Energetic, Operational and Environmental Study of Working fluids for low-temperature Organic Rankine Cycles

In this study, Organic Rankine power cycle (ORC) utilizing low-temperature renewable energy sources such as solar or geothermal was presented. Operating temperature of ORC 250ºC was considered as a basis of comparison. Seven working fluids in the ORC were studied from an energetic, operational, and environmental point of view. Working fluids considered were HFE7000, R11, R123, n-decane, Isopentane, n-butane and R245fa. From the point of view of cycle efficiency, n-decane presents the best performance, resulting in the minimum heat input. However, this fluid has the highest system initial cost. The best candidates for the cycle regarding all the considered aspects were found to be: R11, R123 Isopentane and HFE7000. Comparing these four fluids, R123 presents the highet efficiency and the minimum pump power consumption and with low impact in environment. Isopentane presents the high cycle efficiency and biggest vapor specific volume, but is the fluid with higher flammability. R11 presents the highe cycle efficiency and with highest impact in environment but good fluid from safety criteria.HFE7100 is a good working fluid from environmental and safety respects

Energetic, Operational and Environmental Study of Working fluids for low-temperature Organic Rankine Cycles Keywords:

low-temperature Organic Rankine Cycle , Thermodynamic study , Organic working fluid , Environmental consideration