PSI - Issue 77

Arian Semedo and João Garcia/ Structural Integrity Procedia 00 (2026) 000–000

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Arian Semedo et al. / Procedia Structural Integrity 77 (2026) 498–511

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P – Generated power (W) V – Wind velocity (m/s) A – Area of rotor (m 2 ) ρ – Air density (kg/m 3 )

The actual power output of a wind turbine rotor is determined by the efficiency with which kinetic energy from the wind is converted into mechanical energy by the rotor. This efficiency is commonly expressed as the power coefficient, denoted as Cp which quantifies the fraction of available wind power that can be harnessed by the rotor. The relationship is defined by Equation (6) [23]. Cp= 2 ρ 3 (6) PT – Turbine developed power (W) Cp – Characteristic coefficient (dimensionless). It is noteworthy that, although the mechanical energy output of wind turbines can be estimated using standard aerodynamic equations, the electrical power injected into the grid was determined based on the manufacturer-specified power curve of the selected turbine model as a function of wind speed, as provided in the supplementary material. This approach ensures a realistic and accurate representation of turbine performance across varying operational conditions, supporting reliable integration assessments within energy systems.

3.2. Photovoltaic Energy

Photovoltaic (PV) energy enhances refrigeration sustainability. Hameed et al. (2013) confirmed its effectiveness in reducing grid dependence, while Yvon et al. (2021) demonstrated its compatibility with vapor compression systems. A conventional PV system consists of solar panels, inverters, and storage batteries (Pinho and Galdino (2014)). Its efficiency is given by

η ss [%] = η cp ∙ η rc ∙ η bt ∙ η is

(7)

Equation (7) (Pakkiraiah and Sukumar (2016)): η Cp − Cable performance η rc − Performance of solar charge controller η bt − Battery performance η is − Inverter Performance

The power capacity of the photovoltaic panel array is designed to supply approximately fifty percent of the daily energy demand of the refrigeration facility. The system sizing is based on the solar availability for the month of December, which corresponds to the period of lowest solar irradiance in Tarrafal, Cape Verde. The maximum power capacity required for the photovoltaic panel array is determined by Equation (8) (Umar et al (2018)). Table 2 provides key system parameters (PVGIS European Union (2023)). P PVS [kWh] = Loads η ss ∙ PHS (8) PHS-Peak Solar Hours (hours/day)