Micro-generation and micro combined heat and power generation using “free” low temperature heat sources through Organic Rankine cycles

Abstract

The Organic Rankine Cycle (ORC) technology is a n efficient way for small-scale generation. It offers great benefits from low temperature heat sources, recovering waste heat and revaluing renewable thermal energy. This paper presents the use of ORC for power and combined heat and power generation from low temperature heat sources. Specifically, two recent applications successfully implemented in Spain are reported, based on Rank® technology: a micro generation for waste heat recovery in a ceramic industry using HT-20 kWe and a micro combined heat and power generation using solar heat with HT-C 5 kWe. Experimental data have been evaluated to check economical and technical ORC feasibility. From waste heat recovery, now up to 23 kWe are generated, 336 MWt of primary energy are saved and 44 tonnes of CO2 emissions are avoided, with a suitable payback lower than 5 years. From renewable thermal energy, now 37 MWt of primary energy are saved, 5 tonnes of CO2 emissions are avoided with a payback lower than 8 years.