The energy saving issue of chilled water system in an intelligent building is analyzed from the systematic point of view, and an optimum scheduling scheme which can save energy of the system facilities and satisfy the...The energy saving issue of chilled water system in an intelligent building is analyzed from the systematic point of view, and an optimum scheduling scheme which can save energy of the system facilities and satisfy the constraints of the real time cold loads and system running is also proposed. It can make the minimum cost of the system by optimizing the number of running chillers, running parameters and the distribution of real time loads of running chillers. The improved genetic algorithm is used in the optimum scheduling scheme. The computation results show that the building energy consumption can be decreased by about 10%.展开更多
A motion parameter optimization method based on the objective of minimizing the total energy consumption in segment positioning was proposed for segment erector of shield tunneling machine. The segment positioning pro...A motion parameter optimization method based on the objective of minimizing the total energy consumption in segment positioning was proposed for segment erector of shield tunneling machine. The segment positioning process was decomposed into rotation, lifting and sliding actions in deriving the energy calculation model of segment erection. The work of gravity was taken into account in the mathematical modeling of energy consumed by each actuator. In order to investigate the relationship between the work done by the actuator and the path moved along by the segment, the upward and downward directions as well as the operating quadrant of the segment erector were defined. Piecewise nonlinear function of energy was presented, of which the result is determined by closely coupled components as working parameters and some intermediate variables. Finally, the effectiveness of the optimization method was proved by conducting a case study with a segment erector for the tunnel with a diameter of 3 m and drawing comparisons between different assembling paths. The results show that the energy required by assembling a ring of segments along the optimized moving path can be reduced up to 5%. The method proposed in this work definitely provides an effective energy saving solution for shield tunneling machine.展开更多
The study examined joint discontinuity spacing effect on drilling condition and performance in selected rocks in llorin and Ibese areas, Nigeria. Five samples for each rock type （gneiss and limestone） were tested in...The study examined joint discontinuity spacing effect on drilling condition and performance in selected rocks in llorin and Ibese areas, Nigeria. Five samples for each rock type （gneiss and limestone） were tested in the laboratory for chemical, physical and mechanical properties. Dip direction and joint spacing were measured using compass clinometers. The chemical composition was determined using X-ray Fluores- cence （XRF） spectrometer. The results show that gneiss has SiO2 of 61.88g and limestone has CaO content of 52.3g. The average dry density of gneiss and limestone are 2.6 and 2.39 g/cm^3, respectively. The uniaxial compressive strength of gneiss and limestone are 195 and 93.83 MPa, respectively. These rocks are classified as strong and moderately strong rock. Gneiss and limestone have mean joint discontinuity spacing of 0.79 and 0.25 m, which classified them as moderate and wide joint spacing respectively. Joint spacing was correlated with specific energy, bit wear and uniaxial compressive using Statistical Package for Social Science （SPSS）. The regression model has multiple coefficient of correlation of R^2 = 0.791 and R^2 =0.995 for gneiss and limestone, respectively. The variation in joint spacing could be attributed to spe- cific energy, bit wear and uniaxial compressive strength which affect drilling condition and performance. Ultimately, as joint spacing gets closer, the drilling velocity increases, drill string will be stable.展开更多
目前,我国标准中提出评价冷水机组节能性能的指标主要有性能系数(Coefficient of Performance, COP)、综合部分负荷性能系数(Integrated Part Load Value, IPLV)和非标准部分负荷性能系数(Non-Standard Part Load Value, NPLV)。IPLV/N...目前,我国标准中提出评价冷水机组节能性能的指标主要有性能系数(Coefficient of Performance, COP)、综合部分负荷性能系数(Integrated Part Load Value, IPLV)和非标准部分负荷性能系数(Non-Standard Part Load Value, NPLV)。IPLV/NPLV作为冷水机组部分负荷性能系数性能评价指标有着重要意义,但是在实际使用中也存在着局限。本文借鉴IPLV/NPLV提出了RPLV(Real Part Load Value, RPLV)计算公式确定方法,可以解决IPLV/NPLV使用过程中的局限,包括(1)可以反映特定项目的实际工况;(2)可以反映多台机组在特定运行策略下的运行情况;(3)可以用该指标简单估算冷水机组实际能耗。同时,本文通过实际工程案例对RPLV计算方法进行了实践应用,证明该方法是切实可行的。此外,本文还对RPLV和IPLV/NPLV从负荷区间划分、权重系数、测试工况、能耗估算适用性等方面进行了关键要素对比分析,总结了RPLV的对比IPLV/NPLV的相同与不同之处,为RPLV的实际应用提供参考借鉴。展开更多
