| Real | pi | Modelica.Constants.pi | |
| Modelica.SIunits.Area | S_net | 41 | Net Collecting Surface |
| Modelica.SIunits.Length | A_P | 2.37 | Aperture of the parabola |
| Modelica.SIunits.Length | Dext_t | 0.04 | External diameter tube |
| Modelica.SIunits.Length | th_t | 0.004 | tube thickness |
| Modelica.SIunits.Length | L | S_net/A_P | length of tubes |
| Modelica.SIunits.Area | A_ext_t | pi*Dext_t*L | Lateral external area of the tube |
| Modelica.SIunits.Area | S_ext_t | Dext_t*L | target surface of incoming radiation from the sun (Cross section without concentration) |
| Modelica.SIunits.Length | D_int_t | Dext_t - 2*th_t | internal diameter of the metal tube |
| Modelica.SIunits.Area | A_int_t | L*D_int_t*pi | Lateral internal surface of the metal tube |
| Modelica.SIunits.Volume | V_tube_int | pi*D_int_t^2/4*L | Internal volume of the metal tube |
| Real | A_0 | 1 | |
| Real | A_1 | 5.00396825E-04 | |
| Real | A_2 | -1.65000000E-04 | |
| Real | A_3 | -2 - 6.94444444E-07 | |