Abstract: A device (200) for the exchange of thermal energy between an interior of a housing, more particularly for a telecommunication apparatus and an environment, in order to convey heat from the housing interior to the outside and, in this case, in order to maintain the internal temperature for the components involved within tolerated limits one heat exchanger block (11) possesses two fluid duct systems (12,16) which are separated from each other and that are in thermal energy-transmitting contact with each other, while a first fluid duct system (12) communicates with the housing interior and a second fluid duct system (16) communicates with the surroundings and each fluid duct system (12,16) has allocated to it one fluid pump (22,24) each for conveying a first working fluid (18) in the first fluid duct system (12) and a second working fluid (20) in the second fluid duct system (16).