The reliable assessment of the annual energy demand has become necessary in view of building energy performance certification. Accurate models must be used to simulate the behaviour of HVAC （heating, ventilation and ...The reliable assessment of the annual energy demand has become necessary in view of building energy performance certification. Accurate models must be used to simulate the behaviour of HVAC （heating, ventilation and air conditioning） components in real operation, usually characterized by a wide variation of building loads. In this context, this paper deals with the development and validation of an algorithm aimed at the assessment of part load performance of various kinds of controls for vapour compresion based heat pumps and chillers, in particular referring to on-off, inverter-driven and multi-stage vapour compression. The reliability of this algorithm in the calculation of seasonal performances is checked against monitoring of heat pumps and chillers operating under real conditions.展开更多
ASHP （air source heat pump） water heater is a renewable and energy efficient device used for sanitary hot water production. The system comprises of a storage tank and heat pump connected by pipes. These major units ...ASHP （air source heat pump） water heater is a renewable and energy efficient device used for sanitary hot water production. The system comprises of a storage tank and heat pump connected by pipes. These major units can either be compact as in the integrated model or split as in the retro-fit model. In this research, the analysis of energy losses was performed using SIRAC （the Southern African refrigeration and air conditioning） residential split type heat pump of 1.2 kW input power to retrofit a 200 liter high pressure kwikhot storage tank without hot water being drawn off for the entire monitoring period. Likewise to experimentally determine the losses DAS （data acquisition system） was designed and built to measure Ta （ambient temperature; RH-relative humidity）, RH, To （ASHP outlet water temperature）, Ti （ASHP inlet water temperature） and Vh. （volume of water heated by ASHP unit）.The results showed that the heat energy gain to compensate standby losses could range from 1.8 kWh to 2.1 kWh with the corresponding electrical energy used by ASHP water heater ranging from 0.55 kWh to 0.66 kWh. The standby losses depend primarily on the Vh, the Ta and the RH while the influence of （To - Ti） is secondary. The results can be of valuable interest to manufacturer of retrofit ASHP unit for hot water production when matching the electrical energy required to compensate for the standby losses.展开更多
文摘The energy saving issue of chilled water system in an intelligent building is analyzed from the systematic point of view, and an optimum scheduling scheme which can save energy of the system facilities and satisfy the constraints of the real time cold loads and system running is also proposed. It can make the minimum cost of the system by optimizing the number of running chillers, running parameters and the distribution of real time loads of running chillers. The improved genetic algorithm is used in the optimum scheduling scheme. The computation results show that the building energy consumption can be decreased by about 10%.
基金Project(51305328)supported by the National Natural Science Foundation of ChinaProject(2012AA041803)supported by the NationalHigh Technology R&D Program of China+1 种基金Project(GZKF-201210)supported by the Open Fund of State Key Laboratory of Fluid Power Transmission and Control of Zhejiang University,ChinaProject(2013M532031)supported by the China Postdoctoral Science Foundation
文摘A motion parameter optimization method based on the objective of minimizing the total energy consumption in segment positioning was proposed for segment erector of shield tunneling machine. The segment positioning process was decomposed into rotation, lifting and sliding actions in deriving the energy calculation model of segment erection. The work of gravity was taken into account in the mathematical modeling of energy consumed by each actuator. In order to investigate the relationship between the work done by the actuator and the path moved along by the segment, the upward and downward directions as well as the operating quadrant of the segment erector were defined. Piecewise nonlinear function of energy was presented, of which the result is determined by closely coupled components as working parameters and some intermediate variables. Finally, the effectiveness of the optimization method was proved by conducting a case study with a segment erector for the tunnel with a diameter of 3 m and drawing comparisons between different assembling paths. The results show that the energy required by assembling a ring of segments along the optimized moving path can be reduced up to 5%. The method proposed in this work definitely provides an effective energy saving solution for shield tunneling machine.
