Solar radiation offers phenomenal potential for energy conversion with energy densities on the order of 1000W/m2 in locations with regularly clear skies. As always, the difficulty lies in finding a solar-electric conversion technology capable of producing electricity at a competitive cost. The SolarCAT (Solar Compressed Air Turbine) system produces electricity by releasing stored compressed air through a series of turbines with solar dish concentrators providing the required heat for efficient conversion to electricity. To minimize impact on capital cost, high recuperator effectiveness targets are sought but unlike typical fuel-fired micro-turbines, raising the recuperator effectiveness of the solar power system yields a benefit in overall system capital cost. Improving efficiency lowers the size and cost of the largest element of the system, namely the dish. In this study potential techniques for achieving a highly compact heat-transfer media were reviewed. Folded fin, packed beds, micro-tubes, lattice frame structures, metal foams, woven textile, and micro-machining techniques were assessed. Textile structures were selected as an appropriate medium to replace the internal folded fin of the SolarCAT recuperator. The relatively long flow (>150mm) path through the proposed screen wafers requires a model for fully-developed forced convective flow between parallel plates. A mathematical model was developed by integrating the results from the work of several authors in the field of textiles and porous media. #100 mesh sintered screen wafers were brazed between two 0.25mm stainless steel sheets and destructively tested to assess their tensile strength. Although iii optimization of the braze parameters was not completed, it was found that many samples survived exposure to internal pressures in excess of 50MPa. This study found that the use of sintered screen wafers to replace the internal folded fin of the SolarCAT recuperator would have advantages over the current design with respect to both overall recuperator effectiveness, size, and cost. Textile structures can be tailored to have wide range of fluid and heat-transfer properties depending on the application. The manufacturing process is relatively simple and could be cost-effective for high-volume production.

Solar radiation offers phenomenal potential for energy conversion with energy densities on the order of 1000W/m2 in locations with regularly clear skies. As always, the difficulty lies in finding a solar-electric conversion technology capable of producing electricity at a competitive cost. The SolarCAT (Solar Compressed Air Turbine) system produces electricity by releasing stored compressed air through a series of turbines with solar dish concentrators providing the required heat for efficient conversion to electricity. To minimize impact on capital cost, high recuperator effectiveness targets are sought but unlike typical fuel-fired micro-turbines, raising the recuperator effectiveness of the solar power system yields a benefit in overall system capital cost. Improving efficiency lowers the size and cost of the largest element of the system, namely the dish. In this study potential techniques for achieving a highly compact heat-transfer media were reviewed. Folded fin, packed beds, micro-tubes, lattice frame structures, metal foams, woven textile, and micro-machining techniques were assessed. Textile structures were selected as an appropriate medium to replace the internal folded fin of the SolarCAT recuperator. The relatively long flow (>150mm) path through the proposed screen wafers requires a model for fully-developed forced convective flow between parallel plates. A mathematical model was developed by integrating the results from the work of several authors in the field of textiles and porous media. #100 mesh sintered screen wafers were brazed between two 0.25mm stainless steel sheets and destructively tested to assess their tensile strength. Although iii optimization of the braze parameters was not completed, it was found that many samples survived exposure to internal pressures in excess of 50MPa. This study found that the use of sintered screen wafers to replace the internal folded fin of the SolarCAT recuperator would have advantages over the current design with respect to both overall recuperator effectiveness, size, and cost. Textile structures can be tailored to have wide range of fluid and heat-transfer properties depending on the application. The manufacturing process is relatively simple and could be cost-effective for high-volume production.

Solar radiation offers phenomenal potential for energy conversion with energy densities on the order of 1000W/m2 in locations with regularly clear skies. As always, the difficulty lies in finding a solar-electric conversion technology capable of producing electricity at a competitive cost. The SolarCAT (Solar Compressed Air Turbine) system produces electricity by releasing stored compressed air through a series of turbines with solar dish concentrators providing the required heat for efficient conversion to electricity. To minimize impact on capital cost, high recuperator effectiveness targets are sought but unlike typical fuel-fired micro-turbines, raising the recuperator effectiveness of the solar power system yields a benefit in overall system capital cost. Improving efficiency lowers the size and cost of the largest element of the system, namely the dish. In this study potential techniques for achieving a highly compact heat-transfer media were reviewed. Folded fin, packed beds, micro-tubes, lattice frame structures, metal foams, woven textile, and micro-machining techniques were assessed. Textile structures were selected as an appropriate medium to replace the internal folded fin of the SolarCAT recuperator. The relatively long flow (>150mm) path through the proposed screen wafers requires a model for fully-developed forced convective flow between parallel plates. A mathematical model was developed by integrating the results from the work of several authors in the field of textiles and porous media. #100 mesh sintered screen wafers were brazed between two 0.25mm stainless steel sheets and destructively tested to assess their tensile strength. Although iii optimization of the braze parameters was not completed, it was found that many samples survived exposure to internal pressures in excess of 50MPa. This study found that the use of sintered screen wafers to replace the internal folded fin of the SolarCAT recuperator would have advantages over the current design with respect to both overall recuperator effectiveness, size, and cost. Textile structures can be tailored to have wide range of fluid and heat-transfer properties depending on the application. The manufacturing process is relatively simple and could be cost-effective for high-volume production.

