Off-design modelling of an organic Rankine cycle micro-CHP: Modular framework, calibration and validation

The model is calibrated and validated in tests in which 0.1 kg/s of water was heated from 20 °C to 30-36 °C, and 80-500 W mechanical power was delivered at the expander shaft, sweeping restrict ranges of three control variables: burner thermal power of combustion (10-14.5 kWt), pump (500-740 rpm) and expander (2500-2750 rpm) rotation speeds. The model predicts most output variables with acceptable errors, e.g., less than ±10% for the expander outlet pressure (190-220 kPa, abs) or the temperatures at the outlet of the evaporator (80-150 °C) or the expander (60-120 °C).