Effects of Thermal Performance Enhancement on PTC Downsizing With Emphasis on Cost Savings and Commercial Feasibility: An Extended Evaluation Criterion

Abstract

This study proposes a new comparative analysis and introduces a new criterion for evaluating the size reduction of heat exchangers, particularly relevant in the context of parabolic trough receivers. Various innovative receivers from the literature, employing different enhancement techniques, were compared with the conventional straight receiver. On the basis of the principle of similarity and using a previously validated one-dimensional mathematical model and numerical code, a parametric analysis was used to estimate reduction ratios and sizes for different solar receivers. For well-defined receiver geometries, the main results reveal consistent reduction ratios of around 99.7% and 93.53% for helical screw-tape and wavy receivers, respectively. This translates to size reductions of approximately 0.3 and 6.5 m compared with a 100-m-long conventional straight receiver, respectively. By integrating the ratio and the performance evaluation criterion (PEC) into a unified metric mPEC = PEC/, which accounts for both effectiveness and size reduction, a new classification of receivers is derived, closely aligning with that obtained by the ratio. In addition, a rebalancing analysis of the increased load loss is conducted based on this ratio. It suggests that in a scenario where the wavy receiver replaces the conventional straight receiver in operation, there would be no need to increase pumping power, as its reduced size compensates for the increased pressure drop. This scenario was used to assess the economic impact of a parabolic trough collector power plant in Hassi R'mel (Algerian Sahara). Without any additional components to boost performance, the adoption of the wavy receiver led to significant gains in terms of useful surface area, cost, and length, resulting in savings of over €3.02 million for this 30 MW solar energy field.