To generate MATLAB code for waste heat recovery by an organic Rankine cycle (ORC), you can follow these steps:
Step 1: Define the System Parameters Start by defining the necessary system parameters such as the working fluid properties, heat source conditions, and ORC cycle parameters. These parameters include fluid properties (e.g., critical temperature, enthalpy, entropy), heat source temperature, ambient temperature, ORC cycle efficiency, and heat exchanger characteristics.
Step 2: Determine Thermodynamic Properties Using the defined working fluid properties, you need to calculate the thermodynamic properties of the fluid at different points in the ORC cycle. This can be done using appropriate equations or property tables for the specific working fluid. The properties required for calculations include enthalpy, entropy, temperature, pressure, and specific volume.
Step 3: Perform Iterative Calculations To simulate the ORC cycle, you need to perform iterative calculations to find the operating conditions at each point in the cycle. This typically involves solving a set of equations based on mass and energy conservation principles. The specific equations will depend on the type of ORC cycle (e.g., subcritical, transcritical) and the assumptions made.
Step 4: Calculate Heat Transfer and Power Output Once you have determined the operating conditions at each point in the ORC cycle, you can calculate the heat transfer rates and power output. This involves calculating the heat transfer between the heat source and the working fluid, as well as the heat transfer between the working fluid and the heat sink (usually ambient air). The power output can be calculated using the mass flow rate of the working fluid and the specific enthalpy difference across the turbine.
Step 5: Perform Sensitivity Analysis (Optional) If desired, you can perform sensitivity analysis by varying certain system parameters (e.g., heat source temperature, ORC cycle efficiency) to evaluate their impact on the ORC performance. This can help optimize the system design or assess different operating scenarios.
Here is a sample MATLAB code skeleton that can be used as a starting point:
matlab