A refrigeration system includes an evaporator, a compressor fluidly connected to the evaporator to compress low-pressure refrigerant exiting the evaporator to high-pressure vapor refrigerant, a high-side heat exchanger fluidly connected to the compressor to receive the high pressure vapor refrigerant and dissipate heat therefrom, and an energy recovery device configured to extract work from the high pressure refrigerant flowing therethrough, the energy recovery device including a gear expander, a generator and a controller. The gear expander having a fluid inlet, a fluid outlet in fluid communication with the fluid inlet, and a mechanical power output for outputting mechanical power created by fluid passing between the fluid inlet and fluid outlet, the fluid inlet arranged between a high pressure output of the compressor and an inlet of the evaporator. The generator is mechanically coupled to the gear mechanical power output and operative to convert mechanical power produced by the gear to electrical power. The controller is electrically coupled to the generator, the controller configured to regulate electrical power produced by the generator and output the regulated electrical power.