Development of an exegy based algorithm for the design of hybrid systems using combined heat and power systems and renewable energy resources in the agricultural sector

The prerequisite for minimizing the exergy destructions in the built environment is to base energy-efficient hybrid renewable energy systems on a good balance between the supply and demand of exergy. The aim of this study is to develop a novel decision-making algorithm with MS Excel by modeling various scenarios within to ensure the most appropriate way of allocating the supply exergy among various demands with different exergies and to attain the highest average rational exergy management efficiency in the built environment. The potential positive impact of the algorithm to energy efficiency, CO2 emissions, and fuel savings have been investigated and were rated with a sample design regarding a green farm. In this respect, four scenarios were considered with the objective of minimizing the average rational management efficiency and a composite objective function was compared to a basic scenario about furnishing the power and energy demand of the farm. In the composite objective function, the ratio of exergy efficiency improvement, carbon dioxide emissions reductions and simple payback period reduction between those scenarios were compiled and calculations were made. According to the sample results that were collected, the rational exergy management efficiency was reached with value 0.55 in green farm that had renewable energy methods like combined heat and power, heat pump and solar and wind energy. In the same scenario, it's observed in the main scenario that the carbon dioxide emissions measured as 571 tons CO2/year were drastically reduced to 61 tons CO2/year. The applicability and competence level of the algorithm were tested with the accepted sample values. The simple payback periods were analyzed by calculating the initial investment costs of energy conversion systems and energy/fuel costs with the determined sample values in those scenarios. KEY WORDS: Combined heat and power systems, rational exergy management model, carbon dioxide emissions, renewable energy, green farms, fuel saving, payback period.