A combined power and cooling cycle modiﬁed to improve resource utilization efﬁciency using a distillation stage S. Vijayaraghavan 1 , D.Y. Goswami * Mechanical and Aerospace Engineering Department, University of Florida, P.O. Box 116300, Gainesville, FL, USA Received 3 June 2004 Abstract A combined power and cooling cycle is being investigated. The cycle is a combination of a Rankine cycle and an absorption refrigeration cycle. The vapor exiting the turbine in this cycle is cold enough to extract refrigeration output. This combined cycle is being proposed for application with lower temperature heat sources such as solar, geothermal, and industrial waste heat with the primary objective of producing power. In this paper, the goal is to optimize the cycle conﬁguration for maximum resource utilization efﬁciency (RUE). Based on an exergy analysis, the cycle conﬁguration has been modiﬁed to improve the RUE. A thermal distillation scheme, similar to those found in some Kalina cycles has been implemented in the cycle. An optimization method is used to maximize the RUE of the modiﬁed conﬁguration. A signiﬁcant improvement in the efﬁciency of more than 25% was achieved with the improved conﬁguration. Larger pressure ratios are obtained across the turbine. Increased efﬁciencies can also be obtained for the cases where only work output is desired. q 2005 Elsevier Ltd. All rights reserved. 1. Introduction A combined cycle yielding power and refrigeration for low-temperature heat sources was proposed by Goswami [1] in 1995. The cycle can be considered to be a combination of the Rankine cycle and an absorption refrigeration cycle. The proposed cycle is suitable as a bottoming cycle using waste heat from conventional processes or utilizing relatively low-temperature solar or geothermal renewable resources. Energy 31 (2006) 1177–1196 www.elsevier.com/locate/energy 0360-5442/$ - see front matter q 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.energy.2005.04.014 * Corresponding author. Tel.: C1 352 392 0812; fax: C1 352 392 1071. E-mail address: goswami@uﬂ.edu (D.Y. Goswami). 1 Tel.: C1 352 392 2328; fax: C1 352 846 1630.