Solar thermal heat engines for water pumping: An update
ABSTRACT Solar thermal-driven heat engines for water pumping have been previously reviewed for some authors in the past century. However, some devices have not been treated as metal hydride-based systems or the pumping subsystems of solar thermal-driven reverse osmosis desalination systems. Following the typical classification given in the previous literature, in this work an update of the solar heat engines for water pumping based in thermodynamic methods (conventional and unconventional) is presented. Besides small remarks about systems previously quoted by other authors, new designs found in the literature are described. In general, the main characteristics of these systems is their low efficiency, low power output and, in the case of unconventional designs, its simplicity. This work in conjunction with previous review papers make up reference point for the knowledge of the use of solar thermal energy for liquid pumping purpose.
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ABSTRACT: Conceptual design of a new type solar-powered water pump (SPWP) integrated into flat plate solar collector (FPC) has been carried out. SPWP represents simple heat engine-membrane pump operating through alternating of processes of evaporation and condensation in its working chamber. It should provide circulation of water using part of absorbed by FPC heat and returning it finally to the same heat carrier. Two basic versions of structural layout of FPC have been considered: the first -with flow-through absorber (with circulation of water through riser pipes welded to absorbing plate) and the second – with absorber with gravity-assisted heat pipes (GAHPs). In terms of efficient operation important role of proper organization of boiling heat transfer on downward-facing heating surface of working chamber has been revealed. Thermo-hydrodynamic peculiarities of this process are considered. The results of preliminary experimental study of boiling heat transfer on downward-facing heating surface are presented.
Conference Paper: Simulation of traveling-wave tube cold-test characteristics using MAFIA[Show abstract] [Hide abstract]
ABSTRACT: The three-dimensional simulation code MAFIA4.0 was used to compute the cold-test parameters i.e. frequency-phase dispersion and the electron beam interaction impedance on the axis. The modeling code has high accuracy and will reduce TWT development time and cost. The quasi-periodic boundary condition can be used in MAFIA4.0 to calculate the eigen-frequency for each cavity's phase shift. MAFIA was used to duplicate the perturbation experiment by simulating the CCTWT circuit cold test with a cylindrical dielectric rod. The interaction impedance can be derived from the difference between the eigen-frequency of the perturbed and that of unperturbed for the same setting phase shift. The on-axis interaction impedance also can be calculated directly using MAFIA by applying the quasi-periodic boundary condition. Excellent agreement between the experimental data and the simulation results was obtainedInfrared and Millimeter Waves, 2000. Conference Digest. 2000 25th International Conference on; 02/2000
Conference Paper: A sensitive cell neuron model based on chaos[Show abstract] [Hide abstract]
ABSTRACT: The research in the high sensitivity of the biological sensorium has been the blank in the work of NN (neural network). According to the analyzing results of chaotic theory, the chaotic system has an extremely high sensitivity and resolving power. Based on the application of chaotic theory to measuring, this paper proposes a concept of the sensitive chaotic cell neuron (SCCN) and a mathematical model for SCCN. Like the biological sensorium, the SCCN can get a high sensitivity and resolving power to feeble signals. The simulation results show the high sensitivity of SCCN to the feeble signalsSignal Processing Proceedings, 2000. WCCC-ICSP 2000. 5th International Conference on; 02/2000