Experimental assessment of a compact branched tray generator for ammonia-water desorption

An experimental investigation of heat and mass transfer in a miniaturized ammonia-water desorber utilizing microscale geometries is presented. The desorber, sized for a 3.5-kW space-conditioning system, is of a branched tray design consisting of an array of alternating plates with integral microscale features enclosed between cover plates. The desorber is hydronically coupled to a heat transfer fluid that is heated by the combustion of natural gas. An adiabatic analyzer and solution cooled rectifier are integrated into the same envelope as the desorber. The component is tested as part of a single-pressure system on a breadboard test facility and is studied over a range of heat transfer fluid inlet temperatures, flow rates, and concentrated solution flow rates. Desorber performance is experimentally investigated over a wide range of test conditions to improve the understanding of performance at design and off-design conditions and the potential for flow instabilities.