文摘The study examined joint discontinuity spacing effect on drilling condition and performance in selected rocks in llorin and Ibese areas, Nigeria. Five samples for each rock type （gneiss and limestone） were tested in the laboratory for chemical, physical and mechanical properties. Dip direction and joint spacing were measured using compass clinometers. The chemical composition was determined using X-ray Fluores- cence （XRF） spectrometer. The results show that gneiss has SiO2 of 61.88g and limestone has CaO content of 52.3g. The average dry density of gneiss and limestone are 2.6 and 2.39 g/cm^3, respectively. The uniaxial compressive strength of gneiss and limestone are 195 and 93.83 MPa, respectively. These rocks are classified as strong and moderately strong rock. Gneiss and limestone have mean joint discontinuity spacing of 0.79 and 0.25 m, which classified them as moderate and wide joint spacing respectively. Joint spacing was correlated with specific energy, bit wear and uniaxial compressive using Statistical Package for Social Science （SPSS）. The regression model has multiple coefficient of correlation of R^2 = 0.791 and R^2 =0.995 for gneiss and limestone, respectively. The variation in joint spacing could be attributed to spe- cific energy, bit wear and uniaxial compressive strength which affect drilling condition and performance. Ultimately, as joint spacing gets closer, the drilling velocity increases, drill string will be stable.
文摘目前,我国标准中提出评价冷水机组节能性能的指标主要有性能系数(Coefficient of Performance, COP)、综合部分负荷性能系数(Integrated Part Load Value, IPLV)和非标准部分负荷性能系数(Non-Standard Part Load Value, NPLV)。IPLV/NPLV作为冷水机组部分负荷性能系数性能评价指标有着重要意义,但是在实际使用中也存在着局限。本文借鉴IPLV/NPLV提出了RPLV(Real Part Load Value, RPLV)计算公式确定方法,可以解决IPLV/NPLV使用过程中的局限,包括(1)可以反映特定项目的实际工况;(2)可以反映多台机组在特定运行策略下的运行情况;(3)可以用该指标简单估算冷水机组实际能耗。同时,本文通过实际工程案例对RPLV计算方法进行了实践应用,证明该方法是切实可行的。此外,本文还对RPLV和IPLV/NPLV从负荷区间划分、权重系数、测试工况、能耗估算适用性等方面进行了关键要素对比分析,总结了RPLV的对比IPLV/NPLV的相同与不同之处,为RPLV的实际应用提供参考借鉴。
文摘The reliable assessment of the annual energy demand has become necessary in view of building energy performance certification. Accurate models must be used to simulate the behaviour of HVAC （heating, ventilation and air conditioning） components in real operation, usually characterized by a wide variation of building loads. In this context, this paper deals with the development and validation of an algorithm aimed at the assessment of part load performance of various kinds of controls for vapour compresion based heat pumps and chillers, in particular referring to on-off, inverter-driven and multi-stage vapour compression. The reliability of this algorithm in the calculation of seasonal performances is checked against monitoring of heat pumps and chillers operating under real conditions.
文摘ASHP （air source heat pump） water heater is a renewable and energy efficient device used for sanitary hot water production. The system comprises of a storage tank and heat pump connected by pipes. These major units can either be compact as in the integrated model or split as in the retro-fit model. In this research, the analysis of energy losses was performed using SIRAC （the Southern African refrigeration and air conditioning） residential split type heat pump of 1.2 kW input power to retrofit a 200 liter high pressure kwikhot storage tank without hot water being drawn off for the entire monitoring period. Likewise to experimentally determine the losses DAS （data acquisition system） was designed and built to measure Ta （ambient temperature; RH-relative humidity）, RH, To （ASHP outlet water temperature）, Ti （ASHP inlet water temperature） and Vh. （volume of water heated by ASHP unit）.The results showed that the heat energy gain to compensate standby losses could range from 1.8 kWh to 2.1 kWh with the corresponding electrical energy used by ASHP water heater ranging from 0.55 kWh to 0.66 kWh. The standby losses depend primarily on the Vh, the Ta and the RH while the influence of （To - Ti） is secondary. The results can be of valuable interest to manufacturer of retrofit ASHP unit for hot water production when matching the electrical energy required to compensate for the standby losses.
