In this research a prototype flat-plate solar-thermal collector that uses wickless-heat-pipes and parallel coolers is developed and evaluated. The study conducted indoor-experiments using a solar simulator to assess collector’s thermal performance. Design details and an exergy analysis of the collector are provided. The investigation aimed to improve the efficiency of flat-plate solar collectors for low-temperature applications by integrating heat-pipe technology. The study examined various experimental-parameters, including collector’s tilt-angles (5,10,20,30,40°), solar irradiance levels (475,625,850,1050 W/m²), water flow-rates (0.0235-0.0387 kg/s), and inlet temperatures (30,35,40,45 °C). The results showed that inlet, outlet, and gained exergy values are increased positively with higher water flow rates and inlet temperatures. Higher inlet temperatures, in particular, led to significant increases in exergy gains, inlet fluid exergy, and outflow exergy. The higher exergy losses are due to the temperature difference between the absorber-plate of the solar-collector and the Sun's surface. The uncertainty of the solar-experiments is found =7.299%.