Systems and methods for collecting solar energy and converting it to heat, mechanical work, or electricity on a small scale and utilizing one or more system components originally adapted for use in a non-solar-power-generation application are described. Solar energy is used to heat a fluid that is part of a solar energy collector. This fluid transfers heat to the working fluid of thermodynamic engine, which converts some of the heat into mechanical work or electricity. One or more system parameters are monitored and controlled to enable improved efficiency under variable environmental conditions.