The Experts below are selected from a list of 9591 Experts worldwide ranked by ideXlab platform
William Dhaeseleer - One of the best experts on this subject based on the ideXlab platform.
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comparison of shell and tube with plate Heat Exchangers for the use in low temperature organic rankine cycles
Energy Conversion and Management, 2014Co-Authors: Daniel Walraven, Ben Laenen, William DhaeseleerAbstract:Organic Rankine cycles (ORCs) can be used for electricity production from low-temperature Heat sources. These ORCs are often designed based on experience, but this experience will not always lead to the most optimal configuration. The ultimate goal is to design ORCs by performing a system optimization. In such an optimization, the configuration of the components and the cycle parameters (temperatures, pressures, mass flow rate) are optimized together to obtain the optimal configuration of power plant and components. In this paper, the configuration of plate Heat Exchangers or shell-and-tube Heat Exchangers is optimized together with the cycle configuration. In this way every Heat Exchanger has the optimum allocation of Heat Exchanger Surface, pressure drop and pinch-point-temperature difference for the given boundary conditions. ORCs with plate Heat Exchangers perform mostly better than ORCs with shell-and-tube Heat Exchangers, but one disadvantage of plate Heat Exchangers is that the geometry of both sides is the same, which can result in an inefficient Heat Exchanger. It is also shown that especially the cooling-fluid inlet temperature and mass flow have a strong influence on the performance of the power plant.
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optimum configuration of shell and tube Heat Exchangers for the use in low temperature organic rankine cycles
Energy Conversion and Management, 2014Co-Authors: Daniel Walraven, Ben Laenen, William DhaeseleerAbstract:Abstract In this paper, a first step towards a system optimization of organic Rankine cycles (ORCs) is taken by optimizing the cycle parameters together with the configuration of shell-and-tube Heat Exchangers. In this way every Heat Exchanger has the optimum allocation of Heat-Exchanger Surface, pressure drop and pinch-point-temperature difference for the given boundary conditions. Different tube configurations are investigated in this paper. It is concluded that the 30°-tube configurations should be used for the single-phase Heat Exchangers and the 60°-tube configuration for the two-phase Heat Exchangers. The performance of subcritical cycles can be strongly improved by adding a second pressure level. Recuperated cycles are only useful when the temperature of the Heat source after the ORC should be relatively high.
Ben Laenen - One of the best experts on this subject based on the ideXlab platform.
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comparison of shell and tube with plate Heat Exchangers for the use in low temperature organic rankine cycles
Energy Conversion and Management, 2014Co-Authors: Daniel Walraven, Ben Laenen, William DhaeseleerAbstract:Organic Rankine cycles (ORCs) can be used for electricity production from low-temperature Heat sources. These ORCs are often designed based on experience, but this experience will not always lead to the most optimal configuration. The ultimate goal is to design ORCs by performing a system optimization. In such an optimization, the configuration of the components and the cycle parameters (temperatures, pressures, mass flow rate) are optimized together to obtain the optimal configuration of power plant and components. In this paper, the configuration of plate Heat Exchangers or shell-and-tube Heat Exchangers is optimized together with the cycle configuration. In this way every Heat Exchanger has the optimum allocation of Heat Exchanger Surface, pressure drop and pinch-point-temperature difference for the given boundary conditions. ORCs with plate Heat Exchangers perform mostly better than ORCs with shell-and-tube Heat Exchangers, but one disadvantage of plate Heat Exchangers is that the geometry of both sides is the same, which can result in an inefficient Heat Exchanger. It is also shown that especially the cooling-fluid inlet temperature and mass flow have a strong influence on the performance of the power plant.
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optimum configuration of shell and tube Heat Exchangers for the use in low temperature organic rankine cycles
Energy Conversion and Management, 2014Co-Authors: Daniel Walraven, Ben Laenen, William DhaeseleerAbstract:Abstract In this paper, a first step towards a system optimization of organic Rankine cycles (ORCs) is taken by optimizing the cycle parameters together with the configuration of shell-and-tube Heat Exchangers. In this way every Heat Exchanger has the optimum allocation of Heat-Exchanger Surface, pressure drop and pinch-point-temperature difference for the given boundary conditions. Different tube configurations are investigated in this paper. It is concluded that the 30°-tube configurations should be used for the single-phase Heat Exchangers and the 60°-tube configuration for the two-phase Heat Exchangers. The performance of subcritical cycles can be strongly improved by adding a second pressure level. Recuperated cycles are only useful when the temperature of the Heat source after the ORC should be relatively high.
