Modelling of an Absorption Cycle with a Direct Ammonia Vapor Generator Inside a Concentrating Parabolic Trough Solar Collector

A desorber-separator for an absorption machine using a parabolic through solar collector has been recently suggested (Lecuona-Neumann et al. 2016). It significantly reduces the complexity and cost of an absorption-cycle based Solar Heating and Cooling facility. A complex flow develops inside the receiver tube: a two-phase, gravity driven and gravity stratified opposite direction currents including boiling of a liquid-solid dissolution, actually NH3-LiNO3. This mixture is both the heat absorbing medium and the working fluid of the absorption cycle. The comprehension of the mutual interactions between cycle and solar direct desorber is necessary in order to unveil the potential of this innovative layout. In the current work, simplified assumptions of the complexity are suggested and implemented in a mathematical model of its integration with a single-effect absorption cycle. The performance of the proposed design has been investigated. Results indicate the importance of the subcooled length and the improvement obtained with lower mass fluxes.