The Experts below are selected from a list of 3756 Experts worldwide ranked by ideXlab platform
Xianjie Sheng - One of the best experts on this subject based on the ideXlab platform.
-
energy saving factors affecting analysis on district heating system with distributed variable frequency speed Pumps
Applied Thermal Engineering, 2017Co-Authors: Xianjie Sheng, Lin DuanmuAbstract:Abstract The distributed variable-frequency speed Pump (DVFSP) district heating system is not only to set Circulating Pump in the heat source, but also to set booster Pumps in the heating pipeline network. All Pumps adopt frequency conversion control. Compared with the traditional centralized power heat supply system, the distributed variable-frequency speed Pump district heating system has more advantages in solving the hydraulic imbalances and improving the energy-saving rate of the heating system. In China the application of distributed variable speed Pumps in the district heating (DH) network has been considered as a technology improvement that has a potential of saving energy, compared to the conventional central Circulating Pump (CCCP) DH system. In order to analyze the factors affecting energy-saving rates and pipe network balance mathematical analytical method is used in this paper. In the conclusion, how to further improve the energy saving rate will be put forward together with the improvements for hydraulic stability balance as a reference of optimized engineering design.
-
energy saving analyses on the reconstruction project in district heating system with distributed variable speed Pumps
Applied Thermal Engineering, 2016Co-Authors: Xianjie ShengAbstract:Abstract Optimization of the district heating (DH) piping network is of vital importance to the economics of the whole DH system. The application of distributed variable frequency speed Pump (DVFSP) in the district heating network has been considered as a technology improvement that has a potential in saving energy compared to the conventional central Circulating Pump (CCCP) district heating system (DHS). Economic frictional factor is a common design parameter used in DH pipe network design. In this paper, the mathematical model of economic frictional factor based on DVFSP DHS is established, and influence factors are analyzed, providing a reference for engineering designs for the system. According to the analysis results, it is studied that the energy efficiency in the DH system with the DVFSP is compared with the one in the DH system with conventional central Circulating Pump (CCCP) using a case based on a district heating network in Dalian, China. The results of the study on the case show that the average electrical energy saved is 49.41% of the one saved by the DH system with conventional central Circulating Pump in the primary network.
-
electricity consumption and economic analyses of district heating system with distributed variable speed Pumps
Energy and Buildings, 2016Co-Authors: Xianjie Sheng, Lin DuanmuAbstract:Abstract The increasing of energy efficiency and decreasing the transportation power consumption of District Heating (DH) systems have been increasingly focused due to the need to save energy. In this paper a new district heating network with distributed variable-frequency speed Pumps (DVFSP) is presented and analyzed. The approach for minimum of the capital costs and energy consumption in a district heating network is presented using a case study based on a district heating network with DVFSP in Dalian, China. The computational tool is a commercial software package, which is used to design and analyze DH networks. Increasing temperature difference between supply and return pipes, the annual total electricity consumption and the equivalent annual cost are reduced. The energy efficiency in the DH system with the DVFSP was compared with the one in the DH system with conventional central Circulating Pump (CCCP). Analysis results show that the average electrical energy saved by the DH system with the DVFSP is 49.41% of the one saved by the DH system with conventional central Circulating Pump. The average Pumps power consumption of heating area per square meter in primary heat supply network is 0.325 kWh/m2.
Franco N C Wong - One of the best experts on this subject based on the ideXlab platform.
-
efficient single photon counting at 1 55 µm by means of frequency upconversion
Optics Letters, 2004Co-Authors: Marius A Albota, Franco N C WongAbstract:We demonstrate efficient single-photon detection at 1.55 microm by means of sum-frequency mixing with a strong Pump at 1.064 microm in periodically poled lithium niobate followed by photon counting in the visible region. This scheme offers significant advantages over existing InGaAs photon counters: continuous-wave operation, higher detection efficiency, higher counting rates, and no afterpulsing. We achieved single-photon upconversion efficiency of 90% at 21.6 W of Circulating power in a resonant Pump cavity with a 400-mW Nd:YAG laser. We observed high background counts at strong Circulating Pump powers due to efficient upconversion of Pump-induced fluorescence photons.
