Pumpless configurations for power production

The pump is an important component in thermodynamic cycles, but it needs electrical power to operate. This characteristic has an increased weight in waste heat recovery for power production since reduces significantly the power output. This work focuses on the implementation of innovative configurations of thermodynamic cycles that are able to produce power without the aid of the mechanical pump for the circulation of the working fluid. Such technologies are: • Pumpless Organic Rankine Cycle, where the role of the pump is replaced by a valve system that can change the operative function of the heat exchangers • Sorption cycle, where two adsorbent beds can release or adsorb the volatile component, that is used as working fluid for an expansion process • Gravity-driven ORC, where the maximum pressure of the cycle is achieved thanks to the height of the working fluid column • Thermosyphon Rankine Engine, where a heat pipe is modified to incorporate a turbine for power production • Thermal-driven pump, where the maximum pressure of the cycle is not mechanically imposed, but due to a thermal system that heats up the fluid in a closed container and then discharge it. The implementation of this technologies can afford to overcome some drawbacks of the mechanical pump, but may also bring about other side effects.