The Experts below are selected from a list of 204 Experts worldwide ranked by ideXlab platform

Christian Dötsch - One of the best experts on this subject based on the ideXlab platform.

  • Solar driven steam jet ejector chiller
    Applied Thermal Engineering, 2009
    Co-Authors: Clemens Pollerberg, Christian Dötsch
    Abstract:

    Abstract This paper presents a solar driven process to generate Cold Water for air-conditioning by parabolic trough collectors and a steam jet ejector chiller. The only working fluid in the system is Water, which is used as refrigerant and working fluid. The operational behaviour of such a system has been investigated by a small test rig. The investigation shows that the cooling Water Temperature as well as the Cold Water Temperature has a strong influence on the coefficient of performance of a steam jet ejector chiller. The coefficient of performance reaches high values in part load and at good re-cooling conditions, so that the mean efficiency is clearly higher than the nominal efficiency of the system. A first calculation of profitability leads to specific Cold cost of 0.62 €/kWh in Germany and 0.15 €/kWh in Egypt.

  • Solar driven steam jet ejector chiller
    Applied Thermal Engineering, 2009
    Co-Authors: Clemens Pollerberg, Ahmed Hamza H. Ali, Christian Dötsch
    Abstract:

    This paper presents a solar driven process to generate Cold Water for air-conditioning by parabolic trough collectors and a steam jet ejector chiller. The only working fluid in the system is Water, which is used as refrigerant and working fluid. The operational behaviour of such a system has been investigated by a small test rig. The investigation shows that the cooling Water Temperature as well as the Cold Water Temperature has a strong influence on the coefficient of performance of a steam jet ejector chiller. The coefficient of performance reaches high values in part load and at good re-cooling conditions, so that the mean efficiency is clearly higher than the nominal efficiency of the system. A first calculation of profitability leads to specific Cold cost of 0.62 €/kWh in Germany and 0.15 €/kWh in Egypt. © 2008 Elsevier Ltd. All rights reserved.

Clemens Pollerberg - One of the best experts on this subject based on the ideXlab platform.

  • Solar driven steam jet ejector chiller
    Applied Thermal Engineering, 2009
    Co-Authors: Clemens Pollerberg, Christian Dötsch
    Abstract:

    Abstract This paper presents a solar driven process to generate Cold Water for air-conditioning by parabolic trough collectors and a steam jet ejector chiller. The only working fluid in the system is Water, which is used as refrigerant and working fluid. The operational behaviour of such a system has been investigated by a small test rig. The investigation shows that the cooling Water Temperature as well as the Cold Water Temperature has a strong influence on the coefficient of performance of a steam jet ejector chiller. The coefficient of performance reaches high values in part load and at good re-cooling conditions, so that the mean efficiency is clearly higher than the nominal efficiency of the system. A first calculation of profitability leads to specific Cold cost of 0.62 €/kWh in Germany and 0.15 €/kWh in Egypt.

  • Solar driven steam jet ejector chiller
    Applied Thermal Engineering, 2009
    Co-Authors: Clemens Pollerberg, Ahmed Hamza H. Ali, Christian Dötsch
    Abstract:

    This paper presents a solar driven process to generate Cold Water for air-conditioning by parabolic trough collectors and a steam jet ejector chiller. The only working fluid in the system is Water, which is used as refrigerant and working fluid. The operational behaviour of such a system has been investigated by a small test rig. The investigation shows that the cooling Water Temperature as well as the Cold Water Temperature has a strong influence on the coefficient of performance of a steam jet ejector chiller. The coefficient of performance reaches high values in part load and at good re-cooling conditions, so that the mean efficiency is clearly higher than the nominal efficiency of the system. A first calculation of profitability leads to specific Cold cost of 0.62 €/kWh in Germany and 0.15 €/kWh in Egypt. © 2008 Elsevier Ltd. All rights reserved.

Li Zhao - One of the best experts on this subject based on the ideXlab platform.

  • experimental research on the influence of system parameters on the composition shift for zeotropic mixture isobutane pentane in a system occurring phase change
    Energy Conversion and Management, 2016
    Co-Authors: Li Zhao
    Abstract:

    Abstract Zeotropic mixture can improve the performance of the thermodynamic cycle ascribed to the better Temperature match during the heat transfer process with the characteristics of Temperature glide during evaporation and condensing processes. Another characteristic of zeotropic mixture is composition shift. Composition shift means that the circulating composition and charge composition is different and is mainly caused by the two-phase hold-up and different solubility in lubricating oil. The existence of composition shift will affect the design and operation of thermodynamic system. The previous study gave little information about the influence of system parameters on the composition shift in a system occurring phase change. This paper mainly discuss the influence of system parameters on the composition shift for zeotropic mixture in a system occurring phase change as well as the validation of the linear relationship between the circulating composition and the charge composition and the inverse proportion relationship between the circulating composition and the charge mass found based on our previous theory study (Zhao and Bao, 2014). With isobutane and pentane as the research object, the impact of the key system parameters (hot Water Temperature, mass flow rate of hot Water, feed pump frequency, Cold Water Temperature and evaporator length) on composition shift are experimentally carried out. The results show that when the hot Water Temperature, mass flow rate of hot Water and evaporator length increase and Cold Water Temperature decreases, circulating composition will increase. For feed pump frequency, when the outlet of evaporator is in two phase region, and circulating composition will decreased with the increase of feed pump frequency; while the outlet of evaporator is in a state of overheating, circulating composition will increase as the feed pump frequency rises. The linear relationship between the circulating composition and the charge composition and the inverse proportion relationship between the circulating composition and the charge mass are verified by the experiment.

