Research PaperYearly performance of low-enthalpy parabolic trough collectors in MENA region according to different sun-tracking strategies

- Detailed thermo-optical model of PTCs with MATLAB code is presented.
- Climatic conditions affect significantly the PTC overall performance.
- Best yearly heat generation (154.57 MWh) is predicted in Ouarzazate, Morocco.
- Polar E-W is the most cost effective tracking technique for such applications.

Solar parabolic trough collector (PTC) is a very popular system in solar concentration technology, which is widely used for electric production and heat generation in industrial processes. In this paper, a validated mathematical model has been proposed to evaluate the performance of low-enthalpy PTC in five sites of the MENA region: Ouarzazate (Morocco), Gafsa (Tunisia), Jeddah (Saudi Arabia), Amman (Jordan) and Aswane (Egypt). A MATLAB program was developed to simulate the hourly thermal performance of the PTC under fluctuating climatic conditions. A particular attention has been given to the effect of the sun-tracking technique on the collector's performance. The model validation was carried out in two phases: first, by comparison with the results generated by the System Advisor Model software, and second by comparison with experimental data. In both cases, a very close agreement is obtained. The results have shown clearly that the tracking technique, climate and season of the year have a significant impact on the PTC performance. The best site for implementing such technologies was found to be Ouarzazate (Morocco) with a useful annual energy generation potential varying from 104.85 to 154.57 MWh. On December 24, the PTC operating in Ouarzazate using 0.2 kg/s mass flow rate, the outlet water temperature can achieve a maximum temperature of 70 °C using the full-tracking and N-S tracking techniques, while the outlet temperature does not exceed 46.5 °C using the E-W tracking. This temperature can reach 82 °C on July 07, by using the full-tracking and E-W tracking modes. From a general aspect, it was also concluded that the optimal cost-effective tracking strategy for the annual heat generation is the E-W polar tracking one independently of the geographical location.