[en] The contribution under consideration reports on a gamma denitometric measurement of gas concentrations in a vertical heated tube bundle which is flowed around by a fluid. Two measurement positions, two flow rates of the circulating fluid, two subcooling values and eleven heat fluxes were selected for the measurement. The authors of this contribution describe the test facility, measurement methodology, results and their interpretation. The measurement uncertainty is described in detail.

[en] A solar thermal experiment for the thermal performance evaluation of parabolic dish solar cookers suitable for developing countries is presented. Three different solar cooking pots are compared experimentally using three different cooking fluids, namely water, sunflower oil and olive oil. The heating experiments are carried using three identical parabolic dish solar cookers. The mass of the fluid load used in the experimental tests is 2.5 kg, on each test day. The pots that are experimentally tested under Mahikeng, South Africa, conditions are a black stainless steel pot, an aluminium silver pot and a copper pot. The stainless steel black pot shows higher temperatures as compared to the other pots. Higher energy efficiency values are also obtained with the parabolic dish solar cooker using the black stainless steel pot. The absorbing colour of the cooking pot has a more significant effect on the cooking performance than thermal conductivity of the pot. The best heat transfer fluid which obtains higher temperatures and higher cooking efficiencies is sunflower oil. The aluminium silver pot shows the lowest energy efficiencies in almost of all of the experiments. For Mahikeng conditions, the greatest cooking potential in terms of the speed of cooking is shown by the black pot using sunflower oil as the heat transfer fluid. The thermal performance in the cooking experiments is affected by ambient conditions and manual solar tracking. To shorten cooking times, a larger parabolic dish solar cooker can be used. (paper)

[en] The purpose of this study was to investigate the effect of long-term aging on the thermal stability and chemical structure of seven different ILs so as to explore their suitability for use as a heat transfer fluid. This was accomplished by heating the ILs for 15 weeks at 200 °C in an oxidizing environment and performing subsequent analyses on the aged chemicals

[en] The Korea Atomic Energy Research Institute (KAERI) has developed key technologies in preparation of the 'nuclear hydrogen demonstration and development plant' since 2006. In particular, this paper focuses on the experimental research related to high temperature gas loops and a passive cooling test facility. A nitrogen gas loop was constructed in 2007. The design features and test scope are explained using some results obtained from the validation test for the design concept of a process heat exchanger. In the next step, a helium experimental loop was introduced, which was built for verifying bench-scale prototypes of key components in a very high temperature gas-cooled reactor (VHTR). Another test facility for verifying the passive cooling capability of VHTR was designed at the 1/4 scale and the construction started in 2013. The design features and related experimental studies are described in detail. (author)

[en] The work presented here concerns the measurement of heat transfer in a cryogenic tank with several configurations. The experimental test incorporates the conductive heat in the neck, the convection heat transfers between the inner wall of the neck and the ascending vapor resulting from boiling, and the radiation heat transfers between the external envelope and the tank through a vacuum of 10^-8 mm Hg. An experimental prototype was produced in collaboration with the nuclear center of Orsay in France according to a didactic design, which takes into account the Wexler effect and the importance of the radiation compared to the conduction-convection heat transfer. The addition of a screen radiative ventilated with variable position on the neck (which can effectively replace several tens of floating screens), in order to find the optimal position, which minimizes the radiation flux, is presented in this paper

[en] The interface between the Next Generation Nuclear Plant (NGNP) and the hydrogen-generating process plant will contain an intermediate loop that will transport heat from the NGNP to the process plant. Seven possible configurations for the NGNP primary coolant system and the intermediate heat transport loop were identified. Both helium and liquid salts are being considered as the working fluid in the intermediate heat transport loop. A method was developed to perform thermal-hydraulic evaluations of the different configurations and coolants. The evaluations will determine which configurations and coolants are the most promising from a thermal-hydraulic point of view and which, if any, do not appear to be feasible at the current time. Results of the evaluations will be presented in a subsequent report

[en] Compared to the pure refrigerants, the zeotropic refrigerant mixtures have the obvious temperature glide during phase change. Therefore, the Lorenz cycle can be approached with this special attribute. By analysing the heat transfer in the counter flow heat exchanger, a new evaluation method for zeotropic refrigerant mixtures based on the variance of the temperature difference between the refrigerant and heat transfer fluid (HTF) is proposed in this paper. For approaching to the Lorenz cycle and perfect glide matching, the zeotropic mixture which has smaller variance in the heat exchanger should be chosen in the refrigeration cycle. The variance of temperature difference is affected by two factors which are the temperature difference between the inlet and outlet of HTF and the linear relationship between the refrigerant temperature and enthalpy, respectively. The smallest variance of the zeotropic refrigerant can be obtained by setting the temperature difference of HTF to be the optimal temperature difference.

[en] The thermal conductivity of traditional heat transfer fluids is inherently low. Metals or metal oxide in ultra-fine form have orders of magnitudes higher thermal conductivity of those of fluids. So it is a need to understand the fundamental behavior of the metals or metal oxides nanoparticles in base fluids. ZnO is a semiconductor but has a wide range of application. In this study the thermal conductivity and viscosity will be discussed in details with experimental and theoretical models. The application of ZnO based nanofluids will be very much useful in nuclear fusion

[en] The advanced thermal characteristics of nanomaterials allow better heat transfer efficiency in engineering, industrial and technological processes. In this report, the outcome of a comparative analysis between the dynamics of blood carrying Cu nanoparticles and blood carrying single-walled carbon nanotubes (SWCNTs) due to the stretching and rotation of two disks at various levels of rotation, stretching, power-law index and heat source/sink is presented. By using appropriate similarity variables, the leading partial differential equations (PDEs) are altered into one-dimensional equations (ODEs). The resulting ODEs are handled using the shooting method. The impact of governing parameters on the boundary layer profiles is analysed graphically. Fluid velocity gets enhanced in three dimensions during the rotation of the disk, but they predict different behaviours for the stretching parameters of the upper and lower disks. The temperature decays for power-law index, rotation and stretching parameters. Also, the rates of heat transfer are more extensive for shear-thinning. Finally, the effects of the Cu–blood(blood) nanofluid are dominant over the base fluid (blood) and SWCNTs–blood nanofluid. (author)

[en] The heat transfer augmentation in parabolic trough concentrator is gaining importance now a days as it makes the system compact and efficient. Out of various techniques, use of twisted tape inserts is popular due to easy implementation as well as substantial enhancement in system performance. Most of the studies in this field pertaining to experimental/computational analysis with respect to both outdoor and indoor set ups. The rise in convective coefficient of heat transfer fluid due to insert has been studied by many researchers. But such studies are based on uniform heat flux or out-field non-uniform based which is under uncontrollable environment. Hence in the present study, Nusselt number correlations for plain absorber and absorber with twisted tape (y=3.48, 5.42 and 7.36) are developed under the realistic condition of solar concentration with controlled environment. The parity plot shows the maximum deviation of 20% which in turn indicates better quality of fit. (paper)