AbstractIn this research, the small segments parabolic dish concentrator (SSPDC) with a modified cavity was optically and thermally investigated. The SSPDC consisted of small mirrors that were tracking the sun individually. The SSPDC allows using different concentration ratios and aperture areas. Oil, pure water, and water + perypolen glycol (PG) were evaluated as working fluids. Different structural characteristics of the solar system were investigated, including dish focal distance, cavity outer diameter, and cavity aperture area. Then the investigated solar system was explored as a heat source of an organic Rankine cycle (ORC) unit for providing the power for a house. Finally, some environmental parameters of the investigated ORC units, such as carbon dioxide emission and carbon dioxide credits, were evaluated. The results reveal that the investigated solar unit had a dish depth of 0.14 m, a focal distance of 1 m, a cavity aperture outer diameter of 0.1 m, and a cavity aperture inner diameter of 0.08 m for a 10‐mrad optical error and a 1° tracking error. Usage of pure water is recommended for low‐temperature application, water + PG for medium‐temperature application, and oil for high‐temperature application. It was concluded that two units of the proposed ORC could provide energy to the house with solar radiation of more than 800 W/m2 and the number of units should be increased for achieving the required power with decreasing solar radiation.