Investigation of Novel Configuration for Dual Organic Rankine Cycle Configurations for maximization of waste heat utilization.

Thermal cycles based Organic Rankine Cycle (ORC) are nowadays the most convenient method for conversion of the low-temperature heat to electricity. Alternative concepts combining (cascading) multiple are being investigated yet the theoretical efficiency gain hardly satisfies the added complexity and uncertainty. A common approach is a dual ORC (DORC) which splits the heat input into two serial cycles. ORCs match the temperature profile rather well but cascading configurations exhibit large exergy loss from the superheated vapours during heat rejection. This work presents a thorough theoretical analysis of a novel configuration of DORC for better utilization of the waste heat source. The high-temperature (HT) cycle is designed to exploit maximum energy from the heat source and to condense near ambient. The heat input into the low-temperature (LT) cycle is driven only by the vapour desuperheating after the expansion in the HT cycle. This configuration is compared to a simple ORC configuration.