Thermoeconomic analysis of reducing exergy losses in greenhouses with hydroponic cultivation system through drainage recycling and formation of water quality pyramid

Employing non-conventional water resources using treatment and recycling is considered as the main resource in addressing future water scarcity. Although non-conventional water recycling has been investigated in details in the literature, its impacts on irrigation-fertilizing systems have not been discussed using thermoeconomic analysis.  In this case study, using a hydroponic greenhouse system for rose cultivation, exergoeconomic cost was investigated in a recycling process by comparing three system including: open cycle, open cycle considering exergy abatement cost, and close cycle (nutrition water recycling). Results show that the exergoeconomic cost for producing 212,500 rose cut-flowers in a 6-months cold period, where heat was supplied by boiler for the above mentioned scenarios were about 15,760 $, 16,525 $ and 14,718 $, respectively. Also, the thermoeconomic indicator of the unit exercoeconomic costs for above mentioned scenarios were 74.2, 77.8 and 69.3 $Gj-1, respectively. In the close cycle, drainage water recycling decreased total exergy losses by 4.02 Gj.yr-1, of which 1.24 Gj.yr-1 reduction was due to the reduced inlet water and 1.91 Gj.yr-1 for the inlet fertilizer reduction, while that increased by the system electricity consumption was 1.12 Gj.yr-1. Water quality pyramid presented based on the unit exergoeconomic cost indicated 459.9 Gj.yr-1 for the nutrition feed  as the highest peak value and zero for the wastewater at the base of the pyramid.