Daniel Walraven - One of the best experts on this subject based on the ideXlab platform.
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comparison of shell and tube with plate Heat Exchangers for the use in low temperature organic rankine cycles
Energy Conversion and Management, 2014Co-Authors: Daniel Walraven, Ben Laenen, William DhaeseleerAbstract:Organic Rankine cycles (ORCs) can be used for electricity production from low-temperature Heat sources. These ORCs are often designed based on experience, but this experience will not always lead to the most optimal configuration. The ultimate goal is to design ORCs by performing a system optimization. In such an optimization, the configuration of the components and the cycle parameters (temperatures, pressures, mass flow rate) are optimized together to obtain the optimal configuration of power plant and components. In this paper, the configuration of plate Heat Exchangers or shell-and-tube Heat Exchangers is optimized together with the cycle configuration. In this way every Heat Exchanger has the optimum allocation of Heat Exchanger Surface, pressure drop and pinch-point-temperature difference for the given boundary conditions. ORCs with plate Heat Exchangers perform mostly better than ORCs with shell-and-tube Heat Exchangers, but one disadvantage of plate Heat Exchangers is that the geometry of both sides is the same, which can result in an inefficient Heat Exchanger. It is also shown that especially the cooling-fluid inlet temperature and mass flow have a strong influence on the performance of the power plant.
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optimum configuration of shell and tube Heat Exchangers for the use in low temperature organic rankine cycles
Energy Conversion and Management, 2014Co-Authors: Daniel Walraven, Ben Laenen, William DhaeseleerAbstract:Abstract In this paper, a first step towards a system optimization of organic Rankine cycles (ORCs) is taken by optimizing the cycle parameters together with the configuration of shell-and-tube Heat Exchangers. In this way every Heat Exchanger has the optimum allocation of Heat-Exchanger Surface, pressure drop and pinch-point-temperature difference for the given boundary conditions. Different tube configurations are investigated in this paper. It is concluded that the 30°-tube configurations should be used for the single-phase Heat Exchangers and the 60°-tube configuration for the two-phase Heat Exchangers. The performance of subcritical cycles can be strongly improved by adding a second pressure level. Recuperated cycles are only useful when the temperature of the Heat source after the ORC should be relatively high.
S. N. Kazi - One of the best experts on this subject based on the ideXlab platform.
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retardation of Heat Exchanger Surfaces mineral fouling by water based diethylenetriamine pentaacetate treated cnt nanofluids
Applied Thermal Engineering, 2017Co-Authors: K H Teng, A I Alshammaa, Ahmad Amiri, S. N. Kazi, M A Bakar, B T Chew, A ShawAbstract:Abstract Mineral scale deposition on Heat exchanging Surfaces increases the thermal resistance and reduces the operating service life. The effect is usually intensified at higher temperatures due to the inverse temperature solubility characteristics of some minerals in the cooling water. Scale formation build up when dissolved salt crystallize from solution onto the Heated Surface, forming an adherent deposit. It is very important for Heat transfer applications to cope with the fouling problems in industry. In this present study, a set of fouling experiments was conducted to evaluate the mitigation of calcium carbonate scaling by applying DTPA-treated MWCNT-based water nanofluids on Heat Exchanger Surfaces. Investigation of additive DTPA-treated MWCNT-based water nanofluids (benign to the environment) on fouling rate of deposition was performed. 300 mg L −1 of artificially-hardened calcium carbonate solution was prepared as a fouling solution for deposit analysis. Assessment of the deposition of calcium carbonate on the Heat Exchanger Surface with respect to the inhibition of crystal growth was conducted by Scanning Electron Microscope (SEM). The results showed that the formation of calcium carbonate crystals can be retarded significantly by adding MWCNT-DTPA additives as inhibition in the solution.
