Polybranched regenerative GAX cooling cycles

doi:10.1016/0140-7007(95)00012-Z

International Journal of Refrigeration

Volume 18, Issue 5, 1995, Pages 318-329

https://doi.org/10.1016/0140-7007(95)00012-Z Get rights and content

Abstract

After a short characterization of today's advanced absorption cooling systems, of multi-effect and generator-absorber heat exchange (GAX) type, this work introduces polybranched regenerative GAX cycles (PBR(GAX)). They combine the advantages of four cycles: GAX, branched GAX, regenerative GAX, and those with rectification heat recovery. The general case of n-stage PBR, working with volatile or non-volatile absorbents, is thermodynamically modelled. The model is applied to cycles with one to three stages working with the $NH_{3} H_{2} O  LiBr$ combination, selected according to a special criterion, which has in view to maximize the GAX effect. The thermal match in the GAX device is verified using our own complete algorithm. The results highlight the net superiority of the cooling COP of PBR relative to any other published GAX or multi-effect cycles. Compared with those with vapour exchange, operated with $NH_{3} H_{2} O$ , one of the best GAX cycles till now, a three-stage PBR has 1.25–1.9 times higher COP values and represents 71–82% of the Carnot cooling efficiency for lifts varying between 68 and 47°C. The PBR cycles are capable of simultaneously delivering cold and warm water, at 50–70°C. Compared with a double-effect cycle, provided with rectification heat recovery, a two-stage PBR is constructively simpler and thermally with about 40% more performance.

Résumé

Après une brève présentation des systèmes actuels de pointe de refroidissement à absorption à effet multiple et àéchange de chaleur pár génération et par absorption (GAX), ce rapport introduit les cycles à GAX régénératifs multiramifies (PBR (GAX)). Ceux-ci associent les avantages de quatre cycles: celui à GAX, celui à GAX ramifié, celui a GAX régénératif et celui à récupération rectificative de chaleur. nélabore un modèle thermodynamique du cas général des cycles PBR à l'étage n, fonctionnant avec des absorbants volatils ou non. Ce modèle est appliqué aux cycles ayant un, deux ou trois étages fonctionnant avec la combinaison $NH_{3} H_{2} O  LiBr$ : ces cycles ont été choisis en fonction d'un critère particulier, à savoir l'augmentation au maximum de l'effet de GAX. L'adéquation thermique dans le dispositif du COP au refroidissement des cycles PBR, par rapport à tutre cycle connu à GAX ou á effet multiple. Par rapport à l'un des meilleurs cycles à GAX connus jusqu'ici, à savoir celui à echange de vapeur fonctionnant au $NH_{3} H_{2} O$ , le cycle PBR à trois étages présente des COP de 1, 25 à 1, 9 fois plus élev́s et un rendement de Carnot égal à 71 à 82% pour une hausse de température allant de 68 à 47°C. Les cycles PBR sont également capables de produire simultanément de l'eau froide et chaude à 50–70°C. Par rapport à un cycle à double effet, un PBR bi-étagé, muni de récupération rectificative de chaleur est d'une construction plus simple, tout en ayant une performance supérieure de 40%.

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Polybranched regenerative GAX cooling cyclesCycles de refroidissement régénératifs et multiramifiés utilisant des échangeurs de chaleur á absorption et à génération

Abstract

Résumé

Solar Energy

JSME-Int J Ser II

Letter to Prof. G. Alefeld

Energetica suppl

Advanced absorption cycles for environmental protection

Future developments in thermal absorption cycle technology

Regeln für den Entwurf von mehrstufigen Absorber maschinen

Brennst-Wärme-Kraft

Compression- und Expansionsmaschinen in Verbindung mit Absorberkreislaufen

BWK

Der Wärmepumpentransformator, ein Gerät zur Nutzung ‘kalter Fernwärme’

Brennst-Wärme-Kraft

One-and-a-half effect absorption cycle

Vapor exchange duplex GAX absorption cycle

Coéfficients de performance de machines à froid monoétagée: 0.8 a 1.6 selon le procédée de gestion de chaleur de réaction

Double-effect, triple-effect and quadruple-effect absorption machines

The concept of ‘reverse rectification’, exergy analysis and applications

Nouveaux principes et nouvelles structures de pompes à chaleur à absorption

Entropie

Advanced absorption cycle: vapor exchange GAX

Lithiumbromid-Wasser-Lösungen als Absorber für Ammoniac oder Methylamin

Brennst-Wärme-Kraft

Advances in working fluids and cycles for absorption systems