Inverse Heat Transfer Analysis for Estimating Heat Flux in Solar Tower Receivers

Abstract

Solar power tower plants are utilized to harness solar radiation for large-scale electricity generation. The concentrated solar radiation is absorbed by the central receiver to heat a transfer fluid, which is typically a mixture of 60% sodium nitrate (NaNO₃) and 40% potassium nitrate (KNO₃) to temperatures up to 565°C. Extreme conditions, including high temperatures and variable heat flux, are experienced by these central receivers, necessitating precise thermal measurements to optimize energy production and maintain efficiency. In this paper, an in-house code based on an inverse analysis technique is developed to determine the absorbed heat flux on the surface of the concentrated solar power (CSP) receiver tube, using surface temperature measurements as input. It is found that a single temperature measurement from the frontal part of the tube (0 ≤ θ < 90°) is sufficient for the estimation of the absorbed flux within an acceptable deviation. Additionally, noise is incorporated into the input temperature data to evaluate the reliability of the code under fluctuating conditions typical of real-world applications. The effectiveness of the code in this scenario is demonstrated, reinforcing its potential for practical applications.