Abstract: A heat pump device and method of controlling the heat pump device which includes a cold generating fluid circuit, a first heat exchanger associated with the circuit in order to draw calories from a heat containing fluid passing through a cooling circuit, and a second heat exchanger associated with the circuit in order to transmit calories to a fluid passing through a utilization circuit.The method comprises the steps of controlling the flow of heat-carrying fluid through the first heat exchanger in dependence upon the temperature of the fluid of the utilization circuit at the output of the second heat exchanger, and controlling the flow of fluid from the utilization circuit through the second heat exchanger in dependence upon the temperature or pressure of the cold generating fluid at the outlet of the second heat exchanger.