Absorption power cycle (APC) working with LiBr-H2O solution as a working fluid has been recently identified as a prospective option power production for low temperature and small output (1-10 kW) applications. Different boiling temperatures of the solution components cause a temperature glide during evaporation and condensation (instead of isothermal process for single-component fluid), which can decrease exergy losses during heat exchange processes. The cycle can also operate in a regime of partial power production and partially as an absorption chiller.
Thermodynamic properties of the working fluid give a very interesting performance in comparison to ORC as well as standard Kalina cycle. On the other hand the whole cycle (high and low pressure) operates at sub-ambient pressure with large volumetric flows. However, this gives a potential for high turboexpander efficiency for power output in order of several kW. This concept of APC also brings many challenges for the real-life system as actual temperature profile in heat exchangers with temperature glide phase change, purity of the steam going to the expander concerning the liquid solution droplets, actual air tight operation and limiting of corrosion in the system.
Therefore and experimental rig for validation of these aspects has been built. Its specific design, methods for components’ sizing and first experimental results which tackle some of the mentioned challenges are presented in this work. Results are presented for design of experimental desorber, vapour separator and general system of the rig which has been built in current phase of larger experimental intentions. First results with water instead of LiBr solution give suggestions of required desorber configuration. Expander, absorber or eventually also parallel absorption chiller operation is under planning as a future work.