  • Experimental research on the influence of system parameters on the composition shift for zeotropic mixture (isobutane/pentane) in a system occurring phase change
    Energy Conversion and Management, 2016
    Co-Authors: Li Zhao
    Abstract:

    Abstract Zeotropic mixture can improve the performance of the thermodynamic cycle ascribed to the better Temperature match during the heat transfer process with the characteristics of Temperature glide during evaporation and condensing processes. Another characteristic of zeotropic mixture is composition shift. Composition shift means that the circulating composition and charge composition is different and is mainly caused by the two-phase hold-up and different solubility in lubricating oil. The existence of composition shift will affect the design and operation of thermodynamic system. The previous study gave little information about the influence of system parameters on the composition shift in a system occurring phase change. This paper mainly discuss the influence of system parameters on the composition shift for zeotropic mixture in a system occurring phase change as well as the validation of the linear relationship between the circulating composition and the charge composition and the inverse proportion relationship between the circulating composition and the charge mass found based on our previous theory study (Zhao and Bao, 2014). With isobutane and pentane as the research object, the impact of the key system parameters (hot Water Temperature, mass flow rate of hot Water, feed pump frequency, Cold Water Temperature and evaporator length) on composition shift are experimentally carried out. The results show that when the hot Water Temperature, mass flow rate of hot Water and evaporator length increase and Cold Water Temperature decreases, circulating composition will increase. For feed pump frequency, when the outlet of evaporator is in two phase region, and circulating composition will decreased with the increase of feed pump frequency; while the outlet of evaporator is in a state of overheating, circulating composition will increase as the feed pump frequency rises. The linear relationship between the circulating composition and the charge composition and the inverse proportion relationship between the circulating composition and the charge mass are verified by the experiment.

Ahmed Hamza H. Ali - One of the best experts on this subject based on the ideXlab platform.

  • Solar driven steam jet ejector chiller
    Applied Thermal Engineering, 2009
    Co-Authors: Clemens Pollerberg, Ahmed Hamza H. Ali, Christian Dötsch
    Abstract:

    This paper presents a solar driven process to generate Cold Water for air-conditioning by parabolic trough collectors and a steam jet ejector chiller. The only working fluid in the system is Water, which is used as refrigerant and working fluid. The operational behaviour of such a system has been investigated by a small test rig. The investigation shows that the cooling Water Temperature as well as the Cold Water Temperature has a strong influence on the coefficient of performance of a steam jet ejector chiller. The coefficient of performance reaches high values in part load and at good re-cooling conditions, so that the mean efficiency is clearly higher than the nominal efficiency of the system. A first calculation of profitability leads to specific Cold cost of 0.62 €/kWh in Germany and 0.15 €/kWh in Egypt. © 2008 Elsevier Ltd. All rights reserved.

Baoqiang Liao - One of the best experts on this subject based on the ideXlab platform.

  • Reversibility of membrane performance and structure changes caused by extreme Cold Water Temperature and elevated conditioning Water Temperature
    Water Research, 2018
    Co-Authors: Adrianna Tikka, Baoqiang Liao
    Abstract:

    Abstract The effects of extreme Cold Water Temperature, elevated cleaning Water Temperature, cleaning time on membrane performance, and pore size distribution were studied using flat-sheet polyvinylidene fluoride (PVDF) membranes. Extreme Cold Water Temperature led to a decrease in membrane permeability, and membrane pore size shrinkage. The use of periodical warm Water (35 °C) membrane conditioning could almost completely recover the membrane permeability and pore size structure loss caused by extreme Cold Water Temperature, while the use of room Temperature (23±1 °C) conditioning recovered majority of the membrane permeability and structure loss caused by extreme Cold Water Temperature. Changes in membrane performance correlate well with changes in membrane structure. Membranes periodically conditioned in warmer Water Temperature showed a higher permeability than that periodically conditioned at room Temperature from a long-term operation of three months. The results suggest the change in PVDF membrane performance and structure caused by extreme Cold Water Temperature is almost completely reversible after periodical warm Water conditioning, and thus the use of warm Water conditioning and/or chemical cleaning will benefit the recovery of membrane performance and structure change caused by extreme Cold Water Temperature in Cold regions.

  • effect of Cold Water Temperature on membrane structure and properties
    Journal of Membrane Science, 2017
    Co-Authors: Carl Goodwin, Baoqiang Liao
    Abstract:

    Abstract The Temperature dependence of intrinsic hollow fiber (HF) membrane structure and properties (lumen dimension, pore size distribution, porosity, permeability, resistance, dextran rejection, and break strength) were investigated at room Temperature of 21 ± 1 °C and extreme Cold Water Temperature of 0.3 °C in a well-controlled Cold room. No significant changes in membrane structures and properties were observed in three months continuous filtration operation at room Temperature (21 ± 1 °C). A decrease in membrane lumen diameter and membrane permeability and an increase in the intrinsic hydraulic resistance and dextran rejection were observed for membrane operated at the extreme Cold Water Temperature (0.3 °C) in the first few weeks of operation. An increase in operational membrane flux resulted in a more significant changes in membrane structure and properties at 0.3 °C. The results suggest that extreme Cold Water Temperature could alter the intrinsic membrane structure and properties in the first few weeks of operation, the changes in membrane structure were largely reversible under tested conditions, although a significant change (11% increase in resistance) remained. A reduction in operational membrane flux in the Cold season could minimize changes in membrane structure and properties.