Table 41 Value of the constants used to compute the overall efficiency of the parabolic trough collectors. (Franchini et al., 2013) A 77.8 B -0.022 C 0.5 D -0.033 The effectiveness of the evaporator is computes as (Lozza, 2007): (4.7) Since the water is evaporating, the fluid with the lowest thermal capacity is the thermal oil. The maximum temperature drop is achieved when the heat transfer fluid is ideally cooled to the evaporation temperature. The inlet temperature of the thermal oil is fixed to 390 °C, while the temperature at the outlet section of the evaporator is 290°C. The enthalpies of the water/steam are computed using the software Refprop. The evaporation temperature and pressure are computed following the same procedure used for the SHCC system (see Chapter 2). The work required to the pump to circulate depends on the pressurization level of the liquid thermal oil can be computed as: (4.8) The density of the fluid is calculated at the inlet section of the pump using the empirical correlation available in Therminol data-sheet (Solutia, 2014 ). The required mass flow rate of Therminol is determined considering the energy balance at the solar evaporator: (4.9) The value for the thermal oil enthalpy can be found in the Therminol data-sheet (Solutia, 2014 ).
Table 41 Value of the constants used to compute the overall efficiency of the parabolic trough collectors. (Franchini et al., 2013) A 77.8 B -0.022 C 0.5 D -0.033 The effectiveness of the evaporator is computes as (Lozza, 2007): (4.7) Since the water is evaporating, the fluid with the lowest thermal capacity is the thermal oil. The maximum temperature drop is achieved when the heat transfer fluid is ideally cooled to the evaporation temperature. The inlet temperature of the thermal oil is fixed to 390 °C, while the temperature at the outlet section of the evaporator is 290°C. The enthalpies of the water/steam are computed using the software Refprop. The evaporation temperature and pressure are computed following the same procedure used for the SHCC system (see Chapter 2). The work required to the pump to circulate depends on the pressurization level of the liquid thermal oil can be computed as: (4.8) The density of the fluid is calculated at the inlet section of the pump using the empirical correlation available in Therminol data-sheet (Solutia, 2014 ). The required mass flow rate of Therminol is determined considering the energy balance at the solar evaporator: (4.9) The value for the thermal oil enthalpy can be found in the Therminol data-sheet (Solutia, 2014 ).
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