Evaluating the Performance of a Solar Thermal Field: A Case Study with Proposed Improvements

Abstract: Given the urgency of climate change, alternative energy sources, and policy strategies are needed to reach the net-zero emission goals and halt global warming. Solar thermal energy is a renewable and abundant energy source that could be a part of the solution. In this master’s thesis, the performance of a pilot solar thermal park in northern Sweden was modeled and evaluated based on an international evaluation standard, ISO 24194:2022 ’Solar energy—Collector fields—Check of performance’. However, due to simplifications and uncertainties in the ISO 24194:2022, a broader analysis of both the solar thermal field and the ISO 24194:2022 was made. A fault in the ISO 24194:2022 was found which makes the measured performance appear better if worse sensor maintenance and equipment were used. A suggestion for this problem was changing a parameter in the ISO 24914:2022 to mark certainty/consistency in the performance evaluation rather than impacting the actual performance calculation. By applying the ISO 24194:2022 and color coding the performance data of the solar thermal park by hour it was shown that the performance of the park had a significant dip in the middle of the day. A possible reason for this could be non-ideal tracking which is most noticeable in the middle of the day. If the tracking system would be fixed a performance increase of 2-3 % is plausible. It was also found that the park had unnecessary heat losses from the pipes above ground, which if insulated correctly could improve performance by a further 3%. Adding these improvements together a total increase in performance of 4-5% is expected, which relates to 15-20 kW.