Combined Actions of Capric–Lauric Acid on Latent Heat and Phase Change Performance Behavior of Space Cooling Featured With Parabolic Trough Solar Collector

ABSTRACT Parabolic trough collectors (PTCs) are promising solar thermal technologies for space cooling and other medium‐temperature heat applications. However, thermal loss and limited heat‐storage capability could restrict their overall performance. This study investigates a PTC‐based space cooling system integrated with 1 wt% TiO 2 –SiO 2 hybrid nanofluids and a binary fatty‐acid phase change material (PCM) consisting of Capric Acid (C 10 H 20 O 2 ) and Lauric Acid (C 12 H 24 O 2 ). The TiO 2 –SiO 2 nanoparticles were mixed in an equal ratio, and the system was operated at a mass flow rate of 0.03 kg/s. Also, various Capric Acid/Lauric Acid ratios were evaluated to assess their influence on the system's thermal and heat‐storage characteristics. The thermal conductivity, thermal diffusivity, latent heat, PCM temperature, and thermal efficiency were evaluated and compared to show optimum PCM compositions. Among the tested compositions, the 75:25 Capric Acid/Lauric Acid ratio exhibited the best overall thermal performance, with a maximum thermal conductivity of 0.835 W/m·K, a latent heat of 153.6 kJ/kg, a thermal diffusivity of 2.20 × 10 −7 m 2 /s, and a PCM temperature of 139.8°C. The corresponding PTC system achieves a maximum average thermal efficiency of 73.4%. The results demonstrate that TiO 2 –SiO 2 hybrid nanofluids with binary Capric Acid/Lauric Acid PCM could simultaneously enhance heat‐transfer and thermal‐storage characteristics. The 75:25 PCM compositions therefore provide a suitable thermal storage configuration to improve the performance of PTC‐based space‐cooling applications.