Heat pump system comprising: - a first hydraulic circuit adapted to carry out a heat pump cycle with a first operating fluid which, during part of said cycle, is associated with at least one auxiliary substance so as to form a material system therewith, said first hydraulic circuit comprising: - a first treatment device for said material system, at which at least a fraction of the first operating fluid is separated from said material system; - a first condenser, at which the first operating fluid which has been separated at least partially condenses, thus releasing heat; - a first evaporator, at which the first operating fluid which has been condensed at least partially evaporates, thus absorbing heat, and - a second treatment device for said material system, at which the first operating fluid which has been evaporated is again incorporated in said material system; - a second hydraulic circuit suitable to carry out a compression heat pump cycle with a second operating fluid, said second circuit comprising: - a second condenser, at which said second operating fluid at least partially condenses, thus releasing heat, - a second evaporator, at which said second operating fluid evaporates, thus absorbing heat, and - a compressor for compressing the evaporated second operating fluid and returning it to entry conditions of pressure and temperature of said condenser, wherein said second condenser is thermally coupled with said first treatment device to transfer heat released from said second operating fluid at said second condenser to said first treatment device for separating said at least one fraction of the first operating fluid from said material system; wherein said material system is a liquid solution; wherein at said first treatment device at least a fraction of said first operating fluid is separated, by heating, from said liquid solution so that there exit from the generator a solution poor of said first operating fluid and of said first operating fluid in the vapour state and wherein said first operating fluid in the vapour state is delivered to said first condenser; wherein said fist hydraulic circuit comprises a recirculation line to delivery said solution poor of first operating fluid up to said second treatment device at which said first operating fluid in the vapour state is mixed with said solution poor of said first operating fluid so as to obtain a solution rich in operating fluid; and wherein said first hydraulic circuit comprises a pump to deliver said solution rich in operating fluid from said treatment device to said first treatment device; characterized in that said first hydraulic circuit comprises a regenerative heat exchanger arranged between said recirculation line and said pump so as to pre-heat said solution rich in operating fluid as it enters the generator by recovering heat from said solution poor in said first operating fluid discharged from said generator. - a first hydraulic circuit adapted to carry out a heat pump cycle with a first operating fluid which, during part of said cycle, is associated with at least one auxiliary substance so as to form a material system therewith, said first hydraulic circuit comprising: - a first treatment device for said material system, at which at least a fraction of the first operating fluid is separated from said material system; - a first condenser, at which the first operating fluid which has been separated at least partially condenses, thus releasing heat; - a first evaporator, at which the first operating fluid which has been condensed at least partially evaporates, thus absorbing heat, and - a second treatment device for said material system, at which the first operating fluid which has been evaporated is again incorporated in said material system; - a second hydraulic circuit suitable to carry out a compression heat pump cycle with a second operating fluid, said second circuit comprising: - a second condenser, at which said second operating fluid at least partially condenses, thus releasing heat, - a second evaporator, at which said second operating fluid evaporates, thus absorbing heat, and - a compressor for compressing the evaporated second operating fluid and returning it to entry conditions of pressure and temperature of said condenser, - a second condenser, at which said second operating fluid at least partially condenses, thus releasing heat, - a second evaporator, at which said second operating fluid evaporates, thus absorbing heat, and - a compressor for compressing the evaporated second operating fluid and returning it to entry conditions of pressure and temperature of said condenser,