Abstract: An arrangement for exchanging heat between the environment and a heat-transfer fluid, especially a solar heat absorber, includes a plurality of heat exchange elements which are provided with external fins and have internal flow-through passages for the fluid. The heat exchange elements are mounted on and the passages thereof communicate with internal channels of collector pipes. The collector pipes are, in turn, connected by respective corner members to connecting pipes to form a frame therewith. Such a frame, together with the heat exchange elements mounted therein, constitutes a heat-exchanger unit. A plurality of such heat-exchanger units can be arranged next to one another and/or above another in substantially vertical positions, to form an energy fence or a protective wall with heat-exchange capability. Then, the connecting pipes of the individual heat-exchanger units are connected to one another to establish a continuous flow pattern of the heat-transfer fluid through the arrangement.