The main components of thermophotovoltaic (TPV) devices are the primary lens (or mirror), the absorber, the PV cell, and a photon recuperator system. A theory integrating all these components is used in this paper to analyse a particular type of TPV device (plane disk absorber and PV cell). The TPV efficiency is maximized by using three optimization parameters, namely absorber, PV cell temperatures, and cell voltage. Almost ideal operation conditions are envisaged and upper bounds are obtained for the TPV efficiency. They are strongly dependent on PV cell bandgap and radiation concentration. Preliminary results suggest the existence of an optimum solar radiation concentration ratio. The improvement in thermal design quality allows the usage of PV cells based on wide bandgap semiconductors. 相似文献
The effect of pressure on combustion and heat transfer is analyzed. The research is based on the basic combustion and heat
transfer theorem. A correction for the heat calculation method for pressurized furnace is made on the basis of the normal
pressure case. The correction takes the effect of pressurizing into account. The results show that the correction is reasonable
and the method is applicable to combustion and heat transfer of the marine supercharged boiler. 相似文献
In this paper, we propose a novel distributed robust fault detection and identification (RFDI) scheme for a class of nonlinear systems. Firstly, a detection and identification estimator—robust fault tracking approximator (RFTA) is designed for online health monitoring. A novel feature of the RFTA is that it can simultaneously detect and accurately identify the shape and magnitude of the fault and disturbance. Moreover, it takes less online training time compared with the traditional neural network based fault diagnosis schemes. For some distributed systems, a network of distributed estimators is constructed where the RFTA is embedded into each estimator. Then we use consensus filter to filter the outputs of each estimator. One of the most important merits of the consensus filter is that its outputs can dramatically improve the accuracy of fault detection and identification. Next, the stability of the distributed RFDI scheme is rigorously investigated. Finally, two numerical examples are given to illustrate the feasibility and effectiveness of the proposed approach. 相似文献
Critical heat fluxes (CHFs) were measured for two types of rectangular ducts containing horizontal flat plate heaters. One has the flat plate heater of 6 mm wide and 20 mm long located on the inner lower wall at 50 mm from the inlet. The other duct has two horizontal flat plates of 6 mm wide and 20 mm long on inner upper and lower walls at 50 mm from the inlet. The equation of CHF for the forced convection containing a new nondimensional-parameter m introduced in order to calculate cross-sectionally averaged liquid temperature at the center of the duct was derived based on two fluid model, ordinary convection theorem and experimental results. It was confirmed that this correlation can describe not only the author's data on the duct but also other worker's data for channels with different shapes and sizes. 相似文献
The difference in the turbulent diffusion between the active (heat) and passive (mass) scalars in a thermally stably stratified medium is investigated. The axisymmetric problem is treated on the formation of a turbulent circulation flow above a heated disk and on the turbulent diffusion of a passive scalar (impurity) from a continuous surface source in a stably stratified medium. The results indicate that the thermal stratification causes appreciable differences in the coefficients of turbulent transfer between the active (heat) and passive (mass) scalars. This means that the assumption of the identity of the coefficient of turbulent diffusion of heat and mass, employed in conventional models of turbulence, produces significant errors in estimating the heat and mass transfer in a thermally stably stratified medium. 相似文献
1. 1. System design optimization and validation for single-speed heat pump by S.K. Fischer and C.K. Rice, Oak Ridge National Laboratories.
2. 2. Analysis of on/off cycling for an air-to-air heat pump operating in the heating mode by W.A. Miller, Oak Ridge National Laboratories.
3. 3. Field measured cycling, frosting and defrosting losses for a high efficiency air source heat pump by V.D. Baxter and J.C. Moyers, Oak Ridge National Laboratories.
4. 4. Design and available energy analysis of a heating-only residential heat pump for the Western Pacific Northwest by D.E. Elger, C.M. Reistad and S. Lang, Oregon State University.
5. 5. A study of heat pump service life by Nance C. Lovvorn, Alabama Power Company and Carl C. Hiller, Electric Power Research.
Résumé
1. 1. Optimisation de la conception des systèmes et application à la pompe à chaleur à une seule vitesse;
2. 2. analyse du cycle par tout ou rien d'une pompe à chaleur air-air fonctionnant en mode de chauffage;
3. 3. pertes en fonctionnement cyclique, par givrage et dégivrage mesurées sur place pour une pompe à chaleur de grand rendement dont la source est l'air;
4. 4. conception et analyse de l'énergie disponible d'une pompe à chaleur uniquement pour le chauffage de locaux résidentiels sur la côte du Pacifique nord-ouest occidental;
5. 5. étude de la durée de vie d'une pompe à chaleur.
Les noms et les addresses des auteurs se trouvent dans le sommaire anglais. 相似文献