-
efficient single photon counting at 1 55 microm by means of frequency upconversion
Optics Letters, 2004Co-Authors: Marius A Albota, Franco N C WongAbstract:We demonstrate efficient single-photon detection at 1.55 µm by means of sum-frequency mixing with a strong Pump at 1.064 µm in periodically poled lithium niobate followed by photon counting in the visible region. This scheme offers significant advantages over existing InGaAs photon counters: continuous-wave operation, higher detection efficiency, higher counting rates, and no afterpulsing. We achieved single-photon upconversion efficiency of 90% at 21.6 W of Circulating power in a resonant Pump cavity with a 400-mW Nd:YAG laser. We observed high background counts at strong Circulating Pump powers due to efficient upconversion of Pump-induced fluorescence photons.
Lin Duanmu - One of the best experts on this subject based on the ideXlab platform.
-
energy saving factors affecting analysis on district heating system with distributed variable frequency speed Pumps
Applied Thermal Engineering, 2017Co-Authors: Xianjie Sheng, Lin DuanmuAbstract:Abstract The distributed variable-frequency speed Pump (DVFSP) district heating system is not only to set Circulating Pump in the heat source, but also to set booster Pumps in the heating pipeline network. All Pumps adopt frequency conversion control. Compared with the traditional centralized power heat supply system, the distributed variable-frequency speed Pump district heating system has more advantages in solving the hydraulic imbalances and improving the energy-saving rate of the heating system. In China the application of distributed variable speed Pumps in the district heating (DH) network has been considered as a technology improvement that has a potential of saving energy, compared to the conventional central Circulating Pump (CCCP) DH system. In order to analyze the factors affecting energy-saving rates and pipe network balance mathematical analytical method is used in this paper. In the conclusion, how to further improve the energy saving rate will be put forward together with the improvements for hydraulic stability balance as a reference of optimized engineering design.
-
electricity consumption and economic analyses of district heating system with distributed variable speed Pumps
Energy and Buildings, 2016Co-Authors: Xianjie Sheng, Lin DuanmuAbstract:Abstract The increasing of energy efficiency and decreasing the transportation power consumption of District Heating (DH) systems have been increasingly focused due to the need to save energy. In this paper a new district heating network with distributed variable-frequency speed Pumps (DVFSP) is presented and analyzed. The approach for minimum of the capital costs and energy consumption in a district heating network is presented using a case study based on a district heating network with DVFSP in Dalian, China. The computational tool is a commercial software package, which is used to design and analyze DH networks. Increasing temperature difference between supply and return pipes, the annual total electricity consumption and the equivalent annual cost are reduced. The energy efficiency in the DH system with the DVFSP was compared with the one in the DH system with conventional central Circulating Pump (CCCP). Analysis results show that the average electrical energy saved by the DH system with the DVFSP is 49.41% of the one saved by the DH system with conventional central Circulating Pump. The average Pumps power consumption of heating area per square meter in primary heat supply network is 0.325 kWh/m2.
Hai Wang - One of the best experts on this subject based on the ideXlab platform.
-
enhance hydraulic balance of a district cooling system with multiple jet Pump
Energy Procedia, 2019Co-Authors: Haiying Wang, Hai WangAbstract:Abstract Due to the small temperature difference between the supply and return water in the conventional district cooling system, the flow rates of the chilled water have to be very large to fulfill the buildings’ huge cooling demands. To save the electricity consumptions of the Circulating water, the variable-speed Pumps are commonly applied. However, it may deteriorate the hydraulic balance of the pipe network in most circumstances. The variable flow rates necessitate dynamic hydraulic balance in a pipe network. The conventional approaches, which depend on the throttle valves, can hardly adapt the dynamic regulations. Therefore, a new scheme of applying the jet Pumps is introduced in this study to enhance the hydraulic balance of the district cooling system. The proposed jet Pump has an adjustable jet orifice, which is flexible to adjust the local water mixture ratio. With these jet Pumps installed at the entrances of the buildings, the thermal load conditioning for each building can be performed by adjusting the local jet orifice. Then the chiller plant can operate independently without considering the mutual hydraulic influences of the buildings. Furthermore, the electricity consumption of the Circulating Pump can be saved significantly in the proposed scheme where there are less water flow rates in the main pipelines and lower supply water temperature. The simulation results showed that the dynamic hydraulic balance can be achieved more conveniently by the proposed scheme, in such scenarios as the thermal loads or the hydraulic resistances of the buildings varied a little from time to time. The electricity consumption of the Circulating Pump can also be saved as much as 10-30%.
