A direct absorption parabolic trough solar collector (DAPTC) integrated with porous foam as a volumetric absorber has the potential to be applied as an energy conversion integrant of future renewable energy systems. The present study comprehensively analyzes a DAPTC in terms of exergy, economic, and environmental analysis for different porous configuration inserts in the absorber tube. Ten different arrangements of porous foam are examined at several HTF flow rates (40–120 L/h) and inlet temperatures (20–40 °C). The exergy efficiency, entropy generation, Bejan number, and pumping power are investigated for all cases. Obtained results indicate that fully filling the absorber tube with porous foam leads to a maximum exergy efficiency of 20.4% at the lowest inlet temperature (20 °C) and highest flow rate (120 L/h). However, the Bejan number reaches its minimum value due to the highest pumping power in this case. Consequently, all mentioned performance parameters should be considered simultaneously. Finally, the environmental and economic analyses are conducted. The results show that fully filling the absorber tube with porous foam reflects the best heat production cost, which can reduced the embodied energy, embodied water, and CO₂ emission by 559.5 MJ, 1520.8 kL, and 339.62 kg, respectively, compared to the base case at the flow rate of 120 L/h.

The utilization of porous‐fin microchannel (PFM) heat sinks has become prevalent for the cooling of microelectronic chips. This paper employs three‐dimensional simulation to examine the potential benefits of substituting a solid fin with a porous fin for enhancing the thermohydraulic performance. The influence of porous structure features on the thermal and hydraulic behavior of the PFMs at different geometrical configurations is investigated. Results show that in all configurations, employing a porous fin reduces the pressure drop. The heat transfer in PFMs is influenced by the convection in the main fluid path as well as convection in the porous fin structure. An increase in the permeability of the porous fins results in enhanced overall heat transfer due to the augmented convection within the fins. On the contrary, an increase in fin porosity leads to a heat transfer reduction as the effective thermal conductivity of the fin is diminished. The possibility of enhancing thermal performance via the substitution of the solid fin with a porous fin is diminished as the height of the microchannel increases. This is attributed to the weak vertical thermal diffusion of the porous material. Moreover, the findings indicate that the geometric configuration of microchannels has an essential role in heat transfer performance of the porous fin. For instance, the thermal resistance of the PFM with a height ratio of 1.5, porosity of 0.85, and permeability of K = 5 × 10⁻⁸m² is 10.4% less than that of the solid‐fin microchannel (SFM). However, by decreasing the permeability to K = 5 × 10⁻¹⁰m², the thermal resistance of PFM was 26% higher than that of the SFM.

Energy supply and environmental protection by reducing pollutants are among the main challenges these days. As a clean and sustainable source, solar energy is capable of generating thermal and electrical power. In this regard, Iraq is one of the regions with high solar energy harvesting potential. A numerical model was developed and validated by experimental findings in MATLAB software. This model, which also included geometrical and optical characteristics, was developed using information from four cities representative of different climates in Iraq: Baghdad, Samawa, Mosul, and Al-Qa'im. This study examined the effects of climate on the performance of direct absorption parabolic solar collectors used for energy production in Iraq. According to the results, solar collectors in Samaveh provide the highest thermal energy efficiency (up to 66.5%). Even thoth, the highest exergy efficiency is found in Al-Qa'im (36.21%). From an environmental point of view, the collector in Al-Qa'im has the highest CO₂ mitigation (2.73 kg per m² of collector) every year. As compared to other cities, Al-Qa'im and Samawah have a high thermal efficiency and solar intensity, which can lead to more water and energy savings.