... and spacing between the fins, while the heat transfer and fluid flow are directed by natural convection. An inclined rectangular channel similar to the dimensions of a typical solar air heater has been considered. Three different fin configurations, namely, continuous long fins for the whole length...

... are both very important factors for flow friction factors and heat exchanger efficiency in the conversion system. Pumping is needed in water based solar thermal conversion because natural convection of water fluid is relatively weak with low circulation rate and conversion efficiency. In recent years...

..., while it has an unfavorable effect on the second-law efficiency. photovoltaic/thermal (PV/T) collector natural convection first law efficiency second law efficiency fins Thermal and electrical energy greatly affect human life. Since clean energy sources like solar energy do not produce...

... exchanger provided the best heat transfer performance. natural convection thermal storage tanks baffle shroud immersed heat exchanger Solar thermal storage tanks typically are configured to take advantage of stratification to exchange heat by way of natural convection. In the charging...

... and exergy efficiency of the studied system. 27 04 2011 21 09 2011 29 11 2011 29 11 2011 exergy photovoltaic cells solar absorber-convertors photovoltaic/thermal solar collector natural convection glass cover thermal efficiency electrical efficiency exergy...

... number by as much as twentyfold. 24 01 2011 26 08 2011 29 11 2011 29 11 2011 heat exchangers natural convection numerical analysis solar power tanks (containers) thermal energy storage transient analysis water storage thermal stores immersed heat exchanger...

...S. Paitoonsurikarn; K. Lovegrove; G. Hughes; J. Pye In open cavity receivers employed in solar paraboloidal dish applications, natural convection occurs and contributes a significant fraction of energy loss. Its characteristics hence need to be clarified so that it can be effectively minimized...

..., especially in the state close to the critical point. Thus, natural convective flow of the supercritical carbon dioxide can be easily induced by solar heating or water cooling. Such convective flow absorbs and transports heat to water in solar collector tubes. Motivated by the above idea, an experimental...

...Cynthia A. Cruickshank; Stephen J. Harrison This paper presents a simplified test method that was developed to allow preconfigured solar domestic hot water systems that use natural convection/thermosyphon heat exchangers to be characterized. The results of this test method produce performance...

...Yan Su; Jane H. Davidson The transient natural convective thermal/fluid processes during discharge of an inclined rectangular solar storage tank via an immersed heat exchanger are modeled and compared to prior experimental data. The model treats the heat exchanger as a porous medium within...

...Yan Su; Jane H. Davidson A scale analysis of the transient discharge of a fully mixed thermal storage vessel with an immersed single-tube heat exchanger is extended to provide a generalized expression for the transient natural convection Nusselt number for heat exchangers comprising many tubes...

... materials numerical analysis forced convection natural convection heat conduction thermal energy storage Warm and desert climates are characterized by rather high temperatures during the daytime, and in order to provide thermal comfort conditions inside buildings air conditioners are usually...

... of chilled ceiling is not included. Thermal plumes or vertical mixing generated by heating or cooling on the walls are ignored. A two-layer structure will not be destroyed in any case. Wind effect is not combined in this model. Natural convection is assumed on all interior surfaces...

... of the simulated geometry by Liu et al. ( 3 8 10 12 ) is restricted to measurements of transient temperature distribution and average heat transfer. These papers report the first measurements of natural convection heat transfer from a horizontal tube ( 3 8 ) and tube bundles immersed near the top of the ICS...

...W. Liu; J. H. Davidson, Fellow of ASME; F. A. Kulacki, Fellow of ASME Natural convection is measured in an enclosure that represents an integral collector storage system (ICS) with an immersed tube-bundle heat exchanger. Heat transfer coefficients for bundles of 240 tubes contained in a thin...

... cooling natural convection Polymer materials may offer cost savings as substitutes for metal absorber plates in traditional collector systems or as part of all-polymer systems. In fact, flat-plate collectors that use polymeric absorbers are reaching the market in Europe ( 1 ). It is possible...

...T. Taumoefolau; S. Paitoonsurikarn; G. Hughes; K. Lovegrove Natural convection heat loss inevitably occurs in cavity-type receivers in high concentrating solar dishes, downward focusing systems and solar towers. In most applications, it can contribute a significant fraction of total energy loss...

...W. Liu; J. H. Davidson, Fellow of ASME,; F. A. Kulacki, Fellow of ASME, Natural convection heat transfer coefficients for a rectangular array of eight tubes contained in a thin enclosure of aspect ratio 9.3:1 and inclined at 30 deg to the horizontal are measured for a range of transient operating...

...Pai-Chuan Liu The knowledge of steady-state temperature distribution is known a priori for natural convection stability analysis. The present study determines the temperature profiles in an infinite horizontal layer of fluid filled with saturated porous medium confined between two convective...

... collector storage. Experiments are conducted for isothermal and stratified enclosures with both adiabatic and uniform heat flux boundary conditions. Natural convection flow in the enclosure is interpreted from measured water temperature distributions. Formation of an appropriate temperature difference...