Gravitational heat pipes for discontinuous applications

Gravitational heat pipes or thermosiphons (TS) are simple and efficient hea t exchangers. This paper deals with the adaptation of these exchangers to d iscontinuous or cyclic processes such as chemical heat pumps. Such TS must fulfil a two-mode working too: the TS working must be active/inactive accor ding to the successive endothermal/exothermal phases of the cyclic process. Two kinds of TS blockage processes have been successfully experimented: th ey act either on the liquid or on the vapor phase inside the TS. A simple m odel demonstrates that realistic configurations of TS and reactor can easil y reduce the energy and duration required by the blockage process itself on the performances of the coupling. (C) 2001 Elsevier Science Ltd. All right s reserved.