A Method of Three-Dimensional Thermo-Fluid Simulation of the Receiver of a Standard Parabolic Trough Collector

Abstract

A parabolic trough collector (PTC) is the most proven concentrating collector system for indirect steam generation in solar thermal power plants. The receiver of the collector is fabricated enveloping a metal absorber tube using an evacuated glass tube. Depending on the level of evacuation, the glass envelope reduces the convection heat loss from the tube almost to zero. However, sometimes the envelopes are broken, damaged or removed that causes potential convection loss from an open-to-air receiver tube. On the other hand, the solar irradiance profile around the receiver tube is likely to be highly nonuniform. In order to study the heat transfer mechanism of an exposed receiver tube of a standard PTC under the actual optical and environmental conditions, a 3-dimensional Computational Conjugate Heat Transfer (CCHT) model of the receiver tube was developed. The CCHT model was developed applying finite volume technique of computational fluid dynamics integrating with a verified Monte Carlo ray tracing optical model. The CCHT model was verified extensively, and different heat loss models were developed to investigate the heat loss characteristics. The convection heat loss from the outer surface of the receiver tube was observed very high as it was exposed to a high-temperature gradient with its surroundings. Therefore, it is obvious that the receiver tube should be enveloped and evacuated properly. A well-managed and efficiently operated PTC solar energy field could be the best candidate for sustainable energy management for a sustainable future.