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In order to make full use of the advantages of superheated steam (SHS), SHS injection in multi-point injection wells (MPIW) is proposed in this paper. Firstly, a mathematical model comprised of SHS flow model in inner tubing (IT) or long tubing (LT) and annulus, transient heat transfer model in oil layer is established. Secondly, type curves of SHS flow in MPIW is obtained by finite difference method on space and the iteration technique. Then, the effect of injection temperature on distributions of thermophysical properties of SHS in MPIW is discussed in detail. Results show that: (a) When the heat exchange between IT and annulus is taken into consideration. SHS temperature in IT has a decrease while SHS temperature in annulus has an increase. (b) With the help of MPIW, heating effect at both heel and toe points of the horizontal wellbores can be enhanced. (c) While the increase of SHS temperature certainly benefits the formation heating effect through the increase of both SHS temperature and superheat degree, the following decrease of SHS pressure in annulus will lead to the decrease of SHS absorption rate. This paper unravels some intrinsic flow characteristics of SHS in MPIW, which has a significant impact on the optimization of SHS injection parameters and analysis of heat transfer law in MPIW. [ABSTRACT FROM AUTHOR]

The photovoltaic thermal collector can provide thermal and heat power at the same time. In this paper, a photovoltaic/thermal sheet and tube collector has been numerically investigated. The paper focuses on the development of a hybrid solar collector PV/T. This model will be applied to optimize the operation of the PVT collector in the semi-arid climate. A mathematical model has been developed to determine the dynamic behavior of the collector, based on the energy balance of six main components namely a transparent cover, a PV module, a plate absorber, a tube, water in the tube and insulation. It has been validated by comparing the obtained simulation results with experimental results available in literature, where good agreement has been noted. Using our developed model, the heat and electrical power of sheet and tube collector has been analyzed for four typical days of year with the meteorological parameters of Monastir, Tunisia. Furthermore, the effect of solar radiation, the inlet water temperature, the number of glazing covers and the conductive heat transfer coefficient between plate absorber and PV module have been involved to identify their influence on the thermal and electrical efficiencies. The monthly thermal and electrical energies is also evaluated. [ABSTRACT FROM AUTHOR]