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study of mineral fouling mitigation on Heat Exchanger Surface
Desalination, 2015Co-Authors: S. N. Kazi, K H Teng, M S Zakaria, Emad Sadeghinezhad, M A BakarAbstract:Abstract Investigation on fouling behaviour of calcium carbonate on Heat Exchanger Surfaces as well as mitigation of fouling are presented in this paper. By varying parameters such as concentration of the fouling solution, temperature of the Heating Surface, type of materials and use of additives, the fouling rate on the test specimens were observed. A set of experiments were performed by using calcium carbonate solution. Fouling rate, fouling resistances and the rate of Heat transfers were determined for different Heat Exchanger material Surfaces. Fouling resistance is enhanced by the thermal conductivity and temperature of the Heat exchanging Surfaces and also by the concentration of the foulant in the solution. The addition of gum arabic additive (benign to the environment) to the solution retarded the rate of deposition. The results of these investigations could be design aid for economic and enhancement of Heat Exchanger performance.
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mineral scale formation and mitigation on metals and a polymeric Heat Exchanger Surface
Applied Thermal Engineering, 2010Co-Authors: S. N. Kazi, Geoffrey G Duffy, Xiao ChenAbstract:Abstract An experimental set-up was built to study Heat transfer fouling of different pipe materials used in Heat Exchangers. Fouling mitigation investigations using wood pulp fibres in suspension in the fouling liquid were also performed. The new set-up allows progressive visual observation of fouling with time together with a recorded history under the same solution conditions. On completion, the tube under investigation could be removed to obtain quantitative data on the progressive build up of the deposit as well as the composition of the deposit. The experimental technique involved a pipe test specimen being centrally located in a cylindrical tank concentric with a vertical agitator to give constant and uniform flow conditions near the tube Surface. The investigation of calcium sulphate deposition on four different metal Surfaces (copper, aluminium, brass and stainless steel SS 316 respectively) and a polycarbonate Surface reveals that the fouling increases with time but at a decreasing rate. The deposition on a metal Surface can be seen to increase with increasing thermal conductivity and decreasing total Surface energy over the range of experiments. Low Surface energy material such as polycarbonate causes less attraction to the floating crystals and receives less deposition in comparison to the SS Surface. Bleached Kraft softwood fibres at various concentrations were added to the solution to examine their effects on fouling. The results indicate that fouling is reduced as fibre concentration increases. It was also found that the fouling on stainless steel, brass and copper Surfaces were all retarded in presence of fibre in the solution.
Daniele Fiaschi - One of the best experts on this subject based on the ideXlab platform.
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thermo economic assessment of a micro chp system fuelled by geothermal and solar energy
Energy, 2013Co-Authors: Duccio Tempesti, Daniele FiaschiAbstract:A micro combined Heat and power (CHP) plant operating through an Organic Rankine Cycle (ORC) using renewable energy is analysed. The reference system is designed to produce 50 kWe. The Heat sources of the system are geothermal energy at low temperature (80–100 °C) and solar energy. The system uses a solar field composed only by evacuated solar collectors, and work is produced by a single turbine. Different working fluids (e.g. R134a, R236fa, R245fa) are considered in the analysis. The aim of this paper is to assess the cost of the proposed CHP plant and to determine the most convenient working fluid through a thermo-economic analysis. The system is sized in base of the weather data of a city in the centre of Italy in three different months (January, March, July), and the main characteristics of the system (i.e. Heat Exchanger Surface, solar collector area) are presented. The results of the thermo-economic analysis show that R245fa allows the lowest price of electricity production and the lowest overall cost of the CHP plant.
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thermodynamic analysis of two micro chp systems operating with geothermal and solar energy
Applied Energy, 2012Co-Authors: Duccio Tempesti, Giampaolo Manfrida, Daniele FiaschiAbstract:Micro combined Heat and power (CHP) plants operating through an organic Rankine cycle (ORC) using renewable energy are analyzed. The reference system is designed to produce 50kWe. The Heat sources of the system are geothermal energy at low temperature (80–100°C) and solar energy. Two different system layouts, a single and a double stage arrangement, are presented. The first uses a solar field composed only by evacuated solar collectors, and work is produced by a single turbine. In the double-stage system, a field of evacuated solar collectors Heats the working fluid up to an intermediate temperature. After this first stage, only a part of the working fluid flow rate is Heated in a second solar field, composed of direct-steam parabolic through collectors (PTCs), up to the maximum temperature of the cycle. The mechanical work is then produced in two turbo-expanders arranged in series. For the investigations, different working fluids (e.g. R134a, R236fa, R245fa) are considered. The results of the simulation in terms of efficiencies, Heat and electricity production and the main characteristics of the system (i.e. Heat Exchanger Surface, solar collector area) are presented and discussed.
