NY-91-02-1 -- A Simplified, High-Efficiency DUBLSORB System PDF

DUBLSORB is the name given to the broad class of hybrid absorption and liquid desiccant cycles where heat usually rejected from an absorption chiller to a cooling tower is used to provide at least a portion of the liquid desiccant regeneration heat. The initial development was a basic cycle where heat from the condenser of an absorption chiller drove the desiccant regenerator. With this basic cycle, direct-fired heating of the regenerator was necessary when the latent load was more than 25% of the total cooling load. In other developments reported previously, DUBLSORB systems were defined that could respond efficiently to the load regardless of the ratio of latent load to total load but with increases in the level of system complexity. The new system presented here is the result of evaluating the alternative trade-offs among several of the DUBLSORB concept variations. Compared with other DUBLSORB systems, simplicity is achieved in this new system, solution additives are minimised, spindown to lower concentrations is eased, performance is improved, and any amount of latent load is efficiently handled without an auxiliary burner. A representative seasonal coefficient of performance (COP) of 1.5 is predicted. This system is expected to require little special engineering for each application. Once the design sensible load for a given building is determined, this system is expected to provide adequate latent capability for almost all applications. For minimum first cost, the liquid desiccant dehumidifier would be sized for the latent load, recognising that additional dehumidification capability could be added if the latent load is larger than anticipated. In addition, the system is expected to be quite forgiving under overload conditions in that latent load capability can be maintained, even though sensible load capability is inadequate. This system should provide a major improvement in comfort when contrasted with more conventional systems in which an overload causes loss of control of both sensible and latent loads.

KEYWORDS: absorption refrigeration, desiccants, heat exchangers, dehumidifiers, comparing, performance, coefficient of performance, efficiency