An LES simulation of flow over an accumulator unit of an underwater compressed air energy storage facility was conducted. The accumulator unit consists of three touching underwater balloons arranged in a floral config...An LES simulation of flow over an accumulator unit of an underwater compressed air energy storage facility was conducted. The accumulator unit consists of three touching underwater balloons arranged in a floral configuration. The structure of the flow was examined via three dimensional iso surfaces of the Q criterion. Vortical cores were observed on the leeward surface of the balloons. The swirling tube flows generated by these vortical cores were depicted through three dimensional path lines. The flow dynamics were visualized via time series snapshots of two dimensional vorticity contours perpendicular to the flow direction; revealing the turbulent swinging motions of the aforementioned shedding-swirling tube flows. The time history of the hydrodynamic loading was presented in terms of lift and drag coefficients. Drag coefficient of each individual balloon in the floral configuration was smaller than that of a single balloon. It was found that the total drag coefficient of the floral unit of three touching balloons, i.e. summation of the drag coefficients of the balloons, is not too much larger than that of a single balloon whereas it provides three times the storage capacity. In addition to its practical significance in designing appropriate foundation and supports, the instantaneous hydrodynamic loading was used to determine the frequency of the turbulent swirling-swinging motions of the shedding vortex tubes; the Strouhal number was found to be larger than that of a single sphere at the same Reynolds number.展开更多
A system of energy storage for solar thermal air conditioning combined with ejector cooling system for residential is determined in this paper. The purpose of this study is to design the energy storage system for heat...A system of energy storage for solar thermal air conditioning combined with ejector cooling system for residential is determined in this paper. The purpose of this study is to design the energy storage system for heating the water in a storage tank to reach the required temperature for exchanging heat with the refrigerant of cooling system. The design from calculation of thermal energy storage system that proper with the solar flat plate collector area results are 70 m2, and the hot water temperature is over than 80 ℃. A cooling system is selected for refrigerant of R141b from the solar air conditioning system of 10.5 kW, and the energy source is solar thermal energy from the collector that there is an efficiency of 0.46 approximately. This storage system for the electric solar cooling system can be reduced the problem of the intermittent of energy source with the constant generating temperature to run the cooling system continuously.展开更多
A power system with proton exchange membrane fuel cells (PEMFC) was designed for thermal underwater glider.Heat generated by PEMFC is used as the propulsion power of the glider,and the electricity is used in the contr...A power system with proton exchange membrane fuel cells (PEMFC) was designed for thermal underwater glider.Heat generated by PEMFC is used as the propulsion power of the glider,and the electricity is used in the control and sensor system.An electric energy storage system (ESS) is required which possesses high power density with good cycle life.Ultracapacitors which exhibit high power density and cycle life are considered as energy storage devices.Simulations based on a specific voyage condition indicate that ESS with ultracapacitors has positive effects on reducing the output power demand of PEMFC and lightening the power system.Experimental results show that the state of charge (SOC) is related to the capacitance and resistance in ultracapacitor ESS.展开更多
The financial viability of a solar STES （seasonal thermal energy store） installed in a mixed commercial and residential multiunit development of low-energy buildings located in Lysekil, Sweden, a maritime Scandinavi...The financial viability of a solar STES （seasonal thermal energy store） installed in a mixed commercial and residential multiunit development of low-energy buildings located in Lysekil, Sweden, a maritime Scandinavian Climate has been investigated. Using recorded figures for the installation costs and performance, a financial life cycle analysis has been undertaken to determine the cost effectiveness of the system. The time value of money is considered and an LCC （life cycle cost） analysis undertaken to identify the cost-effectiveness of the solution. It shows that while a direct heating and hot water system incorporating STES can be economically viable in a Swedish maritime climate in the long term, assistance such as that provided by government incentives is required to assist with the high capital cost of the initial investment.展开更多
文摘An LES simulation of flow over an accumulator unit of an underwater compressed air energy storage facility was conducted. The accumulator unit consists of three touching underwater balloons arranged in a floral configuration. The structure of the flow was examined via three dimensional iso surfaces of the Q criterion. Vortical cores were observed on the leeward surface of the balloons. The swirling tube flows generated by these vortical cores were depicted through three dimensional path lines. The flow dynamics were visualized via time series snapshots of two dimensional vorticity contours perpendicular to the flow direction; revealing the turbulent swinging motions of the aforementioned shedding-swirling tube flows. The time history of the hydrodynamic loading was presented in terms of lift and drag coefficients. Drag coefficient of each individual balloon in the floral configuration was smaller than that of a single balloon. It was found that the total drag coefficient of the floral unit of three touching balloons, i.e. summation of the drag coefficients of the balloons, is not too much larger than that of a single balloon whereas it provides three times the storage capacity. In addition to its practical significance in designing appropriate foundation and supports, the instantaneous hydrodynamic loading was used to determine the frequency of the turbulent swirling-swinging motions of the shedding vortex tubes; the Strouhal number was found to be larger than that of a single sphere at the same Reynolds number.
文摘A system of energy storage for solar thermal air conditioning combined with ejector cooling system for residential is determined in this paper. The purpose of this study is to design the energy storage system for heating the water in a storage tank to reach the required temperature for exchanging heat with the refrigerant of cooling system. The design from calculation of thermal energy storage system that proper with the solar flat plate collector area results are 70 m2, and the hot water temperature is over than 80 ℃. A cooling system is selected for refrigerant of R141b from the solar air conditioning system of 10.5 kW, and the energy source is solar thermal energy from the collector that there is an efficiency of 0.46 approximately. This storage system for the electric solar cooling system can be reduced the problem of the intermittent of energy source with the constant generating temperature to run the cooling system continuously.
基金Supported by the State Key Program of National Natural Science Foundation of China (No. 50835006)Science & Technology Support Planning Foundation of Tianjin (No. 09ZCKFGX03000)
文摘A power system with proton exchange membrane fuel cells (PEMFC) was designed for thermal underwater glider.Heat generated by PEMFC is used as the propulsion power of the glider,and the electricity is used in the control and sensor system.An electric energy storage system (ESS) is required which possesses high power density with good cycle life.Ultracapacitors which exhibit high power density and cycle life are considered as energy storage devices.Simulations based on a specific voyage condition indicate that ESS with ultracapacitors has positive effects on reducing the output power demand of PEMFC and lightening the power system.Experimental results show that the state of charge (SOC) is related to the capacitance and resistance in ultracapacitor ESS.
文摘The financial viability of a solar STES （seasonal thermal energy store） installed in a mixed commercial and residential multiunit development of low-energy buildings located in Lysekil, Sweden, a maritime Scandinavian Climate has been investigated. Using recorded figures for the installation costs and performance, a financial life cycle analysis has been undertaken to determine the cost effectiveness of the system. The time value of money is considered and an LCC （life cycle cost） analysis undertaken to identify the cost-effectiveness of the solution. It shows that while a direct heating and hot water system incorporating STES can be economically viable in a Swedish maritime climate in the long term, assistance such as that provided by government incentives is required to assist with the high capital cost of the initial investment.