-
a new hydraulic regulation method on district heating system with distributed variable speed Pumps
Energy Conversion and Management, 2017Co-Authors: Hai Wang, Haiying Wang, Tong ZhuAbstract:Abstract Compared with the hydraulic configuration based on the conventional central Circulating Pump, a district heating system with distributed variable-speed-Pumps configuration can often save 30–50% power consumption on Circulating Pumps with frequency inverters. However, the hydraulic regulations on distributed variable-speed-Pumps configuration could be more complicated than ever while all distributed Pumps need to be adjusted to their designated flow rates. Especially in a multi-source looped structure heating network where the distributed Pumps have strongly coupled and severe non-linear hydraulic connections with each other, it would be rather difficult to maintain the hydraulic balance during the regulations. In this paper, with the help of the advanced automation and information technologies, a new hydraulic regulation method was proposed to achieve on-site hydraulic balance for the district heating systems with distributed variable-speed-Pumps configuration. The proposed method was comprised of a new hydraulic model, which was developed to adapt the distributed variable-speed-Pumps configuration, and a calibration model with genetic algorithm. By carrying out the proposed method step by step, the flow rates of all distributed Pumps can be progressively adjusted to their designated values. A hypothetic district heating system with 2 heat sources and 10 substations was taken as a case study to illustrate the feasibility of the proposed method. Two scenarios were investigated respectively. In Scenario I, the flow rate of one substation varied according to its heat demand and the flow rates of other substations maintained their original values. And in Scenario II, the flow rates of all substations varied synchronously with the same relative rate. The results of the both scenarios indicated that all Pumps could be properly adjusted to their designated flow rates by the proposed method with a high frequency adjustment resolution as 0.001 Hz. In scenario I, compared with the district heating system with distributed variable-speed-Pumps configuration, the power consumption would be 26.6–66.8% less than that of the conventional central Circulating Pump configuration during the 4 rounds of regulations. In scenario II, the energy saving ratio of the district system with distributed variable-speed-Pumps configuration would be 36.1–90.3% less than that of the conventional central Circulating Pump configuration during the 5 rounds of regulations.
Marius A Albota - One of the best experts on this subject based on the ideXlab platform.
-
efficient single photon counting at 1 55 µm by means of frequency upconversion
Optics Letters, 2004Co-Authors: Marius A Albota, Franco N C WongAbstract:We demonstrate efficient single-photon detection at 1.55 microm by means of sum-frequency mixing with a strong Pump at 1.064 microm in periodically poled lithium niobate followed by photon counting in the visible region. This scheme offers significant advantages over existing InGaAs photon counters: continuous-wave operation, higher detection efficiency, higher counting rates, and no afterpulsing. We achieved single-photon upconversion efficiency of 90% at 21.6 W of Circulating power in a resonant Pump cavity with a 400-mW Nd:YAG laser. We observed high background counts at strong Circulating Pump powers due to efficient upconversion of Pump-induced fluorescence photons.
-
efficient single photon counting at 1 55 microm by means of frequency upconversion
Optics Letters, 2004Co-Authors: Marius A Albota, Franco N C WongAbstract:We demonstrate efficient single-photon detection at 1.55 µm by means of sum-frequency mixing with a strong Pump at 1.064 µm in periodically poled lithium niobate followed by photon counting in the visible region. This scheme offers significant advantages over existing InGaAs photon counters: continuous-wave operation, higher detection efficiency, higher counting rates, and no afterpulsing. We achieved single-photon upconversion efficiency of 90% at 21.6 W of Circulating power in a resonant Pump cavity with a 400-mW Nd:YAG laser. We observed high background counts at strong Circulating Pump powers due to efficient upconversion of Pump-induced fluorescence photons.