Potential development of organic Rankine cycle (ORC) power generation system by utilizing heat from natural hot-spring in Malaysia

Abstract

Organic Rankine Cycle (ORC) is widely used because of its ability to work with low and medium-grade heat resources. ORC basically operate by using organic working fluid which allows the application of Rankine Cycle to be operate at various range of heat resources depend on the properties of working fluid. This allows wide application of ORC power cycle at temperature below 370 °C where the steam-based Rankine Cycle are no longer efficient. This present paper discusses the potential development of micro power generation based on the ORC concept by utilizing heat from natural hot spring in Malaysia. The performance of the systems is analysed based on three different working fluids which are R134a, R410a and R245-fa. The comparison was done by the variation of hot water inlet temperatures in the range of 50 °C to 75 °C at the evaporator and 25 °C of ambient water at the condenser. The results indicates that R245-fa had 9 % thermal efficiency when the hot water inlet temperature is 75 °C which is the highest among the other working fluids in the similar condition. Meanwhile, the ideal power output of turbine is also analysed. The R410 can generate 2.38 kW power output when the input temperature of hot water is 75 °C which is the highest as compared to other working fluid at similar condition. Therefore, it can conclude that the micro-scale power generation systems can be developed based on ORC power cycle by utilizing heat resources by natural hot spring in Malaysia.