A new method has been proposed to estimate top heat losses of vertical flat plate liquid/air collectors with double glazing. Empirical relations have been developed for the temperatures of glass covers, thus facilitating the calculation of individual heat transfer coefficients. The values of individual heat transfer coefficients therefore obtained can be used in the proposed analytical equation for the estimation of the top heat loss coefficient of the vertical collector with double glazing. The analytical equation has been developed for collector tilt angle of 60 to 90 degrees, plate temperature of 323 K to 423 K, absorber coating emittance of 0.1 to 0.95, air gap spacing of 20 mm to 50mm between the plate and inner glass cover, air gap spacing of 20 mm to 50mm between glass covers, wind heat transfer coefficient of 5 W/m2K to 30 W/m2K, and ambient temperature of 263K to 313K. The accuracy of the analytical equation has been validated for the said range of variables in comparison to numerical solutions, and the values of the top heat loss coefficient are found to be within 2.5 percent compared to numerical solutions.

The Method of Discretization in Time (MDT) is a hybrid numerical technique intended to alleviate upfront the computational procedure of timedependent partial differential equations of parabolic type upfront. The MDT engenders a sequence of adjoint second order ordinary differential equations, wherein the space coordinate is the independent variable and time becomes an embedded parameter. Essentially, the adjoint second order ordinary differential equations are considered of “quasistationary” nature. In this work, the MDT is used for the analysis of unsteady heat conduction in regular bodies (large wall, long cylinder and sphere) accounting for nearly constant thermophysical properties, uniform initial temperature and surface heat flux. In engineering applications, the surface heat flux is customarily provided by electrical heating, radiative heating and pool fire heating. It is demonstrated that the approximate, semianalytical temperature solutions of the first adjoint “quasistationary” heat conduction equations using the first time jump are easily obtainable for each regular body. For enhanced acccuracy, regression analysis is applied to the deviations of the dimensionless surface temperature as a function of the dimensionless time for each regular body.

Work is reported on thermal-induced redshifts of quantum particle plasmon. The redshifts are predicted to be caused indirectly by the quantum size effects. The particles are enlarged when temperature increases, and consequently, quantum size effects modify the plasmon but not the band structure. It has been modeled for metallic quantum particles. The results are also instructive to other quantum systems, such as complex molecules. Every electron inside the quantum particle is taken into account. Tiny quantum size effects are harvested, and the redshift becomes significant. Experimental evidence is also given for the spectral redshift. Faujasite zeolites were synthesized. Optical spectroscopy has been carried out, and the resulting spectra showed a significant redshift with the increase in temperature.

Heat transfer enhancement (HTE) is a topic of everlasting importance in thermal engineering research. The latest focuses in this field are on nanosolutions for more efficient thermal transmission fluids (a) and designs of metallic foams (b) Metallic foams provide extended surfaces for HTE and possess advantages such as a high value of Cp, high thermal conductivity (TC) and being light weight. nanosolutions, on the other hand, can be used as an efficient HT medium as they exhibit higher TCs in comparison to base fluids. This review paper summarizes the physical properties of nanosolutions and or within the metal foam, focusing on HT and flow properties of nanosolutions, metal foam and combined NS-metal foam systems. The inspiration novelty for this review is the basic transference identifications for the HT enhancement of nanosolutions in porous media. The aim of the work is to provide insight on how nanosolutions in conjunction with porous media can be useful for HTE.