were taken as the new working pair for absorption heat transformer (AHT). The thermodynamic cycle performance for this working pair was simulated based on its thermodynamic data, mass and energy balance for each component in a AHT. The effects of absorption and condensing temperature on the coefficient of performance (COP), exergy efficiency (ECOP), concentration deference between dense and dilution solutions and flow rate ratio were analyzed. The cycle performance comparison for AHT using two working pairs, H2O + [MMIM][DMP] and H2O + LiBr was carried out. The results indicate that the COP and ECOP of AHT for H2O+ [MMIM][DMP] are all lower than those for H2O + LiBr, but they can still reach 0.4 and 0.5 respectively when condensing and generation temperatures are 35 and 90 °C respectively. The excellent physical and chemical properties of ionic liquid mentioned above together with suitable cycle performance make this new working pair to have the potential application in absorption heat pump or absorption heat transformer.
Authors: Tuo Wang, Feng Wu, Jin Hua Fei, Ming Fang Liu
Abstract: Thermo-acoustic refrigerator is a new type of engine, which is based on the thermo-acoustic effect. A new model which expresses as an ellipse in pressure-volume diagram is established to investigate the thermodynamic performance of an actual thermo-acoustic refrigeration micro-cycle. The demarcation points of endothermic processes and exothermic processes in the actual micro-cycle are found. The analytic expressions of the dimensionless cooling load and the coefficient of performance (COP) are deduced. The relationship between the dimensionless cooling load and the COP are investigated by numerical examples. The results show that the dimensionless cooling load is a monotonically increasing function of the COP and the pressure amplitude.
Authors: Yan Song Wang, Hui He, Zhen Hua Xu, Jiang Hua Liu
Abstract: Exhaust gas recirculation (EGR) cooler plays an important role in reducing the nitrogen oxides (NOx) emission of diesel engines. By using the CFDesign software, in this paper, the finite element models are established for analyzing the thermodynamic performance of an EGR cooler. The temperature, velocity and pressure fields of the fluids in the EGR cooler are simulated and verified. Based on these models, furthermore, the thermodynamic performance of the EGR cooler with different structures of cooling tube are analyzed, compared and discussed. The results show that, under the fixed pressure boundary conditions, the EGR cooling efficiency can be significantly increased by properly design the fin number of the cooling tube in EGR coolers.
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