Absorption cycle system having dual absorption circuits

Abstract

An absorption cycle system utilizes an additional absorption circuit in conjunction with a traditional absorption circuit. The absorbent used in the additional absorption circuit could contain an ionic compound, or any absorbent with relatively low crystallization. Mixtures of such absorbent with water remain liquid at temperatures lower than the minimum feasible operating temperature of the traditional lithium bromide water absorbent solutions of the prior art.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application claims the priority benefit of U.S. Provisional Patent Application No. 61 / 118,042, filed Nov. 26, 2008.BACKGROUND[0002]1. Field of the Disclosure[0003]The present disclosure relates to an absorption cycle system which has dual absorption circuits. Such a system is useful in a wide range of absorption cycle applications including low temperature refrigeration, comfort air conditioning and space heating.[0004]2. Description of Related Art[0005]Single effect absorption cycle systems with a single absorption circuit are known in the art. In a typical absorption cycle system, a refrigerant, such as water vapor, is absorbed into an absorbent mixture, such as an aqueous lithium bromide (LiBr) solution, and then is released out of the absorbent mixture. The absorber is part of a single absorption circuit, which includes a pump, a heat exchanger, an expansion or pressure reduction device and a generator, where the refrigerant is r...

AI Technical Summary

Benefits of technology

[0009]With such a system, the additional absorber can be operated at lower temperatures than a traditional absorber which circulates lithium bromide and water as the absorbent / refrigerant mixture. A lower feasible absorber operating temperature is expected to enable novel cooling and heating applications especially for low ambient temperatures. A lower feasible absorber operating temperature is expected to also enable higher cycle energy efficiency, which is expressed in the industry as a higher coefficient of performance, or COP.

[0010]In addition, the use of two absorption circuits allows the simultaneous use of thermally sensitive absorbents (such as thermally sensitive ionic compounds or absorbent formulations containing thermally sensitive crystallization suppressants or other thermally sensitive additives) in one circuit and high-temperature heat sources in the other circuit.

[0012]According to another embodiment of the present invention, some of the heat from the high pressure refrigerant vapor may be recovered and transferred to the first generator, instead of being rejected at the condenser. This results in higher energy efficiency. Thus, in accordance with this embodiment, the absorption cycle system of the present invention includes a heat recovery line extending between the second generator and through the first generator for recovering heat from the refrigerant exiting the second generator. The heat recovery line continues from the first generator to the condenser, for delivering the refrigerant vapor to the condenser.

Problems solved by technology

However, a drawback of such a standard system, which typically uses lithium bromide and water as the absorbent / refrigerant pair, is that the minimum feasible absorber operating temperature is limited by the crystallization temperature of the absorbent / refrigerant mixture.

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