Solar radiation offers phenomenal potential for energy conversion with energy densities on the order of 1000W/m2 in locations with regularly clear skies. As always, the difficulty lies in finding a solar-electric conversion technology capable of producing electricity at a competitive cost. The SolarCAT (Solar Compressed Air Turbine) system produces electricity by releasing stored compressed air through a series of turbines with solar dish concentrators providing the required heat for efficient conversion to electricity. To minimize impact on capital cost, high recuperator effectiveness targets are sought but unlike typical fuel-fired micro-turbines, raising the recuperator effectiveness of the solar power system yields a benefit in overall system capital cost. Improving efficiency lowers the size and cost of the largest element of the system, namely the dish. In this study potential techniques for achieving a highly compact heat-transfer media were reviewed. Folded fin, packed beds, micro-tubes, lattice frame structures, metal foams, woven textile, and micro-machining techniques were assessed. Textile structures were selected as an appropriate medium to replace the internal folded fin of the SolarCAT recuperator. The relatively long flow (>150mm) path through the proposed screen wafers requires a model for fully-developed forced convective flow between parallel plates. A mathematical model was developed by integrating the results from the work of several authors in the field of textiles and porous media. #100 mesh sintered screen wafers were brazed between two 0.25mm stainless steel sheets and destructively tested to assess their tensile strength. Although iii optimization of the braze parameters was not completed, it was found that many samples survived exposure to internal pressures in excess of 50MPa. This study found that the use of sintered screen wafers to replace the internal folded fin of the SolarCAT recuperator would have advantages over the current design with respect to both overall recuperator effectiveness, size, and cost. Textile structures can be tailored to have wide range of fluid and heat-transfer properties depending on the application. The manufacturing process is relatively simple and could be cost-effective for high-volume production.

A substantial raise in recuperator effectiveness has been established in the past by improving the fabricating and joining configurations regarding the manufacturing of compact recuperators. Further advancement of state-of-the-art recuperators requires providing for increased temperatures and pressures. 1bis can only be achieved by incorporating high temperature materials into the recuperator design. Although many high temperature materials have been identified in past research, less of these can be utilized in new concepts due to difficulties regarding fabricating and joining. However recently, in an independent study, a tungsten-copper alloy was identified through detailed material selection methods as a suitable material for high temperature applications. The validity of tungsten-copper regarding fabricating and joining, to establish a leak tight structure still needs to be demonstrated. The aim of the study is to carry out a comprehensive review of existing recuperator technologies and design methodologies as well as to investigate the manufacturability of tungsten-copper for use in a recuperator design of limited size. More specifically, the objectives entail the following: (1) The comprehensive review of existing recuperator technologies and recuperator design methodologies, (2) The design and fabrication of a recuperator of limited size using tungsten-copper as a heat transfer material and (3) The determination of the feasibility of fabrication of the design and the applicability of the selected W -eu alloy in the design. The fabrication technique that is presented in the design entailed the use of 2.Irm tungsten carbide drill bits to machine the correct recuperator profile, while the recuperator unit was joined by utilizing a mechanical fastening system. Although diffusion bonding was initially identified as the ideal joining technique for the recuperator of this research, restrictions and limitations relating to the use of diffusion bonding has lead to the identification of a fastening system as the technique used. Evaluation of the fabricated recuperator revealed that several factors were outside the initially specified values, inter alia the flatness tolerance of recuperator plate geometries and machined slots precision. These factors contributed to a leaJdng recuperator structure when tested. The most likely contributing factors for the latter relate to non-conforming tolerances achieved in the fabricated design, residual stresses induced by the machining process as well as design issues relating to the recuperator plate geometries. The design and fabrication of a recuperator of limited size using tungsten-copper as a heat transfer material, requires re-evaluation. Similar work will ensure a design of a high quality when provision is made for advanced surface fmishing of machined parts (notably the recuperator plate geometries), slight modifications to the design as well as stress relieving of machined components for the purpose of eliminating any residual stresses thatJnight be present. / Thesis (M.Ing. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2009.

