Energy conversion performance investigations for a horizontal evacuated tubular collector

Abstract

Purpose

The purpose of this paper is to use numerical simulations to investigate the energy conversion performance and the flow and temperature structures inside horizontal tubes connected to a vertical manifold channel.

Design/methodology/approach

The simulations are performed for different flow rates and inlet temperatures using CFD.

Findings

In both the “flowing wind mode” and “upwind mode,” the inlet velocity is not infinitely small under the influence of natural convection; however, such small inlet velocities cannot be achieved in practice and are of no practical significance. In the “flowing wind mode,” the appropriate velocity for achieving high efficiency is 0.01-0.02 m/s. In the “upwind mode,” the appropriate velocity for obtaining high efficiency is 0.1-0.2 m/s. A high inlet temperature can lead to high efficiency; therefore, a large temperature difference and a small flow can be used in actual designs.

Originality/value

The energy conversion performance and flow structures inside evacuated tubular collectors were investigated using CFD for different operating conditions, notably in the “following wind mode” and the “upwind mode.”

Citation

Zhao, C., You, S., Gao, H. and Yu, W. (2016), "Energy conversion performance investigations for a horizontal evacuated tubular collector", International Journal of Numerical Methods for Heat & Fluid Flow, Vol. 26 No. 1, pp. 146-158. https://doi.org/10.1108/HFF-03-2015-0111