An organic Rankine cycle(ORC) unit is designed through thermodynamic analysis and equipment type selection under geothermal conditions. Then

this unit is simulated to study its dynamic operating characteristics and investigate the influences of four parameters

such as heat source temperature

mass flow rate

cooling water temperature and working fluid mass flow rate

on key operating parameters and performance of the ORC unit. The results show that

the output performance of the unit is primarily affected by the cooling water temperature. An increase of 10 ℃ in the heat and cold source temperatures results in a decrease of 16% and an increase of 7% in the output power

respectively. The increased heat source temperature and mass flow rate will make the degree of superheat

evaporating pressure and shaft work increase significantly

and the system thermal efficiency decrease slightly. However

the effect of increasing heat source temperature and mass flow rate on the heat transfer of the cold side is limited

that on the hot side heat transfer is also neglectable

so the vapor superheat and evaporating pressure remains constant. Compared with the change of cold and heat source parameters

the change of working fluid mass flow rate has the lowest overshoot of parameters during dynamic operation of the unit

and the unit can reach the next steady state rapidly.