Performance Assessment of Spectrum Selective Nanofluid-Based Cooling for a Self-Sustaining Greenhouse

In hot climatic conditions, the temperature inside a greenhouse is much higher than the ambient temperature and requires significant cooling to maintain the temperature in the optimal range. This study proposes a novel concept for a self-sustaining greenhouse, which integrates evacuated tube collectors, a multistage flash desalination system, vapor absorption cooling system, and photovoltaic thermal (PV/T) system to produce freshwater, cooling, and electricity. The PV/T system uses spectrum selective nanofluid that is circulated over the roof of the greenhouse and absorbs solar radiation having wavelengths greater than 1400 nm to reduce cooling load inside the greenhouse and optimize the spectrum use. The performance of the proposed system is evaluated using energy and exergy analysis. The energy efficiencies of the evacuated tube collector, desalination unit, and PV/T system are obtained as 45.85%, 46.16%, and 51.25%, respectively. The absorption cooling system achieves an energetic coefficient of performance of 0.83. The overall energy and exergy efficiencies of the proposed system are found to be 30% and 5.88%, respectively. The application of spectrum selective nanofluid on the roof of the greenhouse yields about 26% reduction in the cooling load of the greenhouse.