Energy and economic evaluation of a middle-sized CSP parabolic field in an agro-industrial company

The energy assessment carried out in a middle-sized CSP parabolic field of 120 m² is presented; it provides pre-heating water at 70°C to the boilers of the lemon essential oil extraction process in an agro-industrial company located in Piura, at the border of Sechura desert in Peru. The parabolic cylindrical solar concentrators are made with glass reflectors, an automatic solar tracking system, and collector tubes through which water flows. It was measured that each collector converts solar energy and transfer it as a thermal energy to the water with an average efficiency of 18.1%. Considering this result, theoretically the whole solar field could provide 550.37 GJ/year for water preheating, which is equivalent to saving 28151.8 liters of LPG, and 46.87 tons of CO₂ released to the environment. However, after a year of operation, the solar field provided only 99.59 GJ for water preheating, saving 4 705.26 liters of LPG, equivalent to stop emitting 7.69 tons of CO₂ to the environment. An overall thermal energy efficiency of the CSP solar field in 18.1% was estimated. According to the financial assessment with the actual annual data, the period of recovery of the investment is estimated to be 4.4 years, 3.6 more years than theoretical projection.