A reversible system for dissipating heat power generated in a gas turbine engine, the system including a condenser-forming first heat exchanger, an evaporator-forming second heat exchanger, a scroll compressor suitable for operating as a compressor when the temperature of the cold source is higher than a predefined threshold temperature and as a turbine when the temperature of the cold source is lower than the threshold temperature, an expander and a pump arranged in parallel, and a control valve arranged upstream from the expander and the pump and suitable for directing the refrigerant fluid to the expander when the temperature of the cold source is higher than the threshold temperature and to the pump when the temperature of the cold source is lower than the threshold temperature.