A substantial raise in recuperator effectiveness has been established in the past by improving the fabricating and joining configurations regarding the manufacturing of compact recuperators. Further advancement of state-of-the-art recuperators requires providing for increased temperatures and pressures. 1bis can only be achieved by incorporating high temperature materials into the recuperator design. Although many high temperature materials have been identified in past research, less of these can be utilized in new concepts due to difficulties regarding fabricating and joining. However recently, in an independent study, a tungsten-copper alloy was identified through detailed material selection methods as a suitable material for high temperature applications. The validity of tungsten-copper regarding fabricating and joining, to establish a leak tight structure still needs to be demonstrated. The aim of the study is to carry out a comprehensive review of existing recuperator technologies and design methodologies as well as to investigate the manufacturability of tungsten-copper for use in a recuperator design of limited size. More specifically, the objectives entail the following: (1) The comprehensive review of existing recuperator technologies and recuperator design methodologies, (2) The design and fabrication of a recuperator of limited size using tungsten-copper as a heat transfer material and (3) The determination of the feasibility of fabrication of the design and the applicability of the selected W -eu alloy in the design. The fabrication technique that is presented in the design entailed the use of 2.Irm tungsten carbide drill bits to machine the correct recuperator profile, while the recuperator unit was joined by utilizing a mechanical fastening system. Although diffusion bonding was initially identified as the ideal joining technique for the recuperator of this research, restrictions and limitations relating to the use of diffusion bonding has lead to the identification of a fastening system as the technique used. Evaluation of the fabricated recuperator revealed that several factors were outside the initially specified values, inter alia the flatness tolerance of recuperator plate geometries and machined slots precision. These factors contributed to a leaJdng recuperator structure when tested. The most likely contributing factors for the latter relate to non-conforming tolerances achieved in the fabricated design, residual stresses induced by the machining process as well as design issues relating to the recuperator plate geometries. The design and fabrication of a recuperator of limited size using tungsten-copper as a heat transfer material, requires re-evaluation. Similar work will ensure a design of a high quality when provision is made for advanced surface fmishing of machined parts (notably the recuperator plate geometries), slight modifications to the design as well as stress relieving of machined components for the purpose of eliminating any residual stresses thatJnight be present. / Thesis (M.Ing. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2009.

Diploma thesis deals with the gas turbine closed cycle. The first part concerns the maximum of theoretical efficiency and practical excutable efficiency for the cycles without regeneration, cycles with regeneration and cycles with regeneration with split compression. The second part concerns the optimalization of the recuperator towards the speed of gas flow in the pipes of the recuperator. The third part includes weight and size design of two kinds of recuperators for different levels of regeneration.

Šiuo metu populiariausias konservavimo būdas yra džiovinimas. Džiovinimas – tai technologinis procesas, kurio metu yra pašalinama iš produkto drėgmė, tokiu būdu prailginamas produkto tinkamumo laikas, tuo pačiu išlaikomos arba pagerinamos medžiagų savybės. Džiovinimo metu svarbiausia išlaikyti kokybę, kad džiovinamoje medžiagoje nepakistų pagrindinės medžiagų savybės. Ekstrudavimo procesas suintensyvina kombinuotųjų pašarų džiovinimo procesą. Magistrantūros darbo tikslas – ištirti ekstruduotų kombinuotų pašarų šunims džiovinimo procesą konvejerinėje džiovykloje. Atlikus informacijos šaltinių apžvalgą yra išanalizuotas džiovinimo procesas,džiovinimo būdai, džiovinimo proceso teoriniai pagrindai, šilumos rekuperatorių panaudojimo studija ir kombinuotų pašarų šunims procesas. Ekstruduotieji kombinuotieji pašarai konservuojami išgarinant perteklinę drėgmę konvejerinėje džiovykloje, sumažinant drėgnumą nuo 19,60 iki 8,51 %, kuris atitinka standarto reikalavimus. Džiovinant pašarus konvejerinėje džiovykloje buvo sunaudota 14000 kJ/kgvandens šilumos vienam kilogramui drėgmės išgarinti. Šilumos kiekis reikalingas džiovinimo procesui 654,48 kW. Nustatyta, kad rekuperatoriaus naudingumo koeficientai yra 72%. Šilumos kiekis reikalingas džiovinimo procesui 654,48 kW. Rekuperatorimi konpensuojamos grąžinamos šilumos kiekis yra 471,50 kW. / Currently drying is the most popular conservation method. Drying is a technological process, which removes moisture from the product, in this way the shelf life of the product is extended, at the same time the properties of materials are maintained or upgraded. It is important to maintain the quality in the process of drying in order to avoid unwanted changes of main characteristics of the drying material. The aim of master thesis is to explore drying process in conveyor dryer for the extruded combined feed for dogs. The analysis of the material data was performed specific attention paying to the process of drying, the methods of drying, theoretical background of drying, the study of the heat recuperator use and the process of combined feed for dogs. Extruded combined feed in conveyor dryer is preserved by evaporating excess moisture, the moisture is reduced from 19,60 to 8,51%, which complies with the requirements of the standard. For the feed drying the amount of heat to evaporate one kilogram of water in the conveyor dryer is 14000 kJ/kgH2O. The quantity of heat needed for the drying process is 654,48 kW. It was established that the efficiency units of recuperator are 72 %. The quantity of heat needed for the drying process is 654,48 kW. Compensated returned heat amount in recuperator is 471,50 kW.

This thesis deals with the high efficiency gas turbine recuperator design and its production methods. First part of the work presents an analysis of basic constructions and materials used for present recuperators. The requirements on the recuperator for a low emission gas turbine power source are then specified and the recuperator is designed according to the available literature sources. The quality of the heat transfer surface is examined by CFD modeling using the commercial CFD code Star-CD. The second part deals with the recuperator manufacturing and experimental validation of the designed recuperator performance. This section describes ways to build the recuperator matrix, technologies available to assemble the recuperator and methodology of measurements. Experimental results are presented including a discussion of the uncertainties of determining individual variables. Finally the engineering equations are found based on the experimental data obtained, that can be employed to design the recuperator.

No description available.