Experimental investigation of a biomass-fuelled micro-scale tri-generation system with an organic Rankine cycle and liquid desiccant cooling unit

The drastic rise in the conventional fossil fuel prices along with the global warming and climate change have urged the need to switch towards renewable energy resources and use alternative means for more efficient energy resources utilization. Tri-generation technology has attracted considerable interest as a potential alternative to separate conventional energy production with a wide range of applications especially for small-scale systems providing various technical, economic and environmental benefits. In this study, an innovative micro-scale tri-generation system was experimentally investigated, consisting of an organic Rankine-based combined heat and power unit and a combined dehumidification and cooling unit. A compact and low-cost modified scroll expander was employed in the Rankine unit for heat and power generation. In addition, a liquid-desiccant unit coupled with a dew point evaporative cooler was used to provide the cooling capacity through air dehumidification and cooling. An experimental setup was built and the micro-scale tri-generation system was tested under different operational conditions employing a wood pellet biomass boiler as a heating source. It is shown that the proposed system is capable of providing about 9.6 kW heating power, 6.5 kW cooling power and 500 W electric power. The overall efficiency of the tri-generation system is about 85%.