Cold and/or heat production involving an absorption cycle and its use for heating buildings

Claim 1

An improved process for cold and/or heat production, in an absorption cycle operating with a working fluid (F) as a solute, and a fluid (S) as the solvent, the boiling temperature of the fluid (S) being higher than the boiling temperature of the fluid (F), and said cycle comprising at least one absorption step, at least one desorption step, at least one rectification step for the vapor withdrawn from the desorption step, at least one condensation step and at least one vaporization step, the improvement comprising the steps of: (a) vaporizing, in the vaporization step, a portion of the liquid phase (L 1 ) of high fluid (F) content, obtained in the condensation step (d), taking the necessary vaporization heat at least partly from an external fluid, recovering a vapor phase (V 1 ) and a liquid phase (L 2 ), separating said vapor phase (V 1 ) from said liquid phase (L 2 ), and fractionating said liquid phase (L 2 ) into at least one first fraction and at least one second fraction, (b) contacting the vapor phase (V 1 ) from the step (a), in the absorption step, with a liquid phase (L 3 ) of low fluid (F) content and high fluid (S) content from the desorption step (c), delivering heat to an external fluid, and recovering a solution (S 1 ) of increased fluid (F) content, (c) feeding at least one portion of the solution (S 1 ) from step (b) to an intermediate point of a rectification zone wherein the rectification step is effected, flowing said portion of the solution (S 1 ) downwardly in said rectification zone, supplying heat at the bottom of said rectification zone by means of a heating fluid, so as to effect said desorption step of said solution (S 1 ) and to obtain a vapor phase (V 2 ) and a desorbed liquid phase (L 3 ), withdrawing said liquid phase (L 3 ) and feeding it to step (b), introducing said first portion of the liquid phase (L 2 ) from step (a) into said rectification zone, at the top thereof, flowing said first portion downwardly in said rectification zone, circulating said vapor zone (V 2 ) upwardly in said rectification zone, and withdrawing a vapor phase (V 3 ) from the top of said rectification zone, and (d) mixing said vapor phase (V 3 ), withdrawn from the top of said rectification zone, with said second portion of the liquid phase (L 2 ) from the step (a), cooling the resultant mixture by heat exchange with an external fluid, in the condensation step, so as to form said condensed liquid phase (L 1 ), and feeding said phase (L 1 ) to the step (a).