Simulation of absorption power cycle and organic Rankine cycle using evacuated tube solar collectors.

Abstract

Absorption power cycles (APC) working with LiBr-H2O working fluid, serve as an alternative to ORC for micro-scale applications. The APC, similarly to zeotropic ORC, has an advantage of higher exergy efficiency of heat exchangers by smoother temperature match of hot and cold fluids provided by temperature glide of the working fluid. This work explores application with evacuated tube solar collectors a prospective low temperature heat source. Such configuration may be interesting for buildings application, offering to use excess of the thermal energy for electricity production. A model is developed coupling performance of the heat engine (APC and ORC) with the collectors. Behaviour and overall performance of such system is estimated based on weather data for one year. The results are compared to performance of photovoltaic modules. The models show lower potential for heat engines power production, but the APC system especially can be beneficial for its possibilities of thermal integration.