Influence of cooling temperature increase in a hygroscopic cycle on the performance of the cooling equipment

Abstract

Power output of power plant is substantially reduced when cooling is conducted at high ambient temperatures. The problem is also intensified at locations with water scarcity. Hygroscopic cycle is a novel technology that improves Rankine cycle and solve those problems in an effective way. Hygroscopic Cycle Technology works with hygroscopic compounds that increase the cooling temperature for each output pressure of the steam turbine and uses dry coolers for refrigeration. As a result, much better cooling conditions are obtained and water consumption is avoided. Higher electrical performance is obtained without the limitation of high ambient temperatures. In this paper, Hygroscopic Cycle is experimentally studied. Results have been obtained in a test plant with a live steam generation capacity of 110 kg/h. This article shows cooling temperatures increase obtained for high mass concentrations from 45 to 65% of lithium bromide solution in water at the cooling reflux stream. The increase of the saline concentration in the cooling reflux significantly increase the cooling temperatures by more than 15 °C in a Hygroscopic cycle with respect to a Rankine cycle, for the same condensing pressure. Consequently, it reduces the electrical power required by the chosen cooling system, as well as to save all the cooling water consumption needed for cooling towers in other installations. Hygroscopic Cycle with high concentrations is able to increase up to 17.41% the net electrical power output respect to Rankine cycle.