Volume 2: Innovative Solutions for Energy Transitions: Part I

Optimal Flash Evaporation Temperatures for Geothermal Flash Rankine Cycles Using Pentane Dongyu Meng , Qiang Liu* , Ran Chen, Zhongli Ji

Abstract

Organic Flash Cycles (OFCs) are preferred to convert low temperature geothermal energy to electricity. In this work, comparative studies on two kinds of systems aiming to recover the heat of the saturated liquid after flash evaporation are presented. Modified OFC (MOFC) mixes the saturated liquid after flashing with the cold working fluid to recover the heat of liquid after flashing. Regenerative OFC (ROFC) that use an internal heat exchanger to recover the part of heat of saturated liquid after flashing. The flash temperatures for Basic OFC (BOFC), ROFC and MOFC using pentane were optimized to maximize the net power outputs at various condensation temperatures. Results shows that recovering the heat of liquid after flashing leads to system performance improving, irreversible loss decrease and change of locations of pinch points.

Keywords Organic Flash Cycles, geothermal energy, internal heat exchanger, flash evaporation temperature, condensation temperature