Triple effect absorption chillers can achieve 50% COP improvement over double-effect systems. However, to translate this potential into cost-effective hardware, the most promising embodiments must be identified.In this study, 12 generic triple effect cycles and 76 possible hermetic loop arrangements of those 12 generic cycles were identified. The generic triple effect cycles were screened based on their pressure and solubility field requirements, generic COPs, risk involved in the component design, and number of components in a high corrosive environment. This screening identified four promising arrangements: Alkitrate Topping cycle, Pressure Staged Envelope cycle, High Pressure Overlap cycle, and Dual Loop cycle.All of these arrangements have a very high COP (-1.Q however the development risk and cost involved is different for each arrangement. Therefore, the selection of a particular arrangement will depend upon the specific situation under consideration.

In an effort to increase the energy efficiency and reduce environmental emissions from refineries, the Commerce City Refinery of Ultramar Diamond Shamrock, the Office of Industrial Technologies at the U.S. Department of Energy and a team of contractors have collaborated to implement a novel project. A waste heat fired Absorption Refrigeration Unit (ARU) was designed, fabricated, installed and is currently completing a one year field test at the oil refinery in Denver, Colorado. Data is being gathered to document the performance and compare to the predictions. The ARU is designed to provide refrigeration for two process streams at the refinery while being powered by waste heat from a third process stream. The refrigeration benefits the refinery by recovering salable product and increasing the capacity of the process units with no additional electrical demand. The constraints to be satisfied by the ARU design were very stringent: low temperature waste heat; very low refrigeration temperature; limited plot space; geographically separated streams; and very limited cooling water. In order to satisfy all these constraints and to make the economics more favorable, several new concepts were developed and incorporated in the ARU. This paper describes the various cycles considered and the qualitative and quantitative considerations involved in screening the cycles. The parametric analysis and optimization of the most promising cycle is presented.

Waste heat powered absorption refiigeration is an economical and environmentally beneficial means of providing refigeration. When the temperature is too low to power a conventional single && absorption cycle, the doublelift cycle is needed. "his paper describes several recently conceptualized double-lift cycles that incorporate intemal heat exchange between the intermediate pressure absorber and the high pressure generator (termed semi-GAX). Computer modeling identified their key performance parameters. Compared to conventional double-lift cycles, the semi-GAX cycles enjoy a 20% increase in COP, and require less total heat duty, implying lower first cost.

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