The work emphasis on the energy storage and photosensitivity of in-situ formed silver-copper (Ag-Cu) bimetallic nanoparticles generated using developed Micro-Electro Discharge Machining (Micro-EDM) process. The investigation includes analysis of useful heat gain, temperature gain, and thermal efficiencies by the nanofluids with the help of fabricated mini parabolic solar trough collector. The photosensitivity of nanoparticles is studied by evaluating light absorbance and bandgap energies at different light intensities. The theoretical study includes an understanding of the effects of the metallic vapor pressure, dielectric temperature, and material properties on bimetallic particle formation mechanisms. The experimentation work comprises of conduction of ten experiments by keeping silver plate (workpiece) at anode terminal and varying copper multi-tool pins from 1, 2, 3…10 at cathode terminal submerged in deionized water with 0.7 mM concentration of CTAB surfactant. Particles generated are found to be well dispersed, segregated, and alloyed structures with average particle size ranging from (4.83 ± 3.35) nm in 3rd experiment to (15.37 ± 5.46) nm in 5th experiment. XRD crystallographic studies confirmed the presence of the FCC structure of Ag and BCC structure of Cu2O. Maximum particle synthesis is from the 9th experiment producing 5.4 g/L for 30 min of machining with the spark energy of 2.88 mJ. The highest useful heat gain is obtained by the 3rd experiment due to higher silver content whereas the highest overall thermal efficiency of 14.5 % and bandgap energy of 2.75 eV is obtained by the 7th experiment nanofluid.