Ever since the rapid increase in both the demand for the miniature electronic devices and their applications, heat dissipation in the electronic components has been a serious issue. A miniature plate‐pin heat sink model with square, circular, and elliptic pins is considered to enhance the hydrothermal performance of this kind of compact heat sink (CHS). Water and 3% of SiO2‐water nanofluids of volume fraction were used with different Reynolds number ranges (100‐1000). The findings show that the base temperature of heat sink reduces while the Nusselt number enhances by using nanofluids and increasing Reynolds number. The lowest value of the base temperature is nearly 25% for the square pins and circular pins CHSs compared with a plate–fin heat sink at 3% of nanofluids. Furthermore, the highest value of the Nusselt number is about 98% at 3% SiO2 for circular pin CHSs compared with the plate–fin heat sink. However, the pressure drop of CHSs is higher than that of plate–fin heat sink. Moreover, the most significant hydrothermal performance value is about 1.44 for water and around 1.51 for SiO2 as using the CHS with circular and elliptic pins depends on the Reynolds number. Thus, applying CHSs with nanofluids instead of the traditional heat sinks might produce a substantial enhancement in the hydrothermal performance of heat sinks.

The generated heat from photovoltaic (PV) cells, electronic device, transformer, internal combustion (IC) engine, and so forth can be mentioned as the most critical issues confronting modern industries. Leading to high temperature causes a problem in devices and sometimes cause damage. A mini‐heat sink is one of the common ways to cool and remove created heat from these engineering devices. This research used compact heat sinks, combined pins, and plate fins, with using SiO2‐water nanofluids for enhancing the hydro‐thermal performance and entropy generation of heat sinks. The computational investigation and simulation of compact heat sinks are performed by using ANSYS‐FLUENT 14.5. The compact heat sinks include three different pins cross‐section: circular (PCP), square (PSP), and elliptic (PEP) as well as flat finned heat sinks as a standard case. SiO2‐water nanofluids with the various nanoparticles volume fraction of 0% to 5% have been examined for Reynolds number range between 100 and 1,000. The main data display that the supreme Nusselt number is for PCP around 93% and 100% for 0% and 5% SiO2‐water, respectively compared with plate fins heat sink. The PCP and PSP have the lowest base temperature, around 25% for 0% and 5% nanofluids. Furthermore, at Re = 1,000, the highest hydro‐thermal performance is for PEP at 1.44 and 1.52 for pure water and SiO2‐water, respectively. While, the most magnificent hydro‐thermal performance is for PCP at 1.44 and 1.50 for pure water and SiO2‐water, respectively, as Re = 800. Moreover, the PCP and PSP have the smallest total entropy generation, approximately 42% for pure water and 5% SiO2‐water among other heat sinks. Thus, it is recommended to use this kind of heat sinks with nanofluids instead of traditional coolant of PV cells.