Absorption Refrigeration Systems. A double effect ARS

Energy efficiency absorption can be improved by the recovery of the heat, as a rule, a cooling tower circuit. A two-stage or two-effect ARS this is achieved by taking vapor driven off by heating of the first turn of concentrating factory (or generator) ward off more water in the second stage. Many ARS manufacturers offer this increase in efficiency of the alternative.

A double effect ARS takes absorption to the next level. The easiest way to image the double effect of the cycle is to think of two single-effect cycles stacked on top of each other (as shown in Fig. 3.50). Please note that two separate shells are used. The smaller of the first turn of concentrating factory. The second building, essentially, one effect, ARS than before, containing a hub, condenser, evaporator, and ARS. Values of temperature, pressure and concentration of solutions in the big shell similar one-effect of ARS. Cycle top caused either directly by natural gas or oil burners or indirectly, by means of steam. Heat is added to the generator finishing cycle (main generator), which generates the refrigerant vapor at a relatively high temperature and pressure. Vapor is then condensed at this higher temperature and pressure and heat of condensation is used to drive the generator of the lower cycle (for the secondary generator), which at lower temperatures. If heat is added generator thoughts equivalent heat of condensation of the refrigerant, it becomes clear where the increase of efficiency comes.

For every unit of heat in the main generator, two of the refrigerant mass cooked solution, or generated: one primary and one generator in the secondary generator. One effect only one cycle of mass is created. Thus, in the double effect of the system, double-refrigerant mass flow is transmitted via the refrigerant cycle per unit of heat, which is two times more cooling is supplied per unit of heat. Using this approach the double-effect systems AB the constitutional court, which is about twice that of single-effect cycle. However, this simplifying assumption does not take into account the cycle of inefficiencies and losses. In fact, one effect of the KC about 0.65, and a double effect system COP around 1.0. Please note that repeated use of a pair of first stage generator makes this machine more efficiently than one stage of absorption chillers, as a rule, approximately 30%.