An Innovative Application of a Solar Storage Wall Combined with the Low-Temperature Organic Rankine Cycle

The objective of this study is to collect energy on the waste heat from air produced by solar ventilation systems. This heat used for electricity generation by an organic Rankine cycle (ORC) system was implemented. The advantages of this method include the use of existing building’s wall, and it also provides the region of energy scarcity for reference. This is also an innovative method, and the results will contribute to the efforts made toward improving the design of solar ventilation in the field of solar thermal engineering. In addition, ORC system would help generate electricity and build a low-carbon building. This study considered several critical parameters such as length of the airflow channel, intensity of solar radiation, pattern of the absorber plate, stagnant air layer, and operating conditions. The simulation results show that the highest outlet temperature and heat collecting efficiency of solar ventilation system are about 120°C and 60%, respectively. The measured ORC efficiency of the system was 6.2%. The proposed method is feasible for the waste heat from air produced by ventilation systems

Hopf bifurcation to a short porous journal-bearing system using the Brinkman model: weakly nonlinear stability

Abstract On the basis of the Brinkman model, the weakly nonlinear stability characteristics of short porous journal-bearing systems are presented. By applying the Hopf bifurcation theory, the weakly nonlinear behaviors near the critical stability boundary are predicted. According to results, the onset of oil whirl for porous bearings is a bifurcation phenomenon; it can exhibit supercritical limit cycles or subcritical limit cycles for journal speeds in the vicinity of the bifurcation point. With a fixed permeability parameter, such supercritical limit cycles for journal speeds in excess of the threshold speed are confined to a specific region in the (w, ⑀ s ) plane; and outside this region subcritical limit cycles exist for journal speeds below the threshold speed. In addition, increasing the value of system parameter, S p , may change supercritical bifurcation into the more complicated subcritical bifurcation

Effects of elastic ball and coating on pure squeeze EHL motion for constant load with couple stresses using FDM method

In this paper, an elastic sphere approaching a lubricated elastic coating surface with couple stress lubricant is explored under constant load condition. The finite difference method (FDM), Gaussian elimination, and Gauss-Seidel iteration method are used to solve the transient modified Reynolds equation with its boundary condition, the elasticity deformation equations of ball and coating layer, load balance equation, and lubricant rheology equations simultaneously. The transient pressure profiles, film shapes, and elastic deformation during the pure squeeze process under various operating conditions in the elastohydrodynamic lubrication (EHL) regime are discussed

Effects of elastic ball and coating on pure squeeze EHL motion for constant load with couple stresses using FDM method

In this paper, an elastic sphere approaching a lubricated elastic coating surface with couple stress lubricant is explored under constant load condition. The finite difference method (FDM), Gaussian elimination, and Gauss-Seidel iteration method are used to solve the transient modified Reynolds equation with its boundary condition, the elasticity deformation equations of ball and coating layer, load balance equation, and lubricant rheology equations simultaneously. The transient pressure profiles, film shapes, and elastic deformation during the pure squeeze process under various operating conditions in the elastohydrodynamic lubrication (EHL) regime are discussed